Review of the Effectiveness of Recovery Measures for St. Lawrence Estuary Beluga

Effectiveness of recovery measures and recommended changes or additions

Table of Contents

• Complete Text
• 1. Context/Background
• 2. Objective of this review
• 3. Sources of information
• 4. Methods for assessing effectiveness of recovery measures
• 5. Review of Recovery Measures
  • 5.1 Recovery Objectives
  • 5.2 Threats
  • 5.3 Review of Recovery Measures
• 6. Effectiveness of recovery measures and recommended changes or additions
  • 6.1 Overall Assessment of the Effectiveness of Recovery Measures
  • 6.2 Effectiveness of threat-based recovery measures, and recommended improvements
    • 6.2.1 Recovery measures associated with objective 1. Reduce contaminants in beluga, their prey, and their habitat
      • 6.2.1.1 Effectiveness of actions
      • 6.2.1.2 Focus of improvements to current recovery measures and additional measures
      • 6.2.1.3 Monitoring and research to support recommended recovery measures
    • 6.2.2 Recovery measures associated with objective 2. Reduce anthropogenic disturbances
      • 6.2.2.1 Effectiveness of actions
      • 6.2.2.2 Focus of improvements to current recovery measures and additional measures
      • 6.2.2.3 Monitoring and research to support recommended recovery measures
    • 6.2.3 Recovery measures associated with objective 3. Ensure adequate and accessible food supplies
      • 6.2.3.1 Effectiveness of actions
      • 6.2.3.2 Focus of improvements to current recovery measures and additional measures
      • 6.2.3.3 Monitoring and research to support recommended recovery measures
    • 6.2.4 Recovery measures associated with objective 4. Mitigate the effects of other threats to population recovery
      • 6.2.4.1 Effectiveness of actions
      • 6.2.4.2 Focus of improvements to current recovery measures and additional measures
      • 6.2.4.3 Monitoring and research to support recommended recovery measures
    • 6.2.5 Recovery measures associated with objective 5. Protect the beluga's habitat in its entire distribution range
      • 6.2.5.1 Effectiveness of actions
      • 6.2.5.2 Focus of improvements to current recovery measures and additional measures
      • 6.2.5.3 Monitoring and research to support recommended recovery measures
    • 6.2.6 Recovery objective 6. Ensure regular monitoring of the St. Lawrence Estuary beluga population
      • 6.2.6.1 Effectiveness of actions
      • 6.2.6.2 Focus of improvements to current and additional monitoring measures
• 7. Conclusions
• 8. Acknowledgements
• 9. Literature Cited
• Appendix 1

6. Effectiveness of recovery measures and recommended changes or additions

In the following sections, the recovery measures that have been implemented to reduce each of the identified threats are described in general terms, along with any information available on population demography or health to illustrate the effectiveness of the measures. As it is difficult to assess the effectiveness of individual recovery measures and their associated impacts on the population, all recovery measures aimed at reducing a specific threat are considered collectively to evaluate whether they have been effective at reducing the threat.

The recovery measures listed under objective 6 in the Recovery Strategy do not directly reduce threats to SLE beluga. However, monitoring programs that fall under this objective are important for informing threat-based mitigation measures. The effectiveness of recovery measures implemented to more directly reduce or mitigate threats often relies on information obtained under these non-threat-based measures. Additionally, knowledge gained through completing measures under Objective 6 can be used to inform the development of new recovery measures to reduce the impacts of threats. As this objective is not threat-based, nor directly related to recovery, a measure of their effectiveness is not possible; however, their importance for assessing recovery and the effectiveness of other recovery measures is further discussed in the following sections.

6.1 Overall Assessment of the Effectiveness of Recovery Measures

The decline (1% per year) in the SLE beluga population size documented over the past 15 years after a period of relative stability (Mosnier et al. 2015), and the apparent absence of expansion in beluga distribution (Mosnier et al. 2010; Gosselin et al. in press), indicate that recovery objectives for population size and distribution range have not been achieved. They also indicate that, while recovery actions completed had allowed the population to stabilize prior to 2000, they did not permit the population to grow at the targeted 2% growth rate and they have since been insufficient for this population to cease decreasing.

A recent population viability analysis (PVA), which assumed a warming climate and various levels of what are now considered to be the three main threats to the population (i.e., noise/disturbance, persistent organochlorine contaminants, and reduced availability of prey), was recently performed for SLE beluga (Williams et al. in press). It was concluded that the SLE beluga population was unlikely to reach the recovery goal of 7,070 individuals by 2100, even under the most optimistic management scenarios of these threats. While uncertainty exists as to the relative importance of the three threats that were considered in the model in terms of preventing recovery, the strong negative anomalies observed since 2010 in sea ice extent and duration and water temperatures, if they persist, come out as factors potentially reducing the ability of the SLE beluga (or resilience) to cope with the other three threats (Williams et al. in press).

