51813_Sturgeon biodioversity an.PDF

Environmental Biology of Fishes 48:221–230,1997.
© 1997Kluwev Academic Publishers. Printed in the Netherlands.

Species structure, contemporary distribution and status of the Siberian

sturgeon,Acipenser baerii

Georgii I. Ruban
A.N.Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, 117071, Russia

Received 2.8.1994 Accepted 12.3.1996

Key words:Ob River, Lena River, Yenisey River, Kolyma River, Indigirka River, Lake Baikal, taxonomy,

subspecies, range, pollution, histological anomalies

Synopsis

A detailed analysis of the historical and contemporary range of the Siberian sturgeon,Acipenser baerii,shows

that the contemporary status of its populations and forms can be described as threatened or endangered.

Recently, the abundance of the nominal subspecies, A.b. baerii, which inhabits mainly the Ob River basin,

decreased sharply. Due to construction of hydroelectric dams, up to 40% of the spawning grounds became

inaccessible for migrating sturgeon of this subspecies. The Lake Baikal subspecies, A. baerii baicalensis, is

extremely rare and was included in the Russian Federation Red Data Book in 1983. The abundance of the east

Siberian subspecies,A.baerii stenorrhynchus,inhabiting the basins of the east Siberia rivers, has also signif-

icantly decreased during the last few years. Its range in the Yenisey and Lena River basins is gradually being

reduced. Gametogenesis is anomalous in a high number of females from all populations of this subspecies (in

the Kolyma and Indigirka river stocks 80–100% of females were anomalous in 1987–1989). These anomalies

seem to be caused by high levels of water pollution.

Introduction

The range of Siberian sturgeon, Acipenser baerii, is

very large. However, because the rivers it inhabits

are not easily accessible to researchers (it lives in

practically all large Siberian rivers, many of which

are difficult to reach) and because of its low abun-

dance, studies of the Siberian sturgeon are few. Re-

cent intensive anthropogenic impact on the north

Siberian water bodies (fisheries, construction of

dams, and pollution) makes it necessary to evaluate

the contemporary status of different forms and

populations of this species. Moreover, until recent-

ly, the populations of A.baeriifrom the northeast-

ern part of its range were little known and were not

included in the recent review on this species (Soko-

lov & Vasiliev 1989). This paper offers a revision of

the information on the range of A. baerii, including

its taxonomy, and evaluation of the contemporary

status of different subspecies and populations. The

northeastern populations are the primary focus.

Historic and contemporary range of Acipenser

baerii

The range of the Siberian sturgeon extends in the

meridional direction from 73–74°n.1. (Lena River,

Ob Bay) to 48–49°n. 1.(Chernyi Irtysh and Selenga

rivers) (Dryagin 1948a, Votinov et al. 1975), and in

the longitudinal direction from the Ob River basin

to the Kolyma River, up to 97° (Dryagin 1948a). The