Analysis of stomach contents of the whitespotted bamboo shark, Chiloscyllium plagiosum in the northern waters off Taiwan

• Main Authors: Lin, Yu-Han, 林玉涵
• Other Authors: Joung, Shoou-Jeng
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/12156242523544071235

碩士 === 國立臺灣海洋大學 === 環境生物與漁業科學學系 === 104 === The whitespotted bamboo shark (Chiloscyllium plagiosum) is a dominant small shark species in the northern waters of Taiwan and it plays an important role in the benthic ecosystem in this region. However, the feeding ecology of this species is still limited. Therefore, the objective of this study was to examine the feeding habits of whitespotted bamboo shark in the northern Taiwan waters, based on 327 specimens (126 females, 201 males) collected at Fu-Chi fish market in New Taipei city from October 2013 to March 2015. Of the specimens, 120 stomachs were empty and the stomach empty rate was 36.7 %. A total of 14 prey taxa were identified, including the Demospongidae (% IRI=40.69%), followed by Unidentified prey (21.54%), Polychaeta (18.10%), Macrua (10.56%), Osteichthyes (5.88%), Cephalopoda (1.7%), Anopla (0.56%), Onuphidae (0.54%), Eunicidae (0.19%), Gastropoda (0.12%), Brachyura (0.09%), Okamejei acutispina (0.02%), Anomura (0.01%), and Florideophyceae (0.004%). The intraspecies diet composition may vary due to many factors, including different life stages, sex, seasons, and fishing gears. In this study, ontogenetic change for whitespotted bamboo shark was found. Immature individuals feed more on crustaceans, while mature individuals prefer teleost fishes. Mature females were more active in feeding before mating and spawning period, they fed on cephalopods, teleost, sponges, and polychaetes, this behavior may help whitespotted bamboo shark save energy for reproduction. There was no significant difference on prey composition by fishing gears and seasons, but the major prey item varied by season. In the spring, unidentified prey and polychaete were the main prey item; in the summer, the polychaetes was the dominated prey item; in the fall, sponge and a small amount of teleost were found; in the winter whitespotted bamboo sharks mainly fed on sponges and unidentified prey, but the proportion of crustaceans increased. In sum, whitespotted bamboo sharks mainly feed on benthic prey species, but the diet of this shark varied by mature stages, sex, habitat, and seasons.