Predicting Fish Habitats Months In Advance With New Ocean Forecast
As meteorological science advances, we have all become used to long-term weather forecasts, such as predicting what the coming winter might bring. A new study from the University of Washington and federal scientists, however, has developed the first long-term forecast of conditions that matter for Pacific Northwest fisheries.
“Being able to predict future phytoplankton blooms, ocean temperatures and low-oxygen events could help fisheries managers,” said Samantha Siedlecki, a research scientist at the UW-based Joint Institute for the Study of the Atmosphere and Ocean.
“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.
The prototype was launched in January of this year. When it immediately predicted low oxygen this summer off the Olympic coast, people scoffed. However, some skeptics began to take the new tool more seriously when an unusual low-oxygen patch developed off the Washington coast in July. The prototype has predicted the low-oxygen trend will continue, becoming worse in the coming months.
“We’re taking the global climate model simulations and applying them to our coastal waters,” said Nick Bond, a UW research meteorologist and Washington’s state climatologist. “What’s cutting edge is how the tool connects the ocean chemistry and biology.”
Typically, Bond’s research concerns predicting ocean conditions decades in advance. The forecasts he distributes in his job as state climatologist, however, are quarterly weather predictions. He decided to combine the two with this project, creating a season approach to marine forecasts.
“Simply knowing if things are likely to get better, or worse, or stay the same, would be really useful,” said collaborator Phil Levin, a biologist at NOAA’s Northwest Fisheries Science Center.
For example, if fisheries had early warning of negative trends, it could help them 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 new tool is called the JISAO Seasonal Coastal Ocean Prediction of the Ecosystem, which the scientist dubbed J-SCOPE. J-SCOPE is still in the testing stages and it remains to be seen whether the initial low-oxygen prediction was beginner’s luck or proof it can predict regions where strong phytoplankton blooms will end up causing low-oxygen conditions.
Global climate models that can predict elements of the weather up to nine months in advance are used by J-SCOPE, which feeds those results into a regional coastal ocean model – created by the UW Coastal Modeling Group. This ocean model simulates the intricate subsea canyons, shelf breaks and river plumes of the Pacific Northwest coastline. This is combined with a new UW oxygen model developed by Siedlecki 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.
All of these calculations allow J-SCOPE to create a nine month forecast for Washington and Oregon sea surface temperatures, oxygen at various depths, acidity, and chlorophyll, a measure of the marine plants that feed most fish. This fall, the researchers plan to add sardine habitat maps. The team eventually hopes to publish forecasts specific to other fish, such as tuna and salmon.
The model was fine-tuned by comparing its results for past seasons to actual measurements collected by the Northwest Association of Networked Ocean Observing Systems (NANOOS), a UW based group that hosts the forecasts as a forward-looking complement to its growing archive of Pacific Northwest ocean observations.
The new tool should be able to predict elements of the ocean ecosystem up to six months in advance, according to Siedlecki’s analyses. If the forecasts prove as reliable as the researchers hope, they could become 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. The project will be presented to the Pacific Fishery Management Council, the regulatory body for West Coast fisheries, this year. The researchers will work with NANOOS to reach tribal, state, and local fisheries managers.