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

Effectiveness of Recovery Activities

Table of Contents

• Complete Text
• 1. Background
• 2. Objective of this Review
• 3. Sources of Information
• 4. Methods for Assessing Effectiveness of Recovery activities
• 5. Review of Recovery activities
  • 5.1. Recovery Objectives
  • 5.2. Threats
  • 5.3. Review of Recovery activities
• 6. Effectiveness of Recovery Activities
  • 6.1. Vessel Strikes
  • 6.2. Fishing-Gear Entanglements
  • 6.3. Disturbance and Habitat Reduction or Degradation
    • 6.3.1. Contaminants
    • 6.3.2. Acoustic Disturbance
    • 6.3.3. Vessel-presence disturbance
    • 6.3.4. Changes in Food Supply
• 7. Indirect Recovery Activities: Monitoring and Stewardship
• 8. Threat-Based Recommendations
  • 8.1. Vessel Strikes
  • 8.2. Fishing-Gear Entanglements
  • 8.3. Disturbance and Habitat Reduction or Degradation
  • 8.4. Required Research and Monitoring
• 9. Conclusions
• 10. Literature Cited
• Appendix A: Acronyms
• Appendix B: Defining Risk
• Appendix C: Summaries of Recovery Activities

6. Effectiveness of Recovery Activities

In the following sections, for each identified threat (Objectives 1-3) recovery activities implemented to reduce the threat are described in detail and any information available on population demography to illustrate the effectiveness of the measures is presented. As it is difficult to assess the effectiveness of individual recovery activities and their associated impacts on the population, all recovery activities for a specific threat are considered collectively to evaluate whether a specific threat has been reduced.

While Objectives 4-7 in the Recovery Strategy do not directly reduce threats to North Atlantic right whales, they are important for informing threat-based mitigation measures. The effectiveness of recovery activities implemented to more directly reduce or mitigate threats often relies on information obtained under these non-threat-based objectives. Additionally, knowledge gained through completing measures under Objectives 4-7 can be used to inform the development of new recovery activities to reduce the impacts of threats. As these objectives are not threat-based, nor directly related to recovery, a measure of their effectiveness is not possible; however, their importance for assessing recovery is further discussed in Section 7.

6.1. Vessel Strikes

Vessel strikes impact several marine species including sea turtles (Hazel et al. 2008), manatees (Laist and Shaw 2006), sharks (Speed et al. 2008), and cetaceans (Laist et al. 2001). Vessel strikes contribute to mortality of all large whale species in the Northwest Atlantic (van der Hoop et al. 2013). On a per capita basis the North Atlantic right whale is more prone to vessel strikes than all other large whale species (Vanderlaan and Taggart 2007) and vessel strikes have been documented throughout most of the North Atlantic right whale migratory range (Kraus and Rolland 2007, van der Hoop et al. 2014). Substantial conservation measures have been suggested and implemented worldwide to protect marine species from vessel collisions, and this is especially true for endangered North Atlantic right whales (e.g. Kraus et al. 2005, Laist and Shaw 2006, Panigada et al. 2006, NOAA 2008a).

Several recovery activities have been implemented in Canada and the USA to protect North Atlantic right whales from vessel strikes, including vessel re-routing and speed restrictions (Table 1). Vanderlaan et al. (2008) argues that vessel re-routing and speed restrictions are the two simplest and most practical methods to reduce the risk to whales from vessels (see Appendix B for definition of risk). The precedent setting recovery activity of amending the Traffic Separation Scheme (TSS) in the Bay of Fundy to re-route the vessels around high use North Atlantic right whale habitat was proposed to IMO in 2002 by Transport Canada. The IMO amended the TSS in 2003, which was the first time the IMO adopted a change to their regulations to protect an endangered species. This TSS amendment reduced the probability of a vessel encountering North Atlantic right whales as the previous outbound lane of the TSS required vessels to transit directly through the Grand Manan Basin North Atlantic right whale Conservation Area; an area that served to warn mariners of the presence of North Atlantic right whales. It was estimated that this change resulted in a reduction of the relative risk of a lethal vessel collision by 90% in the area where the TSS intersected the North Atlantic right whale Conservation Area and 62% throughout the entire study area (Vanderlaan et al. 2008). It was also estimated that detected mortalities attributable to vessel strikes would change from one every four years to one every 12 years in the Bay of Fundy (Vanderlaan et al. 2008).

