Migration of wild and cultivated juvenile honmoroko Gnathopogon caerulescens of from the spawning and nursery areas in Lake Biwa were investigated, both in the Ibanaiko Lagoon and its outlet to Daido River, using beam‐trawl surveys in 2013 and 2014. The study demonstrated migration of G. caerulescens from a nursery lagoon toward Lake Biwa after the juvenile stage. These findings appear to be the first direct evidence for migra...

This work examined three different phenotypes of the yellow‐eel stage of the European eel Anguilla anguilla , broad‐heads, narrow‐heads and eels with an intermediate head shape. The aim was to see whether broad‐headed A. anguilla , which generally consume harder, larger prey, such as crustaceans and fish, exerted greater bite force than the narrow‐headed variant, which mainly consume soft, small prey such as chironomid larvae....

Cytochrome p450 1A (cyp1A), pigmented macrophage aggregate (PMA) variables and fish descriptive characteristics were measured in field‐caught adult carp Cyprinus carpio from two upstream reference sites and two downstream Superfund sites contaminated with polychlorinated biphenyls (PCBs) in the Kalamazoo River, MI, U.S.A. Liver PCB content in fish differed among sites, and immunocytochemical cyp1A protein expression was signif...

We present a model of a male–female evolutionary game on mate‐locating behaviour. Two major mating systems are considered: “lek polygyny” (in which males aggregate to wait for females searching for males) and “searching polygyny” (in which males search for females emerging or waiting for males). The model predicts that lek polygyny is favoured (i) when male survivorship during lekking is sufficiently higher than that during ma...