Southern Right Whale Dolphin

El dofí meridional (Lissodelphis peronii) és un dofí del gènere Lissodelphis. Els dofins meridionals són els únics dofins de l'hemisferi sud que manquen d'aleta dorsal. Són més petits que els dofins septentrionals i tenen més color blanc al cap i els flancs. Tenen un cos esvelt i gràcil que és de color negre a la part de dalt i blanc a la part d'avall. Les aletes són principalment blanques i són petites corbades. Tenen entre 43 i 49 dents a cada filera de cada maxil·lar.

Sydlig rethvalsdelfin (Lissodelphis peronii) er den ene af to arter i slægten rethvalsdelfiner. Den forekommer kun på den sydlige halvkugle i koldt tempererede og subantarktiske havområder. Den er tilsyneladende ret almindelig, men kun lidt vides om arten.^[1] Kroppens overside er sort og undersiden er hvid med skarp grænse mellem de to farver, hvilket sammen med den manglende rygfinne gør den nem at kende. Sydlig rethvalsdelfin er den eneste delfin på den sydlige halvkugle uden rygfinne.^[2]

Kilder

Verbreitungskarte des Südlichen Glattdelfins

Der Südliche Glattdelfin (Lissodelphis peronii) ist einer der beiden Vertreter der Gattung Lissodelphis innerhalb der Delfine (Delphinidae). Er ist in der offenen See der gesamten gemäßigten Zone der Südhalbkugel zuhause. Das nördlichste Vorkommen liegt am 19. südlichen Breitengrad.

Merkmale

Der Glattdelfin unterscheidet sich von allen anderen Delfinarten durch das völlige Fehlen der Finne. Südliche Glattdelfine sind sehr schlanke, bis etwa 3 m lange Delfine. Weibchen erreichen ca. eine Länge von 2,3 m. Das Höchstgewicht liegt bei etwa 100 kg. Schnauze, Flossen, Flanken und der Bauch sind weiß, ansonsten ist dieser Delfin schwarz. Kälber sind grau oder gefleckt.

Verhalten

Der Südliche Glattdelfin tritt in Schulen mit bis zu 1000 Tieren auf.

Bestand

Es gibt keine Schätzungen für den Gesamtbestand.

Literatur

• R. Wandrey: Wale und Robben der Welt. Franckh-Kosmos Verlags GmbH, 1997, ISBN 3-440-07047-6

Weblinks

– Sammlung von Bildern, Videos und Audiodateien

• Lissodelphis peronii in der Roten Liste gefährdeter Arten der IUCN 2013.1. Eingestellt von: Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K.A., Karkzmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y., Wells, R.S. & Wilson, B., 2012. Abgerufen am 20. September 2013.

The southern right whale dolphin (Lissodelphis peronii) is a small and slender species of cetacean, found in cool waters of the Southern Hemisphere. It is one of two species of right whale dolphin (genus Lissodelphis). This genus is characterized by the lack of a dorsal fin. The other species, the northern right whale dolphin (Lissodelphis borealis), is found in deep oceans of the Northern Hemisphere and has a different pigmentation pattern than the southern right whale dolphin.

Taxonomy

The species was first published by Bernard Germain de Lacépède in 1804. The southern right whale dolphins together with the northern right whale dolphins are the only members of the genus Lissodelphis, which name is derived from the Greek, with lisso meaning smooth, and delphis meaning dolphin. Recent classifications have placed Lissodelphis within the Delphinidae, the oceanic dolphin family of cetaceans.^[3] The specific epithet peronii commemorates François Péron, a French naturalist who saw the species near Tasmania during an expedition in 1802.^[4] Although some doubts remain on the validity of these two species, most authors currently retain them as separate species.^[5][6]

Both species in the genus are referred to by the name "right whale dolphin", a name derived from the right whales (Eubalaena) which also lack a dorsal fin.^[7] Other common names for the southern right whale dolphin include: whitebellied right whale dolphin, southern right whale porpoise, mealy-mouthed porpoise, tunina (tonina) sin aleta (Spanish), delfin (delphin) liso austral (Spanish), minami semi-iruka (Japanese), dauphin de Peron (French), yuzhnyi kitovidnyi delfin (Russian), Südlicher Glattdelfin (German), and zuidelijke gladde dolfijn (Dutch).

Description

Southern right whale dolphins can be easily distinguished from other cetacean species within their range as they are the only dolphins without dorsal fins in the Southern Hemisphere. They have streamlined and graceful bodies, a single blowhole and a short and defined beak, possessing between 39 and 50 teeth per row.^[5][6]

A sharp dividing line separates the black dorsal part from the white ventral part of the body, running from the tail stock forward, dipping down to the flipper insertion and sweeping back up, below the eyes, to cross the melon between the blowhole and snout crease.^[5][8][6] Younger individuals can be grey/brownish dorsally but develop adult coloration within the first year.^[9][5][6] The flippers of the southern right whale dolphins are small, recurved, predominantly white and located about one-quarter of the way back from the snout tip. Their flukes are small, have a white underside and dark grey upper side, with a notch in the middle and concave trailing edges.^[5]

Variability in the size of these black and white areas exists.^[10][11] More extensive anomalous pigmentation has been observed, with records of pure all-white individuals,^[12][13] as well as melanistic (all-black) individuals.^[14][15] In 1998, a potential hybrid of a southern right whale dolphin and a dusky dolphin (Lagenorhynchus obscurus) was observed and subsequently described in 2002. This animal showed intermediate morphological features between the two species.^[8]

Newborn calves measure around 86 cm (34 in) in length and weigh around 5 kg (11 lb), while adults range between 2.18 and 2.5 m (7 ft 2 in and 8 ft 2 in) and weight between 60–100 kg (130–220 lb) on average.^[5][14][6] The maximum weight for southern right whale dolphins is 116 kg, with maximum lengths reaching 297 cm (117 in) in males and 230 cm (91 in) in females but few specimens have been examined and it is expected they grow larger.^[10] On average, males tend to grow slightly larger than females. Little is known of this species’ reproductive biology. Research suggests that males reach sexual maturity at lengths between 212–220 cm (83–87 in) and females between 206–212 cm (81–83 in).^[5]

Population status

There are no current global abundance and mortality estimates of the species although it is considered a fairly common and abundant species along its range,^[5] particularly in Chile.^[16] The very low sighting rate is most likely caused by a lack of sampling effort and due to the difficulties of sighting the animals in their offshore habitat.

