Noise impacts on fish and invertebrates workshop

I spent last week in San Diego attending a workshop sponsored by the Bureau of Ocean Energy Management (BOEM) on the impacts of human generated noise on marine fish and invertebrates. Having watched the field of ocean noise impacts roll slowly forward in fits and starts for 20 years, this workshop is really a breath of fresh air (or a gulp of fresh water).

Most of what has driven the ‘noise impacts’ discussion over the years has been concern for marine mammals – both from regulations such as the Marine Mammal Protection Act and Endangered Species Act, and from the concerns of the public for the critters that are called “marine charismatic megafauna” in the conservation business.

Of course the ocean is much more than a menagerie of iconic animals; it also includes a vast portion of the biota – from the simplest bacteria and archea to the most complex communities of fish, invertebrates, and marine mammals – upon which all life on earth depends.

We have afforded a modicum of protection for some members of this menagerie with regulations because they inspire us or feed us. But our regulatory frameworks do not protect all of the animals which are impacted by noise and that make up the web of ocean life.

This is why the BOEM workshop was so exceptional. It brought together many of the world’s experts on marine bioacoustics to spend a few days digging down into our concerns and understandings about the impacts of noise on the less charismatic, but nonetheless equally important members of the animal kingdom found in the sea.

Giant squid beached coincident to seismic surveys

Giant squid beached coincident to seismic surveys

BOEM’s objective falls under the recent “ecosystem based management practices” advanced by NOAA Director Jane Lubchenko “to make non-arbitrary management decisions that are scientifically informed.” Our objective as attendees was to form a basis of understanding and inquiry that informs BOEM about impacts of noise on the diverse species of marine fish and invertebrates.

While this meeting did not solve all of the ocean’s acoustic mysteries, it provided a substantial opening to bring biologists, acousticians, physicists, and engineers together to work toward common strategies on understanding and decreasing our acoustical impacts on marine life.

After a decade of inaction on federal ocean policy, this is really something to celebrate.

What the Ocean Provides

In the current issue of Orion Magazine there is an article about animal intelligence and the octopus that is worth a read. It is pretty much out in the field of common knowledge that these animals are remarkably intelligent. Most folks have heard one tale or another about an octopus sneaking out of their aquarium at night to pull off some mischief.

The article excavates a bit deeper into the super-perceptions of these denizens; how they can probably “taste emotions” through chemo-sensor skin.  Their skin also has photo-receptors allowing the skin to “see,” and thus brilliantly adapt their coloration and even texture as a form of expression or method of camouflage – which they can do with flair and “personality.”

Bishes Rochon by Norman Wu

Bishes Rochon by Norman Wu

The Octopi are mollusks, sharing the phylum with snails and slugs – which seems a bit counter-intuitive. This is reconciled somewhat by their separate classification as “cephalopods” or “head foots” (along with the cuttlefish and squids) whereas the snails and slugs are “gastropods” or “stomach foots.”

What may account for their adaptive intelligence is that their nervous systems are a balance between a central nervous system (that vertebrates like us have) and a distributed nervous system (like insects have). Both systems have advantages. By centralizing our processing, our senses report back to our brain – which learns a repertoire of responses and can fine-tune and adapt over time in ways consistent to our learning.

Camoflaged Octopus by Colin Zylka - Marine Photobank

Camoflaged Octopus by Colin Zylka - Marine Photobank

Distributed nervous systems on the other hand have ganglia and neurons where they are needed, so the grasshopper’s brain doesn’t need to decide to jump, the legs just jump when some threshold is triggered. One advantage of this is in speed or impulse response; neural communications are not bogged down by pondering.

By having a combination of central and distributed neurological functions the octopus can learn, and adapt fast. So when you see these animals work on a problem it appears as if their arms are doing the thinking.

With super-sensing skin, a poisonous bite, rapidly adaptive coloration and texture, distinct individual personalities, and an uncommon ability to sort things out, what do these animals hear?

It turns out that they hear nothing – or at least they don’t let on to hearing anything. This is a bit uncanny given how useful sound perception would be to an animal with the octopus’ intelligence, adaptability, and sensory compliment. But they seem to be deaf as a stone.

The Ocean provides the octopus for us to get to know, but she also provides mysteries for us to ponder. What a gift.

Happy Thanksgiving.

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