music; ambience: river
Like many rivers, conditions on Alaska’s Kuparik river change from year to year. One year the water flow might be high, the next year low. The fish that live in the river have come to adapt to both situations. Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside.
“One of the things we’ve seen is that when conditions are very good for the adults, they tend to be very poor for the young.”
Heidi Golden is a research assistant to Linda Deegan at Alaska’s Toolik Lake Field Station. Over the years, they’ve been monitoring the Arctic Grayling, the only fish that lives in the Kuparik river.
“When the discharge is very high and the temperature’s low, the river then becomes broad again, and areas that were previously dry, then become the side habitats for the young of the year. And those areas don’t have the time to build up that nice diatom layer that feed the insects, so that habitat is a poorer habitat for the young of the year, and they just don’t feed as well, and they can’t get into the area where those good insects are.”
But when the discharge, the amount of water flowing through the river, gets lower then the newly hatched arctic grayling, the young of the year, do a lot better.
“When the discharge gets lower, and the current is less, then they can get down into areas where there’s a lot of good stuff to eat. So they do very well in those years. Fish have seemed to have a life history that fits perfectly with their environment. If you get a year where the adults are gonna do really bad, at least the young of the year are going to do really well. So you’re guaranteed to have somebody at some time doing really well.”
Understanding the changing populations of the Arctic Grayling can give scientists clues of the effects of climate change on the Alaskan Tundra. Our thanks to the Marine Biological Laboratory of Woods Hole.
Pulse of the Planet’s Science Diaries are made possible by the National Science Foundation.