Monday, October 25, 2021

Water Quality and Sea Birds | The Lost Summer of 2018

“Water Quality and Seabirds” was the fourth and last presentation in the Breakfast with the Birds series hosted by Rookery Bay Environmental Learning Center. It featured Adam DiNuovo, the shorebird monitoring and stewardship program manager for Audubon Florida.

According to DiNuovo, typically when red tide was reported on Florida beaches last year, municipalities’ greatest concern was getting those dead fish off our beaches.

Coastal cities posted “Red Tide Warning” signs. For DiNuovo, these signs don’t contain the full truth. The signs refer to red tide as natural, and suggest that there is nothing we can do about it. Red tide is occurring at a more frequent rate and the size of the blooms are bigger – because of the harmful nutrients flowing off the land. Harmful nutrients such as nitrogen and phosphorous from fertilizer combined with animal and human waste feed the growth of Karenia brevis red tide blooms as they move closer to shore.

DiNuovo has conducted a black skimmer banding project on Sand Dollar Island since 2017. In 2018, he added research into red tide. As he caught and weighed the birds, DiNuovo noticed that most of the birds were underweight.

They had sunken cheeks and looked anorexic. Typically, young birds are always hungry, but these birds did not want to eat.

A healthy young bird should weigh about 270 grams, but these young birds were weighing 100 grams less, which was a huge problem as they need to build up weight so they can fly and survive the winter. Sometimes Adam would recapture the same birds and they would lose 30-50 grams in just two days. He wanted to know why!

During the summer of 2018, the colony looked like they were having a good year with a rate of two chicks per pair of adults. In early September, most of the birds left the colony at Sand Dollar Island. Some lingered in the area. And DiNuovo began taking sick birds to the von Arx Wildlife Hospital.

The Red Tide was reported as “background” with no indication of being close to shore. According to DiNuovo, just because you can’t see or smell red tide, it does not mean it is not present in quantities that are deadly to marine life and shorebirds.

In mid-October, right after Hurricane Michael, a large colony of least terns arrived on Marco’s beach numbering in the tens of thousands. The birds hung around until the colony dwindled to about 5,000, and getting lesser each day.

DiNuovo started seeing sick birds with unusual symptoms, and in early November began the progressive shorebird die-offs. DiNuovo and his team of beach volunteers worked daily, three times a day for eight weeks, picking up sick and dead birds, taking the sick ones to the von Arx Wildlife Clinic, where 98% of the birds did not survive the journey.

The report of dying birds and sick birds falling from the sky began to attract state and federal concern. Tissue samples were sent off for analysis to state and federal laboratories in order to determine why the birds were dying at such a rapid rate. And yes, they confirmed the presence of brevetoxin (Karenia brevis) in the tissues of dead birds.

DiNuovo hypothesized that the presence of brevetoxin may have been one of the main stressors, coupled with the likely presence of coccidiosis (a parasite common to seabirds) weakening the immune system. But for DiNuovo, this may not be the full story.

Can this happen again? DiNuovo emphasized that we all may have had a role to play in the massive fish and bird-die-offs in the summer of 2018 — but we can all play a better role in making sure that our island water is cleaner as it flows into the Gulf of Mexico.

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