Defining adult bonefish (Albula vulpes) movement corridors around Grand Bahama in the Bahamian Archipelago

Abstract

Development on Grand Bahama in the Bahamian Archipelago during the 1950’s to 1970’s resulted in substantial changes to the island’s geography. Hawksbill Creek, which potentially served as a natural migration route for fish from the north side to the south side of the island, was severed and replaced by a man-made canal called the Grand Lucayan Waterway (GLW). Bonefish (Albula spp.), a sport-fish that contributes more than $141 million to the Bahamian economy annually, is one such species that may have been affected. The purpose of this study was to determine contemporary movement corridors of adult bonefish during their spawning season (October to May) in Grand Bahamian waters. This was accomplished by using a passive acoustic telemetry array of 17 receivers and 30 transmitter-implanted individuals. A total of 26,108 detections were logged from 20 of the fish. Eight bonefish tagged on the north side used the GLW to access waters on the south, whereas no transmitter-implanted fish tagged on the south side fully traversed the man-made canal, suggesting that primary spawning areas may be located on the south side of the island. This result is consistent with previous reports that bonefish spawn near deep water which is easier to access on the south side of Grand Bahama. Further supporting this finding, two other bonefish tagged on the north side forayed around the east end of the island and were detected on receivers approximately 88 km from their tagging locations. Additionally, two other bonefish tagged on the north side were detected at the west end of the island, with one individual continuing its movements along the south side of the island for an approximate straight-line distance of 80 km. Canal use typically corresponded to days immediately prior to or after new or full moons, indicating that movements were related to spawning. This study suggests that despite historical habitat modifications, bonefish today use the GLW as a movement corridor for migrations during spawning season, emphasizing the importance of protecting the canal from any activities that could impede connectivity.