Given the above information, it is evident that collectively, the recovery measures laid out in the Recovery Strategy that have been completed to date, have not led to the achievement of recovery objectives, and current population trend is also not indicative of progress towards recovery. The following section will assess progress towards abating threats preventing beluga recovery.

6.2 Effectiveness of threat-based recovery measures, and recommended improvements

6.2.1 Recovery measures associated with objective 1. Reduce contaminants in beluga, their prey, and their habitat

Recovery measures that fall under the first recovery objective aim to reduce the threat of contaminants. SLE beluga are exposed to a variety of toxic chemical compounds mainly through their diet, but also through their environment (sediments, water, air). Some pollutants have existed for a long time in the beluga environment, and have been regulated well before concerns were raised about their potential effects on beluga health (e.g., PCBs, DDTs, PAH). Other toxic chemical compounds were introduced in the environment more recently (e.g., polybrominated dichloroethane or PBDEs) and have been regulated after 2005 (i.e., after SARA listing) but not necessarily as a result of recovery measures in the beluga Recovery Strategy. Others (e.g., other flame retardants) are emergent and remain unregulated.

The monitoring of levels of persistent organochlorine compounds (e.g., DDTs, PCBs, Mirex, dioxins, furans) and some metals (e.g., mercury) in SLE beluga and studies of their potential effects were initiated in the early 1980s, i.e., prior to the SARA listing of the population (e.g., Martineau et al. 1987; Muir et al. 1996a; 1996b; DFO 2012 for review). These studies have shown that SLE beluga are among the most contaminated marine populations on the planet, which raised concerns for their health. There were also concerns about a class of contaminants (polyaromatic hydrocarbons or PAH) originating from aluminum smelters that were detected in SLE beluga; PAH were thought to be responsible for the high rates of cancers documented in the population (Martineau et al. 2002).

A number of recovery measures have been proposed which aimed primarily at enhancing efforts to reduce contaminant levels in beluga, their prey and habitat, and at understanding their pathways of effects (Table 2). Research on the physiological effects of contaminants on SLE beluga has been limited since SARA listing. The studies advancing our understanding of health effects of contaminants have come primarily from other Arctic populations of beluga and other marine mammal species.

Regulatory actions to reduce toxic chemical compound discharges have been put in place for a number of compounds after 2005, although regulations were already in place for several chemical compounds before that time (Table 2). Contaminated terrestrial and aquatic sites have been identified and prioritized for decontamination long before SARA listing (in 1998), and decontamination initiatives have been put forward at various sites in the Great Lake region since then (see Table 2).

6.2.1.1 Effectiveness of actions

Given that beluga are exposed to a variety of pollutants that have different histories in terms of introduction date, abundance and persistence in the environment, as well as regulatory actions, it is challenging to assess whether the threat from contaminants as a whole, has decreased for beluga.

Beluga are long-lived and several contaminants are persistent and volatile. As a result, expectations were that it would take several years for changes in contaminants in beluga prey or the environment to cascade into significant changes in beluga contaminant burdens and health. . Overall, there are signs that actions undertaken over the past several decades have improved the quality of SLE beluga habitat and prey for some contaminants. These improvements have had cascading effects into beluga. Concentrations of several persistent organochlorine compounds that are now regulated, such as dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyl (PCBs), or mirex remain high in SLE beluga, but they have stopped increasing. Some of these compounds have started to show declining trends, especially in reproductive females, who can offload some of their contaminant burden to their newborn calf (Gouteux et al. 2003; Lebeuf et al. 2007; 2012; 2014).

Conversely, highly toxic flame retardants such as the polybrominated diphenylether (PBDEs), for which regulations have been implemented only recently, increased exponentially in beluga tissues during the 1990s. Since then, levels either stabilized or continued increasing but at a slower rate (Lebeuf et al. 2014; Simond et al. in press). Other, emerging and currently unregulated contaminants remain unquantified in beluga tissues given the currently limited research efforts steered toward contaminants and SLE beluga (but see Simond et al. in press).

There is some indication that for some classes of contaminants, the recovery measures completed to date have had positive effects on beluga habitat, with cascading effects on beluga health. A notable example is the apparent decrease in the incidence of cancer in beluga born after the abrupt decline of PAH concentrations in surface sediments of their summer area (Lair et al. 2016). It is also possible that the decrease in cancer is linked to PCB reductions, which indirectly acts on levels of PAH by altering their degradation into carcinogenic metabolites (Lair et al. 2016). It is not possible to determine the specific contribution of the various management actions undertaken (e.g., regulations for certain contaminants vs cleaning of contaminated sites) to the overall improvement in beluga health and contamination.

These results are encouraging and indicate that actions that have been undertaken in the Great Lakes or other sectors upstream of, or within the SLE beluga habitat have been effective to some extent in reducing the overall input of contaminants in the beluga environment over a time scale of a few decades. However, levels of regulated contaminants continue to be high in beluga even if some have stabilized or declined in their tissue. Others such as PBDEs continue to increase, indicating that current actions are not sufficient to abate this threat.

