Gulf of Mexico marine food web changes over the decades

March 17, 2015, NOAA Headquarters
Gulf of Mexico marine food web changes over the decades
Fish species in NOAA's Flower Garden Banks National Marine Sanctuary, off Texas. Credit: NOAA

Scientists in the Gulf of Mexico now have a better understanding of how naturally-occurring climate cycles—as well as human activities—can trigger widespread ecosystem changes that ripple through the Gulf food web and the communities dependent on it, thanks to a new study published Saturday in the journal Global Change Biology.

A team of NOAA scientists spent three years reviewing over 100 indicators derived from environmental, fishery, and economic data, including , currents, atmospheric patterns, , harvest, and revenues. Through extensive analysis, they found a major ecosystem reorganization that appeared to be timed with a naturally-occurring climate shift that occurred around 1995.

The climate phenomenon is known as the Atlantic Multidecadal Oscillation (AMO), a climate signal in the North Atlantic Ocean that switches between cool and warm phases, each lasting for 20-40 years at a time. The AMO, which was in a cool phase between 1965 until 1995 and has been in a warm phase since, influences global ocean and weather conditions in the northern hemisphere such as hurricane activity in the Atlantic ocean and the severity and frequency of droughts.

However, the AMO is not as extensively studied as other climate phenomena, such as El Nino, and this study is the first to investigate what scientists hope will be many future studies examining how the AMO influences ecosystem-scale change in the Gulf. Scientists hope this work will spur interest in further studying this phenomenon and its implications for the marine environment in this region.

"These major ecosystem shifts have probably gone unrecognized to date because they are not apparent when considering single species or individual components of the ecosystem," said lead investigator Dr. Mandy Karnauskas of NOAA's Southeast Fisheries Science Center. "Only when we put a lot of things together—including currents, hypoxia, fish abundances, fishing effort, and more—does a strong climate signal emerge."

Gulf of Mexico marine food web changes over the decades
Top left: The AMO index is shown.Bottom left: This is a 2-dimensional representation of the landings composition from 1950 to 2010. Years located more closely together are more similar in species composition.Right: This is a traffic light plot of landings data, showing the overall trends by species group, in relation to shifts in AMO phase. Credit: NOAA

Additionally, scientists observed shifts in many species around the late 1970s coincident with the advent of the U.S. Magnuson-Stevens Fishery Conservation and Management Act- a policy designed to set rules for international fishing in U.S. waters, make the expansion of certain fisheries more favorable for economic development, and ensure the long-term sustainability of the nation's fish stocks.

Other human influences that are not as pronounced—or easily distinguishable—include coastal development, agricultural runoff, oil spills, and fishing. Natural phenomena like coastal storms and hurricanes play a role as well.

The scientists expect their study to be useful to resource managers throughout the Gulf region. While managers cannot control Earth's natural cycles, they may need to consider how to alter management strategies in light of them, in order to effectively meet their mandates.

Explore further: Interaction of Atlantic and Pacific oscillations caused 'false pause' in warming

More information: Evidence of climate-driven ecosystem reorganization in the Gulf of Mexico, onlinelibrary.wiley.com/doi/10 … 1/gcb.12894/abstract

Related Stories

European fisheries flip with long-term ocean cycle

April 17, 2013

A sudden switch from herring to sardines in the English Channel in the 1930s was due to a long-term ocean cycle called the Atlantic Multidecadal Oscillation (AMO), an international study shows. This is the first evidence ...

Is the tasty blue crab's natural range creeping north?

March 6, 2015

David Johnson was standing in a salt marsh tidal creek north of Boston, Mass., when he scooped up a blue crab, Callinectes sapidus, 80 miles north of its native range. The northern migration of this commercially important ...

Recommended for you

Oceans of garbage prompt war on plastics

December 15, 2018

Faced with images of turtles smothered by plastic bags, beaches carpeted with garbage and islands of trash floating in the oceans, environmentalists say the world is waking up to the need to tackle plastic pollution at the ...

A damming trend

December 14, 2018

Hundreds of dams are being proposed for Mekong River basin in Southeast Asia. The negative social and environmental consequences—affecting everything from food security to the environment—greatly outweigh the positive ...

Data from Kilauea suggests the eruption was unprecedented

December 14, 2018

A very large team of researchers from multiple institutions in the U.S. has concluded that the Kilauea volcanic eruption that occurred over this past summer represented an unprecedented volcanic event. In their paper published ...

The long dry: global water supplies are shrinking

December 13, 2018

A global study has found a paradox: our water supplies are shrinking at the same time as climate change is generating more intense rain. And the culprit is the drying of soils, say researchers, pointing to a world where drought-like ...

Death near the shoreline, not life on land

December 13, 2018

Our understanding of when the very first animals started living on land is helped by identifying trace fossils—the tracks and trails left by ancient animals—in sedimentary rocks that were deposited on the continents.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.