Similar re-routing has since taken place in USA waters with two amendments to the Boston TSS (IMO 2006a, 2008a). The first amendment in 2006 rotated the TSS 12 degrees to the north to avoid large aggregations of whales. This shift was estimated to result in a 58% ^{Footnote 3} reduction in risk of vessel strikes to North Atlantic right whales (IMO 2006b). The second amendment in 2008 (IMO 2008b) narrowed the lanes to further reduce to the relative risk of a vessel strike by 11% (Merrick et al. 2007). Both amendments reduced the spatial co-occurrence between vessel activity and North Atlantic right whales.

In the North Atlantic right whale's southern calving ground off the coasts of Georgia and Florida, as well as in Cape Cod Bay, recommended voluntary, seasonal traffic routes have been advised to shift the traffic patterns away from areas frequented by North Atlantic right whales (NOAA 2006). Lagueux et al. (2011) estimated that the recommended routing in the southern calving ground would reduce the probability of a North Atlantic right whale mortality from a vessel by ~72% from the pre-implementation period and measured compliance with the recommended routes at 96% by the end of their study.

Transport Canada proposed the adoption of a recommendatory, seasonal Area to be Avoided (ATBA) in Roseway Basin to the IMO to further reduce the risk of vessel strikes through re-routing of traffic around another North Atlantic right whale high-use area (IMO 2007). On 01 May 2008, Canada implemented the ATBA seasonally (June through December). Although recommended by the IMO, this recovery activity is completely voluntary, similar to the Roseway Basin Right Whale Conservation Area (implemented in 1993) that was designed to promote awareness and education among mariners (Brown et al. 1995). The Conservation Area also advised vessels to either re-route around the area or reduce vessel speed, but there was no evidence of compliance with the voluntary recommendations (Vanderlaan et al. 2008). The Taggart Lab (Dalhousie Oceanography) implemented the Vessel and Conservation Area Transit Experiment (VACATE) to measure compliance with and efficacy of the voluntary ATBA. Within the first year of implementation compliance stabilized at 71%, resulting in a reduction of relative risk across the study area of 82% (Vanderlaan and Taggart 2009). Compliance estimation continues in the area, as does the Canadian Whale Institute's (CWI) Marine Stewardship Recognition Program (MSRP) designed to improve compliance with the ATBA through direction communication with vessel operators that transit through the area. From 2008 through 2014, annual compliance averaged at 80% resulting in a reduction in risk to North Atlantic right whales of 92% ^{Footnote 4} (Vanderlaan and Taggart, unpublished data).

An IMO-adopted ATBA in the Great South Channel was implemented in 2009 and annually in effect from the 01 April through 31 of July (IMO 2008a). Similarly to the Roseway Basin ATBA, the Great South Channel ATBA adopted by the IMO recommends that vessels re-route around the ATBA to avoid areas of North Atlantic right whale persistence. It was estimated that the ATBA would result in a 63%3 reduction in relative risk of a vessel striking a North Atlantic right whale (Merrick et al. 2007) though no estimate of compliance with the voluntary ATBA has been measured thus far.
Seasonal vessel speed restrictions in various North Atlantic right whale habitats and along their migratory pathway have also been implemented in the USA (NOAA 2008a). Speed restrictions were mandatory for all commercial vessels greater than 65 feet (~20m) long in ten spatially and temporally defined Seasonal Management Areas (SMAs, Table 2). These restrictions were implemented on the 09 December 2008 with a 5-year sunset clause that has since been removed (NOAA 2008a, 2013). Vessel speed is restricted to 10 knots (18.5 km/h) in each of the areas. Compliance with mandatory vessel speed restrictions has been low with only 24% of vessel transits within the SMAs slowing to the required 10 knots (Silber et al. 2014). However, within the first five years of implementation no vessel-struck North Atlantic right whales were found in or near (within 45 nautical miles or ~83 km) active SMAs (Laist et al. 2014).

As identified in Table 1, a number of other programs exist in Canada to alert mariners of the presence of North Atlantic right whales to reduce potential vessel strikes. A Mariner’s Guide to Whales in the Northwest Atlantic was developed to promote awareness among mariners (http://www.shipfed.ca/data/News/2014-06-27EngMarinersWhaleGuide.pdf). Smart phone apps have been developed that focus on reducing lethal vessel strikes to whales and alerting mariners of the presence of North Atlantic right whales (e.g., Whale Alert; www.whalealert.org).

