The effects of temperature and substrate on ontogenetic behavior of bastard halibut, Paralichthys olivaceus (T. et S.)

The effects of temperature and substrate on ontogenetic patterns and settlement behavior of bastard halibut, Paralichthys olivaceus (T. et S.) were studied in a series of laboratory experiments. Analysis on stage-based data revealed that except for settlement, and compared to the substrate, the ambient temperature dominantly controlled the hatch success and subsequent development of the species. The oosperm optimum survival rate of 60% during hatching occurred at 20℃, and survival rate of 29%, at 18℃ for larval rearing. The survival rate of larvae reared under variable temperature of 3.5–4.5℃ was higher than that of those reared under stable temperature. The maximum survival rate of 29%, corresponded to variation at temperature of 4℃. With increase in age newly settled juveniles preferred to lie on the fine substrate and gradually moved on the coarse substrate. GLM (general linear model) analysis showed that the combination of temperature and substrate had no significant impact on the survival of settling larvae, but definitely affected the duration of settlement.

温度对褐牙鲆资源补充特征的生态效应

根据1980－1995年胶州湾和渤海水域资源生态学调查资料，采用自然生态学与实验生态学相结合的方法，综合分析温度对褐牙鲆补充阶段生活史特征及其资源补充过程的影响。结果表明，随地理纬度的增加，褐牙鲆产卵期滞后，生殖季节缩短；在水温从9.62℃增至1989℃的过程中，褐牙鲆的性腺发育指数（GSI）出现单一峰值，7月至翌年3月间此值均小于1.0;在实验水温范围（7－27℃）内，受精卵孵化时数（t）随水温（T）变化关系为ｔ＝292．84e－0.0968T（r=－0．8645，n=34,p＜0．O01）。在一定温度范围内，亲鱼性成熟、排卵、仔鱼变态速度与温度呈正相关；胚胎发育总时数、孵化率、仔鱼各发育阶段的持续时间和仔鱼变态持续时间、仔鱼变态后的个体大小与温度呈负相关;仔幼鱼生长速度与温度呈二项式曲线；褐牙鲆卵的温度容忍度至少为8℃，其仔鱼、幼鱼生长率与存活率均为最低。