Presence -absense data of macro benthic invertebrates within the Santa Barbara Channel, California

Data was collected from within the Santa Barbara Channel from Refugio State Beach to Hueneme Canyon. Visual surveys of the seafloor were conducted 29 September to 8 October 2008 and 10 to 20 August 2009 using a camera sled towed from the R/V Shearwater. The camera sled was towed one meter above the seafloor at approximately one knot along transects roughly one nautical mile in length. Ten second observations were made on benthic macro-organisms to lowest possible taxa, primary (>50% coverage within the viewed area during the 10-second sample) and secondary (>20% coverage within the viewed area during the 10-second sample) substratum type (e.g., rock, sand, etc.), and abiotic complexity (measured as low, medium, and high) based on small-scale variations in height of the seafloor surface. Numeric habitat classes of 1, 2, or 3 was assigned to each 10-second sample by combining observations of primary and secondary substrata with abiotic complexity. We developed generalized linear models (GLMs) to predict the probability of occurrence for the most frequently observed macro-invertebrate taxa. Presence-absence data from the 10-second samples were fit to binomial GLMs with logit link functions (multiple logistic regression) using alternative combinations of three covariates (block, also known as location, depth, and habitat class) and all possible 2-way interaction terms. Models were validated and using a program called MGET maps were created showing predicted probabilities of occurrence within the Santa Barbara Channel.