Crustaceans need ears too!

A preponderance of marine bioacoustic work has been focused on marine mammals – whales, dolphins, and pinnipeds. This is in large part due to the “charismatic megafauna” paradigm where big, complicated animals with recognizable expressions attract most human interest.

While fish – particularly large or colorful species can capture our attention under this same rubric, most scientific research on fish is advanced due to their commercial importance. Critters further down on the ‘charisma scale’ even while equally complicated in their adaptations are typically not studied, so it was great to hear OCR pal and Biologist Erica Staaterman’s presentation on mantis shrimp at the recent “Acoustic Communication by Animals” Symposium.

Even better was that her work was picked up by “Science Daily” and distributed to a wider public.

The mantis shrimp are visually intriguing; being some 8” to 10” (and up to 15”) long with a pair of incredibly complicated eyes that can sort out twelve colors and reconcile polarized light. Some species visually communicate by modulating fluorescence on their bodies, and some species live in monogamous pairs for up to 20 years!

With all of these attributes it is likely that vision is their dominant perceptual adaptation, but Erica found that they also communicate with sound through a low frequency rumble or purr. In the realm of human perceptions this isn’t Grammy material, but when pitch-shifted up an octave the call and response patterns become more apparent.

She also found that listening to the shrimp was very different in the wild from listening to them in a tank. The shrimps’ communications were, “so synchronized they sounded like a chorus.”

We can only speculate what they are expressing with these sounds, but Erica’s work has rolled back just a little more of the mystery of the deep. [Read Ocean-Noise post on ‘chorusing’]

Her paper was published in Aquatic Biology.

Report from the International Quiet Ocean Experiment

Last week I attended the “International Quiet Ocean Experiment” (IQOE) at the UNESCO headquarters in Paris. The founding premise of the meeting is a bit outrageous – that somehow all maritime nations could come together and halt all of their ocean noise-making activities for some short period of time to observe the effects of this military-industrial silence on marine life.

Of course the idea of halting some 50,000 ocean transport vessels, all navies, marine petroleum operations, fishing fleets, mining and dredging, energy projects, underwater communications, pleasure craft, and seismic exploration is absurd. But the true incentive behind this improbable assertion was to bring together leading scientists and policy makers, explore our concerns, and devise a ten-year plan to understand and mitigate the impacts of anthropogenic noise on ocean life.

This first gathering represents a huge step in the right direction. When the issue first came up in he early 1990’s there was little consensus on anything. The geological-scale experiments at the time were being conducted by physical oceanographers who frankly did not understand biology; the biologists involved had forgotten their physics, and most of the work was being funded by the biggest noise-makers – whose priorities were not focused on conservation.

The IQOE discussions explored many topics, including observing systems technologies, the meaning of “ocean soundscapes,” what science is needed, how to conduct informative experiments, and how to measure the long-term and synergistic impacts of noise on marine life.

Many fine ideas were advanced and new thinking was cultivated which will help direct research and mitigation strategies for the next decade. There was a remarkable climate of collegiality and collaboration, and if there was any serious contention at the end of the day it was about the name – which we all agreed was an unlikely conceit. But using the name as a “branding” or marketing ploy really got under the fingernails of some of the scientists.

The name may change (although I doubt it), but we will keep you informed as the framing documents are issued and the project progresses.

Stay Tuned!  More details to come.

Michael Stocker

The Neutrino and the Whale

photo: Brain Skerry

photo: Brain Skerry

A nicely written article in the Dec. 3 2009 issue  Nature reveals how a how a neutrino detection experiment conducted in the Mediterranean Sea by nuclear physicists actually uncovered an abundance of sperm whales.

The experiment involved placing hydrophones down 2000 meters below the surface; the idea being that these hydrophones could detect little pops from neutrinos – sub-atomic particles zipping in from deep space.

