Enhancing the Recovery of Depleted Tripneustes gratilla Stocks Through Grow-Out Culture and Restocking

Abstract

Grow-out culture in sea cages and restocking were undertaken to help rebuild the spawning population of Tripneustes gratilla in Bolinao, Philippines. Higher population densities and incidence of recruits in [2004][2005][2006], as well as steady increase in the catch per unit effort of gatherers, indicate that the sea urchin population is recovering. Growth of reseeded, hatcheryproduced sea urchins in two sites was high and comparable to those in grow-out cages. However, natural mortalities were very high (91-99%). Good growth, high survivorship, and potential reproductive output of sea urchins in grow-out cages, aside from immediate socio-economic benefits, demonstrate that grow-out culture is a cost effective option for reestablishing effective spawning populations. Higher recruitment success in Lucero, compared to other sites, may be attributed to local favorable biophysical conditions and to maintenance of an effective spawning population due to enforcement of marine sanctuary rules, size regulation, and the presence of broodstock cages. Results suggest that the establishment of a network of marine protected areas in tandem with grow-out culture may be strategic in enhancing the recovery of depleted populations by maintaining larval exchange to sustain the productivity of sea urchin fishery stocks along NW Luzon.

Population genetics of the collector urchin, Tripneustes gratilla, in the Indonesian archipelago

“…It is commercially exploited as a food source throughout South‐East Asia and the Coral Triangle (Kasim, ). While the number of T. gratilla harvested from Indonesian waters is unknown, T. gratilla has been identified as the most important commercially harvested urchin species in the adjacent Philippines fishery, where collection was a half million US$ industry before unregulated harvesting caused collapse in 1992 (Junio‐Meñez, Bangi, Malay, & Pastor, ). The high commercial value of T. gratilla has spurred research into aquaculture programs designed to support commercial exports and the recovery of wild stocks (Dworjanyn, Pirozzi, & Wenshan, ; Junio‐Meñez et al, ).…”

Do Cues Matter? Highly Inductive Settlement Cues Don't Ensure High Post-Settlement Survival in Sea Urchin Aquaculture

“…T. gratilla is a quick growing species [17], [36] with a high market value. It is being targeted as an aquaculture species [8], [17], [37] and is produced in small quantities for restocking in Japan [1], [8] and as food in the Philippines [37]. Its broad feeding preferences mark it as a promising species for integrated aquaculture (Seymour et al, unpublished manuscript) and it is being studied as a biological control for invasive macroalgae in the Hawaiian Islands.…”

Extrinsic and intrinsic factors affecting the metamorphic rate of Tripneustes gratilla (Echinodermata: Echinoidea)

“…Because of this, the use of inducers to enhance settlement and metamorphosis has been investigated in the development of culture protocols for this species (Dworjanyn & Pirozzi 2008). Likewise, studies on settlement and metamorphosis of this species could provide insights on factors affecting benthic recruitment (Juinio-Meñez et al 2008a).…”