Fishery Resource Enhancement: An Overview of the Current Situation and Issues in the Southeast Asian Region

The total global production from capture fisheries has plateaued since the mid 90s. This stagnation in production or reduced productivity of the world's coastal and marine wild fisheries is caused by overfishing and degradation of habitats through coastal development and destructive fishing methods. Reports have shown that if the current fishing trends continue, all of the commercial fisheries will have collapsed by 2050. To boost production, scientists, fisheries managers, government agencies, and NGOs have been looking at ways of enhancing fish stocks. Replenishing depleted stocks may be done by regulating fishing effort, restoring degraded nursery and spawning habitats or through resource enhancement. Resource enhancement using individuals reared in aquaculture facilities or seed stocks abundant in the wild is becoming a popular method of supplementing depleted stocks. It is one of the many strategies that could help address the decreasing fisheries production in the wild. A brief history of resource enhancement, the aquatic species released in the different countries in the region, the reasons for releasing stocks, and the issues involved, are discussed briefly in this paper. Among the main reasons for resource enhancement are to increase production or enhance stocks and increase food supply and/or family income. Other reasons include protection of endemic and maintenance of endangered species, rehabilitation of degraded natural habitats and for recreation fisheries, among others. Age or size of seeds, seed quality, genetics, governance, economics, biodiversity conservation, politics, and the introduction of exotics are among the resource enhancement issues identified in the region

SEAFDEC/AQD stock enhancement initiatives: release strategies

The Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) started its Stock Enhancement Program more than a decade ago with the first stock enhancement initiative on the mud crab Scylla spp. funded by the European Commission. This was followed by another stock enhancement program in 2005 supported by the Government of Japan Trust Fund. In preparation for its implementation, a Regional Technical Consultation on Stock Enhancement of Species Under International Concern was convened in Iloilo City, Philippines in July 2005 to identify species for stock enhancement. During the meeting, seahorses Hippocampus spp., giant clam Tridacna gigas, abalone Haliotis asinina, and sea cucumbers Holothuria spp. were among the priority species for stock enhancement work. Stock enhancement, restocking and ranching are management approaches involving the release of wild or hatchery-bred organisms to enhance, conserve or restore fisheries. This paper reports SEAFDEC/AQD release activities and some of the release strategies that have been established for mud crabs, giant clams and abalone

Philippine Aquatic Wildlife Rescue and Response Manual Series: Marine Turtles

This manual addresses the lack of information materials on how to deal with marine turtle encounters in the Philippine seas to ensure that the proper treatment and intervention is provided. The manual also responds to the Comprehensive Action Plan for Threatened, Charismatic, and Migratory Species of the Sulu-Sulawesi Marine Ecoregion (SSME), which has been identified as the first priority seascape the Coral Triangle Initiative (CTI). The Tri-National Committee of the SSME developed the Comprehensive Action Plans (CAP) that identified seven Key Result Areas (KRAs) to improve the status of marine turtles in the SSME, as follows: (a) Identify best practices in minimizing threats to marine turtle populations and their habitats; (b) Develop and implement nesting habitats and management programs to maximize hatchling production and survival; (c) Provide recommendations on specific features or criteria in marine protected area (MPA) design and MPA network design in relation to the protection and management of marine turtles in SSME waters; (d) Undertake initiatives to promote reduction of incidental capture and mortality of marine turtles; (e) Conduct turtle population habitat research and monitoring protocols; (f) Develop guidelines for MPA network design for marine turtles; and (g) Publish information to promote best practices and successes for marine turtle conservation. This manual is an important step to address gaps and issues on threatened marine wildlife in the Philippines to better protect and conserve marine biodiversity in the Coral Triangle.The publication of this book is made possible through the collaboration of the Department of Environment and Natural Resources-Biodiversity Management Bureau (DENR-BMB), Marine Wildlife Watch of the Philippines (MWWP), and the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) through its Adaptation to Climate Change in Coastal Areas Project (ACCCoast). This project is part of the Internationale Klimaschutzinitiative (IKI). The German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) supports this initiative on the basis of a decision adopted by the German Bundestag (http://www.international-climate-initiative.com)

Fishery resource enhancement: An overview of the current situation and issues in the southeast Asian region

