Observations on anchialine-pool shrimps (Decapoda: Caridea: Atyidae, Barbouriidae) from the Philippines: A re-assessment after four decades and discovery of a second epigeal pool

Abstract We document the current status of the enigmatic bright-red anchialine shrimps in Tiniguiban Islet in the western Visayas region of the Philippines. A second epigeal anchialine pool was discovered in nearby Hinlaran Islet, and two shrimp species were recorded in the pools, the large barbouriid Parhippolyte uveaeBorradaile, 1900 as previously reported and a much smaller atyid Antecaridina lauensis (Edmondson, 1935). The shrimps move in and out of the pools with tidal fluctuations, since both pools completely dry out at low tide. The shrimps remain very abundant in Tiniguiban despite extensive modifications made by its owners and an apparent decrease in dissolved oxygen levels. Magico-religious beliefs regarding these unusual red shrimps persist, yet a subtle shift in values is noted, particularly with the growing popularity of the Tiniguiban pool with local tourists. Further modernization and coastal development may rapidly threaten these rare shrimp populations. Our study provides baseline data for systematic study and future protection of these rare pools and their shrimps that uniquely dwell at the interface of cave and marine habitats.