- website of the Acoustic Ecology Institute
News/IssuesCommunityResourcesSoundscapesAbout UsJoin Us

New NMFS Navy “take” permits: outrageous or reasonable?

Effects of Noise on Wildlife, News, Ocean, Science, Sonar Add comments

The release of Proposed Rules to govern US Navy training and testing operations in the waters of the Atlantic, Gulf of Mexico, Southern California, and Hawaii from 2014-2019 has put the National Marine Fisheries Service (NMFS) in the crosshairs of an outraged response from environmental groups.  NRDC, the Center for Biological Diversity, and others point to the staggering numbers of “Level B” harassment that will be allowed: over 31 million incidents, along with “Level A” injury predictions including permanent hearing loss numbering in the thousands, capped by several hundred deaths.  These numbers reflect far more than sonar training; also included in these permits are impacts from ongoing training and testing of systems used in live gunnery and torpedo exercises, explosive mine-neutralization, air, surface, and submarine battle exercises, and ship-shock trials (in which large explosives are set off near ships to test their resilience).


“We’re talking about a staggering and unprecedented amount of harm to more than 40 species of marine mammals that should give any federal agency involved, be it the Navy or the National Marine Fisheries Service, pause,” NRDC attorney Zak Smith said in a statement.  The take numbers are generally about twice as high as those in the last round of permitting, which covered a five year period from 2009-2013.

“We absolutely share the concern about protecting marine mammals,” said Alex Stone, an environmental program manager with the Navy’s Pacific Fleet. “We think that the mitigation measures are effective, but it’s true, you’re never going to see every marine mammal that’s there. But in terms of impacts on species, we really haven’t seen any of those after years and years of doing these same types of training and testing activities in these same areas.”

“That’s always been a dubious argument but in light of new information it’s wearing especially thin,” said Michael Jasny of the Natural Resources Defense Council, in a KQED segment. “We now know that beaked whales off California are declining precipitously. We know that blue whales aren’t recovering.” Jasny says the Navy should avoid key areas, like gray whale migration routes and the summer feeding grounds of endangered blue and fin whales. “Southern California is a globally important feeding habitat for them,” said Jasny. “It should be elementary common sense to avoid the core feeding habitat of blue whales. “

How could NMFS sign off on such a seemingly devastating number of permitting takes?  Well, as is often the case, the picture isn’t quite as clear as the headlines may make it seem.  Indeed, we are once again thrust into a funhouse-mirror world of wildly divergent ways of framing the proposed plans.  Press releases and resultant popular press headlines trumpet the NMFS rule as “allowing the Navy to harm whales, dolphins more than 31 million times,” with the permitted incidental takes being described as including “a wide range of harms, including destruction of habitat, physical injury and death.”  The Navy’s statement offers a much more sanguine perspective on the tens of millions of behavioral takes, describing these effects as “e.g., turning head, changing swim direction.”  Huh? What to make of all this?

I dug into the Draft EISs and Letter of Authorization requests developed by the Navy, and the two Proposed Rules announced in January, in order to try to understand how Navy and NMFS biologists could have approved the scary numbers.  I came away far less freaked out, though still disappointed that the Navy and NMFS don’t appear ready or willing to keep noisy Navy activities out of some biologically rich areas.  This has been one of the central points of contention pushed by environmental groups for the past few years, and it remains valid to ask why this practical protective step has not been taken, at least regarding explosive activities with a higher risk of injury. (The vast distances over which some of these sounds travel likely means that exclusion zones to avoid behavioral “takes” may need to extend up to 50-100 miles from the regions of concern in order to provide full protection from noise disruptions; the practicality of such large exclusion zones may be harder to establish, though worthy of discussion.)

After a few hours of reading and digesting several hundred pages of environmental analysis and permitting documents, I was able to distill a few of the key take-aways that may help readers to understand NMFS’s reasoning, as well as the shortcomings of the plans.  Click through for my ten-minute version of what’s in these permits.

