Modeling growth of Atlantic cod larvae on the southern flank of Georges Bank in the tidal-front circulation during May 1999

A transect across southern Georges Bank in May 1983 showed higher levels of available prey for haddock (Melanogrammus aeglefinus) and cod (Gadus morhua) larvae at two stratified sites than at a well-mixed site. At the stratified sites, prey biomass was high (30–300 μg dry wt∙L−1) near the surface above the thermocline; values were lower and more uniform with depth (10–30 μg dry wt∙L−1) at the well-mixed site. Larval population centers generally coincided with prey biomass vertically. Recent growth in dry weight of haddock larvae as estimated by RNA–DNA ratio analysis was higher at the stratified sites (8–13%∙d−1) than at the well-mixed site (7%∙d−1). Larvae appeared to be in excellent condition at the stratified sites, but up to 50% of haddock larvae from the well-mixed site had RNA–DNA ratios in the range observed for starved larvae in the laboratory. Cod collected at the same site were in better condition and growing faster than haddock. The data support the hypotheses that (1) stratified conditions in the spring favor good growth and survival of haddock larvae and (2) cod larvae are better adapted to grow and survive in well-mixed waters at lower levels of available food than haddock larvae.

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Small-scale temporal and spatial variation in Atlantic cod (Gadus morhua) life history

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f03-090 ◽

2003 ◽

Vol 60 (9) ◽

pp. 1111-1121 ◽

Cited By ~ 44

Author(s):

Tara M McIntyre ◽

Jeffrey A Hutchings

Keyword(s):

Body Mass ◽

Life Histories ◽

Gadus Morhua ◽

Atlantic Cod ◽

Spatial Scales ◽

Gonadosomatic Index ◽

Small Scale ◽

Hepatosomatic Index ◽

Georges Bank ◽

High Fecundity

Life histories of Atlantic cod (Gadus morhua) from the Gulf of St. Lawrence south to Georges Bank differ significantly through time and space. Within the Southern Gulf, fecundity per unit body mass differed by more than 40% over short (2 years) and long (4245 years) periods of time. Significant variation in size-specific fecundity is also evident among populations: Southern Gulf cod produce almost 30% more eggs per unit body mass than those on Georges Bank, whereas fecundity of Scotian Shelf cod is almost half that of cod in Sydney Bight. Compared with those on Georges Bank, Southern Gulf cod life histories are characterized by high fecundity, late maturity, high gonadosomatic index, and large eggs. Relative to the influence of body size, neither temporal nor spatial differences in fecundity can be attributed to physiological condition, as reflected by liver weight, hepatosomatic index, and Fulton's K. Delayed maturity and higher reproductive allotment among Southern Gulf cod can be explained as selection responses to slower growth, higher prereproductive mortality, and fewer lifetime reproductive events. Patterns of covariation in heritable, fitness-related traits suggest the existence of adaptive variation and evolutionarily significant units at spatial scales considerably smaller than the species range in the Northwest Atlantic.

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Changes in natural mortality of Atlantic cod (Gadus morhua) on Eastern Georges Bank

Journal of Ocean University of China ◽

10.1007/s11802-016-3019-4 ◽

2016 ◽

Vol 15 (5) ◽

pp. 879-889

Author(s):

Yanjun Wang

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

Natural Mortality ◽

Georges Bank

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Using Fishermen’s Ecological Knowledge to map Atlantic cod spawning grounds on Georges Bank

ICES Journal of Marine Science ◽

10.1093/icesjms/fsx031 ◽

2017 ◽

Vol 74 (6) ◽

pp. 1587-1601 ◽

Cited By ~ 8

Author(s):

Gregory R. DeCelles ◽

David Martins ◽

Douglas R. Zemeckis ◽

Steven X. Cadrin

Keyword(s):

Atlantic Cod ◽

Temporal Distribution ◽

Scientific Data ◽

Ecological Knowledge ◽

Detailed Knowledge ◽

Spatial And Temporal Distribution ◽

Georges Bank ◽

Spawning Activity ◽

Spawning Grounds ◽

Holistic Understanding

Abstract The spawning dynamics of Atlantic cod (Gadus morhua) on Georges Bank and Nantucket Shoals are not well understood. To address this uncertainty, we combined Fishermen’s Ecological Knowledge (FEK) with traditional scientific data to develop a more holistic understanding of cod spawning on Georges Bank. Data from historical reports, trawl surveys, fisheries observers, and ichthyoplankton surveys were used to describe the spatial and temporal distribution of cod spawning activity. We also collected FEK regarding cod spawning dynamics through semi-structured interviews (n = 40). The fishermen had detailed knowledge of the spatial and temporal distribution of cod spawning, and identified persistent fine-scale (i.e. <50 km2) spawning grounds that were often associated with specific habitat features, including spawning grounds that were previously unreported in the scientific literature. The spawning seasons and locations identified by fishermen generally agreed with information from traditional scientific data, but it was evident that seasonal scientific surveys lack the spatial and temporal resolution needed to fully characterize the distribution of cod spawning activity. Our results will help inform management measures designed to promote the rebuilding of Georges Bank cod, and also provide a basis for further investigations of cod spawning dynamics and stock structure.

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Use of the microalga Pavlova viridis as enrichment product for the feeding of Atlantic cod larvae (Gadus morhua)

Aquaculture ◽

10.1016/j.aquaculture.2015.01.011 ◽

2015 ◽

Vol 438 ◽

pp. 141-150 ◽

Cited By ~ 9

Author(s):

S. Rehberg-Haas ◽

S. Meyer ◽

M. Tielmann ◽

S. Lippemeier ◽

O. Vadstein ◽

...

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

Pavlova Viridis ◽

Atlantic Cod Larvae ◽

Enrichment Product

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Bacterial community assembly in Atlantic cod larvae (Gadus morhua): contributions of ecological processes and metacommunity structure

FEMS Microbiology Ecology ◽

10.1093/femsec/fiaa163 ◽

2020 ◽

Vol 96 (9) ◽

Cited By ~ 1

Author(s):

Ragnhild I Vestrum ◽

Kari J K Attramadal ◽

Olav Vadstein ◽

Madeleine Stenshorne Gundersen ◽

Ingrid Bakke

Keyword(s):

Community Assembly ◽

Bacterial Communities ◽

Atlantic Cod ◽

Animal Health ◽

Striking Difference ◽

Ecological Processes ◽

Opportunistic Bacteria ◽

Atlantic Cod Larvae ◽

Microbe Interactions ◽

Host Microbe Interactions

ABSTRACT Many studies demonstrate the importance of the commensal microbiomes to animal health and development. However, the initial community assembly process is poorly understood. It is unclear to what extent the hosts select for their commensal microbiota, whether stochastic processes contribute, and how environmental conditions affect the community assembly. We investigated community assembly in Atlantic cod larvae exposed to distinct microbial metacommunities. We aimed to quantify ecological processes influencing community assembly in cod larvae and to elucidate the complex relationship between the bacteria of the environment and the fish. Selection within the fish was the major determinant for community assembly, but drift resulted in inter-individual variation. The environmental bacterial communities were highly dissimilar from those associated with the fish. Still, differences in the environmental bacterial communities strongly influenced the fish communities. The most striking difference was an excessive dominance of a single OTU (Arcobacter) for larvae reared in two of the three systems. These larvae were exposed to environments with higher fractions of opportunistic bacteria, and we hypothesise that detrimental host–microbe interactions might have made the fish susceptible to Arcobacter colonisation. Despite strong selection within the host, this points to a possibility to steer the metacommunity towards mutualistic host–microbe interactions and improved fish health and survival.

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