Macroecology of population dynamics and life history traits of the mole crab Emerita brasiliensis in Atlantic sandy beaches of South America

Defeo, Omar; Cardoso, Ricardo S.

doi:10.3354/meps239169

Cited by 79 publications

(74 citation statements)

References 33 publications

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“…7: y = 6.77-0.04x, r = 0.94, P \ 0.05, N = 12). This trend provides support to the latitudinal gradient hypothesis of marine invertebrates (Defeo and Cardoso 2002), which predicts a positive correlation between body size and latitude: populations from subtropical beaches exhibited higher growth and mortality rates and shorter lifespans than those of temperate beaches. However, this observation would be better understood if growth studies on several populations could be linked to quantitative and qualitative data regarding phytoplankton.…”

Section: Growth and Growth Performancesupporting

confidence: 75%

Population structure, growth and production of the yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae) from a high-energy, temperate beach in northern Argentina

et al. 2010

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The yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae) was once the most abundant intertidal species on the Atlantic coast of northern Argentina and an important commercial resource in South America. This study of a population inhabiting the intertidal zone of the sheltered-dissipative sandy beach Santa Teresita documents the species' population biology, including demographic structure, growth and production during December 2004 and December 2006, and adumbrates the critical state of M. mactroides at present. A total of 3,015 M. mactroides were collected and measured, whereas individuals were found with an anterior-posterior shell length between 2 and 64 mm. A von Bertalanffy growth function with an asymptotic length (L ? ) of 85 mm and a growth constant (K) of 0.47 year -1 was established from length-frequency distributions. The longevity of the species is estimated at approximately 6 years, and instantaneous mortality rate was about three times higher than 40 years ago. Besides, this study confirmed that the overall growth performance index (OGP) is habitat-specific and can be used to group M. mactroides and M. donacium from different areas into temperate and upwelling species. Furthermore, OGP is inversely correlated with the latitudinal distribution of Mesodesma populations. The intertidal biomass ranged between 0.06 and 0.07 g AFDM m -2 year -1 . Individual production was observed to be highest at 47 mm length (0.35 g AFDM m -2 year -1 ), and annual production ranged between 0.12 and 0.19 g AFDM m -2 year -1 , resulting in productivity values (P/B) between 1.84 and 2.93. The comparison of the results of the present study with those of growth studies conducted on M. mactroides 40 years ago revealed the following considerable differences in the population structure of M. mactroides, indicating the conservation status of this intertidal bivalve as endangered: (1) present growth rates are faster, but that the maximum length attained has decreased, (2) the numbers of individuals per square metre were many times higher in the past than in the present, (3) bivalves from the present work never reached the 'commercial size' of 60 mm and (4) 40 years ago, the population of M. mactroides was composed of up to three cohorts, whereas in this study, there was only one single cohort visible.

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Section: Growth and Growth Performancesupporting

confidence: 75%

Population structure, growth and production of the yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae) from a high-energy, temperate beach in northern Argentina

et al. 2010

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“…In contrast, males can be found more often outside the burrows, thus making them more vulnerable to bottom trawling. However, bias in the sex ratio is very common in decapods (Wenner 1972), and has also been attributed to latitudinal (Defeo & Cardoso 2002, Rivadeneira et al 2010 and temporal variations (Wenner 1972, Bas et al 2005. Although our data does not allow any robust conclusion about the observed predominance of males, we cannot exclude the possibility that females migrate (temporarily) out of our study area or into the water column, causing the observed bias.…”

Section: Population Demography Spatial Distribution and Behaviour Ofcontrasting

confidence: 48%

Population demography and spatial distribution of the mantis shrimp Squilla biformis (Stomatopoda, Squillidae) from Pacific Costa Rica

Hernáez¹,

Clarke²,

Benavides-Varela³

et al. 2011

Mar. Ecol. Prog. Ser.

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The mantis shrimp Squilla biformis is the most conspicuous and abundant stomatopod captured during benthic trawling operations off the Pacific coast of Costa Rica. Due to its abundance, this species is considered a potential fisheries resource for the region. Nevertheless, its life history is practically unknown. The present study describes the population demography, spatial distribution and behaviour of S. biformis from Pacific Costa Rica. The population was principally composed of individuals between 20 and 32 mm carapace length (CL), forming 2 age groups. Individuals of 35 to 45 mm CL and > 45 mm CL were poorly represented. We assume that larger individuals are more frequent at greater depths (probably on the continental slope), thus out of the reach of the fishing vessels used in our study. Males outnumbered females, as observed in other stomatopods. Visual evidence of their behaviour demonstrates that the adults in this species possess a benthic and pelagic life style. Largest numbers of individuals (50% of the total) were found between 240 to 260 m, the same bathymetric range that was historically occupied by commercial shrimps. This shift may be related to intense fishing activities. We observed a synchronized moulting of females and males during less luminous (third and fourth) lunar phases. The evolutionary development of a group moulting system could confer advantages to S. biformis in comparison to other stomatopods whose moulting process is individual and asynchronous.

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“…The simple source-sink model depicted here suggests that differences between beach categories are extreme. In this sense, mole crab populations in highquality source habitats (dissipative beaches) should have, on average, a positive rate of increase, as suggested in recent macroscale studies of the species throughout its range (Defeo & Cardoso 2002. This is also consistent with the universally accepted perception of dissipative beaches as self-sustaining or semi-closed ecosystems, where the beach itself and a surf zone that is extremely rich in surface phytoplankton provide high amounts of food (Defeo & McLachlan 2005) for filter feeders such as Emerita brasiliensis.…”

Section: Discussionmentioning

confidence: 99%

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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Macroecology of population dynamics and life history traits of the mole crab Emerita brasiliensis in Atlantic sandy beaches of South America

Cited by 79 publications

References 33 publications

Population structure, growth and production of the yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae) from a high-energy, temperate beach in northern Argentina

Population structure, growth and production of the yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae) from a high-energy, temperate beach in northern Argentina

Population demography and spatial distribution of the mantis shrimp Squilla biformis (Stomatopoda, Squillidae) from Pacific Costa Rica

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

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