Geographical variation and local environment effects in the reproductive output and fecundity of the shrimpExhippolysmata oplophoroides(Decapoda: Caridea) in southeastern Brazil

Abstract

We studied the shrimp Exhippolysmata oplophoroides in southeastern Brazil (Macaé, 22º37″S; Ubatuba, 23º55″S; and Cananéia, 25º53″S) to test the hypotheses that (1) females should have the same reproductive output and fecundity at the regional scale, and (2) these reproductive parameters can vary among regions. Maximum carapace length (Macaé = 13.1 mm, Ubatuba = 12.8, Cananéia = 16), fecundity, and reproductive output differed among regions (Ancova, p < 0.05). Females in Cananéia exhibited the highest reproductive output/fecundity (18.6%/5230 embryos), followed by those in Macaé (16.0%/4365 embryos) and Ubatuba (12.6%/1206 embryos). We found that fecundity/reproductive output varies inversely with the length of the reproductive season, i.e. a considerable amount of energy is allocated during seasonal spawning periods in subtropical regions such as Cananéia. Previous studies have proved that E. oplophoroides is able to reproduce continuously in Ubatuba, with probably minor but continuous energy investment in reproduction occurring in this tropical region. In contrast, although Macaé is located at tropical latitude, it is under the influence of Cabo Frio upwelling that alters the water's physical properties via cold water intrusion. This process may be a determining factor in the spawning seasonality of Macaé's shrimp population, justifying the higher reproductive output recorded here than in Ubatuba.

Decapod abundance and species richness in the bycatch of Xiphopenaeus kroyeri (Heller, 1862) fishery, Santa Catarina, southern Brazil

“…Additionally, the presence of a considerable number of species classified as Co makes this region highly ecologically important. These data suggest that this heterogeneous environment provides a variety of microhabitats and corresponding environmental complexity (Garcia et al, 2018). Thus, fishing activities in this region may present a risk to the local fauna, either from bycatch or from the seafloor alterations that the trawling fleet may cause (Pilskaln et al, 1998;Beserra da Silva Júnior et al, 2015).…”

“…Trawling fisheries might also impact the accessory and accidentally collected species, primarily because these species have higher occurrences in the spring and summer, which are seasons known for having high primary productivity (Stanski et al, 2018). Marine decapod crustaceans exhibit migratory tendencies toward regions with higher food availability in order to reproduce, since, during their early developmental stages, the offspring will find abundant food resources to grow and develop properly.…”