NOTE Caillouet et al.: Sea turtle strandings and shrimp fishing effort in northwestern Gulf of Mexico 



717 



Hopkins-Murphy 1989, Shoop and Ruckdeschel 1989, 

 Whistler 1989). In the northwestern Gulf, tidal currents 

 move water toward shore, and waves and surface drift 

 transport floating objects to the beach from longshore 

 currents (Collard 1990, Collard and Ogren 1990). Swim- 

 ming and diving abilities may be reduced in stressed 

 or injured sea turtles, causing them to remain at or 

 near the surface while being transported more or less 

 passively. The longer a carcass remains in the water, 

 the longer it would be subjected both to decomposition 

 and scavengers which could cause it to disarticulate, 

 release bloating gases, and sink. Not all turtles that 

 become stranded are documented by the STSSN. Thus, 

 reported strandings of sea turtles provide an incom- 

 plete measure of those that are killed or injured by 

 humans or that succumb to natural mortality factors 

 at sea (Murphy and Hopkins-Murphy 1989). 



On the upper coast, significant correlations were 

 observed in 0-15 fm where 71% of the shrimp fishing 

 effort on the upper coast occurred during 1986-89 

 (Table 2, Fig. 2). Significant correlations were observed 

 on the lower coast in 5-15fm where 33% of the lower 

 coast effort occurred. Such correlations suggest that 

 the impact of shrimping on sea turtles may occur within 

 15 fm seaward of the coastline, and this is consistent 

 with the conclusion by Magnuson et al. (1990) that in- 

 cidental capture of sea turtles in shrimp trawls occurs 

 for the most part in depths up to 27 m (15 fm). However, 

 on the lower coast 5% of the shrimp fishing effort oc- 

 curred in the 0-5 fm interval, and we observed no 

 significant correlation for that interval. 



It is neither practical nor cost-effective to attempt 

 characterization of all conditions and factors that in- 

 fluence whether sea turtles become stranded and where 

 and when they become stranded in relation to various 

 causes of mortality, injury, stress, or illness at sea. 

 However, year-round coverage is essential to monitor- 

 ing temporal variations, and it provides biological 

 samples, specimens for necropsy, and other informa- 

 tion that can be compared with human activities and 

 oceanographic variables in examining the causes of 

 strandings. 



Acknowledgments 



Special thanks are due all who participated in docu- 

 menting sea turtle strandings in southwestern Loui- 

 siana and Texas. Sea turtle stranding data were pro- 

 vided from the STSSN database by Dr. Nancy Thomp- 

 son and Wendy Teas, NMFS Miami Laboratory, Miami, 

 Florida. Shrimp-fishing effort data were provided by 

 Frank Patella, NMFS Galveston Laboratory, Galves- 

 ton, Texas. 



Drs. Edward Klima, Terry Henwood, Nat Frazer, 

 James Nance, Larry Ogren, and Tom Minello as well 

 as Anthony Amos, Clark Fontaine, Sally Hopkins- 

 Murphy, Sharon Manzella, and Zoula Zein-Eldin 

 reviewed the manuscript and provided helpful com- 

 ments. The United States Army Corps of Engineers, 

 Galveston District, Galveston, Texas, provided over- 

 water transportation to west Matagorda Peninsula. 

 Texas Parks and Wildlife Department provided over- 

 water transportation to Matagorda I. Reconnaissance 

 flights were made possible by the U.S. Coast Guard, 

 Perry R. Bass, San Jose Island Cattle Company, and 

 Major Donald C. Meek. Robert Caplinger typed the 

 manuscript. Jo Anne Williams and Sharon Manzella 

 prepared the figures. 



Citations 



Amos, A.F. 



1989 Recent strandings of sea turtles, cetaceans and birds in 

 the vicinity of Mustang Island, Texas. In Caillouet, C.W. Jr., 

 and A.M. Landry Jr. (eds.), Proceedings, First international 

 symposium on Kemp's Ridley sea turtle biology, conservation 

 and management, p. 51. TAMU-SG-89-105 (abstr. only), 

 Texas A&M Univ. Sea Grant Coll. Prog., College Station. 



Booker, W.C., and L.M. Ehrhart 



1989 Aerial surveys of marine turtle carcasses in National 

 Marine Fisheries Service statistical zones 28 and 29; 11 August 

 1987 to 31 December 1988. In Eckert, S.A., K.L. Eckert, and 

 T.H. Richardson (compilers), Proceedings, Ninth annual 

 workshop on sea turtle conservation and biology, p. 15-17. 

 NOAA Tech. Memo. NMFS-SEFC-232, Southeast Fish. Sci. 

 Cent., Miami. 



Collard, S.B. 



1990 Guest editorial: Speculation on the distribution of 

 oceanic-stage sea turtles, with emphasis on Kemp's Ridley 

 in the Gulf of Mexico. Marine Turtle Newsl. 48:6-8. 



Collard, S.B., and L.H. Ogren 



1990 Dispersal scenarios for pelagic post-hatchling sea turtles. 

 Bull. Mar. Sci. 47(1):464-491. 

 Fontaine, C.T., S.A. Manzella, T.D. Williams, R.M. Harris, and 

 W.J. Browning 



1989 Distribution, growth and survival of head started, tagged 

 and released Kemp's Ridley sea turtles (Lepidochelys kempi) 

 from year-classes 1978-1983. In Caillouet, C.W. Jr., and A.M. 

 Landry Jr. (eds.), Proceedings, First international symposium 

 on Kemp's Ridley sea turtle biology, conservation and manage- 

 ment, p. 124-144. TAMU-SG-89-105, Texas A&M Univ. Sea 

 Grant Coll. Prog., College Station. 

 Fritts, T.H., A.B. Irvine, R.D. Jennings, L.A. Collum. 

 W. Hoffman, and M.A. McGehee 



1983 Turtles, birds, and mammals in the northern Gulf of Mex- 

 ico and nearby Atlantic waters. U.S. Fish Wildl. Serv. FWS/ 

 OBS-82/65, 455 p. 

 Heinly, R.W., E.K. Stabenau, A.M. Landry, and M. Duronslet 

 1988 Mutilation of stranded sea turtles along the Texas coast. 

 In Schroeder, B.A. (compiler), Proceedings, Eighth annual 

 workshop on sea turtle conservation and biology, p. 33-34. 

 NOAA Tech. Memo. NMFS-SEFC-214, Southeast Fish. Sci. 

 Cent., Miami. 



