Journal of Crustacean Biology Advance Access published 23 November 2018 Journal of Crustacean Biology The Crustacean Society Journal of Crustacean Biology 39(1) 74–81, 2019. doi:10.1093/jcbiol/ruy087 Reproductive potential of Ucides cordatus (Linnaeus, 1763) (Decapoda: Brachyura: Ocypodidae) from two mangrove areas subject to different levels of Downloaded from https://academic.oup.com/jcb/article-abstract/39/1/74/5202066 by guest on 26 May 2020 contaminants Marcio C.A. João and Marcelo A.A. Pinheiro Universidade Estadual Paulista (UNESP), Instituto de Biociências (IB), Campus do Litoral Paulista (CLP), Grupo de Pesquisa em Biologia de Crustáceos (CRUSTA), Praça Infante Dom Henrique, s/nº,CEP 11330–900, São Vicente, SP, Brazil Correspondence: M.A.A. Pinheiro; e-mail: [email protected] (Received 14 May 2018; accepted 2 October 2018) ABSTRACT Ocypodid crabs are common in mangrove areas, and the uçá, Ucides cordatus (Linnaeus, 1763), is a key species. It is abundant and economically relevant in these marine wetlands on the southeastern Atlantic coast of Brazil. Mangroves suffer from intense anthropogenic impact by pollutants affecting the reproductive biology of the animals inhabiting this ecosystem. We analyzed the reproductive potential of U. cordatus, comparing fecundity and fertility equations between two mangroves with distinct pollution levels in São Paulo state, Brazil: a pristine (Juréia-Itatins Ecological Station) and a contaminated (Cubatão) area. There was no differ- ence in egg production (fecundity) between crabs from both areas, possibly due to tolerance mechanisms exhibited by the crabs. There was, however, a substantial difference in larval production, which was three times higher in crabs from the contaminated mangrove than in those from the pristine mangrove. These results are explained by different reproductive condi- tions of the ovigerous females arising from the fertility analysis: primiparous (first spawning from the contaminated area) and multiparous females (second or subsequent spawning from the pristine area). Multiple spawning in the same reproductive season had not been previously reported for this species. Results, however, do not explain the relationship between environ- mental contaminants and fertility, which should be investigated in the future. Key Words: fecundity, fertility, reproductive biology, Ucidinae. INTRODUCTION Reproductive strategies in brachyurans vary with season, spawn- ing number, loss of eggs, and the spawning condition of females Ucides cordatus (Linnaeus, 1763) is a semi-terrestrial brachyuran (Sainte-Marie, 1993; Diez & Lovrich, 2010; Verísimo et al., 2011; crab typical of mangrove areas. The species is widely distributed Hartnoll, 2015; McLay & Becker, 2015). Reproduction can also in the western Atlantic (Melo, 1996) and is considered an impor- be affected by exogenous factors such as salinity, temperature, tant fishery resource (Diele et al., 2005) and a key species because photoperiod (Sastry, 1983; Bembe et al., 2017), and environmental crabs maintain energy and nutrients within mangrove forests by contamination (Depledge & Fossi, 1994; Penha-Lopes et al., 2009; recycling senescent leaves (Nordhaus et al., 2009). These crabs Almeida et al., 2016). Species respond in different ways to con- have a relevant role in environmental monitoring due to their taminants, showing tolerance that change with exposure time and high longevity (~10 years; Pinheiro et al., 2005), reduced mobil- concentration of pollutants (Depledge & Fossi, 1994). Estuarine ity (Nordhaus et al., 2009), endemism, and easy capture (Pinheiro species can be affected by local contamination (Harris & Santos, & Fiscarelli, 2001). They show seasonal reproduction (November 2000; Rotter et al., 2011) but some crustaceans have strategies to to March) with showing two peaks (December and February), survive when exposed to such contaminants (Ortega et al., 2016). each with a different frequency of ovigerous females (Pinheiro & One of the strategies is the synthesis of metallothionein, a protein Fiscarelli, 2001; Sant’Anna et al., 2014; Moraes et al., 2015). that binds metals (Bjerregaard et al., 2005; Gao et al., 2012). © The Author(s) 2018. Published by Oxford University Press on behalf of The Crustacean Society. All rights reserved. For permissions, please e-mail: [email protected] REPRODUCTIVE POTENTIAL OF UCIDES CORDATUS Studies on reproductive strategies help in the management of were removed with scissors and tweezers and transferred to 70% fishery resources, and previous contributions on this topic have ethyl alcohol for 48 h and subsequently to absolute alcohol for 72 h. been reported for U. cordatus (Nascimento, 1993; Góes et al., 2000; Each egg mass was dried (60 ºC) until weight was