Whale Stranding-Save LBI calls for immediate cessation of offshore wind vessel surveys
Whale Stranding-Save LBI calls for immediate cessation of offshore wind
vessel surveys.
In a recent month, six endangered whales beached with no evident cause of death,
and there have been an unusual number of close-to-shore sightings.
There are a number of wind energy companies doing vessel surveys off the New
Jersey/New York coasts using high intensity noise devices to characterize the
seabed for future placement of wind turbines. In many cases the vessels are
traversing the same areas collecting similar data.
Save LBI commented extensively and repeatedly (1) a year ago to the National
Marine Fisheries Service (NMFS) that the noise impact from these devices was
being seriously underestimated, and that it could drive whales towards shore
seeking relief, the specifics on that below.
The beached whales bear no sign of vessel strike or fishing gear entanglement,
leaving natural causes or noise as the potential causes, and raising the likelihood
that our concerns were well-founded.
We recently asked the New Jersey Department of Environmental protection (DEP)
and the NMFS to simply investigate whether these vessels were in the same vicinity
at the same time as these unusual occurrences, but have received no response.
We now call upon the Interior Department to immediately cease the vessel survey
activity until those investigations are done. The Outer Continental Shelf Lands Act
requires suspension of any lease activity if there is a threat of serious, irreparable
or immediate harm or damage to aquatic life.
Improper Noise Estimates.
The NMFS survey approvals were flawed because they underestimated the noise
source level of the controlling Dura-Spark 240 unit, by using a smaller surrogate
device to obtain a decibel (dB) source number.
In addition, the NMFS accepted a noise dissipation rate of 20 dB for every tenfold
increase in distance, but such “spherical” spreading only occurs in the proximity of
the vessel at distances comparable to the water depth. Beyond that, the noise
spreads out in a “cylindrical” manner constrained by the seabed and the sea surface
with noise dissipation closer to 15 dB, which the NMFS itself has used elsewhere.
Taking the low noise source level and high dissipation rate together, the magnitude
and extent of noise disruption to the whales is significantly underestimated. The
NMFS estimated that noise levels above the 160 dB criteria would only exist 0.1
miles from the vessel. Using a proper noise source level and dissipation rate, that
distance extends to 1.6 miles. Since the vessels come close to shore that noise
could drive the whales toward the beach.
Such a large elevated noise range, with the vessel making passes less than 0.1
miles apart, also results in repeated exposures to marine mammals to those
elevated levels.
Common Sense Recommendations-Rejected
Save LBI recommended that a data sharing program be instituted so many
companies would not survey the same area and cause repeated noise exposures.
That was rejected.
Save LBI recommended, with respect to the north Atlantic right whale, that the
vessels survey areas away from the whale’s primary migration corridor during its
migration period. That was rejected as being inconvenient to the applicant to
schedule.
Conclusions
The noise from the offshore wind vessel surveys is a potential cause of the recent
whale stranding and increased near shore sightings. The NMFS and the NJ DEP
should investigate the cause of death and whether these survey vessels were in the
same vicinity at the same time as those events, and make public those results.
Until that study is done and confirms otherwise, the Interior Department must
suspend the vessel surveys.