Population structure and reproduction of brittle stars species on different biological substrates

Abstract

The class Ophiuroidea is an abundant group in marine communities. It is commonly associated to other organisms due to individuals cryptic behavior, which makes them less visible. This is partly responsible for the lack of knowledge of many aspects of the biology of the group. The association between the animals and different substrates, such as sponges and algae, is advantageous since it can offer refuge against predators and adverse environmental conditions, food availability, thus suitable location for development of associated fauna. We intend to study and compare aspects of population biology related to size-frequency distribution and reproduction of common species of brittle stars associated with biological substrates: Ophiactis savignyi with the sponge Mycale angulosa and O. savignyi, Ophiactis lymani and Amphipholis squamata with the algae Caulerpa racemosa. The individuals will be identified to species level, counted and analyzed for the possibility of regeneration. Sponges were collected every 3 months at São Sebastião channel, North coast of São Paulo state, from May 2011 to March 2012. Algae were collected at Fortaleza beach, in Ubatuba, from August 2004 to June 2005. The brittle stars will have their disks measured for analysis of population structure and regeneration. Their arms will be counted and measured, thus the individuals will be divided into three categories (recently split, regenerating, and intact)and related to assimetry of disc to verify possible occurence of regeneration as indicative of asexual reproduction.(AU)