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Subsistence and small-scale aquaculture are important economic and livelihood activities in developing countries including the Philippines. Community-based aquaculture of the sea cucumber (sandfish, Holothuria scabra) has been promoted as a sustainable supplemental livelihood activity among rural coastal communities, however, uptake remains poor and the economic viability of communal sea cucumber ranching has yet to be demonstrated. This study assessed the potential of sandfish farming as a supplemental economic activity for established small-scale grouper (Epinephelus coioides) farmers in Bolinao, northwestern Philippines, on the assumption that the adoption of sandfish culture may be more successful when attempted by established aquaculture farmers. The average growth rate of sea cucumbers reared in the pens without groupers was highest at 2.0 [+ or -] 0.4 g [day.sup.-1] during the first 50 days of rearing. By 141 days, sandfish reared without grouper attained an average weight of 234.7 [+ or -] 2.2 g. The highest growth rate of sandfish reared with groupers was recorded at 4.2 [+ or -] 1.8 g [day.sup.-1] after 19 days of rearing in the coculture pens whereas the lowest growth rate (-0.73 [+ or -] 0.1 g day- 1) was recorded by day 128. Additionally, the growth performance and survival of groupers reared with sandfish were high. From an initial average weight of 141.3 [+ or -] 35.2 g, groupers attained an average weight of 340 [+ or -] 27.8 g and 393.8 [+ or -] 17.8 g after 102 and 163 days of rearing, respectively in the grow-out pens. Farmers generated an estimated income of PHP 7,200 and PHP 29,015 from the sale of dried sea cucumbers and live groupers, respectively. Results indicate that the adoption rate, economic viability, and sustainability of sandfish mariculture may increase when technology is transferred to farmers already engaged in aquaculture. More broadly, the integration of sandfish culture with that of fish and other culture species, such as molluscs, utilizes the ability of sea cucumbers to remediate nutrientrich sediments, improving sustainability. KEY WORDS: Holothuria scabra, sea cucumber, sandfish, grouper, coculture, small- scale aquaculture, INTRODUCTION Aquaculture is the fastest-growing global food production sector achieving an annual growth rate of 5.3% between 2001 and 2018 and contributing one-third of global food fish production. Worldwide, 70%-80% [...]

Pearl culture in Fiji relies on a supply of pearl oysters obtained through the strategic deployment of spat collectors. Although the design and deployment of spat collectors aim to maximize the recruitment of pearl oysters (Pinctada and Pterin spp.), this activity incidentally captures many other bivalves as bycatch. This study explored whether tropical rock oysters (specifically Magallana bilineata and Saecostrea spp.) were present and sufficiently abundant as bycatch from pearl oyster spat collectors, to support additional commercial opportunities. The results showed that the absolute (0.7 [+ or -] 2.1 spat collector-1) and proportional (2.9% of all bivalves) abundance of these taxa was very low, which would limit oyster harvest in meaningful quantities. Although the prospect of creating additional revenue streams from bycatch could be seen as an incentive to on-grow and sell tropical rock oysters despite their low abundance, it is argued that greater benefit would come from prioritizing activities related to pearl oysters and associated downstream products such as mabe pearl, shellcraft, and pearl-meat production. Ultimately, existing spat collection activities within the cultured pearl sector did not have the anticipated potential to support supplemental aquaculture of tropical rock oysters. KEY WORDS: Fiji, spat collection, fouling, bycatch, tropical rock oyster, Saecostrea, Magallana bilineata, INTRODUCTION Tropical rock oysters are excellent candidates for aquaculture (Angell 1986, Nowland et al. 2020). They are consumed almost everywhere they occur (M unro 1994, Kinch et al. 2019a, Simard [...]

