| dc.description.abstract | Sea urchins (T. gratilla) is one of marine biota which has high economic value. Gonads of sea urchins usually call with “Roe”. Sea urchins roe can be used as a highly nutritious food. The sea urchins roe are a popular food and has very decent trade value, especially for the export of Japan, Korea, USA, Russia, Canada, Chile, Mexico, France, China. Utilization of sea urchin roe as food for coastal communities has longstanding in Lombok island. During the time period of the exploitation of sea urchin population without any caught control to save it sustainability. Over exploitation is one of the causes of declining populations of sea urchins in the wild. Therefore, the over fishing could be threaten the sustainability of sea urchins resource in the coastal of Lombok island. This research has four main objectives that include the following: (1) study about the spatial distribution of sea urchin (T. gratilla) and environmental factors that influence; (2) study about the population dynamics of sea urchin (T. gratilla), such as growth rate, mortality, gonadal maturation and spawning season, (3) determine the length at sexual maturation (Lm) and length of sea urchin T. gratilla that caught by fishermen, and (4) to analyze the status and the resource utilization level of sea urchin (T. gratilla). This result showed that 6 species of seagrasses has been found in Semerang Beach includes Cymodocea rotundata, Cymodocea serullata, Syringodium isoetifolium, Halophila ovalis, Halodule uninervis, and Thalassodendron ciliatum. Seagrass vegetation types in Semerang Beach is mixed vegetation (mixed seagrass beds) were generally dominated by C. rotundata, S. isoetifolium and H. ovalis. Densities of sea urchin T. gratilla ranging from 1,07 to 6,32 individual/100m2 with uneven distribution and related to the depth of water and seagrass cover. The Result of analysis showed that sea urchins T. gratilla is alometric negative growth (b<3), rated slowly growth and has small infinity length (D∞ = 92,4, K =0,780 dan to = - 0,084). Result also showed the total mortality value of sea urchins is 3,78 year-1 with low natural mortality (1,13 year-1) and high fisheries mortality (2,65 year-1). Based on thes value, estimated of exploitation rate (E) is 0,70 that indicate the overfishing condition. Spawning peak and recruitment occur on June (25% spawning stage). Size at sexual maturation is fairly large (58,2 mm) and achieved in a long time (1,2 years). Numbers of fishermen ranging from 5 – 16 persons with catch amount ranging from 569 – 1598 urchins/period. Harvesting intensity reached 52 urchins/person/hour and diameter of harvest sea urchins by fishermen ranging from 48,5 mm – 89,1 mm with 67,3 mm mean size. | en |
