scholarly journals Changes in Atlantic cod (Gadus morhua L.) sperm quality during the spawning season

2008 ◽  
Vol 39 (4) ◽  
pp. 434-440 ◽  
Author(s):  
Catherine Rouxel ◽  
Marc Suquet ◽  
Jacky Cosson ◽  
Armelle Severe ◽  
Loic Quemener ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Sperm Quality ◽  
Spawning Season

Peculiarities in ovarian structure leading to multiple-year delays in oogenesis and possible senescence in Atlantic cod, Gadus morhua L.

2000 ◽  
Vol 78 (10) ◽  
pp. 1840-1844 ◽  
Author(s):  
Rick M Rideout ◽  
Margaret PM Burton
Keyword(s):  
Atlantic Ocean ◽  
Reproductive Cycle ◽  
Gadus Morhua ◽  
East Coast ◽  
Atlantic Cod ◽  
Spawning Season ◽  
Northwest Atlantic ◽  
Spawning Cycle ◽  
Ovarian Structure

Five specimens of female Atlantic cod, Gadus morhua L., four collected during regular surveys of the northwest Atlantic Ocean, had ovarian structures that suggested that multiple-year interruptions were occurring in the spawning cycle of these fish. One specimen was experiencing a minimal 2-year delay in its reproductive cycle because the ovary contained only oogonia, which would have had to mature before any spawning could occur. Two other specimens did not contain oogonia or perinucleolar-stage oocytes, suggesting that these ovaries were senescent. Another two ovaries, one removed from a broodstock female and one taken from a female collected off Newfoundland's east coast, contained large masses of resorbing hyaline oocytes, which would likely have impaired the normal release of hydrated oocytes in the next spawning season.

scholarly journals Home range and elevated egg densities within an inshore spawning ground of coastal cod

2007 ◽  
Vol 64 (5) ◽  
pp. 920-928 ◽  
Author(s):  
Sigurd Heiberg Espeland ◽  
Ailin Fernløf Gundersen ◽  
Esben Moland Olsen ◽  
Halvor Knutsen ◽  
Jakob Gjøsæter ◽  
...  
Keyword(s):  
Home Range ◽  
Site Fidelity ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Generalized Additive Models ◽  
Spatial Dynamics ◽  
Additive Models ◽  
Spawning Season ◽  
Spawning Ground ◽  
Spawning Site

Abstract Espeland, S. H., Gundersen, A. F., Olsen, E. M., Knutsen, H., Gjøsæter, J., and Stenseth, N. C. 2007. Home range and elevated egg densities within an inshore spawning ground of coastal cod. – ICES Journal of Marine Science, 64: 920–928. Atlantic cod (Gadus morhua) along the Norwegian Skagerrak coast are structured into genetically distinct local populations. Mechanisms contributing to this genetic structure may include spawning site fidelity of adult cod as well as retention of pelagic early life stages close to the spawning grounds. Spawning in sheltered inshore localities is likely to favour retention of eggs and larvae, the opposite situation to offshore spawning. A combined study was made of area utilization by adult cod and the distribution of cod eggs within an inshore locality of the Norwegian Skagerrak coast. The behaviour of adult cod was studied using acoustic telemetry and kernel modelling, and eggs were sampled throughout the spawning season. Generalized additive models were applied to test hypotheses about the spatial dynamics of the eggs, and the best model described a central spawning area that retained its integrity through time. Adult cod were confined to small parts of the study area and remained there throughout the spawning season. The average home range of the adult cod was 27 ha. Overall, the study demonstrated two mechanisms by which coastal (i.e. inshore) cod maintain their population structure: spawning site fidelity and the spatial dynamics of their eggs.

Sperm competition and fertilization success in Atlantic cod (Gadus morhua): effect of sire size and condition factor on gamete quality

1999 ◽  
Vol 56 (12) ◽  
pp. 2315-2323 ◽  
Author(s):  
Ana Rakitin ◽  
Moira M Ferguson ◽  
Edward A Trippel
Keyword(s):  
Body Size ◽  
Sperm Competition ◽  
Gadus Morhua ◽  
Condition Factor ◽  
Atlantic Cod ◽  
Sperm Quality ◽  
Fertilization Success ◽  
Male Body ◽  
Single Female ◽  
Male Condition

Sperm competition experiments were conducted to test the null hypothesis that sperm quality is not affected by male body size in Atlantic cod (Gadus morhua). Genetic markers (allozymes) were used to determine the proportion of larvae sired by pairs of males when their sperm was combined with eggs of a single female simultaneously. Significant differences in fertilization success between males were not explained by differences in body size. Fertilization success was positively associated with male condition factor (K) and with spermatozoa density in each male's semen when equal volumes of semen from each male were used. Male K was positively associated with male fertilization success when the volume of semen used from each male was adjusted to add approximately equal numbers of spermatozoa from each male. The relative fertilization success of males varied depending on which female was the egg donor, suggesting that female "choice" at the gamete level may be occurring in cod.