A near real-time whale alert system for eastern Canada is under development by researcher at Dalhousie University. Research has been conducted to determine the receptivity of the commercial fleet to information on whale locations as an early warning system (Reimer et al. 2016). Moving forward, this alert system will be based on the Automatic Identification System (AIS) that is required on all IMO vessels >300 gross tonnage and all passenger vessels. Whale sounds detected by passive acoustic packages on ocean gliders are transmitted by satellite to a ground station and then validated by an experienced analyst. Once the sounds have been confirmed as a North Atlantic right whale the associated locations are then broadcast as an AIS message in near real time from coastal AIS stations to all AIS vessels within VHF range. An operational trial on the coast of Nova Scotia is planned for summer 2017 (Christopher Taggart, Dalhousie University, personal communication).

Mandatory and voluntary conservation measures in Canada focus on re-routing vessels around high-use habitats to decrease the likelihood of a vessel strike, whereas in the USA the focus was on mandatory speed restrictions, to slow the vessels down to reduce lethality should a strike occur, and voluntary re-routing of vessels. Many of these measures are implemented in identified critical habitats (e.g., Grand Manan Basin, Roseway Basin, Great South Channel, and Cape Cod Bay) and as a result the spatial density of vessel-strike mortality to all large whales has shifted to outside the SMAs (van der Hoop et al 2014). Unlike other large whale species, over the long term the North Atlantic right whale’s leading anthropogenic cause of death has been vessel strikes (44% of the human-induced mortalities from 1970-2009 compared with 35% for fishing-gear entanglements; van der Hoop et al. 2013). Seven North Atlantic right whale mortalities have been positively identified as vessel-strikes deaths in Atlantic Canada since 1970 (Knowlton and Kraus 2001; Moore et al. 2004, 2007; Campbell–Malone et al. 2008; Figure 1). However, no documented mortalities where the cause of death was conclusively determined to be attributable to vessel strikes have occurred in Canada since 2006 (van der Hoop et al. 2014; Pettis and Hamilton 2014, 2015, 2016). Furthermore, North Atlantic right whale vessel strike mortalities throughout Canada and the USA have significantly declined from 2.0 (2000-2006) to 0.33 per year (2007-2012; van der Hoop et al. 2014).

Overall, the recovery activities that have been implemented to reduce the risk of lethal vessel strikes to North Atlantic right whales appear to be effective in reducing observed mortalities. It is important to note; however, that changes in the reporting of vessel-strike mortalities over time are unknown. Observed increases in vessel strike mortality over the last 40 years could be a function of increased detection and reporting, although these increases also parallel increases in the number, speed, and size of vessels fleet-wide (Vanderlaan et al. 2009). Detection probabilities are spatially dependent, with offshore vessel strikes less likely to be observed compared to a whale killed closer to shore. Wherever the whales and vessels co-occur, there is the risk of lethal vessel strikes, and Canada has only implemented recovery activities to reduce risk of vessel strikes in identified critical habitat areas. As right whales travel to and from critical habitats and other areas in Atlantic Canada, they are unprotected from the threat of vessel strikes. Additional mitigation should be put in place, particularly as our understanding of North Atlantic right whale distribution and movement patterns increases and new high-use areas are identified.

6.2. Fishing-Gear Entanglements

Any cetacean has the potential to become entangled in fishing gear and van der Hoop et al. (2013) identified entanglements as the primary cause of death among all large whale species with the exception of North Atlantic right whales during the period 1970 through 2009. Unlike small cetaceans that cannot escape entangling gear, entangled baleen whales are capable of dragging gear (Clapham et al. 1999), thus fishing-gear entanglements are not necessarily lethal for large whales. Many North Atlantic right whales appear to shed gear or self-disentangle (Johnson et al. 2007) and scarring analyses show approximately 82% of the North Atlantic right whale population have indications of at least one entanglement in fishing gear (Knowlton et al. 2012). Determining mitigation measures to decrease North Atlantic right whale entanglements is challenging (Knowlton et al. 2012) as North Atlantic right whale entanglement events are rarely directly observed (Weinrick 1999). The locations, in time and space, and the mechanics of fishing-gear entanglements remain largely unknown (Johnson et al. 2007). Unless gear can be attributable to a Canadian fisher, or the entanglement event is observed in Canadian waters, entanglement events cannot be assigned spatially, nor can the resulting statistics. Even if a whale is initially observed in Canadian waters with gear attached, it does not necessarily mean the whale was entangled in Canada, and vice versa for the USA. However, as USA fisheries continue to implement gear marking, it becomes easier to rule out entangling gear from the USA.

