Mangrove fish assemblages from data-sparse regions and the measurement of ecological equivalence: Comment on Sheaves (2012)

Abstract

The global comparison of mangrove fish assemblages and their ecological equivalence by Sheaves (2012; Mar Ecol Prog Ser 461:137−149) presents useful novel information for this specific ecosystem faunal assemblage. This comparison, however, included only a single study from the tropical Eastern Pacific region (TEP), which was assigned to an Eastern Central Atlantic group. Here, we present data that supplement the analysis made by Sheaves and show that the taxonomic composition (at the family level) of the TEP mangrove fish fauna is considerably different from the Eastern Central Atlantic, and warrants a different classification. To characterize TEP mangrove fish fauna, we used the same descriptors as in Sheaves (2012) (i.e. % of families with widespread vs. restricted distributions, and their affinity with families characteristic of coral reefs). Based on our analysis, the estuarine mangrove fish assemblages from the Neotropical region (TEP and Western Central Atlantic) substantially differ—both taxonomically and functionally—from the ones at the West African coast (tropical Eastern Atlantic) so that overall, Sheaves’ (2012) Eastern Central Atlantic group likely consists of 3 groups: TEP, Western Central Atlantic and tropical Eastern Atlantic. An examination of the relative abundance and biomass of fish families revealed striking differences in their representativeness, especially between Neotropical and tropical Eastern Atlantic assemblages. Therefore, further comparisons of ecological equivalence should use metrics with a higher ecological resolution (i.e. biomass) than the ones employed by Sheaves (2012), giving a more meaningful basis to compare mangrove fish assemblages worldwide.