Abstract

Horseshoe crabs have been around for more than 200 million years and play a role in numerous industries including agriculture, fisheries, pharmaceuticals, and laboratory research.¹ Additionally, horseshoe crabs are often maintained in public display aquaria as both exhibit and education animals. The National Aquarium has housed horseshoe crabs for over two decades and utilizes them for offsite educational outreach programs and touch tank exhibits. Recently a new touch tank exhibit, entitled living seashores (LS), was built. When designing the exhibit, one of the primary goals was to have longevity equal to or better than the longevity in an older system, the children’s discovery cove (CDC) with a goal of minimum two-year survival.

The CDC was once a touch tank exhibit but is currently a holding system for animals used in off-site education programs and there is no public access. During the 15 years that animals were housed in this system there were 63 mortalities. Records were adequate to calculate time in collection and time in the CDC for 48 individuals. The average yearly mortality was 4.2 animals with the greatest number of losses in a given year being 10. The average time in collection was 574.6 days, with a range of 49–1750 days. The average amount of time spent in the CDC prior to death was 392.8 days with a range of 21–1229 days.

The LS exhibit is a touch pool that encouraged visitors to interact with the inhabitants. Since the LS opened in 2015 a total of 5 animals have died. The average yearly mortality has been 2.5 animals. The greatest number of losses in a year was 3. The average time in collection at time of death was 747.6 days with a range of 559–931 days. The average time spent in the LS touch tank prior to death was 552.4 days with a range of 388–672 days.

The goal of having animals in the LS meet or exceed longevity of animals in the CDC does appear to have been met. We are not achieving a two-year survival time (average or for all individuals) once they enter the LS, though average time in the population is over two years. We continue to work to improve survival time for horseshoe crabs.

* Presenting author

Literature Cited

1.  Smith SA, Berkson JM. 2005. Laboratory culture and maintenance of the horseshoe crab (Limulus polyphemus). Lab Animal. 2005;34:27–34.