Recovery activities related to reducing entanglements include research to increase understanding of entanglement mechanisms, monitoring activities to identify when whales are present in areas and voluntary mitigation measures (Table 1). In the USA numerous mitigation measures have also been implemented both at the state and federal level (Table 3). The Canadian government, however, has yet to implement policies or regulations to reduce cetacean entanglements in fishing gear, including mitigation measures specifically for North Atlantic right whales.

The regulations that have been implemented in the USA to reduce large-whale interactions with commercial fisheries have aimed to reduce both lethal and non-lethal entanglements (Pace et al. 2014) mainly through gear modifications and select fishing closures (Table 3). Gear marking has also been implemented to gather information on the types and parts of gear involved in large-whale entanglements. Gear modifications include buoy line weak links, and net panel weak links with anchoring system, restriction of the number of buoy lines, and the implementation of broad-based sinking groundlines (Table 3). Weak links are hypothesized to increase the likelihood of self-disentanglement and sinking groundlines are hypothesized to reduce the probability of entanglement, but this has yet to be confirmed through quantitative analysis. Mandatory spatiotemporal closures have also been implemented in the USA, both in critical habitats and dynamic areas around observed aggregations of North Atlantic right whales. These fishing closures may reduce the threat of North Atlantic right whale fishing-gear entanglements. However, it is difficult to assess the effectiveness of these closures due to a paucity of information regarding compliance.

There is one example of fishery exclusion in Canadian waters to reduce the entanglement risk of North Atlantic right whales. An exploratory whelk fishery was excluded from Roseway Basin to ensure trap gear did not entangle North Atlantic right whales in this critical habitat (DFO 2016b).

In Canada, two studies have been undertaken to evaluate the risk to North Atlantic right whales from fishing gear entanglements (Vanderlaan et al. 2011, Brillant et al. 2017). Both studies identify possible spatiotemporal closure as an efficient measure to reduce the probability of North Atlantic right whale fishing-gear entanglements. Brillant et al. (2017) estimated that a 30% reduction in encounter probability between North Atlantic right whales and fishing gear would prevent the death of two North Atlantic right whales every three years and as many as 32 fewer entanglements annually. These studies have not yet been used to inform policy or to implement mitigation or recovery activities to reduce the risk of lethal fishing gear entanglements of North Atlantic right whales. A third study is underway to identify additional priority areas on which to focus efforts for reducing North Atlantic right whale entanglements. DFO will examine the potential risk of lethal entanglements to North Atlantic right whales on the Scotia Shelf using Species Distributions Models (Gomez et al. 2017) to predict North Atlantic right whale suitable habitat and areas of co-occurrence with fishing activities.

Brillant and Trippel (2010) examined contemporary trap settings used by lobster fishery in the Bay of Fundy and suggested that groundlines may not contribute to the entangling factor of the gear due to the groundlines remaining below three meters; which is the hypothesized elevation that could entangle North Atlantic right whales. Validation of these results is required to verify the hypothesized elevation for entanglement, and to ensure that groundline elevation is consistently low across fishers (only two captains were included in the study), the amount of gear deployed, location, and season.

Voluntary standard practices have been established for the Scotia-Fundy Fixed Gear groundfish fishery as well as the lobster fishery in Lobster Fishing Areas (LFAs) 33, 34 (southwest Nova Scotia) and 41 (offshore area). The standard practices provide guidelines for the maximum lengths of endlines, trail/ground lines, and gangions, the use of sinking or neutrally buoyant lines, as well as best operating practices, such as avoiding setting and retrieving gear when whales are present in the area and reporting protocols if an entangled whale is observed. Although these guidelines have been established, there is currently no measure of their effectiveness in reducing the risk of a fishing-gear entanglement. Furthermore, there is no measure of compliance with recommended procedures. It is therefore unknown if these voluntary standard practices are actually implemented or effective.

The Grand Manan Fisherman's Association that operates in the Bay of Fundy (LFAs 36, 37, and 38), in partnership with DFO, conducts aerial surveys at the beginning of the lobster season in early November and fishers are instructed not to deploy or haul gear in the presence of North Atlantic right whales. These surveys have been operational since 2006 and can result in the delay of the fishing season. These data have not been examined to assess whether North Atlantic right whale presence continues into the start of the lobster fishing season and warrants further mitigation. 

