Diets of four shrimp species in eelgrass habitats, Western Port Bay, Victoria

This study examined stomach contents of shrimp sampled in the beam trawls in Western Port Bay from July 1977 to January 1980 (see parent record 'The ecology and trophic role of caridean shrimps in the eelgrass community of Western Port, Victoria', File identifier: 268431c0-f18e-11dc-aaae-00188b4c0af8). An evaluation was made of summer and winter diets of Macrobrachium.intermedium, Pontophilus intermedius and Hippolyte caradina. Chlorotocella leptorhyncus was not present in the summer samples, so only the winter diet of this species was determined. Food items in the stomach were identified and the size of intact specimens was measured. All items were counted and assigned to a taxonomic category at the lowest possible level. The relative volume of individual prey items and taxonomic groups was also estimated.

During summer, M.intermediaum fed on a mix of animals (small crustaceans, gastropods, and polychaetes) and plant matter, and during winter, the diet was mostly plant matter. Polychaetes were the abundant prey items in the stomachs of P.intermedius, representing close to 70% of the diet in summer and winter. Almost 70% of the overall volume of food consumed by H.caradina was plant matter with small crustaceans, gastropods and insects making up the remaining proportion of the food consumed. The amount of plant matter in the diet increased in the winter months. C.leptorhyncus was found to ingest approximately equal volumes of animal and planter material with polychaetes the most abundant animal prey. The plant matter found in all samples was mostly dead eelgrass tissue.

本研究对1977年7月至1980年1月期间，于西港湾（Western Port Bay）通过底拖网采样获取的虾类胃容物展开分析（详见父级记录《维多利亚州西港湾鳗草群落中长臂虾类的生态学与营养功能》，文件标识符：268431c0-f18e-11dc-aaae-00188b4c0af8）。本次研究评估了中间沼虾（Macrobrachium intermedium）、中间单肢虾（Pontophilus intermedius）与卡罗琳藻虾（Hippolyte caradina）的夏、冬季食性。细吻绿管虾（Chlorotocella leptorhyncus）未在夏季采样中被检出，因此仅明确了该物种的冬季食性。研究人员对胃容物中的食物类群进行了分类鉴定，测量了完整标本的尺寸，对所有食物项进行计数并归类至尽可能低的分类阶元，同时估算了单个猎物及各分类类群的相对体积。

夏季时段，中间沼虾的食物由动物类群（小型甲壳类、腹足类及多毛类）与植物碎屑混合构成；冬季其食性则以植物类群为主。中间单肢虾的胃容物中，多毛类为优势猎物，在夏、冬季均占其总摄食量的近70%。卡罗琳藻虾的总摄食物质中，近70%为植物类群，剩余部分由小型甲壳类、腹足类及昆虫构成，且其食性中的植物占比在冬季有所上升。细吻绿管虾的摄食物质中，动物与植物类群的体积占比大致相当，其中多毛类为最优势的动物猎物。所有采样样本中的植物类群均以死亡的鳗草组织为主。