Hawaiian monk seals primarily prey upon teleost fishes, which make up roughly 80% of their diet. They appear to prefer fish belonging to the families Muranidae (marine eels), Labridae (wrasses), Holocentridae (squirrelfishes and soldierfishes), Balistidae (triggerfishes) and Scaridae (parrotfishes). Except for the beardfish family (Polymixiidae), which consists of deep sea benthic fishes, all fishes consumed by Hawaiian monk seals are shallow reef fishes (Goodman-Lowe, 1998). The remainder of the their diet consists of cephalopods and crustaceans, with the majority of consumed cephalopods being octopi. Hawaiian monk seals prey upon diurnal and nocturnal species of teleosts and cephalopods; however, juveniles tend to prey more heavily on nocturnal species (Goodman-Lowe, 1998). They primarily forage in shallow reefs (less than 100 m) near their natal atoll and foraging takes place near or at the sea floor. Individuals foraging in precious coral beds (Corallium rubrum) at depths of over 300 m have been recorded, where prey-capture rates may be higher (Parrish et al., 2002).
Animal Foods: fish; mollusks; aquatic crustaceans
Primary Diet: carnivore (Piscivore , Molluscivore )
Hawaiian monk seals communicate using vocalizations, including those between mothers and nursing pups.
Communication Channels: acoustic
Perception Channels: tactile ; acoustic ; chemical
Hawaiian monk seals have been on the United States Fish and Wildlife Service’s endangered species list since November 23, 1976 and are listed as critically endangered on the IUCN Red List of Threatened Species. They have been in decline for over 20 years, and as of 2007, only 1200 individuals remained in the wild. Experts estimate that fewer than 1000 individuals will remain in the wild by the end of 2012. Efforts by the National Marine Fisheries Service to stabilize population numbers include keeping tourists away from known reproductive sites, moving aggressive males to new breeding grounds, and implementing a captive care program, which provides females with nutritional supplements. The goal of the captive care program is to increase the survival rate of female juvenile seals, which have an extremely low survival rate. Hawaiian monk seals are vulnerable to introduced disease, inbreeding depression, low genetic diversity, human disturbance, and competition with fisheries. In addition to the U.S. Fish and Wildlife Service’s Endangered Species Act, they are also protected under the Marine Mammal Protection Act.
Hawaiian monk seals are intolerant of human disturbance on beaches used for birthing and resting, and pup mortality is often higher at disturbed sites. Hawaiian monk seals began declining in the mid to late 1800’s, when they were hunted for their meat and skins. Currently, populations are declining due to over fishing and seals becoming hooked or entangled in fishing gear (Antonelis et al., 2003).
US Federal List: endangered
CITES: appendix i
State of Michigan List: no special status
IUCN Red List of Threatened Species: critically endangered
Present day Hawaiian monk seal populations represent a fraction of their historical abundances. Although recovery efforts are now underway, the total cost of these efforts over the next 50 years is estimated to be about 385 million dollars. Also, in compliance with the National Marine Fisheries Service recovery plan for Hawaiian monk seals, important feeding and reproductive sites, typically beaches, have been closed to public access. Finally, they occasionally remove fish from commercial trolling lines.
Currently, Hawaiian monk seals have little to no economic importance. However, during the mid-19th century, when Hawaii was first claimed by the United States, Hawaiian monk seals were killed for their skin, oil, and meat.
Hawaiian monk seals prey upon 40 species of marine animals that live in the coral reef ecosystem, including many species of teleost fish, cephalopods, and crustaceans.
Hawaiian monk seals are endemic to the Hawaiian Archipelago and are found primarily in the tropical waters of the northwestern Hawaiian island chain. Reproductive sites include Kure atoll, Midway atoll, Pearl and Hermes Reef, Lisianski Island, and French frigate shoals. Small populations also occur on Necker and Nihoa and breeding populations have been found on the main Hawaiian islands, also known as the windward Hawaiian Islands (Baker and Johannos, 2004; Antonelis et al., 2003).
Biogeographic Regions: pacific ocean (Native )
Other Geographic Terms: island endemic
Hawaiian monk seals utilize terrestrial and marine habitats. Sandy beaches are used for parturition, nursing, molting, and resting. The most common parturition sites are on sandy beaches with exposed protective reefs, which limit shark access and provide shelter from large surf (Atonelis et al., 2003). Hawaiian monk seals use protected waters to teach weaned pups to capture prey. They use vegetation along the beach perimeter to protect themselves from ultraviolet rays, wind, and rain, and may also use terrestrial vegetation as shelter while they sleep (Gilmartin, 1983). Hawaiian monk seals spend the majority of their time in the ocean resting, interacting with each other, and foraging. They spend much of their time at depths of about 100 m and less, although some have been observed foraging at depths of over 300 meters (Parish et al., 2002).
Range depth: 300 (high) m.
Average depth: 100 m.
Habitat Regions: tropical ; terrestrial ; saltwater or marine
Aquatic Biomes: reef
Hawaiian monk seals live for 25 to 30 years in the wild. The lifespan of captive individuals is unknown.
Average lifespan
Status: wild: 25 years.
Average lifespan
Status: wild: 30.0 years.
Hawaiian monk seals exhibit sexual dimorphism, with females being larger than males. Females have an average length of 2.25 m and an average weight of 203 kg. Males have an average length of 2.1 m and an average weight of 169 kg. After birth, Hawaiian monk seals are covered in black lunago (fetal hair), which they molt upon weaning. As juveniles, they are silvery gray, with darker hair on their dorsal side and white hair on their ventral side (National Marine Fisheries Service, 2007). Adults have brown pelage that is slightly gray on their backs and gradually fades to yellow and then white near the ventral surface of the animal. They have broad, flat, and moderately small heads with large black eyes. Unlike other pinnipeds, their nostrils are located on top of their short snout.
Range mass: 169 to 203 kg.
Range length: 2.1 to 2.25 m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger
The main predator of Hawaiian monk seals is the tiger shark (Galeocerdo cuvier), and shark predation is believed to be a significant contributing factor to pup mortality. Although male Hawaiian monk seals are known to commit infanticide, sharks are thought to be the main threat to pup survival. Seals avoid potential predators by nesting on beaches protected by exposed reefs and by feeding and resting in underwater reef caves.
Known Predators:
Copulation in Hawaiian monk seals is rarely observed but usually takes place about 1 to 5 km off shore. Although little is known about the reproductive success or the mating system used by these animals, sexual dimorphism in conjunction with open water mating suggests polygyny (Weckerly, 1998). As in other pinnipeds, males likely mount females by biting their backs and grasping them with their foreflippers (Antonelis et al., 2003).
Mating System: polygynous
Hawaiian monk seals are monestrous and give birth to a single pup each year during an extended birthing season, which begins in March, peaks in April, and ends in August (Boness et al., 1998). Females leave the ocean to give birth on beaches close to their most recent breeding site. Birthing takes place after an 11-month gestation period, which contains a 3-month period of delayed implantation. Females are solely responsible for rearing offspring, which takes about 40 days. While rearing their pups, females fast and may lose hundreds of pounds. Pups weigh between 14 and 17 kg at birth and between 50 and 100 kg at weaning (National Marine Fisheries Service, 2007). Females wean pups by suddenly abandoning them and returning to the ocean, after which they wait 3 to 4 weeks before mating again (Boness et al., 1998). Hawaiian monk seals are one of three pinniped species that commonly foster pups, the other two being grey seals (Halichoerus grypus) and northern elephant seals (Mirounga angustirostris; Boness et al., 1998). Both genders reach sexual maturity between the ages of 5 and 10 years old. Pups weaned at higher weights generally have a greater chance of survival and become sexually mature at an earlier age.
Breeding interval: Hawaiian monk seals breed once yearly
Breeding season: February to March
Average number of offspring: 1.
Average gestation period: 11 months.
Range weaning age: 5 to 6 weeks.
Range age at sexual or reproductive maturity (female): 5 to 10 years.
Range age at sexual or reproductive maturity (male): 5 (low) years.
Average age at sexual or reproductive maturity (male): 10 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; delayed implantation
Average birth mass: 17000 g.
Average gestation period: 335 days.
Average number of offspring: 1.
Females are the only sex that invest in pup development. Pup fostering, which only occurs in 2 other pinniped species (gray seals, Halichoerus grypus and northern elephant seals, Mirounga angustirostris), takes place when females rear their young in close proximity to one another and may occur when pups are separated from their mothers. Most females tolerate nursing attempts by orphaned pups. Although pup fostering appears to result in little to no reward for adopting mothers, fostered pups clearly benefit from their foster mother's care (Boness et al., 1998).
Parental Investment: female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
Havay monax suiti (lat. Monachus schauinslandi) — Əsl suitilər fəsiləsinə aid növ.
Uzunluğu 225 sm, rəngi isə tünd qəhvəyi və ya tünd boz-qəhvəyi olur. Dişilər isə nisbətən açıq rəngdə olurlar. Erkəklər bir qayda olaraq dişilərdən iri olur.
Havay suitiləri Havay adalarının şimal-qərbdə yerləşən atol atol adalarında yayılmışdır. Əsasən Kure, Perl end Hermes, Frenç Friqat Şols, Miduey adalarında yaşayırlar. Əvvəllər isə hətta Kayay, Havay, Niihau, Oahu adaları sahilləri ərazisində də yaşayırdılar.
1958- 1996 ci illərdə onların sayı 60% azalmışdır. 2004-ci ildə isə onların sayı 1400 başa çatmışdır. Əvvəllər onların sayının azalmasının səbəbi kütləvi ovlanma idisə, indi isə balıqçı torlarıdır. ABŞ-da qanunla qorunur. Əsasən balıq və Molusklarla qidalanır.
Bu növün balavermə dövrü dekabrdan avqust ayına qədər davam edir. Ən aktiv dövr aprel may aylarıdır. Balanın çəkisi 16 kq, uzunluğu 125 sm olur. Onlar qara yumşaq kürkünü 3-5 həftə ərzində dəyişir. Rəngləri gümüşü-boz-mavi alır. Kürək nahiyyəsində isə gümüşü-ağ ləkə vardır. Dişilər iki ilə bir bala verir. Çütləşmə dönəmi may noyabr aylarını əhatə edir.
Havay monax suiti (lat. Monachus schauinslandi) — Əsl suitilər fəsiləsinə aid növ.
Reunig manac'h Hawaii (Monachus schauinslandi) a zo ur bronneg mor hag a vev er meurvor Habask.
La foca monjo de Hawaii (Monachus schauinslandi) és una espècie de mamífer marí de la família de les foques que viu a les aigües càlides que envolten les illes del nord-est de l'arxipèlag de Hawaii. És rar observar-la a les illes més grans.
La foca monjo de Hawaii (Monachus schauinslandi) és una espècie de mamífer marí de la família de les foques que viu a les aigües càlides que envolten les illes del nord-est de l'arxipèlag de Hawaii. És rar observar-la a les illes més grans.
Tuleň havajský (Monachus schauinslandi) je jediný druh tuleně žijícího v tropických vodách.
Je endemitem havajského souostroví kde se nejčastěji vyskytuje v jeho severozápadní části. Při reprodukci se největší část populace shromažďuje na řetězci odlehlých severozápadních ostrovů v šesti skupinkách na: French Frigate Shoals, Laysan Island, Lisianski Island, Pearl and Hermes Reef, Kure Atoll a Midway Atoll. Malé populace se také vyskytuji na Necker Island a Nihoa Island, v poslední době byly také nalezeny skupinky na Windward Hawaiian Islands u hlavních havajských ostrovů.
Vybírají si místa s poměrně krátkými plážemi a plytkou vodou u pobřeží nebo na písečných plážích za útesy, chrání se tak před napadením svých mláďat žraloky. Nejraději mají pobřeží kde je v blízkosti vody vzrostlá vegetace (tráva, keře) ve které nacházejí stín a mohou se chránit před UV zářením a skrýt se při spánku.
