Towed-Diver Surveys,a Method for Mesoscale Spatial Assessment of Benthic Reef Habitat: A Case Study at Midway Atoll in the Hawaiian Archipelago |
| |
Authors: | Jean C. Kenyon Russell E. Brainard Ronald K. Hoeke Frank A. Parrish Casey B. Wilkinson |
| |
Affiliation: | 1. Joint Institute for Marine and Atmospheric Research, University of Hawaii , Honolulu, Hawaii, USA;2. Pacific Islands Fisheries Science Center , NOAA , Honolulu, Hawaii, USA |
| |
Abstract: | An integrated method for benthic habitat assessment is described, in which divers maneuver boards equipped with digital video, temperature, and depth recorders while being towed behind a small boat. The tow path is concurrently recorded by a GPS receiver, and a layback model is applied to more accurately map the data. Percent cover of salient benthic categories is quantified by whole-image analysis of still frames sampled at 30-s intervals. The results of 15 towed-diver surveys at Midway Atoll in the Hawaiian Archipelago during a mass coral bleaching event are presented to exemplify the method and are compared to results derived from conventional methods. Towed-diver surveys bridge a gap between large-scale mapping efforts using satellite data and small-scale, roving diver assessments, providing a mesoscale spatial assessment of reef habitats. The spatial coverage of towed-diver surveys provides comprehensive data to managers concerning the extent, intensity, differential taxonomic response, and bathymetric correlates of bleaching. |
| |
Keywords: | benthic assessment coral bleaching Midway Atoll towed diver |
|
|