05 January 2013

The Nopili Rock-Climbing Goby And How It Climbs and Feeds

Gobies (family Gobiidae) have the most members in its family of fish. There are about 2000 species of gobies.

Mudskippers are part of the family. These fish stand out as they can crawl on land using their fins as legs. Despite this, they still have to return to water from time to time to keep their gills and fins moist.

The Nopili rock-climbing goby is also another species of gobies that has a peculiar trait. These fish can climb up rocks (usually up waterfalls). And as researchers have recently studied, using their mouths.

The Nopoli can be found in the islands of Hawaii, these fish live in mountain streams. Although as young juveniles, they start off on saltwater (the eggs are washed off into the sea where they hatch). As they mature, they make their way into freshwater streams. They feed off algae on the surface of rocks and gravel. They are also known as Oopu Nopili and Stimpson's goby.

Climbing Waterfalls

Going against the flow is always a challenge, but some waterfall-climbing fish have adapted to their extreme lifestyle by using the same set of muscles for both climbing and eating, according to research published January 4 in the open access journal PLOS ONE by Richard Blob and colleagues from Clemson University.

Video: Rock climbing goby

The Nopili rock-climbing goby is known to inch its way up waterfalls as tall as 100 meters by using a combination of two suckers; one of these is an oral sucker also used for feeding on algae. In this study, the researchers filmed jaw muscle movement in these fish while climbing and eating, and found that the overall movements were similar during both activities. The researchers note that it is difficult to determine whether feeding movements were adapted for climbing, or vice versa with the current data, but the similarities are consistent with the idea that these fish have learned to use the same muscles to meet two very different needs of their unique lifestyle.

"We found it fascinating that this extreme behavior of these fish, climbing waterfalls with their mouth, might have been coopted through evolution from a more basic behavior like feeding. The first step in testing this was to measure whether the two behaviors really were as similar as they looked" says Blob, lead author on the study.


Public Library of Science
Clemson University
US National Science foundation
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