Demersal bony fish of the outer shelf and upper slope of the southern Brazil Subtropical Convergence Ecosystem

Abstract

ABSTRACT. Ninety-three species of bony fishes were caught in 4 seasonal bottom-trawl surveys carried out between July 1986 and May 1987 on the outer shelf and upper slope (124 to 587 m depth) along the southern Brazilian coast (30°40' to 34"30' S). On the outer shelf (< 179 m), the demersalpelagic species Trichiurus lepturus, Trachurus lathami, Cynoscion guatucupa, Scomber japonicus, and Thyrsitops lepidopoides predominated and also to a lesser degree the demersal benthonic Umbrina canosai and Mullus argentinae. Antiyonia capros and Priacanthus arenatus were found associated with the relic coral hard bottoms of the shelf break (180 to 249 m). Further offshore, the demersal-pelagic species Ariomma bondi and Zenopsis conchifera and the demersal benthonic species Polyprion americanus and Helicolenus lahillei were abundant, both associated with rocky bottoms. The macrourids Coelorinchus marinii and Malacocephalus occidentalis characterized deep-water hauls p 4 5 0 m). Frequent and widespread, but less abundant in the catch, were Polymixia lowei, Urophycis mystacea and Merluccius hubbsi. Mean total catch (kg h-') decreased 6-fold and the number of species by more than half along the depth range, with a sharp step at 350 m. Both catch and number of species were slightly higher in the winter cruises. Most species occurred in both winter and summer-autumn cruises, but, with increasing depth, the relative abundance of species that occur year-round decreased, whereas fishes that occur mostly in winter increased. The catch of demersal-pelagic fish decreased sharply below 350 m and differed little among seasons; catches of demersal-benthonic fish were more evenly distributed across the depth range and were larger in winter and spring. The high number of species on the shelf break may be attributable to the higher variety of soft and consolidated substrates and the overlapping of different water masses along the water column. The north-south shift of the western boundary of the Subtropical Convergence appears to be mainly responsible for the seasonal changes in abundance of the species.

Stomach contents and notes on the reproduction of the Onefin Skate Gurgesiella dorsalifera (Chondrichthyes: Rajidae) off Southern Brazil

“…Adults of U. brasiliensis are not common in deep waters of 400 to 600 meters (Haimovici et al, 1994), but the high importance of these juveniles in the stomachs is strong evidence that it could be a nursery area for U. brasiliensis. Comyns & Grant (1992) have observed indications of a shoreward migration for recruitment of U. tenuis in the U.S Middle Atlantic Bight and larger concentrations of U. brasiliensis larvae have also been observed on offshore to oceanic waters of Southern Brazil (José Muelbert pers.…”

Fish, Sternoptychidae, Maurolicus stehmanni Parin &amp; Kobyliansky, 1993: occurrence and distribution in south and southeastern Brazilian waters

“…The species of Maurolicus are an important component of the food chain in deep waters, preying on zooplankton and being the most common prey for large predators, such as tuna and squids (Boehlert et al 1994;Rasmussen and Giske 1994;Parin and Kobyliansky 1996;Muto et al 2005). Its importance for the diet of fish with commercial value in Brazilian waters was noted by ZavalaCamin (1981), Haimovici et al (1994), Ribeiro (1996), and recently by Muto et al (2005) and Gasalla et al (2007).…”

“…The studies on Maurolicus in Brazilian waters have always referred to the species as Maurolicus muelleri (Zavala-Camin 1981;Weiss et al 1988;Bonecker and Hubold 1990;Haimovici et al 1994;Ribeiro 1996;Greig 2000), although the revision of the genus by Parin and Kobyliansky (1993;1996) distinguishes a new species in the Southwest Atlantic (between 34° and 40° S), named Maurolicus stehmanni.…”

Diet and feeding strategy of the dusky grouper Mycteroperca marginata (Actinopterygii: Epinephelidae) in a man-made rocky habitat in southern Brazil

“…In southern Brazil, M. marginata is exploited by fishermen in rocky bottoms along the coastline (Haimovici et al, 1994). The rocky substrates of the MBRG harbors a population of dusky groupers that has been regularly exploited by sport and commercial fisheries and represents a significant source of income to local artisanal fishermen (Condini et al, 2007).…”

“…In the Rio Grande do Sul, the southernmost State of Brazil, the current knowledge regarding the dusky grouper is basically restricted to fishery aspects (Haimovici et al, 1994;Condini et al, 2007) and no prior ecological research have been done with this endangered species in this region. The main goal of the current study was to investigate diet composition, feeding strategy and size related dietary shifts of a dusky grouper population inhabiting the MBRG, which was originally built in the beginning of the twentieth-century to maintain a navigation channel between a large subtropical coastal lagoon and the sea.…”