Reproductive plasticity in mole crabs, Emerita brasiliensis, in sandy beaches with contrasting morphodynamics

Delgado, Estela; Defeo, Omar

doi:10.1007/s00227-007-0879-6

Cited by 8 publications

(8 citation statements)

References 21 publications

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“…At the population level, the Habitat Harshness Hypothesis (HHH: Defeo et al 2003) predicts that the harsh environment in reflective beaches forces organisms to invest more energy in maintenance than in reproduction and growth, result-ing in lower abundance, fecundity, growth and survival rates than in dissipative beaches. In agreement with SEH and HHH predictions, studies conducted worldwide have shown a consistent decrease in community (McLachlan 1990, Defeo et al 1992, McLachlan et al 1993, Jaramillo et al 2000, Soares 2003, Rodil & Lastra 2004, McLachlan & Dorvlo 2005 and population (truly intertidal species: Nel et al 2001, de la Huz et al 2002, Contreras et al 2003, Celentano & Defeo 2006, Delgado & Defeo 2008, Thompson & Sánchez De Bock 2009 indicators from dissipative to reflective beaches (but see Herrmann 2009).…”

Section: Introductionmentioning

confidence: 58%

Effects of morphodynamic and estuarine gradients on the demography and distribution of a sandy beach mole crab: implications for source–sink habitat dynamics

Celentano¹,

Gutiérrez²,

Defeo³

2010

Mar. Ecol. Prog. Ser.

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Several conceptual models relating biological and morphodynamic variables have been developed in sandy beach ecology. On estuarine sandy beaches, a major environmental factor influencing macrofaunal distribution is salinity. In this setting, the concurrent role of large-scale estuarine and morphodynamic gradients in shaping demographic patterns is still uncertain. To explain largescale variations in demographic aspects of the mole crab Emerita brasiliensis, 16 Uruguayan sandy beaches distributed along the estuarine gradient generated by the Rio de la Plata were characterized in terms of beach morphology, sediment traits and salinity over a 2 yr period. Abundance (total and discriminated by reproductive and recruitment components), biomass and body size of E. brasiliensis significantly increased from estuarine reflective to oceanic dissipative beaches. Further, generalized models (both additive and linear) showed that salinity, mean grain size and swash width were the most important explanatory factors of spatio-temporal variations in abundance. Sexually mature individuals and megalopae were almost absent in estuarine and oceanic reflective beaches, whereas oceanic dissipative beaches showed polymodal size structures with fully represented population components, together with extended reproductive and recruitment periods. We conclude that (1) morphodynamic and estuarine gradients are inextricably linked, affecting mole crab demography; and (2) estuarine and oceanic reflective beaches operate as sink habitats where populations do not prosper, whereas oceanic dissipative beaches act as source habitats. We thus provide empirical support to the source-sink hypothesis recently developed for sandy beaches. These long-term variations in demographic processes should be complemented by connectivity studies and genetic analyses in order to gain a deeper understanding of metapopulation dynamics in sandy beaches.KEY WORDS: Mole crab · Emerita · Demography · Salinity · Sandy beaches · Morphodynamics · Generalized additive models 398: 193-205, 2010 ing in lower abundance, fecundity, growth and survival rates than in dissipative beaches. In agreement with SEH and HHH predictions, studies conducted worldwide have shown a consistent decrease in community (McLachlan 1990, Defeo et al. 1992, McLachlan et al. 1993, Jaramillo et al. 2000, Soares 2003, Rodil & Lastra 2004, McLachlan & Dorvlo 2005 and population (truly intertidal species: Nel et al. 2001, de la Huz et al. 2002, Contreras et al. 2003 In relation to the patterns found at the population level, it has been postulated that post-settlement processes prevent intertidal species from establishing populations on reflective beaches. Moreover, it has been hypothesized that dissipative beaches can act as 'source' habitats, whereas reflective beaches would constitute 'sink' habitats where reproduction patterns of resident species are insufficient to balance mortality. This has been called the 'source-sink hypothesis' for intertidal sandy beach populations (Defeo & McLac...

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Section: Introductionmentioning

confidence: 58%

Effects of morphodynamic and estuarine gradients on the demography and distribution of a sandy beach mole crab: implications for source–sink habitat dynamics

Celentano¹,

Gutiérrez²,

Defeo³

2010

Mar. Ecol. Prog. Ser.

