Are Stronger, More Frequent Hurricanes a Threat to Open Ocean Aquaculture?
Although June 1 marked the first day of hurricane season in the North Atlantic, 2020 is the sixth straight year in which a named storm arrived early. Tropical Storm Arthur formed on May 16 just north of the Bahamas and passed close to the Carolinas before turning offshore. It was followed by Tropical Storm Bertha on May 27, which made landfall near Charleston before moving up towards Charlotte.
It may just be that kind of year. Due mainly to low El Niño activity, the National Oceanic and Atmospheric Administration is predicts a 60 percent chance of an active Atlantic hurricane season, with up to 19 named storms and up to six major hurricanes.
“NOAA’s analysis of current and seasonal atmospheric conditions reveals a recipe for an active Atlantic hurricane season this year,” said Neil Jacobs, acting NOAA administrator.
Many people are rolling their eyes, recalling the record-setting 2017 hurricane season when Category 4 hurricanes Harvey, Irma and Maria all made landfall in the United States, decimating some areas. Puerto Rico, in particular, was nearly uninhabitable following the extreme storm activity.
A Troubling Trend
Unfortunately this may be the new normal. A recent study led by scientists at NOAA’s Center for Weather and Climate indicates that more hurricanes – and more strong hurricanes (Category 3 or higher) – are forming. The study found that the number of hurricanes has increased 8 percent worldwide over the last decade, but that the North Atlantic has seen a shocking 49 percent increase.
Although climate models have long anticipated an increase in hurricane activity, this study is the first time it has been demonstrated using historical data. The cause is believed to be a warming ocean, which contributes more energy to the storms.
Impact on Fish Farming
What does this mean for the aquaculture industry? It’s certainly bad news for farms that have fish pens, grids, feed systems and other infrastructure at the surface. During extreme weather events, surface pens can be damaged, allowing fish to escape. This can be a major financial blow to the farmers, especially newer operations or smaller scale farms, and the escaped fish are a concern to environmentalists.
With the recent executive order to streamline aquaculture regulation in the United States and the reintroduction of the AQUAA Act in Congress, many people in the U.S. are looking with renewed vigor at where ocean-based aquaculture might develop and how the industry will operate. The Gulf of Mexico has been targeted as an area of interest by several organizations, but any development there will have to account for hurricanes as a regular occurrence.
A Global Concern
An increase in hurricanes will affect other countries as well. A study by Rebecca Gentry and her team at the Bren School at the University of California Santa Barbara identifies Latin America and Southeast Asia as two regions that have a very high potential for ocean-based aquaculture. But thus far neither region has been able to successfully develop an open ocean aquaculture industry largely because of the threat of hurricanes and typhoons.
If the problem of more frequent and stronger storms persists across the globe, it would mean an increased reliance on a limited number of protected bays and inlets that, in some places, are already becoming overcrowded with fish pens.
The Submersible Solution
One way to deal with storms and rough surface conditions is to submerge fish pens and grids. Wave energy dissipates at deeper depths. At only half a wavelength below the surface, wave energy almost disappears.
By installing a grid 50 feet deep with no surface buoys and using submerged pens, the energy experienced by the system is dramatically reduced. And submersible systems not only escape the intense waves of storms, but they are also spared regular wear and tear from normal waves that move, rub, chafe, and jerk system components relentlessly all day every day.
This strategy has been used successfully to produce fish in many locations that experience significant storms. In 2004, one of Innovasea’s submerged SeaStations in the Bahamas was hit by a Category 4 Hurricane Frances. The pen was fine and fish were harvested from it with no issues later that week.
Wave of the Future
Submersible pens like Innovasea’s SeaStation and Evolution Pen have successfully operated in active hurricane zones for almost two decades. In fact, submersible fish farming technology has advanced such that there are very few differences in how submerged farms and surface farms are operated.
Today submerged feed distribution systems enable feeding without having delicate feed hoses at the surface. Wireless underwater acoustic communication systems and sensors provide operators with vital farm data in real time. Even stocking juvenile fish into pens can be done without bringing pens to the surface.
The open ocean holds enormous potential for the future of aquaculture, allowing operators to move into deeper, cleaner waters for fish and into less crowded areas. And while stronger and more frequent hurricanes aren’t welcome news to anyone, their impact on open ocean aquaculture can be minimized by the use of the right submersible solutions and the latest technological advancements.