Frequent Questions: Morbidity (Sublethal Injury or Illness) Cases

Will these new North Atlantic Right Whale morbidity (sublethal injury or illness) cases directly trigger specific management actions?  

No, these new morbidity cases do not specifically trigger management actions at this time. This includes existing:

• Take reduction plans
• Stock assessment reports
• List of Fisheries
• Endangered Species Act/Marine Mammal Protection Act permits and authorizations
• MMPA Imports Rule findings

However, the new morbidity cases will inform our conservation and management actions going forward as part of our multifaceted approach to halt the current population decline and recover the species.

For example, morbidity cases may provide an additional indicator as to the impact and prevalence of vessel strikes within the North Atlantic right whale population, and inform our understanding and management of this threat. Morbidity cases are not a required element of stock assessment reports and not counted against the Potential Biological Removal level. However, these new cases may be included in future reports in the discussion of other factors that may be causing a decline or impeding recovery of the stock, including effects on habitat and prey, for North Atlantic right whales. Similarly, while this additional information does not affect the goals of the Take Reduction Plan, these morbidity cases provide insight into the health of the overall population and provide context for considering mitigation measures to reduce mortality and serious injury.

Has the new scientific and veterinary North Atlantic right whale morbidity (sublethal injury or illness) protocol been peer reviewed?

Yes. The Morbidity (Sublethal Injury or Illness) Protocol has been in development for 2 years. It has gone through NOAA Fisheries internal review, an external review with the North Atlantic right whale Unusual Mortality Event Investigative team including Canadian and U.S. partners (governmental and non-governmental), and a final review by the co-authors of the protocol. The Working Group on Marine Mammal Unusual Mortality Events also reviewed the protocol and recommended its adoption.

What does morbidity (sublethal injury or illness) mean?

Morbidity is defined as the condition of suffering from a disease or medical condition. Morbidity is therefore an injury or illness that does not lead to death, but a condition that can reduce or impair well-being including growth and reproduction (i.e., sublethal effects). For the purposes of the North Atlantic Right Whale Unusual Mortality Event, morbidity is defined as a sublethal injury or illness.

What is an Unusual Mortality Event?

An Unusual Mortality Event is defined under the Marine Mammal Protection Act as a stranding event that is unexpected, involves a significant die-off of any marine mammal population, and demands immediate response. Seven criteria determine whether a mortality event is “unusual.” If the Working Group on Marine Mammal Unusual Mortality Events (a group of external marine mammal health experts) determines that an event meets one or more of the criteria, it forwards a recommendation to NOAA’s Assistant Administrator for Fisheries to declare an Unusual Mortality Event.

What is the current status of North Atlantic right whales and the Unusual Mortality Event?

North Atlantic right whales are protected under the Endangered Species Act and the Marine Mammal Protection Act. There are approximately 360 individuals remaining, making them one of the rarest marine mammals in the world. The species has been experiencing an “Unusual Mortality Event” since 2017, which is ongoing. The leading causes of the UME are vessel strikes and entanglement in fishing gear.

More details on the investigation

How has morbidity (sublethal injury or illness) been used in other Unusual Mortality Events?

Morbidity cases or cases of sublethal injury and illness have been included in many previous Unusual Mortality Events involving dolphins, seals, sea lions, manatees, sea otters, and walruses. In UMEs involving these species, the animals were stranded alive and were admitted to rehabilitation hospitals. In rehabilitation, sublethal injuries and illnesses can be treated and the animals in some cases released back to the wild. In these UMEs, the live animals that were admitted to rehabilitation were included as part of the UME, even if successfully treated and returned to the wild.

Why are these morbidity (sublethal injury or illness) cases just being added now, if they have been occurring since the start of the Unusual Mortality Event?

Until now, there has not been a Morbidity (Sublethal Injury or Illness) Protocol that compiles all the various data on sublethal injury or illness cases in near real-time or real-time for North Atlantic right whales. There are data that have been previously available on non-serious injury cases (NARWC report card, scarring analyses, SI reports, etc.). But these reports have had a longer time-lag (i.e., 2–3 year lag) and were not developed for the purposes of a UME investigation. 

