Influence of Hydrologic Conditions of the Lower Ob Floodplain on Reproduction in Coregonids

The influence of the water level in the period of the open river channel and the duration of lower floodplain inundation on the feeding conditions, abundance, and population state of coregonids in the Lower Ob was investigated. The long-term dynamics of catches of some coregonid species was analyzed and compared with changes in the hydrologic conditions in the floodplain. The relationship between basic hydrologic conditions in the Lower Ob (water level in the period of the open channel, the duration of the lower floodplain inundation), the coregonid population sizes, the state of spawners, and the size of catches is demonstrated.     

ABNORMALITIES AND DISEASES OBSERVED IN COMMERCIAL FISH CATCHES FROM BISCAYNE BAY,FLORIDA1

ABSTRACT: Many of the most productive fishing grounds in the United States are estuaries and bays which are located near population and industrial centers, and therefore subjected to pollution. Observations made on 17 fish species from commercial catches harvested in north Biscayne Bay, Florida, an urban area, showed high numbers of individuals suffering from abnormalities and diseases. Seven groups of disorders most frequently affected bottom feeders. Fin and integumental hemorrhages occurred in all individuals in 26 of 43 catches of Mugil cephalus (striped mullet), and in all individuals in 24 of 30 catches of Micropogon undulatus (Atlantic croaker). Disorders occurring consistently in a location exposed to pollutants, but uncommon in other areas of the species' range, point to environmental stress as a probable cause.