Distribution

Southern right whale dolphins have a circumpolar distribution across the Southern Hemisphere, generally occurring in cool temperate to Sub-Antarctic waters between 30°S and 65°S.^[16][5][14] The precise boundary of their range has not been estimated or closely studied but the southern limit of the species appears to be bounded by the Antarctic Convergence while the northern limit seems bounded by the Tropical Convergence although rare sightings beyond these limits have been recorded.^[16] Most sightings of the southern right whale dolphins occur in offshore and deep waters, with temperatures ranging between 1 and 20 °C. In regions where deep waters approach the coast and in upwelling areas, they have occasionally been observed near shore.^[17][5][11]

South America

The species is known to be abundant along the western coasts of South America, ranging from Cape Horn (55°58’S) to Arica (18°28’S), with the northernmost record at 12°30’S near Pucusana (Peru). Although the southern right whale dolphin is considered abundant, only few confirmed records of the species in the Eastern South Pacific exist.^[16][18]

Preliminary boat surveys and stranding and fishery records suggest that southern right whale dolphins may be one of the most common species of cetacean in northern Chile. The range extends until 170 km (110 mi) offshore north of 40°S and 250 km (160 mi) off the southern coast of Chile and it has been suggested that at least a part of this Chilean population migrates northbound in the austral winter and spring, when the coastal component of the cold Humboldt Current and cool coastal upwelling are strongest.^[16][5] An extension of the range to the North, associated to cold-water currents and food availability, has also been observed in Brazil, where a stranded individual was found in 1995 in an area where the warm Brazil Current meets the cold Malvinas Current.^[19]

In 2018, two groups were sighted in the western area of the Strait of Magellan in Chile. It was unclear through which route and why they entered the Magellan Strait but these were the first sightings of live southern right whales dolphins in this shallow area.^[20] A few reports of solitary stranded specimens in exterior channels south of 40°S and the Beagle Channel have also shown their occurrence inside shallow channel systems.^[21][22] It has been hypothesized they may enter these channels accidentally or because of poor health.^[16] In the past, a high number of stranded southern right whale dolphins were reported on beaches of north-central chile, most of which were discarded animals by-caught In fishing nets. An increase in strandings is possibly due to the developing swordfish gillnet fishery off northern Chile.^[16]

The waters of the Patagonian continental shelf of Argentina harbor a high diversity of cetaceans, including southern right whale dolphins. They are known to occur in cold waters off Santa Cruz Province, the Falkland Islands,^[23] as well as off Tierra del Fuego.^[21] Sightings in coastal areas are rare but exist in Mar del Plata^[24] and in Golfo Nuevo, where three southern right whale dolphins were observed once during the summer of 1992.^[8]

Africa

In Southern Africa, the range is associated with cold currents up the western and southern coasts, ranging northwards as far as about 23°S due to the cold counter clockwise Benguela Current. The species has been found to occur year-round in a localized area on the southwestern coast of Namibia, in Lüderitz, linked to the strong Lüderitz upwelling cell area and high productivity waters.^[11][14] These animals may occasionally extend their range into South African waters although more sampling effort is needed to support this. Just one confirmed sighting of the species exists from the South African coast, just south of the Orange River. Southern right whale dolphins have also been observed in waters around Marion Island.^[9][11][25]

Australia

The species has been observed in Australian waters since 1802, although only few actual records exist since then.^[26] They are found off southern continental Australia including sightings south and southwestward of Tasmania, in the Great Australian Bight and off south-western Australia.^[27] One pair was sighted on the 20th of October 1910 at 42°51S, 153°56E, approximately 460 km to the east of Australia, in the Tasman Sea.^[28] No localised areas where the species occurs year-round are known from the coast of Australia, although more survey effort could result in the identification of these areas, similar to the one off the west coast of Namibia.^[11][7]

Few stranded individuals have been documented in Australian waters.^[10] In December 2019, a dolphin washed up on a beach at Port Fairy, Victoria, with the deceased animal being assessed by state authorities, researchers and local Australian aboriginal elders. Another dolphin washed up in January 2020 and was photographed, but the dead animal washed back off the beach. The dual strandings were described as ‘very unusual’ by authorities.^[29]

New Zealand

One of the earliest records of this species in New Zealand waters was during the Terra Nova Expedition, when a pair was sighted approximately 145 km west-south-west of Nugget Point Lighthouse, South Island at 47°04'S, 171°33'E.^[28] Southern right whale dolphins have been observed at sea to the southeast of New Zealand ^[30][31] and are largely found between the Subtropical Convergence and the subantarctic waters to the south of it, between surface temperatures of 9°-17 °C.^[31]

The first recorded photographs of the species globally, were from a stranding of three individuals in New Zealand in 1952, which were apparently rescued.^[32] Since then there have been a number of strandings around the country, including seven events between 1970 and 1981^[10] and a mass stranding of 75 individuals occurred at the Chatham In 1988.^[33] More recently a stranding of a single animal occurred at Mahia Beach, North Island in April 2020 which was euthanised by the Department of Conservation.^[34] The northernmost record of a stranding in New Zealand was of a ~200 cm long male at Whananaki (35° 31’S, 174° 28’), Northland, in November 1979.^[10]

