Quantification of Habitat and Community Relationships among Nearshore Temperate Fishes Through Analysis of Drop Camera Video

Abstract

AbstractTemperate nearshore reefs along the Pacific coast of North America are highly valuable to commercial and recreational fisheries yet comprise a small fraction of the seabed. Monitoring fisheries resources in this region is difficult; high‐relief structural complexity and adverse sea conditions have led to a paucity of information on temperate reef species assemblage patterns. Reliable, inexpensive tools and methods for monitoring are needed, as many traditional tools are both logistically complicated and expensive, limiting the frequency of their implementation over a large scale. Video drop cameras of varying designs have previously been employed to estimate fish abundance and distribution. We surveyed a nearshore rocky reef off the northern Oregon coast with a video lander (a video camera mounted on a landing platform so it can be dropped to the seafloor) over the spring and winter of 2011. We designed a 272‐point systematic grid to document the species assemblage and the distribution and habitat associations of the reef species, including two overfished rockfishes: Canary Rockfish Sebastes pinniger and Yelloweye Rockfish Sebastes ruberrimus. Species assemblages differed significantly across the reef by depth and by season for the outer part of the reef. Well‐defined habitat associations existed for many species; Canary Rockfish were associated with complex moderate‐relief habitat types such as large boulders and small boulders, while Yelloweye Rockfish were associated with high‐relief habitats like vertical walls. Species associations were evaluated pairwise to identify nearshore complexes. We compared our site with five exploratory reef sites off the central Oregon coast and found that nearshore reefs differed from our site, while offshore reefs were more similar. Video landers provide a solution to the need for increased sampling of temperate reef systems that are subject to difficult conditions and can contribute to habitat mapping, fish abundance indices, and fish assemblage information for monitoring and management of fisheries resources.Received October 18, 2014; accepted January 3, 2015