stabilized (~72 h). Sampaio, 2002; Pinheiro et al., 2003; Pinheiro & Hattori, 2003; Pleopod fragments and setae of each dry egg mass were removed Hattori & Pinheiro, 2003; Dalabona et al., 2005; Sant’anna et al., and discarded. Total dry weight of the egg mass was obtained using 2007; Castilho-Westphal et al., 2008, 2011, 2013; Wunderlich an analytical balance (to 0.0001 g precision). Fecundity was deter- et al., 2008; Sant’anna et al., 2014). Fecundity and fertility of Ucides mined by counting the number of eggs in three subsamples (0.3 mg cordatus have been studied by Pinheiro et al. (2003) and Hattori & each) under a stereomicroscope. Calculation of the total number of Pinheiro (2003), respectively. There are, nevertheless, studies show- eggs was performed by the rule of proportions, together with mean ing differences between egg and larval production from contami- number of eggs (NE) for each female. The coefficient of variation nated and pristine mangroves areas, which are relevant to optimal (CV) between three subsamples of each female was calculated to management (Pinheiro et al., 2003; Gonçalves & Reigada, 2012). avoid analytical error, with significant deviations substituted by Mangroves forests have been affected worldwide by anthropo- another counting when CV was larger than 15%. genic impact (e.g., Alongi, 2002; Duke et al., 2007; Abreu-Mota et al., A regression analysis of NE versus CW was performed using NE 2014). Such human pressure has been affecting mangroves along the as a dependent variable and CW as an independent variable; the central coast of São Paulo state, Brazil since European colonization empiric point was fitted by a power function (NE = aCWb). The Downloaded from https://academic.oup.com/jcb/article-abstract/39/1/74/5202066 by guest on 26 May 2020 starting in the 1500’s (Pinheiro et al., 2010). The port of Santos and fecundity equation was evaluated for each mangrove area accord- the Cubatão industrial complex are the main sources of pollution on ing to the determination coefficient (R2), considering R2 > 0.70 this coastal region (Luiz-Silva et al., 2006; Nascimento et al., 2006; as a good fit. Log-transformed data were compared by t-test for Zündt, 2006); stilt houses and untreated sewage are also important each mangrove area to evaluate possible differences between fitted (Pinheiro et al., 2012). Studies have looked at benthic macroinverte- curves. A significance level of 5% was used. brates such as U. cordatus as indicator of pollution aiming to obtain information about local anthropogenic conditions (Eisler, 2010; Fertility Duarte et al., 2017; Pinheiro et al., 2017). Recognizing the mecha- nisms that allow the survival of these species in highly stressful envi- Fertility is defined as the number of larvae hatched in a single batch, ronments is essential for studies of populations impacted by different and is related to female’s size (Sastry, 1983). Fertility was analyzed as levels of pollution (Ortega et al., 2016). We evaluated the reproduct- discussed by Hattori & Pinheiro (2003). Each ovigerous female in final ive strategies of U. cordatus, the uçá crab, by comparing fecundity embryonic stages was maintained in plastic recipients (3 l), with con- (number of eggs), fertility (number of hatched larvae), and hatching trolled salinity (15 ± 1 psu), temperature (26 ± 1 ºC) and photoperiod rate in a pristine (the Juréia-Itatins Ecological Station) and a polluted (12:12 h), until hatching. Larvae were transferred after hatching to a mangrove forest in the municipality of Cubatão. glass recipient and preserved in alcohol 70% until analysis. Each set of larvae released by a female was placed in a larger plastic recipi- ent with water (5 l) in constant aeration for the proper dispersion of MATERIALS AND METHODS larvae in the water column. Fertility was determined by quantifying the number of larvae in ten subsamples (2 ml) using a Stempel pip- Study area ette and calculating the mean by total volume extrapolation (5 l). The total number of larvae (NL) was determined per female by the rule of This study was conducted in two mangrove areas in São Paulo proportion, with sample elimination when CV > 15%. state, Brazil (Fig. 1) impacted by different levels of pollution Empirical points of NL versus CW relationship were submitted (Duarte et al., 2016, 2017): Cubatão, defined as a probably high to regression analysis, with NL the dependent variable and CW impacted (PHI) area and the Juréia-Itatins Ecological Station, the independent variable. These data were fitted by a power func- Peruíbe, defined as a probably non-impacted (PNI) area. tion (NL = aCWb) and confirmed by a determination coefficient (R2). The same procedure was applied to fecundity equations, with Sampling log-transformed