JJ was released off Pt. Loma, San Diego, at about 1018 hours on 31 March (Tuesday)
1998. We then tracked her and monitored her behavior electronically and visually
through 2 April (Thursday) using several methods.
Electronic tracking sytems: JJ was equipped with a total of 5 radio-transmitters that were encased in two housings. One housing was attached to her skin surface about 4 feet behind her blowhole. That housing contained one satellite-linked radio transmitter (operating in the ultra high frequency band, or UHF) and one short-range radio transmitter (operating the very high frequency band or VHF). Another saddle shaped housing was attached to her skin surface over the first bump of her dorsal ridge, about 2/3 the way back from her head. That housing contained two satellite-linked radio transmitters and one short-range radio transmitter.
The satellite-linked radio transmitters allowed us to follow her movements and dive behavior remotely using the Argos Data Collection and Location Service to locate her and acquire data. There are two satellites operating in the Argos system, both orbiting the earth over the poles. The characteristics of those orbits resulted in about 5 good opportunities each day for JJ to be located. On each of those 5 orbits, JJ could be detected during a 10 minute window if she was at the surface then. We were able to locate her this way about 2 to 3 hours after a satellite passed over and detected signals from the transmitters.
The short-range VHF transmitters allowed us to track her by boat (the M/V Megalodon), as long as we remained within about one or two miles of her, or from land from a greater distance if the ground crew was on bluffs or peaks along the mainland. During the tracking period we tracked JJ separately by both boat and from land. This tracking allowed us to collect detailed observations on JJs swimming, diving, and feeding behavior. Because signals from the transmitters can only be heard when the transmitter’s antenna breaks the sea surface and because we might detect only one or two of these signals each time JJ surfaced, we used an automatic direction finding (ADF) system to help us navigate and follow her signals. This system consisted of four antennas, mounted at right angles to each other, on the tracking boat on a mast about 30 feet above the sea-surface. The antennae were hooked into a radio receiver, which was tuned into the transmitter’s frequency, and an ADF circuit board that determined which antenna detected the signal best. A series of lights responded to that signal which then told us which direction to turn to stay on JJ’s track.
We also dropped sonabuoys (floating receiver-transmitters with underwater microphones attached, called hydrophones) off the tracking boat to try and triangulate on JJs vocalizations and to record any sounds that she made while travelling or feeding.
To automatically log our own movements on the boat as we searched for or tracked JJ we
used a Global Positioning System (GPS) receiver hooked up to a small laptop computer which
recorded our location accurately every 30 seconds. The GPS system is also based on
satellite telemetry, like the Argos system, but essentially operates in the opposite
way. With Argos tracking, the transmitter is on the surface of the earth (in our
case on JJ) and the receivers listening for signals from a transmitter are located in the
satellites that are orbiting the earth. The location of the transmitter on the
earth’s surface is calculated by processing done by the satellite receiver
system. With GPS, the transmitters are on the orbiting satellites and the receivers
that listen for signals from those transmitters are on the surface of the earth (in our
case, or perhaps in airplanes in other applications). The earth-bound GPS receivers
have the computing abilities to calculate locations in this case.
Post-release monitoring and tracking:
Once JJ was released, she dove immediately under the release boat (U.S. Coast Guard Buoy Tender, Conifer) boat and evidently remained submerged for several minutes. Indeed, she was not sighted again until we located her about 2 hours later several miles to the east. Her disappearance was rather remarkable considering several hundred pairs of eyes looking for her from the release and support boats and helicopters. A similar disappearing act was, however, also observed during release of another gray whale, Gigi, in 1972. Gigi was not resighted until 2 days after release.
We acquired the first satellite fix for JJ a little after 2 P.M. which suggested (it was not a terribly accurate location) that she had been several miles east of the release site, at around 12:30 P.M., near the beach at Coronado (near San Diego Bay). We then terminated our search pattern and headed in that direction under stormy skies and seas and detected a radio signal with our ADF system at around 2:25 P.M. Futher signals allowed us to home in on her and we made visual contact at around 2:45 P.M. At that time she was swimming south at about 2 knots and about 100 yards off the beach, just beyond the surf. We tracked her to the Imperial Beach pier, just north of the U.S.-Mexican border, by 6 P.M. where she lingered for a while. She then headed north for a couple of miles, then south, and then back north to near the rock jetty at the entrance to San Diego Bay where we last saw her visually just before sunset. JJ remained in that area until at least 10 P.M. when we lost radio contact owing to a substantial amount of radio noise coming from the North Island Naval Base, the commercial airport at Lindbergh Field, and a variety of other sources which prevented us from picking JJs transmitter signals out of the substantial background noise. Our ground-based crew had been travelling along the coast from Imperial Beach pier to Pt. Loma and also detected weak signals near the San Diego Bay jetty until late evening.
