51813_Sturgeon biodioversity an.PDF

Environmental Biology of Fishes48:299–309,1997,
© 1997KluwerAcademicPublishers. Printedinthe Netherlands.

The status and distribution of lake sturgeon, Acipenser fulvescens, in the

Canadian provinces of Manitoba, Ontario and Quebec: a genetic perspective

Moira M.Ferguson^1 &George A.Duckworth^2

2 Department of Zoology and Institute of Ichthyology, University of Guelph, Guelph, Ontario NlG 2WI, Canada
Ontario Ministry of Natural Resources, Northwest Region, 140–4th Ave., Cochrane, Ontario POL 1 CO, Canada

Received18.11.1994 Accepted8.4.1996

1

Key words:postglacial recolonization, anthropogenic influences, fish, Acipenseridae, conservation

Synopsis

Genetic analysis of mitochondrial DNA sequence variation indicates that most of a sample of 396 lake stur-

geon,Acipenser fulvescens,from the northern part of their range belonged to either one of two haplotypes.

The vast majority of fish from the Great Lakes/St. Lawrence and Mississippi drainages were of a single haplo-

type while those from the Hudson/James Bay were composed of both haplotypes. This haplotypic distribution

suggests that fish from one refugium (possibly Missourian) recolonized the Hudson-James Bay drainage while

those from a second (possibly Mississippian) recolonized the Laurentian Great Lakes and St. Lawrence Riv-

er. Lake sturgeon still inhabit much of their native postglacial distribution in Manitoba, Ontario and Quebec.

However, the stresses of commercial overexploitation and habitat alteration, usually through hydroelectric

dam construction and operation, have either singly or in tandem brought about the reduction, if not extirpa-

tion, of some populations within the range. The largest zone of extirpation and population reduction has

occurred in the Lake Winnipeg drainage area, which covers more than one-third of Manitoba. Other areas

where populations have been reduced to remnant levels, if not extirpated, include the lower Laurentian Great

Lakes of Lake Ontario and Lake Erie. In northern Ontario, lake sturgeon populations whose riverine habitats

have been fragmented by two or more dams are substantially reduced from their former levels. In Quebec,

more attention has been paid to limiting the exploitive stresses on lake sturgeon populations. Combination of

the genetic and status data suggests that both northern and southern populations of lake sturgeon (possibly

from two glacial refugia) have been impacted severely from anthropogenic influences.

Introduction

The lake sturgeon, Acipenser fulvescens, is one of

the most widely distributed members of the North

American fish fauna. Its native range includes three

major watersheds: the Laurentian Great Lakes,

Hudson-James Bay, and the Mississippi River southern Arkansas.

(Houston 1987). The Canadian distribution of lake

sturgeon includes the five provinces of Alberta,

Saskatchewan, Manitoba, Ontario, and Quebec. It

exists as far west as Edmonton on the North Sas-

katchewan River, as far east as St. Roch de Aul-

naires on the St. Lawrence River, as far north as the

Seal River, a tributary on the west coast of Hudson

Bay, and as far south as the main Mississippi River

and in most of its larger tributaries southward to

The current distribution of lake sturgeon has

been impacted by historical processes such as post-

glacial recolonization of the northern part of the