TITLE:
Restoration of Stocks of the Sea Cucumber Holothuria fuscogilva in the Red Sea with Transplanted Wild Juveniles
AUTHORS:
Mohamed Hamza Hasan, Kelly S. Johnson
KEYWORDS:
Beche-de-Mer, Growth Rate, Gulf of Aqaba, Mortality, Restocking
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.11 No.8,
August
15,
2019
ABSTRACT: Over the last decade, holothuroid sea cucumbers in the Gulf of Aqaba of the Red Sea have been the target of continuous fishing. This has severely depleted sea cucumber stocks, especially the high-value species such as Holothuria fuscogilva. The present work demonstrates that restocking populations of H. fuscogilva that are at critically and chronically low levels by transplanting wild-captured juveniles can be effective. Juveniles were translocated from a robust population at Pharoan Island and released into two sites (Wadi Quny and Hidden Bay). Population density, growth rate and mortality at the original and two release sites were monitored for 2 yrs. The Pharoan population density was highest, with H. fuscogilva showing a strong preference for sandy habitat (21.3 - 18.4 ind./100m2), over seagrasses (3.6 - 2.5 ind./100m2) and corals (0.9 - 1.7 ind./100m2). The restocked population at Wadi Quny increased from 2.6 to 9.8 ind./100m2 from 2013-2015. In contrast, density at Hidden Bay decreased from 2.8 to only 0.1 ind./100m2 in the first year. Sea cucumbers in the restocked population at Wadi Quny had higher growth rates (0.65 - 1.29 cm/month) compared to the original population at Pharoan Island (0.21 - 0.45 cm/month), while Hidden Bay showed a negative growth rate. Mortality was low at Pharoan Island (1% - 2%) and Wadi Quny (0.5% - 0.75%), but high at Hidden Bay (49% - 100% in the first year). There was a negative relationship between mortality and size (P = 0.003). The restocking of H. fuscogilva populations using wild-captured juveniles was very successful at Wadi Quny but a failure at Hidden Bay.