科研之友
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摘要
Age, growth, sex and gonadal maturation of the shanny, Liphorys pholis, were determined in specimens caught in a rocky intertidal area in northern Portugal in order to provide essential ecological data on the species. This study represents the first available reference in the literature for L.pholis in a southern European location. Totals of 251 individuals (115 females, 99 males, 37 undetermined; total length: 30-172mm) were collected seasonally (November 2013, March, June, and September 2014) in a northern Portuguese rocky beach (Povoa do Varzim: 41 degrees 2347.79N; 08 degrees 4645.48W) using fine-mesh aquarium fishnets during low tides. Marginal increment analysis showed that one translucent and one opaque zone was formed each year in the sagittal otoliths. Ages of L.pholis ranged from 0 to 6years. Males were larger and older than females. The von Bertalanffy growth equation parameters considering all individuals were L=184mm, K=0.26mm/year, t(0)=-1.34. The annual variation of the fish condition and hepatosomatic indexes appeared to be related to the mobilization of the somatic reserves prior to reproduction. Maximum gonadosomatic index for males and females coincided with the breeding seasons (November and March). The sex ratio was close to 1:1, all maturity stages included. Furthermore, some stages of sexual development in males and females were observed during the same season, and several germinal cells were also observed at the same time within a single ovary or testis, indicating that L.pholis is an asynchronous and multiple spawner. Maturation for both sexes appears to be around 70mm TL and prior to reaching 1year of age.
- 出版日期2017-4