Samci jsou u tohoto druhu menší a lehčí než samice. Samci váží v průměru 170 kg a měří 2,1 m, samice váží 205 kg a měří 2,3 m. Narozené mládě je dlouhé 1 m. Na zádech jsou zbarveni hnědě až stříbřitě šedě a krémově na břišní straně. Dále mají po těle různé nazelenalé a načervenalé skvrny pocházející z řas, barva samců tmavne s věkem. Novorozenci jsou pokryti černými chlupy, po odstavení jim vylínají. Mají široké, ploché, středně velké hlavy s nozdrami na vrcholu krátkého čenichu. Oči mají velké a černé barvy.
Tuleň havajský se živí především rybami čeledí ostencovití, pamurénovití, ploskozubcovití, pruhatcovití, pyskounovití a vousatkovití což jsou převážně ryby mělkých vod v okolí útesů. Zbytek tvoří hlavonožci a korýši. Přestože převážná část loví potravu v hloubce do 100 m, někteří se potápějí za obživou i do 300 m. Většinu potravy kterou spotřebují se nachází průměrně ve vzdálenosti do 40 km od ostrovů.
Mimo období rozmnožování a línání jsou samotářská zvířata která žijí osamoceně nebo jen zřídka kdy v malých skupinkách. Loví převážně v noci a přes den se často vracejí na pevninu odpočívat. Obecně platí, že z 90 % se zdržuje u svého rodného ostrova. Na pevninu se vracejí samci i samice také na dobu asi 14 dnů pro každoroční výměnu srsti.
Jsou to polygamní zvířata, samci se páří s více samicemi. Vlastní akt probíhá ve vodě 1 až 5 km od břehu, takže není o něm mnoho známo, dochází k němu za 3 až 4 týdny po odstavení mláděte. Pravděpodobně se samci při něm zakusují samici do zad a objímají ji předními ploutvemi. V okolí ostrovů již čekají mnohdy agresivní samci na říjnou samici kterou ve skupině doslova přepadnou a dochází pak někdy k jejímu usmrcení.
Březí samice přichází na břeh několik dnů před vrhem, ten probíhá v noci nebo brzy z rána. Samice rodí pouze jedno mládě ročně, zhruba po 11 měsíční březosti, přitom asi 3 měsíce probíhá tzv. utajená březost při které se vývoj zygoty pozastaví.
Porodní sezona probíhá prakticky celoročně, vrcholí v březnu a dubnu. Samice vystupují z vody na pevninu k porodu v místech kde rodily naposled. Nové mládě váží asi 15 kg a při odstavení mívá 50 až 100 kg. Matka mládě kojí 5 až 6 týdnů a neopouští ho, takto bez potravy ztrácí až 90 kg váhy. Po náhlém odstavení odchází matka do moře a o mládě se dále nezajímá. To žije nejprve z tělesných zásob, pak také jde do vody a učí se potápět, lovit a starat se samo o sebe, zde přichází vhod pobřeží které je chráněno před žraloky. V této etapě je největší úbytek mláďat, pouze 20 % se dožívá reprodukčního věku. U tohoto druhu často dochází k tomu, že samice jejíž potomek uhynul příjme za své mládě které zůstalo bez matky nebo pomáhá matce s kojením.
Mezi jejich přirozené predátory patří hlavně žralok tygří, který je hlavní příčinou velkého úhynu mláďat. Tuleň havajský je zvíře dlouhověké, předpokládaná doba dožití je 25 až 30 let, samice poprvé rodí nejdříve v 5. roce.
Podstatná část populace byla odlovena na konci 19. století, kdy byli tulení běžně loveni pro kůže, maso a tuk. Po zastavení lovu byli zase rušeni vojenskou činností za a po 2. světové válce a následně opět zvyšujícím se turistickým ruchem na "jejich" plážích. Přes všechna přijatá opatření a zákazy (zákaz lovu humrů a chytání ryb na dlouhé šňůry, vyčištění pobřežních vod od zbytků rybářských sítí, do kterých se zvířata zamotávají a pod.) se počty nezvyšují, spíše naopak. Je to pravděpodobně způsobeno nedostatkem potravy, jsou pozorovány samice stále menší a chudší a do reprodukčního procesu se zapojují pozdě, až ve věku 11 let.
Za posledních 50 roků pokleslo jejich množství přibližně o 70 %. Od roku 1999 se snižují jejich počty o 4 % ročně. V roce 2007 bylo zjištěno 1010 zvířat a z toho asi 590 pohlavně dospělých. Tuleň havajský je podle IUCN řazen mezi druhy ohrožené.
V mořském akváriu
V mořském akváriu
Pod přesličníkem
Obrázky, zvuky či videa k tématu tuleň havajský ve Wikimedia Commons
Tuleň havajský (Monachus schauinslandi) je jediný druh tuleně žijícího v tropických vodách.
Die Hawaii-Mönchsrobbe (Neomonachus schauinslandi, Synonym: Monachus schauinslandi), auch Laysan-Mönchsrobbe genannt, ist eine vom Aussterben bedrohte Mönchsrobbenart, die endemisch im tropischen Nordpazifik bei Hawaii vorkommt. Der wissenschaftliche Name verweist auf den deutschen Zoologen Hugo Hermann Schauinsland, der 1899 einen Schädel auf Laysan fand.
Hawaii-Mönchsrobben ähneln mit ihrem langgestreckten Körper, dem langen Hals und dem kurzen, breiten Kopf und den kurzen Flippern (Flosse) äußerlich allen anderen Hundsrobben. Weibchen erreichen eine Länge von 2,4 m bei einem Maximalgewicht von über 270 kg, Männchen bleiben mit einer Länge von 2,10 m und einem Gewicht um 200 kg etwas kleiner. Sie sind auf der Oberseite des Körpers silber- bis schiefergrau, die Bauchseite ist cremefarben. Mit fortschreitendem Alter werden sie auf der Oberseite zunehmend bräunlich und auf der Unterseite gelblicher. Zudem können unregelmäßige Flecken auftreten und das Fell kann durch Algen grünlich oder rötlich verfärbt sein. Alte Männchen tragen oft tiefe Narben, die ihnen von Rivalen beim Streit um Weibchen zugefügt wurden. Jungtiere werden mit einem schwarzen, wolligen Fell geboren und haben ein kontrastierendes weißes Maul. Das Haarkleid der ausgewachsenen Tiere ist sehr kurz. Beim Fellwechsel lösen sich auch Fetzen alter Haut. Die Tasthaare an den Seiten der Schnauze sind weich und dunkel mit hellen Spitzen, die Tasthaarfelder dick und fleischig. Die Nasenlöcher der Hawaii-Mönchsrobbe öffnen sich nicht nach vorne, wie bei den meisten anderen Hundsrobben, sondern nach oben.
Die Hawaii-Mönchsrobbe kommt endemisch rund um die Hawaiiinseln vor. Sie entfernen sich normalerweise nur bis zu 140 km von der nächsten Insel. Einzelne Tiere wurden jedoch schon beim Johnston-Atoll, beim Palmyra-Atoll und der Wake-Insel gesichtet. Hawaii-Mönchsrobben haben ein weites Nahrungsspektrum und ernähren sich von Knochenfischen (79 %), Kopffüßern (16 %) und Krebstieren (5 %). Meist werden Meeresaale, Lippfische, Soldaten- und Husarenfische, Drückerfische und Papageifische gefangen.[1] Zum Ausruhen bevorzugen sie terrassierte Felsküsten oder Sand- und Korallensandstrände, die von Vegetation beschattet werden. Außerhalb der Paarungszeit sind die Tiere unsozial und leben allein oder Weibchen zusammen mit ihren Jungen. In Gefahrensituationen zeigen die Robben ihre Bauchseite, reißen das Maul auf und heben einen Flipper.
Die Fortpflanzungszeit dauert von Ende Dezember bis Mitte August. Für Paarung und Geburt werden fast ausschließlich sechs Atolle und kleine Inseln aufgesucht, die nordwestlich der Hauptinseln liegen, darunter die Midwayinseln, das Kure-Atoll, die French Frigate Shoals und die Insel Laysan und Lisianski[2]. Die Männchen versuchen dann Strandabschnitte und die sich darauf aufhaltenden und ihre diesjährigen Jungen säugenden Weibchen unter ihre Kontrolle zu bringen und fechten untereinander heftige Kämpfe aus. In vielen Kolonien gibt es drei Mal so viele adulte Männchen wie geschlechtsreife Weibchen. Hawaii-Mönchsrobben paaren sich im Wasser. Die Jungtiere sind bei der Geburt etwa einen Meter lang und 16 bis 18 kg schwer. Sie werden sechs Wochen gesäugt.
Die IUCN schätzt die Art als vom Aussterben bedroht (Critically Endangered) ein und geht von einer verbleibenden Gesamtpopulation von 600 Tiere aus.[2] Das Pacific Islands Regional Office der NOAA schätzte die Population im Januar 2017 auf 1.400 Individuen.[3] Die genetische Variabilität der verbliebenen Tiere ist sehr gering.[4] Die wichtigsten natürlichen Feinde sind der Tigerhai (Galeocerdo cuvier) und der Galapagoshai (Carcharhinus galapagensis).[5]
Die Hawaii-Mönchsrobbe (Neomonachus schauinslandi, Synonym: Monachus schauinslandi), auch Laysan-Mönchsrobbe genannt, ist eine vom Aussterben bedrohte Mönchsrobbenart, die endemisch im tropischen Nordpazifik bei Hawaii vorkommt. Der wissenschaftliche Name verweist auf den deutschen Zoologen Hugo Hermann Schauinsland, der 1899 einen Schädel auf Laysan fand.
Foka e Havait (Neomonachus schauinslandi, më parë Monachus schauinslandi) është një lloj i rrezikuar i fokave pa veshë, që i takon familjes Phocidae dhe është endemik i Ishujve të Havait.[1]
Foka e Havait është një nga dy llojet e gjalla të fokave murgesha; tjetra është foka e Mesdheut. Një lloj i tretë, foka e Karaibeve, është zhdukur.[2] Foka e Havait është e vetmja fokë autoktone e Havait, dhe së bashku me lakuriqin e Havait, përbëjnë dy gjitarët endemik të ishullit.[3]
Foka e Havait (Neomonachus schauinslandi, më parë Monachus schauinslandi) është një lloj i rrezikuar i fokave pa veshë, që i takon familjes Phocidae dhe është endemik i Ishujve të Havait.
Foka e Havait është një nga dy llojet e gjalla të fokave murgesha; tjetra është foka e Mesdheut. Një lloj i tretë, foka e Karaibeve, është zhdukur. Foka e Havait është e vetmja fokë autoktone e Havait, dhe së bashku me lakuriqin e Havait, përbëjnë dy gjitarët endemik të ishullit.
Η φώκια μοναχός της Χαβάης (Monachus schauinslandi - Μοναχός του Σάουινσλαντ) ζει στις ατόλλες και στα νησιά του αρχιπελάγους της Χαβάης και, όπως και ο στενός συγγενής της, η μεσογειακή φώκια, απειλείται άμεσα με αφανισμό.
