Table of Contents

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

We sampled along two transects in the winters and summers of 2018 and 2019. One transect was off of Trinidad Head, CA and the other Newport, OR (See MOCNESS Towing stations, supplemental files). Each transect consisted of five target stations during the day and at night with replicate tows at each station. However, this sampling design was often modified at sea. This dataset describes daytime samples only.

To sample a range of zooplankton simultaneously, a coupled Multiple Opening and Closing Net Environmental Sensing System (MOCNESS) consisting of a 4m2 net fitted with 1 mm mesh and a 1 m2 net with 333 μm mesh (Guigand et al. 2005) was used. The former is referred to as the Moc4 and the latter the Moc1. The Moc4 and Moc1 each have 5 nets (numbered 0-4) to sample discrete depths. Please see above for depth descriptions. All tows were sent to a target depth of 100 m.

At certain stations we only did oblique tows, these are indicated by ‘oblique’ in the notes section. Additionally, we were not able to sample at every station proposed. Please see the data sheet for sampled stations.

Immediately after MOCNESS retrieval, nets were rinsed with seawater, sieved, and individually preserved in 95% ethanol. Ethanol was changed within 48 h of collection and again within two months to properly preserve larvae. MOCNESS samples were sorted in the laboratory and fish larvae were enumerated and identified to the lowest possible taxonomic level. Fish species of interest (Engraulis mordax and Stenobrachius leucopsarus) were placed in individual vials for further analyses. Individual taxa concentrations (ind 1000 m-3) were calculated by dividing biological counts from each net by the volume of water filtered through the net. Fish larvae of interest were measured for standard length (SL) to the nearest 0.01 mm using a Leica MZ16 dissecting microscope with a QImaging camera and Image Pro Premier 9.1 software.

BCO-DMO Processing Notes:
* Merged Engraulis mordax and Stenobrachius leucopsarus files into 1 dataset

This project will examine the coastal ocean mesozooplankton community and their predation by early life stages of fish in the northern California Current. The goal is to understand how these predator-prey interactions change during different oceanographic regimes that vary seasonally in the region. This study will use a very high-resolution imaging system coupled with net samples to measure trophic interactions within the zooplankton community across a range of environmental parameters (e.g., temperature, relative timing and intensity of upwelling). The camera provides detailed information on the fine-scale abundance and spatial distributions of a wide diversity of plankton, while the net samples will provide biological samples for diet-related analyses. This project will train 12 undergraduate and two graduate students and one post-doctoral scholar. The research team will develop a variety of educational activities and products to facilitate greater outreach to public audiences. Plankton imagery from this project will be used to build the Global Plankton Imagery Library, an open-access repository for plankton imagery that will be a resource for the research community. The researchers will expand the imagery available in the Plankton Portal, a public website they developed in partnership with the Citizen Science Alliance's Zooniverse, that invites citizen scientists to participate in classifying plankton from field photographs. They will collaborate with Science Education specialists to include Plankton Portal kiosks in a new public exhibit at the Oregon State University's Hatfield Marine Science Center (HMSC) Visitor Center, which annually hosts 150,000 visitors of all ages. Importantly, this activity will not only educate K-12 and beyond, but will enable researchers to study what factors motivate citizen scientists, what characterizes "heavy-users", and how those users can be supported and encouraged into advanced collaborator roles. A multi-media artist will join the research cruises as part of the new Artist-At-Sea program. Their artwork will be displayed at the HMSC Visitor Center and University of Oregon's Charleston Marine Life Center and a scaled traveling show will tour Oregon metropolitan areas and underserved communities.

Eastern boundary currents are among the most productive marine ecosystems on the planet and support a significant proportion of global fisheries, yet there are unanswered questions about the role of non-crustacean zooplankton in transferring production through upwelling food webs. This study will answer key questions about the food web dynamics associated with mesozooplankton linkages, sources of carbon production, and consequences for upper trophic levels in different shelf upwelling systems. Not only is there a knowledge gap in how the food web currently functions in transition areas of major eastern boundary current systems, but there is increasing evidence that these systems are changing. Regional and global shifts in major currents, including upwelling strength, together with temperature-induced latitudinal shifts in species ranges that are already occurring and predicted to continue will have major effects on interactions among species, and consequently, food webs. Understanding these interactions and predicting future changes is highly relevant to science, society, and economies. The researchers plan to sample the winter and summer seasons in the northern California Current off central Oregon (intermittent upwelling) and northern California (continuous upwelling) with the high resolution In Situ Ichthyoplankton Imaging System to obtain an accurate description of mesozooplankton communities: their abundances, and horizontal and vertical spatial distributions, over contrasting upwelling/downwelling system dynamics. In parallel, they plan to collect depth-discrete mesozooplankton samples to quantify seasonal diets for larval fishes and gelatinous zooplankton and prey-specific growth rates of larval fishes. Stable isotope analysis of mesozooplankton predators and prey will reveal the relative role of new vs. regenerated production in sustaining food webs such major eastern boundary currents.