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“…Delgado & Defeo (2008) reported a M : F ratio of 1.35 : 1, while Osorio et al (1967) found a much more balanced proportion in the case of E. analoga (1.05 : 1). These results contrast with data provided for E. emeritus by Boonruang & Phasuk (1975) who found a sex proportion clearly in favour of females (0.2287 : 1, i.e., over 4 females for each male), a situation which we also observed with E. rathbunae (M : F, 1 : 1.5) although not as strongly marked as in the Asiatic species.…”

Section: Discussionmentioning

confidence: 92%

“…According to Efford (1967), in Emerita difference in length between sexes is related to neoteny in males, for its earliness in the process of sexual maturation. It should be added that several authors (e.g., Subramoniam, 1977;Delgado & Defeo, 2006) indicate that Emerita may have a degree of hermaphroditism in which males go through an intersexual state before becoming females (protandrous hermaphrodites) and continue to grow (Lacadena, 1998), which justifies the difference in the maximum length observed between sexes as there is a clear limit of the potential maximum size reached by males.…”

Section: Discussionmentioning

confidence: 96%

“…Subsequently, a large series of contributions, many on E. analoga, E. brasiliensis Schmitt, 1935, andE. asiatica (H. Milne Edwards, 1837) (= E. emeritus Linnaeus, 1767) were produced, including aspects related to distribution (e.g., Fusaro, 1980;Jaramillo et al, 2000a), reproduction (e.g., Subramoniam, 1977Subramoniam, , 1979Subramoniam, , 1981Subramoniam, , 1984Wenner & Haley, 1981;Sastre, 1991;Dugan et al, 1994;Contreras et al, 2000;Delgado & Defeo, 2006), general biology (e.g., Díaz, 1980Wenner et al, 1993), morphology (e.g., Knox & Boolootian, 1963), population dynamics (e.g., Veloso & Cardoso, 1999;Jaramillo et al, 2000b;Petraco et al, 2003), fishery (e.g., Boonruang & Phasuk, 1975) and larval development (e.g., Knight, 1967;Díaz & Costlow, 1987).…”

Section: Introductionmentioning

confidence: 99%

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Abundance, relative growth and fecundity of Emerita rathbunae Schmitt, 1935 (Decapoda, Anomura, Hippidae) in the S.E. Gulf of California, Mexico

Ríos-Elósegui

Hendrickx

2015

Crustac

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Specimens of the mole crab Emerita rathbunae Schmitt, 1935, were collected during a one-year period along two sandy beaches in the S.E. Gulf of California, Mexico. A total of 2171 specimens were examined. Only 8% of the collected females were ovigerous. The large majority of males (95%) were collected in the sand as "free living" males, while the rest (39 individuals) were "dwarf males", with developed genital papilla, 95% of which were found attached to females. Density for pooled samples reached an overall maximum of 309.8 orgs/m 2 in February and a minimum in April (65.0 orgs/m 2 ). Females always outnumbered males, except in February. Ovigerous females were observed in the first half of the study period (February to September). Proportions of males were very similar throughout the study period, while indeterminate specimens were proportionally more abundant in its second half. Relationships between CW and CL for both males and females were highly correlated and isometric. Relationships between size and weight were highly correlated in both males and non-ovigerous females for pooled samples or for each sampling zone, and in each case growth was isometric. The number of eggs per ovigerous female varied considerably, from 910 to 22 866, and the relationship between number of eggs per batch and body size was poorly correlated. In the study area, E. rathbunae appears to have a rather restricted reproduction period. A larger series of data combined with the analysis of other environmental factors, such as beach profiles, current patterns and primary productivity, might bring some additional information on this species biology and ecology. Due to the key role that mole crabs play in the food web of sandy beaches, special attention should be provided to this particular habitat. RÉSUMÉDes spécimens du mui-mui du Pacifique, Emerita rathbunae Schmitt, 1935, ont été récoltés Durant un an le long de deux plages sableuses dans le S.E. du golfe de Californie, Mexique. Un total de 2171 spécimens ont été examinés. Seulement 8% des femelles étaient ovifères. La grande majorité des mâles (95%) furent ramassés dans le sable (mâles libres), tandis que le reste (39 individus) correspondait à des "mâles nains" possédant des papilles génitales bien développées, 95% de ceux-ci étant attachés a des femelles. Les densités d'organismes observées pour l'ensemble des échantillons fut d'un maximum de 309,8 orgs/m 2 en février et d'un minimum de 65,0 orgs/m 2 en avril. Les femelles furent toujours plus nombreuses que les males, sauf en février. Les femelles ovifères furent observées durant la première moitié de la période d'échantillonnage (février à septembre). La proportion de mâles s'est maintenue très stable durant toute l'étude, tandis que les spécimens indéterminés furent plus abondants durant sa seconde moitié. Les relations entre la largeur et la longueur de la carapace chez les mâles et les femelles indiquèrent un fort coefficient de corrélation et un comportement isométrique. Il en fut de même dans le cas des relations entre la ta...

