New research on the Pacific Northwest portion of the Dungeness crab fishery, which spans the West Coast of the U.S. and Canada, projects how this crustacean will fare under climate change.

Results show that by the end of this century, lower-oxygen water will pose the biggest threat. And while these crabs start as tiny, free-floating larvae, it’s the sharp-clawed adults that will be most vulnerable, specifically to lower-oxygen coastal waters in summer.

The open-access from researchers at the 91̽��, the University of Connecticut and the National Oceanic and Atmospheric Administration will be in the December issue of AGU Advances, a journal of the American Geophysical Union.

“Including all life stages allowed us to identify a critical life stage, and thus make a management recommendation,” said co-author at the University of Connecticut, who began the study while at the UW. “Looking seasonally, instead of annually, gives different — and more severe — vulnerability estimates.”

Dungeness crab is the largest single-species fishery in the Northwestern U.S. Washington’s Dungeness Crab Festival takes place in October near the Dungeness Cove that gives the species its name, and the crustacean is a favorite of Pacific Northwest holiday meals and in traditional diets. The study was designed in consultation with the Hoh, Makah, Quileute and Quinault Indian Nation tribes, whose members harvest, study and eat Dungeness crab on Washington’s Olympic Peninsula.

The researchers used a detailed computer model of ocean conditions to simulate the shifting properties of the water the crabs inhabit. Using a scenario of high carbon emissions through 2100, the model looks at how heat-trapping gases in the atmosphere will make the ocean warmer, carbon dioxide transferred from the air will make the surface waters more acidic, and warmer water will hold less dissolved oxygen.

Previous research has shown that the Dungeness crab is vulnerable to climate change. Those studies focused on changes in ocean pH, while the new paper includes multiple ocean properties and uses a model that is more detailed in space and time.

Time and place are both important. Crabs mate in spring and females produce eggs in late fall. Eggs begin to hatch in January and release larvae, which float in the offshore currents while growing, shedding and regrowing their shells five times. In summer the fully developed larvae come back closer to shore and molt, becoming juvenile crabs that scamper on the ocean floor.

The authors used an ocean model to study the consequences of climate stressors at different times throughout the Dungeness crab’s life stages — from eggs, to larvae, to juveniles, to adults.

“We found that for all three stressors there will be increased population-level vulnerability, and the most severe is to low oxygen levels,” said first author , a doctoral student at the University of Connecticut. “Low-oxygen events happen during the coastal upwelling season in spring and summer, which impacts the adults, whereas ocean acidification manifests more year-round in the future, impacting all life stages but less severely.”

Lab studies of Dungeness crab combined with model results suggest that the most severe effects will be lower dissolved oxygen along the coastal seafloor in summer, harming the adults. This is unlike other species, such as shellfish, which are thought to be most vulnerable in the larval stage.

Like other animals, crabs breathe oxygen. Warmer water holds less gas, so even if marine life can handle the higher temperature and acidity, the drop in oxygen may lower the chance for survival.

“The value of this down-scaled model is that it can help tribes and state agencies to focus their efforts in both space and time,” said co-author , an oceanographer at the 91̽��Applied Physics Laboratory and co-director of the . “This information is very pertinent to resource managers.”

The researchers say these results could be incorporated into decision-making as ocean conditions change.

“An example would be monitoring low-oxygen events in the summer, and maybe pulling the crab traps earlier,” Berger said. “This would help mitigate from the crabs dying in the trap.”

Further research on the Dungeness crab should include more lab studies on how the species responds to multiple stressors. More generally, authors say, the study shows a way to understand how marine species with complex life stages will respond to climate change.

Other co-authors are and at the UW-based Cooperative Institute for Climate, Ocean and Ecosystem Studies; and at the National Oceanic and Atmospheric Administration; and at the University of Connecticut.

The research was funded by NOAA and was part of a regional vulnerability assessment for the Olympic Coast to ocean acidification.

For more information, contact Siedlecki at samantha.siedlecki@uconn.edu, Newton at janewton@uw.edu and Berger at halle.berger@uconn.edu.

NOAA grant: NA17OAR0170166

Part of this text was adapted from a by the University of Connecticut.

Researchers from the 91̽�� and the National Oceanic and Atmospheric Administration have created a seasonal outlook for the Pacific Northwest waters, which would help tell if it’s going to be a great year for sardines or a poor crab season. A evaluating the forecast’s performance was published in June in the interdisciplinary, open-access journal .

“Ocean forecasting is a growing field, and the Pacific Northwest coast is a particularly good place to use this approach,” said lead author , a research scientist at the UW-based . “This paper is doing what the scientific community asks of a new tool, which is assessing how well it performs.”

The tool, called , or J-SCOPE, in summer 2013. The new paper is the first formal evaluation of how well it works. Analysis of the first three years of forecasts confirms that they do have measurable skill on seasonal timescales.

The seasonal for water oxygen, temperature, chlorophyll and pH along the coast of Washington, Oregon, Puget Sound and Canada’s Vancouver Island have been posted for the past three years on the UW-based Northwest Association of Networked Ocean Observing Systems website. That site now offers a comparison between the forecasted values and the long-term average, and the probability for different scenarios.

“The forecasts have been evolving over the years,” Siedlecki said. “We’re trying now to put the forecast in context — is this better or worse than in recent years?”

Analyses in the new paper show that the tool does especially well at the beginning of the spring upwelling season and matches observations most closely below the surface. This is good, Siedlecki said, because that’s exactly where measurements are scarce.

