Lethargic crab disease: multidisciplinary evidence supports a mycotic etiology

Boeger, Walter A.; Pie, Márcio R.; Ostrensky, Antônio; Patella, Luciana

doi:10.1590/s0074-02762005000200009

Cited by 70 publications

(66 citation statements)

References 11 publications

(9 reference statements)

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“…The present study focuses on Ucides cordatus cordatus (Linnaeus, 1763) (hereafter referred to as U. cordatus), a large commercially exploited ocypodid crab which occurs in mangrove forests along the subtropical and tropical Atlantic coast of the Americas (Türkay, 1970). In many regions of Brazil crabs are threatened by habitat destruction, diseases and fishery (Nordi, 1994;Botelho et al;2000, Alves et al, 2005Boeger et al, 2005). In our study area, 320 km southeast of the Amazon mouth, the local Ucides population is still comparably healthy (Glaser and Diele, 2004;Diele et al, 2005), but fishing pressure is increasing due to demographic growth and adequate management strategies are currently being discussed.…”

Section: Introductionmentioning

confidence: 83%

Salinity tolerance of northern Brazilian mangrove crab larvae, Ucides cordatus (Ocypodidae): Necessity for larval export?

Diele

Simith

2006

Estuarine, Coastal and Shelf Science

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The life cycle of the semi-terrestrial mangrove crab Ucides cordatus includes pelagic larvae that are released into estuarine waters during the wet season and who may thus encounter potentially stressful low and variable salinity conditions. The effect of salinity on the survival of the zoea larvae, the number of zoeal stages and the duration of development from hatching to megalopa was experimentally studied by rearing larvae from the Caeté estuary, N-Brazil, in seven salinity treatments (0, 5, 10, 15, 20, 25, and 30). For a better interpretation of the laboratory results, estuarine salinities were measured over five consecutive years during the species´ reproductive season. The survival of the zoea larvae varied significantly with salinity, while the number of stages and the duration of their development remained 2 constant. Development to megalopa took 20.77 ± 1.57 days and comprised five zoeal stages with ZI and ZII being euryhaline and later stages stenohaline. The newly hatched larvae stayed alive for up to six days in freshwater (average 4.32 ± 0.82 days), but did not moult to the second zoeal stage. ZII larvae first occurred from salinity 5 onwards and later zoeal stages at all tested salinities ≥ 10. However, the larvae only survived to megalopa at salinities ≥ 15, with highest numbers at salinity 30 (72%) and lowest at 15 (16%). Lethal salinities ≤ 10 occurred frequently in the estuary during the reproductive season. This suggests a need for larval export to offshore and thus more saline waters to allow for significant larval survival and maintenance of viable populations of this commercially important species. A regional rather than local approach for management is suggested due to the likelihood of long distance larval dispersal by off-shore currents.

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Section: Introductionmentioning

confidence: 83%

Salinity tolerance of northern Brazilian mangrove crab larvae, Ucides cordatus (Ocypodidae): Necessity for larval export?

Diele

Simith

2006

Estuarine, Coastal and Shelf Science

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“…Declines of U. cordatus have been reported from many coastal regions of Brazil and were related to habitat destruction, diseases and overfishing (Maneschy 1993;Boeger et al 2005). In the Caeté estuary, the mangrove forest habitat of U. cordatus is still comparably intact, however there is growing concern that the fishery and the population might collapse due to increasing fishing pressure.…”

Section: Introductionmentioning

confidence: 99%

Population structure, catch composition and CPUE of the artisanally harvested mangrove crabUcides cordatus(Ocypodidae) in the Caeté estuary, North Brazil: Indications for overfishing?

Diele

Koch

Saint-Paul

2005

Aquat. Living Resour.