There is considerable interest in improving hatchery production of the mud crab, Scylla serrata. Although some progress has been made toward identifying appropriate feeding protocols for live-foods, the density at which food is first provided to larvae varies greatly in practice. This study examined relationships between rotifer density and activity patterns of enzymes critical to digestion in S. serrata to evaluate feeding protocols from a nutrient utilization perspective. Activities of trypsin-like proteases, nonspecific esterases, and [alpha]-amylase were quantified to determine the response of newly hatched (Zoea I) larvae of S. serrata to rotifers provided at four different densities (i.e., 10, 20,40, and [80mL.sup.-1]) from first-feeding. Results showed that rotifer density significantly (P < 0.01) influenced total activity (mU [larva.sup.-1]) patterns within 24h of first-feeding for all the enzymes assayed. Based on these patterns, utilization of the associated macronutrients (i.e., protein, lipid, and carbohydrate) was presumably similar when larvae were provided with rotifers at densities of 10, 20, or 40 [mL.sup.-1] and increased when larvae were provided with rotifers at a density of 80 [mL.sup.-1]. An optimal density at which to provide rotifers to S. serrata for first-feeding is likely to be >[40mL.sup.-1]. The comparative analyses of enzyme activities presented in this study represent an innovative approach to quickly (within 24 h) identify optimal food densities for larval crustaceans at first-feeding. KEY WORDS: Portunidae, Scylla serrata, mud crab, hatchery production, first-feeding, rotifers, enzyme activity patterns, INTRODUCTION Crabs of the genus Scylla, commonly referred to as mud crabs, have a complex life cycle, where larvae progress through five to six zoeal stages (3-5 days each) and [...]

Adductor muscle from Pinctada maxima and Pinctada margaritifera were analyzed for nutrient compositions. Both were characterized by relatively high-protein, low-lipid, and low-cholesterol contents. Palmitic acid and docosahexaenoic acid were the dominant saturated and polyunsaturated fatty acids, respectively, in both species. Amino acid compositions of adductor muscle from both species were characterized by a high abundance of glutamic acid, aspartic acid, and arginine, whereas cysteine, then tryptophan, were least abundant. Overall, these nutrient compositions are similar to those reported for other bivalve molluscs. The results are timely given the growing interest in pearl meat consumption and pearl meat farming. KEY WORDS: Pearl oyster meat, proximate composition, fatty acids, amino acids, aquaculture, Pinctada maxima, Pinctada margaritifera, INTRODUCTION Pearl oysters from the families Pteriidae and Margaritidae are harvested for food and used for cultured pearl production throughout the Indo-Pacific and Caribbean (Wada & Temkin 2008, Saucedo et [...]

There is considerable interest in developing hatchery techniques for the tropical spiny lobster, Panulirus ornatus. Although some progress has been made toward identifying effective foods and feeding protocols for this species, the density at which food is first provided to larvae varies greatly in practice. This study examined relationships between food density and the activities of major digestive enzymes in P. ornatus to evaluate larval feeding protocols from a nutrient utilization perspective. Specifically, activities of [alpha]-amylase. nonspecific esterase, and trypsin-like protease were quantified to determine the response of newly hatched larvae of P. ornatus to provision of Anemia nauplii at three different densities. Results showed that food density significantly (P < 0.01) influenced [alpha]-amylase and nonspecific esterase activities during the first 24 h of feeding, but had minimal effect (P [greater than or equal to] 0.09) on trypsin-like protease activities. Based on enzyme activities, there is no advantage to increasing food densities above 2.5 Anemia m[L.sup.-1], but when food density decreased to 0.5 Anemia m[L.sup.-1], the availability of dietary nutrients became limiting. An optimal density at which to provide Anemia nauplii to newly hatched larvae of P. ornatus is likely between 0.5 and 2.5 Anemia m[L.sup.-1]. The comparative analyses of enzyme activities presented in this study represents an innovative approach to identify potentially excessive or insufficient food densities quickly (within 24 h) for larval crustaceans. KEY WORDS: Panulirus ornatus. palinuridae. phyllosoma. hatchery, first-feeding, food ration, enzymology, INTRODUCTION There is considerable interest in developing reliable hatchery techniques for spiny lobsters (Palinuridae) driven by premium market value, high demand, and static or decreasing supply from wild-capture fisheries (Phillips [...]

