The island of Eleuthera, Bahamas contains an unusual population of seahorses in Sweetings Pond, possessing a range of morphological characteristics that overlap between two species of seahorses found in the region, the slender seahorse (Hippocampus reidi) and the lined seahorse (Hippocampus erectus). Our earlier research established that Sweetings Pond seahorses significantly differ in shape and size from either of their potential parent populations, but genetically are H. erectus (Rose, Masonjones, Jones, 2016). To continue our analysis of the possible sub speciation of this population, we investigated further nocturnal behavioral and population attributes. This was accomplished through transects to quantify their population density, and observations and reference measurements of potential predators. Quantifying these aspects at day versus at night has never been reported before, allowing us to provide potentially taxonomically altering data.
Results/Conclusions
Seahorses were observed engaging in non-cryptic behaviors at night, including congregating in large social groups, and perching on the top of vegetation. This is very different to the behavior observed in the daytime, which was comprised of much smaller congregations and, sitting lower on holdfast vegetation. These unusual actions could be attributed to the lifestyle and size of octopus (Octopus brierus) and spider crabs (Mithrax spinosissimus), both potential predators active at night (Harasti et al., 2014). Considering H. erectus is listed on the IUCN Red List as Vulnerable, the identification of these pond seahorses as a unique subpopulation of H. erectus has crucial conservation implications.