There’s an underwater disaster unfolding in the Gulf of Mexico right now that’s affecting Gulf Coast wildlife, fishermen and economies. We’ve broken it down here with six things you need to know.

1. Lots of rain in the Midwest means lots of freshwater entering the Gulf of Mexico

The heavy rains that hit the Midwest this spring caused widespread flood damage and crop loss in the region. Now that huge amount of water has moved down the Mississippi River toward the Gulf of Mexico, and the U.S. Army Corps of Engineers has opened a spillway on the river to prevent flooding in areas like New Orleans. Having this spillway open for an unprecedented amount to time, along with extremely high river levels, has resulted in an excessive amount of freshwater entering into the Gulf.

To add insult to injury, Hurricane Barry brought more rainfall that could ultimately make a bad situation worse. Thankfully the storm dropped less rain than expected, but it’s only the first hurricane of the 2019 Atlantic hurricane season. Future storms could continue to bring more freshwater into the Gulf.

2. All the freshwater is throwing conditions in the Gulf out of whack

This huge influx of freshwater has caused problems in the northern Gulf. First, it is lowering the salinity of the waters (i.e. they are getting less salty). Second, the flood water emptying into the Gulf carries runoff from 41 percent of the continental United States. This runoff contains nutrients, such as nitrogen and phosphorus, from agricultural, urban, and industrial sources. These nutrients fuel algal growth in the Gulf causing algal blooms. When those algae die and sink, their decomposition uses up most of the oxygen near the bottom. This creates areas of low oxygen “dead zones,” where most marine life can’t survive. This happens every summer in the Gulf, but this year scientists predict the dead zone off the coasts of Texas and Louisiana could be near record in size due in part to all the freshwater from the Mississippi River.

3. The situation is putting fish and other wildlife in jeopardy

Low salinity conditions like those in the Gulf right now are harmful to fish and other wildlife. Most marine life is adapted to live within a certain salinity range and can die when the water conditions fall outside that range. Similarly, dead zones cause die-offs in species that can’t swim away from the low-oxygen waters. Together, low oxygen and low salinity water conditions can kill things like brown shrimp, oysters, speckled trout and other fish.

There have been nearly 300 reports of dolphins dying this since February this year in the northern Gulf, and many are found with lesions that are associated with exposure to too much freshwater. The numbers of strandings are almost triple the average, which has spurred the National Oceanic and Atmospheric Administration to declare an Unusual Mortality Event for bottlenose dolphins in the northern Gulf. This declaration allows for more thorough investigation and frees up funding to better understand the problem.

Sea turtles don’t appear to be as affected by the recent influx of fresh water. However, scientists are concerned sea turtles may suffer indirectly because the prey they eat and their habitat are both impacted by the lower salinity water.

4. When fish are affected, so are fishermen

Fishermen rely on healthy waters to support populations the fish and other species they catch.

This year, commercially important species like shrimp, crab, and oysters have been severely impacted by the freshwater influx in the northern Gulf. Commercial catch of wild caught Gulf shrimp is down, shrimping season opened late in Mississippi, and signs point to fewer shrimp and shrimp that are growing more slowly. And shrimpers still have to worry about the impacts of the large dead zone predicted this summer.

Fishing groups and politicians in the Gulf have called for the declaration of a fisheries disaster for Louisiana and Mississippi as a result of the increased freshwater. State agencies in the have already started collecting data to support a federal fisheries disaster, which would provide fishermen with funding assistance.

5. We might see this situation more frequently as climate change worsens

It’s hard to know what role climate change plays in single extreme events like the heavy rains in the Midwest this spring, and urbanization and development along waterways play a clear role in the flooding that resulted. But, this sort of heavy rainfall in the Midwest falls in line with predictions for what a warmer climate will bring, and we might expect it to happen more frequently in the future.

Climate change will continue to affect our coastal ecosystems, communities, and economies in serious ways. In the Gulf, it might manifest through increased freshwater and more algal blooms that will kill fish and wildlife. In another place, it might mean ocean acidification and lower oxygen waters that make it hard for fisheries to thrive. Somewhere else, warming waters will mean fish populations will move to new areas where waters are cooler. Along our coasts, fish will have to contend with many climate impacts at once, posing significant challenges for fisherman and resource managers who depend on them.

6. Keeping Gulf fish healthy is an important part of the solution for fisheries

Keeping Gulf fisheries healthy is a big task that isn’t getting any easier with climate change. Aside from drastically reducing emissions of greenhouse gases to slow the pace of warming, fighting climate change means bolstering our ecosystems, adapting to changing conditions, and managing resources like fisheries so they are more resilient. We can help do that in a few ways.

First, we need to keep our fisheries healthy through science-based sustainable management and the rebuilding of overfished populations. In the Gulf, this also means understanding and better managing the land/sea interactions so we can reduce our upstream impacts on ocean resources. Second, storms and human activities can put pressure on fish populations by damaging important habitat. We need habitat protection and restoration to ensure that these habitats, such as wetlands and oyster reefs, continue sustaining fish populations and fortifying coastal communities. Third, we need to help fishermen and fishing communities prepare for change, for example, by putting plans and policies in place to deal with everything from more frequent fisheries disasters to the impacts of sea level rise on harbors and ports.

Everything is Connected

Decisions made ‘up-stream’ have impacts on the ocean. Everything in the environment is interconnected. We need to better understand and protect our ocean to ensure a healthy future for everyone.

What happens to the ocean impacts all of us. The ocean is our responsibility, but we can’t do it alone—we need to join forces with you and people around the world to keep our ocean and our coastal communities healthy and prosperous.