Seahorses Shake Up Population Planning
For those of us in zoos who work more with computers than live animals, drama and excitement come in the form of new data challenges. Yes, really. Population biologists love data, and we get a kick out of analyzing new information and coming up with creative strategies to achieve the greater goal of maintaining healthy zoo populations.
Recently, some interesting data challenges came to the Population Management Center (PMC) in the form of the lined seahorse (Hippocampus erectus). This attractive and popular species is held at 49 Association of Zoos and Aquariums facilities around the United States. The studbook keeper and species coordinator of the Lined Seahorse Species Survival Plan® came to Lincoln Park Zoo along with representatives of a few holding institutions to get advice from the PMC on how to keep this population stable and genetically diverse.
Seahorses bring their own unique challenges. Unlike larger animals, such as tigers or polar bears, they aren’t often individually identified and can produce anywhere from 10–800 offspring as often as every two–three weeks. This makes it difficult to even count the number of seahorses in a tank, let alone track the population growth over time at multiple zoos or aquariums. And because male seahorses incubate their mates’ eggs in brood pouches, the identity of the mothers of these offspring may not even be obvious.
All this makes it tough for us to estimate the genetic diversity of the population or determine which seahorses should be prioritized for breeding. But on the positive side, because the seahorse population is comprised of more than 2000 individuals and reproduces fairly easily, only minimal human intervention is needed to help this species remain diverse and stable in zoos and aquariums. We’ll continue planning to optimize the process, but the lined seahorses are doing a good job on their own.
Sarah Long, M.S., is director of the Population Management Center. Hosted at Lincoln Park Zoo in partnership with the Association of Zoos and Aquariums, the Population Management Center promotes sustainable animal populations by advising zoos throughout the country on breeding and transfer plans.