Recently we attended a campground talk on invasive species in the Great Lakes. An invasive species is defined as a non-native species. Most are environmentally harmful, although this is not always the case.
Around a dozen invasive species inhabit the Great Lakes, but the talk focused on these five: sea lamprey, zebra mussel, Eurasian water-milfoil, Eurasian ruffe, round goby.
The sea lamprey (Petromyzon marinus) is an eel-like jawless fish 12 to 20 inches long with a suction-cup mouth filled with sharp teeth. Sea lampreys are parasites. They attach to other fish, chewing a hole and sucking their blood. This “kiss of death” scars and often kills the host fish.
Fish have been found with as many as four lamprey suck-marks. During its lifetime a sea lamprey will kill over 40 pounds of fish.
Sea lampreys feed on salmon, lake trout, steelhead, whitefish, walleye, and lake sturgeon. They contributed to the collapse of the lake trout fishing industry on the Great Lakes.
Sea lampreys are native to the Atlantic Ocean, but they are now in all five Great Lakes and many tributaries. The greatest concentration is in northern Lake Huron. They entered the Great Lakes in the sea water ballast of freighters as did the other four invasives.
The zebra mussel (Dreissena polymorpha) is a fingernail-sized barnacle with alternating dark and light stripes on its shell. Zebra mussels grow in clusters that attach to hard surfaces. They clog water intake pipes and pumps at power plants and water treatment plants, costing millions of dollars annually.
The clusters also attach to boat motors, hulls, and dock pilings. They attach to native clams and mussels, and the accumulated weight of the cluster prevents the mussel from opening, thereby smothering it.
Zebra mussels wash up on beaches where their sharp shells cut people’s feet. Zebra mussels consume vast amounts of plankton which disrupts native food chains.
Zebras were first discovered in 1988 in Lake St. Clair. They have since spread to all the Great Lakes and many inland lakes and streams.
The Eurasian ruffe (Gymnocephalus cernuus) is a small brownish fish that will fit in a man’s hand. Sharp spines on its top and bottom fins discourage larger fish from eating them. The ruffe has a huge appetite and devours food normally eaten by native fish. Ruffe populations mushroom rapidly as they reproduce in their first year with females producing up to 200,000 eggs per season.
The round goby (Neogobius melanostomus) is a small bottom-dwelling fish with a big head and frog-like bulging eyes. Despite growing no longer than seven inches, it’s an aggressive fish which crowds out other native species. It takes over favored habitats, spawning grounds, and feeding areas from native species. They eat the eggs and young of other fish.
The round goby was first discovered around 1990 in the St. Clair River which runs from Lake Huron to Lake St. Clair. We were camping right on the St. Clair River when we learned about the round goby invading the river near where we sat.
Eurasian water-milfoil (Myriophyllum spicatum) is a water weed. With feathery leaves and long, stringy stems, EWM forms thick vegetation mats in lakes and rivers that block sunlight needed by native aquatic plants that provide food and shelter for fish. EWM chokes boat propellers thereby hindering boating, as well as swimming and fishing. EWM grows like a weed; from the tiniest plant fragment it can take over an entire inland lake. Plant control costs run to many millions of dollars annually.
When You Cross Jack Russell with Harley Davidson…
…you will get the invasive species pictured here that camped near us in the campground.
Pork Chop is the name of the Jack Russell terrier on the motorcycle. By definition he would be considered an invasive breed. The breed was developed in England by Parson Jack Russell to hunt small game and later imported to the U.S.
Pork Chop rides on the motorcycle as shown barking loudly for the whole trip. We could always tell when the owner left or returned to the campground — more by the barking than by the roar of the Harley. This particular 7-year-old dog from Louisville, KY got its name from stealing a pork chop off his owner’s plate.
Our Jack Russell terrier Kepler and Pork Chop became friends at the campground. Kepler watched his comings and goings on the motorcycle with keen interest.
The term “invasive species” is somewhat artificial. At creation, every species was invasive, yet none was harmful at that point. Every land species after Noah’s Flood was initially invasive.
Yahweh designed flora and fauna to reproduce after their own kind (Genesis 1:11-13,21-22,24-25). As they proliferate, life kinds will naturally spread out and invade new areas.
A more valuable designation than “invasive” is “environmentally harmful.” Many dog breeds have been developed overseas and imported to the U.S. They are invasive but not harmful.
Yahweh gave Adam oversight responsibility. So it’s appropriate for man to determine habitation bounds for species. However, I would make these judgments based not on whether or not a species is invasive (non-native), but rather on whether it’s harmful.
God created man in His own image, in the image of God He created him; male and female He created them. God blessed them; and God said to them, “Be fruitful and multiply, and fill the earth, and subdue it; and rule over the fish of the sea and over the birds of the sky and over every living thing that moves on the earth.” (Genesis 1:27-28)
Questions to Ponder
- Have you experienced harmful effects from an invasive species, perhaps in your garden or landscaping?
- What are examples of beneficial invasive (non-native) species?
Share your thoughts on these questions in the comments below. It could encourage or help another reader.
Soli Deo Gloria.
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©William T. Pelletier, Ph.D.
“contending earnestly for the faith”
“destroying speculations against the knowledge of God”
(Jude 1:3; 2 Cor 10:4)
Wednesday June 17, 2015 A.D.
It is the Lord of hosts who made the earth by His power, Who established the world by His wisdom, and by His understanding He stretched out the heavens. (Jeremiah 51:15)