Ed and I would like to get you an update, and share some observations.

We are halfway through the fishing season, and things are going well. This is a transition time- fewer tournaments, and possibly fewer anglers during the heat of August, but it is a very important time for collections, so keep collecting if you can. We want to see how and when predators respond as the young of the year fish hatched become large enough to be eaten. We can then compare those results with our trawl data to determine if predators prefer certain prey species over others.

We have crew of three going through stomachs madly, and are eliminating the backlog. I think we have processed over 250 stomachs so far, and the pace has picked up. Normally, when doing a study like this you wait until all data are in before releasing any results. The reason is that your first impression can be dead wrong, and you really don't know until you have seen all fish what trends are present. But, people are anxious for some results and we decided to share some very preliminary observations with the caveat that we are less than 1/3 of the way through the stomachs we have collected to date, more stomachs are coming in every week, and diets will change through the season.

Round gobies are the most common fish species eaten by far, and they will likely dominate lake trout diets if their prevalence continues.

A few alewives have been observed, but they are sparse in diets and were only seen in Chinook salmon taken near Rogers City recently.

We sampled a tournament that occurred several days after a lake trout stocking. The most common prey of large lake trout was, you guessed it, recently stocked lake trout. Not every adult lake trout had cannibalized the juveniles, but there was little else in the diets.

Saginaw Bay walleyes have a diverse diet that includes yellow perch, shiners, and round gobies, but they are also eating invertebrates. We found several that eaten midges and mayfly nymphs. These are spring samples, and we have not gotten to the summer collections yet. The mayfly observation was interesting because mayflies have not returned to the Bay the way they have in Lake Erie, and many people wonder why. In fact, it is difficult to find any mayfly nymphs in the bay at all. Yet walleyes found some.

We also found whole worms in walleye stomachs. These were undoubtedly stolen from anglers, but the fish did not quit when they were ahead and were subsequently caught later that day.

We found that some lake trout collected this spring near Rogers City had eaten large numbers of terrestrial insects. Some stomachs contained over 1,000 insects. We actually looked at the individuals, and found beetles, flies, wasps, and leafhoppers. You would expect this type of diet in a steelhead, but not a lake trout. This has gotten us thinking about terrestrial insects as an energy source that may have been underestimated ... it also makes us believe that lake trout were foraging at the surface similar to the way steelhead behave in scum lines. Go figure.

So we learned all this via the May and June collections, think of what we may learn if we can keep this going for the entire season! Keep up the good work!

Ed and jeff