Tuna parasites. (Photo: Salvatore Mele/IEO)
Parasites, Mediterranean tuna natural markers
Friday, October 19, 2012, 23:00 (GMT + 9)
A team of researchers from the Spanish Institute of Oceanography (IEO) and the University of Sassari (Sardinia, Italy) studied the biology and ecology of the Mediterranean tuna through the analysis of their parasites, which act as natural markers.
"It is fascinating to consider how thousands and thousands of species of parasites have managed to evolve in a balanced way with their hosts, in such an intimate relationship that scientists call it co-evolution," explains Salvatore Mele, lead author of the research, which was published recently.
In some cases, the parasite needs a specific host to breed and very specific environmental conditions to maintain the levels of infection. And some require the presence of several hosts in which to develop the different phases of their life cycle, IEO reported.
Therefore, their survival depends on a set of species.
Given the characteristics of the tuna, which performs long oceanic migrations, habitat changes may affect the presence of parasites. This applies both to ectoparasites (which are in direct contact with the marine environment) and to endoparasites (living in the host’s organs and tissues).
Environmental changes and the presence or absence of intermediate hosts among the different host distribution areas can make a difference in all of these tuna’s parasites.
The scientists who conducted the study believe that it may be useful to obtain data on the biology, ecology and migratory patterns of the specimens.
"Parasitological studies have some advantages over the use of the artificial marking," Mele adds.
"For example, they enable the study of deep-sea species without having to face decompression issues, and the routine analysis of samples captured in scientific and commercial surveys without recapturing the fish, thus limiting costs," states the researcher.
However, IEO stresses that the limited information available on the parasitic fauna of tuna from the Mediterranean Sea and from other waters hampers the studies and the possibility of obtaining relevant and reliable conclusions.
By Analia Murias
Photo Courtesy of FIS Member IEO - Instituto Español de Oceanografía (Oficina central)