Surinam Ridleys At

Surinam Ridleys

at Sea

By DAVID K. CALDWELL,

WARREN F. RATHJEN

and BENNY C. C. HSU

- ~--- -- Beginning with the first issue, much has been said in the pages of the International Turtle and Tortoise Society Journal concern ing the biology of ridley sea turtles in the western North Atlantic. Rather surprisingly, Surinam Ridleys but legitimately so, the articles have dealt with both the Atlantic ridley (Lepidochelys kempi) and the so-called Indo-Pacific form WARREN F. RATHJEN (Lepidochelys olivacea) Although the ocean currents might well bring the two together somewhere off the associates did the same for the Atlantic rid Atlantic coast of North America, so far our ley in Mexico. However, like most articles data show the two species to be completely on sea turtles, their remarks were mostly separate in their geographical distribution. confined to studies On the nesting beaches. In the Western North Atlantic, L. kempi Because there is still so much to be learned sticks pretty much to the Gulf of Mexico and about ridleys, and all sea turtles for that the continental waters of the east coast of matter, we hope to provide some useful North America, but it has been taken in though fragmentary data by presenting the Bermuda. The other kind, L. olivacea, has following notes on a few ridleys taken in now been taken from as far north as Cuba fishing trawls at sea off the coast of Surinam. and Puerto Rico, but for the most part seems Not long ago the United Nations, through to confine its activities in this part of the the Food and Agriculture Organization of world to the northeastern coast of South the United Nations (FAO), instituted the America and immediately adjacent islands Caribbean Fisheries Development Project. and surrounding waters. For the most part, the initial phases of this In 1967, Peter Pritchard provided a fine program have been devoted to exploratory article in these pages on the Indo-Pacific fishing in the West Indies, Caribbean and ridley and its nesting activities in Guyanas off the northern and northeastern coasts of (still known to most of us as British Gui South America. The work ha" complemented ana), and in 1968, Humberto Chavez and his the exploratory fi"hing efforts of our own

• Research vessel Call1mr/.1·, used by United Nations Caribbean Fisheries Development Project, captured many ridleys off the coast of northeastern South America. They were later returned to the sea after thorough study by biologists. Most specimens taken were adults. Research vessels of this program helped to provide much additional data on the habits of the ridley.

I . •

.~ 1 .. ." . . I r Dr. Caldwell is Director of the Marineland Re search laboratory, St. Augustine, Florida. Mr. Rathjen is Chief of Exploratory Fishing for the United Nations Caribbean Fisheries Development By DAvrD K. CALDWELL, Project with headquarters in Barbados, and Mr. at Sea Hsu is a member of the latter group. and BE NY C. C. HSU

Bureau of Commercial Fisheries R/V Ore All of the Indo-Pacific ridley turtles taken gon. The ultimate aim of all of this work is by the F AO vessels at sea in this manner to try to improve the lot of the protein so far have been adult in size according to starved people of the region through proper Pritchard's data on nesting females. The re management and exploitation of their nat lated notes that have been accumulated from ural sea resources. them during their brief stays aboard the Usually quite accidentally, the vessels of R/V Calamar are: the FAO program have taken a number of 1. A female measuring 70 cm in carapace ridleys in their bottom fish trawls. The length and 60 cm in carapace width, was Oregon, too, has been credited with at least taken at Calamar station 219 on 31 October one capture. Unfortunately, being air breat.h 1967 at 6° 15' N, 54° 45' W in a trawl fish ers, many such unseen captives drown in the ing on the bottom inshore off Surinam at a nets before they are hauled in, but even so depth of 10 to 12 fathoms. Half of the right they provide food for the crew and food for foreflipper of the turtle was missing, but it thought for the biologist. On the other hand appeared healthy and, like most turtles with some of the ridleys make it to the deck of (turn to p. 23) the vessel alive, and after suffering some harmless indignities like being measured, weighed and tagged, are returned to the water to go about their reptilian business. • Lf'pidochelys olivacea specimen is examined by personnel aboard the Calmnco'. Many specimens were taken in fishing nets, tagged. • Carapace of an Indo-Pacific ridley from Suri nam, displayed by biologist. Laminae have bee~ outlined in white. Data show two ridley species seem to be separate in distribution.

