Natural history of neustonic animals in the Sargasso Sea: reproduction, predation, and behavior of Glaucus atlanticus, Velella velella, and Janthina spp.

• Published in: Marine Biodiversity
• Main Author: Helm, Rebecca R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Oceanography; North Atlantic
• Online Access: http://dx.doi.org/10.1007/s12526-021-01233-5; https://link.springer.com/content/pdf/10.1007/s12526-021-01233-5.pdf; https://link.springer.com/article/10.1007/s12526-021-01233-5/fulltext.html

Abstract The Sargasso Sea, located in the North Atlantic subtropical gyre, is one of the most well-known ocean surface ecosystems on the planet. It supports numerous ecologically and economically important fish species, juvenile turtles, and endemic species. However, in addition to the floating algae Sargassum from which the sea derives its name, numerous floating neustonic animals also live at the surface, yet their basic natural history remains poorly known. Without the basic knowledge of these species, understanding ecosystem function, food webs, and pollution impacts is impossible. This is especially problematic because pollutants like plastic are now increasing at the surface at alarming rates. This study examines the diet, reproduction, and behavior of four neustonic animal species: Velella velella , Janthina janthina , Janthina pallida , and Glaucus atlanticus . All mollusk species showed unique predatory preferences and behaviors, indicating possible methods of niche partitioning among these species. For example, Glaucus atlanticus showed an equal preference for all prey but preyed primarily by crawling below to consume the underside of prey, while large J. janthina often preyed more on the margin of V. velella and P. physalis , in contrast, J. pallida only preyed on V. velella . Of the four species observed, two reproduced in the lab ( G. atlanticus and V. velella ), and the embryo cases of J. pallida were examined from both collected snails and discarded bubble rafts. High fecundity rates were observed in all species, which may be an adaptation to high loss rates. This study lays the groundwork for future research on neustonic animals in the Sargasso Sea.