The tenth State of the River Report has been released, and the detailed analysis of the health and status of the Lower St. Johns River Basin and its tributaries shows mixed results.
The report focuses on four main areas of the river’s health: water quality, fisheries, aquatic life, and contaminants. This year’s report included a section on ten-year summaries of all indicators which showed that some indicators have improved, several have worsened, and others are unchanged.
The report was presented by one of its lead researchers, Dr. Gerry Pinto, Associate Research Scientist at the Marine Science Institute of Jacksonville University, at the 2018 Environmental Symposium on Friday, Aug. 14. The event was hosted by the Jacksonville Environmental Protection Board (JEPB) and the University of North Florida on their campus.
Dr. Radha Pyati, Dean of the College of Sciences and Mathematics at Westchester University in Pennsylvania and former Chair of the Department of Chemistry at UNF, said both total nitrogen and total phosphorus levels have been showing signs of improvement.
“When those ambient nitrogen and phosphorus levels creep downward, hopefully that means that eventually we won’t be seeing as many algal blooms,” said Dr. Pyati, who co-led the report with Pinto. “The problem is that when we look at averages of total nitrogen and averages of total phosphorus, those averages don’t always take into account short term spikes in those parameters that lead to algal blooms. Algal blooms are about what’s happening in the short term. And we still see conditions that precipitate these blooms.”
Dissolved oxygen levels have also improved.
“What tends to happen in the tributaries, especially in hot summer days, is the oxygen levels drop,” said Pinto. “And that could potentially cause fish kills or organisms to die because the oxygen levels are low. If we have better flows and we have increased oxygen levels then those things don’t die.”
Over the last few years, populations of three critical threatened and endangered species have been on the rise. “Which would indicate that the environment is supporting them sufficiently,” he said.
Pinto said that 250 to 300 manatees come to the Jacksonville area every year. There are around 50 bald eagles living in the area, and a solid number of Wood Stork colonies.
Bird populations do tend to get knocked back a bit when there’s significant storm activity, according to Pinto, but over the long term numbers have been increasing. Populations of these three species are higher than they have been since the year 2000.
Salinity has been on the rise over the past two decades, and that trend is expected to continue, increasing potential negative impacts on submerged aquatic vegetation and the aquatic life that depends on it.
The report shows that there’s been some recent regrowth of submerged aquatic vegetation due to rainfall, but the long-term trend is far from certain.
Aquatic vegetation provides food for manatees, shelter and protection for the larval stages of many commercially harvested fish and blue crabs spend part of their life cycle in grass beds.
Pinto said that if that aquatic vegetation goes away, “the environment loses that carrying capacity, that ability to support all that stuff and all those species. And so that eventually will translate into economic losses for people and their livelihoods.”
He thinks we may already be seeing some of the effects of that. Blue crab harvests have declined by 10 percent over the past decade. The blue crab is the largest commercial fishery in the region.
Increasing salinity levels may be partly due to rising sea levels, Pinto believes.
According to the report, nonnative species are on the rise in the St. Johns River. In 2008 there were 56 nonnative species. In 2017 there were 80. The spread of the lionfish and Cuban treefrogs is especially concerning due to their impacts on the native ecosystem.
Pinto said that wetlands continue to be lost, largely due to development pressures.
“If we continue to take wetlands out of their useful function and fill them, for example, and develop them, we’re going to see more flooding,” Pinto said. “So we need to be careful about that. We need to do more on the restoring of wetlands side of things to alleviate some of those issues.”
The report shows that chlorophyll a levels, which are another indicator of harmful algal blooms, have not decreased.
Dr. Pyati said fecal coliform levels are far above water quality criteria in many tributaries, making them unsafe for recreation.
“Honestly, the fecal coliform problem has been a very difficult nut to crack,” said Pyati. “The City of Jacksonville and other entities, the Florida Department of Environmental Protection, have been working hard to study the sources of this fecal coliform bacteria so they can start to isolate where it’s coming from. Because a lot of effort has been put towards reducing that in these tribs [tributaries], and it’s not showing a significant drop. There are drops in some of the tribs, but not in others.”
According to the report, most fish and invertebrate species are not in danger of being overfished, except for channel and white catfish. Both of those species are in danger of being overfished in the near future.
For the full State of the River Report, which includes highlight sections on bottlenose dolphins in the St. Johns River and K-12 applications of the report, go to SJRReport.com.
Photo used under Creative Commons license.
Brendan Rivers can be reached at brivers@wjct.org, 904-358-6396 or on Twitter at @BrendanRivers.
