In the wild both sexes of sea bass are minimally balanced between males and females. (Photo: Georges Jansoone, csic.es)
Male sea bass proportion sought to be boosted
Wednesday, July 25, 2012, 04:40 (GMT + 9)
A team of researchers from the Centre for Marine Sciences (CCMAR) at the University of Algarve is intending to artificially balance the sex ratio of the sea bass, to inhibit the formation of males.
The main goal scientists have is to boost the production system of this species in Europe and worldwide.
While in nature the sexes are minimally balanced between males and females, in aquaculture centres there is a higher proportion of males, of nearly 90 per cent.
The problem is that the male sea bass reaches sexual maturity faster than females, and instead of using the energy from food for growth, they direct that energy to reproduction, Ciencia Hoy reported.
In economic terms, females yield much more money than males because they tend to be larger in size.
Rute Martins, a researcher at the Centre, explains that in the wild, the sea bass performs reproduction at a temperature of between 13 and 15 °C while in fish farms this stage is reached at temperatures ranging from 18 to 20 °C, and "this temperature is masculinising."
But the cost implied in cooling a farm with thousands of larvae is "simply impossible."
Therefore, the CCMAR and other European research groups have set themselves the goal of identifying those factors that are altered by temperature in order to reverse the problem.
"We have to get to know what is being affected, which is what we have been working on for the past 13 years. More specifically, in this project, we have managed to identify the genes that are being influenced by temperature," Martins added.
"We know that the temperature changes sea bass production in the first 60 days, and on these 60 days the cost of cooling water is brutal. Meanwhile, if we can be sure that the gene we are interested in or the masculinising gene is affected by temperature, we will be able to get to know exactly which are the days of the development when the specimens are sensitive to temperature," Martins explained.
Meanwhile, biologist Adelino Canário observed that "big fish farmers want large fish to sell and the meat from the fish is not as good when they start the reproductive stage," the agency Lusa reported.
This research is part of the European project 'Lifecycle', which ends in June 2013 and is funded by the European Commission (EC).
By Analia Murias