Seasonal cycles in weight and condition in Atlantic cod (Gadus morhua L.) in relation to fisheries

Mello, L. G. S.; Rose, George A.

doi:10.1016/j.icesjms.2005.03.008

Cited by 57 publications

(36 citation statements)

References 24 publications

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“…Often, condition indices reflect geographical and temporal variations in environmental conditions, prey availability and composition, spawning and feeding behaviour or genetic factors (Rätz and Lloret, 2003;Hidalgo et al, 2008). Thus in cod from Greenland waters, HSI has shown a wider range of values (Lloret and Rätz, 2000) compared with Northwest Atlantic cod (Dutil et al, 2003b), in which values were lower than those observed in cod from Newfoundland and Iceland (Marteinsdottir and Begg, 2002;Mello and Rose, 2005). Similar variations have been observed in K in cod (Krohn et al, 1997;Dutil, 1997b, 2000;Dutil et al, 2003b;Mello and Rose, 2005).…”

Section: Discussionmentioning

confidence: 80%

Changes of proximate composition, energy storage and condition of European hake (Merluccius merluccius, L. 1758) through the spawning season

2010

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a b s t r a c tEuropean hake is one of the most important economic resources for South European fleets; however, not many studies on its reproductive biology have been carried out. Gonadosomatic and hepatosomatic indices and condition factor were estimated. Proximate composition was analyzed in gonad, liver and muscle as indicators of female condition status; these results were converted to energy values. Variations of these parameters during the spawning season and through the year were studied. The hake population in Galician waters has a protracted spawning season with peak spawning from February to March. The proximate composition of tissues changes considerably throughout the spawning season although population spawning asynchrony masks temporal patterns. This work corroborates that energy dynamics associated with egg production in European hake are different from those observed in species from temperate waters (5 • -10 • C), depending more on environmental conditions and food availability during the spawning season than on body energy reserves.

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Section: Discussionmentioning

confidence: 80%

Changes of proximate composition, energy storage and condition of European hake (Merluccius merluccius, L. 1758) through the spawning season

2010

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“…Cod exhibited strong seasonality in weight and condition, reaching highest levels in late fall and lowest in spring during spawning (Mello and Rose 2005b). Simulations based on data collected during this research indicated that fishing during spawning required mortality to be 8-17% higher to catch the same quota by weight as a fall fishery.…”

Section: Lesson 8: Differential Fishing Mortality May Harm Spawning Cmentioning

confidence: 81%

“…Simulations based on data collected during this research indicated that fishing during spawning required mortality to be 8-17% higher to catch the same quota by weight as a fall fishery. Moreover, spring and summer fisheries resulted in lower yield (6%) and quality (5-26%) of fish products (Mello and Rose 2005b).…”

Section: Lesson 8: Differential Fishing Mortality May Harm Spawning Cmentioning

confidence: 99%

Rebuilding Atlantic Cod: Lessons from a Spawning Ground in Coastal Newfoundland

Rose¹,

Bradbury²,

deYoung³

et al. 2008

Resiliency of Gadid Stocks to Fishing and Climate Change

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Atlantic cod (Gadus morhua) was studied at the Bar Haven, Placentia Bay, Newfoundland (NAFO 3Ps stock unit) spawning ground from 1996 to 2003. Lessons applicable to management of rebuilding stocks derived from these studies are reviewed: (1) cod spawn in the same area each year, but numbers and timing vary (spawning biomass varied from 2,000 to 25,000 t, with timing protracted over at least 100 days); (2) courtship and spawning behavior is complex, and includes lekking, sound production, and vertical rituals; (3) large fish in good condition are necessary to large egg potential because fecundity increases exponentially with fish size-total egg potential varied considerably from year to year with spawning abundance, age changes, and mean liver condition in spawning females; (4) retention of early life stages did not explain local recruitment and rankings of annual densities of eggs, larvae and juveniles did not match with local recruitment during three years of study; (5) dispersal of early life stages, juveniles, and adults was density-dependent; (6) individual adults homed to the same spawnAuthorship assigned alphabetically after senior author. 198 Rose et al.-Rebuilding Atlantic Cod ing ground in sequential years, but others strayed; (7) egg potential was correlated with the return of adults to the spawning ground 4-5 years later (r 2 = 0.33, d.f. 3), and with recruitment to the full stock area (NAFO subdivision 3Ps) (r 2 = 0.96, d.f. 5), with only weak compensation in survival at low stock size; (8) fishing on spawning aggregations may harm reproductive potential; and (9) seasonal fisheries influence fishing mortality, commercial yield, and value. Management implications are discussed.

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“…We used Lambert's (2011Lambert's ( , 2012 equation that relates K calculated from total mass in January to K calculated from somatic mass in the following May in the northern Gulf of St. Lawrence to estimate a condition factor for the spring period (K s ), the most critical time of the year. The condition of Atlantic cod in Newfoundland remains virtually constant during the fall and into January (Mello & Rose 2005), thus allowing the use of fall condition as independent variable in Lambert's (2011Lambert's ( , 2012 …”

Section: Somatic Conditionmentioning

confidence: 99%

The role of harp seals, fisheries and food availability in driving the dynamics of northern cod

Buren¹,

Koen‐Alonso²,

Stenson³

2014

Mar. Ecol. Prog. Ser.

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The Atlantic cod Gadus morhua population off Newfoundland collapsed in the early 1990s due to over-exploitation, and despite marked reduction in fishing effort the stock remains depressed. Harp seal Pagophilus groenlandicus predation has been repeatedly proposed as an explanation for this lack of recovery, but other hypotheses include reduced prey availability and/or food quality (i.e. lack of capelin Mallotus villosus), as well as fisheries catches and environmental effects. Using a bioenergetics−allometric model, we gauged the relative contributions of these drivers on the lack of recovery and dynamics of the northern cod stock. Biomass dynamics were best explained by a combination of fisheries removals and capelin availability, whereas seal consumption was found not to be an important driver of the northern cod stock. Prey availability was linked to reduced somatic condition during the 1990s and 2000s. We discuss evidence that suggests that cod may be experiencing depensatory dynamics, but not related to a 'predator pit effect'. Our study suggests that trophic control is bottom-up, and that a depressed capelin stock could be a serious impediment for cod rebuilding.

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Seasonal cycles in weight and condition in Atlantic cod (Gadus morhua L.) in relation to fisheries

Cited by 57 publications

References 24 publications

Changes of proximate composition, energy storage and condition of European hake (Merluccius merluccius, L. 1758) through the spawning season

Changes of proximate composition, energy storage and condition of European hake (Merluccius merluccius, L. 1758) through the spawning season

Rebuilding Atlantic Cod: Lessons from a Spawning Ground in Coastal Newfoundland

The role of harp seals, fisheries and food availability in driving the dynamics of northern cod

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