6.2.1.2 Focus of improvements to current recovery measures and additional measures

PBDEs and other highly toxic flame retardants are currently of great concern as they are suspected to be playing a role in the lack of beluga recovery, and the worsening of their situation. Since 2008, an abnormally high number of beluga newborn calves were found dead in the SLE (Lesage et al. 2014b), a trend which has been accompanied since 2010 by a new phenomenon of regular reports of peripartum complications among dead adult females (Lair et al. 2016). Interference of PBDEs with normal thyroid activity has the potential to induce such effects, or to make neonates less fit to survive (Lair et al. 2016).

In light of the achievements of recovery measures that have been completed, and of these recent findings, recovery measures to reduce threat from contaminants should aim primarily at continuing to reduce toxic chemical compound discharges and transport to beluga habitat. Measures need to include additional regulations, full application or expansion of existing regulations (see Table 2 for specific regulations), adequate enforcement, as well as decontamination of aquatic and terrestrial sites (Table 3). PBDEs and emergent flame retardants need to receive particular attention given their high toxicity, and possible role in the current increase in mortality of adult females and calves. It is important to note that improvements resulting from the implementation of any measure aimed at reducing the threat of contaminants will only become evident over the longer-term (i.e.: >10 years) due to the nature of the threat.

6.2.1.3 Monitoring and research to support recommended recovery measures

Given the wide and changing variety of toxic chemical compounds in the environment, there is a need to review the information available on contaminant loads in beluga, toxicity thresholds and expected health effects in order to ensure regulatory actions are steered toward the top priority toxic chemical compounds.

Time series exist for the incidence of cancer, peripartum problems, and for levels of several toxic organochlorine compounds in beluga; time series may exist for sentinel species and habitat, but this could not be determined within the timeframe that this review was completed. Existing time series have proved to be useful indicators of effectiveness of actions taken to reduce beluga exposure to toxic chemical compounds. As such, monitoring of these aspects needs to be maintained. Time series should also be built to monitor levels and trends of emergent flame retardants and other toxic chemical compounds in beluga and their habitat, to help assess the effectiveness of the recommended recovery measures addressing those contaminants (e.g. regulations). Such a time series can inform the adaptation or refocusing of management measures as needed over time.

6.2.2 Recovery measures associated with objective 2. Reduce anthropogenic disturbances

Recovery measures that fall under the second recovery objective aim to reduce the threat of anthropogenic disturbances. A variety of anthropogenic activities can interfere with the normal activities of SLE beluga either by masking important acoustic signals, or by inducing behavioural or stress responses (Clark 2009). These activities mainly include: shipping, ferry operations, whale-watching, recreational boating (either motorized or non-motorized), research activities and marine development projects. While shipping has existed in the SLE for over a century, whale-watching and other activities are more recent. Similarly, time series to evaluate trends in these activities are limited to only one or two decades, and to only a few years in the case of their impacts (e.g., noise levels) (see Appendix 1).

The mitigation of effects from disturbance and noise is a relatively new phenomenon, with the first studies being conducted in the Arctic in the 1970s. Therefore, very few actions were undertaken to mitigate this threat prior to posting of the first SLE beluga recovery plan in 1995, and several others were implemented after SARA listing 2005. Some of these measures aimed at better defining levels where significant effects might occur, while others intended to reduce physical disturbance of beluga, or noise levels in their habitat (Table 2).

6.2.2.1 Effectiveness of actions

The research conducted under the auspices of the Recovery Strategy led to a better understanding of the vessel fleet characteristics and composition, and of the vessels that are most likely to interfere with the SLE beluga's normal behaviour. This potential for interference exists, either because of vessel noise output (e.g., container ships), the amount of transits they represent (e.g., ferries), their location (overlap with important habitats for females and calves), or their acoustic overlap with beluga echolocation or communication frequency bands (e.g., whale-watching vessels) (McQuinn et al. 2011; Gervaise et al. 2012; Simard et al. 2014; 2016). Impact studies indicate that merchant ship traffic exposes a substantial proportion of the SLE beluga population to noise levels likely to induce negative responses many times a day, the vast majority of exposed animals being females with calves or juveniles (Lesage et al. 2014b). Studies also indicate that ferries and other large ships can reduce the acoustic habitat of beluga to a fraction of what it is expected to be under natural conditions (Gervaise et al. 2012), and that the noisiest areas are located along the north shore and at the mouth of the Saguenay River, with the quietest areas being found along the south shore and in the Upper Estuary (McQuinn et al. 2011; Lesage et al. 2014a; Roy and Simard 2016).

