Shrimp fauna of the Toyo-gawa River, Aichi Prefecture, Japan

Abstract

There are few reports of shrimp in the Toyo-gawa River in Higashi-Mikawa district, Aichi prefecture; therefore, basic data need to be collected to implement environmental protection activities. Shrimp fauna was collected with a hand net and surveyed from 13 sites in the lower and middle reaches of the Toyo-gawa River between 2010 and 2013. Sixteen shrimp species from seven families were identified. The largest shrimp population identified was Acetes japonicus, and the species with the widest distribution was Macrobrachium nipponense. Among the identified species, the only alien species was Procambarus clarkii. A cluster analysis divided the data into three groups: seawater species occurred in the lower part of the brackish water area, amphidromous species in the upper part of the brackish water area and lower part of the fresh water area, and freshwater species in the central to upper part of the freshwater area. Therefore, shrimp distribution is considered to be greatly affected by salinity.