Category Archives: Sound and sonar

Mass Dolphin Deaths in Peru Caused by Acoustic Trauma

Mass dolphin deaths in Peru caused by acoustic trauma

 [Photo-Image: Dead dolphins discovered on Chiclayo shore of Peru, Photo source: ITN News]
[Photo-Image: Dead dolphins discovered on Chiclayo shore of Peru, Photo source: ITN News]
Dr. Carlos Yaipen Llanos of ORCA in Peru informed Hardy Jones of Blue Voice that acoustical trauma is the cause of the Mass Mortality Event (MME) that killed an estimated one thousand dolphins along the coast of northern Peru in March 2012.
In her article, Hundreds of dead dolphins wash up along the coastline in Peru, Elizabeth Batt describes the devastating loss of the dolphins and porpoises, and the swift action by filmmaker and author Hardy Jones to document the event.
Now the necropsy results are in, and there is unequivocal evidence that the dolphins were killed by an acoustic trauma, such as loud sonar or explosive blasts (more information on potential sources of the loud sound in that region can be found here). Dr. Llanos doesn’t identify the source of the trauma, but all other tests (virus, contaminants, parasites etc) are not considered factors.
The following tissue samples, provided to Blue voice by Dr. Llanos show evidence of rapid ascent, (though the scientists are not willing to speculate on what caused the dolphins to race to the surface, their bodies are adapted to adjust to depth, and normally do not aggregate bubbles in their tissues).
Bubbles replaced normal tissue in the dolphin’s liver.
Blue Voice


 bubbles 2
A large bubble is compressing a vein and artery in this dolphin’s bladder.
Blue Voice
bubbles 3
The jaw blubber of this baby porpoise is spread by bubbles. The blood vessels show congestion and hemorrhage.
Blue Voice
Necropsies were performed on site. Macroscopic findings include: hemorrhagic lesions in the middle including the acoustic chamber, fractures in the periotic bones, bubbles in blood filling liver and kidneys (animals were diving, so the main organs were congested), lesion in the lungs compatible with pulmonary emphysema, sponge-like liver. So far we have 12 periotic samples from different animals, all with different degree of fractures and 80% of them with fracture in the right periotic bones, compatible with acoustic impact and decompression syndrome.
In a February stranding in the same region of Peru, Dr. Llanos found that:
10 of the 17 animals found dead had broken periotic bones, that is, due to acoustic impact. The source of the impact was from the right side of the pod, since hemorragic internal ear was found in the right side of the stranded animals.
We know that the use of dynamite is common among fishermen, and that fishermen are taking the meat of the stranded dolphins. This could be the cause of death of the animals…however, the signs do not correspond to that of explosive impact in their bodies. We talked today with people from the oil company and they say they haven’t performed any seismic exploration in the area this month. However, here in Peru these companies don’t need to do the seismic assessment themselves.
Update 5/18/12 : Dynamite has been ruled out as a possible cause (via Hardy Jones),
To compare with some of the stranded dolphins Dr. Llanos examined the remains of healthy dolphins that had been stabbed at sea and eaten by the local fishermen and found “intact periotic (ear) bones, (with no fractures), so it was a good “control” sample to compare with previously collected (and fractured) ones.”
Hardy Jones explained to Digital Journal that “traveling to and within Peru is expensive and testing samples from the dead dolphins is very costly, yet highly important.” Blue Voice and Dr. Llanos (ORCA) will continue to investigate the mortality event, and will post updates.

These whales can avoid Navy sonar from ships but not from helicopters – public opinion sought on Naval exercises

A recent Navy-funded research paper on Cuvier’s beaked whales and military sonar reveals that in one location these whales have learned coping strategies to avoid ship-mounted sonar – but those strategies can only go so far to protect them.

The whales’ behavior is nuanced and more complex than previously known, which demonstrates their remarkable intelligence and adaptability.

The longest deep dive in this study, lasting 163 min, occurred while the whale was intermittently exposed to mid-power MFAS at distances of 8–12 km.
While it may be possible for a whale to avoid conducting a deep dive while a surface ship is nearby, the same is not true for helicopters, which acoustically may appear without warning. Surface ships typically broadcast MFAS for extended periods while moving; thus whales probably know roughly where the ship is when exposure begins and how the ship’s position is changing through time, and can use this knowledge to mediate their response.
Helicopters deploy MFAS from a hover in bouts generally lasting under 20 min, moving rapidly between sequential deployments in an unpredictable pattern, and thus whales may react more strongly to these sudden, close-range exposures even though their duration of use and source level (217 dB) are generally well below those of a ship’s MFAS (235 dB) [27]. The difference in these responses underscores the importance of how the source is used, in addition to sound levels (source or received) and distance, in predicting whale behaviour, particularly for whales that are probably familiar with both MFAS types.

