Bacoreta post-larvae, Euthynnus alletteratus. (Photo: Francisco Alemany, IEO)
Tuna larvae cannibalism found out
Monday, October 10, 2011, 01:30 (GMT + 9)
A team of researchers at the Oceanographic Centre of the Balearic Islands from the Spanish Institute of Oceanography (IEO) and the Department of Biology from the University of Bergen (Norway) studied larvae of different tuna species and found out the development of cannibalism.
According to one of the two investigations carried out by Spanish and Norwegian experts, one of the mechanisms that can influence more on the survival of tuna larvae is cannibalism.
Furthermore, there is predation among larvae of different tuna species.
The researchers estimated that both processes would play a major role in determining larval abundance of these species during their first days of life, and would condition in this way the level of recruitment to the juvenile stages, according to IEO.
"At birth these large predators measure about three millimetres and grow rapidly, being able in less than a month to feed on smaller larvae of other tuna species or even of the same species," says Patricia Reglero, lead author of the work.
"In environments with a small number of invertebrate preys, as it occurs in almost all tuna spawning grounds in the world, the survival of various tuna species may depend on the coexistence of different-sized larvae and on the predator-prey relationship established between them," the researcher added.
The other study shows that in the Balearic Islands, which is one of the most significant bluefin tuna spawning grounds in the world, three tuna species coexist in the summer zooplankton community: bluefin, white and frigate tuna.
The research team acknowledges that when species live in heavily stocked populations, the predation and competition relationships for food among them could be important.
These studies were developed as part of the project "Larval ecology and recruitment processes of decapod crustaceans, cephalopods and teleost fish in the Balearic Sea," which is funded by the National R&D&i of the Ministry of Science and Innovation. The study will end in December next year.
By Analia Murias
Photo Courtesy of FIS Member IEO - Instituto Español de Oceanografía (Oficina central)