The mass production of release‐size H. scabra juveniles in the Philippines is primarily done in a floating hapa ocean‐based nursery systems. To optimize its production, understanding the influence of different culture conditions and their management is necessary. In this study, the effects of hapa net cleaning interval, hapa layers, and stocking density on growth and survival of sandfish juveniles reared in floating hapa (L × W × H: 1.7 m × 0.9 m × 1.2 m) nursery system were assessed in two 60‐day field studies. Results showed that the number of hapa net layers and cleaning interval had negligible effects on the growth performance of sandfish juveniles by day 30. However, sandfish juvenile survival was affected by hapa net layers with higher survival in triple‐layer mosquito net hapas (40.5 ± 0.97%) compared to double‐layer mosquito net hapas (17.8 ± 0.62%). By day 60, the growth performance of sandfish juveniles in double‐layer hapas was higher (average weight: 5.0 ± 0.97 g; AGR: 0.13 ± 0.03 g day−1) compared to that in triple‐layer mosquito hapa nets (average weight: 3.1 ± 0.23 g; AGR: 0.07 ± 0.01 g day−1). Survival of sandfish juveniles reared in double‐layer mosquito net hapas, cleaned at 5‐day intervals (85.9 ± 4.58%) was significantly lower compared to all other treatments. Conversely, initial juvenile stocking density did not significantly affect the growth performance and survival of sandfish juveniles in both rearing cycles. We therefore recommend the use of triple‐layer mosquito net hapas during the first 30‐day culture period and an initial stocking density of 1000 post‐settled sandfish juveniles to increase production output. After 30 days, when the juveniles are larger, the use of double‐layer mosquito net hapas and lower stocking density are recommended to reduce cost and enhance growth performance. Where cleaning is necessary, hapa nets may be cleaned at 10‐day intervals to improve survival. The results of this study have important implications for optimizing the production of release‐size sandfish in ocean‐based nursery systems in the Philippines. [ABSTRACT FROM AUTHOR]

Expansion of pearl production using the silver‐lip pearl oyster, Pinctada maxima, depends on increasing the availability of high‐quality spat from hatcheries and optimization of existing hatchery protocols. Research to develop feeding regimes yielding higher quality spat is seen as a priority. This study evaluated the suitability of three microalgae (Rebecca salina, Chaetoceros simplex and Tisochrysis lutea), fed singly and in combination, for spat of P. maxima and assessed whether mixed diets yielded spat of higher quality. A model‐fitting approach examined the response of spat fed microalgal diets for 35 days. Organic content of spat, as an indicator of quality, as well as metrics relating to spat size and weight were considered. On the basis of organic content, all microalgal diets tested were found suitable and there was no evidence that the mixed diets yielded higher quality spat compared to monospecific diets. Further, any gains in spat size attributed to the mixed microalgal diets were comparatively modest. Contrary to long‐held assumptions, our results indicate that monospecific microalgal diets are not necessarily inferior to mixed microalgal diets for on‐growing spat of P. maxima. They indicate potential to develop simpler and cheaper protocols for culture of P. maxima spat in land‐based systems. [ABSTRACT FROM AUTHOR]

