An Upstream Battle; Natural and Manmade Barriers Prevent Northerns and Other Fish From Reaching Some Inland Waterways

By DON BEHM

Ozaukee County boasts 26 rivers and creeks tributary to the Milwaukee River or Lake Michigan.

Road crossings offer motorists numerous glimpses of both named streams, such as Cedar, Ulao, Trinity, Mole and Sucker creeks, and unnamed brooks.

At first glance, the county’s inland water resources might appear to be a paradise for fish, said Andy Holschbach, director of the county’s planning, resources and land management department. “But that’s not the case,” he said.

An abundance of waterways alone does not ensure access to the creeks needed to sustain self-reproducing populations of northern pike and others, a new study says.

“Fish do not swim freely in all of our streams,” Holschbach said.

A check of just 11 streams found 100 barriers to passage, according to a report by Northern Environmental Technologies Inc. The company was hired by the county to complete a limited survey of inland waterways.

Some of the barriers prevent adult fish from swimming upstream in the creeks to spawn in wetlands or thick vegetation along stream banks, said Dale Buser, the company’s principal hydrologist in Mequon. Others block offspring from floating downstream to grow to maturity in deeper, wider water.

While piles of logs or tree branches form natural barriers at a few locations, most of the obstacles are manmade or the indirect consequence of human activities on the landscape, Buser said.

Improperly designed or installed culverts, low-profile dams or stones dumped on a streambed to provide a crossing are among the more common hand-made obstacles identified in the Ozaukee County study.

In-stream mounds of soil eroded from fields and construction sites show the impact of human activities elsewhere.

It doesn’t take much to block the progress of northern pike, said Will Wawrzyn, a fisheries biologist with the state Department of Natural Resources. These native fish are accustomed to low-gradient streams and are not built, like salmon or trout, to leap above rapids, he said.

The survey assessed streams from the point of view of northern pike, also known as northern and pickerel. This species historically had depended on small streams to gain access to shallow wetlands for spawning in early spring. Loss of spawning habitat and barriers to passage have eliminated northern pike from many inland waterways in southeastern Wisconsin, however.

Northern will not even attempt to jump into the end of a road culvert if it was placed just several inches above the stream bed, Wawrzyn said.

Several such perched culverts, as they are known, were identified in the study.

One directs Mole Creek beneath county Highway O, also known as Green Bay Road, immediately upstream of the creek’s confluence with the Milwaukee River. That is the end of the line for any native fish. They are blocked from reaching upstream ponds and wetlands that would be suitable for spawning.

Another of the perched culverts provides a farm vehicle crossing of Mole Creek south of state Highway 33.

Holschbach will not ask the county or private landowners to immediately replace the culverts.

The work can be done when road or culvert repairs are needed, he said. At that time, the study will provide a guide to installing “fish friendly” culverts that allow passage.

For the past decade, several property owners along Ulao Creek have told Holschbach that northern pike no longer spawned in upstream wetlands where they had routinely appeared in past years.

This stream forms in wetlands south of Port Washington and flows south to its confluence with the Milwaukee River in Mequon. Historical accounts describe northern pike spawning as far upstream as the wetlands at its headwaters.

“So the county decided to look at the big picture,” Holschbach said. “We wanted to know what was limiting the potential of our water resources,” and curtailing recreational opportunities, throughout the county, he said. A $15,000 state grant helped pay half the cost of the survey.

One goal of the study “is a self-sustaining population of northerns in the county,” Buser said. “This is possible if we provide fish access to the habitat.”

Then county residents could fish close to home, along the Milwaukee River, rather than driving north in pursuit of northern pike, Holschbach said.

Field inspections found 10 fish barriers along Ulao Creek. One of the impediments is a large mound of sediment in the creek immediately downstream of culverts beneath I-43.

Northern Environmental researchers also found stones in the channel beneath a railroad bridge, and stones on the creek bed of a horse farm, providing a crossing for animals.

Such obstacles could be eliminated by removing the stone, Holschbach said.

“We’ve already talked to members of the Ulao Creek Partnership about helping us remove some of those,” he said. The partnership is a local organization of creek property owners and other county residents.

Buser recalled northern spawning in a low-lying field of a relative’s farm adjacent to a stream designated in the report as unnamed creek 2. It is known locally as the Highway W creek. The stream begins northeast of the intersection of Meadow Lark Road and state Highway 57 and flows south to its confluence with the Milwaukee River north of Saukville.

Finding barriers

There are historical reports of northern pike migrating upstream north of Hawthorne Drive.

The survey confirmed six barriers to migration. Among them is an accumulation of sediment pushed out of the culverts beneath Highway 57 and mounds of sediment upstream of Willow Road.

Ryan McCone, a natural resources scientist at Northern Environmental, has heard stories of northern pike spawning along the stream that drains Mud Lake.

“There used to be a pike run all the way up to Mud Lake,” McCone said. The outlet stream is a tributary of Cedar Creek.

The study revealed nine impediments to fish movement along the narrow waterway between Cedar Creek and Mud Lake.

One is an old concrete and stone farm bridge on the brink of collapse slightly downstream of the lake. Another is an old culvert crossing the stream about 1,000 feet north of its confluence with Cedar Creek. Sediment has accumulated in culverts beneath county Highway NN.

The DNR would encourage other counties in the region to complete similar surveys for fish barriers on small streams, Wawrzyn said.

“Many of the smaller streams are intermittent, without water flow later in summer,” he said. Yet, those seasonal streams would provide spawning habitat in late March and April if the fish could reach them.

Copyright 2007, Journal Sentinel Inc. All rights reserved. (Note: This notice does not apply to those news items already copyrighted and received through wire services or other media.)

(c) 2007 Milwaukee Journal Sentinel. Provided by ProQuest Information and Learning. All rights Reserved.