Early Stages of Eastern Caribbean Cephalopods: Identification, Abundance, and Distribution

This study examined the density, abundance, distribution, and diel vertical migration patterns of paralarval cephalopods in waters surrounding the US and British Virgin Islands. Survival through the paralarval stage is crucial during the short cephalopod life cycle, yet very little is known about spawning location and much less regarding behaviors in the paralarval stage despite significant commercial fishery interest in adult cephalopods. For this study 729 specimens were collected in 2009 during an anomalous freshwater plume using MOCNESS and Bongo nets aboard the NOAA R/V Nancy Foster during the Coral Reef Ecosystem Research Survey. Cephalopods were sorted from plankton samples and identified to the lowest taxonomic group possible. We found highest densities at midwater (~50m) intervals and a diel migration pattern was observed, with paralarvae favoring the 0-25m range at night and 75-100m range during the day. We were able to identify nine distinct species, four additional genera, and two additional families as well as differentiate several specimens that we were unable to identify but have recorded with images. Of these groups, several genera of both squid and octopus dominated the cephalopods sampled in the study range. We tracked specific behavioral patterns in regards to depth interval and diel distribution for the groups that were particularly prevalent and taxa known to have a strong commercial importance. We believe this study is valuable in that we documented a large volume of high resolution images that can serve to facilitate future identifications, as well as having contributed unique species identification and behavioral information for these top predators during this understudied portion of their lifespan. Given the importance of cephalopods to the commercial fishery sector, this study also provides useful information in regards to spawning and larval behavior that can lend itself to advancing fisheries management practices.