Southern right whale dolphins are occasionally observed off the coast of Kaikoura, on the eastern coast of South Island, typically in groups of 50-200, although larger groups of>500 are also encountered.^[15] In 1967, research showed that the species could also be found off-shore from the Chatham, Bounty and Antipodes Islands (approximately 43-57°S, 168-158°E) between January and March.^[31]

Behavior

Social

Southern right whale dolphins porpoising. One melanistic individual can be observed in this group (on the foreground in the middle)

Southern right whale dolphins are generally gregarious and have been documented in aggregations of more than 1000 individuals^[35] although small groups of one to 10 have also been reported.^[28][31][35] Mean group size estimates differ and range between 52 and 368 off northern Chile,^[16][7][36] however, they typically live in groups of 100-200 individuals.^[37] Pods of just a few animals have also been observed, often associated with other cetacean species. Mixed groups with Dusky dolphins (Lagenorhynchus obscurus) appear common in the southern Atlantic and have occasionally been reported in New-Zealand,^[38][28] off Southwest Africa^[11][9] and along the coast of southern Chile.^[39] They have been observed to intermix freely with pilot whales (Globicephala spp.)^[40] and in Chile, associations with common dolphins (Delphinus delphis) have been reported.^[5][16] Along their range they have also occasionally been sighted with hourglass dolphins (Lagenorhynchus cruciger), common bottlenose dolphins (Tursiops truncatus)^[40] and fin whales (Balaenoptera physalus).^[11][5]

Four basic herd configuration types have been reported and conform to the types described for the northern right whale dolphin: (1) Densely packed schools, without identifiable subgroups; (2) herds of scattered subgroups of various sizes; (3) V-shaped herds; and (4) herds in ‘’chorus line’’ formation.^[9][41] Their movement is very graceful and they often move by leaping out of the water continuously. When they swim slowly, they expose only a small area of the head and back while surfacing to breath. When travelling at higher speeds they have been observed to either (1) swim just below the surface, surfacing briefly to breath and then submerge or (2) swim rapidly at the surface, performing low-angle leaps covering much surface distance. Breaching, belly-flopping, side-slapping, and lob-tailing (slapping the flukes on the water surface) have been witnessed.^[14] Some groups will avoid boats, whereas others approach and possibly bow-ride. Few direct speed measurements at sea exist but swimming speed has been reported to be 22 km/h (14 mph).^[9][11]

Foraging

Southern right whale dolphins prey on an undetermined range of fish, but it has been suggested they prey primarily on mesopelagic fish and squid, and may dive to depths in excess of 200 m (660 ft) in search of food.^[10][5] However, little is known of their particular habits, and it is unknown whether they generally search for their food at these greater depths or near the surface.^[7] Based on stomach contents, epipelagic coastal food habits, mesopelagic or a combination of both were suggested for southern right whale dolphins.^[42][10][43] Geographical variability in prey species has been observed by comparing stomach contents of animals from central Chile and New Zealand.^[42][16][20]

The species itself is presumably occasionally predated upon by larger sharks and killer whales (Orcinus orca) however, other predators might exist. In 1983, an intact dolphin measuring 0.86 m (2 ft 10 in) was found in the stomach of a 1.7 m (5 ft 7 in) Patagonian toothfish (Dissostichus eleginoides) taken off central Chile, and in 1990, a foetus was discovered inside a sleeper shark (Somniosus cf. pacificus).^[16][5]

Threats

Overall, clear evidence of the impact of potential threats on the species are sparse. Southern right whale dolphins were taken by whaling operations of the 19th century, primarily for their meat.^[9] In the past they have been infrequently caught off the coasts of Peru and Chile, where their meat and blubber were used as food and crab bait.^[42][5][14] High levels of bycaught animals have been recorded in the swordfish (Xiphias gladius) driftnet fishery in northern Chile, which started in the early 1980s,^[44] and to a lesser extent, the species has also been incidentally caught in driftnets along the coast of Peru.^[45]

Large numbers of southern right whale dolphins are sometimes taken by gillnetting and longline fishing in oceans off the southern coast of Australia.^[7] Off the west coast of southern Africa, no evidence exists of bycatch in gillnet fisheries, but there may be competition for forage resources with pelagic trawl fisheries due to the pelagic distribution of the species and their squid based diet.^[25] The direct and indirect impacts of global climate change on the southern right whale dolphin are largely unknown, but could have a cascading effect on the movement and feeding ecology. Seismic activity, for oil and gas, might also be a minor threat.^[46][47][25] No reported attempts to capture live southern right whale dolphins exist.

Conservation status

As of 2018, the Global IUCN Red List classifies the southern right whale dolphin as Least Concern (LC), due to their apparent wide distribution in pelagic waters of the sub-Antarctic and the lack of evidence of severe threats to the populations. However, the species remains extremely data-poor throughout its range so the assessment should be considered provisional until more knowledge is obtained.^[48]

The 2016 Regional Red List of Mammals of South Africa, Lesotho and Swaziland also classified the species as Least Concern^[25] while in Australia and Chile, based on the limited current knowledge on the species, southern right whale dolphins are classified as Data Deficient by the Action Plan for Australian Mammals^[49][30] and the Chilean Species National List respectively.^[50] Under the New Zealand Threat Classification System this species is listed locally as Data Deficient.^[51]

Southern right whale dolphins are listed in Appendix II of the Convention on International Trade in Endangered Species (CITES) and the species is subject to International Whaling Commission (IWC) regulations. In South-Africa, the species is protected by the Marine Living Resources Act (No. 18 of 1998).^[25] They are included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU)^[52] and the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MoU).^[53] Within the Australian Whale Sanctuary, all cetaceans, including the southern right whale dolphins are protected under the Environment Protection and Biodiversity Conservation Act (EPBC Act). The Sanctuary includes all Commonwealth waters from the three nautical mile state waters limit out to the boundary of the Australian Exclusive Economic Zone (out to 200 nautical miles and further in some places). The species is also protected within the Indian Ocean Sanctuary and Southern Ocean Sanctuary.^[7] Although the species is included in legislation, no specific conservation measures have been identified for this species as throughout its range, there is still a clear deficiency of data to build these measures upon.

