Cross-platform Ecosystem Assessment Through Characterization of Prey
Habitat Suitability and Predator Occurrence off Newport, Oregon
Abstract
The coastal waters off Newport, Oregon are part of a naturally dynamic
ecosystem influenced by the California Current. In additional to highly
variable interannual and decadal processes, recent environmental
monitoring has indicated instances of persistent warm water masses in
the region. One method of assessing long standing shifts in the ecology
of this coastal and offshore environment is to associate physical
oceanographic variables with the presence of indicator species such as
marine mammals. Using cross-platform oceanographic and spatial data
sources, we evaluated prey habitat suitability and marine mammal
distribution across three years. The Ocean Observatories Initiative
(OOI) maintains a series of coastal and offshore monitoring platforms
and data systems that include cabled sensors and gliders. Since 2016,
this conglomeration of resources has continuously collected information
such as temperature, dissolved oxygen, pH, pCO2, chlorophyll and nitrate
from the continental shelf near Newport out to the Axial Seamount along
the Juan de Fuca Ridge. Gliders travel along five east-west transect
lines from a depth of 0-1,000 m, contributing greater spatial resolution
of these variables. Approximately 10 species of marine mammals inhabit
the waters off Oregon, several of which feed within the region of
interest. To obtain marine mammal distribution data within a 1,000 km2
area surrounding the OOI cabled and glider instruments, we queried the
Ocean Biogeographic Information System (OBIS) database for observations
of killer whales, sperm whales and pacific white-sided dolphins. We used
physical oceanographic variables from moorings just below the surface
and at depth to characterize the seasonal prey habitat of these three
species of marine mammals. Although we did not have data to support an
assessment of the region prior to the warm water mass of 2014-2015, the
years following this event from 2016-2018 were explored for seasonal
ecosystem trends.