SOMETIMES the 鈥渇ew鈥� must suffer to protect the many. Tens of thousands of fish were poisoned last week in a drastic attempt to keep invasive Asian carp out of the Great Lakes.
Officials poured more than 8000 litres of the fish poison into a 9-kilometre stretch of the Chicago Sanitary and Ship Canal, which links the Mississippi river and Lake Michigan, during maintenance work on a barrier that normally keeps invaders at bay using electric shocks.
It is feared that if the voracious bighead and silver carp are not kept out, they will out-compete the native species crucial to the lakes鈥� sports and commercial fishery, worth $7 billion per year. Rotenone, derived from plant roots, enters the bloodstream of fish through their gills and inhibits cellular respiration. It is only mildly toxic to humans.
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So far only one bighead carp has been found among the thousands of dead fish removed from the canal, but authorities say carp tend to sink when poisoned. There are fears it may already be too late to keep them out, but none has yet been found on the lake side of the electric barrier.
Asian carp, which can grow to about 1.5 metres long and 50 kilograms, were introduced to aquaculture ponds in the southern US in the 1970s but escaped and have slowly made their way up the Mississippi. Michigan鈥檚 attorney general said on Monday that the state was preparing a lawsuit seeking to have the canal closed, at least temporarily, to protect its fishing and tourism industries.