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

Threat-Based Recommendations

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

8. Threat-Based Recommendations

The following sections present recommendations about the most effective (and thus high priority) recovery activities to reduce threats to North Atlantic right whales and reduce risks to the population, based on this review that was made under a limited time frame and a limited review process. These recommendations should therefore be considered with these caveats in mind, noting that it is possible that with a more extensive scientific review process, different recovery activities might be recommended.

There is considerable evidence that vessel strikes and fishing-gear entanglements are the primary and immediate concerns for North Atlantic right whale recovery as they are the leading cause of documented human-induced deaths (van der Hoop et al. 2013), are known to cause serious injury and harm, and consequently have resulted in population-level impacts as the PBR has been exceeded every year except one between 1995 through 2009 (van der Hoop 2013) There is less evidence of direct impacts on North Atlantic right whale recovery from disturbance and habitat degradation threats, largely due to the difficulty in assessing the likely sub-lethal impacts from these threats on individuals and populations. The extent and severity that the negative effects of threats related to disturbance and habitat degradation have on health and long-term survival represent a knowledge gap for cetaceans in general.

In most cases, the most effective recovery activity would be to remove the threat from areas where North Atlantic right whales are present - i.e., spatiotemporal avoidance (Table 4). To accomplish this we need to know (1) where the North Atlantic right whales are in space and time; (2) where the threat is in space and time; and (3) areas, in space and time, where the two intersect. Much of the work to assess the risk of vessel strikes and fisheries interactions within identified North Atlantic right whale critical habitat in Canadian waters has been completed, and has demonstrated that removing these activities from the critical habitats will reduce the risk of lethal vessel strikes and fisheries interactions (Vanderlaan et al. 2008, Vanderlaan and Taggart 2009, Vanderlaan et al. 2011). Given that the identified critical habitat supports important life functions for North Atlantic right whales and represents areas where the majority of right-whale sightings in Canadian waters have occurred, little additional research is needed to support that implementing spatiotemporal-avoidance measures in these areas will reduce the risk to the population. Spatiotemporal-avoidance measures should also be considered for other North Atlantic right whale high-use areas (for example, potentially in the southern Gulf of St. Lawrence); however, further work is required to define these other areas. Considerable research is required to explain the variation in North Atlantic right whale movements and residency patterns, thus continued studies focusing on distribution and habitat use are a high priority to support implementation of effective spatiotemporal-avoidance measures.

The following sections provide a more detailed description of spatiotemporal-avoidance measures and other recovery activities that must be undertaken to reduce the threats of vessel strikes, fishing-gear entanglements, and disturbance and habitat destruction for North Atlantic right whales, as well as research and monitoring activities required for implementing the measures and assessing their effectiveness. Table 5 presents a summary of the recommended recovery activities, including anticipated effectiveness from implementing such measures towards reducing risk and the estimated timelines for conducting the scientific research required to support successful implementation of the measures.

8.1. Vessel Strikes

 Several successful recovery activities have been implemented to reduce the risk of vessel strikes to North Atlantic right whales in both Canada and the USA, and a significant decrease in number of observed deaths of North Atlantic right whales attributable to vessel strikes has been documented. However the risk of lethal vessel strikes to North Atlantic right whales has not been eradicated. This threat still exists and does cause mortalities and serious injuries. Further measures could be implemented in Canada to reduce the risk of lethal vessel strikes, especially in identified critical habitats as well as in new areas where aggregations of North Atlantic right whales are being observed (e.g., the Gulf of St. Lawrence).

Although the 2003 modification to the Bay of Fundy TSS has reduced the risk of lethal vessel strikes, the amended TSS still intersects North Atlantic right whale critical habitat and not only puts North Atlantic right whales at risk of lethal vessel strikes but also exposes them to acoustic and vessel-presence disturbance. This has the potential to destroy critical habitat (DFO 2014) which is prohibited under the SARA. The TSS could be amended to further remove vessel transits from the critical habitat, also reducing vessel-presence disturbances and potentially vessel noise levels in the critical habitat.

The Roseway Basin critical habitat has the same boundaries as the recommendatory ATBA that was implemented to reduce the risk of lethal vessel strikes. The ATBA is a voluntary measure and the compliance with this recovery activity must continue to ensure sustained effectiveness. Compliance appears to be decreasing in 2016 (Vanderlaan and Taggart, unpublished data), and this suggests that further outreach to mariners must be conducted to ensure awareness of the ATBA and the IMO recommendations.

Vessels should also be removed from other North Atlantic right whale high-use areas. These may include relatively newly described aggregation areas such as those observed off the coast of the Gaspé Peninsula in the Gulf of St. Lawrence. Again, reducing the number of vessels in North Atlantic right whale high-use areas also decreases potential vessel-presence and acoustic disturbances. This recovery activity would require further research to find and define other North Atlantic right whale high-use areas.