This study suggests that while these whales recognize Navy vessels and have adopted a suite of behaviors to avoid the sonar, they may be impacted by the unpredictable nature of aerial sonar. Long term, the avoidance behaviors may accumulate into loss of sustainability.
The paper is publicly available online, below is the abstract. Diving behaviour of Cuvier’s beaked whales exposed to two types of military sonar:

Cuvier’s beaked whales (Ziphius cavirostris) have stranded in association with mid-frequency active sonar (MFAS) use, and though the causative mechanism linking these events remains unclear, it is believed to be behaviourally mediated. To determine whether MFAS use was associated with behavioural changes in this species, satellite tags were used to record the diving and movements of 16 Cuvier’s beaked whales for up to 88 days in a region of frequent MFAS training off the coast of Southern California.
Tag data were combined with summarized records of concurrent bouts of high-power, surface-ship and mid-power, helicopter-deployed MFAS use, along with other potential covariates, in generalized additive mixed-effects models. Deep dives, shallow dives and surface intervals tended to become longer during MFAS use, with some variation associated with the total amount of overlapping MFAS during the behaviour.
These changes in dives and surface intervals contributed to a longer interval between deep dives, a proxy for foraging disruption in this species.
Most responses intensified with proximity and were more pronounced during mid-power than high-power MFAS use at comparable distances within approximately 50 km, despite the significantly lower source level of mid-power MFAS.
However, distance-mediated responses to high-power MFAS, and increased deep dive intervals during mid-power MFAS, were evident up to approximately 100 km away.

Cuvier’s beaked whale (Whaleopedia) 
As a result of similar research, the Navy is asking for your opinion on changes that are planned in the training areas off the Pacific Coast states. They are proposing changes to the environmental impact statements that are required for them to detonate explosives during practice sessions, and will consider new data (such as more accurate measures of marine mammal hearing levels) – there is even the option to scrap the practices altogether, although the latter is unlikely given the saber-rattling going on in the world at this time.
In California and Oregon the changes will only apply outside of state waters, but in Washington they will include inland waterways such as Puget Sound.
The question is, are these proposed changes good or bad for the whales and dolphins that live in these waters? At this point the Navy continues to practice maneuvers in the Olympic Coast National Marine Sanctuary, and Navy sonar is so loud around the San Juan Islands that it can drown out the calls of the orcas on the hydrophones put in place to monitor whales.
The Navy is dedicated to keeping us safe from enemies at our shores, and they are also answerable for needless destruction caused by the need to practice – a tricky balancing act…but they are trying.
Below is the basic information on the Navy’s planned changes. 
In the supplement to the 2015 Final EIS/OEIS, the Navy will analyze training and testing activities within the Study Area. The Study Area remains unchanged since the 2015 Final EIS/OEIS and includes:

  • Established maritime operating areas and warning areas in the northeastern Pacific Ocean, including areas within the:
    • Strait of Juan de Fuca
    • Puget Sound
    • Western Behm Canal in southeastern Alaska
  • Air and water space within and outside Washington state waters
  • Air and water space outside state waters of Oregon and Northern California
  • Navy pierside locations

Navy Acoustics

KEY UPDATES TO THE 2015 FINAL Training and Testing Final Environmental Impact Statement/Overseas Environmental Impact Statement (EIS/OEIS ) and why it needs your input on proposed supplemental information. (Comments can be submitted here).

Training and testing activities proposed in the Supplemental Statements are generally consistent with those activities analyzed in the 2015 Final Statement and earlier environmental planning documents.
Below are some key updates to be made. In the Supplemental Statement, the Navy will:
• Include a No Action Alternative in which proposed training and testing activities would not be conducted and Marine Mammal Protection Act authorization would not be issued by National Marine Fisheries Service (NMFS)
• Include analyses of increases in testing of some new vessels and weapons systems, and decreases in other testing activities
• Include analyses of both increases and decreases in the annual occurrence of certain activities
• Recategorize or rename some testing activities to be consistent with Navy testing activity categories
• Include improved acoustic models, updated marine mammal and sea turtle densities, and updated marine species criteria and thresholds based on NMFS’s 2016 guidance
• Use the most current and best available science and analytical methods
• Review procedural mitigations, where appropriate, and consider geographic mitigation, where applicable
The Supplemental Statement will include an analysis of training and testing activities using new information available after the release of the 2015 Final Statement. New information includes an updated acoustic effects model, updated marine mammal density data, and evolving and emergent best available science. As part of this process, the Navy will seek the issuance of federal regulatory permits and authorizations under the Marine Mammal Protection Act and the Endangered Species Act to support ongoing and future at-sea military readiness activities within the Study Area beyond 2020.
The 30-day scoping comment period begins Aug. 22, 2017 through Sept. 21, 2017. Comments must be postmarked or received online by Sept. 21, 2017 for consideration in the development of the Draft Supplemental EIS/OEIS. Comments may be submitted online at, or by mail to:
Naval Facilities Engineering Command Northwest
Attention: NWTT Supplemental EIS/OEIS Project Manager
3730 North Charles Porter Ave., Building 385
Oak Harbor, WA 98278-3500

