Study of parasites and diseases of sturgeons in Russia: a review

Russia has been known since ancient times for its rich aquatic natural resources, including the sturgeon species inhabiting many of its rivers, lakes and inland seas. Examples of the remaining richness of the fish fauna are represented in Russia by two genera of sturgeons (Huso and Acipenser) with a total of 11 species (Sokolov, 2002) as well as three species of the genus Pseudoscaphirhynchus in the Aral Sea basin (Kazakhstan) (Berg. 1948). One American species, Polyodon spathula, was introduced into Russia for aquaculture purposes (Sokolov, 2002). All sturgeon species differ in their ecology from many other native fish species not only because of their anadromy but also because of their longevity and life styles. During the past century species abundance of this valuable resource diminished at an alarming rate caused by overfishing, lack of management control, habitat alterations (e.g. hydrodam construction) and other human impacts such as industrial and domestic pollution. While yearly catches reached about 10 000 tonnes in the 1960s, the decline in the early 1990s resulted in a catch of no more than about 6500 tonnes. This downward trend has continued in recent years (Luk'yanenko et al., 1999). Because of this decline, aquaculture for ranching purposes was introduced in Russia during the second half of the twentieth century. It is obvious that this development was also accompanied by disease outbreaks, including those unknown prior to cultivation. Unfortunately, the documentation and study of prevailing diseases in sturgeons had not received much attention in the past and. therefore, our understanding of their prevalence, distribution, origin and ecological significance is fairly limited. It is therefore appropriate that intergovernmental organizations (e.g. FAO) and scientific societies (e.g. EAFP, European Association of Fish Pathologists) are urging that greater attention be given to disease problems (La Patra et al., 1999). This paper provides a brief overview of the status of knowledge on parasites and diseases in sturgeons in Russia and the former USSR, their occurrence and distribution. Although many Russian scientists have worked on and arc currently studying the disease issue, knowledge is fragmentary. This contribution is also an attempt to identify gaps and research needs in this area, particularly in Russia. One of the obvious gaps in Russian sturgeon disease research and management programmes is the lack of a sound design for a nation-wide electronic databank that could serve as a tool to monitor and analyse causes and trends in disease occurrences and overall epidemiology. Parasites and parasitic diseases occurring in natural sturgeon populations in Russia