"The most cost-effective way to minimize alien fish invasion is highly dependent on advance knowledge of invasion threats from information networks such as literature, Internet, and symposia," says Dr. Christine Marie Casal, Research Analyst of the World Fish Center during the Agriculture and Development Seminar Series (ADSS) last Dec. 4 at Drilon Hall, SEARCA.

The Vermiculated sailfin catfish (Pterygoplichthys
disjunctivus, locally known as“janitor fish”) is a known
alien invasive fish species in Laguna de Bay.
Source:www.fishbase.org

Alien fish species form the backbone of aquaculture and ornamental industries in the Southeast Asian region; but they also modify ecological interactions in the ecosystem. Alien invasive species also compete with or prey on indigenous species. However, the degree of impact is debatable, she further explained.

Ornamental fishery is the major pathway of entry for alien fish species but it is through aquaculture that they become established in the ecosystem. “The risk of invasiveness starts with the species’ establishment,” Dr. Casal said.

Another cause of alien fish species introduction is ballast water. Ballast water stabilizes ships and is a necessary feature of commercial shipping. It is composed of water and is filled with sediments, stones, and thousands of living species. Due to the high number of ports in the region, Southeast Asia is considered as a hotspot of alien fish species introduction due to ballast water.

The said lecture is the last ADSS for 2007. ADSS was launched in 2003 as a weekly scientific and policy forum. ADSS provides a venue for a dynamic and vibrant discussion of scientific findings, research results and perspectives within the purview of agriculture and development. It is held at SEARCA every Tuesday, 4-5 p.m., and is open to the public.