Seismic surveys now proven to kill zooplankton…there goes your crab dinner

Like many marine fishes, this baby puffer fish drifts with the ocean currents during its larval stage

Love lobster? Crab? Swordfish? The larvae (just hatched) stages of these tasty marine species spend their early development floating as part of zooplankton community. Their limited ability to move means that they drift wherever the currents take them, leaving them uniquely vulnerable and unable to escape devastating events such as oil spills or even just the noise associated with searching for new offshore oil reserves.
Baby sailfish

Published today in Nature, the science is in – the noise from the airguns used in seismic exploration for offshore oil has been shown to have devastating effects on zooplankton. The team of researchers found significant damage to zooplankton up to 3/4 mile away from the source:

Experimental air gun signal exposure decreased zooplankton abundance when compared with controls, as measured by sonar (~3–4 dB drop within 15–30 min) and net tows (median 64% decrease within 1 h), and caused a two- to threefold increase in dead adult and larval zooplankton.

Lobster larvae

Impacts were observed out to the maximum 1.2 km range sampled, which was more than two orders of magnitude greater than the previously assumed impact range of 10 m. Although no adult krill were present, all larval krill were killed after air gun passage.
There is a significant and unacknowledged potential for ocean ecosystem function and productivity to be negatively impacted by present seismic technology.

Octopus larva

The significance and implications of potential large-scale modification of plankton community structure and abundance due to seismic survey operations has enormous ramifications for larval recruitment processes, all higher order predators and ocean health in general.
There is an urgent need to conduct further study to mitigate, model and understand potential impacts on plankton and the marine environment, and to prioritize development and testing of alternative seismic sources.

Swordfish larva

Plankton also supply half of the oxygen we breathe and are the base of the ocean food web – with less plankton there is less for fish to eat at a time when the world is increasingly looking to the ocean to provide food.
The planned seismic surveys off the Atlantic Coast of the US will have negative effects on the marine life, and eventually will impact the distribution and abundance of seafood. And if you like to fish, you may find it even harder to hook a big one.
NOAA is taking comments until July 6th on the proposed seismic surveys in the Atlantic.
Blue marlin larva


Legal Action Taken to Protect Whales From Atlantic Oil Exploration in response to Trump’s Executive Order

President Trump issued an executive order Friday calling for the Department of the Interior to review its 2017-2022 offshore oil and gas leasing plan and all restrictions on offshore energy production, possibly opening up the Atlantic, Arctic and Pacific oceans to dangerous offshore drilling projects. Administration officials also said seismic testing in the Atlantic, which was removed from the final five-year plan, could proceed during that review.

WASHINGTON— Conservation groups have moved to intervene in an administrative appeal by the oil industry challenging a federal decision to reject six oil and gas exploration permits for the Atlantic Ocean. The Bureau of Ocean Energy Management denied the seismic airgun survey applications in part because the loud blasts would hurt endangered North Atlantic right whales and other sensitive wildlife.
In denying the permits, the Bureau found that the “small, critically endangered, and declining population of” North Atlantic right whales, which recent surveys say include an estimated 476 whales, “would doubtless be disturbed by seismic activity.”

“Seismic blasts are so loud they can injure endangered right whales and other marine mammals. We’ve been working to save right whales from extinction, and we’re intervening in this appeal to ensure the safety of these rare whales from oil and gas exploration,” said Kristen Monsell, an attorney with the Center for Biological Diversity.
Seismic exploration surveys use high-powered airguns to search for deposits of oil and gas. They generate the loudest human sounds in the ocean, short of explosives. The blasts, which can reach more than 250 decibels, can cause hearing loss in marine mammals, disturb essential behaviors such as feeding and breeding over vast distances, mask communications between individual whales and dolphins, and reduce catch rates of commercial fish.
In addition to the Center for Biological Diversity, today’s motion was filed by the Natural Resources Defense Council (NRDC), North Carolina Coastal Federation, South Carolina Coastal Conservation League, One Hundred Miles and Defenders of Wildlife. The groups are represented by attorneys from NRDC, the Center and the Southern Environmental Law Center.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.3 million members and online activists dedicated to the protection of endangered species and wild places.