The total global production from capture fisheries has plateaued since the mid 90s. This stagnation in production or reduced productivity of the world’s coastal and marine wild fisheries is caused by overfishing and degradation of habitats through coastal development and destructive fishing methods. Reports have shown that if the current fishing trends continue, all of the commercial fisheries will have collapsed by 2050. To boost production, scientists, fisheries managers, government agencies, and NGOs have been looking at ways of enhancing fish stocks. Replenishing depleted stocks may be done by regulating fishing effort, restoring degraded nursery and spawning habitats or through resource enhancement. Resource enhancement using individuals reared in aquaculture facilities or seed stocks abundant in the wild is becoming a popular method of supplementing depleted stocks. It is one of the many strategies that could help address the decreasing fisheries production in the wild. A brief history of resource enhancement, the aquatic species released in the different countries in the region, the reasons for releasing stocks, and the issues involved, are discussed briefly in this paper. Among the main reasons for resource enhancement are to increase production or enhance stocks and increase food supply and/or family income. Other reasons include protection of endemic and maintenance of endangered species, rehabilitation of degraded natural habitats and for recreation fisheries, among others. Age or size of seeds, seed quality, genetics, governance, economics, biodiversity conservation, politics, and the introduction of exotics are among the resource enhancement issues identified in the region

The pawikan album: The sea turtles captured around Panay and Guimaras Islands, Philippines

SEAFDEC FishWorld worked with fishers and government officers to document 93 sea turtles captured by fishing gears along the coasts of Panay and Guimaras Islands, Philippines in 2000-2009: three leatherbacks Dermochelys coriacea (128-150 cm curved carapace length), two loggerheads Caretta caretta (77 cm), 18 olive ridleys Lepidochelys olivacea (47-69 cm), 18 hawksbills Eretmochelys imbricata (20-89 cm), and 52 green turtles Chelonia mydas (30-108 cm). Most green turtles were caught in near shore fish corrals, and most olive ridleys by gill nets and long lines. Of the 18 hawksbills, 2 adults were caught in fish corrals, 3 juveniles were entangled in nets in Iloilo Strait, 6 were pets off our people,and 7 were captives at a turtle feeding station near a known hawksbill nesting site in Lawi, Guimaras. Sixty documented turtles were released, 47 of them with monel or inconel tags of the Pawikan Conservation Project, Department of Environment and Natural Resources. The others died from entanglement, serious injuries, slaughter for market, and diseases. Six female green turtles had multiple fibropapillomas; two died, three were released, and the latest one healed well after the surgical removal of several large tumors and was released. One green turtle brought to FishWorld has advanced shell rot, is unable to submerge, but is doing well on a diet of red seaweed Gracilaria. Three pet hawksbills were retrained for life at sea; one was released after 17 months, another after 57 months, but one is still at FishWorld as Conservation Ambassador. The most important result of FishWorld's work in the past 10 years is that many captured sea turtles were checked for health condition, treated where necessary or possible, tagged, and released back to sea. In addition, data on 93 sea turtles were gathered that can be used in the continuing effort to monitor the locations, risks and threats, health and diseases, and movements of these endangered species

Level of L-ascorbyl-2-monophosphate-Mg as a Vitamin C Source in Practical Diets for the Asian sea bass, Lates calcarifer

The stable vitamin C derivative, L-ascorbyl-2-monophosphate-Mg (AMP), was used as a supplement in practical diets for Asian sea bass, Lates calcarifer. Optimum growth, liver ascorbic acid (AA) saturation, and wound healing were determined. Sea bass (78.9±0.4 g) were fed a maintenance diet without vitamin C supplement for 25 days, then distributed into fifteen 1500-l oval fiberglass tanks at 30 fish each and fed one of five practical diets containing 0, 50, 100, 200, or 400 AMP mg/kg diet for 14 weeks. Fish fed the AMP-free diet exhibited clinical signs of vitamin C deficiency and significantly poorer final average weight, specific growth rate, protein efficiency ratio, feed conversion ratio, and hematocrit level (p<0.05). The level of AA in the sea bass brain increased as the level of dietary AMP increased. The AA concentration in the liver was similar at all AMP dietary levels. Body calcium of sea bass fed the AMP-free or 50 mg diets was significantly lower (p<0.05) than in fish fed the other diets. AMP enhanced wound healing regardless of supplement level, but fish fed the highest dietary AMP (400 mg/kg diet) exhibited histopathological changes in the liver. The dietary level of 50 mg AMP/kg diet was adequate for optimum growth, liver AA saturation, and prevention of clinical signs of vitamin C deficiency in 80-220 g sea bass. However, 100 mg AMP per kg diet was necessary for optimum body calcium

