Fish composition in a south-western Atlantic temperate coastal lagoon: spatial–temporal variation and relationships with environmental variables

Abstract

Mar Chiquita, an irregularly shaped brackish-water coastal lagoon, is located in the Buenos Aires province of Argentina and considered since 1996 by the Coordination Council of the Man and Biosphere Program of UNESCO as a World Reserve of Biosphere. The present paper aims to study both the spatial and temporal variation of fish composition in this coastal lagoon and the influence of some environmental variables on the relative abundance of the main fish species. Monthly sampling surveys over a two-year period in three different areas were conducted, using a beach-seine net and three monofilament-gill nets with different mesh size. Twenty-eight species belonging to four bio-ecological categories were identified, five of them are new records for Mar Chiquita fish community. The correspondence analysis showed strong relationships between high salinity range and the abundance of Brevoortia aurea, Cynoscion guatucupa and Pomatomus saltatrix. Conversely, low salinity range corresponded to high abundance of Mugil platanus and Odontesthes argentinensis. High temperatures were corresponded with abundance of Micropogonias furnieri and Brevoortia aurea. In contrast, high abundance of both Odontesthes argentinensis and Oligosarcus jenynsii were corresponded to low temperatures. Brevoortia aurea, Mugil platanus and Odontesthes argentinensis were the most abundant species, representing more than 80% of the total capture. The group of estuarine-nondependent-marine fish presented the highest species richness. Estuarine-dependent-marine species presented for both juveniles and adults specimens the highest abundance values.

Reproduction of Brevoortia aurea (Spix & Agassiz, 1829) (Actinopterygii: Clupeidae) in the Mar Chiquita Coastal Lagoon, Buenos Aires, Argentina

“…Conversely, the lowest temperatures were correlated with the lowest abundances of B. aurea recorded for the present paper. Moreover, González-Castro et al (2009a) found no records of adults specimens of B. aurea in the inner zone of Mar Chiquita coastal Lagoon: this data support the results of the present paper (no records of adult specimens in winter in the inlet channel of the lagoon have been found), suggesting that adult specimens migrate from the lagoon to the sea (between June to August) when the water temperature decreases below the physiological tolerance level of the species. Similar results have been observed by Lopez-Cazorla (1985) for the estuary of Bahía Blanca, Argentina, where adult specimens enter the bay in spring to reproduce and migrate offshore at the end of summer.…”

“…Moreover, the authors found high densities of early juveniles in summer and autumn. Furhermore, Bruno et al (2013) reported high density of eggs and larvae of B. aurea, in Zone I (sensu González-Castro et al, 2009a), which basically is the sample site of the present study. Here, B. aurea was collected in Mar Chiquita lagoon almost every month (with the exception of June, July and August).…”

“…Fish composition of Mar Chiquita coastal lagoon has been recently analysed (González-Castro et al, 2009a). The authors recorded the presence of high densities of B. aurea in spring/summer correlated with mature/ripe ovaries, as was revealed by sexual maturity stage analysis performed at macroscopic level.…”

“…From a total of 28 reported fish species, B. aurea represented the most abundant species in Mar Chiquita coastal lagoon (González-Castro et al, 2009a). High densities of B. aurea specimens in the inner zone of Mar Chiquita lagoon were correlated with mature/ripe ovaries, as revealed by sexual maturity stage analysis.…”

“…Brevoortia aurea is an estuarine-dependent, pelagic, coastal species, inhabiting shallow nursery areas for their early development, which is capable to perform migrations between the sea and estuaries (Cousseau & Díaz de Astarloa, 1993;González-Castro et al, 2009a;Cousseau et al, 2011). As a filter feeder, the species has a key position between the primary producers and the secondary consumers on the trophic chain.…”