The Grand Manan Whale and Seabird Research Station (GMWSRS) in collaboration with local fishers has developed a herring weir release manual to help weir operators release marine mammals, including North Atlantic right whales, with minimal damage to both the gear and the mammals. This recovery activity would be effective in reducing injury and mortalities to right whales entrapped in fishing weirs.

In Atlantic Canada, Quebec, and in the USA, regional response networks are in place to respond to marine mammals that are dead or in distress. These networks provide 24-hour hotlines, coordinate response among multiple partners, and their contact information is widely distributed to fishers and coastal communities. DFO's national Marine Mammal Response Program (MMRP) supports responses to marine-mammal incidents, including North Atlantic right whales entangled in fishing gear. This program also provides training for Conservation and Protection (C&P) Officers and provides resources and equipment in support of incident response in Atlantic Canada. C&P officers also conduct aerial surveys to verify North Atlantic right whale sightings and respond to reports of entangled or stranded whales. The Campobello Whale Rescue Team, a group of volunteers, is on call to lead disentanglement efforts in Bay of Fundy and have responded to over 20 cases of whales in distress. The Marine Animal Response Society (MARS) is a charitable organisation dedicated to the conservation of marine animals and also responds to whales in distress throughout the Maritime Provinces. In Quebec, the Marine Mammal Emergency Response Network, which includes representatives from DFO, Parks Canada, and several non-government organizations, also responds to whales in distress throughout the Estuary and Gulf of St. Lawrence.

DFO and various non-government agencies, including World Wildlife Fund Canada (WWF), CWI, the Canadian Wildlife Federation (CWF), and GMWSRS continue to work with the fishing industry and coastal communities to educate people and provide information regarding species at risk, including the North Atlantic right whale, the threats they face and information on preventing fishing-gear entanglements as well as what to do if a whale is in distress or dead. However, marine education programs were deemed ineffective at reducing vessel strikes due to visibility constraints and the ability and/or willingness of mariners to follow precautionary advice (IMO 1999). It is difficult to assess the effectiveness of these indirect programs in reducing the threat of fishing gear.

There are two primary ways to directly reduce the risk and threat of fishing-gear entanglements to whales: 1) reduce the probability of a whale becoming entangled in the gear; and 2) reduce the probability of lethality, injury, or decreased fitness when an entanglement does occur. To reduce the probability of a whale becoming entangled in gear, i.e., preventing an entanglement, the amount of gear in the water at times and in areas where the whales are present must be decreased. This could be achieved through spatiotemporal-fishing closures, or ropeless fishing. To decrease the probability of lethality or injury, the breaking strength of ropes should be decreased to allow for whales to self-disentangle or for easier disentanglement by teams trying to free a whale from gear.

The North Atlantic right whale proposed Action Plan (DFO 2016a) focusses on fishery interactions; however, it does not "prescribe specific type of mitigation measures (voluntary or regulatory) needed to reduce the risk of entanglements". It does identify that specific future mitigation measures will rely on several other activities listed in the Action Plan, including conducting spatial analyses of entanglement risk associated with fishing gear. A total of 22 recovery activities are identified in the Action Plan, only three of which can directly reduce North Atlantic right whale entanglements (Table 4). Many of the activities are essential for informing potential policies, and thus indirectly contribute to North Atlantic right whale recovery. As the recovery activities listed in the Action Plan are broad in scope and mainly make indirect contributions to recovery, it is not possible at this time to assess the effectiveness of the proposed recovery activities.

Assessing the effectiveness of individual mitigation activities aimed at reducing the risk of entanglement to North Atlantic right whales from fishing gear is not possible. However, when examining the North Atlantic right whale population and interactions with fishing gear, it becomes clear that the measures implemented thus far have been ineffective at reducing the number of North Atlantic right whale entanglements. Between 2009 and 2013 an annual average of 4.3 North Atlantic right whales were killed by human activities, in both Canada and the USA, a level much higher than the Potential Biological Removal (PBR) ^{Footnote 5} level of one North Atlantic right whale (Waring et al. 2016). Of 24 records of mortality and serious injury from 2009 through 2013 (both from USA and Canada) 18 were attributable to fishing-gear entanglements (Waring et al. 2016). The average proportion of North Atlantic right whales with newly detected scars each year attributable to fishing gear has not significantly increased over the period of 1980 through 2009; however, a significant increase in the number of serious entanglements (deep wounds or whales carrying gear) over the same period was documented (Knowlton et al. 2012). Furthermore, there was a significant increase in the number of whales carrying gear that was attributed to an increasing difficulty for the whales to free themselves completely of gear (Knowlton et al. 2012). No reduction of serious or lethal entanglements of large whales, including the North Atlantic right whales, has been observed since North Atlantic right whales were listed as endangered in 2005 under SARA (Knowlton et al. 2012; van der Hoop et al. 2013; Pace et al. 2014).

