Dr. Jocelyn Curtis-Quick and her team have been assisting Dr. Heather Masonjones with her ongoing seahorse research in Sweetings Pond. Sweetings Pond on the island of Eleuthera contains a diverse array of species, including both seahorses and octopuses. Originally described in the early 1980’s, this pond has remained unstudied over the past 30 years.The amazing seahorses of the pond (photo credit Shane Gross)

This type of tidal saltwater pond forms in regions with limestone geologic histories, fed from the ocean through cracks and underground caverns. Depending on the size of these connections and how long they have been isolated from gene-flow, these ponds are well known sites of speciation, with an array of endemic or limited-range organisms, and unfortunately, a long list of species declines. The Sweetings Pond site is part of wider assessment of the inland ponds found all over Eleuthera, led by Dr. Jocelyn Curtis-Quick.

All seahorses found are photographes as their marking can be used to identify individuals

Seahorses are marine fish that have captivated humans for generations. Worldwide, their populations are under threat from over-harvesting for curios, traditional medicines and as bycatch from fisheries. They are also declining because of decreasing water quality of their shallow coastal habitats, and increased use of these habitats through poorly-managed tourism. The impacts of these threats are difficult to measure in seahorses, because they are difficult to study in the wild.  The pond species of seahorses, Hippocampus erectus, is also listed as Vulnerable on the IUCN Red List, an international organization dedicated to conservation.

At night a black light shows the tagged fish (photo credit Shane Gross)

Lili Wagner finds a baby octopus on the light trap

The team spent two days assessing the seahorse’s use of different habitats and successfully tagged more than 30 seahorses, enabling the mark and recapture technique to be used to assess population density. In order to assess what the seahorses are eating, as there is little to no research on their prey selection at night, the team set out plankton tows and executed gastric lavage procedures on the seahorses. The stomach contents were preserved and will be sent to a lab at the University of Tampa to be analyzed, and the animals were released unharmed back to the exact location where they were originally found. Because of their monogamous mating system, moving animals from their home location can interrupt mating pairs, and make it difficult for animals to reproduce.

Populations of seahorses are rarely as dense as we have measured in the pond, so from a conservation perspective, this would be an excellent choice of location to protect and conserve for future generations.  Dr. Masonjones presented the preliminary findings at the Bahamas Natural History Conference last week.

If you see seashores in the water around Eleuthera please report your sightings on iSeahorse.