There's been a noticeable decline in the supply of tawilis over the past 10 years. Photo from the DENR-Biodiversity Management Bureau website.

Miss tawilis? The study to keep the only freshwater sardine in the world alive is showing promise

This is a significant development in tawilis research, since this is the first time the fish has been successfully collected, transported and reared alive away from its natural environment, says DOST head Fortunato de la Peña  
ANCX Staff | Mar 11 2021

You’ve perhaps wondered why you rarely see the tawilis in your palengke or grocery trips in recent years. This sardine species, which we love to consume either deep-fried or pinangat, has actually been classified as endangered for years now.

Sardinella tawilis is endemic only to the Taal Lake—meaning, it can’t be found anywhere else in the country and the world. It’s also the only sardine species known to survive entirely in freshwater. Unfortunately, it has been included in the “red list” of threatened species published in 2018 by the International Union for Conservation of Nature (IUCN), an international organization advocating nature conservation and sustainable use of natural resources.

The Taal Volcano Crater Lake. Photo from the DENR-Biodiversity Management Bureau website.

The Switzerland-based group noted in its report that the population of the fish species has declined by at least 50% over the past 10 years, which qualifies it as endangered. Filipino scientists who probed the case attributed the steady decline of its population to “overfishing, illegal use of active fishing gears such as motorized push net and ring net, proliferation of fish cages, and deterioration of water quality.”

Being on that red list had since sparked concern among conservationists. It also urged the government to start enforcing a closed season for tawilis in the entire Taal Lake—from March to April every year—to allow the endemic fish species to reproduce. 

The phreatic eruption of the Taal Volcano in January 2020 likewise got our Filipino scientists worried over the possible decimation of the freshwater sardine, supposing another volcanic event happens.

So this year, the Department of Science and Technology–Philippine Council for Agriculture and Aquatic Resource Research and Development (DOST-PCAARRD) through the University of the Philippines Los Baños-Limnological Station (UPLB-LS) embarked on a mission to keep the tawilis alive.

The conservation research, which involved rearing the fish off site or away from its natural location, has been a success, reported DOST Secretary Fortunato T. de la Peña in an article published by the Manila Bulletin.

Crispy Tawilis at Taaleña. Photo by ABS-CBN News

In a Facebook post by the UPLB-LS, it was mentioned that one of the major hindrances to this study is the sensitivity of the species to collection and transport methods. But they were obviously able to fine-tune the system, and the team headed by Dr. Ma. Vivian C. Camacho has successfully kept the tawilis alive for several weeks in captivity at UPLB-LS in Los Baños, Laguna, away from Taal Lake.

Here’s a little trivia about the only freshwater sardine in the world. In an interview with Philstar, Rey Donne Papa, a limnologist who is also dean of the University of Santo Tomas College of Science, said the Taal Lake used to be connected to the Balayan Bay. But the volcanic activities in the 18th century as well as the unique geological characteristics of the lake have led to the evolution of the species. And that was how the tawilis said to have adapted to the desalinated waters of Taal Lake.