Presença do vírus da síndrome da mancha branca em crustáceos decápodes silvestres em lagoas costeiras no Sul do Brasil

A presença do vírus da síndrome da mancha branca (em inglês WSSV) nas principais espécies de camarões, siris e caranguejos de cinco lagoas que recebem o efluente de fazendas afetadas pela enfermidade foi detectada por nested PCR, e inclusões virais nos camarões por histologia. Pela nested PCR encontrou-se a presença de WSSV em 13 de 16 (81,2%) amostras de camarões da espécie Farfantepenaeus paulensis, em 13 de 14 (92,8%) de Litopenaeus schmitti, em uma de duas de Farfantepenaeus brasiliensis (50%), em 13 de 15 (86,6%) de siri da espécie Callinectes danae e em 11 de 12 (91,6%) de Callinectes sapidus, e não foi detectada no caranguejo Chasmagnathus granulata em 10 amostras. Inclusões características de WSSV foram observadas em três amostras histológicas de 50 (6,0%) no epitélio gástrico e cuticular e nas brânquias de dois exemplares de F. paulensis e um de L. schmitti. É o primeiro relato da presença de WSSV em camarões L. schmitti e no siri C. danae silvestres. As principais espécies de camarões e siris dos ambientes de entorno das fazendas foram contaminadas pelo WSSV, constituindo-se em vetores potenciais do vírus.

Selection of shrimp breeders free of white spot syndrome and infectious hypodermal and hematopoietic necrosis

The objective of this work was to select surviving breeders of Litopenaeus vannamei from white spot syndrome virus (WSSV) outbreak, adapted to local climatic conditions and negatively diagnosed for WSSV and infectious hypodermal and hematopoietic necrosis virus (IHHNV), and to evaluate if this strategy is a viable alternative for production in Santa Catarina, Brazil. A total of 800 males and 800 females were phenotypically selected in a farm pond. Nested-PCR analyses of 487 sexually mature females and 231 sexually mature males showed that 63% of the females and 55% of the males were infected with IHHNV. Animals free of IHHNV were tested for WSSV, and those considered double negative were used for breeding. The post-larvae produced were stocked in nine nursery tanks for analysis. From the 45 samples, with 50 post-larvae each, only two were positive for IHHNV and none for WSSV. Batches of larvae diagnosed free of virus by nested-PCR were sent to six farms. A comparative analysis was carried out in growth ponds, between local post-larvae and post-larvae from Northeast Brazil. Crabs (Chasmagnathus granulata), blue crabs (Callinectes sapidus), and sea hares (Aplysia brasiliana), which are possible vectors of these viruses, were also evaluated. The mean survival was 55% for local post-larvae against 23.4% for post-larvae from the Northeast. Sea hares showed prevalence of 50% and crabs of 67% of WSSV.

Differential coloration patterns in the intertidal crab Neohelice (=Chasmagnathus) granulata

Many crustaceans with spatial segregation may present differential body coloration depending on the habitat they inhabit. Since crustaceans are unable to synthesize carotenoids, individuals must acquire them from their diet, so diet changes can modify individual coloration. The burrowing crab Neohelice (=Chasmagnathus) granulata inhabits the intertidal, from the uppermost parts of salt marshes to the lowest mudflat zones with a spatial segregation of different size-classes. They are primarily deposit feeders in mud flats and herbivorous–detritivorous in the salt marsh. We analysed the effect of intermoult length on the carapace colour of N. granulata, and the changes in carapace colour with crab size and zone. Crab colour varied between unvegetated and vegetated areas. Some of these differences were in part caused by colour changes related to crab size. Larger crabs show less intensive colours, and given that they inhabit the upper part of the intertidal a differential coloration pattern occurred between zones. In field experiments intermoult duration affected crab colour and some body regions analysed showed differences between zones unrelated to size.