Digital video aerial surveys of seabirds and marine megafauna in the Gulf of Maine from May 2023 to January 2024

Original provider:
Biodiversity Research Institute

Dataset credits:
Biodiversity Research Institute
HiDef Aerial Surveying Limited
Bureau of Ocean Energy Management (BOEM)

Abstract:
In April 2023, the Biodiversity Research Institute (BRI) commissioned HiDef
Aerial Surveying Limited (HiDef) to conduct high-resolution digital video
aerial surveys in the Gulf of Maine. The surveys aimed to record marine
megafauna, seabirds, and human activity. The designated survey area is
approximately 5 km off the coast of Maine

A total of four surveys were conducted between May 2023 and January
2024. HiDef designed the survey using 2.5 km- and 5 km-spaced transects
across the Gulf of Maine survey area, covering approximately 6,673 km².

Surveys were undertaken using an aircraft equipped with four HiDef
cameras with a sensor package designed and calibrated to achieve a
resolution of 1.5cm Ground Sample Distance (GSD). Each camera sampled
a strip of ~ 104m width, separated from the next camera by ~ 17m, to
provide a combined sampled width of 416m within a 467m overall strip. All
four cameras were analyzed, achieving approximately 10% coverage of the
survey area during each flight.

Data analysis followed a two-stage process in which video footage was
reviewed (with a 20% random sample used for audit) and detected objects
were identified to species or species group level (again with 20% selected
at random for audit). The audit of both stages requires 90% agreement to
be achieved.

The surveys recorded a total of 7,248 birds of 33 species and 534 non-avian
animals of 12 species, in addition to two dead birds. A further 409 birds and
58 non-avian animals were recorded which were not assigned to a species.
An identification rate to species level of 94% was achieved throughout the
survey period.