Crustaceans of the family Gonodactylidae (Order Stomatopoda) are potential predators of cultured pearl oysters in ocean-culture systems, yet they have not previously been implicated in contributing to on-farm mortality of culture stock. Improved knowledge of the threat posed by stomatopods to pearl oyster survival in ocean-culture systems, as well as possible influencing factors, is necessary to determine whether stomatopod predation merits concern and for prioritizing efforts to prevent and control predator incursions. The aims of this study were, therefore, to determine if the presence of stomatopods within culture units significantly affects cultured pearl oyster survival in an ocean-culture system, and whether predator or prey size exert influencing effects. Mortality of Akoya pearl oysters (Pinctada fucata) over a 6-wk culture period ranged from zero to 33.3% among individual culture units containing a single stomatopod (Gonodaciylaceus falcatus) at the study site in north Queensland, Australia. An interaction between stomatopod size and their time at liberty within culture units, as well as an interaction between stomatopod size and pearl oyster size, explained 84.1% of the variance in pearl oyster survival among culture units. Most prominently, small stomatopods (total length: 37.0 [+ or -] 0.9 mm) caused minimal mortality of culture stock (4.6% [+ or -] 1.1%), whereas large stomatopods (total length: 69.0 [+ or -]1.1 mm) had a significantly greater impact (20.8% [+ or -] 2.1% mortality) over the 6-wk period (P < 0.05). Given the potential for a single G.falcatus to cause up to 33.3% mortality of culture stock within a culture unit, the threat from stomatopod predation during ocean culture of pearl oysters could be significant and collection of site-specific information to assess this threat is recommended. KEY WORDS: Gonodaciylaceus falcatus, Pinctada fucata, Gonodactylidae, predation, pearl oyster, nursery culture, Australia, INTRODUCTION The Akoya pearl oyster, Pinctada fucata, has the broadest distribution of all commercially exploited pearl oysters (Wada & Temkin 2008), supporting cultured pearl production in Japan, China, Vietnam, India, [...]

Gastropods of the family Cymatiidae are a major predator of cultured pearl oysters, causing significant mortality in ocean culture systems. Improved knowledge of factors influencing cymatiid predation on pearl oysters is required to develop effective management strategies for these predators. This study determined whether size of the cymatiid, Gutturnium muricimim, is a significant factor influencing mortality of cultured Akoya pearl oysters (Pinctada fiicata), and whether predation by this cymatiid on bivalve species in an ocean culture system is nonrandom. A single G muricinum was capable of causing significant mortality in pearl oyster stock after a 6-wk culture period, with morality influenced by predator size. Oysters housed with a large (shell length: 55.0 [+ or -] 3.3 mm) G. muricinum experienced significantly greater mortality (23.3 [+ or -] 6.3%) than those in nets with a small (shell length: 37,8 [+ or -] 2.1 mm) individual (11.1 [+ or -] 0.6%). The presence of G. muricinum also had a significant impact on pearl oyster growth, but growth was not influenced by predator size. When presented with both Akoya pearl oysters and Hyotissa hyotis as potential prey items, cymatiid predation was nonrandom. Cymatiids preferentially preyed upon H. hyotis. that experienced 45.5 [+ or -] 12.4% mortality after 6 wk of ocean culture whereas, in the same nets, none of the Akoya pearl oysters were killed. Based on these results, various management strategies are discussed, and further research avenues identified. KEY WORDS: Gutturnium muricinum, Pinctadafucata, Cymatiidae, predation, pearl oysters, nursery culture, Australia, INTRODUCTION Pearl oysters (Family Pteriidae) generally require 2 y of growth in ocean culture systems before they are large enough for pearl production, and a further 2 y is required [...]

Shellcraft is a livelihood activity that utilizes shells and skeletal remains of marine taxa for producing ornamental and decorative items. Despite an increasing importance of shellcraft in coastal areas of the Indo-Pacific region, information necessary for stakeholders to identify and respond to change through policy and management decisions is often lacking for fisheries that support this activity. To address this knowledge gap, a quantitative approach was taken to evaluate social-ecological factors (the what, where, how much, who, when, how, how often, and how long) in a "shellcraft fishery" centered at the Nusa Islands of Papua New Guinea. More than 151,100 individuals across 69 marine taxa were fished annually for shellcraft at the Nusa Islands; fishing was infrequent and quantities fished were low for most taxa when compared with other small-scale fisheries. Fishing most taxa had no association with the main demographic divisions within households although, in terms of participation and catch richness, women were the main actors. Gleaning, combing, and free-diving were the only fishing techniques used, with taxa primarily fished by gleaning intertidal habitats during the day. To contextualize sustainability of this fishery, local ecological knowledge-based perceptions of stock status for the marine taxa fished were examined. Considerations for governance, which included synthesis of existing regulatory measures and aspirations, are also discussed. Since shellcraft occurs throughout the Indo-Pacific region and there are commonalities in taxa utilized, this study provides a basis for comparative analysis of shellcraft fisheries within the region. [ABSTRACT FROM AUTHOR]