In the first several years (2017–2019) of the UME investigation, it became apparent that human interactions (e.g., entanglements and vessel strikes) were the main drivers for this UME. As the UME continued, the investigation team considered how to account for additional cases of free swimming whales with serious injuries due to the same causes as the UME. Following adoption of a protocol to add NOAA Fisheries preliminary serious injury determinations as applicable to the UME, the Working Group on Marine Mammal Unusual Mortality Events added seriously injured whales to the UME in spring 2020. However, at that time the Working Group recognized that there were still sublethally injured and ill whales that were not accounted for in the UME. After subsequent discussion, the UME investigative team determined that adding morbidity (sublethal injury or illness) cases would be beneficial to the investigation to establish the full population impacts of entanglements and vessel strikes during the UME. Over the last 2 years, NOAA Fisheries—along with experts in whale biology and health—developed this peer-review protocol for adding in these morbidity (sublethal injury or illness) cases. Retrospective and prospective cases will be reviewed and added as new data become available.

Will this morbidity (sublethal injury or illness) protocol be used for other small cetaceans or other large whales?

This protocol was developed to be generic enough that the concept and process could be applied to other cetaceans during future UMEs when free-swimming animals show signs of morbidity (sublethal injury or illness; e.g., freshwater lesions in bottlenose dolphins). In those future UMEs, if the morbidity (sublethal injury or illness) was caused by human interaction then some specific criteria (such as laceration depth or length) would need to be modified with the taxa in mind, given size differences. If the morbidity (sublethal injury or illness) was not caused by human interaction then other specific criteria (for example, freshwater lesions) would need to be developed. Additionally, few species are as closely monitored as North Atlantic right whales, so some morbidity criteria may not be able to be evaluated in other species or taxa. 

How are the criteria for scoring morbidity (sublethal injury or illness) in North Atlantic right whales and determining serious injury different or synergistic for the Unusual Mortality Event?

Serious Injury criteria follow the NOAA Fisheries process outlined in the Process for Distinguishing Serious from Non-Serious Injury of Marine Mammals. We interpret the regulatory definition of serious injury (i.e., “any injury that will likely result in mortality,” emphasis added) as any injury that is “more likely than not” to result in mortality, or any injury that presents a greater than 50 percent chance of death to a marine mammal.

Morbidity is defined as the condition of suffering from a disease or medical condition. Morbidity is, therefore, an injury or illness that does not lead to death, but a condition that can reduce or impair well-being including growth and reproduction (i.e., sublethal effects). For the purposes of the North Atlantic Right Whale Unusual Mortality Event, morbidity is defined as a sublethal injury or illness.

The Morbidity (Sublethal Injury or Illness) Protocol is not intended to affect or replace the pre-existing inclusion of confirmed and preliminary serious injury cases within the UME, but rather to expand and add a separate morbidity (sublethal injury or illness) category in this UME to account for sublethal injury and illness cases not currently captured under the UME serious injury protocol. Therefore, the morbidity (sublethal injury or illness) categorization is meant to be separate from, and complementary to, the mortality and serious injury designations already in use for this UME. This will provide a spectrum of health concerns being included in the UME.

What criteria are being used for assessing morbidity (sublethal injury or illness) in North Atlantic right whales for the Unusual Mortality Event?

In general, the morbidity (sublethal injury or illness) classification categories reflect vessel strikes, entanglements, and injuries or poor body condition of unknown cause. These injuries are evaluated from photos or video. Overall morbidity severity for each case is attained by first scoring individual body regions or conditional factors for injury severity, and then combining those scores to determine the overall morbidity severity. Neither body region injury severity nor overall morbidity severity are meant to predict final outcome. Rather, they capture the perceived severity and likelihood of deleterious effects such as infections, energetic costs (e.g., body condition decline), and reproductive consequences (e.g., fecundity decrease). Morbidity evaluations will be conducted on all future cases, as well as retrospectively on cases within the UME timeframe (January 2017 to present).

By evaluating and adding in these morbidity (sublethal injury or illness) cases, we are collating data that has been previously available on non-serious injury cases (North Atlantic Right Whale Consortium report card, scarring analyses, serious injury reports, etc.) but that has had a longer time-lag of at least a year and were not developed for the purposes of a UME investigation. Adding these morbidity cases (sublethal injury or illness) into the UME on a shorter time-frame (e.g., months vs. years) will better inform the UME investigation. These data may aid potential conservation and management actions for animals that have sublethal health impacts which in turn can lead to population level impacts (such as slower growth and delayed reproduction).

Who makes the morbidity (sublethal injury or illness) determinations?

A team of a minimum of three experts conducts the morbidity (sublethal injury or illness) evaluations. The expert cover a range of marine mammal expertise from biology, health, veterinary medicine, anatomy, physiology, pathology, and necropsy. Evaluations are conducted independently and tabulated for comparison across evaluators. When expert evaluations do not agree, the majority opinion is adopted. If there is no majority opinion on the severity categorization (since there are three options there could be a tie), an additional expert is consulted for a majority opinion or a conference call is held to discuss the case and a second round of individual evaluations is done on the case.

