Parasites as biological tags for identification of fish populations and viceversa?

CANTATORE, D.M.P.; IRIGOITIA, M.M.; TIMI, J.T.

Texel

Simposio; International Symposium on Ecology and Evolution of marine parasites & diseases; 2014

Royal Netherlands Institute for Sea Research (NIOZ) and Alfred Wegner Institute for Polar and Marine Research (AWI).

The use of parasites as biological tags for fish population assessment is a widely applied methodology based in comparisons of parasite populations and communities across fish samples in a geographical context. A series of biological tags studies carried out in the southwestern Atlantic showed that their parasite assemblages are largely dominated by larval helminth species that share a low specificity, parasitizing almost indiscriminately all available fish species. Their individual geographic distributions are reflected on recurrent clines across fish species and zoogeographical regions in the Argentine Sea, leading to hypothesize that not only fish stocks, but also fish assemblages might be identified according to their occurrence. Therefore, shifting the focus from fish populations to communities, the concept of biological tags can be expanded to a broader scale, making them suitable as regional biological tags. Furthermore, inverting the analyses, fish samples can be thought as biological tags for identification of parasite populations and communities; which, in turn, can be used as markers of the regions or masses of waters they inhabit and, consequently, as ecosystem indicators. Due to their ubiquity and recurrent geographical patterns, selected biological tags can be considered as useful tools for management procedures such as multispecies fisheries. Their potential application goes from providing theoretical frames for generating hypothesis about stock structure to tracing fish migrations across ecosystems, and identifying the origins of catches for given species, even when their parasite fauna could be unknown in other regions. The identification of ecosystem markers can also provide essential information to delineate ecosystem boundaries for host communities whose components differ considerably in their temporal and spatial population dynamics. This new concept and its application could be a powerful tool to help the implementation of ecosystembased approaches to fisheries management, the new paradigm for fisheries science, on which regional fisheries are focusing.