碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 104 / Fisheries is an important pathway for getting food resources for human. Meanwhile, global production of cephalopod fishery, that is at lower trophic level in marine ecosystem, was gradually increased in the past 40 years, and was suggested as one of the sustainable marine species for fishery. Neritic squids was one of the main target species for torch light net and trawl fisheries off Taiwan, while more detailed research was done for Uroteuthis edulis in south china sea, but rather scare in Taiwan Strait. The Penghu was one of the important fishing grounds for trawl fishery around Taiwan Strait, with fluctuated marine environment by season. Therefore, the objectives of this study are: (1) to study the neritic squid species composition in the fishery and its seasonal variation; (2) to explore the life-history traits of the dominant species. The samples of neritic squids were monthly collected from a trawl vessel in Suogang port, from October 2013 to April 2015 (except April 2014). The trawl vessel was fishing in surrounding waters of Chimei island. Species was identified according to the morphometrics including fin length, luminescent organ, sucker ring morphology of tentacles and third arm. A total of 2260 individual (88kg) of neritic squids was collected, and 5 squid species were identified. Species diversity was higher in spring and autumn. Dominant species were Uroteuthis chinensis and U. edulis. Species composition varied by season in Taiwan Strait, that U. chinensis appeared year round, while U. edulis appeared higher in warm water season. U. chinensis with growth and maturation significant differences between sexes. The maximum length of male was 26 cm, maximum age of 193 days, the maximum length of females was 21 cm, maximum age of 175 days. Female was larger than male when mature (F: 181mm; M: 171mm). Female GSI was higher than the male. Main spawning period was in November-January and July. By back-calculating using statolith growth increment analysis, distinct two spawning groups were found, that the U. chinensis composed by spring cohort (SC: January to May) and autumn cohort (AC: July to December). For females, SC growth rate and mature rate was greater than SC (SC: 167d; AC: 209d), matured at larger size than AC (SC: 186mm; AC: 154mm). For males, SC growth rate and mature rate was greater than SC (SC: 178d; AC: 184d), matured at larger size than AC (SC: 203mm; AC: 131mm). ML and BW of the growth mode, SC best fitted to linear growth, AC best fitted to Gompertz growth function. U. edulis distributed between January to June, no significant differences between sexes. Both female and males’ maximum ML was 14 cm. Spawning period was in March and April. Results showed growth differences with the Southern East China Sea population. Seasonal changes in the Taiwan Strait may change neritic squids species composition and growth mode related to marine environmental factors.
| Identifer | oai:union.ndltd.org:TW/104NTOU5451001 |
| Date | January 2015 |
| Creators | Chiu, Chun-Kai, 邱群凱 |
| Contributors | Chen, Chih-Shin, Wang, Chia-Hui, 陳志炘, 王佳惠 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 66 |
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