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STIPINST-Stipendiatstillinger i instituttsektoren

Stipendiatstillinger til NORCE (tidl. Uni Research) (Klima og miljø) (2017-2020)

Awarded: NOK 3.5 mill.

Early sexual maturation is undesired in salmon aquaculture, due to associated economic costs and fish welfare issues. However, new trends in Norwegian aquaculture such as producing large postsmolts in Recirculation Aquaculture Systems (RAS) under intensive rearing conditions might be contributing to this problem. This project studied how key factors manipulated during postsmolt production to optimize growth (water temperature, photoperiod, feed regime) contribute to early maturation. With this aim, Pino Martinez run three trials in freshwater. In the first, the candidate tested the effect of photoperiod manipulation (constant light or receiving a “winter signal”) on early maturation in a commercial RAS facility. In the second, Pino Martinez studied the combined effects of different temperatures (8, 12.5 or 18°C) and feed rations (Full or 67% ration) on early puberty, this time at small-scale. Finally, in the third trial the candidate examined how different temperatures (12.5 and 15°C) and photoperiods (constant light or introduction of a “winter signal”) contribute to early maturation, also at small-scale. In all trials, Pino Martinez monitored testis development and physiological indicators of maturation and smoltification. Results showed that high water temperature (18 and 15°C) was the main factor for early maturation, causing an early stimulation of the reproductive axis, and fast development and energy acquisition. Photoperiod manipulation acted as an environmental cue to synchronize initiation of the process. Feed regime had a minor impact on maturation at high temperature, and a greater impact at 12.5°C that however did not impair the process. In addition, high temperature and possibly sexual maturation negatively affected smoltification, while at low temperature (8°C) no fish matured and all seemed to smoltify. Thus, using high temperature and photoperiod manipulation can increase risk of postsmolt maturation and suboptimal development of seawater tolerance.

Prosjektet har bidratt til endringer i produksjon av settefisk laks, ved at vanntemperaturen er justert ned fra 14-15C til 10-12C. Denne reduksjonen vil bidra til at risikoen for tidlig modning hos hann fisken reduseres.

Funding scheme:

STIPINST-Stipendiatstillinger i instituttsektoren