Several of the recovery measures implemented have likely raised awareness about the conservation status of SLE beluga, or have contributed to limiting disturbance or noise output in beluga habitat. However, there is no indicator available to assess changes since the species was listed in underwater noise levels, beluga exposure to noise, compliance with regulations, or the extent to which development projects where noise mitigation measures were to be implemented effectively complied with these requirements. Therefore, the effectiveness of recovery measures aimed at reducing the noise aspects of the disturbance threat cannot be assessed in quantitative terms here.

A review of the evolution of marine traffic and interactions with SLE beluga indicates that more can be done to reduce beluga exposure to whale-watching activities, which contribute both to the noise and physical disturbance aspects of the threat. Beluga are targeted by a small percentage of the whale-watching activities in the Lower SLE, but this percentage might have slightly increased over recent years. In the Upper SLE, an area used almost exclusively by females and calves and juveniles, whale-watching operations are limited, but are focused largely or exclusively on beluga (Ménard et al. 2014; Martins 2016).

Overall, there is currently no indication that interactions of beluga with vessels or the amount of traffic (merchant, recreational, whale-watching) in their habitat, a proxy for underwater noise levels and level of disturbance have decreased since SARA-listing in 2005. Therefore, we consider the recovery measures implemented to date to have been collectively ineffective at reducing the threat from underwater noise and physical disturbance.

6.2.2.2. Focus of improvements to current recovery measures and additional measures

Unusually high numbers of dead beluga calves were reported in 2010 and 2012 (Lesage et al. 2014b). These anomalies coincided with peaks in recreational boating activities at the Tadoussac marina, higher-than-usual co-occurrences between beluga and boats in the Saguenay Fjord, and good weather conditions during July and August in the critical habitat of SLE beluga (Ménard et al. 2014). These results have raised concerns about a potential link between anthropogenic disturbance during the calving period, and increased calf and female peripartum mortalities reported in those years.

Under the new Quebec Maritime Strategy, and other recent or proposed economic development initiatives within and outside the SLE beluga's habitat, it is expected that the number of merchant ship transits through the beluga habitat will increase. These new activities may add traffic in areas located outside the main shipping lane, and that are currently relatively quiet and only lightly exposed to marine traffic. This increased activity is of concern as it might result in an overall decrease in the quantity of quiet habitat available to beluga.

There are several recovery measures that could be undertaken relatively rapidly that would result in immediate reductions of beluga exposure to noise and interactions with vessels, and would help mitigate impacts from future developments. Identifying and protecting areas of the SLE that are both currently relatively quiet and important for SLE beluga could result in the creation of acoustic refuges or 'opportunity sites', allowing important conservation gains to be made for the future, at little societal costs (Williams et al. 2015). Within the limits of the SSLMP, a review of the zoning plan to implement exclusion zones could enhance protection of important habitats from noise and physical disturbance. Examining the placement of shipping routes relative to important beluga habitat can also be done in the short-term and might reveal areas where minor adjustments can be made that result in significant gains in terms of acoustic quality of the habitat or reduction in beluga exposure to noise. Replacing noisy highly-used ferries such as the Baie Sainte-Catherine/Tadoussac ferry by road infrastructure or quieting down ferries could considerably reduce noise levels in an important habitat of beluga.

Actions also need to be undertaken to increase awareness and compliance of users with regulatory and voluntary measures. Research-based actions leading to a better characterization of the fleet (both merchant ships and whale-watching vessels) would help steer efforts toward the most problematic vessels.

Currently, new development projects, including their associated vessel traffic, are assessed on a case-by-case basis for their impacts, without consideration of impacts they might generate outside the immediate vicinity of project location, or of impacts from other projects or activities allowed in the same region. A strategic (or programmatic) review of all activities and development projects contributing to noise and vessel traffic in the SLE is greatly needed, as it will provide a framework to set management objectives (e.g., in terms of noise levels or amount of traffic not to exceed), improve spatial planning, and assess and manage cumulative or aggregated effects of economic activities on the beluga and its habitat (Wright and Kyhn 2014).

6.2.2.3 Monitoring and research to support recommended recovery measures

No indicator of effectiveness exists for any of the past recovery measures dealing with this threat. Indicators should be developed in priority to assess the evolution of noise levels and traffic in key habitats for beluga, as well as the degree of interactions between SLE users and beluga. Research that helps better understanding how chronic sources of noise negatively impact beluga health and behaviour could help better target recovery actions and inform management objectives for noise and traffic levels.

6.2.3 Recovery measures associated with objective 3. Ensure adequate and accessible food supplies

Recovery measures that fall under the third recovery objective aim to reduce the threat of inadequate and inaccessible food supplies. The effectiveness of recovery measures addressing this threat ultimately depends on the ability to identify the key prey species of SLE beluga. While an extensive diet study was conducted in the 1930s (Vladykov 1946), this information remains of limited use to assess current diet given it was mostly acquired from a site that is no longer used by SLE beluga today. Contemporary diet information is limited given that beluga found dead of illness often have empty guts. However, some insights into beluga spring and summer diet have been gained from continued sampling efforts of beluga guts, as well as through indirect methods using various chemical tracers such as stable isotopes, fatty acids and contaminants (Nozères 2006; Lesage 2014; Lesage et al. 2017). While data indicate a diverse diet, they also suggest that the bulk of the beluga diet is formed of only a handful of prey species, and that the species targeted varies by month, location and season. Groundfish such as cod species, redfish, white hake, and several forage species such as capelin, herring and sandlance, along with tomcod and rainbow smelt are probably important for SLE beluga. As a result, actions directly or indirectly protecting or increasing the abundance of these species are likely to be beneficial to SLE beluga.