The first record of a cupped oyster species Crassostrea dianbaiensis in the waters of Japan

With a combination of our mitochondrial and nuclear DNA data, we evidenced the occurrence of a Crassostrea oyster hitherto unrecognized in Japan. This species, C. dianbaiensis (named Sumizome-gaki in Japanese), was very recently described as a new “tropical” oyster, although we located it in a temperate water zone (southwestern coast of Shikoku Island, Japan). Our specimens bore a morphological resemblance to the slipper cupped oyster C. bilineata (syn. C. iredalei), consistent with their close phylogenetic relationship. Some of the shell characteristics represented in the original species description were not applicable to our specimens, especially in terms of the pattern of their inner-shell coloration. Our novel finding of C. dianbaiensis in Japan updated the taxon list of Japanese Crassostrea species

Enhancing mud crab population through mangrove restoration

Abstract only.Mangroves are known as important nurseries for different species of fish and shellfish. In the Philippines, mud crabs Scylla spp. are among the most valuable crustaceans harvested from the mangroves and are considered a delicacy. However, varying levels of overfishing have been reported in different parts of the country. The decrease in production may be due to increasing demand for the resource and the loss of mangrove habitat. This problem may be addressed through regulation of fishing effort, rehabilitation of habitats, mangrove-friendly aquaculture and enhancement of wild crab stocks. This study shows the effect of mangrove rehabilitation on mud crab population. From July 2010 to December 2011, a total of 2.166 tons of mud crabs (n=17,558) have been collected from a 66.5 ha abandoned pond that has been recolonized by mangroves. The catch was dominated by S. olivacea (79.96%), then S. tranquebarica (19.92%) and S. serrata (0.12%). Male to female ratio was at 1.09:1. Individual daily yield ranged from 0.06 to 8.4 kg while catch per unit effort in terms of quantity and biomass ranged 0.02-1.46 crab gear-1 day-1 and 1.1-213.54 g gear-1 day-1, respectively. The results showed that mud crab population in this study site was much higher than the population in the reforested (Walton et al., 2006, 2007) and natural mangroves (Lebata et al., 2007) with almost the same area. For 18 months of sampling (April 2002-September 2003), only 3,924 crabs were sampled in the natural mangroves while 10,504 in the reforested mangroves. Mud crab production in the present study site resulted in a yield of 21 kg ha-1 yr-1, 5 and 3 times higher than the yield reported in the natural and reforested mangrove areas, respectively. These results imply that habitat restoration can be very effective in restoring natural populations of mud crab

Evaluation of post-release behavior, recapture, and growth rates of hatchery-reared abalone Haliotis asinina released in Sagay Marine Reserve, Philippines

The lucrative returns brought by abalone fisheries have caused overexploitation and decline of the wild population. In the Philippines, the Aquaculture Department of the Southeast Asian Fisheries Development Center has successfully produced Haliotis asinina seeds in the hatchery. Aside from utilizing these seeds in aquaculture, they are also being considered for future stock enhancement endeavors of the department. This study aimed to evaluate post release behavior, recapture and growth rates of hatchery-reared abalone juveniles released in the Sagay Marine Reserve. From the two release trials conducted, results showed that abalone of shell length >3.0 cm had lower mortality during onsite acclimation and utilized transport modules as temporary shelter for a shorter period after release. Both wild and hatchery-reared abalone preferred dead branching corals with encrusting algae as their habitat. Recapture rates were comparable between the wild (7.97%) and hatchery-reared (HR2) abalone (6.47%). Monthly growth rates were almost the same between wild (0.25 cm, 4.0 g), hatchery-reared (HR1: 0.27 cm, 4.6 g; HR2: 0.35 cm, 3.8 g) abalone. Moreover, hatchery-reared abalone were recaptured up to 513 days post-release, indicating viability of released stocks in the wild. Results of releases revealed that hatchery-reared abalone can grow and survive with their wild conspecifics

SEAFDEC/AQD stock enhancement initiatives: Release strategies established

SEAFDEC/AQD's Stock Enhancement Program started in 2001 with the first stock enhancement initiative on mud crab Scylla spp. funded by the European Commission. This was followed by another stock enhancement program in 2005 supported by the Government of Japan Trust Fund with seahorses Hippocampus spp., giant clam Tridacna gigas, abalone Haliotis asinina, and sea cucumbers Holothuria spp. as priority species. This paper discusses the release strategies that have been established for giant clam, abalone and mud crab