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Stock‐Recruitment Relationships of Alewives and Blueback Herring Returning to the Mactaquac Dam, Saint John River, New Brunswick
Author(s) -
Jessop B. M.
Publication year - 1990
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(1990)010<0019:srroaa>2.3.co;2
Subject(s) - alewife , fishery , alosa , herring , stock (firearms) , biology , fish migration , geography , fish <actinopterygii> , archaeology
Linear empirical stock‐recruitment relationships were found between the escapement of alewives Alosa pseudoharengus and blueback herring A. aestivalis to the Mactaquac Dam headpond on the Saint John River, New Brunswick, in year i and the total returns to the fishway at the dam 5 years later. The proportion of fish that had spawned in previous years in the total return varied in response to stock management. Variable numbers of immigrant fish, in conjunction with spawners from previous years, caused total returns to result in overestimation of the true stock–recruitment relationship. For both species, the spawning stock in year i was significantly related to year‐class abundance at age 3. Increasing escapements of blueback herring slightly reduced alewife year‐class size, but the size of alewife escapements had no effect on year‐class size for blueback herring. Increasing discharge (May–June) from the dam reduced the year‐class abundance of blueback herring but not that of alewives.