Recent studies also highlighted a link between a decline in sea ice cover and water temperature and a decrease in beluga calf survival (Williams et al. in press). These warming conditions may have affected beluga directly, but more likely, indirectly by affecting prey distribution and biomass and thus, their availability to adult females (e.g. Buren et al. 2014).

The management and monitoring of fish and invertebrate populations that may constitute potential prey of beluga is conducted by DFO and has been implemented well before posting of the recovery plan (1995) or Recovery Strategy (2005), with an implementation date varying among species. Currently, there is little effort to specifically monitor marine fish and invertebrate stocks in the SLE simply because of the low levels of fishery. Exceptions exist for some anadromous and diadromous species such as the American eel, tomcod and rainbow smelt.

Recovery measures proposed in the Recovery Strategy were meant to enhance protection of prey spawning and rearing sites and limit removals by fisheries or other activities likely to affect prey or their habitat (Table 2).

6.2.3.1 Effectiveness of actions

Scientific studies indicate that some of the prey available to beluga are produced locally while some are imported from the Gulf of St. Lawrence. Therefore, in order to be effective, recovery measures need to target prey in the two regions. Recovery measures that were put in place to limit commercial fisheries or protect fish or their habitat in the SLE have likely been beneficial to beluga, although there is no direct quantitative indicator of the effectiveness of these measures for improving prey availability to beluga. In the Gulf of St. Lawrence, the absence of fishing for some forage species helped mitigate the threat of inadequate food supplies to some extent, since it prevented fisheries for some forage species that the beluga either prey upon (e.g., sandlance), or that the beluga's prey depend on (e.g., krill and copepods). In 2009, a new policy `New Fisheries for Forage Species` was introduced. The policy allows a forage fish fishery in cases where all the conservation objectives prescribed by the directive are met. However, no new fishery of this type has been proposed or undertaken since SARA-listing or since the 2009 directive was implemented.

Groundfish stocks in the Gulf of St. Lawrence collapsed in the early 1990s and some of these species represent beluga prey (e.g., cod, redfish). These once abundant resources were never replaced by pelagic fish or other species, leaving the ecosystem in an overall biomass deficit (Plourde et al. 2014). A moratorium on the Atlantic cod fishery has been implemented in the SLE and southern Gulf of St. Lawrence since 2009 to allow population recovery, and remains in place today. However, stock size remains at a small fraction of levels that prevailed in the 1970s or 1980s. Globally, several of the groundfish stocks, and forage species that might be particularly important for beluga (e.g., 4T spring herring) remain at low levels. Therefore, we conclude that recovery measures implemented since SARA-listing have been ineffective at increasing beluga access to adequate prey biomasses. In fact, little has been done to address this threat, which up until recently, was only considered a potential threat.

6.2.3.2 Focus of improvements to current recovery measures and additional measures

The decline of the beluga population in the late 1990s and changes in population dynamics coincided with changes in several environmental conditions, including a decline in the abundance of demersal fish and some pelagic prey (Plourde et al. 2014), suggesting that food supply may have become limited and may still be playing a role in the current decline. A population viability analysis indicated that management actions leading to an improvement in demersal fish and 4T spring herring availability would have beneficial effects on the SLE beluga population growth rate (Williams et al. in press). Therefore, recovery measures acting on the levels of current and new fisheries, or protecting the habitat of beluga prey, including their food supply (forage fish and invertebrates), could help increase prey availability to beluga (Table 5). For instance, there is currently a fishery for 4T spring herring, a prey that might be particularly important for SLE beluga in the spring, and whose stock has collapsed around the year 2000 (Plourde et al. 2014). This stock is currently in the critical zone of the DFO Precautionary Approach and while reduction in commercial catches were applied since 2000, poor recruitment has constrained the rebuilding of this stock. Further reduction of harvest levels on herring (targeting mainly the spring component) could help the rebuilding of this key forage species to a healthy status, which would benefit beluga.

6.2.3.3 Monitoring and research to support recommended recovery measures

Our understanding of the beluga diet is still highly imperfect. Studies underway and using chemical tracers and gut contents need to be completed to ensure that recovery measures are focused on the most important prey species. These studies could be complemented by field studies of beluga feeding strategy and habitat use in order to gain insights into diet via habitat functions and characteristics. Approaches using bio-energetic models could help estimate beluga energy requirements and food supplies needed to support the population and allow recovery.