“Our tool has more skill in the subsurface, for things like bottom temperature and bottom oxygen,” she said. “That’s exciting because it can inform us where and when the low-oxygen and corrosive conditions that can be stressful to marine life would likely develop.”

The fall season is more storm-driven, she said, and consequently difficult to predict.

The tool takes long-term NOAA forecasts and combines those with a regional ocean model to produce the outlook. The goal is to eventually combine the ocean forecasts with fisheries management, so that decisions surrounding quotas could take into account the conditions for the species’ habitat during the coming season.

A was recently added and was the focus of a separate NOAA-led published this winter in Fisheries Oceanography. That forecast shows moderate skill in predicting sardine populations five or more months out.

The group now has funding from NOAA’s Northwest Fisheries Science Center to work on forecasts for , also known as Pacific whiting, since the widely-fished species lives below the surface and seems sensitive to oxygen concentrations. The researchers are interested in developing similar forecasts for salmon and other species.

Forecasted values include pH and aragonite, a calcium-containing mineral that marine animals use to harden their shells, so the tool can also help predict which months will have good conditions for growing shellfish.

“The oyster industry has already been treating the intake seawater coming into the hatcheries,” Siedlecki said. “If our forecasts can help the growers identify times of year that would be most suitable to set up juvenile oysters out in the open ocean, that would potentially help them get a leg up on changing conditions.”

For this summer, the outlook may be good news for ocean swimmers who like warm water and bottom-dwelling fish that sometimes struggle to breathe in the late summer or early fall.

“The current forecast is showing weak upwelling, warmer temperatures and higher oxygen than we’ve had in the past, so a bit of a relief in some ways for the ecosystem,” Siedlecki said.

Co-authors on the new paper are , , and at the 91̽��and , , , and at NOAA.

Development of the tool was funded by NOAA through its Program, , and , and the NOAA-run .

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For more information, contact Siedlecki at 206-616-7328 or siedlesa@uw.edu.

“Being able to predict future phytoplankton blooms, ocean temperatures and low-oxygen events could help fisheries managers,” said , a research scientist at the UW-based .

“This is an experiment to produce the first seasonal prediction system for the ocean ecosystem. We are excited about the initial results, but there is more to learn and explore about this tool – not only in terms of the science, but also in terms of its application,” she said.

In January, when the prototype was launched, it predicted unusually low oxygen this summer off the Olympic coast. People scoffed. But when an unusual low-oxygen patch developed off the Washington coast in July, some skeptics began to take the tool more seriously. The new tool predicts that low-oxygen trend will continue, and worsen, in coming months.

“We’re taking the global climate model simulations and applying them to our coastal waters,” said , a 91̽��research meteorologist. “What’s cutting edge is how the tool connects the ocean chemistry and biology.”

Bond’s research typically involves predicting ocean conditions decades in advance. But as Washington’s state climatologist he distributes quarterly forecasts of the weather. With this project he decided to combine the two, taking a seasonal approach to marine forecasts.

The National Oceanographic and Atmospheric Administration funded the project to create the tool and publish the two initial forecasts.

“Simply knowing if things are likely to get better, or worse, or stay the same, would be really useful,” said collaborator , a biologist at NOAA’s Northwest Fisheries Science Center.

Early warning of negative trends, for example, could help to set quotas.

“Once you overharvest, a lot of regulations kick in,” Levin said. “By avoiding overfishing you don’t get penalized, you keep the stock healthier and you’re able to maintain fishing at a sustainable level.”

The is named the JISAO Seasonal Coastal Ocean Prediction of the Ecosystem, which the scientist dubbed J-SCOPE. It’s still in its testing stage. It remains to be seen whether the low-oxygen prediction was just beginner’s luck or is proof the tool can predict where strong phytoplankton blooms will end up causing low-oxygen conditions, Siedlecki said.

The tool uses global climate models that can predict elements of the weather up to nine months in advance. It feeds those results into a developed by the 91̽��Coastal Modeling Group that simulates the intricate subsea canyons, shelf breaks and river plumes of the Pacific Northwest coastline. Siedlecki added a new that calculates where currents and chemistry promote the growth of marine plants, or phytoplankton, and where those plants will decompose and, in turn, affect oxygen levels and other properties of the ocean water.

The end product is a for Washington and Oregon sea surface temperatures, oxygen at various depths, acidity, and chlorophyll, a measure of the marine plants that feed most fish. Coming this fall are sardine habitat maps. Eventually researchers would like to publish forecasts specific to other fish, such as tuna and salmon.

The researchers fine-tuned their model by comparing results for past seasons with actual measurements collected by the , or NANOOS. The UW-based association is hosting the forecasts as a forward-looking complement to its growing archive of Pacific Northwest ocean observations.

Siedlecki’s analyses suggest the new tool is able to predict elements of the ocean ecosystem up to six months in advance.

Researchers will present the project this year to the , the regulatory body for West Coast fisheries, and will work with NANOOS to reach tribal, state, and local fisheries managers.

If the forecasts prove reliable, they could eventually be part of a new management approach that requires knowing and predicting how different parts of the ocean ecosystem interact.

“The climate predictions have gotten to the point where they have six-month predictability globally, and the physics of the regional model and observational network are at the point where we’re able to do this project,” Siedlecki said.

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For more information, contact Siedlecki at 206-616-7328 or siedlesa@uw.edu and Bond at 206-526-6459 or nab3met@uw.edu.