New hatchery technology to save endemic ‘ayungin’

Wild silver therapon caught in Laguna de Bay. Photo courtesy of FA Aya

By: Rossea H. Ledesma

The declining population of the native freshwater fish ayungin, also known as silver therapon,is set to get a boost after a scientist devised a newsystem of growing its larvae in captivity.

The hatchery technique was devised by Dr. Frolan A. Aya, a scientist of the Southeast Asian Fisheries Development Center, and granted a patent by the Intellectual Property Office of the Philippines (IPOPHIL) last Oct. 17, 2019.

Hatchery rearing of silver therapon larvae (inset) in outdoor tanks using pre-conditioned or aged rearing tank water at SEAFDEC/AQD’s Binangonan Freshwater Station in Binangonan, Rizal. Photo courtesy of FA Aya

“Silver therapon, locally known as ayungin, is regarded as one of the most valuable edible native freshwater species because of its tasty flesh. Despite the declining trend in wild stocks of silver therapon, demand for this food fish species remains high. It is sold from Php 200 to Php 800 per kilo when dried and around Php 500 per kilo when fresh depending on the season and catch,” said Dr. Aya.

The hatchery technology, just like other technologies developed by the Aquaculture Department (AQD) of SEAFDEC, will be for free and open to fish farmers interested to venture in ayungin culture.

Moreover, according to Dr. Aya, the hatchery protocol he developed can support the Philippine government’s “Balik Sigla sa Ilog at Lawa (BASIL)” program through the production of ayungin fry for stocking in Laguna de Bay to increase the wild population.

Information from the Philippine Statistics Authority reveal that ayungin catch in the country has declined from 4,765 metric tons in 2002 to only 1,408 metric tons in 2018.

Dr. Aya said that he will continue to do some refinements on the technology for seed production and rearing of ayungin and later demonstrate the technology to fisherfolk. Also, a manual on the biology and hatchery rearing of ayungin is already in the pipeline.

Hatchery rearing of silver therapon larvae (inset) in outdoor tanks using pre-conditioned or aged rearing tank water at SEAFDEC/AQD’s Binangonan Freshwater Station in Binangonan, Rizal. Photo courtesy of FA Aya

“It is also my plan to do the commercial production as well as the development of nursery and grow-out technology for this important fishery resource,” he added.

The patent, which was published in Volume 22 Number 124 of IPOPHL’s official gazette released on 20 November 2019, was made possible through the efforts of SEAFDEC/AQD’s Innovation and Technology Support Office headed by Dr. Roger Edward Mamauag.