A new study says almost 40 percent of the fish species in North America's streams, rivers and lakes are in danger of disappearing. The study by the U.S. Geological Survey says there has been a huge increase in the number of endangered freshwater fish species since 1989, when the last study was done. Producer Zulima Palacio has more in this report narrated by Marissa Melton.  

The problems plaguing the earth's oceans -- pollution, declining saltwater fish stocks -- have been widely documented. But less is known about the conditions of lakes, rivers and streams and the freshwater fish that inhabit them. Until now.

Susan Haseltine is a biologist at the US Geological Survey, a government agency that studies the earth's conditions. "Over 700 species and sub-species are imperiled and that represents about 40 percent of our fresh water fish in North America," Haseltine said.

For the last 15-years, a group of scientists from the U.S., Canada and Mexico studied the habitat and population of fresh water fish in North America. The results -- published in the American Fisheries Society Magazine -- show that the main causes endangering freshwater fish are habitat loss, pollution, the growing number of invasive species and climate change.

Willie Kelly

Many fishermen in North America have noticed the changes. Willy Kelly has been fishing on the Potomac River and the Chesapeake Bay for more than 30 years. "The old days were much better than now. I have been here for three days in a row and got no fish," Kelly said.

The Director of the American Fisheries Society, Gus Rassam, says 61 species are extinct, hundreds are endangered and the list of those vulnerable is growing rapidly. "It is a catastrophe not just for fish obviously but for humans, because this is all one cycle. And when you reduce the biodiversity, you are affecting the human habitat as well," Rassam said. "So it is a catastrophic trend."  

Recreational fishing and related activities are a multi-million dollar industry in the United States. And it could be threatened by the decline in freshwater fish populations. Rassam warns that the growing number of endangered freshwater fish species in North America could be part of a wider worldwide trend.  

Gus Rassam

"When you look at the ocean fish, the trends are even more catastrophic, than have been published," Rassam said. "So it is unlikely that this does not exist in other countries and other continents. And we are talking here about a continental scale."

However, the Survey's study is limited to offering a detailed description of the problem and its causes. It does not suggest a plan of action.

"Well, we are a scientific organization so the best we can do is to present the data for policy makers and our fellow federal agencies to examine it and to use as part of their management decisions," Doug Beard said. He is with the U.S. Geological Survey.

He adds more scientists are becoming involved in programs to preserve fish habitats and to find scientific solutions to the problem. But he says the ultimate decision to take action rests on the local and national governments.