See also

• Right whale dolphin
• Northern right whale dolphin
• List of cetaceans
• Marine biology

References

La Perona delfeno, Perona lisodelfo aŭ lisodelfo perona (Lissodelphis peronii) estas malgranda svelta specio de mamulo kiu vivas en malvarmaj akvoj de la Suda Hemisfero. Tiu delfeno estas unu el la du specioj de lisodelfo; Lissodelphis borealis, la alia, nome norda lisodelfo aŭ Nigradorsa delfeno, troviĝas en profundaj oceanaj akvoj de la Norda Hemisfero.

Priskribo

Franca desegno el 1847.

La Peronaj delfenoj estas la nuraj delfenoj sen dorsaj naĝiloj en la Suda Hemisfero. Ili estas pli malgrandaj ol la nordhemisferaj lisodelfoj kaj havas pli da blanko en siaj kapoj kaj flankoj. Ili havas fajnajn, graciajn korpojn kiuj estas nigraj supre kaj blankaj sube. Iliaj naĝiloj estas ĉefe blankaj kaj estas malgrandaj kaj kurbaj. Iliaj vostoj estas malgrandaj kun kojno meze kaj konkavaj vosto-eĝoj. Iliaj bekoj estas malgrandaj sed distingaj. Ili havas inter 43 kaj 49 dentoj en ĉiu linio de ambaŭ makzeloj.

La distribua arearo de la specio estas subtropikaj al ĉeantarktaj oceanoj de la Suda Hemisfero. Tiu teritorio kaj la totala populacio ne estis ĉirkaŭkalkulita aŭ precize studita. Estis registritaj grandaj populacioj ĉe la okcidentaj marbordoj de Sudameriko, kie ili estas celo de balenkaptado; ĝi estis priskribita kiel abunda en tiu regiono kaj ĉe la marbordo de Novzelando. Ties arearo estas asocia kun malvarmaj marfluoj ĝis la okcidentaj kaj sudaj marbordoj de Afriko, kun koncentroj registritaj ĉe Namibio.^[1]

La specio estis registrita kun aliaj cetacoj kiel Lagenorhynchus obscurus kaj la globkapulo Globicephala macrorhynchus.^[2]

La Perona delfeno veturas laŭ grupoj de ĝis 1000 individuoj, kaj 52 estas la averaĝa grupokvanto. Oni registris amasajn surstrandiĝojn de L. peronii, ĝis grupoj de 77.^[1]

La specio estis por la unua foje publikigita de Bernard Germain de Lacépède en 1804. La genro Lissodelphis, estas metita en la familio de Delfenedoj, nome oceania delfena familio de cetacoj.^[3] La nomo de la genro estas derivita el la greka lisso, milda, kaj delfis. La specia epiteto peronii rememorigas François Péron, kiu vidis la specion proksime de Tasmanio dum ekspedicio en 1800.^[4] Komunaj nomoj de la specio estas suda balendelfeno kaj serpenta porkoceto.^[5] Ambaŭ specioj de la genro estas referencataj ankaŭ per la nomo "veraj balendelfenoj", nomo derivita el la veraj balenoj (Eubalaena) kiuj same ne havas dorsan naĝilon.^[1]

Notoj

1. ↑ ^{1,0 1,1 1,2} Lissodelphis peronii. Species Profile and Threats Database. Department of the Environment, Water, Heritage and the Arts, Canberra.. Alirita 2009-07-16.
2. ↑ Lissodelphis borealis Right Whale Dolphin. MarineBio. Alirita 2009-07-15.
3. ↑ "Lissodelphis peronii (Lacépède, 1804)". Integrata Taksonomia Informa Sistemo. Alirita la 15an de Novembro 2018.
4. ↑ . Southern Right Whale Dolphin. Whales & Whale Spotting. Alirita 2009-07-16.
5. ↑ Lissodelphis peronii (Peale, 1848). Encyclopedia of life. eol.org. Alirita 2009-07-15.

Bibliografio

• National Audubon Society: Guide to Marine Mammals of the World ISBN 0-375-41141-0
• Encyclopedia of Marine Mammals ISBN 0-12-551340-2
• Whales, Dolphins and Porpoises, Mark Carwardine 1995 ISBN 0-7513-2781-6

El delfín meridional sin aleta o delfín liso del sur (Lissodelphis peronii) es una especie de cetáceo odontoceto de la familia Delphinidae. Es el único delfín sin aleta dorsal en el hemisferio sur.

Descripción

Es un delfín alargado y esbelto. La característica más importante es la ausencia de la aleta dorsal. Mide entre 2 y 3 m. La zona dorsal es negra, y la ventral, incluida la cara y el melón, son de color blanco. Su dieta se basa en peces, calamares y pulpos.

Tiene un cuerpo pequeño, estilizado y delgado. Sus aletas son principalmente blancas, pequeñas y curvadas, con una muesca en el borde medio y cóncava al final. Su hocico es corto, bien definido y blanco. Tienen entre 43 a 49 dientes en cada hilera de ambas mandíbulas. El peso está entre 60 y 100 kilos. Debido a su forma altamente hidrodinámica conforman unos de los cetáceos más veloces del mundo llegando a alcanzar velocidades de hasta 60 km/h.

