Assess/monitor effects of MPA status on reef fish populations and spawning aggregations in the Tortugas Ecological Reserves

, South Reserve: Once in the field, the boat captain navigates to previously selected station locations using a vessel-mounted GPS unit. On-site, divers are deployed on the exact station GPS numbers and maintain contact with each other throughout the entire census. One diver is responsible for collecting data on the fish communities utilizing the belt-transect visual census technique over an area of 30m length X limit of visibility width. The belt-transect diver obtains a random compass heading from his data sheet upon arrival at the bottom, swims that heading for a random number of fin kicks written on his pre-printed data sheet, and then swims out his 30 m transect tape along a second random compass heading course, identifying and counting all snappers, groupers, and other major predator species he sees to the limit of visibility. Visibility is measured as the tape is reeled in so that a density calculation can be made later. Once the transect is finished and the diver is back at his starting point, he consults his data sheet for the next random compass heading and random number of fin kicks for the next transect and repeats the process. Up to four transects can be done at each station, depending on time and air supply. Visibility at each site must be sufficient to allow for identification of fish at a minimum of 3m away or the transect counts will be aborted. The second diver accompanies the primary counter, staying behind and off to the side of him, so as not to disturb the count. He may be tasked to do other data collection, such as species diversity, gross habitat characterizations, etc.

North Reserve: Once in the field, the boat captain navigates to previously selected station locations using a vessel-mounted GPS unit. On-site, divers are deployed on the exact station GPS numbers and maintain contact with each other throughout the entire census. One diver is responsible for collecting data on the fish communities utilizing the belt-transect visual census technique over an area of 30m length X limit of visibility width. North Reserve habitat is configured differently, in a more spur and groove style of reef alignment, and thus the transects are conducted differently from the way they are in the South Reserve. Upon arrival on the bottom, divers swim to the ledge-sand interface. The data collector will swim one transect to the left (270 degrees while facing the reef), the next transect to the right (90 degrees while facing the reef), one transect to the diagonal left up the reef slope (315 degrees) and one transect to the diagonal right up the reef slope (45 degrees). All other data collection strategies employed in the South Reserve dives are used here. The habitat is never altered in any manner by lifting or moving structure, as the observer is recording only fish he sees out in the open. The diver is instructed to look forward toward to the end of the transect and to his sides, but not behind him. On-site, no attempt to avoid structural features within a habitat such as a sand patch, coral head, an anchor or a derelict fish trap should be made as these features affect fish communities and are "real" component of the habitats. The only instances when the transect should deviate from the designated path is to stay above 130 ft (limitations imposed by diving). The typical transect should take only about 5 minutes regardless of habitat type or number of animals present, as we are counting only the larger more visible species.