From the Maine Department of Fish & Wildlife comes this interesting story regarding competition between the state’s native populations of Arctic char and rainbow smelt:
The story begins with arctic char, also known as blueback trout. Maine is the only state in the lower 48 that has native populations of artic char and, even in Maine, they can only be found in 14 remote waters in the western, eastern, and northern sections of the state. Char are very sensitive fish that require precise conditions in order to thrive and reproduce. Most waters where char reside also support brook trout and from one to several species of native baitfish.
Char spawn on rocky shoals in the fall and their eggs will hatch in the spring. Most char average 6” to 8” long, but fish in excess of 3 pounds are occasionally observed. While we are truly lucky to have char, their presence requires us to be very strict about keeping our waters clean, cool, and oxygenated, and we must limit any competition caused by introduced species, including some species of baitfish that are desired and prevalent in other waters.
Rainbow smelts are a prolific fish that average between 3” to 5” long and are prized by many fisherman both as baitfish and as a tasty meal. Smelts are found throughout the state, mostly in coldwater lakes and ponds. They spawn and hatch in early spring. Smelts are the primary forage fish for larger game fish such as landlocked salmon and togue, and for this reason they are often a preferred bait. Smelts are a great resource in many areas of the state, but when they find their way into char water, life as the char know it begins a catastrophic decline.
So now the question is raised, how can a 5” long baitfish devastate an entire population of game fish? Surprisingly, the answer is predation and competition. The emergence of char fry from the shallow shoals in April coincides with the spawning season for smelts. While cruising the shoreline seeking suitable tributaries or lake shoals for spawning, adult smelts intercept the emerging char fry and feed on them voraciously. We believe this occurred recently at Big Reed Pond and Wadleigh Pond in northern Maine.
In addition, young char forage primarily on plankton and aquatic invertebrates until they are large enough to eat other fish. Young smelts, dace, and brook trout all have the same food habits. Before you know it, you’ve got every small fish in the lake eating plankton, and only so much forage to go around! The ones that can consume enough, grow. The ones that don’t consume enough don’t grow, so their productivity and their ability to produce eggs decline. When this happens on a broader scale, there are fewer fish replacing the adults of that species when they grow old and perish. Very quickly that entire population begins to decline and, if it’s not noticed and rectified quickly, that species may disappear permanently from that water.
Recently, multiple char waters have been found to have some kind of introduced fish species. Sometimes that species is smelts (as noted above), and when smelts are feeding on and competing with char, they are no longer a beneficial baitfish. These innocuous, tasty little fish that smell like cucumbers and attract big fish, become relentless predators and competitors that, instead of attracting big fish, extirpate them. When that happens in a char water, there may be no going back.
If we are not careful, Maine could easily lose a treasure that only one other state (Alaska) has the honor of having. What is the only thing that stands between our healthy char ponds and this desolate tragedy? People like us who love and enjoy these resources.
In both of the char waters discussed above, smelts were introduced illegally. They did not arrive at Big Reed Pond or Wadleigh Pond on their own. It may seem that a few lost baitfish or one dumped bait bucket couldn’t possibly harm a whole lake, but that is exactly what can happen. Although many lakes contain complex food-webs consisting of a variety of fish species, there are those lakes that are much more fragile and very easily impacted.
So, please do not transport and release fish of any size in natural waters. In addition to it being against the law, it may cause a unique and balanced ecosystem to become forever lost.
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