I was somewhat shocked to find myself more or less convinced by the NMFS analysis of why even the huge numbers of permitted “incidental takes” may truly represent a negligible impact on ocean life, and will highlight some of the reasons below.  But first, I want to zero in on the question of exclusion zones, which will likely continue to be at the forefront of legal and administrative challenges to these permits.  (See earlier AEInews posts here, including coverage of two new 2012 lawsuits)

Exclusion Zones?
Despite several years of administrative input by NRDC and others, and the lawsuits introduced in 2012 challenging the last round of mid-frequency sonar permitting in the Pacific northwest and the current round of global permits for low-frequency sonar, the Navy and NMFS propose only minimal exclusion zones for the next five years of operations.  The Navy and NMFS currently see little additional value in establishing territorial exclusions as a means to reduce injuries; since injury zones for even the largest explosive events (other than a handful of ship shock trials) are on the order of a 100-400 meters for variously-sized animals (though permanent hearing impairment (PTS) may occur out to 1200 meters for the smaller dolphins), with sonar injury and PTS zones being much smaller, they feel confident that existing marine mammal observers and exclusion zones around the active vessels provides the necessary protection.  

In the Atlantic Fleet Training and Testing Area (AFTT), two areas are to be avoided, both important to the critically endangered North Atlantic right whale.  In a calving area off the southeastern US coast, Navy operations will remain 20 miles offshore in some areas, and 10 miles offshore in others, from November 15 to April 15; and in two areas off the northeastern US coast heavily used for foraging, Navy operations will be limited year-round.  Between these two key areas, Navy ships will “practice increased vigilance (and) exercise extreme caution” while transiting the near-shore migration zone. Given the long-range propagation of many Naval noises, the proposed 10- and 20-mile exclusion zones, which include a 5-mile buffer from areas considered crucial to the right whales, are minimal at best to protect from behavioral disruption and related stress responses.

In the Hawaii-Southern California Training and Testing (HSTT) study area, only a single Humpback Whale Cautionary Area, established in 2008, is mentioned.  This is an area where humpbacks congregate in winter and early spring for calving and mating.  Here, training is not excluded, but can only occur with authorization from the Commander of the US Pacific Fleet; the NMFS rule stresses that such approval is rarely requested or granted, and that “the Navy has, for more than 40 years, routinely conducted Anti-Submarine Warfare (ASW) training in the waters off the Hawaiian Islands, including the Humpback Whale National Marine Sanctuary. During this period, no reported cases of harmful effects to humpback whales attributed to MFAS use have occurred,” while populations have risen.

That’s the extent of actual semi-exclusion zones.  The AFTT Rule also notes five planning awareness areas (PAAs; black hashed areas in map above), “based on locations of high productivity that have been correlated with high concentrations of marine mammals (such as persistent oceanographic features like upwellings associated with the Gulf Stream front where it is deflected off the east coast near the Outer Banks), and areas of steep bathymetric contours that are frequented by deep diving marine mammals such as beaked whales and sperm whales. For events involving active sonar, the Navy would avoid planning major exercises in planning awareness areas when feasible.”  No such PAAs are noted in the HSTT Rule.

NMFS also notes its new Cetacean and Sound Mapping effort, but defers on placing any limits on Navy activities in the Biologically Important Areas (BIA) that have been identified so far.  While stressing that BIA designation alone would not preclude Navy activity (and any restrictions would need to go through a NEPA process), NMFS notes that so far, BIAs have only been published for the Arctic Slope and Hawaii.  In Hawaii, “NMFS has reviewed the Navy’s exercise reports and considered/discussed their historical level of activity in the area where these resident populations are concentrated, which is very low, and concluded that time/area restrictions would not afford much reduction of impacts in this location and are not necessary at this point.”  NMFS notes in both the AFTT and HSTT Rules that as more BIAs are designated, “we may need to discuss whether additional protective measures might be appropriate.”

Other than these modest (some would say woefully inadequate) exclusionary measures, Navy training and testing activities can proceed in any and all areas off the east coast of the US and Gulf of Mexico, and in the large areas included in the HSTT study areas off the coast of southern California and Baja California, around Hawaii and west to the International Date Line, and the transit zone between SoCal and Hawaii.  Expect to see this as a key factor in legal challenges to come.

What about those huge numbers of takes?
There’s no doubt that the estimated (and permitted) “take” numbers are alarming.  One of the major things we’ve learned over the past decade is that behavioral disruptions caused by moderate noise levels (from ships, airguns, or Navy activities dozens or a hundreds or more miles away) are more likely to have population-level impacts than the much rarer, very close exposures to loud noise that can cause injury or death.  In fact, the current leading-edge concern is that chronic stress from this ongoing exposure to both increased ambient background noise and repeated reactions to transient noises is almost inevitably having deleterious effects on individual and group health, reproduction, and resilience to other challenges, such as disease or food shortages.  So, how can NMFS allow such widespread exposure to Navy noise?

