Lakes Restoration Project

Wildlife and the Lakes Restoration Project

Bruce Carlson

In recent weeks, several Loch Alpine residents have contacted members of the Lakes Committee with expressions of concern about the effects of the lakes restoration projects on the wildlife associated with the lakes. This article is being written a bit over a week after the partial filling of the upper lake, so it can be used both as an update and as a general perspective on the issue.

If there is any one theme to cover this issue, it is that Nature abhors a vacuum. We are already seeing this in spades concerning the refilling of the upper lake. Just a couple of days after the water in the upper lake reached the base of the land bridge to the island, I walked along the shore and saw several schools of young minnows swimming right along the edge. Even though the lake bottom was scraped quite clean, many land plants had grown up on the soil and are now under water. This is very good, because in the absence of the normal water plants they provide cover for the small fish and other animals that are already repopulating the water. By the way, with the draining of the upper lake, the stream was effectively lengthened, thus providing increased habitat for stream minnows, which undoubtedly spawned in that stretch of stream earlier this spring. The minnow fry are now swimming in the lake and will form a significant part of the near bottom rung of the food chain that is necessary for the larger animals to survive.

This evening, I already heard bullfrogs and green frogs in the upper lake. These had undoubtedly migrated from the lower lake, following cues that scientists still don’t well understand. Several upper lake residents have seen turtles crossing the road from the lower into the upper lake. I’m sure that the muskrats will be back soon, as well. Aquatic insects hatching from the lower lake will soon lay eggs in the upper lake, and with their enormous reproductive potential, there should be healthy populations of the insects needed for food by the fish and larger invertebrates. We will probably see a shift in the kinds of insects hatching from the lakes. With the removal of the silt, we should see more mayflies and other insects that require clean lake bottoms for survival of their larvae. These insects will bring the tree swallows back to the upper lake for their morning and evening feasts on hatching insects. Right now (July 8) the lower lake is in the middle of a large hatch of damsel flies, the smaller cousins of dragon flies that keep their wings at rest straight up over their back, rather than airplane-like as do dragon flies. Dragon flies eat huge quantities of mosquitoes, so their presence should be very welcome. Another less prominent, but extremely important invertebrate is the crayfish, which constitutes one of the major foods of large bass. While normally living in the lake bottom, they are quite capable of living in wet mud near lakes. I wouldn’t be surprised if many crayfish survived the winter in the mud of the upper lake and will now go back into the water now that the lake is filled. Others will come in from the stream.

Some fish will re-enter the upper lake from the stream where they took refuge when the lake was drained. Many of us who watched the final draining of the lower lake saw fish swimming up the stream when the water had run out. A number of Loch Alpine residents have been catching fish in the lower lake and releasing them into the upper lake in order to re-establish good fish populations as rapidly as possible. We are trying to keep track of what is put into the upper lake so that we can try to get things started with balanced populations of the major fish species. If you have put any fish into the upper lake, please contact me by phone (426-2232) or by e-mail (brcarl@umich.edu) and tell me approximately how many and what kinds you have put in. Before it was drained, the upper lake had a large resident carp population. With the drainage, all of these went into the lower lake, where they are now muddying the water in the spillway end of the lake. Unless significant numbers of carp escaped up the stream into the golf course area, the upper lake should no longer have a carp population unless new ones are introduced.

Although the schedule is not yet established, the lower lake will probably be drained by the third or fourth week in July. What will happen to the wildlife in that lake? It is likely that most of the fish will die, since the DNR doesn’t want any of them released into the Huron River because of the carp problem. This is one argument in favor of draining the lower lake, since that will effectively deal with the carp population. Another option that was briefly discussed was to treat the lake with rotenone, a fish poison to remove the carp, but the DNR nixed that plan because of possible spillage into the Huron River. It is highly likely that all of the bullfrogs will move to the upper lake for the rest of the summer. By the way, soon you won’t hear their honking because their breeding season is almost over and they are quiet during the late summer. The turtles and muskrats will either move to the upper lake or the river. The ducks, egrets, kingfishers and herons will temporarily move to other feeding grounds. Cleo, “mama swan,” will certainly fly to the upper lake, where I’m sure she will continue to be well cared for by Nona Credille. It’s anybody’s guess what the geese will decide to do for a while.

