Investigators: Dr. Dawn Barlow, Dr. Leigh Torres, Dr. Holger Klinck, Dr. Melanie Fewings, Jennifer Fisher, Dr. Maria Kavanaugh, Marissa Garcia, Craig Hayslip, Dr. Rachel Kaplan, Will Kennerley, Mariam Alsaid

The Holistic Assessment of Living Marine Resources off Oregon (HALO) project focuses on the Northern California Current, a productive upwelling ecosystem with a rich history of research on ocean conditions and marine biodiversity. By integrating long-term ocean observations and species occurrence monitoring with satellite remote sensing, we aim to improve understanding of how changes in the environment propagate through the food web, from physics to plankton to whales.

The goals of the HALO project are to:

  1. Monitor marine biodiversity through time, across a range of environmental conditions;
  2. Quantify time lags between physical ocean conditions, phytoplankton community composition, krill biomass, and baleen whale occurrence and behavior;
  3. Improve mechanistic understanding of how environmental variability influences biological responses across multiple trophic levels; and
  4. Evaluate which satellite-derived ocean measurements are most effective for predicting the distribution and occurrence of higher trophic level species such as baleen whales.

Using a combination of physical and biological oceanographic measurements, passive acoustic monitoring, and visual surveys, the HALO project links environmental conditions to biological patterns across space and time.

 

Building on a legacy of oceanographic research in Oregon waters

Since the 1960s, researchers have conducted oceanographic studies in Oregon waters along the Newport Hydrographic (NH) Line, collecting information on water column properties and the plankton community year-round. Since 2014, the Ocean Observatories Initiative established additional monitoring platforms in Oregon waters to collect high-quality, integrated oceanographic data. The Marine Biodiversity Observation Network Pacific Northwest regional node further integrates these monitoring efforts, combining historical measurements and modern technologies. Since 2018, we have been conducting visual surveys for marine mammals (see the OPAL and MOSAIC projects), and since 2021, we have been collecting acoustic recordings, thereby adding higher trophic level species monitoring to the decades-long oceanographic timeseries’ in this region.

The wealth of data collection across scales and trophic levels provides a unique opportunity to understand how readily accessible satellite remote sensing data (e.g., sea surface temperature, chlorophyll concentration), can be harnessed to understand and predict species occurrence, particularly for times or locations when a wealth of in situ information may not be available.

 
Passive Acoustic Monitoring

Marine mammals regularly produce species-specific sounds ranging from infrasonic (< 20 Hz; e.g., blue whales) to ultrasonic (>20 kHz; e.g., beaked whales). Acoustic recordings can therefore reveal a great deal of information about species occurrence patterns, along with the ecosystem they inhabit.

The HALO project includes three Rockhopper units deployed along the NH Line: on the continental shelf (20 nm offshore), at the shelf break (45 nm offshore), and on the abyssal plain (65 nm offshore). These deployment locations represent very different environments with different oceanographic conditions.

 

Visual Surveys

We conduct visual surveys for cetaceans using standardized distance sampling, which is a common approach to estimate cetacean distribution and density. During our surveys, we record the survey conditions (i.e., wind speed, swell height, rain, fog) as these environmental factors affect our ability to detect cetaceans. We constantly record our trackline using a GPS, travel at a standard speed, and have two observers surveying for cetaceans. This consistency allows us to record and compare “absence data”, which is just as important as presence data because it tells us where the animals are not. When we make a cetacean sighting, we record the distance and bearing to the sighting, which allows us to calculate the location of the animal, based on the position of the research vessel and the height of the observer above the water. We document the species and group size, and take photos to help with identification efforts. Through the OPAL, MOSAIC, and HALO projects, we have amassed a visual survey dataset with survey effort greater than the circumference of the Earth! This visual survey dataset will provide a valuable comparison to the species occurrence patterns identified by the acoustic recordings.

Simultaneously, a trained observer surveys for seabirds, recording the species, group size, behavior, and flight height of all birds that pass within 300 meters of the research vessel trackline. 

During visual surveys, we also operate an echosounder system to map the prey distributions and densities. So, while we use passive acoustics to listen to whales, we use active acoustics to see their prey. Our 38 kHz and 120 kHz transducers are well suited for identifying krill, the dominant prey group of many whale species off the Oregon Coast. Krill tend to form dense aggregations that we can identify from active acoustic data, and measure attributes such as their depth, density, shape, and size.

 

Collaborators:

K. Lisa Yang Center for Conservation Bioacoustics, Cornell University

Cooperative Institute for Marine Resource and Ecosystem Studies

Marine Biodiversity Observation Network

KrillSeeker Lab, Oregon State University

Seabird Oceanography Lab, Oregon State University

Marine Mammal Institute, Oregon State University

 

Funding: 

National Aeronautics and Space Administration Biological Diversity and Ecological Conservation Program

OSU Marine Mammal Institute Gray Whale License Plate Funds

 

Blogs:

Using a combination of physical and biological oceanographic measurements, passive acoustic monitoring, and visual surveys, the HALO project links environmental conditions to biological patterns across space and time.