Who would have believed that you could catch a largemouth bass, or much less a spotted bass, on a 9-inch swimbait? And how about that crazy looking Alabama rig? No way would that work.
But it’s not only in bass fishing that nature constantly reminds of how little we know.
Perhaps the coelacanth provides the best example. The primitive fish was thought to be extinct for about 65 million years when one was pulled from the depths in 1938 off the coast of South Africa. Since then, several more have been caught, including some 6,000 miles from the original location.
More recently, scientists say that they believe that a reservoir 400 miles below our feet contains enough water to fill our oceans three times. If true, this suggests that our surface water actually came from within, instead of being deposited by icy comets striking Earth billions of years ago. It also makes one wonder what the planet would look like if all that water were up here instead of down there. Those who are religious might say it would look much like it did shortly after Noah built his arc--- and they might add that explains where the water came from.
Exotic species, meanwhile, provide some of the greatest--- and costliest--- of nature’s mysteries. And, as speedier transport and improved technology facilitate their spread, they will continue to do so. That’s because the consequences of their introductions can’t truly be determined until it’s too late. Yes, we can theorize based on their size, needs, breeding habitats, etc., and the niches that they filled in their native habitats.
But as we’ve learned in recent years, zebra mussels, Asian carp, and other invaders are not subject to the same limiting factors--- predation, disease, climate, habitat--- as they were in their native ecosystems. In other words, what it was there is not what it is here.
Yes, we knew that zebra mussels would filter the water in the Great Lakes. But we had no idea that this process would contribute to a resurgence in blue-green toxic algae blooms or that the shellfish would link with another invader, the round goby, to cause fish-eating birds such as loons to die of botulism poisoning. Yes, we knew that Asian carp would compete with native species for food and habitat. But we had no idea that the silver would become a serious navigation hazard on some waters because of its leaping when frightened.
Which brings us to a recent revelation by a scientist at the University of Waterloo in Canada. Her proposal turns on its head the idea that Asian carp and other exotic species require an abundance of suitable habitat to thrive and spread. And if she’s correct, that means total lockdown of the Great Lakes from its manmade connection with the Illinois River is more important than ever.
“We recently found that only 10 Asian carp are needed to establish a population in the Great Lakes,” said Kim Cuddington, an ecology professor. “But then we asked, if there are so few individuals initially, how do they find a mate and create an ecological disaster?”
The answer is “landmarking.” And it works this way: Where is it easier for you to locate bass, in a pond with one laydown or a pond with a dozen? Yes, fishing might be better overall in the latter, but that’s not what we’re talking about.
We’re talking about a “hook up” --- forgive the pun--- in a non-angling sense. Whether a lonely male is an Asian carp or a butterfly, he instinctively knows to hightail it to the nearest preferred landmark habitat--- or "hangout"--- of his species to find a mate. This strategy allows species to reproduce even when population densities are low.
"With an endangered species, if the number of landmarked sites is increased, the individuals will have a lower chance of finding a mate," said Cuddington. "By contrast, decreasing the number of landmarked sites in an effort to keep invasive species from reproducing has the opposite effect, and ensures individuals have a near certain chance of finding a mate.”
Asian carp use river water quality and flow rate as landmarks to find mates more easily than originally thought, she explained.
"For species like Asian carp, precautionary measures have to be extraordinary to prevent establishment in the Great Lakes," said Cuddington. "When we see Asian carp use landmarking, officials need to worry."
(This article appeared originally in B.A.S.S. Times.)