Records of harbour porpoise (Phocoena phocoena) in the mouth of the Douro River (northern Portugal) with presence of an anomalous white individual

Ágatha Gil,Ana M Correia,Isabel Sousa-Pinto

doi:10.1186/s41200-018-0160-3

Abstract

BackgroundHarbour porpoise (Phocoena phocoena) is listed under the Annex II of the European Habitats Directive (Directive 92/43/CEE) and Member States are required to designate special areas of conservation to protect their populations. Although harbour porpoise distribution in the Iberian Peninsula has been described, the mouth of the Douro River was never reported as part of its range of distribution.MethodsObservations from a pier in the mouth of the Douro were carried out to monitor the presence of the harbour porpoises. A monthly measure of sightings per unit of effort was calculated. Information on the sightings, group sizes and records of the white individual is presented.ResultsTwenty six surveys were performed resulting in 22 sightings with group size varying from one to three animals. The white individual was sighted 12 times and recorded both in photographs and video. July was the month with the lowest number of sightings per unit of effort (SPUE), while October had the highest SPUE.ConclusionsEvidences, such as the presence of an easily recognizable white individual and the reports from local sea-users suggest a degree of site fidelity from this group of harbour porpoises in the mouth of the Douro River. However, further studies are needed to support the effective management and conservation of this group.

Highlights

Harbour porpoise (Phocoena phocoena) is listed under the Annex II of the European Habitats Directive (Directive 92/43/CEE) and Member States are required to designate special areas of conservation to protect their populations
A dedicated monitoring programme running from July to October 2017 was planned, in order to assess the presence of harbour porpoises (Phocoena phocoena) in the mouth of the Douro River
None of them were classified as the white individual, which suggests the group has, at least, four harbour porpoises

Summary

Introduction

Harbour porpoise (Phocoena phocoena) is listed under the Annex II of the European Habitats Directive (Directive 92/43/CEE) and Member States are required to designate special areas of conservation to protect their populations. The harbour porpoise (Phocoena phocoena) is the smallest cetacean in the northwest European continental shelf waters with a wide geographic distribution in the northern hemisphere (Andersen 2003) This cetacean is considered a species of concern according to several international organizations and agreements such as: International Union for Conservation of Nature (IUCN)); Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas (ASCOBANS); the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS); International Council for the Exploration of the Sea (ICES); International Whaling Commission (IWC) and is listed under the Annex II of the European Habitats Directive (Directive 92/43/CEE). In this region, outdated and scarce data on human activities and porpoise distribution prevents the proper identification of threats and risk assessment (Sequeira 1996)

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