First Observations of Long‐Distance Migration in a Large Skate Species, the Winter Skate: Implications for Population Connectivity, Ecosystem Dynamics, and Management

Abstract

The overexploitation and decline of groundfish populations throughout the 1980s and 1990s resulted in a regime shift on Georges Bank and southern New England, which was characterized by subsequent exponential increases in the observed biomass of Winter Skate Leucoraja ocellata in the region. Recent work suggested that the rate of the Winter Skate biomass increase cannot be fully explained by internal population dynamics of a population without immigration from other regions and/or populations and that adult‐mediated population connectivity (AMPC) with neighboring regions is required to fully explain biomass trends. Despite this, no evidence of long‐distance dispersal has been observed for Winter Skate, with individuals assumed to display high endemicity to specific regions of the continental shelf. Annual movements of 58 Winter Skate captured off coastal New York were examined using passive acoustic telemetry, revealing seasonal long‐distance dispersal capabilities exceeding 1,000 km. In total, 88,783 unique acoustic detections were observed. Telemetered individuals had an average time at liberty of 199.73 d and collectively traveled 17,576.9 km. Individuals tended to migrate south during summer/fall and north during winter/spring. Movement rates of individuals averaged 9.88 km/d (95% confidence interval = 9.25–10.92 km/d) but ranged from 0.13 to 41.38 km/d. An additional 51 recaptured Winter Skate from a total of 3,416 marked with Floy tags suggested greater offshore movement than was observed in acoustically tagged individuals. Our results illustrate that the Winter Skate is a highly mobile species that moves extensively throughout its large geographic range, consistent with its observed ability to rapidly invade neighboring habitat via AMPC. This study has important implications for our understanding of the role of Winter Skate in northwest Atlantic communities and for management strategies therein.

Spatial Connectivity and Drivers of Shark Habitat Use Within a Large Marine Protected Area in the Caribbean, The Bahamas Shark Sanctuary

“…Mature individuals are present in our study regions, although less common than places like a known aggregation site, nicknamed "Tiger Beach, " off The Little Bahama Bank (Hammerschlag et al, 2017). As such, there may be fine-scale genetic underpinnings to these differential migration dynamics, as seen in other elasmobranchs (e.g., winter skate, Frisk et al, 2019), although this remains unknown. Caribbean reef sharks in the present study exhibited high site fidelity to relatively constricted regions of fringing coral reef habitat adjacent to the continental shelf drop off (Tongue of the Ocean in New Providence, Exuma Sound in the Exumas), which supports previous work on this species (Chapman et al, 2005;Shipley et al, 2018).…”

Seasonal and Ontogenetic Variation in Depth Use by a Critically Endangered Benthic Elasmobranch and Its Implications for Spatial Management

“…However, the recent use of electronic tags has provided increased insight into their movement (Siskey et al, 2019). Studies have shown finescale interspecific depth separation (Humphries et al, 2016) and seasonal offshore movements (Hunter et al, 2005), with extensive migrations through coastal waters reported for some species of skate (King and McFarlane, 2010;Farrugia et al, 2016;Frisk et al, 2019). Site fidelity to coastal areas has also been shown in several species (Ellis et al, 2011;Neat et al, 2014;Sousa et al, 2019), including in relation to nursery grounds (Hunter et al, 2006).…”

Separation of realized ecological niche axes among sympatric tilefishes provides insight into potential drivers of co‐occurrence in the NW Atlantic

“…(2019) for Winter Skate Leucoraja ocellate across the NW Atlantic, and the authors attributed those findings to foraging in specified geographic areas, requiring extensive movements. These findings were later supported by passive acoustic telemetry (Frisk et al., 2019). Movement to specific foraging grounds seems unlikely for both L .…”