Disentanglement response continues to be an option to reduce the risk of lethal fishing-gear entanglements until effective preventative measures are developed and implemented (Moore et al. 2013). However, several factors contribute to limiting the effectiveness of disentanglement in reducing serious injury and harm to entangled animals. The time between an entanglement occurring and the first observation of the entangled whale is typically unknown and further delays for disentanglement response may be caused by the location of the entangled whale, relaying the information to the proper authorities, and the disentanglement team finding the whale again. The location of the disentanglement team and the weather will also contribute to the amount of time a North Atlantic right whale is entangled. While entangled, a North Atlantic right whale has increased drag on its body because of the attached gear (van der Hoop et al. 2013) that will slowly reduce energy stores as they require ~2.2 Í1010 J more energy to swim and feed (van der Hoop et al. 2016). Furthermore, the most common point of attachment in North Atlantic right whales is the head region (Johnson et al. 2005), where the entangling rope often disrupts the baleen resulting in reduced feeding efficiency (Moore and van der Hoop 2012). The energy required to overcome the drag of the gear and the possibility for decreased feeding efficiency significantly contributes to the emaciation that is commonly seen with chronic entanglements (Cassoff et al. 2011). Lacerations and resulting infections are another cause of death in entangled whales as they can have severe tissue and bone damage (Moore and van der Hoop 2012). The length of the time whales are entangled can be years (Moore et al. 2013) and on average it can take six months for an entangled whale to die (Moore et al. 2006). Even if the disentanglement team locates the entangled whale and attempts disentanglement, there is a low probability of success. In a study of 53 North Atlantic right whale entanglements between 1995 and 2008 only 40% of the cases resulted in successful disentanglement (Robbins et al. 2015). Furthermore, sub-lethal entanglements can contribute to declining health and reproductive failure long after the whale is disentangled (Rolland et al. 2016; van der Hoop et al. 2016, 2017). The effectiveness of disentanglement efforts for reducing the threat of entanglement is thus limited. To ensure a healthy population of North Atlantic right whales, entanglement events should be prevented rather than relying on reacting to observed entangled whales and attempting disentanglements as the primary means of reducing the threat. Prevention rather than reaction is required for North Atlantic right whale recovery.

6.3. Disturbance and Habitat Reduction or Degradation

Disturbance and habitat reduction and/or degradation have been identified as a threat to North Atlantic right whales in the Recovery Strategy (DFO 2014). Contaminants, acoustic disturbance, vessel presence, and changes in food supply, have been identified as the main contributors to disturbance and habitat reduction or degradation. The effects of various types of degradation could be instantaneous or cumulative, or both, and it is extremely difficult, and in some cases not possible, to document these effects using empirical data.

Mortalities due to human activities are well documented (e.g., Moore et al. 2004; Cassoff et al. 2011, van der Hoop et al. 2013); however, attributing sub-lethal effects of disturbance to anthropogenic activities is much more difficult (Rolland et al. 2016). It is also challenging to distinguish and quantify the relative impact of different factors, both natural and anthropogenic, on the health and vital rates of North Atlantic right whales (Kraus and Rolland 2007). As it is difficult to measure the response of the population or of individuals to the impacts of habitat loss, pollutants, acoustic disturbance, or climate change (Kraus and Rolland 2007), measuring the effectiveness of recovery activities addressing disturbance and habitat degradation (Sections 6.3.1-6.3.4) will be extremely difficult.

Contaminants, acoustic disturbance, vessel presence, and changes in food supply, are unlikely to result directly in the death of individuals although these threats have implications for the health of North Atlantic right whales. North Atlantic right whale health can be considered to assess the effectiveness of recovery activities that address these threats and indicate that the recovery activities listed below have not been effective, acknowledging that sub-lethal vessel strikes and fishing-gear entanglements will also affect the health of an individual. The annual average estimated health scores of all demographic groups in the population has declined over the period 1980 through 2008 (Rolland et al. 2016), although it was not determined if this observed decline was statistically significant.

