XXXX substances and reproductive disorders in Baltic fish and crustaceans.

@entity137 @entity132 @entity318 @entity26 @entity9138 @entity600 @entity3215 @entity74 @entity204 @entity42549
In the Baltic Sea ecosystem reproductive disorders have occurred in top consumers such as seals and some fish-eating birds, due to biomagnification of toxic substances, e.g. @entity318 and @entity3215 . @entity132 have also affected fish during the last 25 years. However, there is no strong evidence that toxic substances have caused these problems. Rather, the disorders seem to result from a combination of two or more biotic or abiotic factors. The M74 syndrome, which kills fry of salmon and @entity42549 , is characterized by a deficiency of @entity9138 ( @entity9138 ). Several factors may contribute to the @entity9138 deficiency, including the diet of salmon in the sea and halogenated organic compounds. Cod do not develop M74, and poor cod recruitment is mainly due to poor @entity26 conditions in the spawning areas in combination with overfishing. @entity137 compounds in pulp-mill effluents retard gonadal development in perch, but the mechanisms and the active substances have not been identified. Recruitment problems in perch in the coastal waters outside some pulp mills may also be explained by a lack of food items for juvenile fish, rather than reproductive failure. There are very limited data on reproductive disorders in crustaceans from the Baltic Sea. Most data come from studies of the benthic amphipod Monoporeia affinis, which has been used in monitoring programs. Several signs of @entity74 have been reported in this amphipod, e.g. @entity600 and @entity204 of embryos, and asynchronous maturation of males and females.
