Now We Wait for The Environmentalists…
By jimrob | April 7, 2008
Ad-Express and Daily Iowegian, Centerville, IA - Living fossil found at dam
How did the chestnut lamprey population come to be at the site? Flammang believes they traveled on host fish up the Chariton from the Missouri River.
“The historic occurrence of chestnut lampreys in this river segment is doubtful,” writes Flammang. “None of the previous fish surveys of the Chariton River for example, Jordan and Meek 1885, Harrison and Speaker 1954, and Harlan and Speaker 1956 —including a fish survey conducted on the Chariton River just prior to the 1969 impoundment of Lake Rathbun Mayhew 1965 —produced records for this species.”
The DNR biologist based at the Rathbun Fish Hatchery says there are two likely possibilities.
“The lampreys moved up the Chariton River from the Missouri River attached to highly mobile host species, such as common carp, during recent high-flow events,” Flammang conjectured. “For example, the prolonged high river flows in the Chariton River and most other Iowa rivers in summer 1993, no doubt, induced more upstream movement than normal of fish such as common carp, and parasitic lampreys may have thus moved upriver in the Chariton as far as the barrier presented by Rathbun Dam.”
The second possibility he puts forward is, “The lampreys moved up the Chariton River from the Missouri River attached to the highly mobile bighead carp as the distribution of this non-native species rapidly expanded northward into Iowa waters during the 1990s.
“The first report of the bighead carp in the Chariton River below Lake Rathbun occurred in 1995; the first report of a parasitic lamprey from this LOCATION occurred in 1996, thus suggesting at least the possibility that chestnut lamprey arrived with this recent non-native invader.”
Flammang concluded: “The mid-1990s appearance of chestnut lampreys on host fish in the Chariton River downstream from Rathbun Reservoir represents the first occurrence of this species from interior waters in Iowa in over 100 years. Special conditions in the mid-1990’s—whether the prolonged flooding of the Chariton River along with other Midwest rivers in 1993 or the arrival of a highly mobile non-native fish species bighead carp in the Chariton River in the mid-1990s—most likely led to the introduction of this species in the Iowa portion of the Chariton River.
“The existence of favorable habitat conditions in the Rathbun Dam tailwater, including low turbidities, stable flow, and abundant host fish, likely have contributed to the establishment of an apparently viable population of chestnut lamprey at this LOCATION.”
This should prove to be quite the news story. The lamprey in question is an endangered species, which could introduce a whole host of problems. Rathbun Lake is a major source of water for Southeastern Iowa. This “living fossil” was found at the lake’s spillway. The spillway, of course, regulates the level of the lake by varying it’s output into the Chariton River.
There are times where the level of water in the Chariton River has been lowered to a depth of six inches (I’m not kidding) to keep enough water in the lake to provide for the water treatment plant. If it’s determined there must be a minimum amount of water in the river to facilitate this creature’s survival, what’s going to trump; the water in the lake (also a major recreational area in addition to being a water supply), or the level of water in the river?
Given the precedent set by the Fish and Wildlife Service in the Pacific Northwest, I’m not holding out much hope for a common-sense outcome.
Topics: Iowegia |
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