A recent article in the Concord Monitor reviewed a seminar co-led by a fishing guide and a biologist for the Maine Department of Inland Fisheries and Wildlife about the effects of smallmouth bass introductions on salmon and trout populations.  Bass can cause huge problems for trout and salmon by competing for food resources and preying on juvenile fish.  While bass fishing is a fast growing sport, salmon and trout populations will continue to shrink if we don’t take action concerning the problems with illegal fish introductions.

In what biologists believe is an event related to cold conditions on Lake Champlain, a major die-off of alewives was observed by anglers and the Vermont Department of Fish and Wildlife this past week. 

Alewives are a nonnative fish species that play a role similar to smelts in large lake systems.  Biologists are concerned about the rate at which alewives have established themselves in the lake, and potential ecological consequences to the rest of the lake’s fish community.

Read more here

According to Peter Rolfe of the Australian Herald Sun, some in the Australian government are pushing to eradicate trout from some of the continent’s waters in hopes of restoring native species.  But such an idea doesn’t sit well at all with Aussie anglers.

Commission chief Wendy Craik conceded the removal of trout was a sensitive issue.

“I can understand that fishing people might be upset about this but we need to look at what is best for our rivers and native fish,” she said.

Trout were introduced to Australia beginning in the 1870’s, and the popularity of trout fishing has grown over time to the point where it provides an annual industry worth about $1.3 billion, much of that money brought in via fishing-related tourism.

Anglers and local residents are outraged, and argue that removing trout will be devastating to local economies.  In addition to removing trout, other fish species such as carp are expected to be targets for removal.  Many anglers do not oppose the removal of less desirable fish, but draw the line at trout.

In the Western United States native fish are plagued by nonnative trout introductions as well, but removing nonnative trout often opens the door for better opportunities to catch native trout species, which can be equally enjoyable to pursue.  Australians aren’t so lucky.  Removing trout from their waters would likely cause much more devastating impacts to recreational fishing because Australia lacks native trout. 

So will it be ’out with the trout’ in Australian waters?  Time and politics will tell.

Japanese officials are encouraging people to catch and kill bluegill caught in Japan’s waters in an effort to reduce competition between bluegill and native fish.

Bluegill were brought to Japan in the 1960’s as a gift from Chicago mayor Richard Daley to the emperor of Japan.  The emperor has since stated that he regrets what has happened as a result of bringing the nonnative fish species to Japan, and efforts are ongoing to rid the country of bluegills.

See the story here

While they can be very popular sportfish in some parts of the world, and have a small following here in the U.S., carp are generally considered a serious nuisance to most anglers and water users in America.  This is particularly true in the Midwest, where carp have taken over a large percentage of lakes and ponds, mucking up the bottom and destroying plant life, making it hard for other fish to survive.  You can read more about carp in one of my previous blog posts, entitled Carp…Those Pesky Critters!

Although carp have destroyed many midwestern lake ecosystems, University of Minnesota researcher Peter Sorensen believes that it doesn’t have to be that way.  With support from a number of different user groups and agencies, Sorensen has begun research on potential methods to eliminate carp in lakes. 

Efforts to remove carp from lakes can be successful, but require huge amounts of time and labor, and sometimes aren’t cost effective.  Sorensen is working on ways to change this, like developing pheromones to lure carp to a central capture location, or create scenarios where other fish eat juvenile carp.  Time will tell whether or not such methods can prove to be effective, but if they are, they will benefit people with carp problems all around the world.

Read more about the potentially groundbreaking research here 

Montana fisheries biologists are trying to determine the effects of nonnative lake trout in Swan Lake, located in the northwestern part of the state.  The lake is home to native bull trout, which usually suffer declines in the presence of lake trout.  In fact, the lake supports one of the only remaining sport fisheries for bull trout.  Lake trout were discovered in the lake in 1998, and they are expected to have a significant negative effect on bull trout, likely through both competition for food and space, and predation on bull trout by lake trout. 

Biologists will use trap nets and gill nets to capture lake trout.  After collecting data, they will place a mark on each fish and release it, which will allow them to estimate the population when they return and sample the lake again.  They also plan to place radio tags in a subsample of lake trout so that they can track their locations during the upcoming spawning season.  Identifying lake trout spawning areas can be very crucial in designing capture methods to control the lake trout population. 

Read more here

A number of lakes in the West have been affected by nonnative lake trout, including Yellowstone Lake in Wyoming, and Lake Pend O’reille in northern Idaho.  In Yellowstone, an intensive gill netting regiment on lake trout spawning grounds in the fall is allowing biologists to keep populations at a level where native Yellowstone cutthroat trout can persist.  In Lake Pend O’reille, recent research is showing that the combination of an incentive program (anglers are paid $15 for every lake trout they kill) and a commercial trap netting operation for lake trout have the potential to drastically reduce lake trout populations to the point where they have little effect on kokanee and bull trout.  Hopefully Montana biologists will  be able to use the scientific data provided in recent research projects on these lakes and others throughout the West to implement strategies to protect their native trout.

Up until now, I haven’t mentioned anything on this site about the discovery of invasive didymo algae (also known as ‘rock snot’) in the Upper Connecticut River, which could have widespread negative impacts for fishermen and recreationists alike. 

The topic has been covered extensively in the news media, and more information and discussion can be found at the New England Outdoor Voice Website. 

Recently, didymo has been discovered in Vermont’s Batten Kill River, which boasts a world class trout fishery.