Please select your home edition
Edition
Ocean Safety 2021 - LEADERBOARD

String of marine heatwaves continue to dominate Northeast Pacific

by NOAA Fisheries 13 Dec 2020 18:04 UTC
String of marine heatwaves continue to dominate Northeast Pacific © NOAA Fisheries

During the summer of 2020, an area of unusually warm ocean water—a marine heatwave—grew off the West Coast of the United States. It became the second most expansive Northeast Pacific heatwave since monitoring began in 1982.

The heatwave eventually encompassed about 9.1 million square kilometers, almost six times the size of Alaska, towards the end of September.

In 2019 a similar heatwave developed slightly earlier in the year. While it was not as extensive as this year's heatwave, its surface expression was warmer. It lasted 239 days, finally dying out way offshore in January 2020.

The 2020 heatwave was about the same horizontal extent as 2014's massive marine heatwave known as The Blob. What's different is the 2020 heatwave extended further south and towards the coast, compared to 2019. It encompassed much of southern California, the Southern California Bight, and into Mexican waters off Baja. Additionally, the 2020 heatwave lingered nearly a month longer into the fall in coastal waters and remained very strong in the far offshore region. However, neither the 2019 nor the 2020 heatwaves reached nearly as deep as The Blob, which warmed the water at least 100 meters deep in places. The last two heatwaves penetrated only 40 to 50 meters.

The new normal?

"It's notable that in five of the last seven years, the California Current system has been dominated by these large marine heatwaves, which are also the largest heatwaves on record for this area," said Andrew Leising, a research scientist at NOAA Fisheries' Southwest Fisheries Science Center in La Jolla, California. He developed a system for tracking and measuring heatwaves in the Pacific Ocean using satellite data. The California Current Marine Heatwave Tracker automatically analyzes variation from the average sea surface temperature from 1982 to the present. Experts are also tracking and analyzing marine heatwaves across the globe.

"The question we're asking ourselves is whether these recurring heatwaves are the 'new normal' or if we'll transition back to a previous climate state," said Leising.

While some studies suggest that the warming oceans are fueling more frequent, stronger, and longer-lasting heatwaves, there are other considerations. Namely, the warming ocean itself is pushing baseline temperatures up, which may make heatwaves reach certain thresholds that exceed historical averages more often. Researchers continue to analyze ocean temperature data. They note that many questions remain about whether and how the ocean, and marine heatwaves, may be changing.

"The last few years have seen some really big marine heatwaves by any measure, but we are still teasing apart the complex factors behind them," Leising said. "That is a big question going forward: What is changing, and what does it mean for our marine ecosystems?"

What warmer conditions mean for the ecosystem

These warmer conditions have boosted the odds of harmful algal blooms, shifting distributions of marine life, and changes in the marine food web. For example, the largest and most toxic bloom of Pseudo-nitzschia ever recorded along the U.S. West Coast occurred in 2015, during the 2013-16 marine heatwave. The widespread bloom increased levels of algal toxins that collect in shellfish. That forced the closure of the Dungeness crab fishery, one of the most productive and well known West Coast fisheries.

In recent weeks, Washington authorities have closed the state's coastline to razor clamming and the central Washington Coast to Dungeness crab fishing because of high levels of algal toxins.

Ecosystem approach to monitoring heatwaves

NOAA's California Current Integrated Ecosystem Assessment is an interdisciplinary research effort led by NOAA scientists along the U.S. West Coast. It engages scientists, stakeholders, and managers to integrate all components of an ecosystem, including human needs and activities, into the decision-making process. The marine heatwave tracker was developed as a part of this effort. It helps managers consider the effects of ocean temperature on the ecosystem as a whole.

NOAA Fisheries' Southwest and Northwest Fisheries Science Centers use this approach and lessons learned from the last heatwave to anticipate and mitigate potential impacts of this new one. Scientists provide fisheries managers and stakeholders with information on how these unusually warm conditions could affect the marine ecosystem and fish stocks.

Related Articles

Rescuing thousands of sea turtles in Texas
Learn about the heroic efforts to rescue and recover cold stunned sea turtles The recent historic winter storm put much of the United States into a deep freeze. The cold snap stunned thousands of sea turtles in Texas. A massive statewide effort to save these threatened and endangered animals began on Valentine's Day weekend. Posted on 6 Mar
Killer Whale Tales' reach extends around the world
A teacher engages students with the wonder of the Southern Residents Cancellation of field trips, limited in-person classes, and other restrictions drastically changed what school looked like in 2020. Posted on 28 Feb
11 cool whale, dolphin, and porpoise facts
These animals are often referred to as "sentinels" of ocean health Marine mammals in the cetacean family include whales, dolphins, and porpoises. These animals are often referred to as "sentinels" of ocean health, providing insight into marine ecosystem dynamics. Posted on 21 Feb
North Atlantic Right Whale Calving Season 2021
The North Atlantic right whale population has been declining for the past decade The critically endangered North Atlantic right whale population has been declining for the past decade. With fewer than 400 whales left, researchers closely monitor the southeastern United States for new offspring during the calving season. Posted on 20 Feb
Coastal surveys reveal marine success stories
Data show harbor porpoise comeback and last chance for endangered turtles The Southwest Fisheries Science Center began some of our first regular aerial surveys off the coast of California in 1986. We wanted to answer a basic question: How many harbor porpoises lived along the coast, and were their numbers going up or down? Posted on 17 Feb
New genetic study to estimate age of whales
Results indicate whether Cook Inlet beluga whales are reproducing much later than initially thought The new epigenetic methodology could revolutionize the way scientists study endangered Cook Inlet beluga whales and provide valuable insights into why the population may not be recovering. Posted on 14 Feb
West Coast Gray Whales unusual mortality event
Decline resembles drop 20 years ago as it declined about 24 percent since 2016 Decline resembles drop 20 years ago, which was followed by an increase. The population of gray whales that migrate along the West Coast has declined about 24 percent since 2016. Posted on 2 Feb
Threats imperil Northeast Pacific killer whales
Vessel strikes may be an "underappreciated but important threat" to endangered orcas Vessel strikes may be an "underappreciated but important threat" to endangered orcas. Human impacts ranging from stray fishhooks to vessel strikes have killed more killer whales, including endangered Southern Resident killer whales Posted on 1 Feb
Condition of seals declined during rapid warming
A new study finds quantitative evidence of climate-related impacts on these predators A new study finds quantitative evidence of climate-related impacts on these typically adaptable, resilient predators. Posted on 30 Jan
New species of Baleen Whale in the Gulf of Mexico
NOAA Fisheries announces scientific research paper that describes the new species NOAA Fisheries announces scientific research paper that describes a new species of baleen whale in the Gulf of Mexico. Posted on 30 Jan
Stoneways Marine 2021 - FOOTERSea Sure 2021 - Blakes Toilets - FOOTERUpffront 2020 Foredeck Club SW FOOTER