Με το μακρόστενο σώμα τους, τον χονδρό, ευλύγιστο λαιμό, το κοντό και φαρδύ κεφάλι και τα κοντά πτερύγια μοιάζουν με όλες τις άλλες φώκιες και κυρίως με την μεσογειακή. Με μήκος μέχρι 2,40 μέτρα και βάρος 270 κιλά είναι λίγο μικρότερη από την τελευταία. Σε αντίθεση όμως με την μεσογειακή, τα θηλυκά της φώκιας της Χαβάης είναι μεγαλύτερα από τα αρσενικά, τα οποία φτάνουν τα 2,10 μέτρα και 200 κιλά. Είναι γκρίζες με καφέ στη ράχη ενώ στην κοιλιά πιο ανοιχτόχρωμες, χωρίς όμως το λευκό «μπάλωμα» της μεσογειακής φώκιας. Τα νεογέννητα έχουν μήκος περίπου 1 μέτρο και βάρος 15-18 κιλά και είναι καλυμμένα με μαύρη γούνα, η οποία αντικαθίσταται με κοντό τρίχωμα μετά από έξι εβδομάδες κατά την πρώτη έκδυση. Πολλές φορές οι φώκιες της Χαβάης φέρουν ορατά σημάδια και ουλές από αλιευτικά εργαλεία και επιθέσεις καρχαριών. Τα αισθητήρια μουστάκια στο ρύγχος είναι μαλακά και σκουρόχρωμα με λευκές απολήξεις, ενώ τα ρουθούνια της κοιτούν προς τα πάνω και όχι προς τα μπρος όπως στη μεσογειακή φώκια.[2][3]
Την βρίσκουμε στα λεγόμενα «Υπήνεμα Νησιά» του βορειοδυτικού αρχιπελάγους της Χαβάης. Εκτός αναπαραγωγικής περιόδου είναι μοναχικό ζώο, σε σχέση με τις άλλες φώκιες. Στις αμμουδερές τους παραλίες ξεκουράζεται και φέρνει στον κόσμο τα μικρά της. Τα 2/3 της ζωής της όμως τα περνάει μέσα στη θάλασσα. Πρόσφατες έρευνες έδειξαν πως, αντίθετα με παλαιότερες αντιλήψεις, περνούν αρκετό χρόνο για την τροφοσυλλογή τους σε μεγάλα βάθη πάνω από 160 οργιές (300 μέτρα), σε κάποιες περιπτώσεις ακόμη και 300 οργιές (550 μέτρα).[2][4][5] Συνήθως δεν απομακρύνονται από το αρχιπέλαγος, αν και έχουν εντοπιστεί μεμονωμένα ζώα στις ατόλλες Τζόνστον, Παλμύρα και Ουέηκ που απέχουν 1.150, 1.800 και 3.700 χιλιόμετρα από την Χαβάη αντίστοιχα. Το διαιτολόγιο της φώκιας της Χαβάης αποτελείται κυρίως από οστεϊχθύες (79%) αλλά και από κεφαλόποδα (16%) και καρκινοειδή (5%).[6]
Χαρακτηρίζεται ως κρισίμως κινδυνεύον με αφανισμό από την Διεθνή Ένωση Προστασίας της Φύσης. Υπολογίζεται πως έχουν απομείνει γύρω στα 1000 ζώα, αριθμός όμως που συνεχίζει να μειώνεται παρά τα μέτρα προστασίας που πάρθηκαν τις τελευταίες δεκαετίες. Η καταστροφή των βιοτόπων της, η υπεραλίευση και η καταδίωξη από τους ψαράδες είναι οι μεγαλύτερες απειλές για την επιβίωση της. Σε αυτές προστίθεται και η περιορισμένη γενετική ποικιλομορφία των εναπομεινάντων φωκών αλλά και οι φυσικοί εχθροί μέσα στην θάλασσα: ο καρχαρίας τίγρης και ο καρχαρίας των Γκαλαπάγκος. Αυτή η περιορισμένη γενετική ποικιλομορφία οφείλεται στην κατακόρυφη μείωση του πληθυσμού και είναι το αποτέλεσμα του ανελέητου κυνηγιού της φώκιας από τον άνθρωπο κατά τον 19ο αιώνα. Αυτό έχει σαν αποτέλεσμα την μειωμένη φυσική επιλογή και ικανότητα του είδους να προσαρμοστεί στις περιβαλλοντικές πιέσεις αυξάνοντας τον κίνδυνο του αφανισμού.[7]
|accessdate= (βοήθεια) |accessdate= (βοήθεια) Η φώκια μοναχός της Χαβάης (Monachus schauinslandi - Μοναχός του Σάουινσλαντ) ζει στις ατόλλες και στα νησιά του αρχιπελάγους της Χαβάης και, όπως και ο στενός συγγενής της, η μεσογειακή φώκια, απειλείται άμεσα με αφανισμό.
The Hawaiian monk seal (Neomonachus schauinslandi) is an endangered species of earless seal in the family Phocidae that is endemic to the Hawaiian Islands.[2]
The Hawaiian monk seal is one of two extant monk seal species; the other is the Mediterranean monk seal. A third species, the Caribbean monk seal, is extinct.[3]
The Hawaiian monk seal is the only seal native to Hawaii, and, along with the Hawaiian hoary bat, is one of only two mammals endemic to the islands.[4]
N. schauinslandi is a conservation reliant endangered species. The small population of about 1,400 individuals is threatened by human encroachment, very low levels of genetic variation, entanglement in fishing nets, marine debris, disease, and past commercial hunting for skins.[5][6] There are many methods of conservation biology when it comes to endangered species; translocation, captive care, habitat cleanup, and educating the public about the Hawaiian monk seal are some of the methods that can be employed.[7][8][9]
Known to native Hawaiians as ʻIlio-holo-i-ka-uaua, or "dog that runs in rough water", its scientific name is from Hugo Schauinsland, a German scientist who discovered a skull on Laysan Island in 1899.[10] Its common name comes from short hairs on its head, said to resemble a monk.[3] It is the official state mammal of Hawaii.[11]
Its grey coat, white belly, and slender physique distinguish them from their cousin, the harbor seal (Phoca vitulina).[3] The monk seal's physique is ideal for hunting its prey: fish, lobster, octopus and squid in deep water coral beds.[12] When it is not hunting and eating, it generally basks on the sandy beaches and volcanic rock of the Northwest Hawaiian Islands.[13]
The Hawaiian monk seal is part of the family Phocidae, being named so for its characteristic lack of external ears and inability to rotate its hind flippers under the body.[14] The Hawaiian monk seal has a relatively small, flat head with large black eyes, eight pairs of teeth, and short snouts with the nostril on top of the snout and vibrissae on each side.[3] The nostrils are small vertical slits which close when the seal dives underwater. Additionally, their slender, torpedo-shaped body and hind flippers allow them to be very agile swimmers.[15]
Adult males are 140 to 180 kilograms (300 to 400 pounds) in weight and 2.1 metres (7 feet) in length while adult females tend to be, on average, slightly larger, at 180 to 270 kg (400 to 600 lb) and 2.4 m (8 ft) in length. When monk seal pups are born, they average 14 to 18 kg (30 to 40 lb) and 1 m (40 in) in length. As they nurse for approximately six weeks, they grow considerably, eventually weighing between 70 and 90 kg (150 and 200 lb) by the time they are weaned, while the mother loses up to 140 kg (300 lb).
Monk seals, like elephant seals, shed their hair and the outer layer of their skin in an annual catastrophic molt. During the most active period of the molt, about 10 days for the Hawaiian monk seal,[16] the seal remains on the beach. The hair, generally dark gray on the dorsal side and lighter silver ventrally, gradually changes color through the year with exposure to atmospheric conditions. Sunlight and seawater cause the dark gray to become brown and the light silver to become yellow-brown, while long periods of time spent in the water can also promote algae growth, giving many seals a green tinge. The juvenile coat of the monk seal, manifest in a molt by the time a pup is weaned is silver-gray; pups are born with black pelage. Many Hawaiian monk seals sport scars from shark attacks or entanglements with fishing gear. Maximum life expectancy is 25 to 30 years.
The monk seals are members of the Phocidae. In an influential 1977 paper, Repenning and Ray proposed, based on certain unspecialized features, that they were the most primitive living seals.[17] However, this idea has since been entirely superseded.
In an effort to inform the public and conserve the seals, the National Oceanic Atmospheric Administration (NOAA) Fisheries Service developed a historical timeline to demonstrate that the Hawaiian islands has been home to the seals for millions of years and that the seals belong there. Evidence points to monk seals migrating to Hawaii between 4–11 million years ago (mya) through an open water passage between North and South America called the Central American Seaway. The Isthmus of Panama closed the Seaway approximately 3 million years ago.[18]
Berta and Sumich ask how this species came to the Hawaiian Islands when its closest relatives are on the other side of the world in the North Atlantic and Mediterranean Sea.[19] The species may have evolved in the Pacific or Atlantic, but in either case, came to Hawaii long before the first Polynesians.
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The majority of the Hawaiian monk seal population can be found around the Northwest Hawaiian Islands but a small and growing population lives around the main Hawaiian Islands.[13] These seals spend two-thirds of their time at sea. Monk seals spend much of their time foraging in deeper water outside of shallow lagoon reefs at sub-photic depths of 300 metres (160 fathoms) or more.[20][21] Hawaiian monk seals breed and haul-out on sand, corals, and volcanic rock; sandy beaches are more commonly used for pupping.[13] Due to the immense distance separating the Hawaiian Islands from other land masses capable of supporting the Hawaiian monk seal, its habitat is limited to the Hawaiian Islands.
Hawaiian monk seals mainly prey on reef dwelling bony fish, but they also prey on cephalopods, and crustaceans.[12] Both juveniles and sub-adults prey more on smaller octopus species, such as Octopus leteus and O. hawaiiensis, nocturnal octopus species, and eels than the adult Hawaiian monk seals,[12] while adult seals feed mostly on larger octopus species such as O. cyanea. Hawaiian monk seals have a broad and diverse diet due to foraging plasticity which allows them to be opportunistic predators that feed on a wide variety of available prey.[12]
Hawaiian monk seals can hold their breath for up to 20 minutes and dive more than 550 m (1,800 ft); however, they usually dive an average of 6 minutes to depths of less than 60 m (200 ft) to forage at the seafloor.[22]
Tiger sharks, great white sharks and Galapagos sharks are the main predators of the Hawaiian monk seal.[23]
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Hawaiian monk seals mate in the water during their breeding season, which occurs between June and August.[3] Females reach maturity at age four and give birth to one pup a year. The fetus takes nine months to develop, with birth occurring between March and June. Pups start around 16 kg (35 lb) and are about 1 m (3 ft 3 in) long.[24]
The pups are born on beaches and nursed for about six weeks. The mother does not eat or leave the pup while nursing. After that time, the mother deserts the pup, leaving it on its own, and returns to the sea to forage for the first time since the pup's arrival.[15]
Most seals are found on the Northwestern Hawaiian Islands.[25]
The Hawaiian monk seal is endangered,[26] although its cousin species, the Mediterranean monk seal (M. monachus), is even rarer, and the even more closely related Caribbean monk seal (N. tropicalis), last sighted in the 1950s, was officially declared extinct in June 2008.[27] In 2010, it was estimated that only 1100 individuals remained. A later estimate in 2016, which included a more complete survey of small populations, was approximately 1400 individuals.[5]
Seals nearly disappeared from the main islands, but the population has begun to recover. The growing population there was approximately 150 as of 2004[25] and 300 as of 2016.[5] Individuals have been sighted in surf breaks and on beaches in Kauaʻi, Niʻihau and Maui. Community volunteers on Oʻahu have made many anecdotal blog reports of sightings around the island since 2008. In early June 2010, two seals hauled out on Oʻahu's popular Waikiki beach. Seals have hauled out at O'ahu's Turtle Bay,[28] and again beached at Waikiki on March 4, 2011, by the Moana Hotel. Yet another adult came ashore for a rest next to the breakwater in Kapiolani Park Waikiki on the morning of December 11, 2012, after first being spotted traveling west along the reef break from the Aquarium side of the Park. On June 29, 2017 monk seal #RH58 popularly known as "Rocky" gave birth to a pup on Kaimana Beach fronting Kapiolani park. Despite the fact Kaimana beach is popular and busy, Rocky has been routinely hauling out on this beach for several years.[29] In 2006, twelve pups were born in the main islands, rising to thirteen in 2007, and eighteen in 2008. As of 2008 43 pups had been counted in the main islands.[30]
The Hawaiian monk seal was officially designated as an endangered species on November 23, 1976, and is now protected by the Endangered Species Act and the Marine Mammal Protection Act. It is illegal to kill, capture or harass a Hawaiian monk seal. Even with these protections, human activity along Hawaii's fragile coastlines (and in the world at large) still provides many stressors.[31]
Natural factors threatening the Hawaiian monk seal include low juvenile survival rates, reduction of habitat/prey associated with environmental changes, increased male aggression, and subsequent skewed gender ratios.[32] Anthropogenic or human impacts include hunting (during the 1800s and 1900s) and the resulting small gene pool, continuing human disturbance, entanglement in marine debris, and fishery interactions.[32]
Low juvenile survival rates continue to threaten the species. High juvenile mortality is due to starvation and marine debris entanglement.[8] Another contributor to the low juvenile survival rates is predation from sharks, including tiger sharks. Most mature monk seals bear scars from shark encounters, and many such attacks have been observed.[32]
Reduced prey abundance can lead to starvation, with one cause being reduction in habitat associated with environmental change.[32] Habitat is shrinking due to erosion in the Northwest Hawaiian Islands, reducing the size of islands/beaches.[32] Lobsters, the seals' preferred food other than fish, have been overfished. Competition from other predators such as sharks, jacks, and barracudas leaves little for developing pups. The creation of Papahānaumokuākea Marine National Monument which encloses these islands may expand food supplies.