Población y distribución

Habita en el hemisferio sur, en aguas frías, acercándose ocasionalmente a la costa. Esta especie nada en grupos de dos hasta 100 individuos. Se asocian con otros cetáceos pequeños. Se desplazan dando grandes saltos, frecuentemente en parejas, a ras de la superficie del agua.

Apareamiento y caza

Como otros cetáceos, los delfines utilizan los sonidos, la danza y el salto para comunicarse, orientarse y alcanzar sus presas; además utilizan la ecolocación.

Referencias

• https://web.archive.org/web/20081009175236/http://www.leviathanchile.org/mamiferos_cet_fam6_sp12.htm

Lissodelphis peronii Lissodelphis generoko animalia da. Artiodaktiloen barruko Delphinidae familian sailkatuta dago. Animalia txikia eta liraina da, Hego hemisferioko ur hotzatan bizi dena. Genero berbereko beste espeziea, Lissodelphis borealis, Ipar hemisferioan bizi da.

Deskribapena

Lissodelphis peronii da Hego hemisferioko izurdeen artean hegats dortsalik ez duen bakarra. Iparraldeko espeziea baino txikiagoak dira, eta zuriagoak dira euren albo eta buruan.

Erreferentziak

• 'Lissodelphis peronii'ri buruzko informazioa Mammals of The World datubasean

Ikus, gainera

• Delphinidae

Lissodelphis peronii

Le Dauphin aptère austral (Lissodelphis peronii) est une espèce de cétacé odontocète de la famille des Delphinidae. C'est l'unique dauphin sans aileron dorsal de l'Hémisphère Sud.

Description

Comparaison de la taille d'un dauphin aptère austral avec celle d'un plongeur

Les adultes de cette espèce mesurent de 2 à 3 m de long, rarement plus, les mâles étant en moyenne plus grands que les femelles, pour un poids de 60 à 100 kg^[1].

Comme tous les dauphins du genre Lissodelphis, ils ne possèdent pas de nageoire dorsale.

Ils sont globalement noir sur la face dorsale et blanc sur la face ventrale, la limite du noir partant globalement de la base du bec, passant sous les yeux et au-dessus de la base des nageoires, puis remontant en position plus dorsale jusqu'aux nageoires caudales. Des variations de couleur existent au niveau individuel (taches grises ou noir sur le blanc, taches grises ou blanches sur le noir).

Les petits naissent davantage marron et gris que blanc et noir et acquièrent leurs couleurs adultes vers l'âge d’un an^[1].

Répartition et habitat

Aire de répartition du Dauphin aptère austral

Le Dauphin aptère austral est pélagique. Il vit dans les mers et océans froids ou tempérés froids de l'Hémisphère Sud (généralement entre 8 et 19 °C^[1]), dont les eaux riches en nutriments sont poissonneuses.

Son aire de répartition, grossièrement circumpolaire, coïncide globalement avec le front polaire sub-antarctique, avec toutefois une remontée vers le Nord le long des côtes Pacifique du Chili et du Pérou.

Biologie et comportement

Déplacement en banc d’une troupe de Lissodelphis peronii

Notes et références

Il lissodelfino australe (Lissodelphis peronii) è un cetaceo odontoceto appartenente alla famiglia Delphinidae.

Descrizione fisica

Di dimensioni più ridotte del lissodelfino boreale (60–100 kg), è l'unico delfino dell'emisfero sud ad essere privo di pinna dorsale; può essere facilmente riconosciuto ad occhio nudo a distanza ravvicinata, mentre in lontananza ricorda un pinguino.

Comportamento

Lissodelfino australe "porpoising"

Raramente effettua il lobtailing e il breaching e quando lo effettua non si osservano capriole o peripezie simili. Quando sono spaventati o quando nuotano veloci si osserva il porpoising. Può rimanere in apnea per 6 minuti.

Distribuzione

Si riscontra poco frequentemente nelle acque temperate, dal Cile settentrionale al largo del Perù (ma è avvistato regolarmente anche nelle coste della Nuova Zelanda), mentre è più caratteristico nella corrente delle Falkland, tra la Patagonia e le Isole Falkland.

Bibliografia

• (EN) Braulik, G. 2018, Lissodelphis peronii, su IUCN Red List of Threatened Species, Versione 2020.2, IUCN, 2020.

De zuidelijke gladde dolfijn (Lissodelphis peronii) is een dolfijn uit het geslacht der gladde dolfijnen (Lissodelphis). De zuidelijke gladde dolfijn komt voor op het Zuidelijk Halfrond. Het enige andere lid van het geslacht, de noordelijke gladde dolfijn (Lissodelphis borealis), leeft in de Noordelijke Stille Oceaan. De zuidelijke gladde dolfijn dankt zijn soortaanduiding peronii aan de Franse bioloog François Peron, die het dier voor het eerst in 1800 waarnam voor de kust van Tasmanië.

Beschrijving

Een afbeelding uit 1847

De zuidelijke gladde dolfijn is een kleine, slanke dolfijn, de enige dolfijnensoort op het Zuidelijk Halfrond zonder rugvin. De soort heeft een korte snuit, kleine, gebogen en spits aflopende borstvinnen en een kleine, licht ingekerfde staart, die spits is aan de uiteinden. Er zijn 44 tot 49 spitse tanden in iedere kaakhelft. De zuidelijke gladde dolfijn is zwart-wit van kleur. De beide kleuren zijn duidelijk van elkaar gescheiden. Het zwarte vlak loopt over de rug, de bovenzijde van de staart, het voorste deel van de flanken en de kop tot voorbij de ogen. Het witte vlak bedekt de gehele onderzijde, van de onderzijde van de staart tot de keel en bek, evenals het voorhoofd, het grootste deel van de flanken en de borstvinnen. De voor- en achterrand van de borstvinnen hebben een donkere rand. Jonge dieren zijn geheel grijs van kleur. De mannetjes van de zuidelijke gladde dolfijn worden tussen de 180 en 300 cm lang en ongeveer zestig tot honderd kilogram zwaar. Vrouwtjes blijven iets kleiner dan mannetjes, meestal zo'n 180 tot 230 cm. Een jong is bij de geboorte ongeveer 70 cm lang. Jonge dieren zijn eerst grijs van kleur voordat ze het zwart-witte kleurenpatroon krijgen.

