Seagrass growth in Tampa Bay is at its highest level since 2016
By Steve Newborn
March 28, 2025 at 11:00 AM EDT
A new study shows while it's growing in one part of Tampa Bay, it's decreasing in another section.
A new survey shows Tampa Bay supports the largest amount of seagrass since 2016.
Grasses that feed fish and marine life went up about 5% between 2022 and 2024, or about 1,407 acres. Tampa Bay now harbors 31,544 acres of seagrass.
Most of that gain was in Hillsborough Bay, which is on the east side of the Tampa peninsula.
Maya Burke, assistant director of the Tampa Bay Estuary Program, said one reason may be the survey was completed before last fall's spate of hurricanes. Rain can bring nutrients into the bay, which spawns algae that smothers seagrass.
"I think the most influential factor is the fact that we've had several dry years," Burke said. "I know that sounds weird right now, because we're coming off of such an extreme hurricane season and a really wet year,in 2024, but the aerial imagery that was flown to collect these maps was flown in the very earliest part of 2024. So all of that happened before Helene, Debby, and Milton.
"That means we don't have a lot of stormwater runoff to the bay. Water clarity tends to respond pretty quickly to those kinds of conditions. So with those, that really clear water, you tend to see sea grass resources recovering."
Seagrasses are a primary source of food and shelter for fish and marine life.
Map of seagrass changes in Tampa Bay (524x693, AR: 0.7561327561327561)
But it's not all good news. Most of the seagrass growth is in Hillsborough Bay, in the northeast corner of Tampa Bay. The section around the Courtney Campbell Causeway, called Old Tampa Bay, continues to see a loss of seagrass.
Old Tampa Bay lost 327 acres of seagrass, marking a new historic low there.
Burke said there needs to be better filtering of stormwater before it can flow into that part of the bay.
"So we need to do things like look at our wastewater discharges in that base segment and see if we can eliminate those discharges, not put that treated wastewater into old Tampa Bay," Burke said.
Stormwater that is not treated can mean nutrients cascade into the bay with each rainstorm. That can spur the growth of algae, which reduces the amount of sunlight seagrasses need to grow.
"We need to look at things like the water that's coming out of the Lake Tarpon outfall canal. Is that something that, instead of discharging it into the bay, we can instead use it beneficially as an as an alternative drinking water supply?" Burke asked. "Tampa Bay Water is looking at doing that very thing as part of their long term water supply planning program."
Seagrass is mapped along the bottom of the bay (1138x700, AR: 1.6257142857142857)
Grasses that feed fish and marine life went up about 5% between 2022 and 2024, or about 1,407 acres. Tampa Bay now harbors 31,544 acres of seagrass.
Most of that gain was in Hillsborough Bay, which is on the east side of the Tampa peninsula.
Maya Burke, assistant director of the Tampa Bay Estuary Program, said one reason may be the survey was completed before last fall's spate of hurricanes. Rain can bring nutrients into the bay, which spawns algae that smothers seagrass.
"I think the most influential factor is the fact that we've had several dry years," Burke said. "I know that sounds weird right now, because we're coming off of such an extreme hurricane season and a really wet year,in 2024, but the aerial imagery that was flown to collect these maps was flown in the very earliest part of 2024. So all of that happened before Helene, Debby, and Milton.
"That means we don't have a lot of stormwater runoff to the bay. Water clarity tends to respond pretty quickly to those kinds of conditions. So with those, that really clear water, you tend to see sea grass resources recovering."
Seagrasses are a primary source of food and shelter for fish and marine life.
Map of seagrass changes in Tampa Bay (524x693, AR: 0.7561327561327561)
But it's not all good news. Most of the seagrass growth is in Hillsborough Bay, in the northeast corner of Tampa Bay. The section around the Courtney Campbell Causeway, called Old Tampa Bay, continues to see a loss of seagrass.
Old Tampa Bay lost 327 acres of seagrass, marking a new historic low there.
Burke said there needs to be better filtering of stormwater before it can flow into that part of the bay.
"So we need to do things like look at our wastewater discharges in that base segment and see if we can eliminate those discharges, not put that treated wastewater into old Tampa Bay," Burke said.
Stormwater that is not treated can mean nutrients cascade into the bay with each rainstorm. That can spur the growth of algae, which reduces the amount of sunlight seagrasses need to grow.
"We need to look at things like the water that's coming out of the Lake Tarpon outfall canal. Is that something that, instead of discharging it into the bay, we can instead use it beneficially as an as an alternative drinking water supply?" Burke asked. "Tampa Bay Water is looking at doing that very thing as part of their long term water supply planning program."
Seagrass is mapped along the bottom of the bay (1138x700, AR: 1.6257142857142857)