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EXOTICS [Compatibility Mode]

EXOTICS [Compatibility Mode] - Introduced Fishes in Marine...

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Introduced Fishes in Marine Systems and Inland Seas A major threat to marine biodiversity Number of marine & estuarine introductions is small compared to freshwater introductions exceeded 120 spp in 1991 and growing many intentional introductions made to enhance fisheries many inadvertent introductions were the result of canal construction or ballast transport Misnomer: Inadvertent Introductions Designation implies accidental or unintentional Really means ‘not turning the mind to a matter’ Inattentive Many ongoing introductions could be avoided if responsible parties did not stick their heads in the sand Introductions are now negligent rather than accidental because we know how and why they happen & potential neg consequences Ballast-water transport is a 20th century phenomenon Inadvertent introductions via shipping have been occurring for centuries Hull fouling and rock ballast transported many organisms Obscured zoogeography of inverts and probably fishes Affected community structure of many coastal ecosystems Intentional Introductions Generally to enhance fisheries Most did not establish populations did not achieve objectives had deleterious effects In several cases, introduced spp have contributed to the extinction of native fishes, especially endemic species Accurate Information is Fragmentary Many ecosystems have not been thoroughly surveyed many exotics incorrectly identified as “natives” in early surveys many exotics overlooked, especially rare and benign species Introductions to Improve Fisheries Early successes with anadromous spp Former Soviet Union 42 intros of 29 spp 11 (26%) t bli h d l l ti 11 (26%) established large populations 5 (12%) established small populations Strong negative effects on native fishes, esp endemics in closed ecosystems Introduced parasites and other inverts altered community structure and reduced fishery landings
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