Evolutionary pressure on reproductive strategies in flatfish and groundfish: Relevant concepts and methodological advancements
Kjesbu, O.S.; Witthames, P.R. (2007). Evolutionary pressure on reproductive strategies in flatfish and groundfish: Relevant concepts and methodological advancements. J. Sea Res. 58(1): 23-34. https://dx.doi.org/10.1016/j.seares.2007.02.001 In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more Also appears in:Yamashita, Y.; Nash, R.D.M.; van der Veer, H.W. (Ed.) (2007). Proceedings of the Sixth International Symposium on Flatfish Ecology, Part II, held at Maizuru, Kyoto, Japan from 20-25 October 2005. Journal of Sea Research, 58(1). Elsevier: Amsterdam. 1-112 pp., more |  |
| Keywords | Biological phenomena > Evolution
Population functions > Growth
Properties > Biological properties > Fecundity
Properties > Biological properties > Sexual maturity
Reproduction
Reproductive cycle
Seasons > Spawning season
Spawning seasons
Gadus morhua Linnaeus, 1758 [WoRMS]; Hippoglossus hippoglossus (Linnaeus, 1758) [WoRMS]; Pleuronectes platessa Linnaeus, 1758 [WoRMS]; Scophthalmus maximus (Linnaeus, 1758) [WoRMS]; Solea solea (Linnaeus, 1758) [WoRMS]
Marine/Coastal | | Author keywords | reproduction; maturation; reaction norm; fecundity; sperm; spawningseason; cod; plaice; sole; turbot |
| Authors | | Top | - Kjesbu, O.S.
- Witthames, P.R.
| | |
| Abstract | Flatfish and groundfish show many similarities in reproductive strategies and tactics, both in types present and in responses to fishing pressure or changes in their environment. Over the last 20-30 years the reproduction of Atlantic cod Gadus morhua, Atlantic halibut Hippoglossus hippoglossus, plaice Pleuronectes platessa, sole Solea solea, and turbot Scophthalmus maximus have been extensively studied in the North Atlantic. For cod, halibut and turbot, the research has progressed rapidly due to interest from the aquaculture industry. Extensive overexploitation over many years in combination with climate change represents a potential evolutionary pressure towards changes in growth, lower age at maturity, increased fecundity, smaller egg size (and thereby larval size) and change in spawning time. Early sexual maturity/precocious maturation is also seen in aquaculture and is problematic economically due to a reduction in fillet production. In this paper information is reviewed from studies on both wild and captive populations in experiments, the latter considered important because overexploitation, such as observed in the North Sea, often reduces the natural dynamics in growth and reproduction and complicates collection of sufficiently large samples. Evidence from laboratory experiments demonstrates the inherent plasticity of fecundity production and how this is controlled by food availability and length of photoperiod, while recent information from field studies demonstrates the evolution of genotypes in response to fishing mortality. Today several laboratories have adopted modern techniques for analysis of reproductive investments (fecundity, atresia and sperm characterisation) in controlled experimental situations to explore the effect of temperature or other environmental parameters (such as salinity) on reproduction. These developments, in combination with the rapid implementation of molecular techniques, should make it possible in the future to present highly precise information on reproductive potential, both at the individual and stock level. Of particular interest, and a major goal, would be to dissociate genetic and phenotypic control of reproductive traits arising from a better understanding of gene expression in captive populations. |
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