Noemí Durán Royo

Predation Levels and Sea Turtle Hatchling Survival after Release from the Gulf of Fonseca, Honduras:

Implications for Conservation Management

 

SUMMARY

 

The main goal of my study was to know more about the fate of the thousands of Olive Ridley hatchlings that

are released every fall from the beaches at the South coast of Honduras. Olive Ridley turtles are common in Honduran waters and they are heavily exploited. Although the adults are not usually hunted the eggs are

highly priced and the collection of turtle nests for trade is a common practice in coastal communities.

Since the 1970s the Honduran Government has established a protected period called “la veda” from

September 1st to 25th, when the poaching of eggs is illegal. All the nests laid during this time are transferred

to a hatchery and taken care until they hatch, about forty-five days later. The babies are then released,

either from a boat, or directly from the beach.

Although the main nesting beach in the area, Punta Raton, has been monitored for the last 5 years by the

organization ProTECTOR (Protective Turtle Ecology Center for Training, Outreach, and Research, Inc),

no studies have been previously done on the fate of these hatchlings after their release. Other studies on

different sea turtle species showed that the first hours that hatchlings spend in the ocean involve the

highest risk for them and that the probability of being eaten by fish greatly increases when they remain in

shallow waters. The beach at Punta Raton is located in the east coast of an inlet of the Pacific Ocean called

the Gulf of Fonseca and the hatchlings must swim for about 30 km before reaching the open sea.

Because the waters at the gulf are very shallow in most of its extension, I was concerned about most of the

hatchlings being eaten by predators and decided study how many hatchlings were eaten and how many

survived after leaving the beach.

 

To follow a little 4.5 cm baby turtle during the night to see if something eats it is trick, so I used a device

called Whiterington float that is basically a tiny wood boat with a glowstick in the upper part that we tied to

the carapace of the hatchling by a 1 meter long string. This allowed the hatchling to swim and dive while

I could easily see the floating light and follow it with a small fishing skiff.

 

During three weeks, I went out every night for four hours and followed two hatchlings, two hours each.

Fishermen from the community drove the boat as we followed the float, took GPS positions every 5 minutes,

and watched to see if the hatchlings would be eaten by fish. Surprisingly, all our hatchlings swam calmly

during the two hour experiment and after that we recovered them, took the floats off and re-released them.

These results, although unexpected, are actually good news for the hatchlings because aquatic predation

does not seem to be a very important thread for them in the Gulf of Fonseca. One possible reason for the

absence of predation could be the low numbers of fish due to overfishing during the last decades. In fact,

local fishermen usually complain that the amount of fish keep decreasing year after year.

 

After I noticed the absence of aquatic predation I thought that probably the risk of predation by birds

during daylight hours may be more important than predation by fish in this area. I performed some

preliminary trials during the day and I am interested in studying this factor next year.

 

This study has been an extraordinary experience for me and I am very excited to continue it next summer.

To see the little baby turtles hatching and accompany them during the first phase of their trip was awesome.

I am very thankful to the Boyd Lyon Sea Turtle Fund and The Ocean Foundation for sponsoring this study

through the Boyd Lyon Scholarship. In the spirit of Boyd Lyon, who sought to improve the plight of sea turtles,

it is my desire to contribute to increasing our knowledge of Olive Ridley hatchlings, to improve the

management of sea turtles in this area, and to work toward the best possible future for all sea turtles.

 

 

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