Localized areas of intense biological activity, or hot spots, in the deep sea are infrequent but important features in an otherwise sparsely occupied habitat (1). Hydrothermal vents, methane cold seeps, and the tops of seamounts are well documented areas where dense communities persist for generations (2–5). Reproductive aggregations where conspecifics concentrate for the purposes of spawning or egg brooding could be thought of as transient hot spots. It is likely that they occur in populations with low densities to maximize mate location and increase reproductive success (6). However, only a few deep-sea reproductive aggregations have ever been documented (7–9), demonstrating the paucity of present-day information regarding reproductive behavior of deep-sea animals. In this paper we describe a unique multispecies reproductive aggregation located on the Gorda Escarpment, California. We document some of the highest fish and octopus densities ever reported in the deep sea, with most individuals of both species brooding eggs. We describe the nesting behavior of the blob sculpin, Psychrolutes phrictus, and the egg-brooding behavior of an octopus, Graneledone sp. observed during annual dives of a remotely operated vehicle (ROV) on the Gorda Escarpment. The animals are concentrated at the crest of the local topography and near cold seeps where they may benefit from enhanced current flow and local productivity. These findings provide new information on the reproductive behaviors of deep-sea animals. More importantly, they highlight how physical and bathymetric heterogeneity in the environment can result in reproductive hot spots, which may be a critical resource for reproductive success in some deep-sea species.
Available at: http://works.bepress.com/shana_goffredi/24/