dcsimg

Diagnostic Description

provided by Fishbase
Obscure saddle markings on body and precaudal tail, and with dark markings on the terminal and hypural caudal-fin lobes (Ref. 11146).
license
cc-by-nc
copyright
FishBase
Recorder
Cristina V. Garilao
original
visit source
partner site
Fishbase

Life Cycle

provided by Fishbase
Oviparous, with a single egg laid per oviduct (Ref. 244). Embryos feed solely on yolk (Ref. 50449).
license
cc-by-nc
copyright
FishBase
Recorder
Cristina V. Garilao
original
visit source
partner site
Fishbase

Morphology

provided by Fishbase
Dorsal spines (total): 0; Dorsal soft rays (total): 0; Analspines: 0; Analsoft rays: 0
license
cc-by-nc
copyright
FishBase
Recorder
Cristina V. Garilao
original
visit source
partner site
Fishbase

Biology

provided by Fishbase
A little-known, but very common shark, found in deep water near the bottom (Ref. 11146). Maximum length of at least 40 cm TL, probably reaching 50 cm (Ref. 11146).
license
cc-by-nc
copyright
FishBase
Recorder
Kent E. Carpenter
original
visit source
partner site
Fishbase

Importance

provided by Fishbase
fisheries: minor commercial; price category: low; price reliability: very questionable: based on ex-vessel price for species in this family
license
cc-by-nc
copyright
FishBase
Recorder
Kent E. Carpenter
original
visit source
partner site
Fishbase

分布

provided by The Fish Database of Taiwan
分布於西太平洋區,由日本至東海,可能至越南、菲律賓。台灣分布於北部及東北部海域。
license
cc-by-nc
copyright
臺灣魚類資料庫
author
臺灣魚類資料庫

利用

provided by The Fish Database of Taiwan
主要以底拖網捕獲,一般捕獲魚體較小,故以下雜魚處理,偶有人加工成醃燻製品。
license
cc-by-nc
copyright
臺灣魚類資料庫
author
臺灣魚類資料庫

描述

provided by The Fish Database of Taiwan
體型修長,近似圓柱形或稍縱扁。頭平扁,頭寬大於頭高;尾部細長側扁。吻端呈窄拋物線。眼大,橢圓形,下眼瞼上部分化成瞬褶,瞬褶下方具一深溝。鼻孔斜列,位於口前,前鼻瓣具一個三角形突出,無鼻鬚;無口鼻溝。口寬大,弧形,口閉時齒暴露;上下唇褶發達;齒細小,5-7齒尖型,多行使用。噴水孔小,新月形,位於眼後。盾鱗細如絨化,3棘突3脊突。背鰭2個,小型,大小和形狀略同,第一背鰭起點與腹鰭基底後端相對;臀鰭低而延長,內角突出,未達第二背鰭下角後方;腹鰭大於背鰭;胸鰭寬而圓;尾鰭狹長,上緣具2縱行鋸齒狀大鱗,上葉頗發達;尾鰭下葉前部不顯著突出,與中部連合呈倒三角形,中部與後部間有一缺刻,後部與上葉相連呈圓形。體褐色,體背具不顯著之鞍狀暗斑;背、尾鰭後端白色。
license
cc-by-nc
copyright
臺灣魚類資料庫
author
臺灣魚類資料庫

棲地

provided by The Fish Database of Taiwan
棲息於較深水域的底棲性魚類,生態習性了解不多。
license
cc-by-nc
copyright
臺灣魚類資料庫
author
臺灣魚類資料庫

Gecko catshark

provided by wikipedia EN

The gecko catshark (Galeus eastmani) is a species of catshark, part of the family Scyliorhinidae, native to the northwestern Pacific Ocean from southern Japan to Taiwan, and possibly also off Vietnam. It is a common, demersal species found at depths of 100–900 m (330–2,950 ft). Its body is slender, with a pattern of dark saddles and blotches. The dorsal and caudal fins are edged in white, and there is a prominent crest of enlarged dermal denticles along the dorsal edge of the caudal fin. The gecko catshark is a schooling, opportunistic predator of bony fishes, cephalopods, and crustaceans. It is oviparous, with females producing two vase-shaped egg capsules at a time. This species is captured as bycatch, but does not appear to be threatened by fishery activities at present and has been assessed as Least Concern by the International Union for Conservation of Nature (IUCN).