Verspreiding

De zuidelijke gladde dolfijn leeft in de gematigd koude tot subantarctische wateren ten zuiden van de Steenbokskeerkring. De meest noordelijke waarneming vond plaats op 19° zuiderbreedte. De soort komt voornamelijk in diepere wateren voor, maar soms ook dichter bij de kust.

Leefwijze

Hij leeft in grote groepen van twintig tot honderd dieren, maar er zijn ook groepen met meer dan duizend dieren waargenomen. Ook schoolt hij regelmatig samen met andere walvissoorten. Massale strandingen komen soms voor. De zuidelijke gladde dolfijn jaagt op pijlinktvissen en vissen als lantaarnvissen en harders.

Aan het wateroppervlak maakt de soort lange lage sprongen, slaat met de staart op het water en glijdt met de buik omhoog over het water. Ook zoekt hij schepen op en surft op de boeggolf van een schip. Deze dolfijnensoort wordt voornamelijk waargenomen op walvisexcursies tussen de Falklandeilanden en Antarctica en in de zeeën rond Argentinië, Chili, Nieuw-Zeeland en Zuid-Afrika.

Delfiniec płaszczowy^[4], delfin płaszczowy^[5] (Lissodelphis peronii) – gatunek ssaka z rodziny delfinowatych (Delphinidae).

Występowanie

Żyje na pełnym morzu, z dala od brzegów w strefie mórz półkuli południowej w stadach do kilkudziesięciu sztuk.

Opis

Ciało szczupłe, opływowe, kolor ciała z wierzchu czarny, od spodu biały, dziób krótki. Charakterystyczny dla tego gatunku jest brak płetwy grzbietowej.

Długość ciała 1,8-2,8 m.
Waga 60-100 kg.
Młode nowo narodzone osobniki mierzą 80-100 cm długości. Potomstwem opiekuje się samica.

Pokarm

Głównym składnikiem diety są kałamarnice, ryby, ośmiornice.

Przypisy

O Lissodelphis peronii é popularmente chamado de Golfinho-liso-do-sul, sendo caracterizado pela ausência da nadadeira dorsal. Esse cetáceo faz parte da família Delphinidae, cujos representantes são os mais conhecidos dentre os odontocetos. Sua ocorrência registrada se restringe ao hemisfério sul, com a maior concentração de dados nas águas temperadas e subantárticas.

Etimologia

O termo Lissodelphis vem do latim lisso (liso) e delphis (golfinho). Já peronii é o epíteto específico em homenagem a François Péron, naturalista que registrou a espécie pela primeira vez em 1802. Entretanto, a espécie só foi descrita de fato em 1804, por Lacépède.

Descrição Morfológica

Os golfinhos-lisos-do-sul são facilmente identificados por serem os únicos golfinhos sem a nadadeira dorsal no hemisfério sul. Possuem corpos muito hidrodinâmicos, apresentando apenas um espiráculo (fenda respiratória) e um focinho curto, mas bem definido, com 39 a 50 dentes por fileira. A parte ventral do corpo é branca, enquanto a parte dorsal é preta. Os golfinhos juvenis dessa espécie apresentam uma cor cinza ou marrom dorsalmente, mas a coloração fica mais escura no primeiro ano. As nadadeiras são pequenas e reduzidas, com a parte inferior branca e a parte superior escura. Os golfinhos recém-nascidos medem cerca de 86 centímetros de comprimento e pesam cerca de 5 kg, ao passo que os adultos variam entre 2,18 e 2,5 metros e pesam aproximadamente de 60 a 100 kg. O maior peso registrado nessa espécie foi de 2,97 metros e 116 kg, em um macho. Geralmente, os machos crescem um pouco maiores que as fêmeas. Apesar de não existirem muitos estudos sobre o padrão reprodutivo da espécie, acredita-se que os machos atingem a maturidade sexual quando atingem comprimentos de 2,12 a 2,20 metros, enquanto as fêmeas atingem essa etapa com 2,06 a 2,12 metros ^{[1] [2] [3] [4] [5]}.

Distribuição Geográfica

Os golfinhos-lisos-do-sul possuem uma distribuição predominantemente circumpolar em todo o hemisfério sul, mas com ocorrências bem registradas na Nova Zelândia, no sudoeste da África, no sul do Brasil e ao longo da costa do Chile, com preferência por águas temperadas frias a subantárticas, com temperaturas variando entre 1 e 20°C. O limite preciso de sua ocorrência ainda não foi estipulado, devido a falta de estudos publicados, o limite sul da espécie parece ser limitado pela Convergência Antártica, ao passo que o limite norte parece limitado pela Convergência Tropical. Contudo, foram registrados avistamentos além desses limites, como em São Paulo ^[6]. A maioria dos avistamentos de golfinhos-lisos-do-sul ocorrem em águas profundas, em regiões onde a água se aproxima da costa e em áreas de ressurgência perto da costa ^{[7] [8] [9]}.