Several overarching themes help explain NMFS’s reasoning.  I don’t intend here to make a claim one way or the other as to whether these ways of thinking about it actually reflect risk being reduced to acceptable levels; I’ll leave that to the scientists and lawyers.  But here’s what underlies the assessment by both NMFS and the Navy that this five-year plan won’t decimate the ocean environment.

First and perhaps foremost is that most of these Navy activities have been ongoing for decades, with no readily apparent widespread impact on populations, and very few deaths.  Some part of the increase in take numbers in this round of permitting reflects the expansion of the area and activities being considered in the studies, along with improved data on both population distributions and the extent of (often subtle) behavioral responses.  In some cases, response thresholds have been reduced in the wake of recent research, which increases the number of animals exposed.

However, the new plans also propose some substantial increases in Navy activities. The Draft EISs assess a No Action Alternative that carries present activities forward unchanged, along with Alternatives 1 and 2 which each increase activities, with Alternative 2 having slightly larger increases, and being designated the Preferred Alternative; it is Alternative 2 that is receiving NMFS blessing in the form of the Proposed Rules.  By and large, sonar training levels remain close to what they’ve been, especially on submarines, though training and testing with the newish sonobuoy technology (which is another loud acoustic source), including deployment from helicopters, will be doubling or more in some areas.  Larger increases are projected in many gunnery and explosive training activities, many of which are doubling, and some of which are increasing up to ten-fold.  This leads to significant increases in estimated “takes” as well: behavioral take estimates generally triple for training activities between the No Action Alternative and either Alternative 1 or 2, and increase by 2x-8x for testing; TTS (temporary hearing impairment) increase dramatically (3x-10x) as well when moving from present levels of training/testing to Alternative 1 or 2, with PTS (permanent hearing impairment) also rising markedly.    Surprisingly, both the AFTT and HSTT Draft Environmental Impact Statements predict the impacts on marine mammals will be no different in any of the three alternatives being assessed. 

How can 30 million behavioral disruptions be no more of an impact than 10 million? How can three to ten times as many TTS events, or four times as many PTS events, not be more troublesome? The answer lies partly in the fact that NMFS is here assessing “the overall fitness of (each) marine mammal population,”  rather than strictly the numbers of animals affected.  But the heart of the answer rests in the assumption that most of the counted impacts either won’t occur, or will be of no more than modest significance for the individuals affected.  NMFS bases their finding of no significant impact on several main reasons:

