The declining natural population of Stichopus cf. horrens can be mitigated through the restocking of hatchery-produced juveniles. In this study, the use of shelters as part of a release strategy for this species was evaluated. Seventy-five juveniles (25.8 ± 0.1 g) were released in three experimental sites (ES) with shelters made of stacked dead coral heads. The juveniles were monitored for 60 d to estimate apparent survival, displacement, permanence, and disappearance rates, and to determine activity patterns and measure growth. On day 60, 42.7% (SD 19.7) of the juveniles were retrieved, which were equally distributed between the central and side shelters with a corresponding disappearance rate of −0.016 (SD 0.01) ind d −1 within a 50 m 2 area. The estimated displacement rate [0.03 (SD 0.03) m d −1 ] suggests that S . cf. horrens has a relatively small home range, thus may not need a large area to establish a spawning nucleus. During peak active hours, the juveniles were found outside the shelters or in the surrounding sand and seagrass blades. An average juvenile weight of 76.9 (SD 9.1) g was recorded upon termination, which was three-folds the initial weight suggesting that the juveniles were not food-limited. The low displacement rate, high growth, permanence rate, and apparent survival of juveniles in the ES indicate the potential of using dead coral heads as shelters in restocking cryptic species such as S . cf. horrens . Future studies on release optimization in terms of juvenile age/size, stocking density, time of release, and shelter design and placement are warranted.

Freshwater eels are emerging high-value species in aquaculture in the Philippines. However, the freshwater eel industry in the country remains under-documented, and most of the culture technologies employed are based on temperate eel culture. This study employed a mixed methods approach in primary and secondary data gathering. Key industry players across the value chain were identified and interviewed from February to October 2017 to gather baseline information on aquaculture practices, glass eel capture fisheries, and trading of anguillid eels. Secondary data from BFAR supplemented interview findings. Industry practices in 25 eel farms across the country were documented, the majority (80–85%) of which were nursery farms found in Regions 3 and 4A. There were five grow-out farms, with the largest production facility in Cabadbaran, Agusan del Norte. Different culture facility designs, glass eel stocking practices, water management, aeration systems, feeding schemes, and disease management were described. Most farms used concrete tanks with flow-through systems stocked at 500–1500 pcs/m2 and commercial feeds with binders, bloodworm, or trash fish as feeds. Four major glass eel collection sites were identified: Cagayan, the Davao region, General Santos-Sarangani, and Cotabato City-Maguindanao. The glass eel supply chain starts with collectors, followed by stockers and consolidators who consolidate glass eel catch prior to selling to growers or traders. After the desired eel size (6 inches) is achieved through culture, growers or traders sell the eels to exporters, local institutional markets, and local eel processing plants. The results of this study provide essential information that will pave the way for science-based research to improve the existing culture practices and fisheries policies that will help boost aquaculture production and guide proper management programs.

Periphytic diatoms constitute a major part of complex unicellular aggregations called marine biofilm or periphyton, of which little is known about in tropical marine environments. The early-stage community structure of periphytic diatom genera on two artificial substrates – glass slide and polycarbonate sheets – was characterized. These artificial substrates were placed underwater for 6 d and examined on Days 1, 3, and 6 in four sites around Santiago Island, Bolinao, Pangasinan, Philippines, with different relative distances from the intensive milkfish mariculture area. Correlations of diatom community structures in these sites with physico-chemical factors were investigated. The five most abundant diatom genera – namely, Cylindrotheca, Nitzschia, Navicula, Amphora, and Pleurosigma – exhibited a weak correlation with nutrients. Less abundant genera Pseudonitzschia, Haslea, Bacillaria, Thalassionema, Rhizosolenia, Eucampia, Diploneis, Asterionellopsis, Chaetoceros, Bacteriastrum, Licmophora, Skeletonema, Lioloma, Thalassiosira, and Thalassiothrix showed a positive correlation with nutrients. Among sites, the highest benthic diatom cell densities (4.6 × 105 cells cm−2) after 6 d was found in Lucero. Generic richness and diversity varied among sites, with the highest diversity (H’ = 1.58) on Day 1 in Tomasa, the site nearest to the mariculture area, whereas the highest richness (D = 2.17–3.26) for all days and diversity (H’ = 1.38–1.52) for Days 3 and 6 were recorded in Silaqui, the most distal site. Generally, the highest diversity and richness were found on Day 1, which then decreased on succeeding days in all sites. The lack of a clear pattern in community structure among sites relative to the proximity of these sites to the mariculture area may in part be attributed to the presence of other nutrient sources. Results of the study provide baseline information on the variability of periphytic diatom community structure in a mariculture-impacted area, and insights on how benthic diatoms may be used in monitoring the impacts of nutrient pollution.