6.3.1. Contaminants

Compared to all other wildlife worldwide, marine mammals are subject to the highest levels of environmental contaminants, some of which may suppress their immune function (Desforges et al. 2016). Contaminants and pollutants have been measured in North Atlantic right whales; however, the effects are generally unknown and causal links between health and reproduction have not been identified (Kraus and Rolland 2007). There have been a few studies on North Atlantic right whales and organochlorine and metal contaminants (Woodley et al. 1991; O'Shea et al. 1994; Montie et al. 2010). O'Shea et al. (1994) concluded that there was no definite basis for concluding that pollutants reviewed affected baleen whale populations, and research and management priorities should focus on reducing anthropogenic mortalities. Prohibition and/or reductions of some contaminants have been implemented under programs unrelated to Species at Risk species including the Prohibition of Certain Toxic Substances Regulations, 2012 (Canada Gazette 2016), Products Containing Mercury Regulations (Canada Gazette 2014), and PCB Regulations, 2008. Further reductions in contaminants will be achieved as owners and operators of wastewater systems that are subject to the Wastewater Systems Effluent Regulations (which entered into force June 2012) comply with the effluent quality standards indicative of secondary wastewater treatment. Internationally, the Government of Canada has been working with other countries under the Stockholm Convention on Persistent Organic Pollutants and the Minamata Convention on Mercury to minimize exposure to contaminants from foreign sources.

North Atlantic right whales are also exposed to naturally occurring toxins such as paralytic shellfish poisoning (PSP) toxins. In the Bay of Fundy PSP toxins have been found in North Atlantic right whale feces and could have sub-lethal health effects on individuals (Doucette et al. 2006).

6.3.2. Acoustic Disturbance

Acoustic disturbance is generally attributable to two types of anthropogenic noise: impulsive sounds such as seismic airgun operations and military sonar (noise with high peak sound pressure, short duration, fast-rise time, and broad-frequency content); and non-impulsive (i.e., steady-state) noise, such as that produced during shipping activities (NMFS 2016). Both seismic operations and shipping activities produce sounds that have been shown to interfere with normal activities and movements of cetaceans (Richardson et al. 1995).

There has been little progress in directly addressing anthropogenic noise threats to North Atlantic right whales in Canadian waters. The changes in vessel traffic due to recovery activities focused on reducing vessel strikes in the Bay of Fundy and Roseway Basin regions may have reduced noise in North Atlantic right whale critical habitat, but this has not been studied or quantified. Some passive acoustic monitoring studies that measure baseline noise levels within the distributional range of North Atlantic right whales are currently underway. DFO, JASCO Applied Sciences, and other organizations are collecting data and characterising the soundscape, including natural and ambient noise levels, throughout Nova Scotia, Newfoundland and Labrador, and the St. Lawrence estuary and Gulf of St. Lawrence waters. Some, but relatively limited monitoring of noise levels in and around identified critical habitats has occurred.

The recovery activities outlined in the Progress Report related to acoustic disturbance focus on reviews of environmental assessments of oil and gas exploration and seismic exploration programs (DFO 2016b). DFO completed a review of the mitigation and monitoring measures used for seismic airgun activities in and near the habitat of cetacean species at risk, identifying enhanced and additional mitigation measures that should be implemented for Species at Risk (DFO 2014b).

The Recovery Strategy identified shipping noise as a threat to North Atlantic right whales; however, it does not propose mitigation measures from this disturbance. Rolland et al. (2012) demonstrated that a 6 dB reduction in background noise (50Hz – 20 kHz) in the Bay of Fundy was associated with a reduction in the hormones associated with stress in North Atlantic right whales. Little effort has been made to monitor sound levels associated with shipping noise within North Atlantic right whale critical habitat even though the outbound lane of the Bay of Fundy TSS intersects the critical habitat (Figure 2). Not only are large vessels required to transit through the TSS, but transit at a higher speed compared to the inbound lane of the TSS (Vanderlaan et al. 2008) making the critical habitat for North Atlantic right whales a potentially noisy area. On Stellwagen Bank, an area also intersected by the Boston TSS, Hatch et al. (2012) estimated at 63-67% loss in North Atlantic right whale communication space due to vessel noise. Clark et al. (2009) postulated that North Atlantic right whales are particularly vulnerable to communication masking as a result of chronic noise from vessel traffic. Vessel noise could be increasing stress levels in North Atlantic right whales, masking their "contact calls", and decreasing their communication space. 

