By Jonathan L. Mayuga
An official of the Department of Environment and Natural Resources (DENR) on Wednesday warned hobbyists against releasing into the wild their imported pets, which may eventually threaten other native species.
Director Theresa Mundita Lim of the DENR’s Biodiversity Management Bureau (BMB) issued the warning
in light of the continuing knife fish infestation in Laguna de Bay, the country’s largest freshwater lake.
Lim said imported pets, such as ornamental or aquarium fish, crabs, turtles, spiders, lizards, rodents and snakes, are potential invasive alien species, and should be safely kept in tanks or cages by hobbyists.
She added that the Wildlife Conservation and Protection Act prohibits the introduction of invasive alien species into the wild because of their potential adverse impact to the natural ecosystems.
Lim warned that imported pets can easily survive and adapt to new environments and may eventually dominate other native species threatening the country’s rich biodiversity.
She said the BMB issues import permits for exotic animals as pets, but warned against unreported breeding or introduction into the wild.
These exotic wildlife are often smuggled into the country because the BMB is very strict in issuing import permits. According to Lim, the BMB makes sure that the pets are not invasive and can be easily controlled. She said the DENR-BMB studies reports of the behavior of pets, particularly feeding habit and reproduction to determine their potential danger, before issuing permits.
The proliferation of invasive alien species, she said, may affect the country’s food-production capacity, as well, citing its potential impact in forests and water bodies, such as lakes and rivers.
She cited the effect of the dreaded janitor fish and knife fish which have invaded the Laguna de Bay. The 90,000-hectare lake supplies 70 per cent of Metro Manila’s fish requirement. Fishermen, who go out to fish in the lake, complain that instead of native fishes with high commercial value, they end up catching janitor or knife fish.
Both the janitor fish and knife fish are considered a serious threat to the lake’s biodiversity as they compete with other native fish for food, prey on smaller fishes and feed on eggs while reproducing faster than any other species. Another aquarium pet, the Chinese soft-shell turtles have been reported to infest the lake and other inland waters, including fish ponds in Central Luzon.
Introduced in the Philippines as an aquarium fish to naturally clean aquariums, the janitor fish once became a major headache to small fishermen after they started to proliferate in the Laguna de Bay. After the janitor fish, the Laguna de Bay is now threatened by the dreaded knife fish, an ornamental species, which has the appearance of the famed arowana.
The Laguna Lake Development Authority and the Bureau of Fisheries and Aquatic Resources (BFAR) of the Department of Agriculture (DA) are planning to address the knife fish infestation in the lake by electrocuting its eggs in fish pens.
Fish-pen operators and other stakeholders will be consulted about the implementation of the plan as electrocuting the eggs of the knife fish may also kill eggs of other fish species present in the target areas.
“We are appealing to pet lovers to be very cautious. Accidentally or intentionally releasing their pets into the wild pose serious threat to our biodiversity,” Lim added.
The official said these pets may compete with other native species for food or become predators of other species. Invasive alien species, she said, easily reproduce, thus, by sheer number, can cause ecosystem imbalance.
“The problem is when these invasive alien species have completely replaced other native species. Every species have an important ecological function, and once they are replaced by these invasive alien species, getting rid of them will require deeper study,” said Lim, citing the case of the tilapia, which is now more famous than the native galunggong because it is cheaper and can be bought in the market all year-round.
Tilapia was introduced in the Philippines as early as the 1950s for aquaculture production. The Mozambique tilapia (Oreochromis mossambicus), which came from Thailand, has dark color and smaller in size than the Nile tilapia, which was introduced in the 1970s. Today, being a major source of protein, tilapia is still being promoted for aquaculture, and the DA-BFAR is introducing these fish in inland waters to boost fish supply.
However, because of the tilapia’s proliferation in rivers and other water bodies, many native fish have become extinct. “We now have fewer fish to choose from. Puro tilapia na lang,” she said.
“That is the problem with invasive alien species, you get fewer choice for food,” she added.
Lim said that because of reports of the invasion of the janitor fish and lately, the knife fish in the Laguna de Bay and its impact to the livelihood of small fishermen, the BMB is now very cautious in issuing import permits for all other exotic pets.
She said pet lovers should also secure a permit from the BMB before breeding.“They should let us know if they are into breeding, so that we can monitor these potential invasive alien species,” Lim said.
The BMB is also monitoring the Burmese python. A potential invasive alien species that can render other native snakes in the wild extinct. Pythons are popular among a unique group of pet lovers with fascination for large reptiles.