FISH ARK Project for Taal Lake: Direction for Conservation of the Endemic Freshwater Fish Sardinella tawilis

The freshwater sardine Sardinella tawilis (Herre,1927) is endemic to Taal Lake, Batangas (Philippines) and is an important fishery species in the lake. Following declines in populations observed from fisheries landing data, S. tawilis was declared as Endangered in 2018 by the International Union for the Conservation of Nature (IUCN). The economic importance and conservation status of S. tawilis warrant a need for development of possible conservation measures that can be done during natural geologic and volcanic events, especially because Taal Volcano remains an active volcano. This study determined the possibility of ex situ captivity as a conservation measure for S. tawilis by developing appropriate collection, transport, and rearing protocols. A total of 10 collection, transport, and initial rearing trials for S. tawilis were conducted from July 2020 to May 2021. Beach seine-net with modifications was identified as the best method for collection of tawilis. Transport protocols which yielded the highest survival involved the use of 1000-l transport tanks with continuous aeration. Captivity trials showed that S. tawilis lasted ~27 hours in on-site ex situ housing, while approximately 28% of individuals survived after 30 days in off-site ex situ housing. This study presents the first successful attempt at rearing S. tawilis via off-site ex situ captivity. The protocols established by this project will need to be refined to explore possibilities of captive breeding or larval rearing.