Final Report Summary - PERCATECH (Securing juveniles production of Eurasian perch by improving reproduction and larval rearing)
The ultimate aim of the PERCATECH project was to secure the production of Eurasian perch juveniles in order to sustain the development of European Small and medium-sized enterprises (SMEs) which funded in this new way of diversification. Considering that the juvenile availability is very low and limited to the annual cycle of reproductive period which occurs in early spring, as well as the quality of supplied juveniles is very variable this Research and development (R&D) project proposed to help the setting of a hatchery-nursery activity that other SMEs wished to develop with the aim of supporting the sustainable development of Eurasian perch production. The project mainly focused on the following:
- the assessment of the possibilities of extension of the natural reproductive period by the management of the environmental conditions;
- the optimisation of a reliable protocol allowing the induction and the control of gametogenesis in Eurasian perch and the production of out-of-season eggs and larvae with increased fertilisation rates and viability respectively;
- the comparison of the potentialities offered by the two strategies of broodstock management indicated above (extension of the natural reproductive period, out-of-season reproductive cycle);
- the identification and classification of the main factors influencing the quality of the reproduction of Eurasian perch, while considering the usual indicators of reproduction (relative spawning rate and fecundity, fertilisation, hatching rates), gametes quality and broodstock welfare, as well;
- the development of a protocol of cryogenic semen preservation;
- the understanding the biological mechanisms that lead to the high-mortality rates of the broodstock during the reproductive period;
- the definition of optimal conditions of broodstock management (especially feeding) allowing to guarantee reproductive performances and diminished mortality rates of the broodstock during the reproductive period;
- the production of domesticated strain with improved growth performance and a comparison of the growth performance of three generations of captive juvenile Eurasian perch reared under intensive conditions;
- the production of a stock of sex-reversed male completely functional and the evaluation of the productivity gain when rearing all-female populations obtained with hormonally sex-reversed male breeders;
- production of hybrids of Eurasian perch (P. fluviatilis) and yellow perch (P. flavescens) in order to compare growth performance of hybrid versus pure species under intensive rearing conditions;
- production of a triploid population in large scale and evaluation of the productivity gain when rearing diploid and triploid populations; % L - evaluation of the cost of production of a juvenile of perch according to the different production strategies and the different socio-economical contexts.
- the assessment of the possibilities of extension of the natural reproductive period by the management of the environmental conditions;
- the optimisation of a reliable protocol allowing the induction and the control of gametogenesis in Eurasian perch and the production of out-of-season eggs and larvae with increased fertilisation rates and viability respectively;
- the comparison of the potentialities offered by the two strategies of broodstock management indicated above (extension of the natural reproductive period, out-of-season reproductive cycle);
- the identification and classification of the main factors influencing the quality of the reproduction of Eurasian perch, while considering the usual indicators of reproduction (relative spawning rate and fecundity, fertilisation, hatching rates), gametes quality and broodstock welfare, as well;
- the development of a protocol of cryogenic semen preservation;
- the understanding the biological mechanisms that lead to the high-mortality rates of the broodstock during the reproductive period;
- the definition of optimal conditions of broodstock management (especially feeding) allowing to guarantee reproductive performances and diminished mortality rates of the broodstock during the reproductive period;
- the production of domesticated strain with improved growth performance and a comparison of the growth performance of three generations of captive juvenile Eurasian perch reared under intensive conditions;
- the production of a stock of sex-reversed male completely functional and the evaluation of the productivity gain when rearing all-female populations obtained with hormonally sex-reversed male breeders;
- production of hybrids of Eurasian perch (P. fluviatilis) and yellow perch (P. flavescens) in order to compare growth performance of hybrid versus pure species under intensive rearing conditions;
- production of a triploid population in large scale and evaluation of the productivity gain when rearing diploid and triploid populations; % L - evaluation of the cost of production of a juvenile of perch according to the different production strategies and the different socio-economical contexts.