We had no further satellite fixes to help us find JJ until the next afternoon (Wednesday, 1 April). In the meantime, we made additional searches of the coastline by boat and by land, first south and then north to La Jolla, while awaiting additional satellite fixes. Our search distances were based on estimates of the distance that JJ may have travelled either south (though we were limited in our searches to U.S. territorial waters north of the border with Mexico) or north calculated from her swim speeds that we measured on 31 March. Late Wednesday afternoon we acquired additional satellite fixes suggesting that JJ had perhaps been in the south part of San Diego Bay earlier in the day. We then headed south by boat into the bay while dispatching the ground crew to the Imperial Beach pier. We were unable to relocate her during these searches but we did spot 3 gray whales just outside the entrance to San Diego Bay just around sunset. We made intensive visual and radio observations for several hours at that site to try and determine whether one of those whales might be JJ. None was confirmed to be her.
Early Thursday (2 April) morning we acquired additional satellite fixes from the transmitter in the dorsal ridge, saddle housing which suggested that JJ had been in the area where we were searching the night before. Based on the sensor data and timing pattern of transmissions we suspected, however, that the instruments might have fallen off and might be ashore. Consequently, we did radio surveys along the beach just after sunset and after detecting and homing on some weak signals we were able to retrieve the housing. The toggle attachments appeared to have been set too shallow in JJ’s blubber to hold it fast given the flex in her body near the dorsal ridge when she was swimming.
Our next satellite fix from the remaining transmitter was acquired early Thursday
afternoon and indicated that JJ had been further south near the U.S.-Mexican border just a
few hours earlier. The sensor data and timing of transmissions at that time
indicated that the instrument was still attached to JJ. Consequently we headed
towards that location near the U.S.-Mexican border and when within about 1 mile of the
satellite fix location we began to detect radio signals from the short-range
transmitter. We homed in on that and were able to retrieve the housing from the
beach. We think that it became dislodged from JJ sometime early Thursday afternoon
while JJ was swimming and, perhaps, foraging in that area.
Recent sightings:
We are no longer tracking JJ electronically and so must now rely on opportunistic sightings of her using her unique color patterns and scars to positively identify her. To facilitate that we have provided a small poster of those patterns and scars to the National Marine Fisheries Service which has forwarded them to members of the west coast marine mammal stranding network. Further, we will be distributing copies of those photos to scientists who are actively conducting, as authorized by U.S. federal research permit under the Marine Mammal Protection Act or other national permit in Mexican or British Columbia waters, research on gray whales in the eastern north Pacific.
Since 3 April we have received about 30-40 calls reporting sightings of gray whales,
including small whales, from the Mexican coast near Tijuana northward to Malibu and Santa
Barbara. We have directly investigated as many of those as possible and talked with
the observers of the other sightings. None has been confirmed to be JJ. We expect
that these sightings will continue for a couple more weeks, as there are peak numbers of
gray whales, mostly females with calves or independent calves or yearlings, moving
northward from the breeding lagoons in Baja California. These animals generally may
travel very close to shore and often just barely beyond the surf, similar to our
observations of JJ’s behavior. We will continue to evaluate these
sightings and work with other researchers and wildlife managers to determine if any future
gray whale sightings are in fact JJ. In the meantime, we will continue to be hopeful that
JJ may survive and thrive. In the event that we do have any positive sightings of JJ
we will post them on this web page shortly after confirmation.
More to come later on:
Prepared By:
Brent S. Stewart, Ph.D., J.D. (Hubbs-Sea World Research Institute)
James T. Harvey, Ph.D. (Moss Landing Marine Laboratories)
Pamela K. Yochem, M.S., D.V.M. (Hubbs-Sea World Research Institute)
Ann E. Bowles, Ph.D. (Hubbs-Sea World Research Institute)
Photo Album | Animal Bytes | Main Page | Movies | Updates & News
Visit www.seaworld.com for more information on
Anheuser-Busch Theme Parks
(c) 1997 Sea World, Inc. All Rights Reserved.