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Canadian Stock Assessment Secretariat
Research Document - 2000/166
Stock assessment of rock sole and English sole in
Hecate Strait for 2000/2001
By J. Fargo, A.R. Kronlund, J.T. Schnute, and R. Haigh
Abstract
The authors summarize biological information and analyse
catch-age data for stocks of rock sole and English sole in Hecate
Strait. Their analysis uses a state space catch-age model to reconstruct
stock histories. Results indicate that recruitment and biomass of both
species have declined over the last four years. In particular,
recruitments in 1998 and 1999 reached a historic lows for both species.
The authors compare biomass estimates from the catch-age analysis with
those obtained using swept-area expansions of commercial and research
survey catch rates. All analyses show similar stock trends, although
estimates have high variability. They use equilibrium calculations to
determine various fishing mortality reference points. These suggest
lower, more conservative, fishing mortality levels than those found in
previous analyses. The authors estimate yield by applying a target
fishing mortality to the 1999 estimates of biomass from the catch-age
analysis. Current yield recommendations are reduced significantly from
previous years. The yield range for rock sole is 600-700 t, while
the yield range for English sole is 300-400 t. The authors
synthesize this information to provide advice to managers on harvest
levels for the 2001/2002 fishing year.
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83 pages (1365K)
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