Sperm Metabolism and Biochemical Characteristics in First‐Time and Second‐Time Spawners of Farmed Atlantic Cod

Abstract

We compared sperm biochemical characteristics of first‐generation (F1) hatchery‐reared broodstock of Atlantic cod Gadus morhua during the first and second spawnings to investigate potential improvements in sperm quality between the two spawning events. To gain further perspective on the sperm characteristics investigated, the values for farmed Atlantic cod were also compared with sperm characteristics of wild, experienced spawners that had been kept captive for 4 years. In particular, we investigated differences in the lactate dehydrogenase (glycolytic metabolism) and lipase (lipid catabolism) enzyme activities as well as sperm respiration rates and energy levels. Fertilization percentages for the F1 hatchery males at the first and second spawnings and for the wild broodstock were also obtained. The wild broodstock males were older and larger than the farmed males and produced sperm with higher energy levels, protein levels, and fertilization rates relative to the sperm of farmed naïve spawners. Our results showed no differences in characteristics between the first and second spawnings and seemed to contradict previous findings that demonstrated an improvement between first and second spawnings in captive wild Atlantic cod. Further investigations on sperm of hatchery‐reared Atlantic cod broodstock (e.g., sperm motility; fertilization rates of the same males) are necessary to confirm the present findings.

Spawning Dynamics and Associated Management Implications for Atlantic Cod

“…Sperm volume and male fertilization success are thought to be unrelated to fish size or reproductive experience (Trippel and Neilson 1992;Trippel and Morgan 1994;Hamoutene et al 2011). In contrast, female gamete size is positively correlated with fish size (Chambers and Waiwood 1996;Marteinsdottir and Steinarsson 1998) and repeat spawners produce significantly larger eggs (Vallin and Nissling 2000) with greater spawning intervals (Kjesbu et al 1996) and fertilization rates (Trippel 1998).…”