Vessel groundings are a major source of disturbance to coral reefs worldwide. Documenting the extent of damage caused by groundings is a crucial first step in the reef restoration process. Here, we describe the application of a novel survey methodology, landscape video mosaics, to assessment of the damage caused by vessel groundings. Video mosaics, created by merging thousands of video frames, combine quantitative and qualitative aspects of damage assessment and provide a georeferenced, landscape, high‐resolution, spatially accurate permanent record of an injury. The scar in a Florida reef impacted by a 49‐foot vessel, imaged in 2005 and 2006, covered an area of 150 m2 (total imaged area was >600 m2). The impacted coral community showed limited signs of coral recovery more than 3 years after the initial impact; the cover of corals was still significantly higher in the undamaged areas compared to the scar. However, seagrass colonization of the scar was observed. Finally, no evidence of further physical impacts was documented even when four hurricanes passed near the grounding site in 2005. The video mosaics developed in this study proved to be ideal tools to survey the grounding scars. Mosaics provide a means to collect information on the size of the damage area and the status and trends of the impacted biological communities and provide a permanent visual record of the damage, thereby expanding the quality and diversity of information that can be collected during field surveys.

Landscape video mosaics (Lirman et al. 2007) were acquired at four sites in the Hind Bank Marine Conservation District, US Virgin Islands (Smith et al.In press), one of which is shown here (Fig. 1). This mosaic covers 31 m 2 with a resolution of 1.8 mm/pixel. Live stony coral cover, estimated from 400 random points on the mosaic, was high (42.5%). The community was dominated by plating or encrusting forms of colonies of the genus Montastraea. Other coral genera identified from the video at lower abundance included Agaricia, Colpophyllia, Helioseris, Mycetophyllia, and Porites.Dive time and diver training were not obstacles to video acquisition for landscape mosaics, which in this case took only 25 min per mosaic by a diver who had only one practice acquisition. Processing each mosaic took about 1 h of analyst time and 24 h of computer time. The ease of data acquisition, ability to use off-the-shelf hardware (i.e., a video camera and possibly lights), and potential suite of indicators (e.g., benthic cover, coral sizes, disease prevalence, and bleaching) that can be obtained from the images suggest that landscape mosaics could be applied widely for surveys of mesophotic coral ecosystems.

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