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Differential Growth and Survival of Weekly Age‐0 Black Crappie Cohorts in a Florida Lake
Author(s) -
Pine William E.,
Allen Micheal S.
Publication year - 2001
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(2001)130<0080:dgasow>2.0.co;2
Subject(s) - biology , bosmina , hatching , juvenile , predation , zoology , juvenile fish , daphnia , centrarchidae , ecology , fishery , fish <actinopterygii> , zooplankton , micropterus
Black crappies Pomoxis nigromaculatus exhibit highly variable survival to adulthood because of their varying larval and juvenile abundance, growth, and mortality during early life. We examined how growth and mortality changed with hatch date, prey density, and water temperature for 7‐d cohorts of juvenile black crappies in Lake Wauberg, Florida (a 150‐ha hypereutrophic natural lake) during spring and summer 1998. Fish were collected once per week from March through June and twice per month during July and August by means of an otter trawl. Based on daily otolith rings, hatching occurred over a 12‐week period (1 March−18 May). The mean daily growth rate (DGR) was positively related to water temperature, which increased over the hatching season. Common prey taxa included calanoid copepods, Daphnia and Bosmina spp., and cyclopoid copepods. The total density of these taxa did not differ significantly among collection dates. Mean hatching date shifted from mid‐March for fish collected in mid‐April to early April for fish collected in late May. Early‐hatched fish had lower DGRs (0.72 mm/d, compared with 0.76 mm/d for fish hatched in midseason and 0.82 mm/d for those hatched late in the season), higher mean daily instantaneous mortality rates (0.25, compared with 0.09 for the other two groups), and lower survival to the end of the first summer. As a result, the 1998 year‐class of black crappies in Lake Wauberg was probably dominated by middle‐ and late‐hatched individuals by the end of the first summer.