River Research Proposed

We have long been aware of a steady decline in the numbers of larger trout in the Au Sable River system. While the river continues to recruit large numbers of trout into the one-year population, long term electroshocking data since the early seventies has shown that survival rates for two-year old and larger fish have become a persistent and worrisome problem. There are yearly fluctuations, but the twenty-year trend cannot be ignored.

It should be noted that this trend is true for all northern Michigan rivers and that the decrease in larger fish is not limited to the Au Sable.

The Anglers have advocated and supported trout and river research for a long time. An example is the support given to the telemetry study of the movement of large trout in the Mainstream.

Recently, over the past several months, representatives of The Anglers have been involved in a number of meetings of the Au Sable River Study Committee, a group being formed to carry out a very broad based group of studies aimed at developing guidelines for the management of the upper Au Sable River basin. This committee consists of individuals representing diverse organizations including The Anglers, the DNR, T.U., Chambers of Commerce, AMAC, the Huron Pines RC&D, canoe liveries, other commercial interests, property owners associations, and scientists from our state universities. The hope of the majority of the Committee is that such a group can develop and fund a series of studies designed to resolve the problems that have caused the decline of this river and which would thereby contribute guidelines to a river management district. The political realities of this latter function are currently unknown and at the proposal stage.

The proposal for river study has been generally agreed upon and contains a number of separate studies. For example, DNR personnel believe that the loss of woody debris is the most likely contributing cause for the decline in larger fish populations. They propose a study in which the numbers of trout are measured before and after the introduction of LWD in the form of whole trees in two-mile-long river segments at Dam Four and Eamons on the North Branch. They also want to monitor the effects of additional organic matter in the form of leaf litter in segments at WaWaSum and Stephan's Bridge on the Mainstream.

Other studies proposed include those designed to better understand stream morphology and gauge the impact on trout food sources, and a long term retrospective analysis of the river's water chemistry history to better assess the present day water chemistry profiles. Water temperature will also be monitored on a continuing basis.

Decline in food supply, mechanical stress, loss of large woody debris for cover, and possibly longer term but subtle changes in water chemistry have received most of the emphasis from the scientists involved. However, there is an agreement that the impact of the toxins moving out of the National Guard ranges will be included in their analysis.

There also have been recent fish autopsies and at this writing the presence of whirling disease or other infectious diseases is not known. We will report that information as soon as it becomes available.

Fish harvest and regulations are not seen as current important contributors to the fish population declines. DNR personnel are minimizing the role of poaching, fish genetics, fishing pressure, and so on, and feel that the decline in the number of larger fish is independent of both long term trends in fishing pressure and specific regulations. We feel this is unfortunate, but this area continues to be debated and possibly research data may shed a different light on the effects of regulations.

The position of The Anglers is that all of these studies should be done simultaneously. Whether the Water Management District can become functional to implement recommended actions remains to be seen. It is our position to aggressively support watershed research. The first elements of the research, if funding is found, will begin this spring with additional analysis completed in the fall of 1998.

RWOL

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