131

110

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-To evaluate the population structure of Ucides cordatus in the Caeté estuary, crabs were sampled bimonthly over 13 months in three Rhizophora mangle forest stands that differed in their accessibility and fishing history. Additionally, sex-and size composition of the commercial catch and catch per unit of effort (CPUE -the number of crabs captured per fisherman per day) were monitored between 1997 and 2003. Average and maximum crab sizes (carapace width, CW) from all three sampling sites combined were 6.1 cm and 8.8 cm in males, respectively, and 5.5 and 7.3 cm in females. Crabs were largest at the site that had been reportedly less exploited in the past. The overall sex ratio was skewed towards males (53−62%). Egg carrying females were only encountered during the rainy season. Mean crab abundance and biomass was 1.7 specimens m −2 and 142 g m −2 fresh mass. Only large males were commercially harvested (98% ≥ 6.5 cm CW). Their biomass was 53 g m −2 and the Caeté estuary yields an annual production of 1200 t of these large specimens. This is approximately the quantity that is currently being harvested. CPUE was similar in 1997 and 1998, then decreased by 15% until 2000 and stabilized for the rest of the study period. Mean capture size (cm CW) ranged between 7.2 ± 0.5 and 7.5 ± 0.2 and was above the size of 50% (and even 100%) male maturity and the legal minimum capture size. There is no evidence that the Caeté crab population is overfished, despite over 30 years of de facto open access exploitation. Apparently, the selectivity of fishermen and consumers for large male crabs as well as the local artisanal capture techniques are key factors in preventing an overfishing of the Caeté crab population until today. Our results suggest that the economic and social sustainability of this fishery will be affected well before the biological one, which should be considered in the recently proposed coastal co-management plan for the region. Key words:Mangrove crab / Ucides cordatus / Biomass / Sex ratio / Artisanal fisheries / CPUE / Management / Brazil Résumé -Structure de la population, composition des captures et CPUE du crabe de mangrove Ucides cordatus (Ocypodidae) capturé artisalement dans l'estuaire du Caeté, nord Brésil : signes de surexploitation ? Pour évaluer la structure de la population de Ucides cordatus dans l'estuaire du Caeté, ces crabes ont été échantillonnés tous les deux mois, sur une période de 13 mois, au niveau de trois sites de la mangrove à Rhizophora mangle qui diffèrent par leur accessibilité et leur historique de pêche. De plus, la composition (sexe et taille) des captures commerciales et celle par unité d'effort (CPUE -nombre de crabes capturés par pêcheur et par jour) ont été suivies entre 1997 et 2003. La taille moyenne et la taille maximale des crabes (largeur de la carapace, CW) de l'ensemble des 3 sites échantillonnés étaient de 6,1 et 8,8 cm pour les mâles, respectivement, et 5,5 et 7,3 cm pour les femelles. Les crabes étaient plus grands dans le site qui avait été moins exploité pa...

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“…Os machos atingem 160 mm de largura da carapaça e, as fêmeas, 150 mm (Tavares, 2002b Estado do Pará e na região Nordeste, podendo haver suspensão da captura durante as andadas (Mota, 2005). É importante mencionar a doença letárgica causada por fungos e que tem provocado mortalidade massiva nas populações do caranguejouçá na Bahia (Boeger et al, 2005).…”

Section: Crustáceosunclassified

Baía de todos os santos: aspectos oceanográficos

Andrade¹,

Hatje²

2009

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Este livro agrega informações que subsidiam o entendimento da oceanografia da Baía de Todos os Santos. Propicia o embasamento científico para a interpretação de sua situação atual com vistas ao planejamento de futuros projetos de pesquisa e de ações gerenciais que venham a garantir a recuperação e a preservação de sua riqueza natural, como recifes de corais, estuários, manguezais, bem como a promoção da qualidade de vida das populações do Recôncavo Baiano.

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Lethargic crab disease: multidisciplinary evidence supports a mycotic etiology

Abstract: Although lethargic crab disease (LCD) is causing massive mortalities in populations of the mangrove crab

Cited by 70 publications

References 11 publications

Salinity tolerance of northern Brazilian mangrove crab larvae, Ucides cordatus (Ocypodidae): Necessity for larval export?

Salinity tolerance of northern Brazilian mangrove crab larvae, Ucides cordatus (Ocypodidae): Necessity for larval export?

Population structure, catch composition and CPUE of the artisanally harvested mangrove crabUcides cordatus(Ocypodidae) in the Caeté estuary, North Brazil: Indications for overfishing?

Baía de todos os santos: aspectos oceanográficos

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