In Sri Lanka, the hunt is on for alien fish in native lakes - Mongabay.com
In Sri Lanka, the hunt is on for alien fish in native lakes - Mongabay.com |
| In Sri Lanka, the hunt is on for alien fish in native lakes - Mongabay.com Posted: 06 Jul 2020 12:00 AM PDT
COLOMBO — Located in the suburbs of Sri Lanka's biggest city, Colombo, the picturesque Thalangama Lake is plagued by at least two invasive predatory fish species that are contributing to the decline of the native aquatic life. "I have heard villagers living close to the lake claiming that they had seen a fish with a long snout like an alligator in the Thalangama Lake waters," said Pathum Madhusanka, a young fish enthusiast who has made it his mission to rid the lake of the invasive species. The particular fish he's referring to is the alligator gar (Atractosteus spatula), native to North America and one of the largest fish from that region, which can grow to a length of 3 meters (10 feet). Madhusanka has for the past few years been painstakingly fishing out another species from the lake: the clown knifefish (Chitala ornata), also a voracious feeder, and native to Southeast Asia. He had to put his mission on hold when the Sri Lankan government imposed a lockdown in response to the COVID-19 pandemic. But within a day of the lockdown being lifted in May, Madhusanka was back at Thalangama with his rod and reel. And the first fish he hooked was an alligator gar, about a meter (3 feet) in length. "It seemed quite impossible to find an alligator gar in this water body," he told Mongabay.  There's growing interest among fish breeders in Sri Lanka to cultivate "monster fish" — exotic, large, often carnivorous species — and alligator gars have become a popular aquarium fish in many Sri Lankan commercial aquariums. "The owner of the alligator gar would have purchased it from a pet aquarium while it was small, but the fish would have soon outgrown the tank, making the owner release it into Thalangama Lake," Madhusanka said. Reports suggest there are at least three alligator gars in the lake; Madhusanka has to date caught two. He's also caught more than 70 knifefish in the five years he's been going after that species, widely recognized as one of the world's most invasive freshwater fish. Madhusanka discovered juvenile knifefish in Thalangama in 2017, indicating that they were breeding in the lake. Of the 97 species assessed for Sri Lanka's red list of threatened freshwater fishes, 61 are endemic to this Indian Ocean island. Of these, 12 are considered critically endangered, 29 endangered, and 10 vulnerable.  The list, compiled this year, recognizes alien invasive species as a big threat to the island's freshwater fish. It identifies 30 such introduced freshwater fish species in Sri Lanka's natural freshwater habitats. "However, not all the exotic fish released to the natural waterways can be listed as invasive," says Sampath Goonetillake, IUCN Sri Lanka's senior program officer for biodiversity. For a fish to be considered invasive, it must directly impact native species either by competing with them for resources or directly feeding on them. "We also have observed some other species such as gouramis, zebras, platy fish in natural waterways that are still not considered invasive, though it is extremely important to keep a watchful eye over them," Goonetillake said. Accidental and deliberate escapees The first recorded instance of exotic fish being introduced into natural bodies of water in Sri Lanka dates back to 1889. That's when the rainbow trout (Oncorhynchus mykiss), native to the northern Pacific region, was deliberately introduced to natural streams in Sri Lanka's central highlands for sports fishing. The next deliberate introduction was tilapia from Africa (Oreochromis mossambicus and Oreochromis niloticus), released in 1952 to boost aquaculture and inland fisheries. At first they were placed in man-made reservoirs, but soon spread far beyond, and are now found in many rivers and other natural water bodies. Suckermouth catfish (Hypostomus plecostomus), native to South America, and walking catfish (Clarias batrachus), from Southeast Asia, are also recognized as alien invasive freshwater fish in Sri Lanka, along with the clown knifefish, accidently introduced to natural systems by the ornamental fish trade in the 1990s. Common invasive species The suckermouth catfish, commonly known as "tank cleaners," are the most widely distributed and harmful invasive fish species found in Sri Lanka's freshwater habitats, according to Ramani Shirantha, a researcher on aquatic species with the National Aquatic Resources Research and Development Agency (NARA). "Suckermouth catfish lays more eggs than most other species," she told Mongabay. "And as the mother protects her eggs, their survival rate is about 80%, whereas the survival rate of native fishes is around 30%." This catfish is a hardy species able to survive several hours outside water and with fewer threats compared to native fish. This has allowed for its rapid expansion and ability to outcompete native species for food. Shirantha rated the knifefish as the second-worst aquatic invasive species, given that it directly feeds on the larvae of other species. The presence of invasive fish has become a serious ecological issue in Sri Lanka's natural water bodies, especially in the suburbs and island's dry zone, according to Shantha Jayaweera, a senior instructor with the aquatic group of the Young Zoologists' Association. Jayaweera has observed how Mayan cichlids (Mayaheros urophthalmus), native to Central America, have spread from another water body in Colombo to several other wetlands. "Mayan cichlids are known for their aggressive nature attacking other fishes. It will be a serious concern if not controlled immediately," Jayaweera told Mongabay. There's also the case of the guppy (Poecilia reticulata), native to the Caribbean region, and mosquitofish (Gambusia affinis), native to the Mississippi, which were introduced to feed on mosquito larvae. Both species are now established in many natural bodies of water, and research indicates that guppies have become more carnivorous, feeding also on amphibian eggs.  Guppies have even been found inside biodiversity-rich habitats in Sri Lanka's wet zone and montane central highlands, home to already threatened amphibian species found nowhere else on Earth. "During our freshwater fish survey, we found a guppy fish inside the Sinharaja Rainforest freshwater pool," said Madura de Silva, the president of the Wildlife Conservation Society Galle. "It is a mystery as to how guppies found their way into the forest regions, but this indicates that alien invasive fishes would pose a significant threat in the future." In light of their invasive nature, Sri Lanka banned imports of knifefish in 2003 and piranhas in 1998. But these fish continue to be locally bred, and accidental releases remain a risk. As a containment measure, the ban should be extended to cover the domestic aquarium fish trade, essentially prohibiting the cultivation of invasive species, said environmental lawyer and environmentalist Jagath Gunawardena. Gunawardena, who played a lead role in helping draft a bill to regulate alien species, said the continued introduction of such species, both flora and fauna, posed a serious threat to natural habitats. Banner image of a fully grown clown knifefish caught alive from a lake in urban Colombo, courtesy of Pathum Madhusanka. |
| Posted: 15 Jul 2020 11:22 AM PDT
Live streaming Siamese fighting fish Mutekimaru is hundreds of hours into his quest to be the very best. While some video games' success is limited to a specific demographic, Pokémon has an incredibly broad fanbase. The series is played by boys and girls, kids and adults…and now, even a fish. Mutekimaru (also known as Maurice) is a beautiful blue betta whose owner, Japanese YouTube user Mutekimaru Channel, recently posed the question of can a fish finish a Pokémon game? For this experiment, Mutekimaru Channel visually divided Mutekimaru's tank into nine different sections, each corresponding to a controller directional or button input (with the wrinkle that hovering over the section for the A/confirm button for three seconds counts as a second press). He then set up a camera to track Maruice's movements, and put together a circuit board that would relay the inputs to a GameCube running 2002's Pokémon Ruby (no emulation here!).
