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Predation on Recently Released Larval American Shad in the Susquehanna River Basin
Author(s) -
Johnson James H.,
Dropkin David S.
Publication year - 1992
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1992)012<0504:porrla>2.3.co;2
Subject(s) - alosa , stocking , predation , micropterus , fishery , biology , notropis , larva , dorosoma , ichthyoplankton , forage fish , bass (fish) , ecology , fish <actinopterygii> , fish migration
The release of 18‐d‐old larvae of American shad Alosa sapidissima is a major component of a program to restore shad in the Susquehanna River. At stocking sites we documented predation by the resident fish community on recently released American shad. Fish collections were made on three occasions 30–60 min after release of 0.38, 0.67, and 1.5 million larval American shad. All 15 species captured at the stocking sites had consumed larval shad. American shad larvae were in the stomachs of nearly 90% of the 1,163 examined fish and represented over 90% of stomach contents by weight. The predation rate was greatest for juvenile smallmouth bass Micropterus dolomieu (mean, 345 larvae/fish from 15 specimens) at the site of the highest‐level shad stocking. The release of larval shad apparently triggered a feeding response in some cyprinids, and consumption of larvae increased with the number of shad released for numerically dominant spotfin shiners Cyprinella spiloptera and mimic shiners Notropis volucellus . Our results suggest that predation may be a key factor governing the survival of recently released American shad larvae near stocking sites in the Susquehanna River. Further research leading to a better understanding of predation on larval American shad is warranted in order to identify alternative stocking procedures that may reduce predation.