In parallel, there is a need to develop trend indicators that are specific to forage species and other beluga prey. Given the potential role of the receding sea ice cover, and of warming temperatures in explaining changes in prey distribution, biomass, or quality, monitoring programs for these physical aspects of the beluga environment need to be maintained to provide the context for interpreting changes in population dynamics of SLE beluga or other biological components of their ecosystem.

6.2.4 Recovery measures associated with objective 4. Mitigate the effects of other threats to population recovery

Recovery measures that fall under the fourth recovery objective aim to reduce the effects of other threats to population recovery. Among these other threats, collisions with small vessels (non-merchant ships) and entanglement in fishing gear have been responsible for a small number of deaths. Out of a sample size of 222 documented beluga deaths, 8 (4%) and 2 (1%) deaths were attributed to collisions and entanglement, respectively (Lair et al. 2016). Collision risk increases with speed and manoeuvrability, therefore the risk is relatively higher for smaller vessels than larger ones. Risk of entanglement is likely associated with gillnets in the SLE, although the type of gear involved in the documented deaths was not confirmed (Lair et al. 2016). Fisheries in the SLE currently operate at very low levels and therefore, incidents involving bycatch or entanglements of beluga have been rare in recent times.

Beluga also face a number of sporadic anthropogenic threats, which have the potential to cause multiple deaths in a short time, including spills of toxic substances, harmful algal blooms, and epizootic diseases (an epidemic in an animal population). As in many other temperate coastal areas, blooms of the harmful dinoflagellate Alexandrium tamarense occur on a regular basis in the SLE, with three major red tides documented in the past two decades (Scarratt et al. 2014). This algae has been associated with mortality of SLE beluga and other marine species in 2008 (Scarratt et al. 2014). Eutrophication (an increase in nutrients that promotes the growth of plants that take up oxygen and cause death of fish or mollusks), climatic variability, and changes in rainfall patterns may increase the frequency and severity of these events (Van Dolah 2000; Anderson et al. 2012). Given its small size, the SLE beluga population could be significantly affected by a single intoxication event (Scarratt et al. 2014).

There have been very few major toxic spills in the St. Lawrence, and so far, most have occurred in ports (Villeneuve and Quilliam 1999). However, the occurrence of strong tides and currents, seasonal ice cover, and frequent fog in the SLE and Gulf of St. Lawrence do increase the risk of toxic spills. The St. Lawrence River and Gulf of St. Lawrence has been identified among the zones where the probability of a large spill occurring is the highest (WSP Canada Inc. 2014). Because the area occupied by SLE beluga is limited, a large toxic spill could affect a significant number of individuals simultaneously and have long-term consequences for a large proportion of their range (Peterson et al. 2003).

Epizootic diseases have not been documented in SLE beluga. However, viruses such as papillomavirus and herpesvirus, which are the primary cause for these epidemic events, have been reported in SLE beluga (De Guise et al. 1994; Lair et al. 2014). Other pathogens such as the cetacean distemper virus or cetacean morbillivirus (CeMV) pose a high risk to SLE beluga because the population apparently has not been previously exposed to either of these pathogens (Mikaelian et al. 1999; Nielsen et al. 2000). Beluga could become exposed via range expansion of exotic infected marine mammal species as a result of climate change, or via biological contamination from municipal sewage, waste and ballast waters, and coastal runoff discharged into the St. Lawrence ecosystem. The small size of the beluga population, their gregariousness, potentially weakened immune system from chronic exposure to contaminants, and low genetic diversity make the SLE beluga population vulnerable to epizootic diseases.

6.2.4.1 Effectiveness of actions

A time series of nearly 30 years was needed to qualify the level of threat that collision risk and entanglement represent for SLE beluga (Lair et al. 2016). As a result, recovery measures were only recently put in place to reduce collision risks for SLE beluga, which represents about one individual every 4-5 years. These measures were meant to reduce the unpredictability of vessel movement to the beluga, by reducing their speed and avoiding abrupt changes in direction. While these measures have most likely been beneficial, the time series to document changes in this risk is currently too short to directly evaluate the effectiveness of this measure at reducing collision risk.

There have been very few recovery measures undertaken to address threats from toxic algal blooms, epizootic diseases, toxic spills, and fishing gear entanglement, presumably because of their relatively lower likelihood of occurrence when compared to the other threats identified for the population. However, the harmful algal bloom of 2008 indicates that when they occur, these events can remove several individuals from a population.

DFO has implemented systematic reviews of marine development projects on an individual basis since beluga Critical Habitat identification to assess impacts on beluga and their habitat, and incorporate mitigation measures when necessary. This increased scrutiny of individual projects has likely contributed to limiting habitat degradation. It must be noted that this measure did not aim at improving beluga habitat, but at limiting further degradation although again here, there is no quantitative measure of the effectiveness of this measure.

