Cages used for marine fish farming. (Photo: Stock File)
Completion of farming cycle a challenge for researchers
Wednesday, February 23, 2011, 05:20 (GMT + 9)
A team of scientists from the Spanish Institute of Oceanography (IEO) are conducting research to try to complete the whole farming cycle for 12 marine species. The goal is to get breeders from captivity, to avoid dependence on the natural environment.
In the case of sole, for example, they have not yet succeeded in completing the entire cultivation process, therefore the companies that market it are forced to capture the species and then fatten it before offering it on the market.
According to José Benito Pelerin, a Galician researcher at the Aquaculture Area of the IEO, "an installation is cost effective when breeders lay eggs all year round, allowing for the continuous availability of juveniles for farming," reports Faro de Vigo.
The main species currently under investigation in Spain - and in Galicia particularly - include pollock, eel, bluefin tuna, snapper, wreckfish, Senegalese sole, hake, grouper and octopus.
With regards to pollock, researchers are working to achieve profitable production despite having a major drawback: the fish reach sexual maturity before they reach commercial size.
While the company Isidro de la Cal has been focused on the production of pollock for a while, they finally gave up due to their early maturity.
Peleteiro explained that the study focuses on sterile pollock so that sexual maturity does not affect their growth.
In connection with the eel, he said that captive breeding is difficult and everything that is produced for the market comes after their capture from the wild and subsequent fattening.
Meanwhile, they managed to put bluefin tuna in captivity and carry out the first test for fattening in cages.
Snapper is "midway" through consolidation, as it is on the market since 2000 and research is focused on achieving faster growth.
With regards to wreckfish, Peleteiro reported that studies in the Atlantic Ocean and the Mediterranean Sea support the viability of this species, but the biggest problem is that it does not reach sexual maturity until 10 kg.
The great advantage of this resource is that it has spectacular fattening: 6 to 8 kilos per year, "which in our aquaculture is extraordinary," added the scientist.
Moreover, Senegalese sole is already in the market, but production companies depend on wild catches.
The biggest obstacle to close its cultivation is captive breeding, so they must resort to catches at sea and their subsequent fattening.
In connection with hake, there broodstock adapted to captivity and are proven to grow rapidly. The researchers aim to obtain juveniles for fattening, though one of the biggest problems is its sensitivity to management.
As for the grouper, experts, mainly from southern Spain, managed natural reproduction and are now able to conduct fattening in tanks and cages at sea.
According to Peleteiro, grouper is one of the most promising aquaculture speacies to diversify its growth and consumer demand.
Meanwhile, he stressed that the octopus has the advantage of growing fast: one kilo per month once it reaches 500 grams. There are research groups in Galicia, the Canary Islands and the Mediterranean, but the main obstacle to production is the high mortality in the juvenile stage.
Species which have already had the farming production cycle completed are turbot, seabass and seabream, which are the main products of the aquaculture industry in Spain.
By Analia Murias