Ecologia e Comportamento

Os golfinhos-lisos-do-sul são considerados animais de grupo, com registros de agrupamentos de 1000 indivíduos, ainda que pequenos grupos de um a 10 também tenham sido relatados. Grupos pequenos associados a outras espécies de cetáceos também foram observados, o que comprova a pouca territorialidade na espécie. No Atlântico Sul, é muito comum encontrar grupos mistos com golfinhos-escuros (Lagenorhynchus obscurus), sendo relatados na Nova Zelândia, no sudoeste da África, no sul do Brasil e ao longo da costa do Chile. O comportamento e hierarquia dos grupos são classificados da seguinte forma: (1) agrupamentos sem subgrupos identificáveis e comportamento de creche, todos os adultos cuidam dos filhotes; (2) agrupamentos de subgrupos espalhados de diversos tamanhos; (3) agrupamentos em forma de V, semelhante ao de aves, seguindo o macho alfa e (4) rebanhos em formação de linha de coro, uma formação em linha dos indivíduos, em que eles nadam lado-a-lado, dispostos em fileiras. O movimento da espécie é muito caracterizado por se moverem saltando para fora da água continuamente. Quando nadam lentamente, expõem apenas uma pequena área da cabeça e das costas enquanto voltam à superfície para respirar. Em migrações, com viagens em altas velocidades, foi registrado comportamentos bem marcantes: (1) nadam logo abaixo da superfície, subindo brevemente para respirar e então submergem ou (2) nadam rapidamente na superfície, realizando saltos menores, cobrindo uma grande distância da superfície. Quanto aos padrões de forrageamento, os golfinhos-lisos-do-sul se alimentam de uma alta gama de peixes, dando preferência a peixes mesopelágicos e lulas, mergulhando a profundidades superiores a 200 metros em busca de alimento. Segundo pesquisas que analisaram o conteúdo estomacal de indivíduos da espécie, apresentam hábitos alimentares costeiros epipelágicos, mesopelágicos ou uma combinação de ambos ^{[10] [11]}. Foi observado que a espécie é ocasionalmente predada por tubarões maiores e orcas (Orcinus orca), mas outros predadores podem existir. Há um registro de 1983, em que um golfinho intacto de 86 centímetros foi encontrado no estômago de uma Merluza-negra (Dissostichus eleginoides) de 1,7 metro. Além disso, um feto foi descoberto dentro de um Tubarão-dorminhoco (Somniosus pacificus) em 1980, no Chile ^[12].

Ameaças e Conservação

Não existem registros de captura de golfinhos-lisos-do-sul vivos, como seria o caso se o objetivo fosse levá-los para cativeiro. Em estudos ao largo da costa oeste da África Austral, não foi encontrada evidência de captura acidental na pesca com redes de emalhar (rede que fica disposta verticalmente com iscas, para que os peixes fiquem presos na malha quando se movem para sair), mas pode haver competição por alimentos com a pesca de arrasto devido à dieta do animal depender muito de organismos de águas mais profundas. Os impactos diretos e indiretos da mudança climática global sobre a espécie são desconhecidos, ainda que possam ter um efeito em cascata sobre o movimento e a ecologia alimentar. Há ainda a hipóteses de sofrerem uma ameaça menor da atividade sísmica, seja para a busca de petróleo ou gás. Não há estimativas atuais de abundância e mortalidade global da espécie, embora seja considerada uma espécie bastante comum e abundante ao longo de sua distribuição, particularmente no Chile. A taxa de avistamento é considerada muito baixa, mas provavelmente esse resultado é observado por conta da falta de esforço de amostragem e devido às dificuldades de avistar os animais em seu habitat. Devido a bibliografia escassa, não existe muito consenso quanto ao seu status de conservação no cenário mundial. Segundo a Lista Vermelha de Mamíferos da África do Sul, Lesoto e Suazilândia de 2016, a espécie Lissodelphis peronii conta como LC (Least Concern, Pouco Preocupante). Já na Lista Nacional de Espécies do Chile, no Sistema de Classificação de Ameaças da Nova Zelândia e no Plano de Ação para Mamíferos Australianos, os golfinhos-lisos-do-sul são classificados como Deficientes de Dados (DD). Em 2001, a Lista Vermelha Global da IUCN classificava a espécie Lissodelphis peronii como Deficiente de Dados (DD), por conta das lacunas dos estudos em relação ao tema. Contudo, a classificação foi alterada em 2018, passando para o status de Pouco Preocupante (LC), devido à sua aparente ampla distribuição em águas pelágicas da região subantártica e à falta de evidências de ameaças severas às populações. Como a espécie ainda carece de mais dados em toda a sua distribuição, a classificação pode ser considerada provisória até que se saiba mais sobre a espécie ^{[13] [14] [15] [16]}.

Referências

Sydlig rätvalsdelfin eller sydamerikansk rätvalsdelfin (Lissodelphis peronii) är en art i familjen delfiner. Den förekommer i det öppna havet i den tempererade zonen på södra halvklotet. Utbredningsområdets norra gräns ligger ungefär vid 19 grad sydlig bredd.

Liksom den nordliga rätvalsdelfinen saknar arten ryggfena. Individerna är smala och upp till 3 meter långa. Honor blir vanligen upp till 2,3 meter långa. Vikten går upp till 300 kilogram. Nosen, fenor, kroppens sidor och buken är vita, alla andra kroppsdelar är svarta. Ungdjur har en grå färg eller fläckar på kroppen.

Sydlig rätvalsdelfin lever i grupper med upp till 100 individer.

Angående beståndet finns inga uppgifter och därför listas arten av IUCN med kunskapsbrist (data deficient).^[1]

Referenser

Den här artikeln är helt eller delvis baserad på material från tyskspråkiga Wikipedia, 16 februari 2010.

• R. Wandrey: Wale und Robben der Welt. Franckh-Kosmos Verlags Gmbh, 1997, ISBN 3-440-07047-6

1. ^ [a b] Lissodelphis peronii på IUCN:s rödlista, auktor: Hammond, P.S. et. al. (2008), besökt 18 februari 2010.

