Wednesday, March 11, 2009

Increased fish diversity-- good news

Will Wawrzyn of the DNR spoke at length yesterday at the PEE Committee meeting. I was particularly interested in what he had to say about fish diversity. He had a powerpoint slide showing that there was a jump in total number of species and total number of native species in the North Avenue Dam site in 1997 (the year of partial removal, though it had been open since late 1990.) I tried to find this specific slide online, but I found better: this 2005 DNR report that discusses the subject at length. In particular, I wondered if the increase in fish diversity and number was as much or more due to the abatement, removal, and washing out to the lake (since the dam was open for sediments to wash though) of PCB's, heavy metals, and whatever other contaminants had settled there.

Changing Habitat and Biodiversity of the
Lower Milwaukee River and Estuary

"The Kletzsch Park station is an upstream site, [upstream from the Estabrook Dam also] which was not influenced by the NorthAvenue Dam impoundment. The upstream end of the station is fast flowing riffle, immediately downstream of the Kletzsch Park Dam (see Figure 5). The downstream section has some deep holes, and glides with overhanging tree branches, large boulders, and undercut banks providing fish cover. We recorded a total of 29 native species in five years of sampling, ranging from 11 species in 1996 to 23 species in 2001(Table 7). We could not sample this section in 1997 due to logistical reasons. Common carp was the only exotic species captured. The few walleye that were captured belonged to the recent stocking effort, demonstrating that the stocked walleye swim past the Estabrook Falls and Dam. Almost all the species captured at this station were also found in the Capitol Drive station except an occasional brassy minnow and fantail darter. At least seven species occurred consistently in all samples – spotfin shiner, common shiner, sand shiner, bluntnose minnow, rock bass, smallmouth bass, and logperch – although the numbers differed from year to year."

Keep in mind that the Estabrook Dam is located between the Capitol Drive sampling site and the Kletzch Park site.

"Other dams on theMilwaukee River including Estabrook, Kletzsch and Thiensville should be studied to see if removal or fish passage can be accomplished with minimal impact to the environment and conflicts with different user groups in those areas."
Photo taken by me in October, 2007. I photographed what I thought was a random fisherman, and when I asked him a question about the area, I realized he is a man I work with. What a small world we live in.


Higround said...

Excellent data River Otter! After hearing Mr. W speak on this I was left wondering how the data above the Estabrook Dam would compare to his data from downstream. You have found and provided those exact answers. How encouraging to see this level of diversity already, which will only improve along with the general health/quality of the fish once the PCB's are remediated. Fine Post !!!

Tall Blue said...

I went to the same meeting and felt really ripped off and angry when Wawrzin danced around my question about how many species of fish were in the Estabrook Impoundment. He's a public servant and he didn't answer the question;instead he said there weren't enough fish to count. That wasn't true. We wanted a number not bullsh_t. Every fisherman knows finding fish is not a sure thing even at places that are loaded with fish. We also know the impoundment is unusual for SE Wisconsin in that some species of trout that normally don't migrate up river were there to feast on salmon eggs.

The River Otter said...

Tall Blue, as far as method used to find fish, they used a method not recommended for the average individual: shocking the water. I would assume that all fish in the area would respond to this. Actually, reading about this methodology reminded me of the time I saw a dog get tased. It was horrible.

Tall Blue said...

My point is that Mr. Wawrzin did not answer the question asked of him. The answer would have been the number of species found in the impoundment. In addition the shocking method is a lot like other kinds of fishing and if you don't shock the right time, or in the right place, you won't get the fish. Keep in mind the DNR does not include the entire sheet of water in their definition of the impoundment. The fish are quite prolific in the areas both above and below the muddy sludge by the islands. After the PCB clean-up scheduled for 2010, that will probably change, but the tests and studies were all rigged to have results which could be used to support their desired outcome.

Erik Helm said...

I can add my experiences of over 40 years living by the river.
Before the North Ave. dam was removed, rough fish dominated the river due to lower dissolved oxygen, warmer water, excessive siltation, and poor spawning gravel. Fish species were dominated by bullhead, carp, redhorse, chubs, and catfish.

After dam removal river conditions changed. Silt was moved by the river exposing gravel, riffles produced ideal conditions for aquatic insects, and oxygen levels increased. The rough fish were naturally replaced by smallmouth bass and rock bass. Both species, especially smallmouth need clean flowing water in order to survive. The rough fish were still present, but in much smaller numbers. This is the natural condition of the river where it has natural flow. All the way from West Bend on down.

The River Otter said...

Keep in mind, Erik, that the DNR report showed great fish numbers and diversity in the Kletzsh Park area- that falls is really a man-made dam, not a natural falls. The falls is above the Lincoln Creek confluence that brought in all the industrial toxins.