“The answer to the threat of man-eating sharks, the scavengers which infest all tropical waters of the world, was announced here today…” (quote from draft OSS/ERE Press Release on the development of a shark repellent; April 13, 1943)

It was the height of World War II and reports of shark attacks consumed the media. At least twenty US Naval officers had been attacked by sharks since the start of the war, raising alarm amongst sailors and airmen who increasingly found themselves conducting dangerous missions over shark-infested waters. To boost morale, the Joint Chiefs of Staff requested the Office of Strategic Services (OSS, CIA’s predecessor) to lead the hunt to find a shark repellent.

Julia McWilliams (better known by her married name, Julia Child) joined the newly-created OSS in 1942 in search of adventure. This was years before she became the culinary icon of French cuisine that she is known for today. In fact, at this time, Julia was self-admittedly a disaster in the kitchen. Perhaps all the more fitting that she soon found herself helping to develop a recipe that even a shark would refuse to eat.

Searching for Shark Repellent:

The search for a shark repellent began in July 1942, just a month after the OSS was formed. The Emergency Rescue Equipment (ERE) coordinating committee was created to keep the Armed Services and various government agencies from duplicating efforts when developing equipment to help rescue military members from dangerous situations.

Housed within the OSS until late 1943, the ERE Special Projects division was headed by Captain Harold J. Coolidge, a scientist from the Harvard Museum of Comparative Zoology, and Dr. Henry Field, Curator of the Field Museum of Natural History. Both men were avid explorers, having led expeditions into arctic, desert, and tropical regions. Coolidge had previously organized and accompanied the well-known Kelly-Roosevelt expedition to Indo-China and had a strong working-knowledge about the necessary equipment for survival in the arctic, while Field had led several anthropological expeditions into the deserts of the Middle East.

Coolidge and Field sent a memo to OSS Director General “Wild Bill” Donovan and the Joint Chiefs of Staff, proposing a plan for “unifying and coordinating the work of different agencies in the field of rescue.” Thus the ERE was born, and one of its several projects was the development of shark repellent.

Julia Child worked for Coolidge for a year in 1943 as an Executive Assistant.

“I must say we had lots of fun,” Julia told fellow OSS Officer, Betty McIntosh, during an interview for Betty’s book on OSS women, Sisterhood of Spies. “We designed rescue kits and other agent paraphernalia. I understand the shark repellent we developed is being used today for downed space equipment—strapped around it so the sharks won’t attack when it lands in the ocean.”

Shark Repellent Found:

After trying over 100 different substances—including common poisons—the researchers found several promising possibilities: extracts from decayed shark meat, organic acids, and several copper salts, including copper sulphate and copper acetate. After a year of field tests, the most effective repellent was copper acetate.

According to several memos from mid-to-late 1943, bait tests showed copper acetate to be over 60% effective in deterring shark bites. Other field tests showed even more promising results. Unfortunately, the copper acetate was deemed completely ineffective in deterring attacks from the other carnivorous fish of concern to the Armed Forces: barracudas and piranhas.

To create the repellent, copper acetate was mixed with black dye, which was then formed into a little disk-shaped “cake” that smelled like a dead shark when released into the water. These cakes could be stored in small 3-inch boxes with metal screens that allowed the repellent to be spread either manually or automatically when submerged in water. The box could be attached to a life jacket or belt, or strapped to a person’s leg or arm, and was said to keep sharks away for 6 to 7 hours.

Skepticism, Shark Chaser, and Shark-toons:

Despite the promising results of initial field tests, the Navy remained skeptical. In December 1943, Chief of the Bureau of Aeronautics Edward Howell sent a memo to the Navy Research Department stating that although “slight repellence was shown in bait tests” with small sharks, it was the Bureau’s opinion “that it is illogical to expect that such effect as was shown in normal feeding behavior would give any promise of affecting the voracious behavior of the few species known to have attacked man.” Even Coolidge himself noted in personal correspondence to one of the lead investigators/scientists on the project, Douglas Burden, in May 1943 that “…none of us expected that the chemical would really function when the animals were stirred up in a mob behavior pattern.”

Nevertheless, the existence of the repellent was soon picked up by the media, and word spread among the various branches of the Armed Forces. Requests for the repellent came pouring in from the Army and Coast Guard. Even if the repellent wasn’t guaranteed to drive sharks away, it would at least provide possible deterrence against bites and have a huge effect on seamen and pilot morale.

The Navy did end up issuing the shark repellent based on the original OSS recipe—also known as “Shark Chaser”—until the 1970s, and it was rumored, as Julia told Betty, that the repellent was even used to protect NASA space equipment when it landed in the ocean. This part of the story, however, is difficult to confirm with documentary evidence.

The Navy didn’t stop with shark repellent. Shark attacks, although extremely frightening, were relatively rare occurrences. To help dispel the myths surrounding shark attacks, the Naval Aviation Training Division in March 1944 issued a training guide based on the ERE research into sharks. Called, “Shark Sense,” the guide was filled with facts about sharks, advice on how to handle yourself when stranded in shark infested waters, and of course, cartoons.

* The entire collection of records related to the OSS and ERE shark repellent program, as well as Julia Child's OSS service, are available at the US National Archives and Records Administration.