Abstract

Water temperature is an important abiotic component in farmed and wild crayfish habitats as it influences individual and population characteristics including growth, metabolic activity, and overall population vigor. Thermal limits, however, have not been established for the two commercially important crayfishes in Louisiana, the red swamp crayfish Procambarus clarkii (Girard, 1852) and the southern white river crayfish P. zonangulus (Hobbs & Hobbs, 1990). We aimed to determine the thermal stress responses for the two species. Thermal stress was examined by the critical thermal maxima (CT_max) for crayfish acclimated to 24, 27, or 30 °C for two weeks prior to experimentation. Water temperature in all acclimation trials was increased 1 °C h^–1 and the end-point temperature for an individual was determined by the failure of righting response within 30 seconds. CT_max values (±SD) for P. clarkii acclimated at 24, 27, and 30 °C were 39.5 ± 0.5, 39.1 ± 0.3, and 39.4 ± 0.7 °C respectively, and 39.8 ± 0.8, 38.8 ± 0.8, and 39.0 ± 0.6 °C for P. zonangulus. CT_max did not differ significantly between species in any of the acclimation treatments. Thermal stress was also examined by measuring P. clarkii and P. zonangulus hemolymph glucose concentration every two hours for crayfish acclimated at 26 °C for two weeks and water temperature increased 1 °C h^–1. Hemolymph glucose concentration began to increase at 36 °C in P. zonangulus and 38 °C in P. clarkii. Large increases in mean hemolymph glucose concentration (±SE) were observed in both P. clarkii (67.19 mg^–dl ± 24.55) and P. zonangulus (74.11 mg^–dl ± 18.04) at 40 °C.

中文翻译：

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路易斯安那州的两个同伴小龙虾的热应激反应，Procambarus clarkii Girard，1852年和Procambarus zonangulus Hobbs＆Hobbs，1990年（十足目：Astacoidea：Cambaridae）

摘要

水温是养殖和野生小龙虾栖息地中重要的非生物成分，因为它会影响个体和种群特征，包括生长，代谢活动和总体种群活力。然而，尚未为路易斯安那州的两个商业上重要的小龙虾，红色沼泽小龙虾Procambarus clarkii（吉拉德，1852年）和南部白河小龙虾P. zonangulus（Hobbs＆Hobbs，1990年）建立温度极限。我们旨在确定两个物种的热应力响应。在实验前的两周内，通过适应于24、27或30°C的小龙虾的临界热最大值（CT _max）检查了热应力。所有适应性试验中的水温均升高1°C h^–1和个人的端点温度由30秒内的纠正响应失败确定。克拉克疟原虫在24、27和30°C适应的CT_最大值（±SD）分别为39.5±0.5、39.1±0.3和39.4±0.7°C和39.8±0.8、38.8±0.8和39.0±松果虾（P. zonangulus）为0.6°C 。在任何驯化处理中，物种之间的CT _max均无显着差异。通过在26°C适应了两周的小龙虾和水温每升高1°C h ^{–1的情况}下，每两小时测量克拉克疟原虫和松果疟原虫的血淋巴葡萄糖浓度，来检查热应激。。血淋巴葡萄糖浓度开始在增加在36℃ P. zonangulus和38℃下，在克氏原螯。在40°C时，克拉克疟原虫（67.19 mg ^–dl ±24.55）和松果疟原虫（74.11 mg ^–dl ±18.04）均观察到平均血淋巴葡萄糖浓度（±SE）大大增加。