. ------such a loss, did not seem to be especially 5. Prior to the capture of the specimen bothered by it. There were 7 laminae on each off Surinam in October, 1967, about 10 rid side of the carapace. This turtle drowned, leys were taken by trawl in the same region and when opened reportedly contained over from summer and early fall, 1967. Although 200 ovarian eggs, each about 5 mm in diam detailed records of the captures were not eter. The digestive tract contained 2 small kept, from the locality of capture it seems fresh unidentified catfish each about 9 cm almost certain that at least some of these in length, 10 small unidentified and broken were involved in nesting in Surinam. A pho snail shells, three small unidentified crab tograph of the carapace of one of this group carapaces, about two liters of yellow-green showed a 7-7 laminae count. ~~' slimy liquid (jellyfish remains, it was pos It should be especially noted t . . of tulated) and some sand and mud massed these turtles were takE'n in the fi ,while near the anus. The turtle was not saved, but nesting in the region occurs in the summer the record is substantiated by photographs according to Pritchard and to Carr. One of and drawings. the ridleys of this species taken in the 2. On 17 August 1968, a female, measur Greater Antilles, from Puerto Rico, was also ing 66 cm in carapace length and 60 cm in captured in the fall. This suggests either a carapace width, was drowned in a trawl fish resident population of Indo-Pacific ridleys ing at a depth of 8% fathoms at Calamar off northeastern South America and in the station 516 at 6° 19' N, 54° 48' W. The turtle Antilles, a constant recruitment from Africa contained 2 shelled eggs each 45 mm in di via the North or South Equatorial Currents, ameter (it was felt that others might have or a movement by the turtles not totally at been lost as she struggled in the net) and a the will of the current flow since a turtle large number of smaller ovarian eggs rang merely riding the current would be swept ing in size from 2 to 20 mm. There were 7 far beyond Surinam, and Puerto Rico, by laminae on each side of the carapace, but the October after a late summer nesting season. distinction was poor between the fourth and fifth on each side. Unlike most larger ex amples of a given species of sea turtle taken at sea, this individual carried no barnacles. 3. On 6 September 1968, two ridleys were taken by the Calamar at stations 535 and A.~ REFERENCES ~... ,. 536 in the same region. One of these was a ADAMS, DEARL E., 1966. More . e ridley female, bearing ovarian eggs, that measured operation: Padre Island egg tr . g. Int. Turtle and Tortoise Soc. J .• 1 (• , 40-43. 83 cm in carapace length and weighed about 45. . . "". CALDWELL, DAVID K., 1966. A nesting report . 30 kg. The other was a male measuring 100 on the American ridley sea turtle nesting (genus LepidocheIY8). Int. Turtle and Tortoise cm carapace length weighing about 35 kg. Soc. J., 1 (l): 10-13, 30. 48. CARR, ARCHIE, 1967. So excellent a fishe. The 4. Two other ridleys, both males, were Natural History Press, Garden City, N.Y. taken nearby at Calamar station 553 on 9 CHAVEZ, HUMBERTO, MARTIN CONTRERAS G. and T. P. EDUARDO HERNANDEZ D., September 1968. One, measuring 94 cm in 1968. On the coast of Tamaulipas. Part 1. Int. Turtle and Tortoise Soc. J., 2 (4): 20-29, 37; carapace length, weighed 34 kg; the other, Part 2. Int. Turtle and Tortoise Soe. J., 2 (5): 16-19, 27-34. measuring 100 cm in carapace length, weigh PRITCHARD, PETER C. H., 1966. Sea turtles of Shell Beach, British Guiana. Copeia, (l): 123 ed approximately 35 kg. The first drowned 125. --, 1967. To find the ridley. Int. Turtle and in the net, but the second was tagged with Tortoise Soc. J., 1 (4): 30-35, 48. a i';hark tag and released.

. .- .