Neuroendocrine regulation of reproduction in Atlantic cod (Gadus morhua): Evidence of Eya3 as an integrator of photoperiodic cues and nutritional regulation to initiate sexual maturation

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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Highly unsaturated fatty acid synthesis in marine fish: Cloning, functional characterization, and nutritional regulation of fatty acyl Δ6 desaturase of Atlantic cod (Gadus morhua L.)

Lipids ◽

10.1007/s11745-006-5051-4 ◽

2006 ◽

Vol 41 (11) ◽

pp. 1003-1016 ◽

Cited By ~ 151

Author(s):

Douglas R. Tocher ◽

Xiaozhong Zheng ◽

Christian Schlechtriem ◽

Nicola Hastings ◽

James R. Dick ◽

...

Keyword(s):

Fatty Acid ◽

Unsaturated Fatty Acid ◽

Gadus Morhua ◽

Atlantic Cod ◽

Functional Characterization ◽

Acid Synthesis ◽

Fatty Acyl ◽

Highly Unsaturated Fatty Acid ◽

Nutritional Regulation ◽

Δ6 Desaturase

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Family differences on triploid induction, sexual maturation and its contribution to sea cage performance of Atlantic cod, Gadus morhua

Aquaculture ◽

10.1016/j.aquaculture.2019.03.013 ◽

2019 ◽

Vol 506 ◽

pp. 14-22

Author(s):

Velmurugu Puvanendran ◽

Ingrid Lein ◽

Rama Bangera ◽

Atle Mortensen ◽

Anders Thorsen

Keyword(s):

Sexual Maturation ◽

Gadus Morhua ◽

Atlantic Cod ◽

Sea Cage

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Continuous light delays sexual maturation and increases growth of Atlantic cod (Gadus morhua L.) in sea cages

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2005.10.014 ◽

2006 ◽

Vol 63 (2) ◽

pp. 365-375 ◽

Cited By ~ 73

Author(s):

G.L. Taranger ◽

L. Aardal ◽

T. Hansen ◽

O.S. Kjesbu

Keyword(s):

Sexual Maturation ◽

Gadus Morhua ◽

Atlantic Cod ◽

Gonad Development ◽

Somatic Growth ◽

Continuous Light ◽

Reproductive Investment ◽

Spawning Season ◽

Commercial Fish ◽

Spawning Period

Abstract Prevention of early sexual maturation is essential in Atlantic cod (Gadus morhua) farming because maturity results in reduced growth, affects flesh quality, and may lead to increased mortality. In farmed cod, almost 100% of the fish mature at two years of age and often at a size of 1.5–2 kg. Two pilot experiments were conducted with cod in sea cages at a commercial fish farm in western Norway (60°N) to test the effect of additional continuous light (LL) on the timing of sexual maturation and somatic growth compared with controls under natural light (NL). In the NL groups, 100% maturation was indicated during the natural spawning period from February to April at the age of two years. By contrast, LL treatment from 27 June (15-month-old cod) or 2 September (18-month-old cod) onwards delayed gonad development by three to five months, reduced reproductive investment, and enhanced winter growth compared with the controls. Fish held at NL decreased in body weight during the spawning season (February–April), whereas LL-exposed fish appeared to continue to grow during their spawning season (May–August). LL-treated cod reached mean body weights of 2.90–3.13 kg within 28 months of hatching, whereas the controls reached 2.20–2.42 kg during the same period.

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