Effect of Photoperiod Manipulation on Broodstock Spawning, Fertilization Success, and Egg Developmental Abnormalities in Atlantic Cod, Gadus morhua

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.

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The role of seasonally altering photoperiod in regulating physiology in Atlantic cod (Gadus morhua). Part I. Sexual maturation

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f06-169 ◽

2007 ◽

Vol 64 (1) ◽

pp. 84-97 ◽

Cited By ~ 49

Author(s):

Andrew Davie ◽

Mark JR Porter ◽

Niall R Bromage ◽

Herve Migaud

Keyword(s):

Sexual Maturation ◽

Gadus Morhua ◽

Atlantic Cod ◽

Reproductive Activity ◽

Continuous Illumination ◽

Natural Photoperiod ◽

Artificial Photoperiod ◽

Commercially Important ◽

Photoperiod Manipulation

While the Atlantic cod (Gadus morhua) displays clear seasonality in its reproductive cycle, the exact photic signal that entrains this rhythm is yet undefined. This present work developed a model to describe the photic regulation of reproduction in the species in comparison with other commercially important temperate teleosts. This was achieved through the strategic masking of the natural photoperiod cycle during the first 2 years of life with the application of continuous illumination. The results demonstrated that it is the falling autumnal photoperiod signal after the summer solstice, more specifically after October, that is responsible for recruiting individuals to enter the sexual maturation cycle. Furthermore, in all treatments where this signal was masked through the application of continuous illumination, there was no significant reproductive activity and growth was improved by up to 60% at 27 months posthatch. This information is of particular value to the developing cod aquaculture industry in which the management of reproduction using artificial photoperiod manipulation will be of vital economic importance.

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The effect of sperm to egg ratio and gamete contact time on fertilization success in Atlantic cod Gadus morhua L.

Aquaculture ◽

10.1016/j.aquaculture.2008.09.005 ◽

2009 ◽

Vol 286 (1-2) ◽

pp. 89-94 ◽

Cited By ~ 55

Author(s):

Ian A.E. Butts ◽

Edward A. Trippel ◽

Matthew K. Litvak

Keyword(s):

Contact Time ◽

Gadus Morhua ◽

Atlantic Cod ◽

Fertilization Success ◽

Egg Ratio

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Fertilization success and blastomere morphology as predictors of egg and juvenile quality for domesticated Atlantic cod, Gadus morhua, broodstock

Aquaculture Research ◽

10.1111/j.1365-2109.2010.02506.x ◽

2010 ◽

Vol 41 (12) ◽

pp. 1791-1798 ◽

Cited By ~ 17

Author(s):

Øyvind Johannes Hansen ◽

Velmurugu Puvanendran

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

Fertilization Success

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Sperm motility patterns of Atlantic cod (Gadus morhua) in relation to salinity: effects of ovarian fluid and egg presence

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f98-093 ◽

1998 ◽

Vol 55 (8) ◽

pp. 1871-1877 ◽

Cited By ~ 53

Author(s):

Matthew K Litvak ◽

Edward A Trippel

Keyword(s):

Sperm Motility ◽

Gadus Morhua ◽

Atlantic Cod ◽

Fertilization Success ◽

Salinity Range ◽

Motile Sperm ◽

Maternal Factors ◽

Ovarian Fluid ◽

Salinity Effects ◽

Significant Difference

A significantly greater proportion of Atlantic cod (Gadus morhua) sperm were motile in the presence of ovarian fluid and egg compared with seawater. Sperm mean and maximum swimming speeds were also significantly greater in the presence of ovarian fluid and egg compared with seawater. However, there was no significant difference in path linearity among treatments. We also examined the interaction between maternal stimuli (egg and ovarian fluid), time sperm spent in seawater prior to exposure to each stimulus, and salinity on proportion of motile sperm and their swimming behaviours. Proportion of motile sperm decreased significantly with a decrease in salinity in the presence of both maternal stimuli. Proportion of motile sperm also decreased with time spent in seawater prior to exposure to ovarian fluid but not to an egg. Both mean and maximum swimming speeds were maintained in the salinity range of 20-30 ppt and only declined significantly at lower salinities (15 and 17.5 ppt). Mean and maximum swimming speeds decreased with time spent in seawater. This study demonstrates the importance of maternal factors when examining sperm swimming behaviour and highlights the significance of maternal-paternal gametic interactions in understanding fertilization success.

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