Trophic ecology of Mugil liza in the southern limit of its distribution (Buenos Aires, Argentina)

THOMPSON, GUSTAVO; CALLICO ROBERTA; CHIESA IGNACIO; VOLPEDO, ALEJANDRA

BRAZILIAN JOURNAL OF OCEANOGRAPHY

INST OCEANOGRAFICO

Lugar: São Paulo; Año: 2015 vol. 63 p. 271 - 278

1679-8759

ABSTRACT: In order to get knowing of the ecological habitat and feeding habits of Mugil liza on the southern coast of Buenos Aires, 65 specimens obtained during spring (November 2012) and summer (February 2013) were analyzed at two sampling sites: San Blas bay (SBB) and mouth area of the Quequén-Salado river (QSR). Specimens were measured, sexed, weighed, stomach was removed and stomach contents weighed and analyzed under stereoscopic microscope. Specimens were adults with sizes 28-49 cm and weights 380-1100 g. Population growth was higher in SBB (TW: 0.003*TL3.36), than in RQS (TW: 0.045*TL2.61). About 98% of the stomachs had stomach contents and repletion rate was between 0.4 and 1.2%. About 75% of stomach contents was composed of very fine sand with little presence of benthic organisms (algae, copepods, foraminifera), while stomachs with coarse sand and increased presence of benthic fauna were found in the remaining 25% (amphipods, bivalves, gastropods and coral organisms). Linear relationship between the weight of stomach contents and the total weight and length of the fish showed that the rates of growth (slope) were the same in both sites, but intercept values were significantly higher for San Blas bay (test parallelism; p < 0.001).