An ongoing challenge for ocean regulators has been our relatively coarse understanding of where ocean animals are at any given time.  For many species, we’ve been limited to relatively broad-brush data, such as regional population estimates or having a moderately clear idea about particular feeding or breedings areas, with limited knowledge of where these same animals go at other times of year.  All this has made the crucial task of estimating the impacts of human activities (Naval sonar and explosives exercises, oil and gas seismic surveys, construction of new shipping ports) somewhere between difficult and impossible—leading to a mountain of EISs, agency determinations, and court filings over the question of how best to protect ocean life from our noisy actions at sea. Confounding matters for all concerned, on the matter of protecting key habitat, the Navy has sometimes prevailed and sometimes lost in recent challenges.

Over the past decade or so, several projects have been bringing data together from a slew of historical studies, along with doing new surveys in the field that flesh out our understanding of animal distributions.  These efforts are beginning to bear fruit.

This week, a team from Duke University’s Marine Geospatial Lab released a series of maps and new mapping tools to the public and to other researchers, making available data they’ve been compiling for use in the current round of environmental analysis for the Navy’s east coast and Gulf of Mexico training ranges, and for inclusion in NOAA’s ongoing Cetacean and Sound Mapping project (also known as CetSound).

In addition to an open-access paper published in Nature Scientific Reports, a set of comprehensive species-specific supplemental reports (each one running to over a hundred pages), and a good layman’s overview using the Story Map platform, the Lab also has an online mapping portal, OBIS-SEAMAP, that displays annual animal densities for marine mammals, seabirds, sharks, rays, turtles, and even a few lizards of conservation concern.  OBIS-SEAMAP—short for the Ocean Biogeographic Information System: Spatial Ecological Analysis of Megavertebrate Populations—archives hundreds of surveys, satellite telemetry datasets, and photo-ID collections, and has now expanded to include long-term archival of species distribution models. Read the rest of this entry »

A team of researchers from Oregon State University has made the first-ever recordings of what the soundscape is like in the ocean’s deepest spot: the Challenger Deep.  This part of the Mariana Trench is more than 36,000 feet below the surface, but it’s not all that isolated from the normal cacophony of the seas.  As lead investigator Robert Dziak says,

“You would think that the deepest part of the ocean would be one of the quietest places on Earth. Yet there is almost constant noise. The ambient sound field is dominated by the sound of earthquakes, both near and far, as well as distinct moans of baleen whales, and the clamor of a category 4 typhoon that just happened to pass overhead.”

They also heard large ships coming in “loud and strong,” and even the calls of a smaller  toothed whale or dolphin relatively near the surface; you can listen to short sound clips here.  It may seem surprising that sound penetrates so deep.  But of course, seven miles is not really all that far in the ocean; whales routinely communicate over larger distances, and several human sounds sources are readily heard for tens of miles around (or hundreds when caught in a sound-reflecting layer).  What sets the ocean’s depths apart is the extreme density of the water, which can facilitate sound transmission.  Still, it’s a bit disconcerting to realize that no part of the sea is truly free of the acoustic footprints of man.