Can a morbidity (sublethal injury or illness) determination be reversed the same way an animal with a serious injury that is later sighted alive and well can be reclassified to a non-serious injury?

Whales would not be downgraded or removed from the morbidity (sublethal injury or illness) or serious injury category during the UME investigation. Once documented with a serious injury, sublethal injury, or illness during the UME period, the serious injury or morbidity (sublethal injury or illness) designation captures the likelihood of deleterious effects such as infections, energetic costs (such as body condition decline), and reproductive consequences. These are still relevant for the health of the animal over the time period even if it was later observed to be in an improved condition, with healed wounds, etc.

Will North Atlantic right whale morbidity (sublethal injury or illness) cases be included in stock assessment reports?

Per Section 117 of the Marine Mammal Protection Act, morbidity is not a required element for inclusion in a stock assessment report. However, North Atlantic right whales are a strategic stock. For strategic stocks, stock assessment reports can include information on “other factors that may be causing a decline or impeding recovery of the stock, including effects on marine mammal habitat and prey,” so morbidity cases could be included.

Will North Atlantic right whale morbidity (sublethal injury or illness) cases be counted against Potential Biological Removal?

No. Section 117 of the Marine Mammal Protection Act specifies that only human-caused mortality and serious injuries count against the potential biological removal. These new morbidity cases do not alter risk reduction targets for the Atlantic Large Whale Take Reduction Plan.

How will North Atlantic right whale morbidity (sublethal injury or illness) cases be included in the Take Reduction Team process?

Under Section 117 of the Marine Mammal Protection Act, only human-caused mortality and serious injuries count against the potential biological removal level. Morbidity cases will not affect the goals of the take reduction team or take reduction plan. However, these cases will provide an indicator as to the health of an overall population and provide context for considering mitigation measures to reduce mortality and serious injury.

Will North Atlantic right whale morbidity (sublethal injury or illness) cases be considered in the List of Fisheries?

Not directly. The Marine Mammal Protection Act List of Fisheries evaluates how much mortality or serious injury occurs incidental to commercial fisheries. It does however track non-serious injuries, so there is a chance that a morbidity case may also be considered an “injury” for the purposes of the List of Fisherise.

How will North Atlantic right whale morbidity (sublethal injury or illness) cases be included in the vessel strike risk reduction efforts?

Morbidity cases that involve vessel strikes will provide an additional indicator as to the prevalence of vessel strikes within the North Atlantic right whale population. They will inform our understanding and management of vessel strike impacts on health.    

How will NOAA Fisheries evaluate population level effects from North Atlantic right whale morbidity (sublethal injury or illness) cases and the associated stressors causing them?

As part of the North Atlantic right whale recovery plan implementation team Population Evaluation Tool Subgroup, NOAA Fisheries is evaluating the impacts of various stressors on right whale health, including those that cause morbidity cases, and the subsequent impacts on the population. Population level effects would also be considered in Section 7 consultations on actions that may affect North Atlantic right whales.

Are any Endangered Species Act or Marine Mammal Protection Act permitting or authorization actions triggered based on North Atlantic right whale morbidity (sublethal injury or illness) cases?

No, but they will inform NOAA Fisheries conservation and management actions going forward.

What are the implications of North Atlantic right whale morbidity (sublethal injury or illness) cases for recovery planning?

We will inform the North Atlantic right whale recovery plan Northeast and Southeast implementation teams and these cases may be considered, along with all available information on North Atlantic right whale health and human impacts in working towards recovery.

What are the implications of North Atlantic right whale morbidity (sublethal injury or illness) cases for Species in the Spotlight?

The Species in the Spotlight North Atlantic right whale 5-year action plan for 2021–2025 builds upon existing action, recovery, or conservation plans and details the focused efforts needed over the next 5 years to reduce threats and stabilize population declines. In order to monitor the population, we need to understand right whale habitat, abundance, distribution, and health. Therefore, Species in the Spotlight considers all threats to the subject species. For North Atlantic right whale, the human interaction threats causing morbidity and sublethal impacts are already included in the action plan. 

What are the implications of North Atlantic right whale morbidity (sublethal injury or illness) cases for the Marine Mammal Protection Act imports rule?

The new morbidity determinations have no specific implication on the Marine Mammal Protection Act import rule. NOAA Fisheries is committed to working with Canada through the Marine Mammal Protection Act Import Provisions process to determine whether applicable Canadian fisheries have regulatory programs that are comparable in effectiveness to those governing U.S. fisheries for mitigating bycatch of marine mammals, including right whales.