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HEATHER-LYNN’S HABITAT: Seaweed benefits


Heather-Lynn Evanson, [email protected]

HEATHER-LYNN’S HABITAT: Seaweed benefits

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THE SARGASSUM SEAWEED has been a double-edged sword for the region’s turtle population.

Last year, the thick floating rafts of seaweed were responsible for the deaths of 42 Hawksbill turtles at Long Beach, Christ Church.

The marine animals were apparently caught unawares by the quick-moving seaweed after they came up for air. The seaweed then trapped them close to the surface and, in the heat of the day, the turtles succumbed to hyperthermia.

Enriched ocean

However, the seaweed, which has disappeared as quickly as it appeared, seems to have been responsible for enriching the ocean’s nutrients.

And that was one possible reason, said field director of the Barbados Sea Turtle Project, Dr Darren Browne, why there was such a good nesting season in 2015.

In fact, instead of the nesting season petering out in September, female turtles were still coming ashore into December. A green hatchling, the straggler from a November nest, was released a few weeks ago.

“It was a busy year last year. We had quite a bit of activity down to the end of last year. Things finally started to quiet down in December. That means the hatchlings from December will still be coming up in February,” a pleased Browne told Heather-Lynn’s Habitat.

He said he was still analysing the data from last year to see to what the increase could be attributed.

“I don’t know if it had something to do with the sargassum. As a result of the sargassum, there was a lot of upwelling of nutrients in deeper water. So as the sargassum was growing, it found highly nutritious water that it was able to feed on and it became that massive influx that we experienced throughout the Caribbean,” he surmised.

Sea sponges also benefited from the enriched ocean waters. And Hawksbills feed on sea sponges.

“If the sea sponges are healthier, more abundant, then turtles get more nutrition from the sponges and, potentially, some of the females that would have taken three years to build up the nutrients necessary to nest, might take two years instead and all of them might have come up together. So you would have had turtles that would have taken an extra year, joining those turtles that normally would have come up last year,” he explained.

Drop in numbers

Of course, Browne hastened to add, it was now possible that there might be a drop in this year’s numbers since those turtles would not come up to nest.

“But if we can figure out exactly what happened, we can predict when more turtles are going to come back, we can predict when there is going to be a drop-off.”

The field director also surmised that global warming lent a helping hand to the turtle population.

A turtle’s sex is determined by the temperature of the sand in which the nest rests. The warmer the temperature, the more females there will be.

“So with global warming, we are anticipating there would be more females which then potentially means that more of what we are monitoring will be coming up,” he said.

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