Relative effects of trap versus trawl fisheries on population dynamics of the northern cod (Gadus morhua) stock
We compared the effects of the inshore trap and the offshore trawl fisheries on the population dynamics of the northern cod (Gadus morhua) stock using data analyses and simulation modelling. We first statistically characterized the catch versus stock biomass relationships for the two fisheries (1977...
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ftcarletonunivir:oai:carleton.ca:1431 2023-05-15T16:19:00+02:00 Relative effects of trap versus trawl fisheries on population dynamics of the northern cod (Gadus morhua) stock Fahrig, L. (Lenore) Pope, S.E. Henein, K.M. Rose, G.A. 1998-05-27 https://ir.library.carleton.ca/pub/1431 en eng https://ir.library.carleton.ca/pub/1431 Canadian Journal of Fisheries and Aquatic Sciences vol. 55 no. 1, pp. 76-85 info:eu-repo/semantics/article 1998 ftcarletonunivir 2022-02-06T21:50:17Z We compared the effects of the inshore trap and the offshore trawl fisheries on the population dynamics of the northern cod (Gadus morhua) stock using data analyses and simulation modelling. We first statistically characterized the catch versus stock biomass relationships for the two fisheries (1977-1986). We found a significant (P < 0.0001) relationship between the trawl catch at time t and the stock biomass at time t - 2. No temporal lag was evident in the trap catch versus stock biomass relationship. The variability in these two relationships was similar. We then modelled the catch and stock biomass dynamics of the two fisheries in parallel, incorporating the observed catch versus stock biomass relationships, but assuming equal mean catches, to examine the effects on cod population dynamics of the temporal lag and variability in the catch versus stock biomass relationships. The results suggest that, for the same amount of fish taken, a quota-based trawl fishery presents a much greater risk of collapse to the cod stock than does an inshore trap fishery. Current management methods overestimate the 'safe' catch for the trawl fishery because they do not incorporate the consequences of the lag in the relationship between stock biomass and trawl catch. Article in Journal/Newspaper Gadus morhua Carleton University's Institutional Repository |
institution |
Open Polar |
collection |
Carleton University's Institutional Repository |
op_collection_id |
ftcarletonunivir |
language |
English |
description |
We compared the effects of the inshore trap and the offshore trawl fisheries on the population dynamics of the northern cod (Gadus morhua) stock using data analyses and simulation modelling. We first statistically characterized the catch versus stock biomass relationships for the two fisheries (1977-1986). We found a significant (P < 0.0001) relationship between the trawl catch at time t and the stock biomass at time t - 2. No temporal lag was evident in the trap catch versus stock biomass relationship. The variability in these two relationships was similar. We then modelled the catch and stock biomass dynamics of the two fisheries in parallel, incorporating the observed catch versus stock biomass relationships, but assuming equal mean catches, to examine the effects on cod population dynamics of the temporal lag and variability in the catch versus stock biomass relationships. The results suggest that, for the same amount of fish taken, a quota-based trawl fishery presents a much greater risk of collapse to the cod stock than does an inshore trap fishery. Current management methods overestimate the 'safe' catch for the trawl fishery because they do not incorporate the consequences of the lag in the relationship between stock biomass and trawl catch. |
format |
Article in Journal/Newspaper |
author |
Fahrig, L. (Lenore) Pope, S.E. Henein, K.M. Rose, G.A. |
spellingShingle |
Fahrig, L. (Lenore) Pope, S.E. Henein, K.M. Rose, G.A. Relative effects of trap versus trawl fisheries on population dynamics of the northern cod (Gadus morhua) stock |
author_facet |
Fahrig, L. (Lenore) Pope, S.E. Henein, K.M. Rose, G.A. |
author_sort |
Fahrig, L. (Lenore) |
title |
Relative effects of trap versus trawl fisheries on population dynamics of the northern cod (Gadus morhua) stock |
title_short |
Relative effects of trap versus trawl fisheries on population dynamics of the northern cod (Gadus morhua) stock |
title_full |
Relative effects of trap versus trawl fisheries on population dynamics of the northern cod (Gadus morhua) stock |
title_fullStr |
Relative effects of trap versus trawl fisheries on population dynamics of the northern cod (Gadus morhua) stock |
title_full_unstemmed |
Relative effects of trap versus trawl fisheries on population dynamics of the northern cod (Gadus morhua) stock |
title_sort |
relative effects of trap versus trawl fisheries on population dynamics of the northern cod (gadus morhua) stock |
publishDate |
1998 |
url |
https://ir.library.carleton.ca/pub/1431 |
genre |
Gadus morhua |
genre_facet |
Gadus morhua |
op_source |
Canadian Journal of Fisheries and Aquatic Sciences vol. 55 no. 1, pp. 76-85 |
op_relation |
https://ir.library.carleton.ca/pub/1431 |
_version_ |
1766005309961142272 |