Saturday, November 22, 2014

Cichlids of Laguna de Apoyo by Willem Heijns

People are always asking what is to see in Laguna de Apoyo during a SCUBA dive. Lots of folks have Open Water certifications these days, but most of them have only dived in tropical oceans, over coral reefs where brightly colored fish dazzle. Tropical coral reefs are indeed among the best eye candy on the planet. But people are intrigued when they learn that we SCUBA dive in tropical lakes when the ocean is so close. It's obvious to them that something very attractive must be going on down there to keep our attention, with coral reefs just a couple of hours away.

We at FUNDECI/GAIA study the fish in this lake and in other freshwater locations in Nicaragua. Lake Apoyo has clear, warm water (28 degrees C) which makes it easy to view the fish underwater. Our divers have been collecting data on the fishes of Lake Apoyo for years, learning about the differences between very recently evolved species and even documenting the species themselves. Over the years, other research groups have also become interested in the cichlid fishes of Lake Apoyo and neighboring lakes, especially the group headed by Axel Meyer of the University of Konstanz.


The fish of the Midas cichlid group are definitely the main attraction in Laguna de Apoyo. Since the lake was formed some 23,000 years ago, the lake has been colonized by a few species of fish, but the dearth of species in the lake has left numerous, broad niches available for specialization in feeding, refuge behavior, and nesting activity. The Midas cichlids in the lake have undergone a remarkable evolution, dividing into numerous species. Six species from this group which are only found in Laguna de Apoyo are now accepted in the scientific community. Publications which present these six species can be found here, here, and here. These cichlids are terribly similar, but they do not interbreed, and they even use different timing and locations for nesting in the lake

The video presented above, produced by Willem Heijns, is among the best quality of videos showing some of these species in their natural habitat. We hope you enjoy seeing this video. Thank you, Willem!

Laguna de Apoyo

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Willem Heijns
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