Spatiotemporal Variability of Benthic Communities on Weathervane Scallop Beds off Alaska

<p>Marine benthic communities are critical biotic components of habitat due to their roles in ecosystem function and health and as indicators of ecosystem change. Benthic communities are receiving increasing attention as institutions adopt ecosystem-oriented research approaches. We conducted a multidecadal analysis of benthic communities in areas targeted by a commercial weathervane scallop <i>Patinopecten caurinus</i> fishery on the continental shelf off Alaska. Using bycatch data collected by onboard observers during 1996–2012, we analyzed spatiotemporal patterns in community composition on weathervane scallop beds. We also explored whether spatiotemporal differences were related to environmental (sediment and depth) and anthropogenic (dredging effort) variables. Statistically significant (<i>P</i> < 0.05) temporal changes in community composition occurred during 1996–2012, with a split between 1996 and 1999 and subsequent years. Taxa contributing to temporal changes were not consistent across fishery registration areas. Significant spatial differences in community structure were detected both at the scale of registration areas (200–2,000 km) and individual scallop beds (<50 km). We also found significant correlations between benthic species composition and environmental and anthropogenic variables over space and time. Although the relationships were generally weak, the ecological associations were consistent with expected depth and sediment relationships in this region. Our results are directly relevant to the habitat objective of the scallop fishery management plan, inform essential fish habitat designations for weathervane scallops and other commercially important species, and serve as a baseline against which to compare future changes associated with fishing and climate change. Ensuing research should include the collection of environmental data at the spatial scale of individual scallop beds as well as controlled experiments on the impacts of fishing on benthic communities and their recovery.</p> <p>Received August 19, 2016; accepted August 8, 2017</p

The cooked meat tissue served at the 1951 ECAD.

<p>Division of Vertebrate Zoology, YPM HERR 19475. Courtesy of the Peabody Museum of Natural History, Yale University, New Haven, CT, USA.</p

Explorers Club members discussed in the text.

<p>(A) Arctic explorer Father Bernard Rosecrans Hubbard, Society of Jesuits, University of Santa Clara. (B) Polar explorer Captain George Francis Kosco, United States Navy. (C) Circumnavigator, impresario, and ECAD Committee Chairman Commander Wendell Phillips Dodge. (D) Curator-Director of the Bruce Museum, Paul Griswold Howes. A, C, and D courtesy of The Explorers Club Research Collections. B courtesy of William G. Kosco.</p

List of GenBank accession numbers for specimens used in phylogenetic and pairwise distance analyses.

<p>List of GenBank accession numbers for specimens used in phylogenetic and pairwise distance analyses.</p

Phylogenetic tree of <i>C</i>. <i>mydas</i> and relatives.

<p>Phylogeny based on a 369 bp alignment of the mitochondrial cytochrome-b gene, inferred from Bayesian analyses. Specimens from the Pacific Ocean form a clade (green), whereas those with Atlantic or Mediterranean origins (blue) are unresolved. The YPM specimen is bolded. Node labels indicate posterior probability percentage support estimates. All branch lengths are in substitution units.</p