Marine Biologists Giovanni Pavan was brought in to help filter out the background noise. What they found though was a proliferation of biological sounds, and a surprising high density of Sperm Whale vocalizations – which ended up shifting the focus of the study to monitoring populations of sperm whales.

The article mentions that the Nuclear Physicists somehow thought that the deep ocean would be a “quiet test chamber” for their studies. I find it telling that some of the smartest guys in the room (nuclear physicists) would be so siloed in their field that they would lose track of the fact that the ocean is teaming with ‘biologicals.’

This speaks volumes about our education model that focuses on specialization. It makes me worry about what I am missing when I scan the field I inhabit. But this tale also helps me cultivate more patience for those folks who “can not seem to grasp” the importance of our mission of preserving the ocean’s bio-acoustic sanctity.

This little sound sample is of the “carpenter fish” – an old mariner’s name for sperm whales, representative of what the scientists heard.

Dust-up (and Follow-up) on seismic surveys in Juan de Fuca

Hydrothermal Vent

EcoJustice is asking for hearings about a proposed geological survey of the Endeavour Hydrothermal Vents Marine Protected Area. There is some irony in conducting seismic surveys in marine protected areas, particularly an area that has been recognized as a habitat for “12 species of marine life that do not exist anywhere else.”

Sabine Jessen from the Canadian Parks and Wilderness Society pointedly comments “If marine animals can’t find safety in the few areas set aside for them, where will they find it?”

The article from the Canadian Times Colonists was sent to us by a colleague at NSF and can be found here.

Perhaps as informative about the issue are the comments by the mostly Canadian citizens following the article. Equal parts bluster and concern, it illustrates the need for more public understanding about the impacts of seismic surveys on marine life.

There seems to be a divide between those who believe that there is no evidence that seismic surveys harm marine animals, and those who may not have the evidence but instinctively believe that repetitive seismic impulses are inherently bad for marine life.

Many comments are in the tradition of ad-homonym attacks (which I find surprising for Canadians). The comments also do not consider the new data substantiating that seismic surveys do have biological impacts on marine mammal foraging behavior at distances greater than 10 km (Jochens, et al, 2008, Southall et. al. 2007), and have been correlated with a cessation in traditional migratory behavior at distances greater than 100km in Mediterranean Sei whales (Castellote, 2009). And of course there is the well established evidence that seismic surveys compromise fisheries.

This particular scrap is a little uncommon because the antagonists are scientists, not the usual fossil fuel industries or the military. It also illustrates the priority rift between geophysical sciences and biological sciences – and the inherent problem with scientific specialization.

The geophysicists want to know more about tectonics in this lively area full of hydrothermal vents. The area is host to unique species, perhaps because of the hydrothermal activity. Should we compromise the unique life here to find out about its tectonic structure? Or should we take a broader and longer view of the area as a unique global habitat?

Of course all of the scientific data is “important,” but if it is not considered in a larger systematic context it loses relevance.

Follow-up on the Dust-up:

Director of Acoustic Ecology Jim Cummings reviewed this issue in greater depth and reports that the survey ship did go through an Environmental Assessment with National Marine Fisheries Service (NMFS) which concluded that the potential impacts of the project have been well considered.

For me his most persuasive statement Is “Throwing up legal roadblocks to a carefully designed, ten-day seismic shoot is a very extreme reaction, and should be reserved for times and places where there is real danger of harm.”

A similar situation occurred a few years back when Peter Tyack and Peter Stern were attempting to conduct “controlled exposure experiments” on migrating grey whales in California.

In this case the “defense” team took issue with a calibration beacon that sent out a single-frequency signal that would hardly be detectable over the noise of the research vessel engines.

This case drove a wedge between the scientific community and the conservation community that took years to heal, and compromised the acquisition of information that would prove very useful for more important conservation efforts.

Perhaps EcoJustice is taking advantage of the irony of doing seismic testing in a marine protected area.

As in the case of scientific data, any legal precedent is “important,” but if it is not considered in a larger systematic context it loses relevance.

Jim’s article can be found here.

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