During the fall of 2006, scientific divers from UGA and Gray's Reef were conducting a reconnaissance dive at JY Reef, a Pleistocene shell bed mostly comprised of large, coldwater scallops (placopectin magellianicus) that once thrived offshore Georgia between 30,000 and 40,000 years before present (ybp). The JY area is located approximately 18 km north of Gray's Reef National Marine Sanctuary and is also a very active live-bottom community. Scientists who do research in Gray's Reef frequently visit JY Reef to compare and contrast growth rates of the invertebrate communities that inhabit both areas.
During this dive, a large subfossil bone was discovered partially embedded in the reef. On subsequent dives, loose sand was removed from around the bone revealing a long, slightly curving bone mostly embedded in the compacted silt and shell. The bone continued further into the reef bed. A cross-sectional view of the now partially exposed bone caused researchers to suspect it was that of a baleen whale.
During the initial investigation of the bone, a small section was recovered. This bone fragment was carbon dated at UGA's Center for Applied Isotope Studies and determined to be approximately 36,000 years old. This date fit well with the dates already determined for the shell bed (30,000 to 40,000 years before present) and also documented that the bone had been buried relatively quickly after the whale's death.
At the time of the whale's death, JY reef was most likely near shore and shallow. The Georgia coastline has fluctuated considerably over time due to climate change. Evidence of the thriving community of coldwater scallops that were present when this whale lived indicates that Georgia waters were colder at the time of the whale's death. During the colder climates, more of the Atlantic Ocean's water was taken up in ice effectively moving the coastline further out. However, since only a few remains of the whale have been discovered to date, it cannot be determined if the whale died and sank at JY reef or was washed into shallow waters and beached.
Since the bone was determined to be much larger than originally thought; not readily recoverable; and would require extensive excavation, a bottom disturbing permit was required. After approximately one year of discussions with multiple state and federal agencies, the United States Army Corps of Engineers issued a permit for excavation.
Excavation began in the summer of 2008 and involved cutting through fossilized shell beds before reaching softer, but hard packed silt. Divers worked diligently with hammers, chisels and knives to cut away the overburden and carefully removed the sediment immediately around the bone.
While digging, visibility was often reduced to zero. Divers had to stop working briefly to allow the currents to carry the silt laden water away before viewing their progress. After numerous dives, the entire bone was exposed and measured approximately 1.5 m in length. The bone was clearly fractured in many locations making an intact recovery unlikely.
Since the diving was typically limited to three dives per day and approximately 30 minutes per dive, it was decided that the best tactic was to recover the bone in sections. The bone sections were carefully lifted from the resting place in the reef, bagged and sent to the surface for recovery. Each bone section was packaged upon recovery and readied for the trip back to the dock and then to Athens, GA. At this time, it was clear that this was a baleen whale mandible, but until conservation processes were completed a positive identification could not be provided.
Conserving the Bone
Once the initial cleaning was completed, the bone fragments were sent to Emory University's Michael C. Carlos Museum in Atlanta, GA. Students from both Emory University and UGA participated in the conservation of the whale mandible. Work continued on the whale mandible throughout the spring and summer 2009 semesters giving students valuable hands on experience with curation methods.
A Connection Between Past and Present
The bone has been identified by scientists at the Smithsonian National Museum of Natural History (SNMNH)as a left mandible from an Atlantic gray whale, a species that is now considered extinct. The Atlantic gray whale was last documented by whalers in the early 1700s. The gray whale was highly sought by the whalers due to their high oil yield and common occurrence to coastal waters making them both profitable and readily available to local whaling vessels. It is unknown, but highly likely that the pressure from whaling was the driving force that pushed the Atlantic gray whale to extinction.
From the beginning, a major goal of this project was to help educate the public about the gray whales that once roamed the Atlantic ocean. To assist with this goal, SNMNH offered to make a mold of the original whale mandible and produce quality casts for display and research. The gray whale mandible was delivered to SNMNH in Washington, D.C. in December 2009 and the following year resided in the fossil lab during the mold fabrication. The fossil lab has large glass windows allowing the visitors to the museum to view projects as they take place.
The silicon mold can be used for making multiple casts and replicates even minute details from the original bone. The SNMNH produced five resin casts with this mold of which one will remain at the SNMNH and the rest will be on display on the UGA campus, Athens, GA; UGA Marine Extension on Skidaway Island, Savannah, GA; and the Georgia Aquarium, Atlanta, GA. The SNMNH will retain one cast for their research efforts on the now extinct Atlantic gray whales.
Following the cast making process, the whale mandible was returned to Athens in late 2010. The next step to get the casts ready for display was to paint them to resemble the original. The Scientific Illustration group at UGA's Lamar Dodd School of Art and Design was contacted and readily agreed to take on the challenge. Amy Sands, a senior working towards a degree in Scientific Illustration agreed to paint one of the casts as part of her senior thesis (Figure 12). As part of her degree, Amy had to develop techniques to bring out the weathered features of the original whale mandible in the cast. In addition to painting the cast, Amy also produced a poster displaying her work on the whale project and submitted a senior thesis (1.62 mb) to the school.
Faculty, staff, students and volunteers from the University of Georgia, Georgia Institute of Technology, Emory University, Georgia Southern University, NOAA's Grays Reef National Marine Sanctuary, Georgia Aquarium, Inc. and the Smithsonian National Museum of Natural History have donated hundreds of hours to make this paleontological project a success. It is hoped that through the efforts of this project, the public will be made aware of the magnificent animal that once roamed Georgia's waters. It is too late to protect the Atlantic gray whale, but others including the right whale are still on the edge of extinction.
GRNMS has teamed up with The University of Georgia to sponsor a gray whale display at the UGA Marine Extension Aquarium located on Skidaway Island, Savannah, Georgia. The display will showcase one of the mandible casts that had been painted by UGA's Scientific Illustration students and faculty. Also included in the display will be a poster giving a brief history of the gray whale and its discovery offshore Georgia.