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Review of the Effectiveness of Recovery Activities for North Atlantic right whales


Review of the Effectiveness of Recovery Activities for North Atlantic right whales

Review of the Effectiveness of Recovery Activities for North Atlantic right whales (PDF, 1.69 MB)

Table of Contents

1. Background

In November 2016 Canada’s Oceans Protection Plan (OPP) was announced, which outlined several new initiatives aimed at addressing the threats to marine mammals in Canadian waters including the threats of contaminants, prey availability, and underwater noise. Under the OPP, the Government of Canada will take action to address the cumulative effects of shipping on marine mammals and work with partners to implement a real-time whale detection system to alert mariners of the presence of whales. As part of OPP, Fisheries and Oceans Canada (DFO) was tasked with launching a science-based review of the effectiveness of the current management and recovery actions for three at-risk whale species in Canada: the Southern Resident Killer Whale (Orcinus orca), the St. Lawrence Estuary Beluga (Delphinapterus leucas) and the North Atlantic right whale (Eubalaena glacialis). The review seeks to identify areas for immediate improvement in recovery efforts and priorities for new or enhanced actions. DFO adopted a phased approach for this review, and this document represents the first phase in that process and is focused on the recovery activities for North Atlantic right whale from a scientific perspective.

The North Atlantic right whale is considered one of the most endangered of all large whale species (Caswell et al. 1999, Kraus et al. 2005), and is federally protected under the Species at Risk Act (SARA) in Canada and the Endangered Species Act (ESA) in the United States of America (USA). Right whales throughout the Atlantic Ocean were considered a single species and first designated as endangered in 1980, and were re-assessed and confirmed as endangered in 1985 and again in 1990 (COSEWIC 2003). In 2003, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) recognised right whales in the North Atlantic as a separate wildlife species from those in the South Atlantic (Southern right whales; E. australis) and designated North Atlantic right whales as endangered (COSEWIC 2003). North Atlantic right whales were listed as an endangered species under the SARA in 2005 (COSEWIC 2013), and they are also listed as endangered under the International Union for Conservation of Nature’s (IUCN) red list of threatened species (IUCN 2008). The species was re-evaluated by COSEWIC in 2013 and once again designated endangered (COSEWIC 2013).

Historically, intense whaling greatly diminished the number of North Atlantic right whales throughout their range (Aguilar 1986). Despite being internationally protected since 1935 (IWC 2001), the population has yet to increase to more than a few hundred individuals. This is in sharp contrast to southern right whales, whose numbers were also considerably reduced due to whaling, and have since exhibited an annual population growth rate estimated at 7% (Best 1990, Cooke et al. 2001) and are listed as “least concern” under the IUCN’s red list of threatened species (IUCN 2008).

The population estimate for North Atlantic right whales was approximately 350 individuals in the mid-2000s (Kraus and Rolland, 2007). The population in 2015 was estimated to be 524 individuals based on the number of individually-identified photographed whales (Pettis and Hamilton 2016). The ‘minimum number alive population index’ (the minimum number of live whales in the population calculated from the individual sightings database) provides an estimated average population growth rate of 2.8% for the 1990-2011 period (Waring et al. 2016). However, due to a 40% decrease in the estimated calving rate since 2010 (Kraus et al. 2016), population growth rate in recent years (2012-2015) appears to be declining (Pace, 2016) and two out of the three population assessment methods demonstrate a decline in North Atlantic right whale abundance (Kraus et al. 2016 and references therein).

It has been hypothesized that the limited recovery of North Atlantic right whales may be due to decreased reproductive rates (Knowlton et al. 1994, Kraus et al. 2001), low genetic variability (Waldick et al. 2002), prey-field dynamics and reduced access to prey (Kenney 2001, Baumgartner et al. 2007, Michaud and Taggart 2007), and deleterious human activities such as vessel strikes and fishing-gear entanglement (Kraus 1990, Knowlton and Kraus 2001, Kraus et al. 2005, van der Hoop et al. 2013, Kraus et al. 2016). However, the only hypothesis that we can directly address is deleterious human activities to reduce mortalities and promote recovery.

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