Mobbing is a practice among the seals that involves multiple males attacking one female in mating attempts. Mobbing is responsible for many deaths, especially to females.[33]
Mobbing leaves the targeted individual with wounds that increase vulnerability to sepsis, killing the victim via infection.[33] Smaller populations were more likely to experience mobbing as a result of the higher male/female ratio and male aggression. Unbalanced sex-ratios were more likely to occur in slow-growing populations.[34][35]
Postmortem examinations of some seal carcasses revealed gastric ulcerations caused by parasites.[36] Some of the infectious diseases that pose a threat to the Hawaiian monk seal populations include distemper viruses, West Nile Virus, Leptospira spp., and Toxoplasma gondii.[37] Protozoal-related mortality,[38] specifically due to toxoplasmosis, are becoming a great threat to the recovery of the endangered Hawaiian monk seal and other native Hawaiian marine life.
In the nineteenth century, large numbers of seals were killed by whalers and sealers for meat, oil and skin.[39] U.S. military forces hunted them during World War II, while occupying Laysan Island and Midway.[39]
The Hawaiian monk seal has the lowest level of genetic variability among the 18 pinniped species.[8] This low genetic variability was allegedly due to a population bottleneck caused by intense hunting in the 19th century.[8] This limited genetic variability reduces the species ability to adapt to environmental pressures and limits natural selection, thus increasing their risk of extinction.[8] Given the monk seal's small population, the effects of disease could be disastrous.
Monk seals can be affected by the toxoplasmosis pathogen in cat feces that enters the ocean in polluted runoff and wastewater, a new phenomenon.[40] Since 2001, toxoplasmosis has killed at least eleven seals.[41] Other human-introduced pathogens, including leptospirosis, have infected monk seals.[40]
Human disturbances have had immense effects on the populations of the Hawaiian monk seal. Monk seals tend to avoid beaches where they are disturbed; after continual disturbance the seal may completely abandon the beach, thus reducing its habitat size, subsequently limiting population growth. For instance, large beach crowds and beach structures limit the seal's habitat.[7][32][40] Although the WWII military bases in the northwestern islands were closed, minimal human activities can be enough to disturb the species.[32]
Marine fisheries can potentially interact with monk seals via direct and indirect relationships. Directly the seal can become snared by fishing equipment, entangled in discarded debris, and even feed on fish refuse.[32] Although international law prohibits the intentional discarding of debris from ships at sea, entanglement still results in mortality because the seals get trapped in unintentional marine debris such as fishing nets and cannot maneuver or even reach the surface to breathe.[8] Monk seals have one of the highest documented rates of entanglement of any pinniped species.[32]
In 1909, President Theodore Roosevelt created the Hawaiian Islands Reservation that included the Northwest Hawaiian islands. The Reservation later became the Hawaiian Islands National Wildlife Refuge (HINWR) and moved under the jurisdiction of the U.S. Fish and Wildlife Service (USFWS).[32] Throughout the 1980s, the National Marine Fisheries Service completed various versions of an Environmental Impact Statement that designated the Northwest Hawaiian Islands as a critical habitat for the Hawaiian monk seal. The designation prohibited lobster fishing in waters less than 18 metres (10 fathoms) in the Northwest Hawaiian Islands and within 37 kilometres (20 nautical miles) of Laysan Island. The National Marine Fisheries Service designated all beach areas, lagoon waters, and ocean waters out to a depth of 18 m (10 fathoms) (later 37 m or 20 fathoms) around the Northwestern Hawaiian Islands, except for one of the Midway group, Sand Island. In 2006, a Presidential Proclamation established the Papahanaumokuakea Marine National Monument, which incorporated the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve, the Midway Atoll National Wildlife Refuge, the Hawaiian Islands National Wildlife Refuge, and the Battle of Midway National Memorial, thus creating the largest marine protected area in the world and affording the Hawaiian monk seal further protection.[42]
NOAA cultivated a network of volunteers to protect the seals while they bask or bear and nurse their young. NOAA is funding considerable research on seal population dynamics and health in conjunction with the Marine Mammal Center.
From NOAA, several programs and networks were formed to help the Hawaiian monk seal. Community programs such as PIRO have helped to improve community standards for the Hawaiian monk seal. The program also creates networks with the Native Hawaiians on the island to network more people in the fight for conservation of the seals. The Marine Mammal Response Network (MMRN) is partnered with NOAA and several other government agencies that deal with land and marine wildlife.[43]
The Recovery Plan for the Hawaiian Monk Seal identifies public outreach and education as a key action for promoting the conservation of the Hawaiian monk seal and its habitat.[42]
To raise awareness of the species' plight, on June 11, 2008, a state law designated the Hawaiian monk seal as Hawaii's official State Mammal .[44]
The task is to identify a manner of alleviation that is possible, cost-effective, and likely to maximize the organic return (in terms of growth potential) until much time has passed and natural conditions allow scientists to observe the effects.[32]
One key natural factor affecting the seal populations is the male-biased sex-ratio, which results in increased aggressive behaviors such as mobbing.[34] These aggressive behaviors decrease the number of females in the population. Two programs effectively aid female survival rates.
A headstarting project began in 1981, collecting and tagging female pups after weaning and placing them in a large, enclosed water and beach area with food and lacking disturbances.[45] The female pups remain during the summer months, leaving at roughly age three to seven months.
Another project began in 1984 at French Frigate Shoals. It collected severely underweight female pups, placed them in protective care, and fed them. The pups were relocated to Kure Atoll and released as yearlings.[45]
Some habitats are better suited to increase survival probability, making relocation a popular and promising method.[9] Although no direct links between infectious diseases and seal mortality rates have been found, unidentified infectious diseases could prove detrimental to relocation strategies.[46] Identification and mitigation of these and other possible factors limiting population growth represent ongoing challenges and are the primary objectives of the Hawaiian monk seal conservation and recovery effort.[36]
It is also important to consider the mothers who nurse their pups. Seal milk is very rich in nutrients, allowing pups to gain weight rapidly. With the rich milk from the mother, the pup is more likely to quadruple its initial weight before weaning. The mother seal also loses a tremendous amount of weight while nursing.[47]
In 2011, the National Marine Fisheries Service issued a controversial draft programmatic environmental impact statement intended to improve protections for the monk seal.[48] The plan includes:
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{{cite book}}: CS1 maint: unfit URL (link) The Hawaiian monk seal (Neomonachus schauinslandi) is an endangered species of earless seal in the family Phocidae that is endemic to the Hawaiian Islands.
The Hawaiian monk seal is one of two extant monk seal species; the other is the Mediterranean monk seal. A third species, the Caribbean monk seal, is extinct.
The Hawaiian monk seal is the only seal native to Hawaii, and, along with the Hawaiian hoary bat, is one of only two mammals endemic to the islands.
N. schauinslandi is a conservation reliant endangered species. The small population of about 1,400 individuals is threatened by human encroachment, very low levels of genetic variation, entanglement in fishing nets, marine debris, disease, and past commercial hunting for skins. There are many methods of conservation biology when it comes to endangered species; translocation, captive care, habitat cleanup, and educating the public about the Hawaiian monk seal are some of the methods that can be employed.
La Havaja monaĥfoko, Monachus schauinslandi, aŭ pli simple la Havaja foko estas fokulo apartenanta al la familio de Focedoj. Ĝi estas endanĝerita specio de foko kiu estas endemia de Havajo.[1]
La Havaja monaĥfoko estas unu el du restantaj monaĥfokaj specioj; dum la alia estas la Mediteranea monaĥfoko. Tria specio, nome la Kariba monaĥfoko, iĝis formortinta.
La Havaja monaĥfoko estas la ununura foko indiĝena de Havajo.[2]
Tiuj monaĥfokoj estas relikva endanĝerita specio. La malgranda populacio de ĉirkaŭ 1,100 individuoj estas minacata pro homa premado, tre malaltaj niveloj de genetika variado, interplektiĝo en fiŝretoj, mara rubo, malsanoj, kaj pasinta komerca ĉasado por feloj. Estas multaj metodoj por konservisma biologio kiam ĝi venas al statuso de endanĝerita specio; specitranslokigo, zorgado en kaptiteco, habitata purigado, kaj edukado al publiko pri la Havaja monaĥfoko estas el metodoj kiuj povas esti uzitaj.[3][4][5]
Havaja monaĥfoko La Havaja monaĥfoko, Monachus schauinslandi, aŭ pli simple la Havaja foko estas fokulo apartenanta al la familio de Focedoj. Ĝi estas endanĝerita specio de foko kiu estas endemia de Havajo.
La Havaja monaĥfoko estas unu el du restantaj monaĥfokaj specioj; dum la alia estas la Mediteranea monaĥfoko. Tria specio, nome la Kariba monaĥfoko, iĝis formortinta.
La Havaja monaĥfoko estas la ununura foko indiĝena de Havajo.
Tiuj monaĥfokoj estas relikva endanĝerita specio. La malgranda populacio de ĉirkaŭ 1,100 individuoj estas minacata pro homa premado, tre malaltaj niveloj de genetika variado, interplektiĝo en fiŝretoj, mara rubo, malsanoj, kaj pasinta komerca ĉasado por feloj. Estas multaj metodoj por konservisma biologio kiam ĝi venas al statuso de endanĝerita specio; specitranslokigo, zorgado en kaptiteco, habitata purigado, kaj edukado al publiko pri la Havaja monaĥfoko estas el metodoj kiuj povas esti uzitaj.
La foca monje de Hawái o foca fraile hawaiana (Neomonachus schauinslandi)[5] es un mamífero pinnípedo de la familia de los fócidos endémica, en peligro de extinción, que rodean las islas del noroeste del archipiélago de Hawái.
La foca monje de Hawái (descrita por primera vez en 1905[4]) es, junto con la foca monje del Mediterráneo (Monachus monachus) una de las dos únicas especies vivas de focas monje, actualmente agrupadas en géneros distintos.[3] Una tercera especie, foca monje del Caribe (N. tropicalis), se ha extinguido.[5]
Está especie es nativa, de las islas de Hawái.[6] La foca monje hawaiana está en peligro crítico, por culpa del gran número de desechos químicos que produce la pesca del norte del Océano Pacífico, en los arrecifes y playas.[7] Su dieta está constituida por peces, cefalópodos y crustáceos. Su periodo de vida es entre los 25 y 30 años.[5]
Al nacer los cachorros pesan 35 libras (16 kg). Su peso común es de 375 libras a 450 libras (170 a 205 kg), las hembras son de mayor tamaño que los machos. La cola mide entre los 2.1 metros a 2.3 metros, la de los cachorros miden 1 metro. Son de color gris plateado en la parte superior, y la parte inferior son de un color crema claro; cuando nacen que poseen un color. La parte posterior de los animales se puede oscurecer a través del tiempo, especialmente en los machos.[5]
La foca monje de Hawái o foca fraile hawaiana (Neomonachus schauinslandi) es un mamífero pinnípedo de la familia de los fócidos endémica, en peligro de extinción, que rodean las islas del noroeste del archipiélago de Hawái.
La foca monje de Hawái (descrita por primera vez en 1905) es, junto con la foca monje del Mediterráneo (Monachus monachus) una de las dos únicas especies vivas de focas monje, actualmente agrupadas en géneros distintos. Una tercera especie, foca monje del Caribe (N. tropicalis), se ha extinguido.
Está especie es nativa, de las islas de Hawái. La foca monje hawaiana está en peligro crítico, por culpa del gran número de desechos químicos que produce la pesca del norte del Océano Pacífico, en los arrecifes y playas. Su dieta está constituida por peces, cefalópodos y crustáceos. Su periodo de vida es entre los 25 y 30 años.
Monachus schauinslandi Monachus generoko animalia da. Artiodaktiloen barruko Phocidae familian sailkatuta dago..
