BATON ROUGE Animals incorporate a number of unique methods for detecting prey, but for the Japanese sea catfish, Plotosus japonicus, it is especially tricky given the dark murky waters where it resides.
John Caprio, George C. Kent Professor of Biological Sciences at LSU, and colleagues from Kagoshima University in Japan have identified that these fish are equipped with sensors that can locate prey by detecting slight changes in the water's pH level.
A paper, "Marine teleost locates live prey through pH sensing," detailing the work of Caprio and his research partners, will be published in the journal Science on Friday, June 6. This is the first report of any fish using pH to find live prey.
"What makes this so interesting is that the discovery was unexpected, quite serendipitous," Caprio said.
The study was an offshoot of work initiated in 1984 when Caprio, a specialist in aquatic vertebrate taste and smell systems, began a collaborative investigation at Kagoshima University examining the physiology of the taste system of the Japanese sea catfish. While performing electrical recordings from the fish barbells, or "whiskers," he noticed that every so often some new sensory nerve fibers would respond at a much larger amplitude than the others.
"Immediately I knew that there was something different about those nerves, but I was working on a different project funded by the National Science Foundation and had to put my curiosities on the back burner," Caprio said.
In 1986, Caprio's curiosities got the best of him, and he asked his friends in Japan to ship him some of the catfish so that he could examine what was triggering such huge responses in the fish.
"I suspected the response was due to a change in pH caused by some of the tested stimuli," he said. "It was obvious that there were sensory nerve fibers in these fish that were responding to transient lowering of the pH of the seawater
|Contact: Aaron Looney|
Louisiana State University