Description

G. McDonald et al., editors

188 pages; color pictures

Published by American Fisheries Society

Publication date: 1998

Symposium 21

doi: https://doi.org/10.47886/9781888569087

Summary:

Early mortality syndrome (EMS) is the term now widely used to describe mortality affecting early life stages of various salmonid species in the Great Lakes and Baltic Sea. Scientists have concluded that (1) the syndrome is confined to eggs collected from wild broodstock, (2) stocks afflicted with EMS produce eggs with very low thiamine levels, and (3) mortality can be dramatically reduced by therapeutic treatments of eggs or sac fry with thiamine.

But much about EMS remains unknown. What is the precise cause of the thiamine deficiency? Why has mortality attributed to EMS risen dramatically in recent years while aquatic contaminant levels are either stable or declining? What are the similarities between the syndromes exhibited in the Great Lakes and the Baltic Sea? Is there a connection between alewife and smelt in the diet of adult salmonids and the production of thiamine-deficient broodstock and eggs?

Biologists from North America and Scandinavia gathered in 1996 to review current research on EMS with a focus on thiamine deficiency, its symptoms, its treatment, and its causes. That research is summarized in this 18-paper proceedings, which addresses methods for analyzing thiamine levels, possible causes of EMS, thiamine levels in feral fish stocks, clinical signs associated with EMS, treatment protocols for EMS, and progress toward development of a laboratory model of EMS.

EMS is more than a local problem; it is potentially global in nature because it affects fundamental biological processes such as reproduction in top predators and keystone species in several parts of the Northern Hemisphere. It is a threat to stocking programs and an impediment to restoration of self-sustaining populations in the Great Lakes, the Finger Lakes of New York, and the Baltic Sea. This book represents the first comprehensive collection of peer-reviewed literature to focus on the attributes of this important fisheries problem.

Table of Contents

Preface Reviewers Symbols and Abbreviations

Introduction and Overview of Early Life Stage Mortality D. C. Honeyfield, J. D. Fitzsimons, S. B. Brown, S. Marcquenski, and D. G. McDonald

Reproductive Disturbances in Baltic Fish: a Review L. Norrgren, P. Amcoff, H. Börjeson, and P.-O. Larsson

Thiamine and Early Mortality Syndrome in Lake Trout S. B. Brown, J. D. Fitzsimons, V. P. Palace, and L. Vandenbyllaardt

Low Astaxanthin Levels in Baltic Salmon Exhibiting the M74 Syndrome A. Pettersson and Å. Lignell

Effects of Thiamine Treatments on Survival of M74-Affected Feral Baltic Salmon P. Amcoff, H. Börjeson, R. Eriksson, and L. Norrgren

Descriptive Studies of Mortality and Morphological Disorders in Early Life Stages of Cod and Salmon Originating from the Baltic Sea G. Åkerman and L. Balk

Clinical and Pathological Studies of Baltic Salmon Suffering from Yolk Sac Fry Mortality J. Lundström, H. Börjeson, and L. Norrgren

Thiamine Analysis in Fish Tissues S. B. Brown, D. C. Honeyfield, and L. Vandenbyllaardt

Thiamine Concentrations in Feral Baltic Salmon Exhibiting the M74 Syndrome P. Amcoff, H. Börjeson, J. Lindeberg, and L. Norrgren

Thiamine Levels in Food Chains of the Great Lakes J. D. Fitzsimons, S. B. Brown, and L. Vandenbyllaardt