Monachus schauinslandi Monachus generoko animalia da. Artiodaktiloen barruko Phocidae familian sailkatuta dago..
Havaijinhylje (Monachus schauinslandi) on erittäin uhanalainen hyljelaji, jota voi tavata Havaijin saaristossa. Se on nykyisin ainoa tropiikissa elävä hylje.
Havaijinhylje on 2–2,3 metrin pituinen ja painaa 200–300 kiloa, lajin naaraat ovat uroksia kookkaampia. Havaijinhylkeiden selkä on tummanharmaa ja vatsa vaaleankellertävä.
Havaijinhyljettä tavataan vain Luoteis-Havaijilla. Niitä tavataan French Frigate Shoalsilla, Laysanilla, Lisianskilla, Pearl- ja Hermes-riutalla, Midweyn atollilla ja Kuren Atollilla. Pieniä populaatioita on myös Neckerillä ja Nihoalla. Hylkeet lepäävät autioilla rannoilla, mutta hankkivat ravintonsa saarten ulkopuolelta avoimelta merenpohjalta, jopa 500 metrin syvyydestä.
Havaijinhylkeet elävät yksikseen. Aikuiset pitävät toisiinsa kohtuullisen välimatkan. Vain nuoret hylkeet leikkivät usein keskenään. Häirittyinä ne päästävät kurluttavia ääniä, esimerkiksi uhkaillessaan lajitoveriaan. Ihmistä laji yleensä kaihtaa. Hylkeet viettävät jopa viikkoja merellä etsimässä ravintoa avoimilta syvänteiltä. Ne eivät yleensä välitä riuttojen kaloista ehkä siksi, että kaloja on vaikea napata niiden piiloutuessa riutan suojiin. Sen sijaan riuttojen ulkopuolella hylkeet voivat etsiä kivien alta kaloja, äyriäisiä piikkinahkaisia ja nilviäisiä. Laji myös ruokailee 500 metrin syvyydessä sijaitsevilla pienillä riutoilla, joilla niillä ei ole kilpailijoita.
Keväällä urokset kiertelevät saaria naaraita etsien. Parittelu tapahtuu vedessä. Poikasia syntyy eniten maalis-toukokuussa. Poikanen syntyy yleensä hiekkarannalla, joskus rantakalliolla. Emo imettää kuuttia kuusi viikkoa, eikä naaras poistu poikasen luota tänä aikana. Emon on siis pakko paastota ja se menettääkin painoa kaksi kiloa yhtä poikasen kiloa kohden. Poikanen lähtee pian vieroittamisen jälkeen merelle hankkimaan itse ruokansa. Kokematon poikanen jää usein erityisesti tiikerihain saaliiksi.
Havaijinhylkeitä on nykyään noin 1 300–1 400 yksilöä ja kanta on toipunut 500 yksilön aallonpohjasta hyvin. Eniten niitä on French Frigate Shoalsilla, jossa elää 400 hyljettä. Hylkeet ovat kärsineet etenkin häirinnästä ja lisääntyminen on epäonnistunut usein. Midwaysaarten hylkeet kärsivät ihmisasutuksesta, kun saarelle perustettiin sotilastukikohta toisen maailmansodan jälkeen. Hylkeet vähitellen hävisivät saarilta vuoteen 1968 mennessä. Ne palasivat vasta, kun sotilastukikohta lakkautettiin 1990-luvulla ja saarista tuli luonnonsuojelualue. Midwayn hyljekanta on kasvanut noin kuuteenkymmeneen. Kuren atolli on nykyään ainoa, jolla asutus haittaa hylkeitä. Myös ajelehtiviin verkkoihin hukkuu paljon uteliaita hylkeitä. Vuonna 2006 Havaijien saaristoon perustettiin erittäin laaja suojelualue.
Havaijinhylje (Monachus schauinslandi) on erittäin uhanalainen hyljelaji, jota voi tavata Havaijin saaristossa. Se on nykyisin ainoa tropiikissa elävä hylje.
Phoque moine d'Hawaï
Monachus schauinslandi, communément appelé le Phoque moine d'Hawaï[3], est une espèce de phoques endémique de l'archipel d'Hawaï.
L'espèce Monachus schauinslandi a été décrite en 1905 par le zoologiste allemand Paul Matschie (1861-1926)[4].
Pour l’ITIS et BioLib cette espèce doit désormais être rangée dans le genre Neomonachus, sous le taxon Neomonachus schauinslandi (Matschie, 1905)[5],[2].
La femelle est plus grande que le mâle, elle mesure en moyenne 2,25 m de long pour un poids de 203 kg. Le mâle mesure 2,10 m de long pour 169 kg[6].
C'est la seule espèce de phoques habitant les tropiques et ne présentant aucune adaptation anatomique pour vivre dans ces eaux chaudes. Cette espèce semble tout de même s'être adaptée au climat tropical en demeurant inactif durant la journée[7].
Depuis des centaines d'années, l'homme est la plus grande menace du phoque moine d'Hawaï. Ils ont probablement été extirpés des principales îles hawaïennes par les colonisateurs polynésiens il y a de cela 1 500 à 1 600 ans. Au XIXe siècle, à l'arrivée des premiers marins européens, le phoque moine hawaïen a été chassé jusqu'à près de l'extinction vers la fin du siècle dans les six populations principales des îles du nord-ouest (Bancs des Frégates françaises, Laysan, Lisianski, les récifs Pearl et Hermes, Atolls Midway et Kure). Ils étaient activement chassés pour leur chair et leur fourrure[8].
Ces baisses épisodiques dans la population de phoques moines d'Hawaï ont entraîné une diminution considérable de la variabilité génétique chez l'espèce, ce qui la rend encore plus vulnérable face à toute menace. De plus, les femelles et les petits sont extrêmement sensibles aux perturbations[9]. Selon les plus récentes estimations d'abondance totale, on compte près de 1247 phoques moines[10].
En dépit d'une bonne corrélation entre la productivité en surface des océans (production de phytoplanctons), le phoque moine d'Hawaï s'alimente des diverses espèces de poissons, d'espèces benthiques ainsi que d'invertébrés habitant les récifs de l'archipel hawaïen[11].
De récentes études ont démontré un changement dans le comportement de ces phoques au sujet de leur quête alimentaire. En effet, au lieu de chasser un vaste choix de proies habitant les récifs coralliens, ils optent plutôt pour des proies vivant en profondeur dans les zones méso et subphotiques et ce, à plusieurs kilomètres de leurs lieux de repos[12]. La principale raison à savoir pourquoi ces phoques risquent à s'alimenter plus en profondeur est que les proies sont beaucoup plus exposées aux prédateurs comparativement à ceux habitant les coraux, qui leur fournissent une plus grande possibilité de cachettes. Les plongées les plus profondes faites par les phoques ont été enregistrées à plus de 500 m[11].
La saison de reproduction s'étend de mars à août avec un pic d'activité en avril. La femelle donne naissance à un seul petit après une période de gestation de 11 mois. La longévité est de 25 à 30 ans dans la nature[6].
Son épithète spécifique, schauinslandi, lui a été donnée en l'honneur du zoologiste allemand Hugo Hermann Schauinsland (d) (1857-1937), directeur de l'Übersee-Museum (d) à Brême, qui avait rapporté cette espèce lors d'un voyage[4].
Phoque moine d'Hawaï
Monachus schauinslandi, communément appelé le Phoque moine d'Hawaï, est une espèce de phoques endémique de l'archipel d'Hawaï.
Havajska morska medvjedica (lat. Monachus schauinslandi) je kritično ugrožena vrsta perajara, ali i jedan od najugroženijih sisavaca na svijetu, koja je endemična i živi samo na Havajskom otočju, gdje je i jedina vrsta tuljana, te zapadno od njega u morskom području Papahānaumokuākea[1]. Pripada porodici pravih tuljana (Phocidae), te je jedna od samo dvije vrste iz roda Monachus („monaha”[2]) kojemu pripada i sredozemna medvjedica[3].
Havajski naziv za ovu životinju je ʻIlio-holo-i-ka-uaua („pas koji trči kroz vodu”).
Mala populacija od oko 1.100 jedinki je jako ugrožena ljudskim djelovanjem, ograničenim genetičkim materijalom i bolestima. Zbog toga je predmetom aktivne biološke zaštite koja podrazumijeva preseljenja jedinki, brigu u zatočeništvu, čišćenje habitata i obrazovanje javnosti o ovoj vrsti[4]
Veličinom je vrlo sličan običnom tuljanu od kojega se razlikuje svjetlijim krznom i bijelim stomakom, te vitkijom linijom. Težina im može biti sve do 270 kg, pri čemu su ženke nešto manje i lakše. Glava im je okrugla i plošna s velikim crnim očima na kratkom i debelom vratu. Vretenasto tijelo s debelim potkožnim slojem masti je prilagođeno za život u vodi. Prednji udovi su prilagođeni za kretanje u vodi, jer su prsti povezani plivaćom kožicom, a nokti su zakržljali. Stražnji udovi su potisnuti uz tijelo i služe pri plivanju kao repne peraje. Havajska medvjedica hrani se ribama, rakovima i mekušcima koje hvata oštrim zubima. Oko ustiju ima dugačke osjetilne dlake. Vid im je slabo razvijen, ali imaju dobro razvije sluh i njuh. Pretežito je noćna životinja. Prilikom zarona zatvara nosne i ušne otvore, a pod vodom može izdržati nekoliko minuta.
Na kopno izlazi radi odmora i parenja, kada zna provesti i do 10 dana u priobalnim vodama u području pustih i ne naseljenih otoka.
Havajska medvjedica se koti sa oko 100 cm dužine, a kad odrastu, mogu doseći dužinu oko 2,4 metra. Mladunci se kote u proljeće, a majke ih doje do starosti od oko 6 tjedana, do kada značajno narastu do 90 kg. Spolno zreli postaju u dobi od četiri godine, a očekivani životni vijek im je od 25 do 30 godina, ukoliko ne postanu plijenom mnogim grabežljivcima (uglavnom morski pas tigar i galapagoški morski pas). Skotna ženka havajske medvjedice za koćenje i podizanje mladunca traži otvorene plaže i ne napušta mladunče tijekom cijelih 6 tjedana dojenja, čak niti kako bi jela. Nakon toga trajno napušta mladunče koje se počinje samo brinuti o sebi.
U Wikimedijinu spremniku nalazi se članak na temu: Havajska morska medvjedica
Wikivrste imaju podatke o: Havajska morska medvjedica Havajska morska medvjedica (lat. Monachus schauinslandi) je kritično ugrožena vrsta perajara, ali i jedan od najugroženijih sisavaca na svijetu, koja je endemična i živi samo na Havajskom otočju, gdje je i jedina vrsta tuljana, te zapadno od njega u morskom području Papahānaumokuākea. Pripada porodici pravih tuljana (Phocidae), te je jedna od samo dvije vrste iz roda Monachus („monaha”) kojemu pripada i sredozemna medvjedica.
Havajski naziv za ovu životinju je ʻIlio-holo-i-ka-uaua („pas koji trči kroz vodu”).
Mala populacija od oko 1.100 jedinki je jako ugrožena ljudskim djelovanjem, ograničenim genetičkim materijalom i bolestima. Zbog toga je predmetom aktivne biološke zaštite koja podrazumijeva preseljenja jedinki, brigu u zatočeništvu, čišćenje habitata i obrazovanje javnosti o ovoj vrsti
Anjing laut hawaii adalah satwa liar yang terancam punah dan salah satu dari hanya dua mamalia yang endemik yang berasal dari Kepulauan Hawaii. Mamalia laut dari keluarga Phocidae ini, jumlah populasinya memakin berkurang dan diperkirakan tinggal 1.400 individu saja. Anjing laut hawaii terancam akibat diburu oleh manusia untuk diambil kulitnya, terjerat jaring ikan, terkena penyakit dan juga karena tingkat variasi genetik yang sangat rendah.