In addition to spatiotemporal-avoidance measures, speed restrictions in the vicinity of critical habitats, in areas between the two identified critical habitats, and high-use areas when whales are present would also reduce the risk of lethal vessel strikes. North Atlantic right whales are highly mobile and although they tend to aggregate in specific areas, individuals are constantly on the move. By implementing a speed restriction, if a vessel were to strike a whale the probability of killing the whale is decreased (Vanderlaan and Taggart, 2007). Speed restrictions could be implemented as SMAs, similar to the USA, or in response to real-time detections or observations during surveys.

8.2. Fishing-Gear Entanglements

Contrary to the observed relative success of reducing the threat of vessel strikes, the threat of fishing-gear entanglement continues to be an urgent concern for North Atlantic right whales. Thus far, Canada has had a reactionary approach to fishing-gear entanglements focusing on disentanglement effort performed by various non-government agencies. Few proposed recovery activities focus on entanglement prevention (e.g., spatiotemporal closures) and mitigation (e.g., decreased breaking strength in rope). Many knowledge gaps remain about fishing-gear entanglements, such as the mechanisms of entanglement, the level of threat associated with each type of line in fixed fishing gear (e.g., groundlines versus endlines), and the threat level associated with different fisheries. Nonetheless removing fishing activities from the Grand Manan and Roseway Basin critical habitats when the whales are present (i.e., spatiotemporal closures) would reduce the risk of lethal fishing-gear entanglements as demonstrated in previous studies (Vanderlaan et al. 2011; Brillant et al. 2017). These studies are based on historical fishing data and Vanderlaan et al. (2011) aggregated the fishing data across several years to capture the spatiotemporal variation in fixed fishing gear deployments. Fishing gear should also be removed from other high-use areas; however, this does require research to define the boundaries of these areas. Reducing the spatiotemporal co-occurrence of North Atlantic right whales and fishing gear would reduce the probability of a whale encountering gear and becoming entangled. This recovery activity would prevent entanglements from occurring thus there are no associated reductions in health due to increased drag on the whale or injuries as a result of an entanglement. Spatiotemporal-fishing closures also may have the added benefit of reducing other threats to the population such as acoustic disturbance and vessel-presence disturbance.

The USA Atlantic Large Whale Take Reduction Plan (ALWTRP) began in 1997 and NOAA and the USA fishing industry has implemented approximately 20 years of gear modifications implemented with little testing and little success in reducing fishing-gear entanglements. The failure of gear modifications as a recovery activity for North Atlantic right whales stems from the inability to effectively test proposed solutions prior to their deployment (Moore 2014). Knowlton et al. (2015) recently recommended decreasing the breaking strength of ropes to ≤ 7.56 kiloNewtons (≤ 1700 pound-force) to reduce the number of life-threatening entanglements. This modification could be developed and tested to determine the feasibility of using such rope in Canadian fisheries. Alternatively (or additionally), removing gear, specifically lines, from the water column would also decrease the threat of entanglements. Development and testing of ropeless gear, and its feasibility for use in a variety of Canadian fisheries, should also be considered. However, until gear modifications are developed, tested, and put into place, the immediate focus should be on keeping gear and whales separate in time and space (Moore 2014).

Disentanglement does not prevent entanglement, rather it is reactionary. Its effectiveness is limited due to challenges associated with disentangling North Atlantic right whales. Furthermore, even if disentangled, a whale could still suffer from long-term health effects from the entanglement. Despite these limitations, with such a small population where the death of two females each year can jeopardize recovery of the species (Fujiwara and Caswell 2001), every effort should be made to reduce the effects of fishing-gear entanglements on individual whales when they occur. Thus when North Atlantic right whales become entangled in fishing gear, disentanglement efforts should be a priority. Gear retrieval and protocols for storing and examining gear should also be a priority as this provides further insights into the types of gear and the identity of fisheries causing entanglements.

Gear marking and gear reporting, though not preventative recovery activities, should be implemented to increase the probability of identifying the source of the gear involved in entanglements (e.g., endlines versus groundlines and specific fishery). Gear reporting (including when, where, and how much gear is being set) should be a requirement for industry as detailed location data allow for more accurate risk estimation and the development of recovery activities. Locational data are generally spatially aggregated for these types of analyses and unique identifiers are not used (Vanderlaan et al. 2011, Brillant et al. 2017). Data should be standardised across all regions within DFO and for appropriate analyses specific latitudes and longitudes are required rather than low resolution reporting polygons. Detailed information on vessel location and speed was necessary to mitigate the threat of vessel strikes in North Atlantic right whale critical habitats and mitigation would not have been possible without these data. Similarly, detailed information on fishing activities are required to develop effective mitigation to reduce risk of entanglement to North Atlantic right whales.

