C S A S S C C S Canadian Science Advisory Secretariat Secrétariat canadien de consultation scientifique Research Document 2010/117 Document de recherche 2010/117 Information in Support of a Recovery L’information a l’appui de l’évaluation Potential Assessment of Atlantic Mud- du potentiel de rétablissement de la piddock (Barnea truncata) in Canada pholade tronquée (Barnea truncata) au Canada Andrew Hebda Nova Scotia Museum of Natural History 1747 Summer Street Halifax, Nova Scotia B3H 3A6 This series documents the scientific basis for the La présente série documente les fondements evaluation of aquatic resources and ecosystems in scientifiques des évaluations des ressources et Canada. As such, it addresses the issues of the des écosystèmes aquatiques du Canada. Elle day in the time frames required and the traite des problèmes courants selon les documents it contains are not intended as échéanciers dictés. Les documents qu’elle definitive statements on the subjects addressed contient ne doivent pas être considérés comme but rather as progress reports on ongoing des énoncés définitifs sur les sujets traités, mais investigations. plutôt comme des rapports d’étape sur les études en cours. Research documents are produced in the official Les documents de recherche sont publiés dans language in which they are provided to the la langue officielle utilisée dans le manuscrit Secretariat. envoyé au Secrétariat. This document is available on the Internet at: Ce document est disponible sur l’Internet à: http://www.dfo-mpo.gc.ca/csas/ ISSN 1499-3848 (Printed / Imprimé) ISSN 1919-5044 (Online / En ligne) © Her Majesty the Queen in Right of Canada, 2011 © Sa Majesté la Reine du Chef du Canada, 2011 Maritimes Region Assessment of Atlantic Mud-piddock in Canada TABLE OF CONTENTS ABSTRACT / RÉSUMÉ.............................................................................................................. v SPECIES SUMMARY................................................................................................................. 1 BACKGROUND.......................................................................................................................... 1 TAXONOMY ............................................................................................................................... 2 DESCRIPTION ........................................................................................................................... 2 BASIC BIOLOGY ....................................................................................................................... 5 Food and Feeding ................................................................................................................. 7 Salinity Tolerance .................................................................................................................. 7 Dispersal................................................................................................................................ 8 Habitat Requirements............................................................................................................10 STATUS AND TRENDS .............................................................................................................12 Distribution – Range ..............................................................................................................12 North-Eastern United States ............................................................................................13 Canadian Distribution.......................................................................................................13 Abundance ............................................................................................................................14 Recent Trajectory for Species Abundance and Range .........................................................17 Recent Life History Parameters.............................................................................................17 Natural Mortality ...............................................................................................................17 Recruitment......................................................................................................................19 HABITAT CONSIDERATIONS...................................................................................................19 Adults.....................................................................................................................................19 Water................................................................................................................................19 Substrate..........................................................................................................................20 Larvae....................................................................................................................................20 Water................................................................................................................................20 Substrate..........................................................................................................................20 Spatial Extent of Areas that are Likely to have These Properties .........................................20 Spatial Constraints ................................................................................................................21 Supply of Habitat Meeting Demands .....................................................................................21 Habitat Allocation Options .....................................................................................................21 RESIDENCE REQUIREMENTS .................................................................................................21 THREATS ...................................................................................................................................21 Temperature Change ............................................................................................................22 Ice Movement in Late Winter.................................................................................................22 Increased Frequency and Severity of Storm Events .............................................................22 Installation of Water Control Structures or In-Stream Generators.........................................22 Mining of Minerals in River and Basin Sediments .................................................................22 Surficial Drainage from Adjoining Watersheds ......................................................................23 Excavation of Salt Domes for Liquified Gas Storage.............................................................23 Bulk Petroleum Movement in the Gulf of Maine ....................................................................23 iii Maritimes Region Assessment of Atlantic Mud-piddock in Canada RECOVERY OBJECTIVES ........................................................................................................23 RESEARCH AND ANALYSIS REQUIRED................................................................................24 CONCLUSIONS .........................................................................................................................24 REFERENCES CITED................................................................................................................24 TABLES......................................................................................................................................28 iv Maritimes Region Assessment of Atlantic Mud-piddock in Canada Correct citation for this publication: Hebda, A. 2011. Information in Support of a Recovery Potential Assessment of Atlantic Mud- piddock (Barnea truncata) in Canada. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/117: vi + 30 p. ABSTRACT The Atlantic Mud-piddock (Barnea truncata) was listed as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in November, 2009. The designation was due to its’ small, disjunct Canadian distribution, entirely dependent on a single geological formation, the red-mudstone facies within the Minas Basin, Nova Scotia. This document provides the information and scientific advice required to meet the various requirements of the Species at Risk Act (SARA), such as deciding whether or not to add the Atlantic Mud-piddock to Schedule 1 under SARA, developing a Recovery Strategy if it is listed, and informing decisions on authorization to carry out activities that would otherwise violate the SARA provisions. This Research Document describes the current state of knowledge of the biology, distribution, ecology, habitat requirement and threats to the Atlantic Mud-piddock. It outlines the protection under current legislation, and what additional protection would be afforded if listed under SARA. RÉSUMÉ La pholade tronquée (Barnea truncata) a été évaluée en novembre 2009 par le Comité sur la situation des espèces en péril au Canada (COSEPAC) comme étant une espèce menacée. Cette décision était fondée sur le fait qu’il n’existe au Canada qu’une petite population isolée de cette espèce vivant exclusivement sur un seul type de formation géologique, soit les mudstones rouges du bassin Minas, en Nouvelle-Écosse. Le présent document contient l’information et l’avis scientifique nécessaires pour satisfaire aux diverses exigences de la Loi sur les espèces en péril (LEP), par exemple pour déterminer s’il convient