Breeding and Larval Rearing of Asian Moon Scallop Amusium pleuronectes in Eastern Samar, Philippines

Abstract

Asian moon scallop, Amusium pleuronectes, is among the most common commercially harvested scallop in the Philippines. This study investigated suitable conditioning methods, induced spawning, and documented scallop larval development at the Marine Fisheries Research and Development Center (MFRDC) Guiuan, Eastern Samar. Scallops held in tanks with flow-through water system without substrate yielded high survival rate of 48.06 ± 5.95%. Optimum water temperature was 28-29°C for maintaining scallops. Isochrysis galbana and Chaetoceros calcitrans were suitable microalgal feed for A. pleuronectes consumed at 7,388,888 cells min-1 per scallop. These significant results were applied in maintaining scallops at the hatchery. As a result, scallops with an average 19.8 mm shell length (SL) reached 37.5 mm SL within four months with a survival rate of 96.57 ± 2.04%, average daily growth rate (ADGR) of 0.13 ± 0.04 mm.day-1, and specific growth rate (SGR) of 3.92 ± 1.31%.d-1. Natural spawning was successful under controlled conditions while induced spawning trial through thermal stimulation, food shock, sexual stimulation, and serotonin injection resulted unsuccessful release of sperm and eggs. The estimated number of fertilized eggs per spawning ranged from 0.22-1.4 million. Fertilized eggs appeared spherical and dark in color with 54.2-62.57 µm in diameter. After nine hours, the larvae developed into trochophore stage with 59.08-84.4 µm in length. D-veliger with 120.37-157.07µm shell length developed after 24 hours. Development of the early umbone stage was reached on day 5; and on day 7, the umbo larvae become well-developed with shell length of 135.45-173.36 µm. On day 9, pedi-veligers were observed in the culture. Spat grew 312.41-509.48 µm on day 16 and survived until four months with final shell length of 4-10 mm. For the larval rearing, stocking density of A. pleuronectes larvae observed highest survival rate of 0.04 ± 0.03% at 200 larvae/L, while no larvae survived at 800 larvae/L due to contamination of protozoans in the culture medium.

Molecular phylogenetic analysis of commercially important Asian monsoon scallop, Amusium pleuronectes (Linnaeus 1758) from Indonesia

“…Determining the phylogenetic status of an organism provides an important pool of information for biosecurity studies. A. pleuronectes is a species that provides important information on environment quality and plays a role in the food chain of marine ecosystems (Mahidol et al, 2007;Cabacaba et al, 2020). If the phylogeny of A. pleuronectes is fully clarified, basic information will be supplied to the studies to be carried out in order to protect the balance of marine ecosystems.…”

“…Asian monsoon scallop, Amusium pleuronectes, is a bivalve species which belongs to the Pectinidae. The species has very wide distribution from central Ryukyu Island, South China Sea to the South-East Asia, and Australia (Habe, 1964;Morton, 1980), at a depth of 18 to 40 m (Minchin, 2003) and temperatures ranging 28 to 29°C (Del Norte 1986;Cabacaba et al, 2020). A. pleuronectes lies recessed in the substrate, the white colored valve positioned lying on the seabed while brown colored valve is on top and the umbonal region is submerged in the substrate (Morton 1980).…”

Genetic structure of the commercially important Asian monsoon scallop, Amusium pleuronectes (Linnaeus 1758), across the Indonesian Archipelago

“…The Asian monsoon scallop is present in much of the Indo‐Pacific coastal area. The species has been recorded from central Ryukyu Island, South China Sea to South‐East Asia, and Australia (Habe, 1964; Morton, 1980), at a depth of 18–40 m (Minchin, 2003) and has a larval duration divided into five steps, which take 120 days to complete (Cabacaba et al., 2020). This species, though ecologically and economically important, often forms a major component of the catch of fishing vessels.…”