Newly hatched juvenile Buccinum undatum can be reared under laboratory conditions. Good growth was achieved when juveniles were fed on combined diets (blue mussel, cod, and fish pellets). Juveniles reached shell heights of 33.0 AE 4.2 mm, 26.9 AE 3.8 mm, 23.2 AE 2.2 mm, and 20.1 AE 1.6 mm, after 14 months of feeding on a combined diet, blue mussel, cod, and fish pellets, respectively under ambient sea temperature and salinity. After 14 months juveniles fed blue mussel had the highest survival rates (67%) followed by those fed a combination of all other experimental diets (61%), cod waste (53%) and fish-feed pellets (46%). High mortalities were recorded in most treatments during the summer months, between June and September. This species appears to have an aquaculture potential, as juveniles readily feed on artificial diets at an early age, show high survival rates and could potentially reach market size in 2 years or less. The major constraint in realising this potential at present, is the relatively low value of the species; if market values increased as a result of serious depletion of natural populations, hatchery production of juveniles for intensive aquaculture or restocking could become economically viable.

Life-history theory predicts an optimal offspring size, irrespective of reproductive effort; however, in some species offspring size correlates positively with maternal size. We examine hypotheses for why this latter situation should occur in the whelk Buccinum undatum. The trade-offs between aspects of reproduction in whelks are complicated due to the provision of protective egg capsules. Many eggs are placed within each capsule but c. 99% of these eggs are consumed by the remaining developing young. Large maternal size results in more eggs, larger eggs, more eggs consumed per hatchling, more capsules, larger capsules, more eggs per capsule, a larger number of hatchlings per capsule and larger hatchlings. Increased intracapsule and post-hatch sibling competition may decrease the marginal value for additional young and select for larger young, however, our data do not support this explanation. Instead, packaging constraints within each capsule limit the size of hatchlings but this constraint is relaxed for medium to large females because they produce large capsules. Small females appear to produce young below optimum size because of the space constraint thus explaining the correlation between maternal size and offspring size.

Newly hatched juvenile Buccinum undatum can be reared under laboratory conditions. Good growth was achieved when juveniles were fed on combined diets (blue mussel, cod, and fish pellets). Juveniles reached shell heights of 33.0 AE 4.2 mm, 26.9 AE 3.8 mm, 23.2 AE 2.2 mm, and 20.1 AE 1.6 mm, after 14 months of feeding on a combined diet, blue mussel, cod, and fish pellets, respectively under ambient sea temperature and salinity. After 14 months juveniles fed blue mussel had the highest survival rates (67%) followed by those fed a combination of all other experimental diets (61%), cod waste (53%) and fish-feed pellets (46%). High mortalities were recorded in most treatments during the summer months, between June and September. This species appears to have an aquaculture potential, as juveniles readily feed on artificial diets at an early age, show high survival rates and could potentially reach market size in 2 years or less. The major constraint in realising this potential at present, is the relatively low value of the species; if market values increased as a result of serious depletion of natural populations, hatchery production of juveniles for intensive aquaculture or restocking could become economically viable.

The survey was conducted in March 2021. The purpose of this survey was to analyze the structure of the mangrove community at Batang Masang Beach Nagari Tiku V Jorong Tanjung Mutiara District Agam Regency West Sumatra. The method used in this study is a survey method. In the mangrove area of ??Batang Masang, 3 observation stations have been determined. Each observation station was drawn by 3 transects over 50 m drawn from the mangrove boundary of the sea to the land. In each transect, 3 plots were placed, each plot consisting of 3 sizes, namely 10 x 10 m for the tree category, 5 x 5 m for the sapling category, and 2 x 2 m for the seedling category. The results of the survey revealed that there were 2 classes, namely the Magnoliopsida class and the Liliopsida class. In the Magnoliopsida class, there are 3 genera namely Acanthus, Rhizophora, and Sonneratia, and there are 3 species namely A. ilicifolius, R. apiculata and S. alba. In the class Liliopsida, there is only 1 genus, namely Nypa, and 1 species N. fruticans. Zone I is dominated by S. alba species, in zone II there are 2 dominant species, namely S. alba and R. Apiculata, and zone III is dominated by R.apiculata species. The criteria for mangrove vegetation are in the scarce criteria with densities ranging from 277.78 to 1066.67 ind/ha

ABSTRAKThis research was conducted at North Bintan island waters. The sample of sediment and snail S. canarium has been taken from four locations those were Busung, Lobam, Sebung, and Tanjung Bakau coastal waters. Analysis of metal concentrations both in sediment and snail conducted by using Atomic Absorption Spectrophotometer(AAS) Solar 969 AA. The result showed the highest concentration of Cadmium (Cd) and Cuprum (Cu) in sediment which were 0.51 ppm (Cd) and 13.22 ppm (Cu). While the highest concentration of these metals in snail S. Canarium wich were 0.56 ppm (Cd) and 8.42 (Cu), indicating that the concentration in both sediment and snail still below the normal threshold. It could be concluded that the Bintan Coast has not been polluted but lightly contaminated.