Güney gerçek balina yunusu (Lissodelphis peronii) Güney Yarımkürenin soğuk sularında yaşayan küçük ve ince bir memeli türü. İki gerçek balina yunusu türünden birisidir; Diğeri ise Kuzey Yarımkürenin derin okyanuslarında yaşayan kuzey gerçek balina yunusu'dur.

Açıklama

Güney gerçek balina yunusları.

Güney gerçek balina yunusu, dorsal yüzgeci olmayan bir yunus türüdür. Kuzey gerçek balina yunusundan daha küçük olmakla beraber başları ve yanları daha beyazdır. Alt tarafı beyaz, üst tarafı siyah, ince ve narin bir bedenleri vardır. Yüzgeçleri ağırlıklı olarak beyaz, küçük ve kavislidir. Kuyruklarının ortasında küçük bir çentik vardır ve arka kenarları iç bükeydir. Küçük ama belirgin bir gagaları vardır. Her iki çenede 43 ila 49 dişe sahiptirler.

Bu tür Güney Yarımkürede subtropik okyanuslardan subantartik okyanuslara kadar dağılım gösterirler. Toplam nüfus aralığı hakkında yeteri kadar çalışılmamıştır. Kuzey Amerikanın batı kıyılarında büyük nüfusa sahiptirler. Soğuk akıntılarla ilişkili olarak Afrika'nın batı ve güney kıyılarıyla beraber Namibya yakınlarında nüfus kaydedilmiştir.^[2][2][3]

Bu türü ilk defa 1804'te Bernard Germain de Lacépède tanımlamıştır. Lissodelphis cinsi, Balinaların okyanus yunusları ailelerinden, yunusgiller içerisinde yer alır.^[1] Bu cinsin adı Yunanca lisso (düz), ve delphis kelimelerinden türetilmiştir. Özel sıfat olan peronii , 1800'de Tazmanya seferi sırasında bu türleri gören François Péron anısına verilmiştir.^[4] Türün bilinen isimleri güney gerçek balina yunusu (right whale dolphin) ve yılan porpoisi'dir (snake porpoise).^[2][5]

Güney gerçek balina yunusları muhtemelen köpekbalıkları ve katil balinalar tarafından yenirler. L. peronii hangi balık türleriyle beslendiği tam olarak bilinmemekle beraber; kabuklular, kalamarlar ve ışıldakgiller türleri ile beslendikleri bilinmektedir. Diyetleri muhtemelen kril içerebilir.^[2]

Özellikleri

1847'de bir Fransız çizimi

Aerodinamik bir gövdeye, kısa tanımlı bir gagaya, görünür dişlere ve tek hava deliğine sahiptirler. Alt tarafları beyaz olmakla birlikte siyah-beyaz renklere sahiptirler. Dorsal yüzgeçleri bulunmamaktadır. Hızlı ve etkin yüzücülerdirler. Yeni doğanlar 80 ila 100 cm, yetişkinler ise 1.8 ila 2.9 m arasında uzunluklara sahiptirler. Dişiler erkeklerden biraz daha uzun olma eğilimindedirler. Yetişkin ağırlıkları 60–100 kg arasındadır. Balık kalamar ve ahtapot yerler.

Davranışları

Güney gerçek balina yunusları oldukça narindirler ve sürekli olarak su yüzeyine sıçrayarak hareket ederler. Yavaş yüzerlerken, baş ve arkalarının arasındaki küçük bir alan olan solunum yüzeyi gözlemlenebilir. Genelde 2 ila 100 arası üyeden oluşan gruplar halinde yaşarlar. Bazı gruplar diğerlerine göre daha agresiftirler ve bot ve teknelerden uzakta yüzerler, diğerleri ise yay yüzüşü tarzında bot ve teknelere yakın yüzebilirler. Bu yay yüzüşü, 19. yüzyılda zıpkınlı balina avcıları tarafından onların aleyhinde kullanılmıştır. Güney gerçek balina yunusları genellikle kum saati yunusları ile beraber görülürler.

Koruma

Güney gerçek balina yunusları, Batı Afrika Makronezyası Küçük Deniz Memelileri ve Denizanalarını Korumayla ilgili Mutabakat ve (Western African Aquatic Mammals MoU)^[6] ve Pasifik Adası Bölgesi Deniz Memelilerini ve Yaşam Alanlarını Koruma ile ilgili Mutabakat kapsamındadır (Pacific Cetaceans MoU).^[7]

Ayrıca bakınız

• Balina ve yunuslar listesi
• Deniz biyolojisi

Kaynakça

• {{{assessors}}} (2008). Lissodelphis peronii. IUCN 2008. IUCN Nesli Tükenme Tehlikesi Altında Olan Türlerin Kırmızı Listesi. Erişim tarihi: 6 March 2009.

Dış bağlantılar

• Balina ve Yunus Koruma Topluluğu

• 1 Опис
• 2 Поширення
• 3 Поведінка
• 4 Відтворення
• 5 Загрози та охорона
• 6 Джерела

Lissodelphis peronii là một loài động vật có vú trong họ Delphinidae, bộ Cetacea. Loài này được Lacépède mô tả năm 1804.^[2]

Hình ảnh

Chú thích

Tham khảo

Liên kết ngoài

Phương tiện liên quan tới Lissodelphis peronii tại Wikimedia Commons

Bài viết liên quan đến Bộ Cá voi (Cetacea) này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn.

• x
• t
• s

남방고추돌고래 또는 흰배고추돌고래(Lissodelphis peronii)는 남반구의 한랭 해역에서 발견되는 고래하목 참돌고래과의 작은 해양 포유류이다.^[3] 고추돌고래속에 속하는 2종의 돌고래 중의 하나로, 북방고추돌고래는 북반구의 심해에서 발견된다.

각주