Data is currently too sparse to evaluate trends in harmful algal blooms, toxic spills, entanglements or collisions since SARA-listing. Therefore, the effectiveness of the recovery measures being implemented to address these threats remains difficult to assess.

6.2.4.2 Focus of improvements to current recovery measures and additional measures

The number of tankers travelling through the St. Lawrence transporting petroleum products and other toxic substances began to increase in 2014 with oil from Alberta being offloaded in Sorel, QC from the railway system using existing facilities, and is expected to continue to increase in the near- and medium-term future (COSEWIC 2014). As a result, risk of an accidental spill has also likely increased. There is an emergency plan for the SLE in case of an accidental toxic spill, but there are no guidelines dealing specifically with beluga (Government of Canada 2015) (Table 6).

Speed limits and codes of practice when in the presence of beluga have been put in place, but need to be better advertised. Promoting these measures with tour boat operators or pleasure craft owners through enforcement of regulations and awareness campaigns would contribute to reducing collision risk, also in addition to reducing disturbance and stress.

There is little that can be done to prevent epizootic disease outbreaks, once they have started. Reintroducing into the wild rehabilitated marine mammals that might have been in contact with pathogens can trigger such events. There is a need to formalize a directive regarding how to deal with ill marine mammals and their rehabilitation and relocation to ensure that the SLE beluga population benefits from as many individuals as possible, while minimising the risk of epizootic diseases.

Actions aiming at reducing anthropogenic inputs of nitrogen into the marine environment may help lower the likelihood of harmful algal bloom events.

6.2.4.3 Monitoring and research to support recommended recovery measures

The SLE beluga carcass monitoring program and systematic necropsies have allowed the monitoring of incidents (e.g., collisions, entanglement, intoxication), and the assessment of the relative impact of these threats on SLE beluga. The program also provides the opportunity to detect epizootic disease outbreaks. These examples demonstrate the value in maintaining the carcass monitoring program, but there remains a need for instating indicators to directly monitor trends in threat levels over time. Since 2012, the Automatic Identification System (AIS) system which is mandatory for vessels over a certain tonnage could be used to build a time series for threats from larger vessels; however, there is no similar technology available to systematically monitor traffic for smaller vessels, including the small whale-watching vessels and tour boats operating in the SLE. A monitoring program exists in the Lower SLE for harmful algal blooms, although the current situation does no longer ensure timely analysis of the collected samples. There is a need to fully reinstate the harmful algal bloom monitoring program in the SLE and to include urea among the nutrients that are monitored in the Lower SLE, as well as expanding these two monitoring programs to the Upper SLE. These programs, assuming support for timely analyses of collected samples is also provided, would allow the evaluation of trends in eutrophication, and the early detection of harmful algal bloom events, with the recognition that avoiding effects on beluga might be highly challenging. These programs are especially needed to gauge the relative importance of threats in the future, considering the potential for increase in frequency of these events due to climate change, and their value for understanding the environmental conditions favorable to such events and potentially predicting them.

Techniques currently available to recover oil in cold and ice-covered waters are known to be inefficient. Given that such environmental conditions prevail in the St. Lawrence for more than half of the year, there is an urgent need for new research to be conducted to identify ways to deal with accidental oil spills under these environmental conditions.

Indicators for compliance with regulations within the SSLMP, or with voluntary measures to reduce collision risks are also needed.

6.2.5 Recovery measures associated with objective 5. Protect the beluga's habitat in its entire distribution range

Recovery measures that fall under the fifth recovery objective do not aim to abate any one specific threat, but rather aim to fill data gaps regarding beluga distribution and high-use areas, including the functions they provide, and list broad protection measures for SLE beluga over their entire habitat.

6.2.5.1 Effectiveness of actions

Since SARA-listing, time series of aerial surveys and beluga herd tracking data have been extended and compiled to identify important habitat within the summer distribution range of SLE beluga (Lemieux-Lefebvre et al. 2012; Mosnier et al. 2016). This information was incorporated in a literature review, and largely formed the basis for identifying beluga Critical Habitat for the period from June to October (DFO 2012). Outside of this period, data remains relatively scarce (see Mosnier et al. 2010 for a review) although it suggests some beluga move to the Gulf of St. Lawrence during the fall and winter, with some remaining in the SLE.

The Government announced its intention to protect the beluga Critical Habitat in Canada Gazette I in May 2016 (http://www.gazette.gc.ca/rp-pr/p1/2016/2016-05-14/pdf/g1-15020.pdf). Once protected, any activity or undertaking likely to destroy any part of Critical Habitat will be deemed illegal. DFO currently operates under the spirit of this future protection, by systematically scrutinising marine development projects or activities on an individual basis that are likely to destroy beluga Critical Habitat, and by requiring mitigation measures when deemed appropriate. This procedure has improved the protection of SLE beluga habitat, although there is no direct indicator of effectiveness.

