ANNA MARIA ISLAND — Tropical Storm Bertha’s high winds pushed heavy surf onto Anna Maria Island beaches from July 17-22, impacting half of the loggerhead sea turtle nests laid in the sand since the start of nesting season in May.
Of the 371 nests on the beach, 189 were impacted, according to Anna Maria Island Turtle Watch and Shorebird Monitoring, with 65 nests totally washed out, six nests partially washed out, seven left standing in water and 111 washed over by high surf.
Sea turtle nests can withstand some overwash, but too much may cause the eggs to stop developing, according to Turtle Watch Executive Director Kristin Mazzarella. Heavy surf may wash away sand from the nest and expose or pull out eggs. While eggs left in the sand may still be viable after the water drains from the nest, eggs that have been moving around in the surf are unlikely to remain viable.
Rain and surf can also cool nests, causing the nest to produce more males; the gender of turtle hatchlings is determined by the temperature of the nest during a specific part of incubation, with warmer temperatures producing more females and cooler temperatures producing more males, according to Mazzarella.
The organization does not interfere when storms impact nests.
“Sea turtles have been around for millions of years and have adaptations that account for losses due to natural causes. They lay hundreds of eggs multiple times in one nesting season, likely resulting in one or two offspring that will survive to adulthood,” according to Mazzarella.
They did document the damage and recover nest stakes that washed away, reposting those nests that were still in place.
People calling the 24-hour hotline at 941-301-8434 helped alert Turtle Watch to eggs washing out and hatchlings that were found off the beach.
Beachgoers are invited to watch for nest inventories, in which hatched eggshells are counted. Hatched nests are marked with a red flag and are inventoried within three days of hatching, sometimes uncovering live hatchlings that are released.
So far this season, 2,855 sea turtle hatchlings were produced from nests on the island. Between 556 and 1,290 hatchlings were disoriented by lights, according to Turtle Watch statistics.
Least terns weather storm
The organization also monitors shorebird nesting, and reports that least terns colonies have produced between nine and 11 chicks as their season winds down, surviving Bertha.
The number of adults on the beach fluctuated from 22 to 180 as terns begin their annual migration south to the Caribbean islands and the northern coast of South America.
Chicks Persi, Vera and Nancy are flying and the youngest banded chick, Leon, took his first flight on July 24. Three other chicks ranging in age from two to four weeks continue to be fed by their parents, according to Turtle Watch.
Flightless chicks can be seen roaming outside and beyond the enclosure. When chicks feel threatened by an avian predator, they lay flat on the sand and can be difficult to see. They also hide in seaweed that has accumulated along the shoreline. Beachgoers should use caution when walking near the area.
Cindy Lane is a staff writer for the Tampa Bay Beacons. She can be reached at clane@tbnweekly.com.