Fish habitats in a small, human-impacted Sibunag mangrove creek (Guimaras, Philippines): a basis for mangrove resource enhancement
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The fish assemblage of a small, open access mangrove creek highly influenced by aquaculture farms, was studied for the first time in the Philippines as a baseline of such system as well as examining the degree of ecological disturbance among fish habitats, as basis for the necessity to rehabilitate mangrove resources aiming to balance human activities and mangrove functioning. In total, 475 fishes (total weight = 3875 g) were captured and 50 species representing 32 families were identified. Thirty two species were represented by small numbers (< 5 individuals). Commercial species was considerably high (~23 species) but majority were low grade commercial species. Total species, species diversity and fish abundance consistently showed a decreasing pattern from outside creek to inner creek. Fish habitats exhibited substantial differences following a distinct spatial segregation of fish communities, a dominance of non-shared species and a minimal species overlapping inside the creek, which is attributable to the existing mangrove fragmentation associated with aquaculture ponds in the area. Increasing levels of disturbances were observed within the creek indicating ‘stress’ as a result of overutilization of mangroves by aquaculture farms. Our results confirmed the need to rehabilitate mangrove resources in this area. The development of mangrove resources through reforestation, coupled by strict regulation of fishing activities and aquaculture ponds will reduce ecological stress in the area and regain gradually a robust mangrove functioning that will improve fish diversity, fisheries and productivity of adjacent coastal systems by creating a suitable fish nursery, feeding ground and refuge habitat.
CitationAbrogueña, J. B. R., Bagarinao, T. U., & Chícharo, L. (2012). Fish habitats in a small, human-impacted Sibunag mangrove creek (Guimaras, Philippines): a basis for mangrove resource enhancement.
Aquatic habitats; Fisheries; Animal populations; Aquaculture; Rivers; Mangrove swamps; Feeding; Abundance; Habitat; Ponds; Fishing; Species diversity; Commercial species; Mangroves; Biomass; Fish assemblage; Small mangrove creek; Disturbance; Aquaculture pond; Fragmented mangroves; Farms; Reforestation; Philippines
J.B.R. Abrogueña is grateful for the thesis grant given by the Erasmus Mundus Master of Science in Marine Biodiversity and Conservation (EMBC).
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Marine and Freshwater Research, 2009 - CSIRO PublishingRanching, stock enhancement and restocking are management approaches involving the release of wild or hatchery-bred organisms to enhance, conserve or restore fisheries. The present study, conducted from April 2002 to November 2005, evaluated the effectiveness of releasing wild and hatchery-reared (HR) mud crabs in the mangroves of Ibajay, Aklan, Philippines where preliminary studies demonstrated declining fishery yields, abundance and size of crabs. Comparison of survival and growth of wild-released and HR Scylla olivacea and HR Scylla serrata demonstrated the effect of nursery conditioning, size-at-release and species differences. Overall yield and catch per unit effort (CPUE) increased by 46% after stock enhancement trials. Recapture rates of released crabs were highest in wild-released S. olivacea and in crabs measuring 65.0–69.9 mm carapace width (CW) and lowest in non-conditioned HR S. serrata. Growth rates were highest for conditioned HR S. olivacea and lowest for conditioned HR S. serrata (11.7 and 3.7 mm month-1 respectively). Fishing mortality was highest for S. olivacea, whereas natural mortality was greater for S. serrata. Conditioning hatchery-bred animals before release is also important in obtaining higher survival. S. olivacea was the more appropriate of the two species for release in mangrove habitats inundated with low-salinity water. However, there is a need for site-specific studies to evaluate the effectiveness of releases.
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Baseline assessment of fisheries for three species of mud crabs (Scylla spp.) in the mangroves of Ibajay, Aklan, Philippines MJHL Lebata, L Le Vay, JH Primavera, ME Walton & JB Biñas -
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