The owner gave Mutekimaru a tiny bit of help at the start, advancing the game's lines of introductory text. But once the game starts in earnest, the human turned things over to the fish, which happens at the 1:45 mark of the video above. Things get off to a pretty good start, too, as after just about a minute and a half Mutekimaru is able to move his no-screen Pokémon trainer out of the truck where the adventure begins.
 One of the first tasks for the player to perform is going to the main character's house and setting his clock. This takes Mutekimaru 35 minutes, which is still impressively speedy considering he's a fish and doesn't actually know he's playing a video game. But then things hit a major snag. Before you can venture out not the field and start catching Pocket Monsters, Pokémon Ruby makes you go to your neighbor's house and say hi to the kid who lives on the second floor. Completing this task takes Mutekimaru a whopping 19 hours and 10 minutes.
▼ The house with the arrow is the one he needs to go to.
 ▼ Yes!
 OK, now Mutekimaru can finally go out into the field. Unfortunately, there's only one exit out of town, a narrow opening at the north border, and it takes the fish a long time to stumble through it: 59 hours and 20 minutes! When he does, though, it's a wonderful sight to see.
 There's no time to waste celebrating, though, because this is where Pokémon Ruby has you choose your starter Pokémon by grabbing a Poké Ball from a bag and rescuing Professor Birch. Mutekimaru selects a Torchic, and then makes short work of a wild Poochyena, as seen here.
 ▼ Attacking with Scratch
 ▼ Victory!
 Of course, this also gives Mutekimaru the right to give his Torchic a nickname. ▼ He goes with "Nohohohoho."
 But though the betta is also known as the Siamese fighting fish, it turns out the Mutekimaru is far from aggressive in Pokémon battles. In addition to the condensed videos above, Mutekimaru Channel has also posted a number of multi-hour ones. At 60 hours and 11 minutes of playtime, Mutekimaru gets into his first random battle…
…in which he attack only once, and then runs away! ▼ "You successfully ran away!"
 This isn't a one-time thing, either. Mutekimaru almost immediately gets into another random battle, and again runs away before wandering back into town, and his pacifism continues even after he returns to the field and gets into more random battles. The problem seems to be related to the game's user interface. In order to attack, first the battle menu cursor has to be positioned over "Attack." From there, pressing the A button to confirm, brings up a list of available techniques, and hitting the A button again executes the attack, while hitting the B button cancels out and take you back to the main battle menu. On the other hand, if the cursor is positioned over "Run away," all you have to do to initiate the escape attempt is hit A once. In other words, attacking is a two-step process, but running away is only a single-step one. Factor in that defeating enemies usually takes multiple attacks, but successfully running away instantly ends the battle, and pure probability ensures that the majority of Mutekimaru's fights are going to end with him turning tail. And yet, Mutekimaru eventually gets the hang of fighting, and manages to capture an impressive variety of Pocket Monster species, including a three Zigzagoons, a Taillow, a Whismur, and a Nincada. ▼ Mutekimaru's battle triumphs
▼ Once again, his choice of nicknames is unique, like with this Zigzagoon that he named "A!!"
 You might have noticed that in the Pokémon-capturing montage, the layout of Mutekimaru's "controller" goes through some changes. That's because his owner noticed that the fish occasionally likes to concentrate on swimming in one part of his aquarium, which can lead to input loops that prevent him from making any progress. So occasionally his owner tinkers with the input assignments for different sections of the tank. Other impressive feats Mutekimaru has accomplished: evolving his Torchic into Combusken and defeating gym leaders to earn badges! ▼ Sure, it took him 373 hours and eight minutes to acquire the Stone Badge, but that's still less time than it would take us humans to learn how to breathe underwater.
▼ "Mutekimaru received the Stone Badge from Roxanne!"
 Mutekimaru has now logged over 676 hours playing Pokémon Ruby, earning two gym badges in the process, as well as a contingent of French fans in addition to his Japanese followers. ▼ Mutekimaru's current live stream
Oh, and if you like the idea of fish playing video games on Nintendo hardware, but you're not into Pokémon…
 …it looks like Super Smash Bros. is next on Mutekimaru's to-play list! Related: Mutekimaru YouTube channel, Twitter |
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