Anjing laut Hawaii adalah mamalia laut yang dilindungi di Negara bagian Hawaii. Penduduk asli Hawaii mengenal satwa ini dengan nama ʻIlio-holo-i-ka-uaua’ yang artinya anjing yang berenang atau berjalan di air yang deras. Hugo Schauinsland, seorang ilmuwan dari jerman yang memberikan nama ilmiah jenis ini setelah menemukan tengkoraknya di Pulau Laysan pada tahun 1899.[1]
Anjing laut hawaii adalah satwa liar yang terancam punah dan salah satu dari hanya dua mamalia yang endemik yang berasal dari Kepulauan Hawaii. Mamalia laut dari keluarga Phocidae ini, jumlah populasinya memakin berkurang dan diperkirakan tinggal 1.400 individu saja. Anjing laut hawaii terancam akibat diburu oleh manusia untuk diambil kulitnya, terjerat jaring ikan, terkena penyakit dan juga karena tingkat variasi genetik yang sangat rendah.
La foca monaca delle Hawaii (Neomonachus schauinslandi Matschie, 1905) è un mammifero della famiglia delle foche, endemico delle acque al largo delle isole hawaiane[1]. È una specie in pericolo di estinzione[2].
Nota ai nativi hawaiani come `Ilio-holo-i-ka-uaua, o «cane che corre in acque agitate», ricevette il suo nome scientifico, Monachus schauinslandi, dopo che il Dr. H. Schauinsland fece conoscere questa specie alla scienza, riportando con sé dall'isola di Laysan un cranio di questo animale. Il nome comune si deve alla testa rotonda ricoperta da piccoli peli che le dà l'aspetto di un frate medievale. Il nome riflette inoltre la caratteristica tendenza di quest'animale a trascorrere un'esistenza più solitaria rispetto alle altre foche, le quali si radunano in grandi colonie. Le foche monache hawaiane sono i membri viventi più primitivi della famiglia dei Focidi, essendosi separate dagli altri membri del gruppo circa 15 milioni di anni fa.
Le foche monache hawaiane adulte presentano un pelame, o mantello, di colore grigio, ma in alcuni casi può assumere una tonalità bruna. I giovani sono di colore argentato, con il ventre, il petto e la gola color bianco crema. I cuccioli sono ricoperti da una lanugine nera formata da brevi peli crespi. I neonati sono avvolti dalla nera pelliccia neonatale. Un gran numero di foche monache hawaiane presenta cicatrici causate da squali o da vari attrezzi da pesca. Comunque, la maggior parte delle ferite presenti sul corpo delle femmine sono dovute agli incontri con i maschi, che divengono particolarmente brutali durante la stagione riproduttiva. I maschi adulti pesano tra i 136 e i 181 chilogrammi e misurano 2,1 metri di lunghezza, mentre le femmine tendono a pesare tra i 181 e i 272 chilogrammi e a misurare 2,4 metri. I cuccioli pesano alla nascita tra i 13 e i 18 chilogrammi e misurano 101 centimetri di lunghezza. Questa specie vive tra i 25 e i 30 anni.
La foca monaca delle Hawaii vive nelle isole hawaiane nord-occidentali (NWHI) e occasionalmente è stata avvistata anche attorno alle isole maggiori. In occasioni rarissime, qualche esemplare si è tratto anche sulla riva di isole più popolose. Avvistamenti regolari sono avvenuti a Ho'okipa, su Maui, e a Poipu, su Kaua'i. La popolazione più numerosa (circa 1500 esemplari nel 2002) si trova sui Banchi di French Frigate.
Queste foche si portano sulle spiagge sabbiose per riposarsi, per riprodursi e forse, nelle NWHI, per sfuggire agli attacchi degli squali. Sulla terra la respirazione viene effettuata attraverso lunghe inspirazioni. Le foche monache sono solitarie, sia in acqua che a riva. Sulle spiagge si radunano sparuti gruppetti solo quando le condizioni ambientali sono favorevoli. A eccezione delle madri con i piccoli, quando riposano queste foche evitano ogni contatto con i conspecifici.
Le foche monache hawaiane si nutrono di aragoste spinose, anguille, pesci piatti, scorpenidi, avannotti e polpi[3]. In un giorno possono ingurgitare una quantità di cibo pari al dieci per cento del loro peso corporeo. Talvolta, prima di ritornare sulle isole per riposare e per digerire, trascorrono parecchi giorni in mare.
Gli adulti sono in grado di immergersi a notevole profondità. Alcuni ricercatori dell'Università delle Hawaii hanno recentemente avvistato una foca monaca che nuotava tranquillamente a 542 metri sotto la superficie. Le testimonianze precedenti indicavano che queste foche non si spingessero oltre i 304 metri.
La foca monaca hawaiana è una delle foche più minacciate, insieme alle sue strette cugine, la foca monaca mediterranea (M. monachus), perfino più rara, e la foca monaca caraibica (N. tropicalis), il cui ultimo avvistamento risale agli anni '50 e che è stata dichiarata ufficialmente estinta nel giugno 2008[4]. La popolazione della specie hawaiana continua a declinare e, nel 2008, ne rimanevano solo 1200 esemplari[5]. Venne dichiarata ufficialmente minacciata il 23 novembre 1976 ed è ora protetta dall'Endangered Species Act e dal Marine Mammal Protection Act. Uccidere, catturare o disturbare uno di questi animali è illegale.
La IUCN red list classificava Neomonachus schauinslandi come specie in pericolo critico di estinzione (Critically Endangered), ma nel maggio del 2015 ha cambiato la sua classificazione catalogando la specie come in pericolo (Endangered)[2].
Per sensibilizzare quest'animale agli occhi dell'opinione pubblica, l'11 giugno 2008 il Vicegovernatore James Aiona ha dichiarato la foca monaca Mammifero di Stato delle Hawaii[6].
Quest'animale ha mostrato allarmanti diminuzioni nel corso degli anni recenti a causa della rapida diffusione delle attività umane perfino sulle più remote e isolate aree delle Hawaii. Nel diciannovesimo secolo queste foche venivano cacciate dai balenieri e dai cacciatori di foche per la carne, per l'olio e per le pelli. Venivano cacciate perfino durante la Seconda guerra mondiale, quando le forze statunitensi occuparono l'isola di Laysan e le Midway.[7]
Catture da parte degli squali, calo del tasso di sopravvivenza dei piccoli in seguito ai disturbi provocati dall'uomo, avvelenamenti da ciguatera, uccisioni di femmine da parte dei maschi durante la stagione riproduttiva e intrappolamenti nelle reti da pesca: tutto questo ha portato al declino della specie, che è scomparsa recentemente da molte parti del suo antico areale, comprese Oahu, Kaua'i e Hawaii. Attualmente vive solo a Laysan, sulle Midway, nell'Atollo di Pearl and Hermes, sui Banchi di French Frigate e sull'isola Lisianski.[7]
Nelle aree dove il numero dei maschi supera quello delle femmine, queste vengono contese fra i vari pretendenti, provocando spesso la morte di queste ultime. Spinti dal testosterone i maschi possono attaccare femmine di ogni età e perfino i piccoli. Tale comportamento, noto come «mobbing», è uno dei principali fattori di declino delle popolazioni[8].
Attualmente tale specie è sotto gli studi della National Oceanic and Atmospheric Administration statunitense e del Marine Mammal Center. Questi sforzi di conservazione sono diretti soprattutto a sensibilizzare la specie agli occhi della popolazione.
La foca monaca delle Hawaii (Neomonachus schauinslandi Matschie, 1905) è un mammifero della famiglia delle foche, endemico delle acque al largo delle isole hawaiane. È una specie in pericolo di estinzione.
Nota ai nativi hawaiani come `Ilio-holo-i-ka-uaua, o «cane che corre in acque agitate», ricevette il suo nome scientifico, Monachus schauinslandi, dopo che il Dr. H. Schauinsland fece conoscere questa specie alla scienza, riportando con sé dall'isola di Laysan un cranio di questo animale. Il nome comune si deve alla testa rotonda ricoperta da piccoli peli che le dà l'aspetto di un frate medievale. Il nome riflette inoltre la caratteristica tendenza di quest'animale a trascorrere un'esistenza più solitaria rispetto alle altre foche, le quali si radunano in grandi colonie. Le foche monache hawaiane sono i membri viventi più primitivi della famiglia dei Focidi, essendosi separate dagli altri membri del gruppo circa 15 milioni di anni fa.
Havajinis ruonis vienuolis (lot. Monachus schauinslandi, angl. Hawaiian monk seal) – šie ruoniai paplitę šiaurės vakarų Havajų negyvenamose salose. Minta priedugnės ir rifuose gyvenančiomis žuvimis. Patinai sveria nuo 180 kg iki 270 kg, o patelės būna šiek tiek didesnės.
Šis su teriologija susijęs straipsnis yra nebaigtas. Jūs galite prisidėti prie Vikipedijos papildydami šį straipsnį. Havajinis ruonis vienuolis (lot. Monachus schauinslandi, angl. Hawaiian monk seal) – šie ruoniai paplitę šiaurės vakarų Havajų negyvenamose salose. Minta priedugnės ir rifuose gyvenančiomis žuvimis. Patinai sveria nuo 180 kg iki 270 kg, o patelės būna šiek tiek didesnės.
De Hawaïaanse monniksrob (Monachus schauinslandi) is een zeehond uit het geslacht Monachus. De soort komt endemisch voor in Hawaï.[2] De soort staat bekend bij de inheemse Hawaïanen als Ilio-holo-i-ka-uaua, of "hond die loopt in ruw water".
De Hawaïaanse monniksrob is een bedreigde diersoort.
De Hawaïaanse monniksrob heeft een vacht die een grijze bruine kleur heeft. De jongen worden pups genoemd en zijn zilverachtig grijs van kleur met een witte buik, borst en keel. Pups zijn gekleed in een zwarte vacht. Veel exemplaren dragen de littekens van aanvallen van haaien of verwondingen van vistuig. Vrouwtjes zijn vaak getekend door paringspogingen; de mannetjes kunnen bijzonder agressief zijn voorafgaand aan de paring. De vrouwtjes worden groter dan de mannetjes. Volwassen mannetjes wegen 140 tot 180 kilogram en bereiken een lichaamslengte tot 2,1 meter. Volwassen vrouwen worden ongeveer 180 tot 270 kg zwaar en kunnen tot 2,4 m lang worden. Pups wegen gemiddeld 14 tot 18 kg en meten bij de geboorte 1,0 m in de lengte. De levensverwachting van de Hawaïaanse monniksrob in het wild bedraagt 25 tot 30 jaar.
Populaties van de Hawaïaanse monniksrob zijn in de afgelopen jaren als gevolg van de snelle verspreiding van menselijke activiteiten op zelfs de meest afgelegen en geïsoleerde Hawaïaanse eilanden afgenomen. In de negentiende eeuw werden Hawaïaanse monniksrobben doodgeknuppeld door walvisvaarders en zeehondenjagers voor hun vlees, olie en huid.[3] Amerikaanse troepen jaagden op hen tijdens de Tweede Wereldoorlog terwijl ze Laysan en Midway bezetten.[3]
Aanvallen door haaien zoals de tijgerhaai verkleinen de overlevingskans van jonge monniksrobben. De dieren hebben ernstig te leiden van menselijke verstoringen zoals ciguatera-vergiftiging, hoge man-vrouw verhoudingen tijdens het broedseizoen en verstrikking in visnetten en puin. In het noordwesten van Hawaïaanse eilanden is honger een ernstig probleem. Het favoriete voedsel van de zeehond bestaat uit kreeften en deze prooidieren worden overbevist door de mens. Door concurrentie van andere predatoren zoals haaien, horsmakrelen en barracuda's is er weinig ruimte over voor de ontwikkeling van de jonge monniksrobben. De oprichting van het Papahānaumokuākea Marine National Monument, dat toegevoegd werd tot deze eilanden, kan leiden tot meer overvloedige voedselvoorraden.
