Influence of environmental factors on the bathymetric distribution of the flecked box crab Hepatus pudibundus (Herbst, 1785) (Crustacea: Aethroidea) in the Southeastern Brazilian coast

Abstract

This study evaluated the relationships between environmental factors and the spatio-temporal distribution of H. pudibundus, with the hypothesis of differential occupation in coastal areas of southeastern Brazil. The samplings took place monthly in January-December 2000 period, along nine transects from 2 to 40 m of depth, in Ubatuba region, northern coast of São Paulo. We collected 1808 individuals of H. pudibundus. The highest abundance was recorded in winter in the transects 10-25 m deep. Abundance was positively correlated with organic matter content and texture sediment (phi values). With the retreat of the South Atlantic Central Water (SACW) in autumn and winter, the sediment swirls, suspending the detritivore and filter-feeding macrofauna, increasing the food availability. Sites characterized by finer sediment offer higher food availability, besides facilitating H. pudibundus burying behavior. Due to its opportunistic predatory behavior, this species feeds on a variety of organisms, including mollusks, annelids and foraminifera, which are preys more abundant in the studied area and in sediments of finer grain size.

Assessing the factors driving the changes in the spatio‐temporal distribution of Hepatus pudibundus (Decapoda, Brachyura) over a 20‐year interval in a region under the influence of El Niño (ENSO)

“…According to the CA, the distribution of males and females was similar in both periods and were associated with spring and summer. This pattern is common for H. pudibundus and has already been recorded in Ubatuba by and Bernardes et al (2019), and in other regions on the Brazilian coast, for example, in Cananéia (São Paulo) by Miazaki (2017), in Balneário Camboriú (Santa Catarina) by Sardá et al (2013). The spring and beginning of summer are the periods that most favor the occurrence of several decapod crustacean species in Ubatuba due to the entrance of the SACW to 20 m deep (Fransozo et al, 2016;Pires-Vanin, 1993).…”

“…(2014) and Bernardes et al. (2019), and in other regions on the Brazilian coast, for example, in Cananéia (São Paulo) by Miazaki (2017), in Balneário Camboriú (Santa Catarina) by Sardá et al. (2013).…”

Bathymetric distribution of brachyuran crabs: Alpha and beta diversity variation in an upwelling area

“…The SACW intensifies the Cabo Frio upwelling (Stech & Lorenzzetti, 1992) since its physical and chemical features increase nutrient production that favors primary production (Castro-Filho et al, 1987 Coefficients greater than or equal to +0.4, or lower than or equal to −0.4 were considered ecologically relevant (Rakocinski et al, 1996) and are presented in the plot. BT, bottom temperature; OM, organic matter percentage; H', diversity; J', evenness; S', richness above 21°C (Bernardes et al, 2019;Petti et al, 1996;Pires-Vanin & Matsuura, 1993). Therefore, environmental conditions caused by the upwelling more intensely affect species that are adapted to temperatures close to 20°C or lower, such as A. spinicarpus (De Léo & Pires-Vanin, 2006), decreasing the diversity index during the phenomenon.…”

“…Several studies have demonstrated that low temperatures modulate the occurrence of Brachyura species during spring and summer in Macaé, and on the coast of the state of São Paulo (Bernardes et al, 2019;Costa et al, 2016;Sousa et al, 2018).…”

“…Bertini et al (2010) andBernardes et al (2019) have also associated the higher abundance of H. pudibundus with small sediment grain size in Ubatuba, such as silt and clay.The establishment of A. spinicarpus in the deep area was associated with temperature. The species has a distribution pattern associated with temperatures below 18°C, being an indicator of cold water F I G U R E 6 Spatial and temporal abundance of the most abundant species.…”