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Title: DELAWARE FISH HEALTH MONITORING: GROSS AND HISTOLOGICAL OBSERVATIONS IN ATLANTIC MENHADEN (BREVOORTIA TYRANNUS) AND BAY ANCHOVY (ANCHOA MITCHELLI) IN 1999

Author
item Evans, Joyce
item HUMPHRIES, E - DELAWARE DEPARTMENT OF NA
item DICKEY, E - DELAWARE DEPARTMENT OF NA
item Klesius, Phillip

Submitted to: Meeting Abstract
Publication Type: Other
Publication Acceptance Date: 9/20/2000
Publication Date: 10/18/2000
Citation: EVANS, J.J., HUMPHRIES, E., DICKEY, E., KLESIUS, P.H. DELAWARE FISH HEALTH MONITORING: GROSS AND HISTOLOGICAL OBSERVATIONS IN ATLANTIC MENHADEN (BREVOORTIA TYRANNUS) AND BAY ANCHOVY (ANCHOA MITCHELLI) IN 1999. CDC NATIONAL CONFERENCE ON PFIESTERIA: FROM BIOLOGY TO PUBLIC HEALTH. POSTER. 2000.

Interpretive Summary:

Technical Abstract: Study Objectives: In 1999, the Ecological Assessment Branch began monitoring fish health as part of a multi-faceted Pfiesteria Surveillance Monitoring Program. The objectives of the monitoring are to determine whether fish health is a possible indicator of toxic Pfiesteria activity or is correlated to Pfiesteria- like organisms (PLO's), phytoplankton, or water quality. Methods: Fish collections were conducted at sites where PLO's have been documented in Delaware inland bays from June to October. Fish health was evaluated through grossly visible lesions and /or parasites and histopathology. Results: None of the fifteen fish species examined (n=914) had ulcerative lesions. Atlantic menhaden (Brevoortia tyrannus) (n=342) and bay anchovy (Anchoa mitchelli) (n=241) had copepod crustaceans identified as adult females of the Family Pennellidae: genus Lernaeenicus (presumptively radiatus). Highest incidences of Lernaeenicus sp. occurred on Atlantic menhaden (12.6%). Dorso-lateral aspects of the left side of the fish were preferred parasite attachment sites. Histologically, diffuse and severe inflammation and muscle liquefaction were seen as a consequence of Lernaeenicus sp. Of note, was the appearance of myxosporidians (Kudoa sp.) both encysted and unencysted in the musculature of normal appearing Atlantic menhaden. In contrast, menhaden with grossly visible parasites did not have myxosporidians in their musculature. No fungal entities were seen in any of the menhaden. Correlations between water quality, phytoplankton and gross and histological observations have not been completed. Parasitic and lesion incidence monitoring are ongoing in 2000.