Research Technical Report

Evaluation of sub-surface research platforms for quantifying seafloor habitat recovery: implications for monitoring and management

McPeek, A. and L. Minnis (December 2007)

A Capstone Project. California State University, Monterey Bay.

ABSTRACT

Mobile-bottom contact fishing gear can dramatically alter seafloor habitats and associated epifaunal invertebrates, which are important habitat for fish species. This project focuses on the recovery rates of seafloor habitats and associated epifauna by looking at videographic data that were collected using Remotely Operated Vehicles and towed camera sleds. The goal was to compare the utility of an ROV and a towed camera sled for quantifying the recovery of seafloor habitats. To accomplish this, we asked the question: which technology, ROV or towed camera sled, is superior for quantifying the recovery of seafloor habitats in naturally occurring low-relief topographic environments? Videographic data were collected on two cruises in June 2006 and June 2007 through the use of an ROV and a towed camera sled. A total of 14 videographic transects were analyzed, ten ROV and four towed camera sled. For each video transect we counted mounds and depressions using two size categories 10 to 20 centimeters in diameter, and greater than 21 centimeters in diameter. The total number of frames per transect were also calculated. Data were categorized into six groups: small mounds, large mounds, total mounds, small depressions, large depressions, and total depressions. The data were transformed in order to perform statistical analysis in R. A one-way; two tailed ANOVA, as well as, a Kruskal-Wallis determined that there was no significant difference between the ROV and the towed camera sled. These results, that the ROV and the towed camera sled are comparable technologies, can be utilized in future draft management plans.