Etymology

Although the honor for this Catshark is not named, it is possibly in honor of fish paleontologist Charles Rochester Eastman (1868-1918).[2]

Taxonomy and phylogeny

The first known specimen of the gecko catshark, a 35 cm (14 in) long female caught off the Izu Peninsula of Japan, was presented to American ichthyologists David Starr Jordan and John Otterbein Snyder by Alan Owston, a shipmaster from Yokohama. Jordan and Snyder described the species as Pristiurus eastmani in a 1904 volume of the scientific journal Smithsonian Miscellaneous Collections.[3] Later authors have recognized Pristiurus as a junior synonym of Galeus.[4] A 2005 phylogenetic analysis, based on mitochondrial and nuclear DNA, found that this species, G. gracilis, and G. sauteri form a clade apart from G. melastomus and G. murinus.[5]

Distribution and habitat

The range of the gecko catshark extends from southern Japan, where it occurs off the Shizuoka and Mie Prefectures of Honshu and the main islands of Shikoku and Kyushu, to the East China Sea including Taiwan. It is extremely abundant in Japanese waters. Further records from off Vietnam may be erroneous. This species is found in water 100–900 m (330–2,950 ft) deep, on or close to the sea floor.[1][4] It seems to exhibit strong spatial segregation by sex.[4][6]

Description

Attaining 40 cm (16 in), possibly 50 cm (20 in) in length, the gecko catshark has a slim, firm body and a fairly short head that comprises less than one-fifth of the total length. The snout is flattened with a blunt tip. The nostrils are large and divided by triangular flaps of skin on their anterior rims. The eyes are large and horizontally oval, with rudimentary nictitating membranes (protective third eyelids) and indistinct ridges underneath. The mouth is sizable and forms a long arch; there are well-developed furrows around the corners. The teeth are small and number around 47 rows in the upper jaw and 50 rows in the lower jaw; each has a narrow central cusp and typically two pairs of smaller cusplets on the sides. The five pairs of gill slits are short, with the fourth pair about level with the pectoral fin origins.[4][6][7]

The first dorsal fin has a blunt apex and is positioned over the latter half of the pelvic fin bases. The second dorsal fin resembles the first but is slightly smaller, and is positioned over the latter third of the anal fin base. The pectoral fins are rather large and broad, with rounded corners. The pelvic fins are small with angular margins; the claspers of adult males are short and do not reach the anal fin. The anal fin base measures roughly 12% of the total length, shorter than the distance between the dorsal fins but longer than the distance between the pelvic and anal fins. The caudal peduncle is almost cylindrical, and leads to a low caudal fin with a subtle lower lobe and a ventral notch near the tip of the upper lobe. The skin is covered by small, overlapping dermal denticles; each has a leaf-shaped crown with a horizontal ridge and three marginal teeth. There is a crest of enlarged denticles along the upper edge of the caudal fin. This species is grayish above and patterned with darker, fuzzy-edged saddles and blotches along the body and tail. The underside, dorsal and caudal fin trailing margins, and interior of the mouth are white.[4][6]

Biology and ecology

Schooling in nature,[6] the gecko catshark feeds opportunistically on a wide variety of bony fishes (including lanternfish), cephalopods (including sepiolid and enoploteuthid squid), and crustaceans (including isopods, amphipods, krill, and decapods). The relative importance of the three prey categories varies between geographical areas and seasons, likely reflecting what is most available in the environment.[8] This species is oviparous; adult females have a single functional ovary, on the right, and two functional oviducts. A single egg matures within each oviduct at a time.[8] Mature eggs are contained within smooth, translucent yellow, vase-shaped capsules measuring roughly 6 cm (2.4 in) long and 1.6 cm (0.63 in) across, with the top squared off and the bottom converging on a short projection.[4][6] One study in Suruga Bay recorded females with large yolked ova inside the ovary year-round, but females in the western part of the bay were only found to carry egg cases from October to January, suggesting that the interval between egg depositions is shorter at that time.[8] Males and females attain sexual maturity at approximately 31–32 cm (12–13 in) and 36–37 cm (14–15 in) long respectively. However, there is a Taiwanese record of an immature male 38 cm (15 in) long.[1]

