Abstract
On Saturday, November 19th, 2011, a 20-m, approximately 70-ton, adult female fin whale (Balaenoptera physalus) was found dead near Point Loma in San Diego in a small cove with no beach access. A high tide four days later permitted access via the sea. Lifeguards secured the animal's tail stock to a boat and towed it 6.5 nautical miles to a public beach at Fiesta Island in Mission Bay for necropsy. Due to waning light, rising tide, and carcass decomposition, only a limited necropsy examination was performed. Evidence of antemortem ship strike was identified based on intramuscular hemorrhage and vertebral fractures along a 3–4 m section of thoracolumbar spine. The following day, the carcass was secured with an interwoven network of ropes. Two days following the necropsy, the animal was towed to a point 11 nautical miles out to sea. It was sunk in the Loma Submarine Canyon at roughly 850 meters using 6,400 kg of steel. Communication and flexibility between several organizations made it possible for the largest whale fall on record to occur smoothly. Organizations involved included the City of San Diego, the US Coast Guard, the San Diego Life Guards, the Southwest Fisheries Science Center, Scripps Institute of Oceanographic Research, SeaWorld, and Virgin Oceanic.
Whale fall production should be considered as a superior form of large whale disposal. A lack of disposal sites has previously hindered on-shore necropsies in right whales. Traditional options for disposal of large whale carcasses include benign neglect with shoreline decomposition, towing out to sea with and without carcass destruction, and burial either at the beach or at a landfill. Limitations to these solutions include availability of equipment and beach accessibility, cost, odor, and massive contributions to landfill materials. Due to the large size of these animals, incineration is not feasible. Whale fall production addresses many of the shortcomings of the standard solutions. Whale fall programs may provide an effective solution for carcass disposal, thus addressing the main factors. In addition to effective carcass disposal, whale falls permit better understanding of ocean carbon cycling and afford the most ecologically sound disposal option for large carcasses. Ongoing studies will monitor the decomposition of the whale and the ecosystems that form.
Acknowledgements
The authors would like to thank Kerri Danil of Southwest Fisheries Science Center, Sarah Wilkin, the Southwest regional stranding coordinator for NOAA, and Dr. Greg Rouse of Scripps Institution of Oceanography, UCSD.