Time-Varying Epipelagic Community Seascapes: Assessing and Predicting Species Composition in the Northeastern Pacific Ocean

Caren Barceló,Elizabeth A Daly,Lorenzo Ciannelli,Craig M Risien,Jameal F Samhouri,Richard D Brodeur,Gonzalo S Saldías

doi:10.3389/fmars.2021.586677

Abstract

The vast spatial extent of the ocean presents a major challenge for monitoring changes in marine biodiversity and connecting those changes to management practices. Remote-sensing offers promise for overcoming this problem in a cost-effective, tractable way, but requires interdisciplinary expertise to identify robust approaches. In this study, we use generalized additive mixed models to evaluate the relationship between an epipelagic fish community in the Northeastern Pacific Ocean and oceanographic predictor variables, quantified in situ as well as via remote-sensing. We demonstrate the utility of using MODIS Rrs555 fields at monthly and interannual timescales to better understand how freshwater input into the Northern California Current region affects higher trophic level biology. These relationships also allow us to identify a gradient in community composition characteristic of warmer, offshore areas and cooler, nearshore areas over the period 2003–2012, and predict community characteristics outside of sampled species data from 2013 to 2015. These spatial maps therefore represent a new, temporally and spatially explicit index of community differences, potentially useful for filling gaps in regional ecosystem status reports and is germane to the broader ecosystem-based fisheries management context.

Highlights

Major initiatives worldwide have recognized the importance of measuring diversity and community structure as indicators of ecosystem condition (Skidmore and Pettorelli, 2015)
The generalized additive mixed effects models (GAMMs) analyses focus on the cold to warm community gradients and how the Columbia River plume affected species communities
The community seascape model (NMDS1∼remote sensing (RS)) results are discussed here, the other model (NMDS1∼In situ (IS)) and their resulting functional relationships with environmental co-variates are presented in the Supplemental Information

Summary

Introduction

Major initiatives worldwide have recognized the importance of measuring diversity and community structure as indicators of ecosystem condition (Skidmore and Pettorelli, 2015). One of the major environmental drivers influencing the coastal ocean off Washington, Oregon, and northern California is the input of freshwater from the Columbia River (e.g., Hickey et al, 2005; Henderikx Freitas et al, 2018) and the small coastal rivers along the coast (Mazzini et al, 2014; Saldías et al, 2020). These freshwater outflows are a significant source of nutrients, sediments, organic matter and other constituents for the coastal ocean (Sigleo and Frick, 2007; Goñi et al, 2013). The use of RS data products related to coastal freshwater input in the study of epipelagic community dynamics is very limited

Methods

Results

Conclusion