Sea Lamprey

The bright red roofs of the Hammond Bay Biological Station glow against a blue northern Michigan sky. Set on the shores of Lake Huron, this site is biologically interesting in more ways than one. We stopped by on one of my recent NettieBay Lodge excursions looking for interesting birds and plants. A ribbon fen runs along the entrance drive, which is full of Pitcher-plants and Bogbean, among other interesting plants. The shoreline of the lake sports yet other noteworthy plants, and the birds are always diverse. Both Common and Red-breasted Mergansers can be found on the lake, there is a thriving Cliff Swallow colony under the eaves of one of the buildings, and Merlins nest nearby.

On this foray, a gentleman who works at the station stopped by to see what we were ogling (the fen and its plants). I struck up a conversation, and that led to an informal tour of the biological station. That proved so interesting that we scheduled a formal tour for our second group, and I'm glad that we did. I think tours of the Hammond Bay Biological Station will become a standard feature of our NettieBay trips.

The Hammond Bay Biological Station is all about Sea Lamprey, Petromyzon marinus. These large eel-like fish are native to the Atlantic Ocean, but invaded the Great Lakes in the early 1900's after the Welland Canal - which bypasses Niagara Falls - was enlarged. Their numbers quickly exploded, and by 1940 had occupied all five of the Great Lakes.

There are several ways to control lampreys, and this small dam, with an attendant electrical barrier, is one of them. Sea Lamprey run up streams and rivers to spawn, and disrupting this part of their life cycle is one way to attempt to reduce their numbers. This barrier is along the Ocqueoc (Ok-quee-ok) River, not far from the biological station. A few years ago, researchers trapped about 26,000 lampreys below this dam, which gives an idea of the severity of the invasion. Sea Lamprey breed in scores of other Great Lakes tributaries.

Other lamprey control techniques that are in place, and which the biological station is constantly striving to improve, include: lampricides, which are chemicals that kill the larval stage of the lamprey; trapping; the aforementioned barriers; and pheromones which repel the lamprey.

Here's a Sea Lamprey in the flesh, one of many live specimens that the Hammond Bay Biological Station has on hand. It's a decent sized animal, and nearing the upper limits of what lampreys in the Great Lakes can grow to. In their native marine habitat, Sea Lamprey can grow considerably larger. In the ocean, however, where all of the prey have co-evolved with lamprey, the parasitic fish don't wreak the havoc that they do in the Great Lakes.

Your narrator acts the part of a fish, and allows a lamprey to clamp on. Adult Sea Lamprey feed by attaching to a host fish with specialized mouth parts (as we shall soon see). Once the lamprey has firmly bonded with its victim, it begins extracting nutrients.

A closeup of the lamprey connected to my hand. Fortunately, they are programmed to feed only on cold-blooded organisms - fish, in this case - and warm-blooded animals such as myself do not trigger the rather brutal process of nutrient extraction. Even though we humans may not be part of the lamprey's menu, they certainly will clamp on with vigor!

Looking like something straight out of a sci-fi horror film, this is the "mouth" of the Sea Lamprey. The fleshy ring surrounding the mouth grips like a suction cup, albeit a VERY strong suction cup. They claim that a lamprey can generate roughly four times the force of a vacuum cleaner, and after allowing one to attach to me, I'd buy that. All of those teeth apparently help hold it in place, and once the connection is solid, the fun begins. A raspy-roughened tongue emerges from the center pit, and files away until a hole is sawed through the fish's skin. Anticoagulants are released, the better to keep the juices flowing, and the lamprey begins sucking its sustenance from the victim.

Lampreys basically lurk discreetly in the water column, and when a suitable prey item is located, the lamprey sidles near and in a quick burst of speed, lunges and instantly locks onto its host. In the sea, many of the lamprey's prey species are large enough that they can deal with these parasites, and the lampreys do not necessarily kill the host. The Great Lakes fish are not as large or as resilient, and Sea Lamprey have caused enormous declines in fisheries, especially of the native Lake Trout, Salvelinus namaycush. One adult lamprey can kill up to 40 lbs. of fish over the course of its life. Other host include large fishes such as Walleye, Northern Pike, Lake Sturgeon, among others.

Seldom able to resist an interesting photo op, your blogger has attached a lamprey to his forehead. Now that I know firsthand what this feels like, I cannot imagine the adverse impact that having such a beast attached to a 30 or 40 pound Lake Trout must cause. Even though the lamprey was only bonded to my head for less than a minute, it left a slight purplish bruise for the better part of a day.

The efforts of the Hammond Bay Biological Station's lamprey research has reaped a lot of success. Lamprey numbers have been greatly reduced in all of the Great Lakes, and especially in Lake Superior. In many regions, lamprey numbers have been reduced by about 90% of their historic, pre-control highs. Great Lakes fisheries are incredibly important and well worth protecting. About five million anglers troll the waters of the Great Lakes, and fishery-based work creates about 75,000 jobs. The total fishery produces about $7 billion annually, so the funds spent to manage the invasive lampreys is well worth it.

We'll soon have the dates set for next year's NettieBay Lodge trips, and if you go, we can probably arrange for you to have a Sea Lamprey stuck to your flesh, if that's really what you want.