Canadian Science Advisory Secretariat (CSAS) Research Document 2015/024 Maritimes Region Overview of 2013 Bay of Fundy Striped Bass Biology and General Status R.G. Bradford1, E.A. Halfyard1, T. Hayman2, and P. LeBlanc1 Fisheries and Oceans Canada 1Science Branch, Maritimes Region 2Species at Risk Management Division P.O. Box 1006 Dartmouth, Nova Scotia, B2Y 4A2 July 2015 Foreword This series documents the scientific basis for the evaluation of aquatic resources and ecosystems in Canada. As such, it addresses the issues of the day in the time frames required and the documents it contains are not intended as definitive statements on the subjects addressed but rather as progress reports on ongoing investigations. Research documents are produced in the official language in which they are provided to the Secretariat. Published by: Fisheries and Oceans Canada Canadian Science Advisory Secretariat 200 Kent Street Ottawa ON K1A 0E6 http://www.dfo-mpo.gc.ca/csas-sccs/ [email protected] © Her Majesty the Queen in Right of Canada, 2015 ISSN 1919-5044 Correct citation for this publication: Bradford, R.G., Halfyard, E.A., Hayman, T., and LeBlanc, P. 2015. Overview of 2013 Bay of Fundy Striped Bass Biology and General Status. DFO Can. Sci. Advis. Sec. Res. Doc. 2015/024. iv + 36 p. TABLE OF CONTENTS ABSTRACT ................................................................................................................................ iv RÉSUMÉ ................................................................................................................................... iv INTRODUCTION ........................................................................................................................1 BAY OF FUNDY STRIPED BASS LIFE HISTORY CHARACTERISTICS ...................................2 GENERAL DESCRIPTION ..................................................................................................... 2 SHUBENACADIE RIVER POPULATION ............................................................................... 3 EARLY-LIFE HISTORY .......................................................................................................... 4 SAINT JOHN AND ANNAPOLIS RIVERS POPULATIONS .................................................... 4 ABUNDANCE AND DISTRIBUTION ...........................................................................................5 SHUBENACADIE RIVER POPULATION ............................................................................... 5 Adult Abundance ................................................................................................................ 5 Juvenile Abundance ........................................................................................................... 6 Distribution ......................................................................................................................... 6 Saint John River Population ............................................................................................... 7 Annapolis River Population ................................................................................................ 7 HABITAT .....................................................................................................................................8 SPAWNING HABITAT ........................................................................................................... 8 Locations ............................................................................................................................ 8 Features ............................................................................................................................. 9 Attributes ............................................................................................................................ 9 REARING HABITAT ............................................................................................................... 9 Locations ............................................................................................................................ 9 Features ............................................................................................................................10 Attributes ...........................................................................................................................10 FORAGING ...........................................................................................................................10 WINTER HABITAT ................................................................................................................10 Locations ...........................................................................................................................10 Features ............................................................................................................................11 Attributes ...........................................................................................................................11 POPULATION AND DISTRIBUTION TARGETS FOR RECOVERY .......................................... 11 ABUNDANCE TARGETS ......................................................................................................11 DISTRIBUTION TARGETS ...................................................................................................11 RESIDENCE REQUIREMENTS ...............................................................................................11 THREATS AND LIMITING FACTORS ......................................................................................12 SHUBENACADIE RIVER POPULATION ..............................................................................12 ANNAPOLIS RIVER POPULATION ......................................................................................12 SAINT JOHN RIVER POPULATION .....................................................................................13 BAY OF FUNDY STRIPED BASS DESIGNATABLE UNIT ....................................................14 Direct Mortality ..................................................................................................................14 Water Quantity ..................................................................................................................15 Water Quality ....................................................................................................................15 Impacts on Habitat ............................................................................................................15 REFERENCES .........................................................................................................................16 TABLES ....................................................................................................................................21 FIGURES ..................................................................................................................................25 APPENDICES ...........................................................................................................................33 iii ABSTRACT Anadromous Striped Bass spawning populations occur in three of the rivers flowing to the Bay of Fundy (BoF): the Shubenacadie and Annapolis rivers, Nova Scotia, and the Saint John River, New Brunswick. The populations collectively define the BoF Striped Bass Designatable Unit (DU). The DU has been assessed as ‘at risk’ by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) on two occasions, the first in 2004 as Threatened and the second in 2012 as Endangered. Declining demographic status resulting from loss of spawning populations and unmitigated threats to extant spawning populations were the most significant factors contributing to the ‘at risk’ designations. The BoF Striped Bass DU is presently under consideration for listing as Endangered on Schedule 1 of Canada’s Species at Risk Act (SARA). A Recovery Potential Assessment completed in 2006 in response to the Threatened designation is, therefore, in need of an update. The aim of this document is to synthesize and to update where possible information relevant to the Recovery Potential Assessment. The information is presented both for the individual spawning populations that define the DU and for the DU as a whole. Aperçu de la biologie et de la situation générale du bar rayé de la baie de Fundy en 2013 RÉSUMÉ On trouve les populations de bars rayés reproducteurs anadromes dans trois des rivières qui se jettent dans la baie de Fundy : les rivières Shubéanacadie et Annapolis, en Nouvelle-Écosse, et le fleuve Saint-Jean, au Nouveau-Brunswick. Les populations définissent collectivement l'unité désignable (UD) du bar rayé de la baie de Fundy. Par suite d'une évaluation, l'UD a été désignée comme étant « en péril » par le Comité sur la situation des espèces en péril au Canada (COSEPAC) à deux reprises, la première en tant qu'espèce menacée en 2004 et la deuxième en tant qu'espèce en voie de disparition en 2012. La situation démographique en déclin du fait de la disparition des populations reproductrices et les menaces non atténuées pesant sur les populations reproductrices qui subsistent sont les principaux facteurs qui ont contribué à ce que l'espèce soit désignée comme étant « en péril ». L'UD du bar rayé de la baie de Fundy est actuellement à l'étude en vue d'être inscrite comme espèce en voie de disparition à l'annexe 1 de la Loi sur les espèces en péril (LEP) du Canada. Par conséquent, il faut mettre à jour