In gebieden waar de mannelijke zeehonden talrijker zijn dan de vrouwtjes, concurreren meerdere mannetjes voor een enkele vrouw, bekend als pesten, wat vaak het per ongeluk doden van de vrouw tot gevolg heeft. Vrouwen van alle leeftijden waaronder pups worden hieraan blootgesleld.[4]
Al deze bedreigingen hebben een tol op de soort. Zo is de soort bijna uitgeroeid op de belangrijkste eilanden van Hawaï.[5] Ze komen momenteel nog voor op Laysan, Midway, Pearl en Hermes Atol, French Frigate Shoals en Lisianski.[5]
Langzaam zijn de monniksrobben teruggekeerd naar de Hawaï-eilanden. Enkele zeehonden zijn gesignaleerd in de branding op het strand in Kauai, Niihau, Maui en Oahu Turtle Bay[6] en een aantal van de andere eilanden. Ze verlaten vaak het water op drukke toeristische stranden, waar ze kwetsbaar zijn voor verstoring. NOAA heeft een netwerk van vrijwilligers opgezet die de zeehonden beschermen, terwijl ze zonnen of hun jongen verzorgen. In 2006 werden twaalf pups geboren in de belangrijkste Hawaïaanse eilanden, oplopend tot dertien in 2007, en achttien in 2008.
NOAA financiert een deel van het onderzoek op het gebied van zeehondenpopulatie, dynamiek en gezondheid in samenhang met het Marine Mammal Center.
De Hawaïaanse monniksrob is een van de meest bedreigde soorten zeehonden, hoewel de verwante soort Mediterrane monniksrob (Monachus monachus) nog zeldzamer is. De Caribische monniksrob (Monachus tropicalis), laatst gezien in de jaren 1950, werd officieel uitgestorven verklaard in juni 2008.[7] De populatie van de Hawaïaanse monniksrob is in verval. In 2008 werd de populatie geschat op slechts 1200 individuen.[8] De Hawaïaanse monniksrob werd officieel als bedreigde diersoort aangeduid op 23 november 1976. De soort wordt nu beschermd door de Endangered Species Act en de Marine Mammal Protection Act.
Hoewel de eilanden waarop de Hawaïaanse monniksrob leeft worden beschermd, geloven veel wetenschappers dat de effecten van menselijke activiteiten langs deze kwetsbare kusten (en in de wereld in het algemeen) nog steeds hun tol eisen.[9]
Het is verboden om een Hawaïaanse monniksrob te doden, vangen of lastig te vallen.
Om de bewustwording voor aan te kaarten van de benarde situatie, werd het Hawaïaanse monniksrob aangeduid tot officiële zoogdier van de staat Hawaï op 11 juni 2008 door luitenant-gouverneur James Aiona.
De wetenschappelijke naam van de Hawaïaanse monniksrob Monachus schauinslandi bestaat uit twee delen en de laatste is de soortnaam; schauinslandi is een eerbetoon aan de wetenschapper Hugo Schauinsland die als eerste een eerste schedel van het dier vond op Laysan. De geslachtsnaam Monachus is afgeleid uit het Latijn en betekent 'op een monnik gelijkend'.
Deze naam slaat op het zijn ronde hoofd dat is bedekt met korte haren, waardoor het lijkt iets weg heeft van het kapsel van een middeleeuwse monnik. De naam kan ook verband houden met het feit dat het dier solitair leeft in vergelijking met andere zeehonden die zich verzamelen in grote kolonies.
Monniksrobben zijn de oudst bekende levende vertegenwoordigers van de familie Phocidae.
Bronnen, noten en/of referentiesDe Hawaïaanse monniksrob (Monachus schauinslandi) is een zeehond uit het geslacht Monachus. De soort komt endemisch voor in Hawaï. De soort staat bekend bij de inheemse Hawaïanen als Ilio-holo-i-ka-uaua, of "hond die loopt in ruw water".
De Hawaïaanse monniksrob is een bedreigde diersoort.
Hawaiimunkesel (Monachus schauinslandi) er en av to nålevende arter i slekten munkeseler (Monachus), som hører hjemme i selfamilien (Phocidae). Arten er ifølge IUCNs rødliste kritisk truet av utryddelse.[1] Totalbestanden teller trolig færre enn 1 100 dyr. Arten er stedegen for Hawaii.
Hannene blir omkring 2,1 m lange og veier typisk omkring 140–180 kg i snitt. Hunnene, som blir noe større, blir omkring 2,4 m lange og veier typisk omkring 180–270 kg. Pelsen er mørk stålgrå på oversiden og lysere grå i buken. Den kan variere noe i farge etter årstiden, gjennom å bli mer gråbrun til tider.
Hawaiimunkeselen eter helst beinfisker, men den kan også ernære seg av blekkspruter og krepsdyr. Det er kjent at arten leter etter mat på dybder ned mot 300 m eller mer utenfor korallrevene. Når arten ikke eter hviler den gjerne på strendene eller de vulkanske klippene ved havet.
ringsel (Pusa hispida)
bajkalsel (Pusa sibirica)
kaspisel (Pusa caspica)
flekksel (Phoca largha)
steinkobbe (Phoca vitulina)
havert (Halichoerus grypus)
harlekinsel (Histriophoca fasciata)
grønlandssel (Pagophilus groenlandicus)
klappmyss (Cystophora cristata)
storkobbe (Erignathus barbatus)
weddellsel (Leptonychotes weddellii)
leopardsel (Hydrurga leptonyx)
krabbeetersel (Lobodon carcinophagus)
ross-sel (Ommatophoca rossii)
sydlig sjøelefant (Mirounga leonina)
nordlig sjøelefant (Mirounga angustirostris)
middelhavsmunkesel (Monachus monachus)
hawaiimunkesel (Monachus schauinslandi)
Kladogrammet over viser slektskapet mellom de eksisterende artene i selfamilien.[2]
Hawaiimunkesel (Monachus schauinslandi) er en av to nålevende arter i slekten munkeseler (Monachus), som hører hjemme i selfamilien (Phocidae). Arten er ifølge IUCNs rødliste kritisk truet av utryddelse. Totalbestanden teller trolig færre enn 1 100 dyr. Arten er stedegen for Hawaii.
Multimedia w Wikimedia Commons Mniszka hawajska[3] (Neomonachus schauinslandi) - gatunek ssaka płetwonogiego z rodziny fokowatych (Phocidae).
Na podstawie badań molekularnych i biologicznych taksony M. schauinslandi i M. tropicalis umieszczono w rodzaju Neomonachus; drogi rozwojowe Monachus i Neomonachus rozeszły się w miocenie około 6,3 mln lat temu, zaś drogi rozwojowe M. schauinslandi i M. tropicalis w pliocenie, 3,67 mln lat temu[4].
Północno-zachodnia część Archipelagu Hawajskiego[5].
Opis: Osiąga długość ciała 183–240 cm; masa ciała 136–272 kg; samica jest nieco większa i cięższa od samca[6]. Skóra ubarwiona na szaro lub brunatno, na brzuchu jaśniejsza. Samiec jest ciemniejszy od samicy; noworodki pokryte są czarną skórą i wełnistą sierścią.
Środowisko życia: Laguny i strefy wody płytkiej wokół atoli. Żyją także na otwartym morzu. Młode zazwyczaj wychowywane są na piaszczystych plażach.
Pożywienie: ryby, skorupiaki i głowonogi.
Struktura społeczna: Przeżywają życie samotnie, brak trwałych struktur między osobnikami obu płci.
Rozwój: Okres rozrodczy u tych fok trwa od lutego do listopada. Po kopulacji, samica jest w ciąży przez około 10,5 miesiąca. Zazwyczaj rodzi jedno młode, choć czasami zdarzają się porody bliźniacze. Masa ciała noworodka waha się w przedziale 16-18 kg. Dojrzałość płciową samce osiągają w wieku 5 lat, natomiast samice w wieku 7 lat. Dożywają do 30 lat.
Gatunek krytycznie zagrożony wymarciem[2]. W latach 70, XX wieku, gdy stan populacji spadł do 500-600 zwierząt podjęto działania w celu zachowania gatunku. Obecnie populacja w przybliżeniu liczy 1750 osobników.
Mniszka hawajska (Neomonachus schauinslandi) - gatunek ssaka płetwonogiego z rodziny fokowatych (Phocidae).
A foca-monge-do-havaí (Monachus schauinslandi) é um mamífero pinípede habitante das águas quentes do arquipélago havaiano.
Hawaiis munksäl (Monachus schauinslandi) är en utrotningshotad sälart som förekommer endemiskt kring Hawaii.
Epitet, schauinslandi, i det vetenskapliga namnet syftar på den tyska zoologen Hugo Schauinsland som hittade den första skallen på ön Laysan.
Vuxna hannar når en vikt mellan 140 och 180 kg samt en längd upp till 2,1 m. Honor är vanligen tydlig större med en vikt mellan 180 och 270 kg samt en längd upp till 2,4 m. Arten föredrar sandiga stränder med vegetation som skyddar individerna för solen och andra dåliga väderförhållanden. De hittar sin föda vanligen mellan vattenytan och 100 meters djup men i sällsynta fall har de observerats 300 meter under vattenytan. Utanför parningstiden lever individerna främst ensamma. Hawaiis munksäl stannar vanligen i ett begränsat område som har en diameter på genomsnittlig 38 km och den gör ytters sällan utflykter till andra öar.[2]
Födan utgörs främst av fiskar och i viss mån även av bläckfiskar.[2]
Parningen sker mellan februari och mars, på grund av en fördröjd inplantering av ägget börjar den egentliga dräktigheten cirka 3 månader senare. Dräktigheten varar vanligen 11 månader och ungdjuret föds vanligen i april under nästa år. Honan äter ingenting under de 5 till 6 veckor digivning och tappar mycket av sin vikt. Ungdjuret är vid födelsen ungefär en meter lång och väger 14 till 18 kilogram. De ökar snabb i storlek och väger efter digivningsperioden 70 till 93 kilogram.[2] Ungarnas päls är vid födelsen ullig svart, den byts senare till päls som är silvergrå på ryggen samt sidan och vitaktig på buken. Denna päls ändras sedan stegvis till den brunaktiga pälsen som är vanlig för vuxna individer.
Liksom elefantsälar ömsar Hawaiis munksäl varje år det yttersta skiktet av huden tillsammans med gamla hår. För vuxna sälar sker bytet i sensommaren eller under hösten. Honor ömsar vanligen efter digivningen. Den nya pälsen skyddar individerna bättre mot vinterns kyla.
Könsmognaden infaller för båda kön efter 5 till 10 år. Livslängden uppskattas med 25 till 30 år.[2]
Vid atollöarna French Frigate Shoals undersöktes beteendet av flera vuxna individer med hjälp av satelliter och videokameror. Enligt dessa studier hittar de sin föda cirka 50 till 60 meter under vattenytan.[3][4][5]
Artens naturliga fiender utgörs främst av hajar.
Populationen minskade betydlig under de senaste åren på grund av ökad mänsklig aktivitet i sälens utbredningsområde. Ofta blir djuret stört vid sina gömställen. Under 1800-talet var arten ett vanligt jaktbyte som dödades med klubba av val- och säljägare. Från djuret utvanns kött, olja och skinn. Under andra världskriget blev Hawaiis munksäl jagad av den amerikanska armén under ockupationen av Laysan och Midwayöarna.[6]
På grund av människans utbredning blev allt fler munksälar förgiftade med ciguatera. De såras dessutom svårt när de hamnar i fiskenät och flera individer dör av skadorna. Hummer som är en av sälens huvudföda samt flera fiskarter blev överfiskade och ungdjur av Hawaiis munksäl har problem att fordra sin rätt mot konkurrenter som barracudafiskar och andra större rovfiskar. För att bevara beståndet inrättades olika skyddsområden som Papahanaumokuakea.
Alla hot tillsammans slår mycket hård mot arten. Den är nästan utrotad vid Hawaiis huvudöar. Populationen där uppskattas mindre än 150 individer. Främst förekommer arten vid Laysan, Midwayöarna, French Frigate Shoals, atollen Pearl and Hermes samt vid Lisianski.[7]
Wikimedia Commons har media som rör Hawaiis munksäl.
Hawaiis munksäl (Monachus schauinslandi) är en utrotningshotad sälart som förekommer endemiskt kring Hawaii.
Epitet, schauinslandi, i det vetenskapliga namnet syftar på den tyska zoologen Hugo Schauinsland som hittade den första skallen på ön Laysan.
