Using stationary video data to infer relative abundance and distribution of four Seriola species along the southeast United States Atlantic coast

Seriola spp. (i.e., amberjacks) are highly mobile, widespread, and heavily sought-after species in the family Carangidae. Juvenile amberjacks are mostly pelagic and associate with floating items such as Sargassum spp., but adults tend to be more demersal and often associate with natural hardbottom or artificial reefs. We used 9 years (2011-2019) of baited videos (N = 11,691) in a delta-generalized additive modeling framework to elucidate temporal and spatial trends in relative abundance, habitat use patterns, and environmental influences for four amberjack species along the southeast United States Atlantic coast. S. rivoliana was observed most frequently (25.9% of videos examined), followed by S. dumerili (17.9%), S. zonata (4.6%), and S. fasciata (0.5%), but models only explained a modest amount (5-15%) of variability in video counts among species. S. rivoliana relative abundance increased substantially (~450%) over the study period, while the other species displayed no obvious temporal trends. S. zonata was the most inshore and heavily aggregating species, whereas S. fasciata occurred in the deepest water and S. rivoliana was the least aggregating species. Relative abundance of S. rivoliana and S. dumerili was positively related to substrate relief and bottom water temperature, whereas S. zonata displayed a dome-shaped relationship with substrate relief and water temperature and a negative relationship with the amount of hardbottom. Continued video monitoring is needed to assess the potential distributional shifts of amberjacks due to climate change and improve stock assessments of these important reef-associated species.

Automated summary

This study used 9 years of video data to analyze the abundance, habitat use, and environmental influences of amberjacks along the southeast United States Atlantic coast. The study found that the abundance of S. rivoliana increased significantly, S. zonata was the most inshore and heavily aggregating species, and S. fasciata occurred in the deepest water.