  • First, the take numbers are based on predicting sound levels around Navy activities, into waters where animal population distributions are modeled based on what is known about regional populations.  The take numbers do not account for animals moving away from sound sources, or for some of the mitigation measures taken by the Navy to minimize impacts (including holding off on noise-making activities when animals are dangerously close). It may seem strange to estimate takes prior to avoidance and mitigation; the reason is that we don’t have reliable ways to quantify either of these effects.  While it may be reasonable to assume both will be strongly in play and will reduce the number of impacts, at least of injuries, we can’t (especially for legal purposes) make solid predictions that take these into account.
  • Second, the vast majority of behavioral impacts (around 70%) are predicted to occur at sound levels of roughly 150-162dB, which corresponds to distances of 37-75km.  These are expected to be very minor behavioral changes, and, since most Navy activities occur on the scale of hours, the presumption is that changes in behavior (even the more rare substantial impacts such as abandoning foraging) will have minimal impact if they are short-term.  (Ed. note: A possibly weak point in this argument is that while the Navy and NMFS assume that “a few behavioral reactions per year, even from a single individual, are unlikely to produce long-term consequences for that individual or the population,” there is little quantification of likely repeat exposures.  In the Pacific areas, 95% of the behavioral impacts are concentrated in the Southern California ranges (because of the large populations of many species there), suggesting that many animals could be repeatedly exposed; the vast majority (about three-quarters) of these behavioral impacts will happen during major multi-day exercises.  This concentration of the effects could be better for the animals (a few days of disruption amidst long periods of little noise), or worse for them (keeping them from normal activity for days at a time).  These energy-budget questions are very hard to quantify and assess, and so far, it appears that NMFS and the Navy are largely relying on an assumption of minimal effects from cumulative or repeated disruptions.)
  • Considering hearing loss, two things are important to bear in mind.  It’s easy to take the phrase “permanent hearing loss” to mean total deafness.  In fact, as in humans, both permanent and temporary hearing loss actually manifests in degrees.  Because animals will move away from loud (especially painful) sounds, and the sources of the sounds (especially sonar) are themselves in motion, it is expected that any PTS (permanent threshold shift) that occurs will be moderate.  As in humans, this would mean you can’t hear as well, or that ambient sounds and calls “sound” softer or muddier than they would otherwise; complete deafness is not likely.  Likewise, as in humans, some hearing loss occurs naturally and animals seem to adapt to it.  It’s also worth noting that the PTS threshold is reached only at very close distances: 10m for medium-sized whales and dolphins, 67m for larger whales, 100m for dolphins and porpoises, for the “most powerful” acoustic systems. In addition, in both PTS and TTS (temporary threshold shift), the injury caused by sonars is very frequency-specific, affecting only a small portion of the animal’s hearing and communication range.  It’s unlikely that losing a sliver of the hearing range would be debilitating. (Ed. note: I’m less clear about whether effects would be similarly limited from explosions, which are likely far more broadband than sonar signals; explosions can also be louder than sonars, thus leading to PTS onset ranges of up to 475m for smaller dolphins, and 150-250m for larger whales. In the AFTT in particular, well over half the Level A takes, primarily injuries including PTS, are predicted to come in four ship shock trials over the five years; for these huge explosions, PTS can occur as far as 5-10km for smaller dolphins and 1-5km for larger whales.)
  • As for physical injuries, the Navy models are extremely conservative.  Tissue injury thresholds (for things like lung injuries or death of those near explosions) are set at levels that reflect the body mass of a newborn calf of each species, and at which 1% of animals thus exposed are expected to sustain the injury.  Obviously, this greatly over-predicts actual injury rates of the population as a whole.  Likewise, while many explosions of ordnance occur on impact with above-water targets, for simplicity and conservative predictions, the sound models all are based on that explosion occurring 1 meter below the surface, again creating a significant over-estimate of the extent of blast trauma.

For all these reasons, NMFS concludes that actual injuries and deaths will be far fewer than the numbers in the permits suggest, and that behavioral impacts will be generally transient and insignificant.

Of course, the very fact that these EISs and permit documents so dramatically quantify the numbers of animals that will hear, and react in some way, to Navy activity – and reveal the vast distances at which some of these effects occur – is a graphic illustration of the scale at which human activities are affecting the ocean environments.  There is no similar assessment of the impacts of the ocean-spanning web of large container ships; likewise, the sounds of airgun arrays from over a hundred seismic survey vessels worldwide receive only minimal scrutiny, though they are as loud as most of the loudest Navy activities, and so also propagate for dozens to hundreds (and at times even thousands) of miles, while operating around the clock for weeks at a time in many regions.  

Ever since the strandings that occurred in the late 1990’s and early 2000’s around some sonar training missions, and the resultant legal action that triggered the Navy to begin applying for permits for its activities, the public, regulatory, and legal spotlight on Navy activities has fueled our growing understanding and appreciation for the effects of human noise in the ocean (and Navy research funding has been a major driver of our increasingly detailed understanding of acoustic impacts).  While NMFS may indeed be correct that the proposed suite of Navy training and testing activities won’t cause any appreciable additional impact on ocean life, by looking at it that way, we are apparently succumbing to the reassuring idea that whales, dolphins, sea lions, turtles, fish, and crustaceans are simply able to live with our noise, and make the best of it.  Perhaps so, but that doesn’t make it any less discouraging.

To learn more:

See links at the top of this post for press releases and press coverage from environmental advocates. Also:
Center for Biological Diversity ocean noise page
Natural Resources Defense Council sonar page 

HSTT documents:
Navy HSST website, with links to DEIS
Navy Request for HSTT Letter of Authorization
NMFS Proposed HSTT Rule

AFTT documents:
Navy AFTT website, with links to DEIS
Navy Request for AFTT Letter of Authorization
NMFS Proposed AFTT Rule

Navy technical reports:
Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis Technical Report
Determination of Acoustic Effects on Marine Mammals and Sea Turtles 

Comments are closed.