The Story of Sooke (L-112)

February 11, 2012: A young killer whale calf washes up dead on a beach near Long Beach, Washington. Further investigation reveals that it is L-112 (Sooke). Sooke was first spotted in January 2009, making her a bit over three years old. She was the second known calf of L-86 (Surprise) and had an older brother, L-106 (Pooka).

February 12, 2012: A detailed external examination and necropsy was undertaken by biologists from Portland State University, Cascadia Research, and Washington Department of Fish and Wildlife (WDFW) Marine Mammal Investigations. The 12’3” (3.75m) female was moderately decomposed and in good overall body condition. Internal exam revealed significant trauma around the head, chest and right side; at this point the cause of these injuries is unknown. Additionally, samples were taken for a variety of analyses: genetics, contaminants, bacteriology, virology, food habits, biotoxins and histopathology. The processing of these tissue samples could take several weeks or months and will hopefully provide insight into the origin of the traumatic injuries or other factors that may have contributed to the death of this whale. Visit Cascadia Research Collective for more information on the initial necropsy.

February 23, 2012: Amy Traxler, Coordinator for the San Juan County Marine Mammal Stranding Network (SJCMMSN), travels down to the VCA Veterinary Specialty Center of Seattle in Lynnwood, WA and meets up with Dyanna Lambourn, marine mammal biologist with WDFW, to get the CT scan performed. The radiology team is able to get some good images of the head, despite the fact that it barely fit through the scan opening in the machine. The results of the CT scan showed no fractured or misaligned bones. There was extensive gas accumulation in the soft tissues and fat, as well as loss of brain matter on the right side. There also appears to be differences in the amount of air and fluid-attenuating material between and around the bulla (ear bones) on the left and right sides. After the scan, Amy transports the skull back to San Juan Island.

Note: One of many theories being explored in Sooke’s death has to do with sonar and navy testing. As there were reports of Naval sonar activity in the Strait of Juan de Fuca the week before the stranding, with documentation of K and L pods in the area as well, the possibility of death by sonar was something the researchers needed to take into consideration.

As such, it was very important that the head remain intact and a CT scan performed. A CT scan can pick up not only images of fractured bones, but also damage to the soft tissues in the head as well as damage and/or abnormalities around the ear bones.

According to Jason Wood, Research Associates at TWM and acoustic expert, sonar and navy training can cause behavioral responses and physical injuries in marine mammals. The strongest link for this is in beaked whales who have been shown to leave an area during sonar activity and are the most common type of cetacean associated with sonar caused strandings. Physical injury from sonar seems to occur via two routes. Necropsies of stranded animals associated with sonar events can show signs of 'acoustic trauma' which involves signs of trauma around the hearing mechanisms and gas filled cavities. This is thought to occur when an animal is exposed to very loud sound waves, which are nothing more than the compression and rarefaction of the medium. As the sound passes through the animal it causes the animal to compress and expand very fast. In areas where there is both tissue and gas, the animal compresses and expands at different rates and extents, such that this difference causes tissues to tear and be damaged thus leading to acoustic trauma. This only happens at very loud levels of sound.

Necropsies of stranded marine mammals associated with sonar events have also shown evidence of gas embolisms, which is hypothesized as the second possible route for sonar induced injury and may be one of the reasons beaked whales are so often associated with these types of strandings since beaked whales are a deep diving group of species. One theory to explain these gas embolisms is that the individual is startled by the sonar during a deep dive, at which point the animal panics and heads fast for the surface. In doing so the thought is that bubbles start forming in the blood and the animal ends up with something akin to decompression sickness seen in human divers.

March 6 and 7, 2012: A detailed dissection of L-112’s head takes place at The Whale Museum’s lab space at the UW Friday Harbor Laboratories. The exam is conducted by Dr. Joe Gaydos (SeaDoc Society and SJCMMSN veterinarian) and Dyanna Lambourn. Several dozen samples were taken during this process which will be sent to various experts for analysis. (All photos below taken by Sandy Buckley.)

Preparing for dissection. Hollow lower jaw. Ear bones.

March 8, 2012: Due to the delicate nature of the skull and the small bones in the pectoral fins, these and few other small bones were brought down to the Burke Museum in Seattle where they are placed in their dermestid beetle colony for cleaning. This process is estimated to take one-two months.

April 9, 2012: Jeff Bradley, Mammalogy Collections Manager at the Burke Museum, sent over these photos. He states, "The bones have been in our beetle colony for 2 weeks now but the progress has just started being visible. I included a few close-ups of the little guys at work." The type of beetles used for this purpose are Dermestes maculatus. Click here to learn more about this species of carrion bettle. (Photo credits: Jeff Bradley)

Whole skull in colony Beetles working on pec fin Beetles working around gum line

April 10, 2012: The bullae were brought back down to the VCA Veterinary Specialty Center of Seattle to get re-scanned at a higher resolution. This was performed primarily for educational purposes as, according to experts, it would not be beneficial diagnostically because it would be hard to differentiate whether any changes seen are due to something ante-mortem or associated with the dissection.

Bullae in formalin jars Scanning bullae individually - wrapped in formalin-soaked paper towels to keep them moist Computer screen during scanning process

April 16, 2012: The last of the samples taken during both necropsy sessions are sent off to the pathologists. Most of the samples went down to Oregon State University, with the remainder going to Dr. Stephen Raverty in Abbottsford, B.C. It is hoped that within a few weeks some of the initial results will start to come in.

April 16, 2012: The bettles are finishing up their work. . . . . more photos from Jeff Bradley at the Burke.

Beetles giving the teeth a good flossing. Pec fin almost done. . . . Pectoral fin complete!

April 29, 2012: Great news from Cascadia Research Collective and The Center for Whale Research! During an off-shore survey conducted by Cascadia, photos were taken of a large group of killer whales. Subsequent identification by The Center for Whale Research showed that L-112's immediate family were amongst the whales photographed that day.

May 2, 2012: After being submerged for ~2.5 months, most of the bones are looking good. Only the caudal penducle area was placed back in the water for further cleaning. The others were pulled out of the water for drying.

Two sets of ribs and the sternum sitting in the sun drying.

May 10, 2012: Members of the Investigative Team looking into the cause of L-112's death met at the NOAA Facility in Seattle to discuss the case. One result of this meeting was the second "Progress Report" which you can view by clicking here.

To be continued as events unfold. . . .

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