Condition and size composition effects on the simulated relationship between spawner biomass and total egg production for Northeast Arctic cod (Gadus morhua L.)
Spawner biomass (SB) is often assumed to be proportional to total egg production (TEP) by fish stocks. Recent studies suggest that this assumption may not be valid, particularly when the physiological condition of fish varies. This study used Monte Carlo techniques to simulate the relationship betwe...
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ftimr:oai:imr.brage.unit.no:11250/105923 2023-05-15T14:30:25+02:00 Condition and size composition effects on the simulated relationship between spawner biomass and total egg production for Northeast Arctic cod (Gadus morhua L.) Kvalsund, Merete Marshall, C. Tara 1999 application/pdf http://hdl.handle.net/11250/105923 eng eng ICES ICES CM Documents;1999/Y:6 This report is not to be cited without prior reference to the authors http://hdl.handle.net/11250/105923 10 s. cod torsk biomass biomasse egg production eggproduksjon VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923 Working paper 1999 ftimr 2021-09-23T20:15:50Z Spawner biomass (SB) is often assumed to be proportional to total egg production (TEP) by fish stocks. Recent studies suggest that this assumption may not be valid, particularly when the physiological condition of fish varies. This study used Monte Carlo techniques to simulate the relationship between SB and TEP for Northcast Arctic cod (Gadus morhua). In the first simulation exercise, reproductive traits reflecting condition (length-specific maturity, weight and fecundity) were varied according to food abundance (capelin biomass) while the size composition (numbers at length) was held constant. In the second exercise, the size composition, as described by the modal length of spawners, was varied and condition was held constant. In the final exercise, condition and size composition were varied simultaneously. The first exercise indicated that variation in TEP was not constant but increased as the SB increased. The second exercise showed that, for a given SB, TEP increased with increasing modallength of spawners. Comparing the results of the first and second exercise showed that food-dependent variation in condition introduced greater variability into the relationship between SB and TEP than did shifting the size composition. When condition and size composition were varied simultaneously, as would be expected in wild stocks, TEP exhibited approximately 4-fold level of variation at any given SB. Report Arctic cod Arctic Gadus morhua Northeast Arctic cod Institute for Marine Research: Brage IMR Arctic |
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Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
topic |
cod torsk biomass biomasse egg production eggproduksjon VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923 |
spellingShingle |
cod torsk biomass biomasse egg production eggproduksjon VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923 Kvalsund, Merete Marshall, C. Tara Condition and size composition effects on the simulated relationship between spawner biomass and total egg production for Northeast Arctic cod (Gadus morhua L.) |
topic_facet |
cod torsk biomass biomasse egg production eggproduksjon VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923 |
description |
Spawner biomass (SB) is often assumed to be proportional to total egg production (TEP) by fish stocks. Recent studies suggest that this assumption may not be valid, particularly when the physiological condition of fish varies. This study used Monte Carlo techniques to simulate the relationship between SB and TEP for Northcast Arctic cod (Gadus morhua). In the first simulation exercise, reproductive traits reflecting condition (length-specific maturity, weight and fecundity) were varied according to food abundance (capelin biomass) while the size composition (numbers at length) was held constant. In the second exercise, the size composition, as described by the modal length of spawners, was varied and condition was held constant. In the final exercise, condition and size composition were varied simultaneously. The first exercise indicated that variation in TEP was not constant but increased as the SB increased. The second exercise showed that, for a given SB, TEP increased with increasing modallength of spawners. Comparing the results of the first and second exercise showed that food-dependent variation in condition introduced greater variability into the relationship between SB and TEP than did shifting the size composition. When condition and size composition were varied simultaneously, as would be expected in wild stocks, TEP exhibited approximately 4-fold level of variation at any given SB. |
format |
Report |
author |
Kvalsund, Merete Marshall, C. Tara |
author_facet |
Kvalsund, Merete Marshall, C. Tara |
author_sort |
Kvalsund, Merete |
title |
Condition and size composition effects on the simulated relationship between spawner biomass and total egg production for Northeast Arctic cod (Gadus morhua L.) |
title_short |
Condition and size composition effects on the simulated relationship between spawner biomass and total egg production for Northeast Arctic cod (Gadus morhua L.) |
title_full |
Condition and size composition effects on the simulated relationship between spawner biomass and total egg production for Northeast Arctic cod (Gadus morhua L.) |
title_fullStr |
Condition and size composition effects on the simulated relationship between spawner biomass and total egg production for Northeast Arctic cod (Gadus morhua L.) |
title_full_unstemmed |
Condition and size composition effects on the simulated relationship between spawner biomass and total egg production for Northeast Arctic cod (Gadus morhua L.) |
title_sort |
condition and size composition effects on the simulated relationship between spawner biomass and total egg production for northeast arctic cod (gadus morhua l.) |
publisher |
ICES |
publishDate |
1999 |
url |
http://hdl.handle.net/11250/105923 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic cod Arctic Gadus morhua Northeast Arctic cod |
genre_facet |
Arctic cod Arctic Gadus morhua Northeast Arctic cod |
op_source |
10 s. |
op_relation |
ICES CM Documents;1999/Y:6 This report is not to be cited without prior reference to the authors http://hdl.handle.net/11250/105923 |
_version_ |
1766304259489398784 |