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“…in temporally and spatially variable environments such as estuaries, small-scale heterogeneity in those factors may therefore contribute to intraspecific variability in egg characteristics, causing intra-and inter-populational variation in embryonic quality. There are many studies related to differences in size and biochemical composition of crustacean eggs comparing geographically separated populations (Jones and Simons, 1983;Wehrtmann and kattner, 1998;lardies and Castilla, 2001;lardies and Wehrtmann, 2001;Bas et al, 2007, delgado anddefeo, 2008), whereas comparative studies between contrasting habitats of the same population are less commonly found in the scientific literature. This aspect of intraspecific variability is addressed in the present study.…”

Section: Introductionmentioning

confidence: 99%

Rasgos reproductivos de un cangrejo estuarino <i>Neohelice (</i>= <i>Chasmagnathus) granulata</i> (Brachyura: Grapsoidea: Varunidae) en dos hábitats contrastantes

Silva¹,

Luppi²,

Spivak³

et al. 2009

Sci. Mar.

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² Consejo nacional de investigaciones Científicas y Técnicas (CONICET) 3 Biologische anstalt Helgoland, Stiftung alfred-Wegener-institut für Polar-und meeresforschung, meeresstation, 27498 Helgoland, germany.SummarY: reproductive traits of an estuarine crab, Neohelice (= Chasmagnathus) granulata (dana 1851), were compared between individuals living in contrasting habitats (mudflat and saltmarsh) of the same population in the brackish coastal lagoon of mar Chiquita, argentina. in both habitats, most measures of egg biomass decreased during embryogenesis, including total dry weight (dW) and organic matter (measured as ash-free dry weight, aFdW) per egg, the contents of ash, carbon, hydrogen and nitrogen (per egg and as percentage values of dW), the energy content (estimated from C; both per egg and per mg dW), and the C/n and C/H mass ratios. Egg size, wet weight (WW), and water content (in µg and % of WW), by contrast, increased significantly during the time of embryonic development. These parameters reached significantly higher final (near-to-hatching) values in mudflats than in saltmarshes (egg volume 0.0249 vs 0.0233 mm 3 ; WW 36.5 vs 28.8 µg; water content 30.7 vs 23.2 µg per egg or 84.2 vs 80.2% of WW, respectively). Fecundity and reproductive effort did not differ significantly between habitats. Habitat-specific differences in the water content and size of crab eggs are discussed in relation to small-scale local variation in environmental conditions.Keywords: Neohelice, Chasmagnathus, estuary, fecundity, reproductive effort, egg volume, elemental composition (CHn).rESumEn: Rasgos reproductivos de un cangrejo estuarino Neohelice (= chasmagNathus) graNulata (Brachyura: Grapsoidea: Varunidae) en dos hábitats contrastantes. -los rasgos reproductivos del cangrejo estuarino, Neohelice (= Chasmagnathus) granulata, fueron comparados entre individuos que viven en hábitats contrastantes (planicie de marea y marisma) en una misma población de la laguna costera salobre de mar Chiquita, argentina. En ambos hábitats, la mayoría de las mediciones de biomasa de los huevos disminuyeron durante la embriogénesis, incluyendo el peso seco total (dW) y la materia orgánica (medida como peso seco libre de ceniza, aFdW) por huevo, el contenido de ceniza, carbón, hidrógeno y nitrógeno (por huevo y como valores porcentuales de dW), el contenido de energía (estimado a partir del C; por huevo y por mg dW), y la proporción de C/n y C/H. El tamaño del huevo, peso húmedo (WW), y contenido de agua (en % de WW), por el contrario, aumentaron significativamente durante el tiempo de desarrollo embrionario. Estos parámetros alcanzaron valores finales (cerca de la eclosión) significativamente más altos en la planicie de marea que en la marisma (volumen de los huevos 0.0249 vs 0.0233 mm 3 ; WW 36.5 vs 28.8 µg; contenido de agua 30.7 vs 23.2 µg por huevo y 84.2 80.2% WW; respectivamente). la fecundidad y el esfuerzo reproductivo no difieren significativamente entre ambos hábitats. las diferencias vinculadas al hábitat en el contenido de agua y ta...

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Reproductive plasticity in mole crabs, Emerita brasiliensis, in sandy beaches with contrasting morphodynamics

Cited by 8 publications

References 21 publications

Effects of morphodynamic and estuarine gradients on the demography and distribution of a sandy beach mole crab: implications for source–sink habitat dynamics

Effects of morphodynamic and estuarine gradients on the demography and distribution of a sandy beach mole crab: implications for source–sink habitat dynamics

Abundance, relative growth and fecundity of Emerita rathbunae Schmitt, 1935 (Decapoda, Anomura, Hippidae) in the S.E. Gulf of California, Mexico

Rasgos reproductivos de un cangrejo estuarino <i>Neohelice (</i>= <i>Chasmagnathus) granulata</i> (Brachyura: Grapsoidea: Varunidae) en dos hábitats contrastantes

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