The effect of feeding four diatom diets (Amphora sp., Navicula ramosissima, Amphora sp. + N. ramosissima, and mixed diatoms) and two attachment substrates (PP+CCA: polyvinyl plates with crustose coralline algae; PP-CCA: polyvinyl plates without crustose coralline algae) were determined for seed production of abalone, Haliois asinina. On day 5, significantly higher number of larvae settled on PP+CCA fed with mixed diatoms followed by Amphora sp., N. ramosissima, Amphora sp. + N. ramosissima, and abalone larvae reared on PP-CCA fied with N. ramosissima only. Fewer larvae settled on PP-CCA fed with Amphora + N. ramosissima, Amphora sp. and mixed diatoms. The size of abalone juveniles from PP-CCA was significantly bigger compared with juveniles measured from PP+CCA. However, the number of juveniles harvested from tanks provided with PP+CCA was higher compared with tanks with PP-CCA. This study has shown that crustose coralline algae favored the settlement of H. asinina larvae and inoculation of diatom slurry is necessary to provide sufficient food for the growing larvae.

To evaluate the impact on biota of the release of arrow up million liters of bunker oil off Guimaras Island, Central Philippines, the penaeid shrimp populations in a protected island mangrove (Tandog) and a riverine mangrove (Sibunag) were surveyed by pocket seine 2-3 months after the August 2006 spill; results are compared to 1993 baseline data. A total of 529 individuals belonging to three penaeid species were collected - Metapenaeus anchistus in Tandog, and Metapenaeus ensis and Penaeus merguiensis in Sibunag. Shrimp densities were significantly higher in Tandog Island in 2006 compared to 1993 but remained similar in the riverine mangrove. This suggests that protection may have a greater impact than the Oil Spill per se because Tandog is part of the protected Taklong National Marine Reserve. In contrast to abundance, shrimp sizes (carapace length) were significantly smaller in 2006 compared to 1993 for both sites.

Increasing population, ineffective management, competition among fishing gears over access to resources and proliferation of destructive practices are imposing severe stress on the inland water bodies of Bangladesh. These factors also contribute to the increasing incidence of conflicts among fishery stakeholders. When unabated, these conflicts are potential threats to the livelihoods of millions of the poorest fishing communities that depend on these resources. Effective communication between conflicting parties is perceived as a key for establishing successful negotiations for managing conflicts. On this premise, this paper presents and assesses a Fisheries Conflicts Communication Framework, henceforth called FishCom, a tool for developing plans and strategies for managing fisheries conflicts in the inland fisheries of Bangladesh. This tool embodies a structured participatory process intended for use by policy-makers and conflict management practitioners. They have important roles in catalyzing and effecting changes that are instrumental in minimizing, if not totally eliminating conflicts. Experiences from applying FishCom in the inland fisheries study sites in Bangladesh show that it has enabled a systematic stakeholder-inclusive identification and evaluation of fisheries conflicts and planning of communication interventions to manage them.

Ranching, 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.

Natural processes tend to vary over time and space, as well as between species. The ecosystem services these natural processes provide are therefore also highly variable. It is often assumed that ecosystem services are provided linearly (unvaryingly, at a steady rate), but natural processes are characterized by thresholds and limiting functions. In this paper, we describe the variability observed in wave attenuation provided by marshes, mangroves, seagrasses, and coral reefs and therefore also in coastal protection. We calculate the economic consequences of assuming coastal protection to be linear. We suggest that, in order to refine ecosystem-based management practices, it is essential that natural variability and cumulative effects be considered in the valuation of ecosystem services.

This study explored the interdependencies of aquaculture markets in the Philippines by establishing price cointegration between wholesale and retail prices of three major species commonly farmed in the country, i.e., milkfish, tilapia and shrimp. The co-movements of wholesale prices between and among key markets for each species were also investigated. Moreover, exogeneity in prices was established using Granger-causation model to determine the existence of price leaders among these markets. Such information are crucial in farm management decisions of producers and traders through better understanding of the efficiency in price formation across production and consumption centers which in turn defines the movements in prices and products among markets. Appropriate policies for the development of markets for the three aquaculture species were also identified. Such policies are expected to contribute towards the attainment of efficient pricing and distribution of benefits among market players and stakeholders. These benefits are expected to manifest through the system of grading standards for fish traded in local markets and in the choice of cost-effective technologies in grow-out and post-production practices.

