A.R. Robinson, P.J. Haley, Jr., P.F.J. Lermusiaux, W.G. Leslie
HARVARD UNIVERSITY
Division of Applied Sciences
Department of Earth and Planetary Sciences
Cambridge, Massachusetts
(617)495-2819
http://www.deas.harvard.edu/~robinson
Accessibility
In late May 1999, Harvard University was contacted by the National Marine
Fisheries Service (NMFS) Department of Compliance in order to help
"back-calculate the drifting trajectory of a
particular dead right whale to determine where it was struck by a ship."
The right whale Staccato had been found dead in Cape Cod Bay on 20 April. It had
last been observed alive off of Provincetown on 15 April. The assumption was
made, barring conflicting information determined from an autopsy, that during
that 5 day time span, Staccato was struck by a ship and fatally injured.
Injuring or causing the death of a whale is a criminal offense and the NMFS
hoped to determine the culprit by attempting to correlate potential strike
locations with the paths of vessels through Cape Cod Bay during the time
in question.
Harvard reseachers rapidly acquired all available data in Massachusetts Bay
from the Massachusetts Water Resources Authority (MWRA) for the months of
March and April 1999 as well as the necessary atmospheric forcing variables
from the Fleet Numerical Meteorological and Oceanography Center (FNMOC).
Using the Harvard Ocean Prediction System (HOPS), the
potential paths of the remains of "virtual whales" were estimated and forecast.
The HOPS model set simulated whales adrift from 800 different sites every
twelve hour for five days -- a total of 8,000 virtual drifters. In real time,
the program took about 8 hours to run.
The important virtual whales are the ones that drifted to the site where the real
whale, Staccato, was observed dead the evening of April 20. The HOPS results
show that if the Staccato died the evening of April 15, she most likely died in
a fairly small patch of water a few miles off Plymouth.
Predicted Possible Strike Locations
The plots below indicate the areas in which a trajectory of a virtual whale
ends within either 5km or 2km of the location at which Staccato was found
dead, given a fatal ship strike at a particular time. The colored ellipses
indicate all locations for which Staccato could have drifted to the location
at which it was disovered. The star is the location at which Staccato was
found dead. The gray circle around it is either 5km or 2km in radius,
depending on the plot. The gray lines show the normal ship paths from the
Cape Cod Canal to Boston or out to the Atlantic.
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| Possible strike locations which end within 5km of death site | Possible strike locations which end within 2km of death site |
The figures below depict the potential predicted drift paths of the whale remains
for the period 15-21 April 1999 if struck and killed at 0700 or 1900 on the date
indicated. The white lines
indicate the paths of the bodies which end close to the final resting place of
Staccato, while the color contours indicate the possible
total distance a whale carcass would travel from any individual model grid point.
Death at 1900 Local Time on 15 April
Death at 0700 Local Time on 16 April
Death at 1900 Local Time on 16 April
Death at 0700 Local Time on 17 April
Death at 1900 Local Time on 17 April
Death at 0700 Local Time on 18 April
Death at 1900 Local Time on 18 April
Death at 0700 Local Time on 19 April
Death at 1900 Local Time on 19 April
Death at 1900 Local Time on 20 April
National Marine Fisheries Service Press Release
The National Marine Fisheries Service prepared this press release to describe the Harvard work.
The Center for Coastal Studies (CCS) described the situation in this manner:
While the cause of death of the right whale called Staccato awaits further laboratory analysis, researchers at the CCS, who discovered the carcass of the 60-ton animal floating in Cape Cod Bay on April 20, today discounted the theory that the whale may have been too ill to avoid the probable collision with a ship that broke its jaw and back.
Based on extensive aerial surveys and zooplankton studies conducted by CCS as part of the Massachusetts Division of Marine Fisheries' right whale management program, Staccato is known to have arrived in Cape Cod Bay in January and engaged in normal feeding behavior up until about a week before her death, according to Dr. Charles "Stormy" Mayo, who directs CCS's habitat studies.
The last known field observations of Staccato alive were made by CCS aircraft and the habitat study team onboard R/V Shearwater on April 15 from 0845 to 1023. "The observations were made south of Provincetown Harbor during an effort to study the relationship between feeding whales and the food resources of Cape Cod Bay," said Mayo. "Staccato approached the research vessel while plankton sampling proceeded. Three observers from CCS concluded at the time that Staccato was behaving normally, apparently foraging for patches of plankton."
An analysis of 26 plankton samples from the area where Staccato was feeding supports the field observations that the whale was in an area of moderate food quality and may have been searching for better feeding areas in the region. These observations suggest that injuries sustained by Staccato occurred after the time of the feeding observation on April 15.
Dr. Moira Brown, who directs the CCS aerial survey program, further noted that Staccato was first seen this season by the CCS vessel R/V Shearwater on January 17, 1999. Seven subsequent sightings of Staccato occurred during aerial and vessel surveys in February, March and into mid-April - (2/1, 3/3, 3/10, 3/14, 3/21, 4/6 4/15). "Throughout the season, her behavior has appeared normal," said Brown.
Staccato was a regular winter and spring
visitor to the waters of Massachusetts and Cape Cod Bays for 25 years from
May of 1974 until the day she was found dead on April 20, 1999. In many
years, her only sighting for that year was in Cape Cod Bay, 70% of all
of her catalogued sightings occurred in Massachusetts waters and she has
been seen here each winter for the last five years. A prolific breeder,
Staccato gave birth to six calves between 1977 and 1997 and brought all
of them to Cape Cod Bay.
HOPS is a flexible, portable and generic system for inter-disciplinary nowcasting, forecasting and simulations. HOPS can rapidly be deployed to any region of the world ocean, including the coastal and deep oceans and across the shelfbreak with open, partially open or closed boundaries. Physical, and acoustical, real time and at sea forecasts have been carried out for more than fifteen years at numerous sites and coupled at sea biological forecasts were initiated in 1997. The present system is applicable in waters from 10m depth to several thousand meters and the heart of the system is a primitive equation physical dynamical model.
This page was last revised at 1115 3 November 2000.