Seasonal dynamics in feeding, organ weights, and reproductive maturation of Atlantic cod (Gadus morhua) in the southern Gulf of St Lawrence

Schwalme, Karl; Chouinard, Ghislain A.

doi:10.1006/jmsc.1999.0458

Cited by 107 publications

(124 citation statements)

References 30 publications

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“…To account for differences in fish size, a fullness index (FI; Schwalme & Chouinard 1999, Björnsson 2002 was calculated for each non-empty stomach as: (4) where W cap is the weight (g) of capelin in the stomach of an individual cod. For the annual analysis of FI, ages 5 and 6 yr were combined in order to increase the number of data points.…”

Section: Methodsmentioning

confidence: 99%

“…Eliassen & Vahl 1982b, Lambert & Dutil 1997a, Schwalme & Chouinard 1999, Mello & Rose 2005. Condition tends to peak between September and December following the feeding season, with minimum values associated with spawning reached in the spring.…”

Section: (Continued)mentioning

confidence: 99%

“…Fish condition is influenced by the combined effects of physiological and environmental factors (Cui & Wootton 1988) and follows seasonal and annual cycles in cod (Lambert & Dutil 1997a, Schwalme & Chouinard 1999, Lloret & Rätz 2000, reflecting patterns of energy accumulation and depletion during periods of intense feeding, maturation, reproduction, migration and over-wintering (Eliassen & Vahl 1982a,b, Holdway & Beamish 1984, Lambert & Dutil 1997a. Simple metrics of condition, such as the commonly utilised Fulton's K and hepatosomatic index (H), are based only on length and weight data, but have been found to be reliable indicators of biochemical composition and energy reserves (those stored in muscle proteins and liver lipids respectively) of Atlantic cod (Lambert & Dutil 1997b).…”

Section: Introductionmentioning

confidence: 99%

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Spatial and temporal trends in condition of Atlantic cod Gadus morhua on the Icelandic shelf

Pardoe¹,

Thórdarson²,

Marteinsdóttir³

2008

Mar. Ecol. Prog. Ser.

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Interannual (1993Interannual ( to 2006, spatial and bathymetric trends in the hepatosomatic index (H) and relative body condition index (Kr) of Atlantic cod Gadus morhua in Icelandic waters were investigated from data collected during annual spring (March) groundfish surveys. Individual stomach content data were analysed to assess the relationship between condition and consumption of capelin Mallotus villosus. Liver condition was found to vary with region and depth, tending to be highest in deeper water and in the northern and eastern regions; where temperatures were relatively cold and capelin consumption relatively high. A continuous decline in condition of cod in waters off the east coast was observed throughout the study period. Mature cod were found to be in significantly better condition than immature cod of the same age, and mature females were in better condition than mature males. Different patterns emerged from the 2 condition indices; little variation in Kr was observed whereas H was found to be a dynamic index of condition, suggesting that these metrics are not equivalent measures of cod bioenergetic condition.

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Section: Methodsmentioning

confidence: 99%

Section: (Continued)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spatial and temporal trends in condition of Atlantic cod Gadus morhua on the Icelandic shelf

Pardoe¹,

Thórdarson²,

Marteinsdóttir³

2008

Mar. Ecol. Prog. Ser.

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“…Nevertheless, fish exhibiting critically low condition for survival (according to the value determined to be critical in a laboratory setting) were found in the northern and southern Gulf of St. Lawrence Dutil 1997, Schwalme andChouinard 1999) during the early to mid-1990s. Dutil and Lambert (2000) concluded that natural mortality from poor condition contributed to lower production of the northern Gulf of St. Lawrence cod.…”

Section: Preymentioning

confidence: 99%

Decline and Recovery of Atlantic Cod (Gadus morhua) Stocks throughout the North Atlantic

Lilly¹,

Wieland²,

Rothschild³

et al. 2008

Resiliency of Gadid Stocks to Fishing and Climate Change

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Many stocks of Atlantic cod (Gadus morhua) on both sides of the North Atlantic are currently at much reduced levels of biomass, but this situation is not in all instances the result of long, continuous decline. Most Northwest Atlantic stocks declined to low levels during the 1970s, but increased during the 1980s before declining even more severely during the late 1980s and early 1990s. Several of these stocks have shown little recovery despite severe restrictions on directed fishing. Many stocks in the Northeast Atlantic have experienced sustained increases and sustained decreases, but generally not in concert. Among-stock comparisons illustrate that fishing has played a dominant role in the dynamics of all cod stocks, but variability in climate has contributed to variability in recruitment, individual growth, and natural mortality. A cooling event during the last three decades of the twentieth century contributed to the rapid decline of several stocks in the Northwest Atlantic, and changes in life-history traits (growth rate, age and size at maturity) and in the biotic environment (predators and prey) may be contributing to recovery being slow.

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“…Simple condition indices (CF) were calculated as a proxy for energy reserve of the cod (e.g., Schwalme andChouinard 1999, Storr-Paulsen et al 2006), according to:…”

Section: Condition Factormentioning

confidence: 99%

Occurrence of anisakid nematodes in Atlantic cod (Gadus morhua) and Greenland cod (Gadus ogac), West Greenland

Mouritsen

Hedeholm

Schack

et al. 2010

Acta Parasitologica

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Anisakid nematodes commonly infect gadids, and are of economic and aesthetic importance to the commercial fishing industry in Greenland as some species are pathogenic to humans. However, very little is known about the occurrence of these parasites and their impact on the hosts in Greenland waters. During a survey in 2005, stomach sample of 227 Atlantic cod (Gadus morhua) and 64 Greenland cod (Gadus ogac) was collected in Godthaab and Sisimiut fiord systems in West Greenland waters. All cod were dissected for stomach contents and anisakid nematodes were removed from the visceral cavity. Third stage larvae (L3) of three anisakid species were found, including Contracaecum osculatum (Rudolphi, 1802), Anisakis simplex (Rudolphi, 1809) and Hysterothylacium aduncum (Rudolphi, 1802). Molecular identification by PCR-RFLP indicated the presence of A. simplex s.s. and the sibling species C. osculatum B and C. The prevalence of infection by C. osculatum was higher in Greenland cod (84.3%) than in Atlantic cod (73.9%) whereas the prevalence of A. simplex showed an opposite pattern (Greenland cod 8.3%; Atlantic cod 24.2%). Only one G. morhua (1.0%) was infected by H. aduncum. No gender specific difference in both nematode species regarding prevalence of infection and mean infection intensity was evident, and there was no relationship between fish condition and the intensity of nematode infections. Standardised for size, capelin-eating cod were in better condition and more heavily infected than fish subsisting on alternative prey at the point of collection. Hence, nematode infections in the two gadids seem governed in part by feeding behaviour, and capelin appears a significant source of larval anisakids.

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Seasonal dynamics in feeding, organ weights, and reproductive maturation of Atlantic cod (Gadus morhua) in the southern Gulf of St Lawrence

Cited by 107 publications

References 30 publications

Spatial and temporal trends in condition of Atlantic cod Gadus morhua on the Icelandic shelf

Spatial and temporal trends in condition of Atlantic cod Gadus morhua on the Icelandic shelf

Decline and Recovery of Atlantic Cod (Gadus morhua) Stocks throughout the North Atlantic

Occurrence of anisakid nematodes in Atlantic cod (Gadus morhua) and Greenland cod (Gadus ogac), West Greenland

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