Assessment of Commercially Important Marine Invertebrates in Selected Areas of Anda, Pangasinan, Northern Philippines

Abstract

The status of commercial marine invertebrate resources was assessed in Anda, Pangasinan. A total of
ten species of sea cucumbers were recorded in Cabungan, Imbo, and Imondayon, of which two were commercially
important Stichopus horrens and Actinopyga echinites, and only one commercially important sea urchin Tripneustes
gratilla was found particularly in one site (Imondayon). Two high-value gastropods were observed, the abalone, Haliotis
asinina and top shell Trochus niloticus. Many other molluscs are found but considered low-value or non-commercial
species and gathered only for home consumption. Low densities of these commercial marine invertebrates were found in
the survey sites. Highest diversity index was observed in Imondayon with species diversity of H’=2.00, followed by
Cabungan and Imbo with H’=1.88 and 1.59 respectively. Based on interviews, the artisanal multi-species fishery is at
present primarily based on 3 sea cucumbers - Holothuria scabra, Stichopus horrens and Bohadschia marmorata, one sea
urchin, Tripneustes gratilla, and two gastropods, Haliotis asinina and Trochus niloticus, although there are indications that
other high-value species were fished to local extinction. The abalone fishery is observed to be overfished with densities of
1-2 individual per 250 m2. For sea cucumbers, the small sizes (<15 cm body length) observed in this study, their low
population densities, and the continuous decrease in catches are clear signs of an overexploited fishery that will likely
collapse without management intervention.