Bioacousticians and marine advocates have been closely following plans for the Northern Gateway pipeline in British Columbia, which would greatly increase ship traffic in some coastal waterways that are relatively quiet so far; see previous AEInews coverage.  But another pipeline project, farther along in the permitting process, could push the already stressed waters of southern BC and northern Washington to the acoustic breaking point.  The Trans Mountain Pipeline, built in 1953 and expanded several times since then, is gearing up to nearly triple its capacity and make adaptations that will allow heavy tar sands oil to be moved to the Pacific coast for shipment to Asia.

The expanded Trans Mountain Pipeline would have 75% of the capacity of the proposed Keystone KL pipeline to the Gulf of Mexico, so it has triggered active resistance on similar climate change grounds as Keystone.  At the same time, ocean advocates are stressing the cumulative impact of the additional 720 tanker transits that would occur in already-busy waters that include critical habitats for killer whales, sea lions, and other species.  At this point, most of the additional capacity is targeted for Burnaby, BC (increasing monthly tanker arrivals from 5 to 34), though the pipeline also serves terminals in northern Washington state. (Some of the current capacity is refined and used in North America, but virtually all of the increased capacity will be shipped overseas; thus the tanker traffic will increase 7-fold despite the smaller capacity increase.)

The Canadian Department of Fisheries and Oceans has just released a review of the Trans Mountain proposal, which is currently being considered by the National Energy Board (NEB), and finds it lacking, saying it contains “insufficient information” to adequately assess the threats posed both by underwater noise and ship strikes. “The assessment considers noise from a single project-related ship, without taking into account the additive and cumulative effects of existing noise,” Fisheries and Oceans Canada concludes.

Marine advocates second that concern.  Margot Venton, a staff lawyer with Ecojustice, stresses that “The critical habitat is basically as noisy as it can be. We need to make it quieter.” Misty MacDuffee, a fisheries ecologist with Raincoast Conservation Foundation, said anything that impedes the ability of whales to feed is a serious concern. “It’s just the growing din,” she said. “They are trying to [communicate and hunt] in an increasingly loud environment.” (Thanks to the Globe and Mail for their coverage and all these quotes.)

The NEB review is slated to be concluded by July; the federal government will then take six months to consider the NEB’s recommendation and make a final decision.  If approved, construction could begin in 2016 and be completed the following year.

UPDATE, 7/14/16: The NEB has recommended that the pipeline be approved, despite the likelihood that additional ship traffic will saturate the acoustic environment to the point that ship noise is present in some areas nearly 100% of the time (currently 85%).  Transmountain will need to meet 157 conditions, but they’re confident that will be achievable.  The final stage of the approval process is a final decision from the Canadian government, which is expected by the end of this year.

AEI lay summary of:
Daniel E. Holt, Carol E. Johnston. Traffic noise masks acoustic signals of freshwater stream fish. Biological Conservation 187 (2015) 27-33 (ScienceDirect link)
With each passing year, we learn more about the ways that animals use sound—and so also how human noise interferes with their lives.  A new paper looks at how traffic noise from bridges may impinge on the mating calls of freshwater fish; this is the first study to use some of the new metrics of “communication space” in these important and widespread habitats. The species studied was the blacktail shiner, a member of the largest family of fishes (including carps and minnows), with the study sites being small streams passing under bridges on I-85 in Alabama (image shows one of six sites).

Male shiners make two sounds during mating: loud “knocks” used to challenge other males who are intruding, and softer “growls” used to court females.  Streams are naturally loud environments, with noise from wind, rain, and turbulence; shiners take advantage of a relatively quiet “window” in the broadband noise, between 172 and 366Hz (like many other animals that vocalize in frequency ranges less cluttered by local sounds or other species).  While the traffic noise is not much louder than the natural stream sounds at frequencies above 700Hz, unfortunately for the shiners, in this key quiet window it is significantly louder than the stream noise—and also the seductive growls of male shiners.  The graph shows natural ambient noise (green), road noise (red), and growls (black dotted line).  The two peaks in the growl acoustic spectrum are particularly important; the lower peak in particular is dramatically drowned out by traffic noise.

The bottom line for the fish is that their knocks, which can be heard above the natural sounds of the creek out to about a half meter, are just slightly masked—only within three meters of the bridge are they lost in road noise (3m is the mean; maximum modeled range of effect is 22m).  So these calls of challenge and defense among males, which may also show females who’s the most fit, can serve their purpose unless the action is taking place right under a bridge.  The subtler sounds of the growls, however, are much more impacted.  These sounds, being quieter, are meant to be heard at very close range (generally just a few inches from the nest sites); yet the lower peak in the growl sound spectrum will be effectively inaudible in areas out to 640m (almost a half mile) from a bridge, and the second peak will be similarly masked out to 40m (both distances are means; maximum ranges are, respectively, 12km/7 miles and 1600m/1 mile). Adding insult to injury, peak spawning time is morning, before water temperatures rise, which may coincide with peak morning traffic.  Of course, only a small portion of most spawning streams is near heavily travelled interstates or secondary roads; those near more sporadically-travelled local roads are likely to be less affected.  Still, if the effect extends a half mile or more, large stretches of many streams could have some degradation of their natural and necessary acoustic habitat.

The authors’ conclusion neatly sums up what all this means going forward: