Investigators: Dr. Leigh Torres, Dr. Kim Bernard, Amanda Gladics, Craig Hayslip, Todd Chandler, Rachel Kaplan, Dr. Solène Derville, Dr. Lindsay Wickman

Summary

  • Reports of whale entanglements in fishing gear (most commonly Dungeness crab pots) have been above historic records since 2016, and are continuing to increase in Oregon
  • Project OPAL aims to improve our understanding of when and where whale distribution overlaps with fisheries
    • This improved knowledge of overlap is incorporated into management plans that support both thriving fisheries and whale populations
  • Through extensive surveys, OPAL Phase 1 (2019-2022) found that exposure to fishing gear is highest during the spring and summer months when whales are most abundant. Yearly changes in exposure risk were primarily driven by climatic fluctuations like upwelling, which increases whale habitat suitability
    • This research led to new management rules implemented in 2022, restricting commercial Dungeness crab fishing to waters less than 40 fathoms after May 1
  • OPAL Phase 2 (2023-present) will analyze a longer dataset, incorporate prey data into distribution models, investigate overlap of multiple fisheries (beyond just Dungeness crab), and look at exposure risk specific to sub-populations of humpback whales in Oregon

Whale Entanglement Project-bringing science & industry together

Background

Reports of whale entanglements in fishing gear have steadily increased in US West Coast waters, with Dungeness crab fishing gear implicated in most entanglements. Managers, researchers, fishermen, and the environmental community in Oregon are concerned about this situation because whale entanglements threaten both whale populations and the stability of the crab fishery and coastal communities. After three years of record-breaking entanglements of federally protected humpback, gray and blue whales off the US West Coast, the Oregon Whale Entanglement Working Group (OWEWG) was convened from 2017-2019, tasked with developing options to reduce entanglement risk. The group members identified that a lack of information and understanding of whale distribution in Oregon waters was a significant knowledge gap of high priority.

To fill this knowledge gap, we have teamed up with the United States Coast Guard (USCG) helicopter divisions in Oregon to conduct repeat surveys along the Oregon coast four times a month starting in 2019 (Fig. 1). Additionally, we participate in multiple interdisciplinary vessel-based research cruises off the Oregon coast to conduct marine mammal surveys and collect data on whale sightings. These research cruises include participation in NOAA’s Northern California Current Ecosystem surveys in the spring and fall, and cruises with Oregon Seagrant’s STEM at Sea program. Through continued, close collaboration with stakeholders, Oregon Department of Fisheries and Wildlife (ODFW), and the Oregon Entanglement Advisory Committee (OEAC; replacing the OWEWG in 2019), we ensure our research efforts provide useful knowledge to managers, fishermen, and coastal communities.

 

OPAL Phase 1: Habitat and phenology of rorqual whales off the Oregon coast

Using these rich datasets (Fig. 1), we have been able to describe the habitat use and distribution patterns of rorqual whales (blue, fin, and humpback whales) off the Oregon coast. In OPAL Phase 1, we analyzed year-round rorqual whale (blue, fin, and humpback) occurrence data (2016–2021, 177 survey days, 1,314 individuals observed) with state-of-the-art statistical modeling approaches to describe where we expect whales to be under certain environmental conditions.

We demonstrated (1) an increase in rorqual density over the last three decades over the continental shelf off Oregon, (2) differences in timing of migration and habitat preferences across humpback, blue, and fin whales, and (3) predictable relationships between rorqual whale distribution and dynamic ocean conditions indicative of upwelling and frontal zones. This study provides predictions of rorqual whale densities at a fine spatio-temporal scale that can facilitate targeted management of human activities in Oregon (Fig. 2).

 

OPAL Phase 1: Co-occurrence between whales and Dungeness crab fishing: 

We collaborated with the Oregon Department of Fish and Wildlife to identify patterns of co-occurrence between commercial Dungeness crab fishing gear and rorqual whales, hence assessing the spatio-temporal variations in entanglement risk over the last decade. This phase of the OPAL project identified the times and places when exposure to entanglement was the highest, using the year-round predictions of rorqual whale habitat use and maps of fishing effort compiled from logbooks (Fig. 3). With this information, managers can make informed, targeted decisions about fishing effort to maximize whale protection while minimizing burdens to fishermen.

The results of OPAL Phase 1 were integrated into new fisheries regulations in 2021, which restricts commercial Dungeness crab fishing to waters less than 40 fathoms from May 1.

 

OPAL Phase 2: Bringing in the prey

Spatial distribution patterns of marine predators are non-random within the ocean’s patchy prey-scape, and they are often highly correlated with distribution of their targeted prey. Therefore,
 OPAL Phase 2 is investigating the relationships between oceanographic variables, prey availability, and whale distribution to improve the assessment of co-occurrence between whales and anthropogenic activities.

To better understand the relationship between krill (an important prey species for fin and blue whales) and whale presence, we have analyzed krill density, caloric content, and swarm structure using active acoustics and net tows (Fig. 3). Krill and marine mammal observations for this work are collected synchronously during NOAA/NWFSC Northern California Current cruises conducted between Crescent City, California and La Push, Washington aboard the NOAA Ship Bell M. Shimada each spring (February/March) and fall (May/September).

During OPAL Phase 2, we have produced robust models of krill distribution for two species – T. spinifera and E. pacifica. By incorporating these krill data, as well as forage fish (sardine, anchovy, and herring) distribution models provided by Barbara Muhling (NOAA), we were ready to “bring in the prey” with our distribution modeling of Oregon’s rorquals.

We developed models incorporating three different predictor types: abiotic factors (i.e., oceanographic conditions), fish (sardine, anchovy, and herring), and krill (T. spinifera and E. pacifica). Given the increase of surveys in OPAL Phase 2 (395 days, 3,614 individuals observed), we were also able to model the distribution of fin, blue, and humpback whales separately (in OPAL Phase 1, these three species were analyzed together as “rorquals”). Models that incorporated prey data had improved predictive performance than models incorporating abiotic factors alone, leading to improved models of whale distribution in Oregon waters.

 

OPAL Phase 2: Distinct population segments and residency patterns

Humpback whales along the Oregon Coast are comprised of multiple sub-populations, or stocks, based on the breeding ground they migrate from (Mexico, Central America, and Hawaii). These stocks are recognized by the U.S. Endangered Species Act (ESA) as Distinct Population Segments (DPS), each with different threat classifications. Only the Hawaii DPS is considered non-threatened under the ESA; the Central America DPS is classified as Endangered and the Mexico DPS as Threatened. By understanding the distribution and residency patterns of each DPS in Oregon waters, we can further refine our estimates of entanglement risk. For example, are whales belonging to the Endangered Central America DPS particularly vulnerable to entanglement at certain times of the year, or in a certain area?

During OPAL Phase 2, we collected additional photo-identification (photo-ID) data and small tissue biopsy samples (for genetic analysis) to assign individuals to their respective DPS.  These data are collected by small boat-based teams that are mustered when aggregations of humpback whales are reported to us or observed during USCG helicopter surveys. Key to this effort are the Cetacean Ecology and Conservation Genomics Lab (CECGL; for genetic analyses), and the extensive photo-ID data provided by Cascadia Research Collective (CRC), and Happywhale.

 

OPAL Phase 2: Co-occurrence between whales and multiple fisheries: 

Currently, we are using the improved whale distribution models developed in OPAL Phase 2 to quantify the overlap between whales and multiple fixed-gear and longline fisheries, including Dungeness crab, sablefish, halibut, and spot prawn.

For humpback whales, we are further refining our estimates of risk by incorporating our estimates of the proportion of each DPS in each area (i.e., northern or southern Oregon) and time of season (Fig. 4).

 

Awards

 

Blogs

First flight

Cruising through space and time – a GEMM Lab's journey in the Northern California Current

The pathway to advancing knowledge of rorqual whale distribution off Oregon

Disentangling the whys of whale entanglement

Learning to listen to the sea

Rorquals of the California Current

"Roger that, we are currently enamored"

The room where it happens

Marine mammals of the Northern California Current, 2020 edition

Tales from the birds in the nest (on the ship at sea)

The teamwork of conservation science

 

Media

OSU-led project aims to reduce whale entanglements in Oregon and beyond

“Thar she blows!” OSU Researchers study whale/fishing gear incursions

Daylong expedition to sea gives Waldport High students a taste of scientific research and ship life

Oregon State researchers begin to unravel whale entanglement risk factors off Oregon Coast

Watching for whales – and their food

Keeping the crabbing business from tangling whales

Commercial Dungeness crab industry leads on reducing risks to whales

 

Presentations

Speaker series 10/13/2021 Oregon Chapter of the American Cetacean Society

Speaker series 2/19/2022 Oregon Chapter of the American Cetacean Society

Research updates to the Oregon Entanglement Advisory Committee 3/16/2023

 

Collaborators

United States Coast Guard, North Bend Sector and Columbia River Sector

Oregon Department of Fish and Wildlife Marine Resources Program

Oregon Entanglement Advisory Committee (OEAC; 2019-present) and Oregon Whale Entanglement Working Group (OWEWG; 2017-2019)

Oregon Dungeness Crab Commission

Cascadia Research Collective

OSU Cetacean Conservation and Genomics Laboratory

Barbara Muhling, NOAA Southwest Fisheries Science Center

 NOAA Northwest Fisheries Science Center

 

Funders

NOAA Fisheries:  Species Recovery Grants to States

Oregon Dungeness Crab Commission

Oregon Department of Fish and Wildlife

Oregon State University Marine Mammal Institute

Oregon Sea Grant

 

Publications

Kaplan RL, Bernard KS, Derville S, Fisher JL, Phillips EM, Daly EA, Warren JD, Torres LG (2025). Krill swarm biomass, energetic density, and species composition drive humpback whale distribution in the Northern California Current. ICES Journal of Marine Science, Volume 82, Issue 1. doi: 10.1093/icesjms/fsaf005

Derville, S., Fisher, J.L., Kaplan, R.L., Bernard, K.S., Phillips, E.M., Torres, L.G. (2025) A predictive krill distribution model for Euphausia pacifica and Thysanoessa spinifera using scaled acoustic backscatter in the Northern California Current. Progress in Oceanography. doi: 10.1016/j.pocean.2024.103388

Kaplan RL, Derville S, Bernard KS, Phillips EM, Torres LG (2024). Humpback-krill relationships are strongest at fine spatial scales in the Northern California Current region. Mar Ecol Prog Ser 729:219-232. doi: 10.3354/meps14510 

Derville, S., Buell, T., Corbett, K. C., Hayslip, C., Torres, L. G. (2023) Exposure of whales to entanglement risk in Dungeness crab fishing gear in Oregon, USA, reveals distinctive spatio-temporal and climatic patterns. Biological Conservation, 109989. doi: 10.1016/j.biocon.2023.109989

Derville, S, Barlow, D R, Hayslip, C, Torres, L G (2022) Seasonal, annual, and decadal distribution of three rorqual whale species relative to dynamic ocean conditions off Oregon, USA. Frontiers in Marine Science. 9, 86566. doi: 10.3389/fmars.2022.868566

 

 

Through extensive survey effort and community partnerships, our co-occurrence analyses aim to reduce whale entanglements while minimizing impacts on fishers.