Journal
ICES JOURNAL OF MARINE SCIENCE
Volume 76, Issue 7, Pages 2179-2192Publisher
OXFORD UNIV PRESS
DOI: 10.1093/icesjms/fsz107
Keywords
age-length-structured population model; demographic consequences; Rosa Lee phenomenon; selectivity changes; stock effects
Categories
Funding
- European Maritime and Fisheries Fund (EMFF) of the European Union (EU) under the Data Collection Framework (DCF) [2017/1004]
Ask authors/readers for more resources
When size-selective fishing removes faster-growing individuals at higher rates than slower-growing fish, the surviving populations will become dominated by slower-growing individuals. When this Rosa Lee phenomenon is ignored, bias may occur in catch and stock projections. In a length-and-age-based model we quantified the effects through simulations of a simplified fishery on a stock that resembles Western Baltic cod. We compared outcomes of runs with and without taking account of the Rosa Lee phenomenon in scenarios of changes in fishing mortality. We found that, when only fishing rate was changed, the biases in predictions of spawning-stock biomass (SSB), yield and catches of undersized fish were relatively small (<10% in absolute values). When the selectivity parameters of the gear were increased, the bias in the prediction of the catches of undersized fish was very substantial (+120 to 160%). When the selectivity parameters were decreased, the biases in the predictions of SSB, yield and catches of undersized fish, were substantial (25-50% in absolute values). With slower mean growth the biases became more pronounced. We conclude that in short-term forecasts, medium-term projections, and MSE simulations featuring selectivity changes, the Rosa Lee phenomenon should be accounted for, ideally by using length-based models.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available