No abstract

This study provides the first record of the exotic invasive bivalve Isognomon bicolor for the State of Paraíba, Northeastern Brazil. It has been found to occur in at least twelve coastal reefs along the coast. We also present its first record for the State of Alagoas and new record localities for the States of Rio Grande do Norte and Pernambuco, including its occurrence in hypersaline estuaries. From these records the distribution range of I. bicolor has been expanded to the littoral region of Northeast Brazil, where this invasive species seems well established.

Spawning ofCassis tuberosais recorded and described for the first time, based on observations carried out in the Tamandaré reefs, north-eastern Brazil. The specimen was laying over gravel substrate surrounded by macroalgae at a depth of 2 m.Cassis tuberosauses an algal frond of the genusPadinato lay its eggs. The oothecae consists of approximately 200 vasiform capsules, orange in colour. The spawn ofCassis tuberosais quite similar to that produced by its congener,Cassis madagascariensis; however,Cassis tuberosaspawns in the soft substrate provided by algal fronds whileCassis madagascariensisutilizes coarse, carbonate sand. Considering thatCassis tuberosais the target of multiple commercial purposes, to expand our knowledge about its biology could contribute towards protecting the essential habitat of reproductively active individuals.

Cassis tuberosa is one of the most exploited marine gastropods on the Brazilian coast, due to its aesthetic value. The lack of characterization of the species' trade makes it difficult to establish effective monitoring strategies. This is the first survey to characterize the fishing and trade chain of C. tuberosa, and to record aspects of local fishermen's traditional ecological knowledge of the species. C. tuberosa is caught while fishing for other target resources, such as fish, lobsters, and octopuses. The most popular use of the shell is for ornamental purposes, and the demand for this is enhanced by the intensive tourism. Knowledge of capture techniques and species usefulness is transmitted vertically in the community. The local ecological knowledge points to a population decline over time and attributes such decline to increased fishing. We hope the characterization provided in this study will contribute to the effective management of this species.