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CHNEP Seagrass Fact Sheets

Below are fact sheets that break down seagrass conditions by basin in the CHNEP area as well as more information as why they are important indicators of estuarine health and water quality:

Seagrass Bed
Seagrass meadow


Florida seagrass beds are an extremely valuable natural resource. Over 2.2 million acres of seagrass have been mapped in estuarine and nearshore Florida waters. Many economically important fish and shellfish species depend on seagrass beds during critical stages of their life history, and seagrasses play a role in carbon sequestration, nutrient cycles, stabilizing sediments, and maintaining coastal biodiversity.

Seagrass is recognized by state, federal, and local agencies as critical habitat. Estuary specific restoration and water quality goals have been established to support seagrass recovery. Given the value of seagrass beds, many agencies in Florida now monitor and track the health and status of seagrasses regularly.


Florida had historical declines in seagrass acreage during the 20th century. Seagrass requires clean water and ample sunlight to grow. Because seagrass thrives in clean and clear water- it is used by agencies and local governments as a way to measure water quality. National Estuary Programs and Water Management Districts collaborate with local governments and industry to improve water clarity and as a result of their efforts seagrass acreage in some estuaries is stable or increasing. This is done in two ways:

  • Mapping changes in seagrass acreage and location over time with aerial photography (spatial coverage). This is valuable for estimating seagrass locations, acres and broad changes over time.

  • On-the-ground monitoring of changes in species composition, estimation of bottom cover in a seagrass bed (abundance), and maximum depth in which seagrass can grow due to light availability and water clarity (deep edge). This monitoring works to characterize the density, complexity, and stability of those seagrass meadows.


Seagrass, those underwater plants that form the base of the food chain, supporting critters too small to see up to sport fish and endangered manatees. For years, it was slowly but steadily increasing in Charlotte Harbor; a positive sign in that it generally requires good water quality. Now a report being released by the Southwest Florida Water Management District shows it is shrinking in both the area it covers and in quality; while a new aquatic plant, macroalgae, is taking over large swaths of the Harbor. In fact, Charlotte Harbor and Lemon Bay’s seagrass coverage has now dropped to the levels of when mapping began back in 1988 – more than three decades of recovery lost in just two short years.

This has us water professionals very concerned, because it indicates a system tipping the wrong direction into decline. Seagrass loss can be a symptom of a serious water quality problem that is becoming all too common throughout Florida: nutrient pollution. Nutrient pollution comes from a variety of sources such as failing septics, wastewater spills (both sewage and industrial), stormwater (including residential fertilizer runoff), agricultural runoff, amongst other sources. The Coastal & Heartland National Estuary Partnership (CHNEP) of the US Environmental Protection Agency has been working to reduce this type of pollution through doing research and a variety of restoration projects over many years. Our local, state and federal governmental members are investing millions of dollars to upgrade stormwater and wastewater systems, implementing fertilizer restrictions and other measures as well.

So are those measures not working? No, the science is telling us they are not only working but are crucial for restoring water quality and seagrass. This does however underscore that much more of those actions, and others, are urgently needed. The truth is that decades of pollution have now caught up to us, accumulating in everything from the sandy sediments at the bottom of our waterways to now circulating through our waters in the harmful algae that feed upon those nutrients and then releases it back as it decomposes.

Our estuaries are sickly obese and now have to be put on a strict nutrient diet. We need to continue restoration projects to remove nutrients already in our waters, while further restricting new pollution from entering them.  And this needs to happen not only in Charlotte Harbor but across Florida and even the United States and the world. See, the water in Charlotte Harbor not only comes down the Peace and Myakka Rivers and all the smaller waterways that feed into those rivers, but it is also circulates in from the Caloosahatchee River and even the Gulf of Mexico, which the mighty Mississippi feeds into. All of those waters are also bringing in nutrient pollution.

The old adage of think globally, act locally applies here. We all are to one degree or another part of this problem, but equally we can all be part of its solution. And like any diet, this is not going to be easy and will require significant lifestyle changes. Along with substantial financial investments and new policies, we will have to collaborate across all levels of government along with agriculture and industry to make those needed changes. Us all pitching in to help these waters shed their excess nutrient weight will give them the chance to they need to rebalance and recover. The CHNEP is in this for long-haul, and we invite you to join the effort whether through us or the many other avenues in our community to get involved.

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