Did reduced recruitment contribute to the collapse of Atlantic cod?
There survey results from six stocks of Atlantic cod do not support the hypothesis that the cod collapse off eastern Canada resulted from poor recruitment (Table. 1). Survey results of different cod stock in various regions, as depicted in Table 1, showed that the recruitment from the previous year classes that would have comprised most of the spawners during the year of the collapse was not significantly different from previous year classes recruitment. Further, of the six stocks, reduced recruitment was seen in mid-1980s in southern Grand Bank, northern Gulf of St. Lawrence, and Eastern Scotian Shelf. This may be due to the fact that spawners biomass was at a historical …show more content…
A study completed by Planque and Fredou (1997) showed that their exists a correlation between recruitment of fish and changes in the environment (Fig. 3). Stocks located in warm water showed a negative recruitment relationship. Therefore, warming of the water from climate change preceding the collapse of the cod stock and its negative effects on recruitment and spawning biomass may have exasperated other problems such as overfishing. This issue is highlighted in a recent study conducted by Pershing and colleagues (2015) where they found that warmer waters reduce the productivity of spawning females. Suggesting that the warming of the water during the early 1990s contributed to a lower spawning biomass and recruitment levels, as seen in Fig. 2, and fishing management models failed to account for this change, leading to higher catch quotas that could not have been sustained (Pershing et al. 2015). Therefore, there is strong data suggesting lower recruitment and biomass level exasperated the overfishing problem of the Atlantic cod stock; however, there is exists no strong evidence to suggest that the reduced recruitment was one of the major reasons for collapse (Pershing et. al, 2015; Myers et al.
There survey results from six stocks of Atlantic cod do not support the hypothesis that the cod collapse off eastern Canada resulted from poor recruitment (Table. 1). Survey results of different cod stock in various regions, as depicted in Table 1, showed that the recruitment from the previous year classes that would have comprised most of the spawners during the year of the collapse was not significantly different from previous year classes recruitment. Further, of the six stocks, reduced recruitment was seen in mid-1980s in southern Grand Bank, northern Gulf of St. Lawrence, and Eastern Scotian Shelf. This may be due to the fact that spawners biomass was at a historical …show more content…
A study completed by Planque and Fredou (1997) showed that their exists a correlation between recruitment of fish and changes in the environment (Fig. 3). Stocks located in warm water showed a negative recruitment relationship. Therefore, warming of the water from climate change preceding the collapse of the cod stock and its negative effects on recruitment and spawning biomass may have exasperated other problems such as overfishing. This issue is highlighted in a recent study conducted by Pershing and colleagues (2015) where they found that warmer waters reduce the productivity of spawning females. Suggesting that the warming of the water during the early 1990s contributed to a lower spawning biomass and recruitment levels, as seen in Fig. 2, and fishing management models failed to account for this change, leading to higher catch quotas that could not have been sustained (Pershing et al. 2015). Therefore, there is strong data suggesting lower recruitment and biomass level exasperated the overfishing problem of the Atlantic cod stock; however, there is exists no strong evidence to suggest that the reduced recruitment was one of the major reasons for collapse (Pershing et. al, 2015; Myers et al.