Taxonomy, Distribution, and Conservation of Lampreys in Canada

摘要

There are 11 lamprey species in Canada: Vancouver lamprey Entosphenus macrostomus (formerly Lampetra macrostoma), Pacific lamprey Entosphenus tridentatus (formerly Lampetra tridentata), chestnut lamprey Ichthyomyzon castaneus, northern brook lamprey Ichthyomyzon fossor, silver lamprey Ichthtyo-myzon unicuspis, river lamprey Lampetra ayresii, western brook lamprey Lampetra richardsoni, Alaskan brook lamprey Lethenteron alaskense, American brook lamprey Lethenteron appendix (formerly Lampetra appendix), Arctic lamprey Lethenteron camtschaticum (formerly Lampetra camtschatica), and sea lamprey Petro-myzon marinus. Entosphenus and Lethenteron were previously synonymized with Lampetra, but Nelson (2006) recognized these as three distinct genera. Conservation status has been assessed in only five species and in two of these (western brook lamprey and chestnut lamprey), only for portions of their Canadian population. The 2007 Committee on the Status of Endangered Wildlife in Canada list indicates that theenigmatic population of western brook lamprey in Morrison Creek, British Columbia, is endangered; the Vancouver lamprey in British Columbia is threatened; the chestnut lamprey in Saskatchewan and Manitoba is special concern; the northern brook lamprey in Manitoba, Ontario, and Quebec is of special concern in the latter two provinces and data deficient in the former; and the Alaskan brook lamprey in the Northwest Territories is data deficient. The threats to the four species at risk were collectively related to habitat degradation and loss, sensitivity to a catastrophic event, and sensitivity to lampricide used to control the invasive sea lamprey in the Great Lakes basin. Despite much lamprey work being conducted in the past decade, there still remaina number of knowledge gaps. These gaps include unequivocal evidence as to whether parasitic and nonparasitic members of a paired species should be considered distinct species and information on the distribution and population sizes and trends of the native lamprey species.