Introduction

The rapidly increasing development of shellfish aquaculture around the world, along with an expanding market demand for fresh (live) shellfish, have escalated the need for vigilance against the spread of shellfish diseases. The risks associated with uncontrolled transfer and introduction of live aquatic organisms have long been recognised (ICES 1988), especially for finfish species which are regularly transferred from one location to another. In the last 10-20 years the frequency of shellfish transfers has also increased, due, in part, to the development of hatchery-based seed production and remote setting, as well as to increasing use of non-indigenous species in aquaculture. Concomitant with this increase in transfer has been the spread of significant shellfish diseases around the world, such as Bonamia ostreae of flat (= European, edible or Belone) oysters, Ostrea edulis from North America to France and subsequently throughout most of the Atlantic coast of Europe (Sindermann 1991).

Recognition of the correlation between shellfish transfers and disease-spread has been reflected by global development of regulations or guidelines to control live imports of shellfish (mainly molluscs and shrimps) (Sindermann 1986, ICES 1988, Anon. 1991, Brock 1992, Carey 1992, Carlton 1992, Smith 1992). In Canada, this led to the development of the National Aquatic Animal Health Program that is co-delivered by the Canadian Food Inspection Agency (legislative and regulatory lead) and Fisheries and Oceans Canada (diagnostic testing and research).

In order to have: 1) a strong scientific reference base upon which to justify the Regulations for shellfish, 2) classify the disease agents according to a level of concern, and 3) develop appropriate sampling protocols, an extensive list of shellfish diseases was compiled. Drawing upon the primary literature and other information that is often not readily available (i.e., research laboratory reports, government technical reports, and personal communications with colleagues) a comprehensive, worldwide synopsis on shellfish diseases of commercially important molluscs, echinoderms and crustaceans was developed. This synopsis was designed to be a source of basic information, including key references to pertinent literature, which could be used as part of the decision-making process in regard to concerns relevant to shellfish health issues. Also, it was created to be inclusive by incorporating shellfish species both present in and absent from Canadian waters. However, it is not the aim of this synopsis to review all of the details of each of the infectious agents nor does it include organisms described from shellfish of little or no current economic value. We refer readers to the key references listed after each summary and to volumes edited by Kinne (1983, 1990) and Sparks (1985) (see References) for an in depth review of the literature on shellfish including those that are not commercially exploited. Nevertheless, we have endeavoured to cover most organisms (pathogenic and non-pathogenic) of commercially important shellfish species in as broad a scope as possible.

This synopsis is arranged with each disease/parasite summary on its own page such that it is accessible as a single unit. All summary pages are listed in the Table of Contents and grouped firstly by shellfish host type (e.g., oysters), and within that, the parasites and pathogens are arranged according to their Category status in Canada (see Definitions of Category). Within each Category grouping, the summary pages are arranged by type (i.e. all viruses are together, as are all bacteria etc.). Thus, in the Table of Contents, known infectious diseases and parasites of oysters are listed in the subsection "Oysters" of the section entitled "Diseases and Pathogens of Mollusca". The other subsections included in the "Diseases and Pathogens of Mollusca" are: Mussels, Clams & Cockles, Scallops, and Abalone. Likewise, the "Diseases and Pathogens of Echinoderms" section includes subsections Sea Urchins and Sea Stars. The subsections of "Diseases and Pathogens of Crustacea" are Lobsters, Shrimp & Prawns, Crabs, and Crayfish. Each of these subsections encompasses infectious diseases known to affect that group. Each disease/parasite summary page is accessible via the Table of Contents and the organization pattern used in summary pages is described on a separate page (see Organization of Summaries).

Citation Information

Bower, S.M., McGladdery, S.E. (2014): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Abstract.

Date last revised: November 2014
Comments to Susan Bower