Human interactions

Uncertain numbers of gecko catsharks are caught incidentally by commercial trawl fisheries. In Taiwan, it is occasionally brought to market and processed into fishmeal for aquacultural use. This species' small size and oviparous mode of reproduction may make it more resilient to fishing pressure than other sharks. As the gecko catshark remains common off Japan and may be protected from fishing in the deeper parts of its range, the International Union for Conservation of Nature (IUCN) has assessed it as of Least Concern.[1]

References

  1. ^ a b c d Rigby, C.L.; Chen, X.; Ebert, D.A.; Herman, K.; Ho, H.; Hsu, H.; Zhang, J. (2020). "Galeus eastmani". IUCN Red List of Threatened Species. 2020: e.T161364A124472336. doi:10.2305/IUCN.UK.2020-3.RLTS.T161364A124472336.en. Retrieved 19 November 2021.
  2. ^ Christopher Scharpf & Kenneth J. Lazara (22 September 2018). "Order CARCHARHINIFORMES (Ground Sharks): Families PENTANCHIDAE, SCYLIORHINIDAE, PROSCYLLIIDAE, PSEUDOTRIAKIDAE, LEPTOCHARIIDAE, TRIAKIDAE, HEMIGALEIDAE, CARCHARHINIDAE and SPHYRNIDAE". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 10 March 2022.
  3. ^ Jordan, D.S.; J.O. Snyder (April 11, 1904). "On a collection of fishes made by Mr. Alan Owston in the deep waters of Japan". Smithsonian Miscellaneous Collections. 45: 230–240.
  4. ^ a b c d e f Nakaya, K. (1975). "Taxonomy, comparative anatomy and phylogeny of Japanese catsharks, Scyliorhinidae". Memoirs of the Faculty of Fisheries, Hokkaido University. 23: 1–94.
  5. ^ Iglésias, S.P.; G. Lecointre & D.Y. Sellos (2005). "Extensive paraphylies within sharks of the order Carcharhiniformes inferred from nuclear and mitochondrial genes". Molecular Phylogenetics and Evolution. 34 (3): 569–583. doi:10.1016/j.ympev.2004.10.022. PMID 15683930.
  6. ^ a b c d e Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Food and Agricultural Organization. p. 311. ISBN 92-5-101384-5.
  7. ^ Compagno, L.J.V. (1988). Sharks of the Order Carcharhiniformes. Blackburn Press. p. 433. ISBN 1-930665-76-8.
  8. ^ a b c Horie, T.; S. Tanaka (2000). "Reproduction and food habits of two species of sawtail catsharks, Galeus eastmani and G. nipponensis, in Suruga Bay, Japan". Fisheries Science. 6 (5): 812–825. doi:10.1046/j.1444-2906.2000.00133.x.
license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN

Gecko catshark: Brief Summary

provided by wikipedia EN

The gecko catshark (Galeus eastmani) is a species of catshark, part of the family Scyliorhinidae, native to the northwestern Pacific Ocean from southern Japan to Taiwan, and possibly also off Vietnam. It is a common, demersal species found at depths of 100–900 m (330–2,950 ft). Its body is slender, with a pattern of dark saddles and blotches. The dorsal and caudal fins are edged in white, and there is a prominent crest of enlarged dermal denticles along the dorsal edge of the caudal fin. The gecko catshark is a schooling, opportunistic predator of bony fishes, cephalopods, and crustaceans. It is oviparous, with females producing two vase-shaped egg capsules at a time. This species is captured as bycatch, but does not appear to be threatened by fishery activities at present and has been assessed as Least Concern by the International Union for Conservation of Nature (IUCN).

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN