Patterns of habitat use by fish in Spartina densiflora saltmarsh related areas (Argentina).

VALIÑAS, M.S.; IRIBARNE, O.O; ACHA, E.M.

Bahía Blanca, Argentina

Simposio; ECSA 44 Symposium: Science and management of estuaries and coasts: A tale of two hemispheres.; 2008

ECSA- IADO (CONICET)

Organisms potentially respond to a variety of factors when selecting habitats. Salt marshes are ecotones that are used by numerous organisms like refuge, reproduction, nursery or feeding areas. This study examine fish use of marsh channel and tidal flat in Spartina densiflora saltmarshes at Mar Chiquita Coastal lagoon (Argentina). During two springs and two summers fish samples were taken in both areas. To evaluate prey availability for bentivorous fishes, infaunal abundance of organisms were evaluated. Six species was collected in marsh channel and eight in tidal flat. The most abundant fishes were Odontesthes argentinensis, Micropogonias furnieri and Brevoortia aurea. Only O. argentinensis and B. aurea were collected in all seasons. No difference in B. aurea abundance was found between areas. O. argentinensis abundance was higher in tidal flat in summer 2006. M. furnieri was collected in summer seasons. Higher abundance was found in tidal channel in summer 2006. Polychaetes abundance was high in marsh channel in summer 2006 and in tidal flat in summer 2007. The others infaunal organisms were more abundant in marsh channel in both years. Polychaetes are one of the most important prey items for bentivorous fish diet (pers. obs.). O. argentinensis higher abundance not coincided with higher polychaetes abundance, nevertheless higher abundance of M. furnieri coincided with higher abundance of polychaetes in tidal flat. These results suggest that M. furnieri could be use tidal flat specifically as feeding areas. This work shows the importance of Spartina densiflora related areas for different fish species.