Southern Resident Killer Whale L112 Stranding Progress Report 1

April 2, 2012 — The Northwest Region Marine Mammal Stranding Network, administered by NOAA Fisheries Protected Resources Division in Seattle, Wash., is investigating the death of a juvenile killer whale that stranded on Washington State’s Long Beach Peninsula on Feb. 11, 2012. The whale was tentatively identified as L-112, based on a comparison of its external markings with a photographic catalogue of known whales. L112 was part of the L4 matriline of L pod of the Southern Resident killer whale population, a species listed as endangered under the Endangered Species Act.

Several organizations belonging to the Stranding Network are participating in the stranding investigation, including Dr. Deborah Duffield, Portland State University; Jessie Huggins, Cascadia Research Collective; Dyanna Lambourn, Washington Department of Fish and Wildlife Marine Mammal Investigations; Amy Traxler, The Whale Museum; Dr. Joe Gaydos, University of California SeaDoc Society; and Dr. Stephen Raverty, Animal Health Center in British Columbia.

Initial Examinations

Portland State University, Washington Department of Fish and Wildlife, and Cascadia Research Collective conducted the post-mortem examination of the whale in the field on Feb. 12, 2012. The team collected morphometric data, photographs and tissues for analysis. Samples were submitted for genetic analysis to confirm the whale’s identification as a Southern Resident. Observations indicate the animal was moderately decomposed, but likely dead for less than a week when found. The investigative team has not yet determined a cause of death for this animal, but examiners found extensive hemorrhage in the soft tissues of the chest, head and right side of the body. Photographs from the examination and a preliminary report of observations by the field team are posted on the Cascadia Research website.

The head was collected, frozen, and scanned at the VCA Veterinary Specialty Center of Seattle. The computed tomography (CT) data collected by the scanner are being analyzed by veterinary radiologists Dr. Tori Mcklveen, VCA, and Dr. Sophie Dennison-Gibby, NOAA Fisheries. After scanning, Dr. Gaydos and Dyanna Lambourn led a team that performed a forensic dissection of the head at the Friday Harbor Laboratory March 6-7, 2012.

The skeletal remains from the field examination were transferred to the Whale Museum for further cleaning and examination. Over a three-day period in mid-February, the flesh adhering to the bones was removed and the bones were secured to racks to be cleaned in sea water. During handling, museum staff examined the bones for any obvious fractures, but none were found.

After soaking, the bones will be further cleaned, dried, and re-examined. Any minor fractures that are found will be documented, photographed, and noted in the final examination report. The Whale Museum has requested authorization from NOAA to retain L-112’s skeleton and skull to be used for exhibit and educational purposes at the museum.

Environmental Conditions

Based on the approximate date of death, NOAA Fisheries and the NOAA Hazardous Materials Response Division reviewed environmental data from early February. They found that prevailing wind and currents between Feb. 1 and Feb. 11 were predominantly from the south. Local current conditions are largely influenced by eddies flowing northward from the mouth of the Columbia River. This indicates that the animal likely died near the Columbia River or to the south, and could have drifted a substantial distance before being cast ashore on Long Beach. Other environmental factors being researched include earthquakes and whether they could cause trauma or disorientation, and sea surface temperature. Diet studies are underway to further investigate winter feeding habits.

Human Activities

We're seeking information from a variety of sources in an attempt to identify whether human activities may have contributed to the injuries we observed. Communication with the U.S. Navy, Canadian Navy, U.S. Coast Guard, U.S. Air Force, and fisheries managers is on-going or being initiated. NOAA Fisheries has reviewed reports received by the Marine Mammal Authorization Program from commercial fishing vessels between January and February 2012, and found that no incidental mortality or injuries involving killer whale(s) were reported anywhere on the West Coast during this period.

Sample Analysis

Cascadia Research Collective is managing distribution of samples, sample data, and the dissemination of results to the investigation team. Parasites, bacteriology, and food habit samples have been sent to several labs for analysis and results are pending. Oregon State University School of Veterinary Medicine and Dr. Raverty will analyze histopathology samples collected during the post mortem examination and head dissection. The results of these analyses, which are likely to take several weeks to compile, will be used to supplement the preliminary findings from the field examinations and compiled into a report, possibly for publication. Submission of contaminant, virology, and biotoxin samples is pending.

Information collected by the Stranding Network and NOAA Fisheries Protected Resources is being shared with the NOAA Fisheries Office for Law Enforcement, which is conducting an independent enforcement investigation of the event. Direct media inquiries for this case to Brian Gorman of NOAA Public Affairs, 206-526-6613. He’ll provide updates as information becomes available.