Animals We’ve Lost: The 15 Species of Carp That Have Disappeared from a Single Lake | Environment


IThey were a famous clan: a group of 17 species of carp found nowhere else in the world except for an ancient freshwater lake in the Philippines. One so fat it could be fried without oil, another sought after for its delicious egg-filled ovaries, a third known, oddly enough, for its endearing overbite.

Yet in recent years, 15 of them have been declared extinct, victims of mismanaged fishing efforts that accidentally introduced predatory fish into their habitat. In all likelihood, these invaders will continue to threaten native carp until none are left.

extinction obituary box

It is unclear how the carp ended up in Lake Lanao on the island of Mindanao in the first place. They likely swam up a waterway over a primitive land bridge to the now separate island of Borneo, which itself is teeming with carp. Once in the lake, they began to move in what has been described as an “explosive” way – and that’s kind of funny.

The fish known as bitungu (Barbodes truncatus), for example, was distinguished by its remarkably short lower jaw, which barely reached halfway to its upper counterpart. The result was a clearly visible overhang, like a diving board above a swimming pool. Whiskers framing his lips fell like foam noodles. Its “mouth appears to be open even when closed,” wrote one biologist.

The native inhabitants called Maranao, which means “the people of the lake”, were not too concerned about its appearance. Having built its traditions, culture and cuisine around Lake Lanao since at least the 13th century, this Muslim community knew bitungu in another form: food. Although the individuals are the size of an appetizer — about the length of an iPhone mini, at best — they could become the centerpiece of a good meal when fried, grilled, or baked en masse.

Map of the Philippines, highlighting Lake Lanao as a red dot to the south.

In the middle of the 20th century, major changes took place around the lake. The Philippines, which declared independence from the United States in 1946, had formed a Bureau of Fisheries that began supplying the country’s lakes with non-native species like milkfish and tilapia in the early 1940s. 1960s and 1970s, according to marine biologist Armi Torres. Unfortunately, these nascent aquaculture efforts were prone to stowaways. Larger omnivores like the snakehead gudgeon and reservoir goby, which spawned year-round and had a taste for carp, hitched a ride with the fish stock and set foot in Lake Lanao.

“The Bureau of Fisheries meant well because their goal was to try to feed Filipinos, but they had no idea how quickly biodiversity could collapse,” said Gregg Yan, director of Best Alternatives. , a group based in the Philippines that works to mitigate the damage caused by invasive fish. The construction of hydroelectric dams near the lake, the adoption of dynamite fishing and increased pollution have only accelerated the demise of the ecosystem.

From the start 1970 to 1991, surveys of local fish markets near Lake Lanao showed more invasive species for sale – and far fewer native fish. The bitungu was last seen in 1973. The International Union for Conservation of Nature declared it off in 2020, with other clan members.

The memory of the bitungu is rapidly fading and the relics anchoring its existence to this world have dwindled. “It’s sad to say that the name bitungu is only known to a few [elderly] locals,” says Onaya Labe, an assistant professor of biology at Mindanao State University, “and they don’t know its meaning. A collection of preserved fish from Lake Lanao, including bitungu, was largely destroyed in 1945when Japanese troops bombed the country’s Bureau of Science.

The only remaining image of the bitungu from a 1924 issue of the Philippine Journal of Science. Photograph: The Philippine Journal of Science

The only remaining image of the bitungu is a black and white illustration of a male fish from a 1924 manuscript. It could have been the shimmering color of topaz, or perhaps a warmer hue of amber, with a belly and pale fins. His species could have laid eggs once a year, or several. Although it is assumed that it preferred the warm, shallow waters of the lake, an evolutionary quirk may have prompted it to venture into the depths. We will probably never know.

The illustration captures an expression that a human observer might classify as perplexed, perplexed – or sad.


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