Not assigned |
Testudines |
Cheloniidae
環境：環境 / 気候帯 / 深さの範囲 / 分布範囲
生態学
底生の漂泳性; 深さの範囲 0 - 200 m (参照 78527). Tropical; 61°N - 40°S, 130°W - 160°E (参照 1397)
Indo-Pacific and the Atlantic Ocean.
初回成熟時の長さ / サイズ / 重さ / 年齢
成熟: Lm ?, range 49 - ? cm Max length : 76.0 cm CL オス/雌雄の選別がない; (参照 418); common length : 75.0 cm CL オス/雌雄の選別がない; (参照 1397); 最大公表体重: 43.4 kg (参照 1397)
The olive ridley turtle has a slightly deeper body than the Kemp’s ridley. In adults; carapace nearly round; upturned on the lateral margins; flat on top; its width 90 percent of its length (Straight Curved Length (SCL)). Head: subtriangular; moderate-sized; averaging 22.4 percent of straight carapace length (SCL). Hatchlings: relatively bigger heads (39 percent SCL); longer carapaces (width 78 percent SCL); flippers comparatively bigger than in adults. In 3-year old juveniles: the carapace width, 93 percent of SCL; head length, 26 percent of SCL. Scales and scutes: same configuration as in the Kemp’s ridley; but the lateral scutes are often more than five pairs; the first pair is always in touch with the precentral scute. Also has openings of the Rathke’s glands on the plastral bridges; through a pore on the rear part of each inframarginal scute Fore flippers with 1 or 2 visible claws on the anterior border; sometimes another small claw in the distal part; rear flippers also with 2 claws. Males: larger more strongly curved claws; as well as a longer tail. Color: adults, plain olive-grey above; creamy or whitish; with pale grey margins underneath. Newborn hatchlings: when wet; almost completely black; sometimes with greenish sides; in general, become dark grey after drying. With growth; they change to grey dorsally and white underneath.
This species is the most abundant sea turtle in the world. Frequently neritic, usually migrates along the continental shelves and feeds in shallow waters (Ref. 1397) but also dives deeper than 150 m (Ref. 78527). Shallow coastal waters; open sea forming schools (Ref. 417). Habitat is a warm vertically stratified water with deep thermocline (Ref. 78527). Observed to be basking on sand beaches (Ref. 1397). Nesting patterns range from solitary to small groups to arribadas (Ref. 97534). Little information exists on the feeding behavior of post-hatchlings and juveniles in pelagic waters, but they are most likely exclusively carnivorous, consuming, for instance, invertebrates and fish eggs. Older juveniles and adults feed on a wide variety of benthic organisms (Ref. 122680).
ライフサイクルと交尾行動
成熟 | 繁殖 | 放精 | 卵 | 生産力 | 幼生
Mating occurs before and during nesting season near nesting beaches, along migratory routes or at the sea surface. When disturbed, they dive. It is assumed that promiscuity may occur but was not yet reported. Nesting season occurs in summer and autumn but varies from place to place. The reproductive cycle is almost annual which occurs every 14 or 28 days and repeats two to eight times per season. The mean number of eggs per clutch is around 109 eggs which usually ranges from a couple of dozen to more than 155 eggs. Incubation period extends from 45 to 65 days. Egg mean diameter ranges from 3.21 to 4.47 cm and 30 to 38 g in weight. Hatchlings ranges between 3.47 and 4.46 cm straight carapace length and from 12 to 22.3 g in body weight. Sizes and weight varies in different populations and localities (Ref. 1397). Temperature-dependent Sex Determination (TSD) is demonstrated in this species (Refs. 83974, 83976).
主な参考文献
参考文献 | コーディネーター | 協力者
Hirth, H.F. 1993 Chapter 10. Marine turtles. pp. 329-370. In A. Wright and L. Hill (eds) Nearshore marine resources of the South Pacific. Forum Fisheries Agency (Honiara), Institute of Pacific Studies (Suva) and International Centre for Ocean Development (Canada), 710 p. (参照 97534)
IUCNのレッドリストの状況は
(参照 130435: Version 2025-2 (Global))
脆弱 (VU) (A2bd); Date assessed: 30 June 2008
ワシントン条約ステータス (参照 108899)
人間に対する脅威
人間の用途
水産業: 商業
FAO - Publication: search | FishSource | 私達の周りの海
用具
インターネットの情報源
モデルに基づく推定値
回復力
(Ref. 69278): |
手段, １．４年～４．４年の倍増期間の最小個体群 (K=0.14-0.18; tm=8) |
漁業の脆弱性
(参照 71543) |
High to very high vulnerability (70 of 100). |
価格帯
(参照 80766): |
Unknown. |
