Common carp in the Upper Mississippi River

Since its escapement into the Upper Mississippi River (UMR) and rapid expansion in the late 1900's, the common carp, Cyprinus carpio, has become a major component of the river fishery. Mean annual harvest value for this species was $270000 between 1953 and 1977. Recent evidence suggests that common carp may not be as abundant in the river as they have been in the past. We summarized historical commerical information on common carp in the UMR to put its current harvest levels in perspective. A major factor responsible for recent low annual harvests has been PCB contamination of the river in the Lake Pepin area. Market and biological factors probably have also contributed to declining harvests. To help explain why common carp populations in the UMR may be declining, we reviewed literature pertaining to the ecology of the species, particularly that from the river, its tributaries, or midwestern lakes. We included information on how common carp are controlled by environmental factors, and how they interact with other biota. Most aspects of carp ecology in the UMR and other areas are similar. Exceptions relate primarily to their response to annual water level regimes of the river. We postulate that population declines and absent year classes in the UMR may be related to poor recruitment during high- or variable-water years.     

Intermediate filament typing of tumor cells in fine needle aspirates by means of monoclonal antibodies

Well-characterized monoclonal antibodies directed against different intermediate filament proteins were used in the typing of tumor cells in 30 fine needle aspiration (FNA) biopsy specimens received for routine cytologic examination to assess the value of intermediate filament typing in FNA cytology. Tumors from sites that included liver, large bowel, pancreas, breast, skin, thyroid, thigh and kidney were examined with monoclonal antibodies specific for either all keratins or keratin subsets, vimentin, desmin or specific neurofilament polypeptides. Intermediate filament typing helped to confirm, revise or refine the diagnoses made by light microscopy and provided information of value in the classification of tumors of uncertain origin.     

Fine-scale population structure in Atlantic salmon from Maine's Penobscot River drainage

We report a survey of microsatellite DNAvariation in Atlantic salmon from theunimpounded lower reaches of Maine's PenobscotRiver. Our analysis indicates that Atlanticsalmon in the Penobscot River are distinct fromother populations that have little or nohistory of human-mediated repopulation,including two of its tributaries, Cove Brookand Kenduskeag Stream, another Maine river, theDucktrap, and Canada's Miramichi and Ganderrivers. Significant heterogeneity was detectedin allele frequency among all threesubpopulations sampled in the Penobscotdrainage. The high resolution of the 12-locussuite was quantified using maximum likelihoodassignment tests, which correctly identifiedthe source of 90.4–96.1% of individuals fromwithin the Penobscot drainage. Currentpopulations are clearly isolated from eachother, however we are unable to determine fromthe present data whether the populations inCove Brook and Kenduskeag Stream are recentlydiverged from populations stocked into thePenobscot River over the last century, or areaboriginal in origin. The degree of populationstructure identified in the Penobscot drainageis noteworthy in light of its lengthy historyof systematic restocking, the geographicproximity of the subpopulations, and the extentof the differentiation. Similar populationstructure on this extremely limited geographicscale could exist among Atlantic salmon runselsewhere in Maine and throughout the species'range and should be taken into account forfuture management decisions.