To describe habitat-specific patterns in the distribution of invertebrates, that provide structure to seafloor communities on the continental shelf off southern California.

The combination of high-resolution seafloor character maps and predictive models of invertebrate distributions will aid managers in identifying habitats of particular concern and areas with vulnerable corals. Our models will be useful for marine spatial planning and ecosystem-based management as well as for assessing the effectiveness of essential fish habitat closures and other marine protected areas.

Presence or absence information for benthic macro-invertebrates, such as deep-sea corals, and associated habitat (i.e., location, sediment type, and depth) were collected within the Santa Barbara Channel off southern California using a towed camera sled. From the surveys, models were developed to predict the probability of occurrence of five commonly observed taxa (cup corals, hydroids, short and tall sea pens, and brittle stars in the sediment). The models were coupled with a seafloor character map of depth and sediment types to produce predictive maps of probability of occurrence of these taxa.

As part of the California Seafloor Mapping Project (CSMP), our team collaborated with USGS and others to create a suite of maps detailing seafloor morphology and geology. Potential benthic habitats have been characterized from high-resolution multibeam sonar data collected along the entire California coast out to 3 nautical miles. We used a towed camera sled to groundtruth these data and to survey biological components of the habitats. Key observations from the video analysis were: (1) occurrence of structure-forming benthic invertebrates (including members of Pennatulacea, Gorgonacea, and Scleractinia, and a variety of sponges), (2) primary habitat types, (3) depth, (4) abiotic and biotic complexity, (5) slope, and (6) biotic coverage. We derived three habitat classes from habitat type and abiotic complexity: soft sediment; smooth, hard mixed rock and sediment; and rugose rock.

From presence/absence data of macro-invertebrates associated with specific sediment types, depth, and location (latitude, longitude), we developed multivariate generalized linear models to predict distribution of various taxa in the Southern California Bight. Coupling these results with spatial information on habitat type and depth (derived from the coastwide sonar data), we created maps of probability of occurrence of these important components of seafloor communities. These distributional maps provide managers, policy makers, and the public with information that can be used in the conservation and management of sustainable marine resources.

The results are published in: Krigsman, L.M., M.M. Yoklavich, E.J. Dick, and G.R. Cochrane (2012) Models and maps: predicting the distribution of corals and other benthic macro-invertebrates in shelf habitats. Ecosphere 3 (article 3):1-16.