Patterns of demersal fish distribution derived from line fishing experiment in Calauag Bay, Philippines

• Main Authors: Mamauag, Samuel S., Aliño, Porfirio M., Gonzales, Rhia Odessa M., Deocadez, Melchor R.
• Format: text
• Published: Animo Repository 2009
• Subjects: Groundfishes—Philippines—Calauag Bay; Epinephelus—Philippines—Calauag Bay; Coral reef fisheries—Philippines—Calauag Bay; Biology
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/11469
• Institution: De La Salle University

Long line experimental fishing was undertaken in 2005 to investigate patterns of distribution, catch composition, catch rate and size structure of demersal fishes at three coral reef sites with varying levels of fishing pressure in Calauag Bay, Philippines. Catch and size of most fishes were similar in the three sites, and catch rates were generally low, suggesting overfishing which probably occurred over a span of decades, hence, a homogenizing effect upon fishery variables. On the other hand, some fish showed variation in the patterns, and habitat correlates were found to be more influential than fishing. A distinct spatial pattern revealed an assemblage consisting predominantly of reef-associated fishes occurring at estuarine habitats. Ontogenetic habitat movement was shown especially for the orange-spotted grouper Epinephelus coioides, which demonstrated small individuals only at creeks and mangroves whereas larger and presumably reproductively active fish were observed distinctly at adjacent reefs. This is the first study that highlights the significance of the creek-mangrove-reef habitat continuum to the distribution of marine demersal fishes in the Philippines, with implications that existing management needs to incorporate non-reef habitat protection with fisheries stock enhancement schemes such as fry grow-out culture together with adult sanctuary and refugia measures.