On Roseway Basin the majority of vessels transit around North Atlantic right whale critical habitat, as the critical habitat has the same boundaries as the IMO-adopted ATBA. However, non-compliant vessels still transit through the critical habitat possibly leading to acoustic and vessel-presence disturbance. Vessel noise can travel great distances and even vessels transiting near but not within Grand Manan and Roseway Basins can potentially impact the acoustic environment within these critical habitat areas. In the Recovery Strategy, acoustic disturbance has been identified as having the potential to result in destruction of North Atlantic right whale critical habitat (DFO 2014) and it is not known if the level of noise generated by vessels transiting in or near the TSS or ATBA could be considered destruction of North Atlantic right whale critical habitat.

One study monitored noise levels in the Bay of Fundy to compare among other North Atlantic right whale critical habitats (Parks et al. 2009). Parks et al. (2009) determined that the Bay of Fundy was the loudest of the three areas studied that also included Cape Cod Bay and the southern calving ground off the coast of Georgia. This research has not continued, therefore it is not possible to determine if noise has changed in the Bay of Fundy critical habitat. Further studies are required to monitor this threat and determine if noise is increasing, decreasing, or remaining constant. One option to monitor noise, both contemporary levels and historic levels, could be to use vessel presence and the number and type vessels as a proxy for noise levels, ensuring to explicitly state the caveats and assumptions associated with using these data. Vessel data are available to monitor the number and type of vessels in coastal areas, some starting as early as 2007, through DFO's Canadian Coast Guard terrestrial network of AIS receivers and the Taggart Lab (Dalhousie Oceanography) AIS network.

6.3.3. Vessel-presence disturbance

Vessel-presence disturbance has been identified as a threat in the Recovery Strategy; however, there is no performance indicator associated with vessel-presence disturbance (Appendix C, Table C3). The potential harmful effects of vessel-presence disturbance are unknown and this threat represents a large knowledge gap. Further research is needed to determine the effects on the health and survival of North Atlantic right whales attributable to vessel-presence disturbance to inform the design of effective threat-based recovery activities. As no measures are in place to reduce the unknown effects of this threat, effectiveness of the Recovery Strategy relating to vessel-presence disturbance cannot be evaluated.

6.3.4. Changes in Food Supply

North Atlantic right whale occupancy in critical habitats has been linked to food supply (Patrican & Kenney 2010; Davies et al. 2015a). Adequate food resources are directly connected to fitness of individuals and the viability of the North Atlantic right whale population (Schick et al. 2013; Rolland et al. 2016) and there is some evidence that nutritional stress may be limiting recovery (Greene and Pershing 2004; Fortune et al. 2013). Changes in food supply have been identified as a threat to North Atlantic right whales and prey removal from identified critical habitats has the potential to result in the destruction of critical habitat (DFO 2014). Changes in food supply that threaten North Atlantic right whales include decreases in food availability and condition (i.e., nutritional value) and shifts in distribution, especially shifts that move food supplies outside of critical habitats that offer some protection to North Atlantic right whales from other threats. Several studies are completed or underway to examine the factors affecting Calanus distribution (e.g., Michaud and Taggart 2007, 2011; Davies et al. 2015b; Albouy-Boyer et al. 2016). At this time, there is no fishery for Calanus and therefore no competition for this food resource other than other marine animals that also prey on copepods. As such, little is being done to address this threat other than research that examines the variation in distribution and abundance of Calanus.

As critical habitat for this species was originally defined as "areas that possess the environmental, oceanographic and bathymetric conditions that aggregate concentrations of right whale prey, especially stage-C5 Calanus finmarchicus copepodites, at interannually predictable locations" (Brown et al. 2009), activities around critical habitat are discussed here. Critical habitat has been defined in both Canada (DFO 2014) and the USA. USA recently identified the Gulf of Maine as critical habitat that includes the previously defined critical habitat in Cape Cod Bay and in the Great South Channel. The Southern calving ground was also expanded to include all coastal waters of Georgia, South Carolina, and part of North Carolina; increasing the identified critical habitat area by ~5-fold, from 1,611 nm2 to 8429 nm2 (NOAA 2016b). In the Recovery Strategy, the Roseway Basin critical habitat was identified as possibly requiring refinement of the geospatial boundaries pending further research and scientific review. Davies et al. (2014) proposed that the critical habitat should be expanded based on oceanographic and bathymetric conditions that support the aggregation of copepods at depth. Refinement of currently identified critical habitat, and identification of new critical habitat in areas being more frequently used by right whales, could provide further protection of North Atlantic right whales.