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Marine Turtle Newsletter 4:2-3, © 1977

Crisis for the Atlantic Ridley

Letter from Professor A. Carr, Co-Chairman, IUCN Marine Turtle Group, Department of Zoology, University of Florida, Gainesville, Florida 32611 U.S.A. to Sir Peter Scott, Chairman, SSC, Slimbridge, Glos., England

"Dear Peter:

This is not the first time I have written you a panicky letter about the plight of Lepidochelys kempi, the Atlantic ridley, but it seems likely that it may be the last time. Since the IUCN last made representations to the Mexican government in respect to the plight of kempi, the situation has degenerated so badly that I must again beg you to bring the circumstances to the attention of the Survival Service Commission, at its April meetings. I deeply regret that I can't be there to say more on the subject, because it is a grave and complicated one.

Last week, while preparing to write a popular article on the ridley for the magazine Sports Illustrated, I carefully went over all available records of breeding population levels at Rancho Nuevo, the only nesting ground of the species, and I realized that we really do have a crisis on our hands. Accordingly, I went to Brownsville, Texas, for four days to gather more information. I discussed the current status of the nesting arribada with Dearl Adams, Kavanaugh Francis, and others of the corporation that has been formed at South Padre Island to save the ridley. I spent two afternoons with the Port Isabel shrimp fleet, the biggest shrimping exercise in the world. Going from trawler to trawler, I plied every shrimper who was willing to talk with exactly the same set of questions that I had asked at the same docks 16 years earlier, back in the days when the trawlers, their nets, and the periods for which the trawls stayed down, were all half what they are now; when the price of shrimp was one-eighth its current price; and when ridleys were being abundantly caught not just in Texas and Mexico but in Florida waters and northward all along the Atlantic coast.

On that first visit to the shrimp docks, there was evidence of incidentally caught ridleys everywhere. Every crewman I spoke with knew the ridley well. They said it was the only abundant sea turtle in the area, and they deplored the damage it did to the shrimp in their trawls. Last week, almost none of the shrimpers I spoke with even knew of the existence of ridleys. I was careful to indicate that my only interest was in collecting tags and paying rewards for them, and for the most part I was able to dispel apprehension that I might be an enforcement officer of some kind. I am thus quite sure that the contrast in catch frequencies that I saw is real; and it is just the same all along the ridley migration route in Florida and beyond. Few ridleys are caught anywhere now, simply because few remain.

Besides the hours I spent on the shrimp boats, I attended the convention of the Texas Shrimp Association, to try to soak up an impression of their attitude toward the incidental catch problem. Then I spent a long time conversing with René Marquez and others in Mexico City agencies, to get all existing figures on the size of the 1976 nesting aggregation.

What has happened to kempi can be graphically shown by comparing successive sizes of 3 Rancho Nuevo breeding population, as indicated by counts or estimates of arribada size during past decades. I'll list only three of these here, but the figures are representative, and we are working up a more complete record. Arribada sizes, and calculated total mature breeding population for the successive periods since the nesting land was discovered, are as shown below (I'll explain our method of converting arribados as total mature population later, if desired):

The figures speak for themselves. The species is clearly on the skids, and if present conditions continue it will shortly - in two years perhaps, or three, or five - be gone. The dramatic drop during the 1950's was caused by overexploitation combined with very heavy natural predation pressures. The terminal decline now in progress has been brought about by incidental trawler catch. When ridleys were many and shrimping was less intensive this factor was negligible. Today it is wiping out the species.

Lepidochelys kempi can possibly be saved, but it will surely disappear unless drastic action is taken. I hope therefore that the Survival Service Commission will be willing to write the new Mexican president, explaining the crisis and imploring him to take the only steps that could possibly save the Atlantic ridley from early extinction. I also hope you will solicit similar letters from other groups or individuals who might be willing to write. I enclose notes for the sort of letter that might be written.

Sincerely

Archie Carr,
Graduate Research Professor "

Model Letter

Address either of these officials: Estimado Dr. Carranza, or Lic. Rafful

I am writing to express profound concern over what appears to be the approaching extinction of a species of marine turtle, the Atlantic ridley, Lepidochelys kempi.

As you may know, L. kempi breeds only in the vicinity of Rancho Nuevo on the Gulf Coast of the State of Tamaulipas, about ninety miles north of Tampico. For some years your government has provided vigorous protection for the species on the nesting beach; but despite this attention, the decline has continued and stronger measures now are necessary. We respectfully urge that additional steps be taken to avert the impending loss of this species. The moves that appear particularly urgent are:

1. To designate the Rancho Nuevo shore, a 20-mile strip of beach extending north and south of Rancho Nuevo village, as a National Sanctuary to be kept wholly free of human exploitation.
2. To exclude all shrimp trawlers from a zone 10 miles seaward from that coastal strip during the months from April through July.

We want to emphasize that the Atlantic ridley is a distinct,strongly differentiated species, and not merely a local race or breeding colony of the wide-ranging Pacific ridley; and that except for occasional scattered nestings by individuals elsewhere, Rancho Nuevo is its sole breeding place. If L. kempi disappears from Rancho Nuevo it will almost certainly disappear from the face of the earth.

An important factor in the terminal decline the Atlantic ridley is undergoing is incidental catch in the nets of shrimp boats. You may be aware that strong efforts are now being made to perfect nets that will exclude turtles without hindering the capture of shrimp.

This is a severe technical problem, however. The equipment will probably not be perfected in time to save the Atlantic ridley. Thus, the fate of this unique and irreplaceable form of life is in the balance. Only a wholehearted effort by your government can save it. We beg you, therefore, to do all that you possibly can to exclude all human depredations at the nesting ground of the species and in adjacent inshore waters. You may be sure that everything possible will be done to insure protection of the ridley in the parts of its range outside Mexico, and that your intervention in this crisis will bring you the gratitude of people all over the world.

Sincerely yours