If you've spent much time walking along the beaches here in Northern Michigan chances are you have come across a thing or two that made you wonder how did that end up here? One of our viewers, who spends a lot of time at the shore, had a much more puzzling question. He wondered not how did that get here, but rather, what is that? The answer I found for him and at look at what most likely killed it is the subject of this Fact Finder.

If you are trying to catch up with Bob Spencer, you probably better put on your walking shoes. For a 73 year old, this Benzie County man is on the move. As Bob explains it "Oh I walk all the time. I walked the shore all the way from Frankfort to Empire, pieces at a time, but I am there at least once a week sometimes twice a week. I love walking. I walk up the shore there I walk back in the woods and everything else."

He sometime takes his camera, and often returns home with more than he left with, "well I like to be out by the water, looking for stones and stuff, I just love it you know."

Bob does most of his walking along the shore of Lake Michigan in the Sleeping Bear Dunes National Lakeshore. Long walks up and down, looking for anything that catches his eye. But no discovery, in years and countless miles of beach walking stumped him like his most recent find.

According to Bob "I came across a funny looking, I called it an animal. I didn't even know it was a fish. It was 3 to 4 feet it was quite large. I looked more like a reptile its head was short it just didn't look like a fish. Nothing I have seen comes close to that head."

In decades of walking, Bob thought he had seen it all but this find stumped him so "The next day I went I am going to go take a picture of it. I took my camera back and I couldn't find it. Somebody had covered it up, so I looked around for a hump in the sand and I finally dug him up and I took the pictures of him, and sent one to you" Bob wanted to know exactly what this was so I sent the Bob's pictures straight to the experts at the National Park Service.

According to Chris Otto, a wildlife specialist "We are fairly certain it is a lake sturgeon that washed up."

The four foot long skeleton that Bob found would be a pretty average size sturgeon out in Lake Michigan. But on a larger scale, there is nothing average about these fish. Otto explains "The lake sturgeon are actually a really large fish. They grow up to almost 6 feet in length and weigh anywhere from 50 to 100 pounds. Their life expectancy is rather unique, a typical male is around 55 years and the females can range anywhere from 80 to 150. Unfortunately in any given year only 10 to 20% of the lake sturgeon go to spawn, which means their reproduction rates are very low."

And because they are so slow to reproduce, Otto says "Lake Sturgeon are on the state threatened list and I would describe them as a prehistoric fish. They say that because their existence has been traced back to the time of the dinosaurs so they are old they are actually called living fossils. And they are somewhat of a rare fish."

Rare to find out in the big water, but not as rare as you might think to find washed ashore at Sleeping Bear Dunes.

Otto says "In 2007, we actually had 3 so hopefully this is the first and last we will find this year. Anytime we see a threatened species wash up its significant. As far as it being extreme I don't know where you would draw that line. I would say if you see a couple per season it's definitely something to take note of and watch more closely."

So Bob, your fish was a sturgeon. But in light of their threatened status and current population, another question deserves an answer. Why did this fish, and on average 3 to 7 of them according to Steve Yancho with the NPS wash ashore along the dunes each year? Otto says botulism could be to blame. As Otto explains it "botulism is actually a toxin that fish ingest a neurotoxin that actually causes paralysis and ultimately for most species it results in death."

In the past 3 years, there have been numerous reports of dead birds washing ashore here. After testing, Type A botulism was found to be the cause of their death. While botulism has been in the Great Lakes for decades, it's been more common in recent years thanks to the arrival of other invited guests like zebra mussels and gobies. Otto says "the bacteria is natural and native to the great lakes ecosystem the conditions that are exasperated though we suspect to be a results of invasive species."

It only stands to reason that the same infected fish that the birds were eating were also being consumed by larger fish, like the sturgeon. Like it does in birds, botulism can take a deadly toll in fish as well. That's one of the reasons why the park service appreciates beach walkers like Bob keeping them posted on anything they find washed ashore.