阿根廷滑柔鱼雌性个体生殖能量积累及环境效应关系

Reproductive energy accumulation and environmental effects in female Argentinean shortfin squid, Illex argentinus

阿根廷滑柔鱼(Illex argentinus)终生一次繁殖产卵,生殖能量积累影响个体繁殖力和后代存活率。为获知该种类雌性个体生殖能量积累及与栖息海域环境的关系,根据2019—2020年在西南大西洋海域采集的阿根廷滑柔鱼样本,采用组织能量密度测定技术和广义加性混合效应模型(generalized additive mixed-effects models, GAMM),分析了卵巢、输卵管和缠卵腺等组织的能量密度和能量积累变化,及与海表面温度(sea-surface temperature, SST)和叶绿素a(chlorophyll-a,Chl.a)质量浓度之间的效应关系。结果显示,不同性腺发育时期卵巢组织能量密度差异显著,输卵管和缠卵腺组织能量密度无显著变化。随着性腺发育,卵巢、输卵管和缠卵腺组织的能量积累逐渐增加但在繁殖产卵期呈下降趋势。SST对卵巢和缠卵腺等组织能量密度具有显著的效应关系,卵巢组织能量密度随SST升高而增加,缠卵腺组织能量密度则呈下降趋势;而且,SST对卵巢组织能量积累产生显著的负效应关系。Chl.a质量浓度对卵巢和输卵管的组织能量密度产生正效应关系,并且影响卵巢和缠卵腺的组织能量积累。研究表明,阿根廷滑柔鱼雌性个体的生殖能量积累在繁殖产卵期之前持续积累且增加显著,SST和Chl.a质量浓度对卵巢、输卵管和缠卵腺的组织能量密度及能量积累具有显著的效应关系,但是影响作用存在组织特殊性。

Argentinean shortfin squid, Illex argentinus, is one of the most important world fishery species characterized by semelparous reproduction, where the reproductive energy accumulation significantly links to the reproductive potential and the survivorship of hatchlings. To better understand the female’s reproductive energy accumulation and the responsive relation to their living environments, we randomly sampled squid specimens from southwest Atlantic during 2019 and 2020, and applied the technique of tissue energy density determination to determine the energy density of reproductive tissues, namely ovary, oviducts and nidamental glands, and then to estimate the tissues’ energy accumulation. We also applied the generalized additive mixed-effects models(GAMM) to investigate the relationships between reproductive tissues’ energy density, energy accumulation and sea surface oceanic variables, namely sea surface temperature(SST) and chlorophyll a concentration(Chl.a). The results indicated that during the period of sexual maturation, the ovary energy density varied significantly, but both oviducts and nidamental glands did not show significant differences in the energy density with sexual maturation. In terms of energy accumulation, all of the three tissues showed an increasing trend till spawning. The energy density of ovary and nidamental glands was found in significant relation to SST, where the ovary energy density increased with increasing SST when SST was higher than 11℃, while the nidamental glands density declined with increasing SST. However, it was found that only ovary energy accumulation was significantly correlated with SST, declining with increasing SST. Regarding chlorophyll-a concentration, there were significantly positive correlations between ovary energy density, oviducts energy density and Chl.a, indicating positive effects of primary production on both tissues’ energy density. Additionally, there were also significant effects of Chl.a on the energy accumulation of both ovary and nidamental glands. Cumulatively, the female Argentinean shortfin squid accumulated reproductive energy continuously till spawning, and the energy density and energy accumulation of the reproductive tissues were significantly correlated with SST and Chl.a, but the effects on the energy density and energy accumulation from the sea surface oceanic variables were likely to be tissue-specific.