An enrichment experiment was performed to evaluate the changes in lipid and essential fatty acid contents of the rotifer Brachionus plicatilis fed with freeze-dried cells of tropical thraustochytrid Schizochytrium mangrovei (Isolate IAo-1). Rotifers starved for 24 h were fed with S. mangrovei cells at 200, 300, 400, 500, 600 and 700 mg L⁻¹. Enrichment was carried out at two periods (Short-term = 5 h; Long-term = 10 h) to determine the optimum time needed for the maximum enrichment of the rotifers. There was an overall significant increase in the total lipid, arachidonic acid (AA) and docosahexaenoic acid (DHA) contents of rotifers after feeding with freeze-dried S. mangrovei indicating the successful uptake of these nutrients in the rotifer's biochemical composition. On the other hand, docosapentaenoic acid (DPA) did not change significantly in enriched rotifers. Results of the present study indicate that both factors, feeding concentrations and enrichment periods, significantly affected the lipid, AA and DHA contents of rotifers. Uptakes of lipid, AA and DHA significantly increased with increasing feeding concentrations except for those fed the highest feeding concentration of 700 mg L⁻¹ for 10 h. Moreover, lipid and AA contents of enriched rotifers were significantly higher during the short-term enrichment period while DHA contents were significantly higher during the long-term enrichment period. Therefore, it is concluded that the feeding concentration of 700 mg L⁻¹ at an enrichment period of 5 h is optimum in the AA and DHA enrichment of rotifers. The strategic scheme of combining the proper amount of enrichment product and the duration of enrichment in boosting the DHA contents of rotifers will effectively ensure a reliable production of nutritionally superior rotifers at a minimal cost. This will ultimately contribute to the success of rearing marine fish larvae in the hatchery.

The black tiger shrimp (Penaeus monodon) is an ecologically and economically important penaeid species and is widely distributed in the Indo-Pacific region. Here we investigated the genetic diversity of P. monodon (n = 355) from eight geographical regions by genotyping at 10 microsatellite loci. The average observed heterozygosity at various loci ranged from 0.638 to 0.743, indicating a high level of genetic variability in this region. Significant departures from Hardy–Weinberg equilibrium caused by heterozygote deficiency were recorded for most loci and populations. Pairwise F_ST and R_ST values revealed genetic differentiation among the populations. Evidence from the assignment test showed that the populations in the West Indian Ocean were unique, whereas other populations examined were partially admixed. In addition, the non-metric multidimensional scaling analysis indicated the presence of three geographic groups in the Indo-Pacific region, i.e. the African populations, a population from western Thailand and the remaining populations as a whole. We also sequenced and analysed the mitochondrial control region (mtCR) in these shrimp stocks to determine whether the nuclear and mitochondrial genomes show a similar pattern of genetic differentiation. A total of 262 haplotypes were identified, and nucleotide divergence among haplotypes ranged from 0.2% to 16.3%. Haplotype diversity was high in all populations, with a range from 0.969 to 1. Phylogenetic analysis using the mtCR data revealed that the West Indian Ocean populations were genetically differentiated from the West Pacific populations, consistent with the microsatellite data. These results should have implications for aquaculture management and conservation of aquatic diversity.

Sediments from underneath fish cages and in mesocosm tanks were examined to establish indicators of diminished organic matter degradation potential of polychaete burrows from increased mariculture activities in Bolinao-Anda, Pangasinan, Philippines. Results showed that simple sediment characteristics may be used as sediment quality indicators to describe the contribution of burrows to biodegradable processes in sediments with extremely high deposition of organic particles. The indicators of diminished organic matter degradation potential of polychaete burrows are low redox potential (-113 to -150 mV for F. Spionidae and F. Eunicidae) at the 1 cm surface layer, absence or decreased size of burrow openings, presence of H sub(2)S, disappearance of apparent Redox Potential Discontinuity Layer (aRPD), formation of black sediment, and presence of Beggiatoa (sulfide oxidizing bacteria) and gas bubbles.

The use of levamisole as an alternative approach to disease prevention and control has been resorted to in aquaculture. Its immunomodulatory effect in several fish species is well documented but its effect on grouper, Epinephelus coioides requires further investigation. To determine its immunomodulatory effect on grouper, juveniles were injected and fed with levamisole. Intraperitoneal injection (IP) at 0 (control), 0.5, 5, 10, 20 and 50 mg levamisole/kg body weight was administered. Grouper were also fed diets containing 0 (control), 125, 250 and 500 mg levamisole/kg supplemental dry diet for 10 days. Hematocrit levels, total and differential leucocyte counts and bactericidal activity were examined 7 days post IP. Three, 5 and 7 weeks after last administration of supplemented feeds, growth and bactericidal activity werie checked. A significant (P<0.05) increase in the total leucocyte count was noted in the injection-treated fish. Granulocyte (19.39%) and monocyte (27.38%) percentages increased while lymphocyte(53.40%) population decreased in the differential leucocyte count. However, hematocrit levels were not affected by levamisole. Bactericidal activity against Vibrio anguillarum increased in treated (injected and supplemented) fish. A significant (P<0.05) increase in weight of juvenileswas observed 10 days after last feeding with supplemented diet. Groupers injected with 0.5 mg levamisole/kg body weight and those supplemented with 125 mg levamisole/kg dry diet exhibited the most significant (P<0.05) changes in parameters tested indicating immunostimulation. Growth (weight gain) and bactericidal activity peaked 5 weeks post administration of levamisole in the feeding experiment. Results of the present study strongly suggest that levamisole can enhance nonspecific defenses in grouper and opens the possibility of using immunostimulants in grouper culture.