In the early 2000s, Brian Zimmerman and his team at London Zoo received a donation from a private fish-breeder, some Mangarahara cichlids. At the time, scientists hadn’t yet officially described the species. Not much was known about it, other than its provenance, the Mangarahara river in Madagascar. Little did Zimmerman know that within a decade he’d be putting up a ‘wanted’ poster in a last-ditch attempt to save the species from extinction.
Stopping extinction in its tracks
Zimmerman is Chief Curator at London Zoo’s aquarium and chairs an advisory group on fish and invertebrates for the European Association for Zoos and Aquaria. In 2011 and 2012, he ran a survey to find out what Malagasi fish from Madagascar were held at European zoos and aquariums. What species were there, how many animals of each species, and where were they housed? As a result of the survey, he discovered that there were only four Mangarahara cichlids in European institutions: two males under his care at London Zoo, and a pair (a male and a female) at Berlin Zoo. After some further checking, it became apparent that these were the only four Mangarahara cichlids living in zoos anywhere in the world. Zimmerman suggested to his colleagues at Berlin Zoo that they try to get their pair to breed. The Berlin team set their fish up in a special tank, away from visitors’ eyes, but the outcome was not what they’d hoped.
Like most cichlids, Mangarahara cichlids can be quite aggressive during courtship. Males and females will lock jaws and chase each other. This boisterous courtship can be energy-draining, especially for the females. Drab and brown, they are three to four times smaller than the whitish-silvery males, which have long flowing fins tinged with red, and faces that Zimmerman describes as “a little like gargoyles”. In Berlin, the courtship got so aggressive that the male ended up killing the female. The known captive population was down to three males.
Zimmerman and colleagues had been talking to specialists in the field, and a worrying picture was emerging: these three males might be the last of their kind. The Mangaraha river, where the species was originally from, was probably no longer able to support any of these fish.
Mass media to the rescue
With no fish to be found in zoos, Zimmerman contacted the people who had originally donated the Mangarahara cichlids to London Zoo, but they no longer had the species – nor did any other hobbyists that Zimmerman could find. It seemed likely that Zimmerman might watch a species go extinct. “I had a chat with our press team and said, ‘how can we raise awareness of this, because I’m really worried that we’re gonna lose this species, and that’s going to be the end of it; London Zoo is gonna be yet again the last place where a species is found before it became extinct’”, Zimmerman recalls. The team decided to put out an appeal, to try to see if there was any hope for the species, in the form of a female in a private enthusiast’s tank. The ZSL press team created a ‘wanted’ poster, calling for a female to join their two lonely males. “It was playful, to appeal to the general public – and it did!”, says Zimmerman. BBC World Service picked up on the story, and emails started pouring in from all over the world. Unfortunately, many were just messages of encouragement, and many others turned out to be dead ends. Then an email came in from a Malagasi businessman who said he thought he knew of a place where the fish still lived in the wild. He sent a map and a grainy photo. “It was the best lead we had at the time”, says Zimmerman. The place the businessman pointed to was near where the species had originally been found, on a tributary of the Mangarahara river. Zimmerman and the other specialists decided it was worth investigating.
In November 2013, Zimmerman put together a team and went on a month-long expedition to Madagascar. Their aim was to find out if the species was indeed still living in the wild, how healthy it was, and develop a conservation management plan.
“We tried to survey all the locations in the area where the fish may have existed, and we just kept getting dead ends”, says Zimmerman. “Either there were non-native species like tilapia that had outcompeted the cichlids, or there were just no fish at all, or the rivers were dry.” Then their Malagasi contact took them to the place where he believed the fish still lived. It was near a little village called Maratandrano. There, even in the dry season, the Ambobo river – a tributary to the Mangarahara – still had some water left, albeit in temporary pools. When the scientists got there, fishermen from the village had set traps, and they caught Mangarahara cichlids on the first day. The trip had been worth it, the species was not extinct! But it was also not thriving.
The Ambobo’s source is in a protected area, where the forest is still intact. That protection is probably why it can still support the Mangarahara cichlids. But the pools where the fish live are outside the protected area. Faced with threats like the river becoming uninhabitable or drying up, or non-native fish – which are often bred in community pools to feed local people – decimating the native species., Zimmerman and colleagues decided to set up a safety net for the Mangarahara cichlid and other native fish it shares the Ambobo with. The businessman that had alerted them to the species’ existence owns aquaculture tanks, where he breeds carp to sell in his restaurants. He offered some of them as safe havens for these native fish. So the scientists captured Mangarahara cichlids and three other species of fish, and drove them several hours North, to the tanks. Throughout the process, they trained local students in capturing and caring for the fish, too.
Caring for cichlids
There are now thousands of Mangarahara cichlids in those tanks, and some have even been taken to Toronto Zoo, where they’ve been successfully bred. ZSL and other organisations continue to provide financial and logistical support to the aquaculture, and Zimmerman and his colleagues are working on ways to improve conditions in the fishes’ native habitat.
They are considering setting up community pools with local species, so that people can have the food source without running the risk of escaped fish decimating local ecosystems. “Something that I’m particularly interested in a feasibility study is looking at whether or not we can do an assisted migration […] effort to basically move some of the fish from the area where we’re finding them in the Ambobo upstream into the boundaries of the Maratandrano Special Reserve”, says Zimmerman. But to do so, scientists need to learn a lot more about both habitats, and about the species. Some of that knowledge is already coming from the fish in the tanks in Madagascar. When they visited the site in 2016, Zimmerman and colleagues were able to observe and film the cichlids during spawning season. They discovered that unlike many other species of cichlid, in Mangarahara cichlids only the females appear to guard the eggs and the young. “They’re very territorial”, says Zimmerman, “and we’ve discovered that they each need about two square metres of rocky bottom.” This is valuable information, as it helps scientists calculate how many fish can live in a given area. “We couldn’t get that information in the wild, because river is too silty to film in”, Zimmerman points out.
Back in London, the two lonely males never did get a mate. But when they died of old age, the species didn’t die with them.
References
- Zoological Society of London News. “Worldwide fish appeal successful” https://www.zsl.org/zsl-london-zoo/news/worldwide-fish-appeal-successful (accessed January 2018).
- Zimmerman, B. 2014. “In search of the Mangarahara cichlid”, Newsletter of the IUCN SSC/WI Freshwater Fish Specialist Group, Issue 4, pp 17-22. http://www.iucnffsg.org/wp-content/uploads/2013/05/FFSG-Newsletter-March-2014-Small.pdf#page=17 (accessed January 2018).
About the author
Once upon a time, Sonia Furtado Neves was a two-year-old staring transfixed at a documentary on polar bears for the better part of an hour. Now, she gets a thrill from helping people see how weird and wonderful life is. A bilingual biologist turned science communicator, Sonia worked in Lisbon Zoo’s education department and then in the communications department at the European Molecular Biology Laboratory (EMBL). She is currently communications officer at the Portuguese Society for the Study of Birds (SPEA). Although she can’t draw to save her life, Sonia once made Edvard Munch’s The Scream out of pancakes.