Mabe pearl (half-pearl) culture provides rural livelihood opportunities in the South Pacific and is a low-tech alternative to capital and labor-intensive round pearl culture. The Kingdom of Tonga is unique among the pearl-producing countries of the South Pacific in focusing on mabe pearl culture using the winged pearl oyster Pteria penguin. The Tongan mabe pearl sector is developing rapidly and stimulated by routine supply of spat to mabe pearl farmers, from the government hatchery at no cost. It is likely that some level of cost recovery for spat supply will be considered as the sector strengthens, but information on hatchery production costs is limited. This study determined the costs of operating the government pearl oyster hatchery in Tonga and developed an economic model to assess the production cost of juvenile oysters. Modeling was based on a single annual hatchery run generating 6,600 oysters from the ocean-based nursery for delivery to commercial pearl farms. Estimated capital cost was USD 19,079 (excluding government buildings and chattels), and the major production costs were hatchery labor (37%), capital purchase and replacement (20%), and nursery labor (10%). Total annual costs for the pearl oyster hatchery were USD 13,263, equating to a cost of USD 2.01 per oyster supplied to farmers in Tonga. Given significant annual profits of around USD 9,338 that can be generated from 100 harvested oysters, there is justification for cost recovery. Results will be valuable to key stakeholders and have regional relevance for hatchery production of high-value aquaculture commodities. KEY WORDS: oyster hatchery, pearl culture, Pleria penguin, hatchery cost, INTRODUCTION Tonga, like many Pacific Island countries, has developed cultured pearl production to facilitate economic prosperity and enhance livelihood opportunities for coastal communities (Johnston et al. 2019a, Southgate et al. [...]

ABSTRACT This study assessed the use of novel, locally made, protective culture cylinders as a means of improving pearl oyster Pteria penguin performance and standardizing culture methods used by mabe [...]

Throughout the Pacific Islands, shellcraft has begun to feature prominently in development intervention which aims to generate positive livelihood outcomes for coastal communities. This activity often involves the post-harvest processing of natural assets, namely shells and skeletal remains of marine taxa, into jewellery by individuals or small-sized enterprises. To foster participation in shellcraft, development intervention commonly involves gifting or subsidising physical assets. Yet knowledge of the natural (i.e., taxa) and physical (i.e., tools) assets required for shellcraft remains scant. An understanding of human dimensions in shellcraft pertaining to patterns in asset use, such as how tool ownership differentiates taxa utilised and products produced, is important for determining if access to a specific tool is necessary, or an encumbrance, for achieving a desired outcome. In this study, we identified tools used and variation in tool ownership among artisans engaged in shellcraft to afford an accurate and realistic understanding of the tools required to participate in this activity. We then evaluate how ownership of a specific tool or type of tool differentiates both taxa utilisation and product production for shellcraft. Results indicate ownership of neither all nor any specific tool was required to participate in shellcraft, with artisans typically owning a unique combination of tools. Furthermore, results identified that some specific tools were critical for affecting the attractiveness of utilising certain taxa or producing certain products. Implications of the significant relationships between specific tools and certain taxa or products are discussed in the context of development intervention and commonly articulated theories of change where shellcraft is linked to subsistence fishing, aquaculture, or tourism. [ABSTRACT FROM AUTHOR]