Гавайською цей тюлень називається ʻIlio-holo-i-ka-uaua («собака, що порається в бурхливій воді»). Наукова назва виду походить від прізвища німецького вченого Hugo Hermann Schauinsland, який виявив череп тюленя на острові Лайсан у 1899 році[5] Назва «тюлень-монах» пов'язана зі складками шкіри на його голові, що нагадують капюшон ченця, а також із тим, що більшу частину часу вони проводять поодинці або в невеликих групах[3].
Довжина тіла — приблизно 225 см. Забарвлення дорослих самців на спині темно-коричневе або темно-сіро-коричневе, з білим або жовтувато-білим відтінком на череві. Самиці світліші і, як правило, більші за самців.
На початок ХХІ століття невеликі групи Monachus schauinslandi існують на північно-західних атолах Гавайських островів: Куре, Перл-енд-Хермес, Лисянського, Лайсан, Френч-Фрігейт-Шолс, Мідуей. В історичний час населяли також узбережжя островів головної групи Гавайського архіпелагу: Кауаї, Ніїхау, Оаху і Гаваї.
З 1958 по 1996 роки чисельність тюленів скоротилася на 60%. До 2004 року їх чисельність скоротилася до 1400 особин. У минулому зниження чисельності було в основному пов'язано з перепромислом. В даний час основними факторами, що впливають на скорочення популяції, є порушення спокою тюленів під час розмноження і загибель при попаданні в рибальські тенета.
Охороняються державою.
Еволюційна історія Monachus schauinslandi є вельми суперечливою, існує кілька гіпотез щодо філогенетичного зв'язку з іншими тюленями.[6] У зв'язку з відсутністю викопних решток зв'язки Monachus schauinslandi з іншими тюленями прослідкувати важко.
Ґрунтуючись на скелетній і судинній анатомії, Monachus schauinslandi вважається найпримітивнішим серед сьогоденних тюленів. Всі три види роду Monachus виникли у Північній Атлантиці. Monachus schauinslandi відокремився від його родичів близько 15 мільйонів років тому[6]
Згідно з даними розповсюдженими Національним управлінням океанічних і атмосферних досліджень Гавайські острови є домівкою Monachus schauinslandi вже мільйони років. Можливо Monachus schauinslandi мігрували на Гаваї 4-11 мільйони років тому через відкритий водний прохід між Північною і Південною Америкою — Центрально-Американським морським шляхом. Панамський перешийок закрив цей шлях близько 3 мільйонів років тому[7]
Екологія схожа з екологією Monachus monachus. Харчуються різними рифовими і придонними рибами, а також головоногими молюсками.
Самиці гавайського тюленя-монаха мають розтягнутий період дітонародження з грудня по серпень з піком у квітні — травні. Довжина немовляти близько 125 см, маса 16 кг. Чорний м'який волосяний покрив через 3-5 тижнів після народження замінюється сріблясто-сіро-блакитним на спині і сріблясто-білим на череві. Самиці приносять дитинчат у середньому раз на два роки. Линька тюленів відбувається з травня по листопад, в основному в липні.
Hải cẩu thầy tu Hawaii (Monachus schauinslandi) là một loài động vật có vú trong họ Hải cẩu thật sự, bộ Ăn thịt. Loài này được Matschie mô tả năm 1905.[2] Đây là loài đặc hữu quần đảo Hawaii.]].[3] Chúng là loài sống đơn độc. Hải cẩu thầy tu Hawaii là một trong hai loài hải cẩu thầy tu còn lại; loài kia là hải cẩu thầy tu Địa Trung Hải. Một loài thứ ba khác, hải cẩu Caribbe, đã tuyệt chủng.[4] Đây là loài hải cẩu duy nhất bản địa Hawaii.[5] Đây là loài nguy cấp phụ thuộc vào bảo tồn. Tổng cộng còn khoảng 1100 cá thể bị đe dọa bởi sự xâm lấn của con người, mức độ biến đổi gen rất thấp, bị dính lưới đánh cá, các mảnh vỡ biển, bệnh tật, và săn bắn thương mại lấy da. Người ta có thể áp dụng nhiều biện pháp bảo tồn sinh học như dịch chuyển vị trí, nuôi nhốt, làm sạch môi trường sống, và giáo dục công chúng về hải cẩu nhà sư Hawaii.[6][7][8]
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Bài viết về các loài trong bộ thú ăn thịt này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn. Hải cẩu thầy tu Hawaii (Monachus schauinslandi) là một loài động vật có vú trong họ Hải cẩu thật sự, bộ Ăn thịt. Loài này được Matschie mô tả năm 1905. Đây là loài đặc hữu quần đảo Hawaii.]]. Chúng là loài sống đơn độc. Hải cẩu thầy tu Hawaii là một trong hai loài hải cẩu thầy tu còn lại; loài kia là hải cẩu thầy tu Địa Trung Hải. Một loài thứ ba khác, hải cẩu Caribbe, đã tuyệt chủng. Đây là loài hải cẩu duy nhất bản địa Hawaii. Đây là loài nguy cấp phụ thuộc vào bảo tồn. Tổng cộng còn khoảng 1100 cá thể bị đe dọa bởi sự xâm lấn của con người, mức độ biến đổi gen rất thấp, bị dính lưới đánh cá, các mảnh vỡ biển, bệnh tật, và săn bắn thương mại lấy da. Người ta có thể áp dụng nhiều biện pháp bảo tồn sinh học như dịch chuyển vị trí, nuôi nhốt, làm sạch môi trường sống, và giáo dục công chúng về hải cẩu nhà sư Hawaii.
Monachus schauinslandi Matschie, 1905
Синонимы
Гавайский тюлень-монах[1] (лат. Monachus schauinslandi) — представитель рода тюлени-монахи (Monachus), семейства тюленевые (Phocidae). Находится под угрозой исчезновения.
Длина тела примерно 225 см. Окраска взрослых самцов на спине тёмно-коричневая или тёмно-серо-коричневая, с белым или желтовато-белым оттенком на брюхе. Самки более светлые и, как правило, крупнее самцов.
В настоящее время залежки размножающихся гавайских тюленей-монахов имеются на северо-западных атоллах Гавайских островов: Куре, Перл-энд-Хермес, Лисянского, Лейсан, Френч-Фригат-Шолс, Мидуэй. Прежде обитали также на островах главной группы Гавайского архипелага: Кауаи, Ниихау, Оаху и Гавайи.
С 1958 по 1996 годы численность тюленей сократилась на 60 %. К 2004 году их численность сократилась до 1400 особей. В прошлом снижение численности было в основном связано с перепромыслом. В настоящее время основными факторами, влияющими на сокращение популяции, являются нарушение покоя тюленей во время размножения и гибель при попадании в рыболовные сети.
В США охраняются законом.
Экология сходна с таковой тюленя-монаха. Питаются различными рифовыми и придонными рыбами, а также головоногими моллюсками.
Самки гавайского тюленя-монаха имеют растянутый период деторождения с декабря по август с пиком в апреле — мае. Длина новорождённого около 125 см, масса 16 кг. Чёрный мягкий волосяной покров спустя 3—5 недель после рождения заменяется серебристо-серо-голубым на спине и серебристо-белым на брюхе. Самки приносят детёнышей, по-видимому, раз в два года. Линька тюленей происходит с мая по ноябрь, в основном в июле.
Гавайский тюлень-монах (лат. Monachus schauinslandi) — представитель рода тюлени-монахи (Monachus), семейства тюленевые (Phocidae). Находится под угрозой исчезновения.
夏威夷僧海豹（學名：Neomonachus schauinslandi）是僧海豹屬下的一種瀕危物種，原產於夏威夷群島，因而得名。[2] 此外它也是夏威夷灰白蝙蝠之外當地唯一的原生哺乳動物。[3] 因為人類的過度捕殺和棲息地破壞，夏威夷僧海豹的數量現僅有1,100左右。[4][5][6]
夏威夷僧海豹在當地語言中稱為ʻIlio-holo-i-ka-uaua，意思是“在波浪中奔跑的狗”。其學名中的種加詞則是來自1899年于在萊桑島發現了夏威夷僧海豹頭骨的德國科學家雨果·赫爾曼·绍因斯兰（Hugo Hermann Schauinsland）。[7]
夏威夷僧海豹有著灰色的毛皮、白色的腹部，身體修長；頭部扁平而較小。[8][9] 其體格使得其可以在深海珊瑚礁里尋覓魚蝦及章魚、烏賊等食物。[10] 在不捕獵時，它們會躺在西北夏威夷群島的沙灘上嗮太陽。[11] 成年夏威夷海豹重170～205公斤（375～452英磅），體長2.1～2.3米（6英尺11英寸～7英尺7英寸）。[8]
夏威夷僧海豹（學名：Neomonachus schauinslandi）是僧海豹屬下的一種瀕危物種，原產於夏威夷群島，因而得名。 此外它也是夏威夷灰白蝙蝠之外當地唯一的原生哺乳動物。 因為人類的過度捕殺和棲息地破壞，夏威夷僧海豹的數量現僅有1,100左右。
ワシントン条約附属書I 分類 界 : 動物界 Animalia 門 : 脊索動物門 Chordata 亜門 : 脊椎動物亜門 Vertebrata 綱 : 哺乳綱 Mammalia 目 : ネコ目 Carnivora 科 : アザラシ科 Phocidae 亜科 : モンクアザラシ亜科 Monachinae 属 : モンクアザラシ属 Monachus 種 : ハワイモンクアザラシハワイモンクアザラシ（Monachus schauinslandi）は、ネコ目（食肉目）アザラシ科モンクアザラシ属に分類される鰭脚類。別名タイヘイヨウモンクアザラシ。 ハワイ語ではʻIlio-holo-i-ka-uauaという。
アメリカ合衆国（北西ハワイ諸島）[1][2]固有種。ハワイ島で見られることもあり、ウェーク島、ジョンストン島、パルミラ環礁での発見例もある[2]。
体長オス210センチメートル、メス230センチメートル[1][2]。体重オス150-200キログラム、メス250-270キログラム[1][2]。
出産直後の幼獣は全身の毛衣が黒い[2]。オスの成獣（およびメスの成獣の一部）は全身の毛衣が褐色で、不規則に斑紋が入る個体もいる[2]。幼獣やメスの成獣は換毛直後は背面の毛衣が灰色、腹面の毛衣が淡灰色で、時間経過に伴い背面が褐色、腹面が黄色みを帯びる[2]。
食性は動物食で、少なくとも沿岸域では魚類、甲殻類、軟体動物を食べる[2]。
繁殖形態は胎生。12-翌8月（主に3-5月）に茂みで1回に1頭の幼獣を隔年（年に1回産むこともある）で産む[2]。授乳期間は5-6週間[2]。メスは生後5年で初産を迎える[1]。寿命は30年[1]。
乱獲、人間による撹乱（繁殖地への侵入による育児放棄）などにより生息数は激減した[1][2]。また生息数は減少していることに加えてサメによる襲撃、漁業による混獲、サンゴ礁破壊によるシガテラ中毒も生息数増加の妨げになっていると推定されている[1][2]。
この項目は、動物に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています（Portal:生き物と自然／プロジェクト:生物）。 ハワイモンクアザラシ（Monachus schauinslandi）は、ネコ目（食肉目）アザラシ科モンクアザラシ属に分類される鰭脚類。別名タイヘイヨウモンクアザラシ。 ハワイ語ではʻIlio-holo-i-ka-uauaという。
하와이몽크물범(Hawaiian monk seal, Neomonachus schauinslandi)는 하와이 제도에 서식하는 멸종위기에 놓여 있는 몽크물범의 일종이다. 보호정책에도 불구하고 수가 줄고 있지만, 다른 몽크물범에 비해서는 양호하다.
다음은 물범과의 계통 분류이다.[3]
물범과 남방물범아과 몽크물범족 몽크물범속 네오모나쿠스속† 카리브해몽크물범
코끼리물범족 게잡이물범족 북방물범아과 물범속 고리무늬물범속하와이몽크물범(Hawaiian monk seal, Neomonachus schauinslandi)는 하와이 제도에 서식하는 멸종위기에 놓여 있는 몽크물범의 일종이다. 보호정책에도 불구하고 수가 줄고 있지만, 다른 몽크물범에 비해서는 양호하다.
