Indiseas - Ecosystem Full Description

STATUS OF MARINE ECOSYSTEMS

To view an ecosystem and a evaluation of its state, click on the corresponding location in the world map or consult the list below.

COMPARATIVE APPROACH

Select and compare the states and trends of several ecosystems (pie diagrams and time series)

ABOUT indiSeas

Methods details

About us

FRANÇAIS
ESPAÑOL
ENGLISH

to the map

to the ecosystem

South Brazil Bight

Overview of the ecosystem and its fisheries

Geographic Area

The South Brazil Bight (SBB) is a crescent shaped located between 23ºS 41’W and 28º S 48’W, at the northern end of the South Brazil Large Marine Ecosystem (SBLME, Fig. 1). The SBB was considered a proper biogeographic unit and has also been called the Santos Basin. The areal extent of the SBB to the 200 m depth contour is 136, 585 km2, and to the 1000 m depth is around 169,500 km².

FAO Fishing Areas: [ 41.2.1 ]

Environment

Oceanographically, the South Brazil Bight is characterized by isobaths that run almost parallel to the coastline, the occurrence of meso-scale eddies from the Brazil Current (to the east), and two seasonal features that boost primary productivity in the ecosystem, the South Atlantic Central Water (SACW) intrusion and Cabo Frio upwellings. In the inner shelf, major oceanographic interactions occur among warm, saline, oligotrophic surface water (the so-called Tropical Water), low saline, productive Coastal Water highly influenced by river runoff and the seasonal wind-driven penetration of cold, nutrient-rich slope water (SACW) towards the coast. During the winter, the cold, low-salinity water from the La Plata River plume often influences the southern portion of the bight, through waters originating from the Malvinas current/Subtropical Convergence.

Ecology

The intrusion of wind-driven cold nutrient-rich waters is an important process enhancing system productivity and favoring the recruitment of small pelagic fish species, such as the Brazilian sardine Sardinella brasiliensis and loliginid squid. The Brazilian sardine stock sustains one of Brazil’s most important fisheries. Loliginid squid (Doryteuthis plei) are thought to play a key ecological role in the ecosystem as predators and prey, linking the pelagic and benthic sub-systems (Gasalla et al., 2010b). Sciaenids (e.g. Micropogonias furnieri, Cynoscion guatucupa, Cynoscion jamaicensis, Macrodon ancylodon) are the most abundant demersal fish species in the shelf, followed by Trichiurus lepturus, Merluccius hubbsi and rays. Other important species in coastal and estuarine zones are the mullets Mugil platanus and M. curema, and in deeper waters around 500 m, the monkfish (Lophius gastrophysus). Generally, demersal fauna is more abundant in depths less than 50 m than at greater depths further offshore, and decapod crustaceans are important prey items for benthic fish species.

One of the most important large pelagic fish species is the skipjack tuna, Katsuwonus pelamis, generally associated with the western margin of the subtropical convergence. They migrate northward when cold waters from the Malvinas current reaches the slope and shelf. They consume mainly neritic (coastal) and epipelagic (oceanic pelagic – 0 to 200 m) fish and mesopelagic (oceanic pelagic – 200 to 700 m) squid and the small pelagic lanternfish Maurolicus muelleri, which is an important base of the foodweb as forage species.

Exploitation

Total landings in the South Brazil LME increased during the 1970s, peaking at 350,000 mt in 1985, but have decreased since then to about 124,000 mt. The South Brazil Bight contributes about half of Brazil’s commercial fisheries yield and supports important pelagic and demersal fisheries. Some stocks of the SSB has been declining and over-exploitation has been associated with high fishing effort levels, promoted by Government fishing incentive policies such as tax deductions for investment in fishing ventures and fuel, especially in the 1970s, (Valentini and Pezzuto, 2006; Abdallah and Sumaila, 2007). Bottom trawling across the relatively smooth, sandy-mud bottom was the main type of fishing activity. The main demersal stocks exploited in the region were the white-mouth croaker Micropogonias furnieri, king weakfish Macrodon ancylodon, weakfish Cynoscion jamaiscencis, triggerfish Balistes capriscus and the marine shrimps Xiphopenaeus kroyeri (seabob shrimp), Farfantepenaeus brasiliensis and F. paulensis (pink-shrimp). Moreover, the presence of small pelagic stocks (particularly sardines) led to the development of an important purse-seine fishery, especially since 1950. The sardine fishery catch dropped from 228,000 mt in 1973 to 17,000 mt in 2000, while the pink-shrimp trawl fishery declined from 16,629 mt in 1972 to 1,166 mt in 2001. Conversely, the pole-and-line based fishery for skipjack tuna (Katsuwonus pelamis) increased during the 1980s as a consequence of the regional expansion of industrial fisheries offshore. Other fleets that operated in this region included longliners in oceanic zones and gillnetters in the shelf area. Overall, most fishing vessel operates in the shelf’s region, and those fisheries are presently multispecies/opportunists.

Ecosystem Approach to Fisheries

EAF has not been well defined or applied in Brazil’s national fishery management system. However, some scientific research projects have included EAF objectives. Several issues have been identified by means of dedicated projects that included ecosystem-based studies and by others that produced innovative methods oriented to support EAF management. Trophic models of structural and functional properties of the ecosystem have been an important advance. Multispecies/multifleet analysis at the ecosystem scale have been also attempted. The estimates of fisheries socio-economic indicators as proposed by Gasalla et al (2010a) for incorporation in ecosystem models and management showed a fishing fleet’ costs analysis in an EAF perspective, providing practical advice to rational decision-making. Also, a seafood market analysis using multispecies indicators were shown in Pincinato and Gasalla (2010) which also incorporated econometrics proved to be relevant to the understanding of the ecosystem’s history and over-exploitation trends. Some studies combining ecosystem effects of fishing and the environmental impact on fishing stocks have been applied, e.g. for squids (Postuma and Gasalla, 2010). In terms of the assessment of traditional knowledge in a particular EAF perspective, Leite and Gasalla (2010) and Gasalla and Diegues (2011) showed some innovative approaches. Concerning community-based perspectives for an EAF, Gasalla (2011) discussed the issue of fishing rights in marine conservation and ecosystem-based fishery management.

Data Sources

Information was provided by the Fisheries Ecosystem Laboratory (LabPesq), Oceanographic Institute, University of São Paulo, in São Paulo, Brazil.

Regional fisheries landings data sources: