Population dynamics of three species of the genus Aplysina (Porifera, Demospongiae, Verongiida) in a tropical bay in the Western Atlantic Ocean

Sponges of the genus Aplysina Nardo, 1834 (Porifera, Demospongiae) can produce a large diversity of natural products of interest to industries such as the pharmaceutical trade. Here, we investigated the dynamics of population density, sponge size, and growth rate (GR) of three species of Aplysina over 25 months in a tropical bay on the Brazilian coast. We also analyzed how these characteristics are modulated by different environmental factors. We observed that A. solangeae was the most abundant species, followed by A. fulva and A. insularis . The dynamics of population density of A. solangeae and A. fulva could not be related to any of the environmental factors analyzed, but the population density of A. insularis was negatively related to photoperiod and rainfall. Specimens of A. solangeae were the smallest among the three species and presented a slow (negative) annual GR, and A. insularis was the species with largest size and fastest GR. Low tides were the main factor influencing the size dynamics of A. solangeae and A. fulva. The GR dynamics of A. solangeae was negatively modulated by chlorophyll-a and temperature, while the GR of the A. fulva population could be related to low tides. These important demographic data about these Aplysina spp. could be used for future management and conservation plans, especially if they are targeted for natural product discovery.