Fish fauna associated to mangrove roots at the Pacoti River estuary

Abstract

The mangrove vegetation along the margins of estuaries is an important habitat for fish, serving as feeding, shelter and nursery zones. The present work describes the fish fauna associated to mangrove roots at the Pacoti River estuary. A total of ten visual censuses of 90 minutes each were conducted, yielding the number of 671 fish counted, with an average of 0.74 counts/minute. The fishes were identified pertaining to 22 species from 18 different families. All the studied species are originally marine, although the samples were mainly carried out during the rainy season. Gerreidae and Lutjanidae were the more representative families. The species Lutjanus alexandrei, Lutjanus jocu and Bathygobius soporator were present in all censuses and the first two were also the most abundant, with 48 and 17% of the total counts, respectively. Taking into account size estimations of the fish, it was verified that mangrove roots are inhabited mainly by juveniles of both species, indicating the use of this habitat as a nursery area. However, in the least complex sampling site, specimens of genus Lutjanus were sought in higher quantities, comprinsing all size classes, thus suggesting the abundance of roots in Pacoti River might not influence the abundance of sheltered fishes. Another important observation is that almost 70% of the species present in the mangrove roots are typical of reef habitats, indicating the existence of strong connections between these two ecosystems. The results emphasize the importance of this habitat for ichthyofauna conservation to coastal areas. In addition, studies regarding to fish recruitment, reproductive and trophic patterns are needed, especially to those two main important species described herein.