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Article: An isolated population of fourhorn sculpins (Myoxocephalus quadricornis, family Cottidae) in a hypersaline high arctic Canadian Lake

TitleAn isolated population of fourhorn sculpins (Myoxocephalus quadricornis, family Cottidae) in a hypersaline high arctic Canadian Lake
Authors
Keywordsmining impacts
sculpins
cephalic spines
evolution
Issue Date1995
PublisherSpringer Verlag Dordrecht. The Journal's web site is located at http://springerlink.metapress.com/openurl.asp?genre=journal&issn=0018-8158
Citation
Hydrobiologia, 1995, v. 312 n. 1, p. 27-35 How to Cite?
AbstractFreshwater sculpins probably evolved from marine ancestors which entered bodies of water such as proglacial lakes or lakes which were gradually isolated from the sea by isostatic rebound. Sculpins in fresh water lakes (Myoxocephalus thompsoni [Girard]) lack cephalic horns and live well below a depth of 10 m. Those in the sea (Myoxocephalus quadricornis [Linnaeus]) typically live above 10 m and possess a well developed set of four cephalic horns. The sculpins in Garrow Lake, North West Territories, are intermediate between the marine and fresh water forms with respect to their depth distributions and their cephalic horns (spines). As a consequence, Garrow Lake, which separated from the sea some 3000 years ago, serves as an excellent ‘laboratory’ for studying evolutionary changes in this sculpin. The age of the lake was based on carbon-14 dates of the fossil pelecypods from raised beaches around the lake and from observations of rates of isostatic rebound in the area as reported by Dickman & Ouellet 1983 and Pagé et al. 1984. During the last 3000 years, the surface waters of Garrow Lake have freshened and its sculpins have apparently adapted to this top down freshening by occupying a depth where the salinity of the lake approaches that of sea water. As a result, the sculpin population in Garrow Lake lives deeper than the sculpin population in the nearby Garrow Bay. Thus, the deeper dwelling Garrow Lake sculpins appear to be less vulnerable to avian predation than their shallow water dwelling marine ancestors. It is hypothesized that reduced avian predation of the Garrow Lake sculpin population is associated with the observed reduction in their cephalic horns which impart a certain degree of disruptive colouration and disruptive pattern outline allowing the shallow dwelling marine species to blend in with its background in a manner which appears to make it less visible to avian predators. It is unfortunate that the three thousand year old Garrow Lake sculpin population is now endangered by mine tailings entering the lake from the nearby Cominco Ltd. mine. The entire food chain of the lake appears to have been severely impacted by lead and zinc mine tailings entering Garrow Lake at a rate of 100 metric tonnes per hour.
Persistent Identifierhttp://hdl.handle.net/10722/209138
ISSN
2015 Impact Factor: 2.051
2015 SCImago Journal Rankings: 1.043

 

DC FieldValueLanguage
dc.contributor.authorDickman, MD-
dc.date.accessioned2015-03-31T07:51:53Z-
dc.date.available2015-03-31T07:51:53Z-
dc.date.issued1995-
dc.identifier.citationHydrobiologia, 1995, v. 312 n. 1, p. 27-35-
dc.identifier.issn0018-8158-
dc.identifier.urihttp://hdl.handle.net/10722/209138-
dc.description.abstractFreshwater sculpins probably evolved from marine ancestors which entered bodies of water such as proglacial lakes or lakes which were gradually isolated from the sea by isostatic rebound. Sculpins in fresh water lakes (Myoxocephalus thompsoni [Girard]) lack cephalic horns and live well below a depth of 10 m. Those in the sea (Myoxocephalus quadricornis [Linnaeus]) typically live above 10 m and possess a well developed set of four cephalic horns. The sculpins in Garrow Lake, North West Territories, are intermediate between the marine and fresh water forms with respect to their depth distributions and their cephalic horns (spines). As a consequence, Garrow Lake, which separated from the sea some 3000 years ago, serves as an excellent ‘laboratory’ for studying evolutionary changes in this sculpin. The age of the lake was based on carbon-14 dates of the fossil pelecypods from raised beaches around the lake and from observations of rates of isostatic rebound in the area as reported by Dickman & Ouellet 1983 and Pagé et al. 1984. During the last 3000 years, the surface waters of Garrow Lake have freshened and its sculpins have apparently adapted to this top down freshening by occupying a depth where the salinity of the lake approaches that of sea water. As a result, the sculpin population in Garrow Lake lives deeper than the sculpin population in the nearby Garrow Bay. Thus, the deeper dwelling Garrow Lake sculpins appear to be less vulnerable to avian predation than their shallow water dwelling marine ancestors. It is hypothesized that reduced avian predation of the Garrow Lake sculpin population is associated with the observed reduction in their cephalic horns which impart a certain degree of disruptive colouration and disruptive pattern outline allowing the shallow dwelling marine species to blend in with its background in a manner which appears to make it less visible to avian predators. It is unfortunate that the three thousand year old Garrow Lake sculpin population is now endangered by mine tailings entering the lake from the nearby Cominco Ltd. mine. The entire food chain of the lake appears to have been severely impacted by lead and zinc mine tailings entering Garrow Lake at a rate of 100 metric tonnes per hour.-
dc.languageeng-
dc.publisherSpringer Verlag Dordrecht. The Journal's web site is located at http://springerlink.metapress.com/openurl.asp?genre=journal&issn=0018-8158-
dc.relation.ispartofHydrobiologia-
dc.rightsThe original publication is available at www.springerlink.com-
dc.subjectmining impacts-
dc.subjectsculpins-
dc.subjectcephalic spines-
dc.subjectevolution-
dc.titleAn isolated population of fourhorn sculpins (Myoxocephalus quadricornis, family Cottidae) in a hypersaline high arctic Canadian Lake-
dc.typeArticle-
dc.identifier.doi10.1007/BF00018884-
dc.identifier.hkuros418-
dc.identifier.hkuros7615-
dc.identifier.volume312-
dc.identifier.issue1-
dc.identifier.spage27-
dc.identifier.epage35-
dc.publisher.placeNetherlands-

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