Simple nutritional condition indicators are needed to provide information on the influence of ecosystem changes on the populations of the American lobster Homarus americanus (H. Milne Edwards, 1837) on various timescales. This study validates the use of the water content (% wet mass) of the digestive gland as an indicator of nutritional condition in the lobster (carapace length 65–127 mm) by assessing its capacity to estimate digestive-gland lipid reserves under variable environmental and physiological conditions. The validation was completed using samples from wild lobsters dissected shortly after being captured during different seasons and in various locations in the St. Lawrence Estuary and Gulf of St. Lawrence (GSL), and data from an environmentally realistic laboratory study on post-ovigerous females from the southern and the northern GSL sampled at different stages of their molt cycle. In both wild and experimental lobsters, water content was the best predictor of lipid reserves compared to other condition indicators (i.e., condition factor, various digestive-gland indices, and hemolymph Brix index). A strong linear relationship was found between lipid and water contents. Lipid content and interrelated molting status were identified as two important factors leading to the variations in water-fat regression equations among groups of wild or experimental lobsters. As lipid content could vary spatiotemporally in unexpected ways in a changing environment, it is recommended to use a sampling event-specific regression line to estimate digestive-gland lipid content from measured water content in field monitoring programs. Combining water content with molt status indicators such as Brix index is recommended to support interpretation of the observed variations in condition.

中文翻译：

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消化腺含水量作为美国龙虾 Homarus americanus 营养状况指标的验证（H. Milne Edwards，1837）（十足目：Nephropidae）

需要简单的营养状况指标来提供有关生态系统变化在不同时间尺度上对美国龙虾 Homarus americanus (H. Milne Edwards, 1837) 种群影响的信息。本研究通过评估其在可变环境和条件下估计消化腺脂质储备的能力，验证了使用消化腺的含水量（湿重百分比）作为龙虾（甲壳长度 65-127 毫米）营养状况的指标。生理条件。验证是使用在不同季节和圣劳伦斯河口和圣劳伦斯湾 (GSL) 的不同地点捕获后不久解剖的野生龙虾样本完成的，以及来自环境现实实验室研究的数据，该研究对来自南部和北部 GSL 的产卵后雌性在其蜕皮周期的不同阶段进行了采样。在野生龙虾和实验龙虾中，与其他条件指标（即条件因素、各种消化腺指数和血淋巴白利糖度指数）相比，水含量是脂质储备的最佳预测指标。发现脂质和水含量之间存在很强的线性关系。脂质含量和相关的蜕皮状态被确定为导致野生或实验龙虾群之间水-脂肪回归方程变化的两个重要因素。由于脂质含量在不断变化的环境中可能会以意想不到的方式随时间变化，建议使用采样事件特定的回归线来估计现场监测计划中测量的水含量的消化腺脂质含量。建议将水分含量与白利糖度指数等蜕皮状态指标相结合，以支持对观察到的条件变化的解释。