CONTRIBUTION OF POLYCHAETOUS ANNELIDS TO THE DIET OF CHEILODACTYLUS BERGI (PISCES, CHEILODACTYLIDAE).
Bruno, C. 1 ; Cousseau, M. B.1 & Bremec, C. 2
1 Departamento de Ciencias Marinas, Universidad Nacional de Mar del Plata. Dean Funes 3350 (7600) Mar del Plata, Argentina.
2 CONICET- Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP). (7600) Mar del Plata, Argentina.
The hawkfish (castañeta) Cheilodactylus bergi Norman, 1937 is distributed in the Atlantic Ocean, from southern Brazil (22ºS) to San Jorge Gulf in Argentina (47ºS), between 50 and 150m depth, and constitutes a fishing resource of potential interest. Previous studies indicate that Annelida Polychaeta constitute the main food items for this species. The contribution of different families of worms to the diet of hawkfish, and the relationships between those taxa and the benthic fauna of the feeding grounds are presented in this paper. Altogether 522 specimens were measured, weighted and the gut contents were analysed. Polychaete families, mainly Onuphidae, Lumbrineridae and Eunicidae, were the most important feeding items in hawkfish from 28 to 51cm total length, both in percentage of frequence (%F) and percentage of weight (%W). Occasional presences of Aphroditidae, Arabellidae, Palmyridae, Lysaretidae and Dorvilleidae were recorded. Bibliographic data on faunistic composition of feeding grounds indicate that polychaetes contribute between 12% to 21% of the number of taxa in the benthic assemblages of invertebrates. Polychaetes consumed by C. bergi are between 25% to 38% of the total possible range of annelid taxa. It is concluded that polychaetes are predated according to their habits. It is mainly the mobile and jawed species, with feeding habits that imply some mobility over the bottom, that constitute available prey to C. bergi.