Reproductive biology of Neohelice granulata (Decapoda: Varunidae) in two salt marshes of the estuarine region of the Lagoa dos Patos Lagoon, southern Brazil

Abstract

Neohelice granulata is a crab found in salt marshes and mangroves of the south and south-eastern Atlantic coast of South America. Reproductive biology was studied by taking samples for two years at two salt marshes—‘Prainha’ and ‘Ilha’—in the estuarine region of Patos Lagoon (southern Brazil). Ovigerous females were found most of the year in both salt marshes with average CW ranging from 18.5 (Prainha) to 22.8 mm (Ilha). A significant linear relationship was found between log(CW) and log(number of eggs). Average size at the onset of maturation was 14.9 and 14 mm at Prainha, for males and females, respectively, while at Ilha it was 18.2 and 16.8 mm, for males and females, respectively. Results provided evidence of significant differences in reproductive traits between populations of the two salt marshes. Differences are likely related to the higher organic matter content found in the sediment from Ilha.

Effects of seasonality and moult cycle on the proliferation of nerve cells and on the labelling of ecdysone receptors in an estuarine crab

“…= 18.6 ± 1.0 mm) and in winter (17.8 ± 1.0 mm). However, the difference found was the opposite of that expected, as many physiological processes are enhanced in the higher temperatures in spring/summer, and Neohelice granulata clearly shows more intense growth and reproduction in spring/summer (Bas et al 2009;Barutot et al 2009). At this stage, any explanation for the observed higher proliferation rate in winter is merely speculative, but this first evidence of a difference between seasons cannot be ignored.…”

“…Males and females allocate most of their energy to the reproductive process, and assuming a finite pool of energetic resources, a trade-off is required between allocation to reproduction and allocation to somatic maintenance (Calow 1983). N. granulata typically reproduces in spring and summer (Barutot et al 2009). Therefore, during winter, crabs probably have more energy to expend on other processes, such as proliferation.…”

“…The result is that growth and reproduction in decapods inhabiting subtropical regions are typically seasonal, as in summer these processes are more intense. For Neohelice granulata, a common salt-marsh crab in the Patos Lagoon estuary, the effects of seasonality on growth and reproduction have been characterised (Bas et al 2009;Barutot et al 2009). This species is active in summer, and in winter it remains longer in the burrows and its metabolic rate slows down (D'Incao et al 1993;Monserrat and Bianchini 1995).…”

Fecundity Variation and Abundance of Female Blue Crabs Callinectes Sapidus Rathbun, 1896 (Decapoda, Brachyura, Portunidae) in the Patos Lagoon Estuary, Rs, Brazil

“…The fecundity of Callinectes sapidus in the Patos Lagoon estuary is similar to other inhabited estuaries (Table IV). Methods of obtaining fecundity varied through time (Diaz, 1983, Barutot et al, 2009, possibly explaining some of the differences in fecundity estimates obtained for C. sapidus in other studies. It is clear that among the species that occur in the Patos Lagoon estuary, C. sapidus produces the most eggs.…”

“…the eggs were preserved in ethanol 70%, losing most of their water content, and therefore were not considered accurate measurements of egg diameter. There is great variation in fecundity among Brachyura: the grapsoid crab Neohelice granulata (Dana, 1851) can carry an average of 28.000 eggs (Barutot et al, 2009) while some majids have highly variable fecundity, ranging from 4 to 180 million eggs per female (Schejter & Spivak, 2005). A species that relies on a large number of eggs tends to use a reproductive strategy (r) rather than parental care (K).…”