Fertility and Sperm Quality of Virgin and Repeat-Spawning Atlantic Cod (Gadus morhua) and Associated Hatching Success

1992 ◽  
Vol 49 (10) ◽  
pp. 2118-2127 ◽  
Author(s):  
Edward A. Trippel ◽  
John D. Neilson
Keyword(s):  
Gadus Morhua ◽  
Hatching Success ◽  
Atlantic Cod ◽  
Sperm Quality ◽  
High Capacity ◽  
Video Camera ◽  
Grid Pattern ◽  
Mean Values ◽  
High Prevalence ◽  
Total Variability

Sperm performance of virgin and repeat spawners of Atlantic cod (Gadus morhua) was compared. Our results indicate that sperm extracted from either virgin or repeat-spawning male cod exhibit a high capacity (usually >95%) to fertilize eggs at semen:seawater dilutions ranging from 1:1 to 1:100. Fertilization rates at higher dilutions, however, decreased to averages of 47 and 53% at 1:1000, with no statistically significant differences occurring betwen the two types of spawners. Spermatocrit and proportion of sperm cells exhibiting progressive forward motion together accounted for, at most, 14% of the total variability in success of fertilization at semen:seawater dilutions of 1:250, 1:500, and 1:1000. Individuals of both spawner types had immotile sperm, sometimes at high prevalence levels, but these individuals achieved fertiliztion rates comparable with those with high sperm motility. Hatching success of eggs fertilized by virgin males was more variable but, based on mean values, was almost identical to that of repeat spawners. Use of a video camera to record enlarged images of sperm with a haemacytometer grid pattern in the background has permitted the first documented measurements of sperm swimming speeds of a marine teleost fish; the fastest recorded speed was 1000 μm∙30 s−1.

Multiyear homing of Atlantic cod to a spawning ground

2001 ◽  
Vol 58 (12) ◽  
pp. 2325-2329 ◽  
Author(s):  
D Robichaud ◽  
G A Rose
Keyword(s):  
North Atlantic ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spawning Season ◽  
Spawning Ground ◽  
Long Distance ◽  
Tag Loss ◽  
Sea Bed ◽  
Placentia Bay

Long-term sonar transmitting tags were implanted in 27 female and 21 male cod (Gadus morhua) at the Bar Haven spawning ground in Placentia Bay, Newfoundland, in April 1998. Two thirds of tagged fish were relocated. All relocations during the 1999 and 2000 spawning seasons were within 10 km of the tagging site, the majority being within a few hundred metres. No tagged fish were relocated at other spawning grounds or elsewhere in the bay during the spawning season. Outside the spawning season, several tagged fish were relocated in other parts of the bay at ranges of a few kilometres to 110 km from the tagging site, as were 13 of 15 fishery returns (2 returns from several hundred kilometres outside the bay). Homing rates in 1999 and 2000 were 39% and 53%, respectively, after adjustments for tag loss, mortality, misreporting, and relocation efficiency based on returns from a sea-bed beacon tag left at the Bar Haven grounds. Multiyear homing was observed in 26% of cod. This study provides the first direct evidence that cod undertaking long-distance feeding migrations may home to a specific spawning ground in consecutive years, and a hypothesis for the slow recolonisation rates observed in North Atlantic cod stocks.

Spermatocrit and spermatozoa density in Atlantic cod (Gadus morhua): correlation and variation during the spawning season

Aquaculture ◽  
1999 ◽  
Vol 170 (3-4) ◽  
pp. 349-358 ◽  
Author(s):  
Ana Rakitin ◽  
Moira M Ferguson ◽  
Edward A Trippel
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spawning Season

scholarly journals Atlantic cod (Gadus morhua) feed during spawning off Newfoundland and Labrador

2012 ◽  
Vol 69 (10) ◽  
pp. 1701-1709 ◽  
Author(s):  
Kyle J. Krumsick ◽  
George A. Rose
Keyword(s):  
Newfoundland And Labrador ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stomach Contents ◽  
Northern Region ◽  
Spawning Season ◽  
Northern Regions ◽  
Consumption Rates ◽  
Spawning Behaviour ◽  
Behaviour Models

Abstract Krumsick, K. J., and Rose, G. A. 2012. Atlantic cod (Gadus morhua) feed during spawning off Newfoundland and Labrador. – ICES Journal of Marine Science, 69: 1701–1709. We test a current assumption that Atlantic cod (Gadus morhua) off Newfoundland and Labrador, Canada, do not feed during the protracted spawning season (March–September). Stomach contents were analysed from 10 473 cod from four Northwest Atlantic Fisheries Organization regions (2J, 3K, 3L, and 3Ps) over 9 years from which gonads were also analysed to determine sex and maturity status. Adult cod in spawning condition did feed in all regions, usually at rates equivalent to or even greater than non-spawning fish and juveniles. Both sexes fed during spawning, though females consumed lesser amounts. Regional differences were evident. The total fullness index was greater in the northern (2J) than the southern (3Ps) region, with no consistent differences between spawners and non-spawners. The most southerly region (3Ps) exhibited the greatest prey diversity, the northern region (2J) the least. Shrimp was the major diet item in the northern regions. Capelin, zooplankton, crab, and other fish increased in importance to the south. Differences in prey items between non-spawning and spawning individuals of both sexes were possibly related to spawning behaviour. Models using consumption rates should not assume that cod do not feed during the protracted spawning season in these waters.

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