Just a word about “weeds.” A certain amount of weeds are important for the health of any lake. What we want is for the right kinds to grow. The early summer weeds that have been choking our lakes are the curly-leafed pondweed, a non-native species. These grow exuberantly during the early summer and then rather rapidly die back. This was very evident in the lower lake over the Fourth of July long weekend. On July 4, much of the lake was covered with dense mats of the weed, but then it began to die back within just a few days. The next major type of weed is the coontail, which is a desirable weed that provides good cover for fish and aquatic invertebrates. Coontail is just beginning to emerge, and it will be important to have some of that growing in the upper lake. Water lilies have been proliferating greatly in the lakes in recent years because of the great amount of muck, in which they thrive. Bart Wise is going to try to re-establish some stands of lilies in the upper lake from tubers that he saved last fall or from transplants from the lower lake. A thick spongelike weed, actually an alga called Chara, is an important weed that carpets the lakes. This will probably re-establish itself over time. The amounts of the slimy strands of dark green algae that are especially prominent in the spring, but are present even now, will be reduced because of the amount of phosphorus that is being removed with the silt. The more that we can collectively keep additional phosphorus from entering the lakes from fertilizing lawns, soaps and detergents, etc. the healthier our lakes will remain.

One additional comment on frogs, especially bullfrogs, is in order. Many residents on the lakes love to hear their calls at night. Their populations go up and down in cycles, and presently their numbers are the greatest that I have seen in over 30 years on the lakes. One reason for this probably relates to the amount of weeds in the lakes. These provide excellent cover for both the frogs and any tadpoles that might be present in the lakes. Bullfrog tadpoles are unusual in that they remain as tadpoles for two years instead of the one summer that is usual for other species of frogs. Bass love frogs and tadpoles, and it is quite possible that with less cover available, few tadpoles will be able to survive in the lakes. However, a solution to this problem might be present in the retention pond in the upper lake. If we can keep bass out of this pond, it could prove to be an ideal breeding spot for frogs and toads.

Once the lower lake gets refilled, especially if it is done before the weather gets cold, I would predict a very rapid return for many of the animals that used to live in it. The main problem will be the fish, because there won’t be enough fish in the upper lake to restock the lower one. It will be necessary to purchase a basic stock from a fish farm. For both lakes, fish will be relatively scarce for a couple of years, but once the first batches of young sunfish and bass come out, there will likely be a period of very rapid growth. It is the common experience in new reservoirs that 4-5 years after they have formed, fishing is fantastic. Then things come to an equilibrium and fishing success tapers off. The biggest trick is to prevent the population of one species from exploding and becoming over-abundant and stunted because of lack of sufficient food. Sunfish populations are especially likely to do this, but I have seen a number of lakes with similarly stunted populations of bass. This was beginning to happen in the lower lake, although there are still some very large bass in the lake, as well. These get big by eating smaller bass. A few years ago I saw what looked like a huge dead fish on the shore of the lower lake. It turned out to be a 21” bass that had tried to eat a 20” bass, and the smaller bass had gotten stuck in the throat of the larger one and both died. Just this year I saw a roughly 4-poound bass jumping in some distress. I could see the tail of what looked like a 12-14” bass protruding from its throat.

In sum, there will certainly be some temporary disruption in both lakes as a result of the restoration project, but I think that you will be amazed and pleased at how quickly the biological equilibrium returns. If you have any specific questions on any aspect of the lakes renovation project, please contact the Lakes Committee co-chairs. Jim Christman is the main interface with the excavator and with JJR, which is overseeing the project. For engineering issues, please contact Barney Thomas, and for biological or ecological issues, give me a call.

Bruce Carlson