Currently, functions and key features of important areas of habitat within the Critical Habitat, and inter-connectivity among them, remain generally unknown, which limits our understanding of their relative importance for the recovery of the population. This knowledge is key for assessing potential impacts of marine development projects that are proposed in various parts of the beluga habitat.

Awareness campaigns and tour boat operation permit conditions that limit access to sensitive areas (e.g., limited access of tour boats to Baie Ste-Marguerite) have also likely contributed to the protection of beluga habitat, although again, direct indicators of the effectiveness of these measures do not exist.

Overall, scientific research was conducted since SARA-listing that contributed to filling data gaps and enabled Critical Habitat identification during part of the year. This identification has triggered an increased screening and mitigation of development projects and their impacts and thus contributed to increased protection of beluga habitat, which may have indirectly prevented increases in certain threats, such as underwater noise and physical disturbance. Other protective measures, including identification of Critical Habitat for the period of November through May, are pending.

6.2.5.2 Focus of improvements to current recovery measures and additional measures

The creation of a marine protected area (MPA) in the SLE, where certain restrictions similar to those enacted in the SSLMP could be in effect (e.g., limited access to sensitive areas), would help extend protection of beluga habitat to areas located along the south shore that are important to females and calves. Enacting of the zoning regulations in the SSLMP would further enhance protection of habitat, acknowledging that adequate enforcement is needed for those to be effective (Table 7).

Currently, the Critical Habitat identified covers only areas used between June and October given that data is insufficient outside of the summer period to identify important habitats. Critical Habitat identification should be extended as needed to include habitats used at other times of the year.

6.2.5.3 Monitoring and research to support recommended recovery measures

There is a need to identify high-use areas for the spring, fall and winter periods in order to extend Critical Habitat as needed and enhance protection via the Species at Risk Act. There is also a need to have a better understanding of the social structuring of the beluga population, and of the inter-connectivity among high-use areas, which currently impairs our capacity to fully assess potential impacts of development projects. Data exist to address these questions; it should be analyzed and results made available.

6.2.6 Recovery objective 6. Ensure regular monitoring of the St. Lawrence Estuary beluga population

Since SLE beluga were first assessed as Endangered by COSEWIC in 1983, several programs have been implemented to monitor different aspects of the population. These include a beluga carcass monitoring program (begun in 1982 and fully implemented starting in 1983), which comprises of full necropsies of carcasses that are relatively well preserved. This program has been maintained since 1983.

Monitoring of population size and distribution, as well as recruitment rate, using a standardized method (photographic aerial surveys) has also continued over time. However, these surveys were conducted on a more irregular basis after 2000, reducing our capacity to detect population trends thereafter. Another monitoring time series (based on visual aerial surveys) was initiated in 2001, which offers a parallel, although not comparable, index estimate of population trends. However, visual surveys do not allow detection of calves and so, cannot provide an index of recruitment.

A photo-identification study, conducted by the Group of Research and Education on Marine Mammals (GREMM) has been ongoing since the late 1980s. This program has the potential to contribute to documenting and explaining changes in recruitment rate, habitat use and other ecological questions.

6.2.6.1 Effectiveness of actions

The carcass monitoring program has provided long-term information on population parameters (Lesage et al. 2014b) and causes of death (Lair et al. 2016), and the value of this program for assessing the status of the beluga population has been examined (DFO 2007). This program also provided tissue samples that have allowed monitoring different kinds of toxic chemical compounds (e.g., Lebeuf et al. 2014; see also DFO 2012 for a review), and of other chemical tracers that provided insights into changes in trophic ecology and diet (Nozères 2006; Lesage 2014; Lesage et al. 2017).

The aerial surveys have allowed an age-structured population dynamics model to be built, which enables examining population trends in a biologically meaningful framework (Mosnier et al. 2015). Both population size estimates and recruitment indices from the surveys are used in this exercise. Surveys also provided the necessary information to conclude that there is currently no indication of an expansion or shrinkage of the population's distribution (Gosselin et al. 2014). However, abundance estimates are highly variable and sometimes comprise large uncertainty. This, combined with the small number of estimates obtained due to large time intervals between surveys, reduces the capacity to detect changes in population abundance in a timely manner.

The photo-identification program of the GREMM provided an index of the evolution of recruitment rate over 25 years (Michaud 2014). This data contributed to the validation of model outputs about population dynamics and trends (Mosnier et al. 2015; DFO 2014).

6.2.6.2 Focus of improvements to current and additional monitoring measures

The outcome of the recent DFO review (DFO 2014) of the status of SLE beluga highlights the importance of these monitoring programs in understanding the fate of the SLE beluga population. Therefore, these programs (e.g., the carcass monitoring program, population survey program) should be maintained. However, there are currently very few tools to document changes in health condition or reproduction rate and so there is a need to put in place additional monitoring activities to document these aspects which are key indicators of the sub-lethal and population-level effects of human and natural stressors.