New Zealand Journal of Marine and Freshwater Research abstracts
Trap-based indicators of egg production following increases in minimum
legal size in Homarus americanus fisheries
M. John Tremblay
Fisheries and Oceans Canada
Bedford Institute of Oceanography
P.O. Box 1006
Dartmouth
NS B2Y4A2, Canada
email: TremblayJ@mar.dfo-mpo.gc.ca
Marc Lanteigne
Fisheries and Oceans Canada
Gulf Fisheries Centre
343 University Avenue
Moncton
NB E1C9B6, Canada
email: LanteigneM@dfo-mpo.gc.ca
Abstract Minimum legal size (MLS) is an important conservation
measure in trap fisheries for Homarus americanus. MLS has increased
in several management areas in the Canadian Maritimes since 1987. A key conservation
objective has been to increase egg production, with predictions of the effects
of MLS increase based on egg-per-recruit models. We evaluated whether expectations
of increases in ovigerous females (OF) were realised when MLS was increased.
Data were examined from at-sea samples of the commercial trap catch from
11 ports from 1986 to 2003. OF indicators were developed based on the OF
catch-per-unit-effort (CPUE) of different sizes, and on the percentage (PCT)
of females that were ovigerous. Because there were within-season increases
in CPUE and PCT, annual indicators were based on regressions of CPUE on day
in the season. There was considerable variability in all the time series
of OF annual indicators and any effects of smaller MLS increases could not
be detected. Increases in OF indicators were evident in areas that undertook
the largest MLS increases (6-6.5 mm CL).
Keywords lobster; Homarus americanus; minimum
legal size; E/R; egg production; indicators
M04042; Online publication date 8 June 2005 Received 10 February 2004;
accepted 12 July 2004
New Zealand Journal of Marine and Freshwater Research, 2005, Vol. 39:
775-783
0028-8330/05/3903-0775 © The Royal Society of New Zealand 2005
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