8.3. Disturbance and Habitat Reduction or Degradation

There is a lack of information that exists about the threats from disturbance and habitat reduction or degradation. While the direct effects of these threats on individual North Atlantic right whale health and population dynamics are generally unknown, recovery activities could be implemented to reduce potential impact on individuals and the population.

As previously noted, moving vessel traffic and fishing activities outside identified critical habitat and high-use areas would decrease vessel-presence disturbance and acoustic disturbance. Reducing vessel speed could also potentially reduce the noise from container ship (McKenna et al. 2013) and would also decrease the probability of a lethal injury if a vessel were to hit a whale (Vanderlaan and Taggart 2007). If speed restrictions were to be implemented to reduce acoustic disturbances, they would have to be balanced with the potential effects of increased disturbance due to prolonged vessel presence. Until more is known about which threat, acoustic disturbance or vessel-presence disturbance, is more harmful to North Atlantic right whales, it is challenging to design effective recovery activities to address these disturbances through speed restrictions.

Threat-based measures for directly reducing the impacts of contaminants cannot be recommended at this time due to existing knowledge gaps; therefore, research and monitoring are required to address this threat.

Changes in food supply could also be affecting the health of North Atlantic right whales and their distribution. Several studies are assessing variability in Calanus aggregations, distribution, condition, and have been trying to identify areas outside the critical habitat that could support North Atlantic right whale feeding aggregations. However, no threat-based measures for changes to food supply can be implemented at this time.

8.4. Required Research and Monitoring

For all of the recovery activities described above, population monitoring is required to determine if the measures have been effective in reducing the targeted threat. Population monitoring studies assess abundance, survivorship, and health of the animals. It is a high priority for such population monitoring studies to continue.

As well, monitoring scarring rates and injured or dead animals (necropsies) provides further insights into the causes of health declines and/or increases in mortalities. Documentation of all incidents involving North Atlantic right whales (and other cetacean species) should continue in support of tracking threats and learning more about how incidents occur. Data on marine mammal incidents are currently scattered throughout different organizations making comprehensive analysis difficult – data collection of incidents should be standardized nationally and made available for analyses (DFO 2016c). Necropsies should be performed on dead North Atlantic right whales whenever safe for the necropsy team. Necropsies provide crucial information on threats and are the only method that has a high probability to make a specific determination of the cause of death (Campbell-Malone et al. 2008); including ruling out some causes. Necropsies also provide valuable statistics to scientists and agencies responsible for North Atlantic right whale protection and recovery. Data collected from North Atlantic right whale carcasses are the primary source of information on human-induced mortalities and is therefore essential for tracking causes of serious harm and mortality. Such data can also inform the development of future recovery activities. For example Vanderlaan and Taggart's (2007) study estimating the probability of a lethal injury to a large whale as a function of vessel speed at the time of collision was based on published reports documenting vessel strikes (e.g., Laist et al. 2001; Jensen and Silber 2003). This study was used, in part, to justify the 10 knot speed restriction in the USA and would not have been possible if necropsies were not done to determine the cause of death, and if the data were not amalgamated into a centralized database.

Managing human activities that threaten North Atlantic right whales requires knowledge of times and locations where the whales and the threats co-occur. Survey effort has generally focused on known seasonal aggregations of the North Atlantic right whales and only covers a fraction of their distribution (Brillant et al. 2015). Their movement patterns have implications for conservation patterns (Schick et al. 2009), especially as recovery activities, proposed and implemented, focus on critical habitats. Further research is required to detect, survey, and study North Atlantic right whales outside their traditional areas of occurrence. This research could identify high-use area and migratory pathways where further recovery activities should be implemented.

Rate of interactions in Canadian waters is a performance indicator for the threat of vessel strikes and fishing-gear entanglements in the Recovery Strategy. The data available for measuring fisheries interactions with large whales are frequently too limited to support strong, statistically-significant conclusions about the efficacy of recovery activities (Pace et al. 2014). This is often true in conservation biology and van der Hoop et al. (2014) attributed their inability to detect significant interactions in space and time following the implementation of speed restrictions in the USA, to low compliance; insufficient time and/or monitoring to examine effectiveness; or the SMAs being too short in duration and/or too small. A simulation study concluded that rates of detected mortalities attributable to fishing gear must be decreased by at least 50% to be able to detect a change within 10 years (Pace et al. 2014). Although the abatement of threat is listed as immediate in many of recovery activities proposed, it will take a much longer time period to be able to detect changes within the population. 

Monitoring and evaluating compliance are a crucial component of any conservation initiative (Stem et al. 2005). Monitoring allows for an accurate evaluation of the effectiveness of recovery activities, including determination of reasons (such as lack of compliance with mandatory and voluntary measures) why implemented recovery activities may be ineffective. For any recovery activity implemented, it is imperative that a monitoring plan is developed and implemented to determine compliance and effectiveness of the measure.