The relationship between environmental variation and species abundance in shrimp community (Crustacea: Decapoda: Penaeoidea) in south-eastern Brazil

Abstract

The impact of shrimp fisheries in tropical regions has become comparable to the world's most intensively exploited temperate shelf ecosystems. The increase in the fishing fleet in south-eastern Brazil and the decrease in landings of profitable shrimp species have contributed to the incorporation of additional species into those fisheries. The goal of the present study is to investigate the influence of environmental factors on the abundance patterns of shrimp communities on the south-eastern coast of Brazil, over a period of two years. Monthly collections were conducted in the Ubatuba and Caraguatatuba regions using a commercial shrimp fishing boat equipped with 'double-rig' nets. Each region was divided into 7 sampling stations up to 35 m deep. The relationship between the environmental factors and the abundance patterns in the shrimp communities was assessed using a canonical correlation analysis (CCorrA). The first set of variables used during the CCorrA included environmental characteristics and the second set of variables the abundance of the studied species. A total of 374,915 individuals were collected during the present study. Xiphopenaeus kroyeri showed the highest abundance (273,127), followed by Artemesia longinaris (73,422), and Pleoticus muelleri (15,262). In the first root, depth and temperature showed the highest factor loadings (0.9 and 20.7) and canonical weights (0.6 and 20.4). These environmental factors were strongly associated with the abundance of X. kroyeri (factor loading ¼ 2 0.9 and canonical weight ¼ 2 0.9). The second root demonstrated a positive relationship between abundance of P. muelleri and depth, and an inverse association with bottom temperature. The abundance patterns of X. kroyeri and P. muelleri were strongly affected by the water mass South Atlantic Central Water (cold waters ¼158C), which can lead to a temperature decrease in deeper areas (.15 m). Thus, the opposite abundance trend for depth of these species might reflect bathymetric variation in temperature, a clear example of distinct behavioural differences of species of different origins, either tropical (X. kroyeri) or subantarctic (P. muelleri). The low overall association between environmental parameters and shrimp abundance patterns indicates that each studied species might have responded idiosyncratically to environmental variation, such that a general community-level response was not apparent. However, other confounding factors such as intraspecific migration patterns might have also played a role in generating the observed patterns.

Feeding habits of the congeneric species Stellifer rastrifer and Stellifer brasiliensis (Acanthopterygii: Sciaenidae) co-occurring in the coast of the state of Santa Catarina, Brazil

“…A similar result was found by Rodrigues and Meira (1988), with the presence of the seabob shrimp in only 22 of the 77 analyzed stomachs of S. rastrifer and 2 of the 36 analyzed stomachs of S. basiliensis. It is known that penaeid shrimps are benthic and burry themselves in the sediment (Castilho et al, 2008;Simões et al, 2012), and therefore are available in a smaller scale for benthopelagic consumers, such as S. rastrifer and S. brasiliensis (Wakabara et al, 1993). Even if juveniles of X. kroyeri, are available in the pelagic zones for these fishes, they may be choosing to consume shrimp from the genus Acetes not only for their abundance in the studied environment, but for their short and blunt rostrum, that are of easier consumption than the sea-bob's rostrum with five teeth near the base and slightly curved upwards.…”

Annual, seasonal and spatial abundance of the seabob shrimp Xiphopenaeus kroyeri (Decapoda, Penaeidae) off the Southeastern coast of Brazil

“…Since X. kroyeri has benthic habits, the availability of sediment types is important for their distribution (Costa et al 2007, Castilho et al 2008b once it provides protection against predators and minimizes energy cost when buried (Ameeri andCruz 1998, Simões et al 2010). Sediment of all sampling locations of the bay showed predominance of very fine sand.…”

“…Previous studies on X. kroyeri populations of the northern coast of the state of São Paulo concluded that high temperature, salinity and very fine sand influenced the distribution of this species (Fransozo et al 2002, Costa et al 2007, Castilho et al 2008b. A relevant complementation for these findings would be a more detailed analysis of these populations involving demographic categories, since marine shrimps establish in areas with different environmental characteristics, according to their life stage (Dall et al 1990).…”

Diel Variation in Abundance and Size of the South American Red Shrimp Pleoticus Muelleri (Spence Bate, 1888) (Decapoda, Solenoceridae) in the Ubatuba Region, Southeastern Brazil

“…Its life cycle is exclusively marine. Higher biomasses are found in salinities above 30 and at temperatures below 20°C (COSTA et al, 2004;MALLO, 2005;CASTILHO et al, 2008a).…”

“…Information on the biology of this species has also been obtained from the southeastern coast of Brazil, specifically from the state of São Paulo, including reports on the species' ecological distribution (COSTA et al, 2004), its reproductive biology (CASTILHO et al, 2008a) and the relationship between environmental variation and species abundance in the shrimp community (CASTILHO et al, 2008b). However, no studies on the variation between day and night in the catch and size of the South American red shrimp have yet been undertaken in any part of the area of its geographical distribution.…”