Friday, August 23, 2019

Drivers of abundance and biomass of Brazilian parrotfish

During the past weeks Natalia Roos, member of the FEME, published her first PhD chapter in the MEPS 40th Anniversary volume.
 
Here below a little summary. If you want to check the entire paper checks here:
 
 
 
 
The large Brazilian coast encompasses most of the reef environments in the southwestern Atlantic, which are characterized by unique reef formations and high rates of endemism. Parrotfishes (Labridae: Scarinae) are among the most ubiquitous and dominant reef fish worldwide, and in Brazil the group is composed by 60% of endemic species (i.e. six species). It is known that parrotfishes may affect the physical structure and composition of benthic communities through the grazing and bioerosion. Despite their ecological importance, parrotfishes have been intensively target in many regions worldwide. In Brazil four endemic species are now threatened at some level due overfishing, including the largest Brazilian parrotfish Scarus trispinosus, which may reach up to 90 cm of total length. Signs of depletion of these species bolster our need to understand their patterns of abundance and biomass, habitat preferences and assemblage structure across different reef types inform conservation and management. We assessed abundance and size class distributions of six parrotfishes in northeastern Brazil and identified habitat preferences based on reef attributes. Species distributions were variable and related to their respective feeding modes and reef types. Such heterogeneity in habitat use is suggestive of functional complementarity rather than functional redundancy among Brazilian parrotfish assemblages. Moreover, outer-shelf reefs sustained larger individuals for most of the species, whereas inner-shelf reefs supported higher abundances of small individuals. Despite being nurseries or developing areas, shallow inshore reefs sustain intense artisanal fishing activities targeting parrotfishes. The ongoing fishing pressure in nursery habitats may be causing significant declines in adult numbers in deeper outer shelf reefs that are yet to be quantified. Such information may have important implications for management and conservation in the face of increasing fishing pressure on parrotfish. Moreover, conservation of Brazilian endemic parrotfishes requires protecting reefs with diverse attributes in order to conserve functional diversity.