Featured Research

from universities, journals, and other organizations

Study Assesses Impact Of Fish Stocking On Aquatic Insects

Date:
March 29, 2009
Source:
US Forest Service, Pacific Southwest Research Station
Summary:
The impact fish stocking has on aquatic insects in mountain lakes can be rapidly reversed by removing non-native trout, according to a new study.

The impact fish stocking has on aquatic insects in mountain lakes can be rapidly reversed by removing non-native trout, according to a study completed by U.S. Forest Service and University of California, Davis, scientists.

Their findings appear in a current online issue of the journal Freshwater Biology where they describe experiments that examined some effects of fisheries management practices now in use in California mountain lakes where fish do not naturally occur.

The research has value because the vast majority of mountain lakes in the western United States have been stocked with trout for several decades. Studies following lake restoration to fishless conditions will help scientists and wildlife managers understand the impact of past actions and future decisions.

Since 2000, the California Department of Fish and Game has reduced the number of wilderness lakes it stocks by about half because non-native fish feed on declining species like the Sierra Nevada yellow-legged frog. Federal and state agencies have also begun removing introduced trout in some lakes because fish can survive for years and continue feeding on sensitive species, after stocking has ceased.

Until now, scientists seldom studied the response of aquatic insect populations to the removal of non-native trout.

"These highly-mobile predators don't naturally occur in small alpine lakes so they have significant top-down effects on ecosystems," said Karen Pope, a Forest Service scientist at the Pacific Southwest Research Station and one of the study's authors. "They prey upon aquatic insects that are also food for other insects, amphibians, birds and bats."

In 2003, Pope and her colleagues began testing the effects introduced fish had on lake ecosystems in 16 lakes in Northern California's Trinity Alps Wilderness.

The National Science Foundation, U.S. Forest Service, California Department of Fish and Game, and University of California funded the study, which matched current California fisheries management practices by including lakes with continued stocking of trout, suspension of stocking and removal of all fish. It also included fish-free lakes as reference sites for the study.

The researchers used floating nets on each lake's surface to quantify aquatic insect populations. They also used gill nets to sample trout density at lakes where there was continued stocking or suspension of stocking.

Their results showed the presence of introduced trout was the most important factor affecting the emergence of insects from the lakes.

Aquatic insect populations quickly increased when trout were removed from lakes. However, the scientists found suspension of stocking was not effective for restoring insect abundance in most lakes. This was not surprising because suspension of stocking alone had little effect on trout density, according to the researchers.


Story Source:

The above story is based on materials provided by US Forest Service, Pacific Southwest Research Station. Note: Materials may be edited for content and length.


Journal Reference:

  1. Pope et al. Changes in aquatic insect emergence in response to whole-lake experimental manipulations of introduced trout. Freshwater Biology, 2008; DOI: 10.1111/j.1365-2427.2008.02145.x

Cite This Page:

US Forest Service, Pacific Southwest Research Station. "Study Assesses Impact Of Fish Stocking On Aquatic Insects." ScienceDaily. ScienceDaily, 29 March 2009. <www.sciencedaily.com/releases/2009/03/090326162749.htm>.
US Forest Service, Pacific Southwest Research Station. (2009, March 29). Study Assesses Impact Of Fish Stocking On Aquatic Insects. ScienceDaily. Retrieved April 21, 2014 from www.sciencedaily.com/releases/2009/03/090326162749.htm
US Forest Service, Pacific Southwest Research Station. "Study Assesses Impact Of Fish Stocking On Aquatic Insects." ScienceDaily. www.sciencedaily.com/releases/2009/03/090326162749.htm (accessed April 21, 2014).

Share This



More Plants & Animals News

Monday, April 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Breakfast Foods Are Getting Pricier

Breakfast Foods Are Getting Pricier

AP (Apr. 21, 2014) Breakfast is now being served with a side of sticker shock. The cost of morning staples like bacon, coffee and orange juice is on the rise because of global supply problems. (April 21) Video provided by AP
Powered by NewsLook.com
Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Newsy (Apr. 20, 2014) A 9-year-old Michigan boy was exploring a creek when he came across a 10,000-year-old tooth from a prehistoric mastodon. Video provided by Newsy
Powered by NewsLook.com
Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins