The fish community has been altered by the accidental and intentional
introduction of non-native species. Let’s use the members of the historic and
present Lake Michigan food chain as an example. Historically, the planktivores
included the lake herring and several species of deep-water ciscoes. Today,
accidentally introduced species – alewife and rainbow smelt – fill their functional
niche.28 The alewife is now believed to constitute most of the biomass in
lake Michigan. The alewife was introduced to the lake when an impoundment
being used to grow them as bait fish failed in a storm and washed its contents
into the lake. The alewife succeeded because it has the ability to out feed the
native species. Alewifes and smelt are prey for intentionally introduced pacific
salmon, which now replace the native lake trout as the top fish predator. The
salmon are hatchery raised, and used to keep the alewife in check.
The same story, sometimes with different species names, is true for each
lake in the basin.
The fish community has been altered by the accidental and intentionalintroduction of non-native species. Let’s use the members of the historic andpresent Lake Michigan food chain as an example. Historically, the planktivoresincluded the lake herring and several species of deep-water ciscoes. Today,accidentally introduced species – alewife and rainbow smelt – fill their functionalniche.28 The alewife is now believed to constitute most of the biomass inlake Michigan. The alewife was introduced to the lake when an impoundmentbeing used to grow them as bait fish failed in a storm and washed its contentsinto the lake. The alewife succeeded because it has the ability to out feed thenative species. Alewifes and smelt are prey for intentionally introduced pacificsalmon, which now replace the native lake trout as the top fish predator. Thesalmon are hatchery raised, and used to keep the alewife in check.The same story, sometimes with different species names, is true for eachlake in the basin.
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