Microhabitat preferences of the freshwater prawn Macrobrachium jelskii (Decapoda: Palaemonidae)

Abstract

We analyzed the microhabitat preferences of Macrobrachium jelskii (Miers, 1877) males and females inhabiting an urban water reservoir in Cruz das Almas, Bahia, Brazil. Prawns were collected monthly, from March 2015 to February 2016, in three microhabitats, using a sieve. Each microhabitat was dominated by one macrophyte species: Eleocharis sp. (M1), Cabomba sp. (M2), and Nymphaea sp. (M3). The prawns were measured (carapace length), and categorized as juvenile males, adult males, juvenile females, non-ovigerous adult females and ovigerous adult females. An analysis of variance (ANOVA) was used to compare the number and size of individuals. The sex ratio and frequency of ovigerous females in the three microhabitats were also calculated. The sex ratio was biased towards females in M1 and did not deviate from 1:1 in M2 and M3. When prawns were separated into five categories we observed that non-ovigerous adult females were more abundant in M1, while adult males were the most abundant demographic category in M2 and M3. Juveniles of both sexes and ovigerous females showed no microhabitat preference, although M1 and M2 appeared to be more suitable for the latter. Adult females were the largest individuals in all microhabitats. Food availability, lower depth and lower predation pressure in M1 are the main factors that make M1 more suitable for M. jelskii, particularly non-ovigerous adult females and larger adult males. Intraspecific competition for shelter in M1 might also occur and adult females win this competition due to their larger body size. Therefore, adult males are found in higher abundance in M2 and M3 and the juvenile of both sexes spread evenly across all microhabitats. Our results help to understand the ecological role and the niche used by M. jelskii. Future studies on the habitat choice and predation under laboratory conditions should help to understand the behavior of this species.

Population structure and fecundity of Macrobrachium jelskii (Miers, 1877) (Decapoda, Palaemonidae) on the Batateiras River, sub-basin of the Salgado River, in southern Ceará, Brazil

“…The sexual size dimorphism found in the present study, where females are morphometrically larger than males, is widely known for M. jelskii (Barros-Alves et al, 2012;Rocha and Barbosa, 2017;Taddei et al, 2017a;Silva et al, 2019a;Nascimento et al, 2020). This pattern can be explained by the evolution of reproductive strategies for M. jeslkii.…”

“…In M. jelskii, Barros-Alves et al (2012) observed a sex ratio of 1M:1.48F in Minas Gerais, Brazil; Rocha and Barbosa (2017) and Silva et al (2019a) in separate populations from Bahia, Brazil, observed a sex ratio of 1M:1.4F and 1M:1.04F, respectively; and Mossolin et al (2013) also observed the female biased sex ratio (1M:1.08F) in São Paulo, Brazil, but without statistical significance. Soares et al (2015) observed a biased proportion for females (1M:1.76F) upstream of the Três Marias Dam, Minas Gerais, Brazil, however, the sex ratio downstream was 1M:0.75F.…”

Salinity tolerance and water ionic balance in Macrobrachium jelskii post-larvae

“…It is a small species (Taddei et al 2017), with low fertility (Nery et al 2015), but with abbreviated larval development (Rocha et al 2016) and which facilitates its adaptation to freshwater environments. The species has a preference for densely vegetated places (Silva et al 2019), present in inland and estuarine regions (Lucena et al 2020;Macedo 2021), with potential for aquaculture production (Soares 2008;Urbano et al 2010), and resistance to contaminated environments by human pollution (Mota et al 2021).…”