Fertilizer and Animal Feed

The earliest reports of harvesting horseshoe crabs date back to colonial times. Farmers in the 1800s continued the practice of using horseshoe crabs for fertilizer. Records show that in the 1870s, over four million crabs were taken each year. They were harvested from the beaches by hand or from the water with the use of pound nets. The crabs were dried and ground up before they were applied to the fields. Even with this harvesting pressure, the population of horseshoe crabs remained at about 1.5 million from the 1880s through the 1920s. But from then on, the population declined steadily with each decade until the 1960s. Because of the decline in the stock and an increase in the demand for chemical fertilizers, harvesting horseshoe crabs for fertilizer ceased in the 1960s.

Besides its use as fertilizer, some farmers also used horseshoe crabs as a cheap source of food for chickens and hogs. However, the crabs gave the meat a "fishy" taste that required weeks of purging on grain to remove.

Today, horseshoe crabs are once again in demand — this time for biomedical research and the production of LAL, and as bait for the eel and whelk fisheries. Click on the highlighted terms above to learn more about each.