Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

This dataset contains trawl catch composition data from R/V Centennial trawl surveys in the Hood Canal, WA from 2012-2013.  The species name, estimated number, and estimated mass are included for each tow.

Sampling and analytical procedures:

Samples were chosen to target representative aggregations of fish as detected using multi-beam hydroacoustics.  They are not designed to provide quantitative estimates of density, but rather to assess species and size composition and to collect individuals for tissue and stomach sampling.  Net was a Marinovich midwater trawl, deployed using two wires and 2.5 meter FishBuster trawl doors. Trawl was fitted with a 3.2 mm knotless liner in the codend and towed at a vessel speed of 2−3 knots. Vertical opening of the trawl varied between 4.8 and 7.0 m. 

Catch was sorted by taxonomic group, and counted.  Mass of catch was measured using a Marel M1100 series bench scale to nearest 0.1 kg.  In instance of large catch of species, total number was determined by counting a weighed subsample (usueally more than 0.25 of the total catch by weight). 

BCO-DMO Data Manager Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* comma to ;
* apostrophes deleted due to characer restrictions
* NA-> "nd" for "no data"
* blank values in the column indicating the sample was on juvenile changed to "N" for clarity.
 

Description from NSF award abstract:
Low dissolved oxygen (hypoxia) is one of the most pronounced, pervasive, and significant disturbances in marine ecosystems. Yet, our understanding of the ecological impacts of hypoxia on pelagic food webs is incomplete because of our limited knowledge of how organism responses to hypoxia affect critical ecosystem processes. In pelagic food webs, distribution shifts of mesozooplankton and their predators may affect predator-prey overlap and dictate energy flow up food webs. Similarly, hypoxia may induce shifts in zooplankton community composition towards species that impede energy flow to planktivorous fish. However, compensatory responses by species and communities might negate these effects, maintaining trophic coupling and sustaining productivity of upper trophic level species. The PIs propose to answer the question "Does hypoxia affect energy flow from mesozooplankton to pelagic fish?" They approach this question with a nested framework of hypotheses that considers two sets of processes alternatively responsible for either changes or maintenance of pelagic ecosystem energy flows. They will conduct their study in the Hood Canal, WA. Unlike most hypoxia-impacted estuaries, hypoxic regions of Hood Canal are in close proximity to sites that are not affected. This makes it logistically easier to conduct a comparative study and reduces the number of potential confounding factors when comparing areas that are far apart.

Improved understanding of how hypoxia impacts marine ecosystems will benefit the practical application of ecosystem-based management (EBM) in coastal and estuarine ecosystems. Effective application of EBM requires that the impacts of human activities are well understood and that ecological effects can be tracked using indicators. This project will contribute to both of these needs. The PIs will share their findings on local and national levels with Federal, State, Tribal, and County biologists. To increase exposure of science to underrepresented groups, the PIs also will provide Native American youth with opportunities to participate in field collections and laboratory processing through summer internships. The PIs will collaborate with the NSF-funded Pacific Northwest Louis Stokes Alliance for Minority Participation and tribes from the Hood Canal region to recruit and mentor students for potential careers in marine science. This project will support several undergraduate researchers, two Ph.D. students, a post-doc, and two early-career scientists.