Tridacna gigas (Cardiidae: Tridacninae) is the largest extant reef-associated bivalves that occur abundantly in the Indo-West Pacific Region. However, unregulated exploitation had caused localized extinction in many parts of its distribution range. In Palawan, the species was considered virtually extinct in the 1980s, and since then, no study has been done to monitor their status in the wild. In the absence of updated studies about T. gigas, we gathered information through field reports, key informants, and field visits. Within five months of data gathering, we recorded 97 empty shells (14 in pairs and 83 single shells) with 65.86 cm (range: 42-112 cm) average shell length, which were estimated to be from 5 to >76 years old. Most (78.36%) of the empty shells were used for decoration and landscaping. On the other hand, 29 live individuals with 73.69 cm (range: 42-109 cm) average shell length were estimated to be 5 to >76 years old. Tubbataha Reefs Natural Park and some island resorts harbored the highest number of live T. gigas. The presence of live T. gigas in these areas reflects years of effective management and the resorts’ essential contribution to resource conservation. These remaining live individuals could be used in breeding and restocking programs to restore their lost populations.
The attractive price for spiny lobster (Panulirus spp.) puerulus has recently encouraged many fishers to engage in its collection as an alternative livelihood at the height of the COVID-19 pandemic. This booming fishery prompted the investigation of the settlement traps, luring/shading materials, trap installation and harvesting methods, and problems encountered in the spiny lobster puerulus fishery in Palawan, Philippines. Reviewed videos posted on social media, personal observation, and data gathered from key informants (KIs) revealed the use of various modified and newly developed settlement traps. The most common were the concrete cylindrical and disc-shaped traps used by 63.33% of the KIs. Some KIs (40%) provided the settlement traps with luring/shading materials like Sargassum thalli. Settlement traps were mostly installed using the stake-hanging method. The harvesting season starts in March and ends in August where the daily collection coincides with the moon phase. Fishers collected settled puerulus through diving or pulling the traps out of the water. However, some issues like unstable prices and the absence of fishing regulations threaten the sustainability of pueruli collection. Hence, the establishment of collection zones, issuance of fishing permits, price regulation, and long-term monitoring to maintain this promising fishery industry is suggested in crafting ordinances. Efficiencies of traps may also be investigated as an additional basis for policy recommendations.
The farming of black-lip pearl oyster Pinctada margaritifera (Linnaeus, 1758) has been a viable industry for small and large-scale farmers in the South Pacific, but not in the Philippines, where it is monopolized by large-scale farms primarily based on the gold-lip pearl oyster Pinctada maxima. To promote the industry among small-scale players, we simplified the culture method by using bamboo slats as frame materials and compared them to the common material used in pearl oyster culture, metal rods. A total of 400 individuals seven-month-old hatchery-produced P. margaritifera were used as experimental animals, distributed in the following treatments with five replications: T1 (metal-framed pocket net basket with monthly cleaning), T2 (metal-framed pocket net basket without monthly cleaning), T3 (bamboo-framed pocket net basket with monthly cleaning), and T4 (bamboo-framed pocket net basket without monthly cleaning). Growth was fast in the first four months and slowed down after that. Two-way analysis of variance found no significant differences between the average anteroposterior shell (APS) length increments of pearl oysters between two types of frame, and between two cleaning conditions. Survival rates did not significantly differ between types of basket frame, and between cleaning conditions. Parameters of the “Typical” von Bertalanffy growth model (L∞ = 118.41 mm, K = 1.03 year-1, and t0 = 0.12) suggested that oyster would take about 23.16 months to reach 100 mm APS length, a size suitable for nucleus implantation. The life span of bamboo slats as basket frame was half of the metal frame, and the absence of cleaning has reduced the operational cost by up to 82.08%.
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