Temperature-dependent development rates of cod Gadus morhua eggs

• Published in: Journal of fish biology 2006-10, Vol.69 (4), p.1060-1080
• Main Authors: Geffen, A. J., Fox, C. J., Nash, R. D. M.
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Biological and medical sciences; developmental stages; egg development; egg quality; Fundamental and applied biological sciences. Psychology; gadoids; Gadus morhua; Marine; stage duration; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
• ISSN: 0022-1112; 1095-8649
• DOI: 10.1111/j.1095-8649.2006.01181.x

Temperature development relationships were determined for batches of Irish Sea cod Gadus morhua eggs incubated in flow‐through incubators. Hatching began 16·4 days after fertilization (DAF) at 6° C, 10·3 DAF at 8° C, 9·4 DAF at 10° C and 7·4 DAF at 12° C. Egg mortality increased at the higher temperatures, but survival was >80%. Results were compared with published data at four comparable stage end points: the end of blastula, the end of gastrula, the point of growth of the embryo completely surrounding the yolk and the point when 50% of the eggs were hatched. All the studies showed a curvilinear relationship between age at stage and temperature. There was a 12 day inter‐study difference in time to 50% hatch at 2° C and 4 day difference at 10° C. There were no consistent trends that differentiated eastern v. western, or northern v. southern populations. A single model for cod egg incubation time from fertilization to 50% hatch was derived based on data from six cod populations, but it is recommended that individual stock relationships should be used where possible.