Breeding Vulnerable Freshwater Fish
The ZSL Aquarium has a spectacular array of fish from habitats all over the world, but some of its most unassuming inhabitants are some of the most important. The ZSL runs breeding programmes for several freshwater fish species on the brink of extinction, or that are already extinct in the wild. You can see this critical breeding work in action when you visit ZSL London Zoo.
Though marine fish receive a large amount of attention for conservation work, the plight of freshwater fish is, if anything, more serious. Fish Net is a global consortium of organisations initiated by ZSL working to conserve freshwater fish species. The strategies include breeding programmes to protect the remaining individuals of the 385 critically endangered species, that will almost certainly go extinct without such action.
More about FishNet and threats to freshwater fish
Safety Nets for Species
The Aquarium at ZSL London Zoo is playing a major role in breeding projects for species in imminent danger of complete extinction, including the Corfu killifish and several Mexican species of pupfish and live-bearers.
The Corfu Killifish (Valencia letourneuxi) is one of the first species on which the Fish Net project has focussed. It used to inhabit a range in southern Albania and Western Greece, but has suffered a 50% decline in population over the past decade. Due to continued loss of habitat and competition from invasive species, it is projected to decline by 80% over the next decade. In 2005, ZSL teamed up with the Hellenic Centre for Marine Research Institute of Inland Waters in Greece, to conduct the first ever complete survey of the species’ range in Greece. On-going work includes a potential translocation of the species back into one of its former springs.
One of our Pupfish The ZSL’s is breeding four species of pupfish from Mexico. These fish live in small desert pools and can tolerate vast ranges of temperature, from nearly freezing to up to 40 degrees C as well as water salinities higher than seawater. Despite their hardy nature, of the pupfish species investigated by IUCN, 2 pupfish are Extinct, 3 Extinct in the Wild, and 12 Critically Endangered. This is due to their restricted habitats being drained for crops and invaded by alien species. The Chequered pupfish (Cualac tesselatus) is Endangered, Charco Palma pupfish, (Cyprinodon veronicae) is Critically Endangered, while the Potosi pupfish (Cyprinodon alvarezi) and the La Palma pupfish (Cyprinodon longidorsalis) are now Extinct in the Wild.
The Aquarium also breeds eight species of live-bearers or goodeids. They are heavily threatened by habitat loss and invasive species. The Butterfly goodeid, (Ameca splendens) and Golden skiffia (Skiffia francesae) are Extinct in the Wild and the Crescent zoe, (Zoogoneticus tequila)is Critically Endangered, so the ZSL breeding populations are crucial for these species existence.
Watch this video to see what Fish Net is doing to save La Palma Pupfish
Fish on Film:
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The Aquarium Behind the Scenes
Though a few of these scarce fish are on display in the Aquarium, there are several breeding rooms behind the scenes filled with tanks of these endangered species. You can see some of the breeding rooms through viewing panels inside the Aquarium, and see the tanks containing the various species we are breeding, as well as the aquarists feeding and cleaning the fish.
When eggs are laid and fertilized, aquarists remove them to be hatched out safely in separate tanks. The number of eggs that are produced each year by the breeding adults, which can be very variable: sometimes only a few eggs are produced, sometimes hundreds. Why they vary so much is not known, because we are still learning about the biology and reproduction of these species in captivity. Fish are separated in tanks by age, to prevent competition for younger fish from older fish. The populations of each species are also separated into two groups, in different rooms in case of accident or disease striking.
More about the Aquarium at ZSL London Zoo
Extending ZSL's Breeding Work
Breeding tanks in the Aquarium The ZSL has been building up breeding populations of these fish since small founder populations were collected many years ago. In fact, ZSL obtained the first six Butterfly goodeids in 1970. We hope to build up the captive populations to at least 200 adult individuals of each species. This would be a viable captive population that can be used to provide individuals for setting up breeding projects in other locations and hopefully, eventually for reintroductions.
The space in the Aquarium's breeding facility also limits the size of the captive populations and the number of species that can be bred. There are plans to develop a currently derelict part of the Aquarium to create a purpose built breeding facility, to ensure that the breeding groups are as healthy as possible and to extend the protection of a captive population to more vulnerable freshwater species.