seaturtle.org : MTN : ARCHIVES : Sign In

Marine Turtle Newsletter 9:2, © 1978

The Atlantic Ridley in Mexico: 1978 Season and Conservation Programme

Biól. René Márquez M.
Apdo. Postal 79-052, Col. Doctores, México 7, D.F.

This year the ridley sea turtle nesting season began in the middle of April and the last "arribada" was on June 18th, 1978. The total number of eggs transplanted to the nursery were 85833, divided in two lots, one reburied directly in the sand on the beach (65,316 eggs) and the other incubated in styrofoam boxes with 100-150 eggs per clutch. The overall hatching rate was 55.9% on the beach and 66.6% in the boxes, and the number of hatchlings released on the Rancho Nuevo beach was 53,953. The remainder were sent to the National Marine Fisheries Laboratory at Galveston, Texas. Some of the hatchlings were greens (96) and they were released at the same place and time. This year the nesting season was longer than in the five previous years and the total number of females was about double that of last year. We suppose that the population has increased, but how much has not yet been calculated.

Incubation in boxes was 10.7% more successful than incubation in natural conditions on the beach. The time for incubation was longer in the boxes, around five days more; this may be because the temperature was 2 or 3 °C lower in the boxes and small changes in weather have had more influence in small boxes than open sand beach.

For the first time, the work in Rancho Nuevo was carried out in collaboration with U.S. scientists and students. The project was called "Restoration and Enhancement of Atlantic Ridley Turtle Population". Its principal features were total protection of the turtle nesting in Rancho Nuevo, Tamaulipas, and the transportation for 2,000 eggs and a similar quantity of hatchlings to the Galveston Laboratory, for possible imprinting and head-starting of hatchlings the subsequent release taking place within the yearlings' natural distribution.