. Parasite assemblages in volatile host stocks: inter- and intra-cohort variability restrict their value as biological tags for squid stock assessment

GUTIERREZ M.P.; CANEL D.; BRAICOVICH P.E.; LANFRANCHI A.L.; IRIGOITIA M.M.; IVANOVIC M.; PRANDONI N.; ELENA B.; TIMI J.T.

PARASITOLOGY

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2023 p. 1254 - 1262

0031-1820

The Argentine shortfin squid, Illex argentinus, inhabits in the southwest Atlantic; it is a semelparous species which grows rapidly along its 1 year lifespan. The identification of its stocks iscritical for sustainable fishery exploitation. Parasites have been used as biological indicators ina lower number of studies dealing with squids, therefore a validation of this methodology isnecessary. The intra- and inter-cohort variability of parasite assemblages in the summerspawning stock of I. argentinus was analysed to assess their value as indicators of stock structure. Four squid samples from the continental shelf of central Patagonia, corresponding to 3consecutive cohorts, were examined for metazoan parasites. Results evidenced heterogeneityin terms of parasite assemblage composition and structure, dominated by short-lived gastrointestinal parasites, with a strong influence of host size, but no effect of squid sex. Thesechanges are related to their recent habitats and diets, which change with ontogeny and migrations, clouding any interpretation of patterns when samples spatially or temporally separatedare compared. Many squid species share these characteristics; therefore, it is recommendedthat the use of parasites as biological tags should be restricted to simultaneous sampling,while size or age must be considered for deriving proper conclusions.