Increased numbers of sea turtle strandings on the Gulf of Mexico beaches in recent years have led to questions regarding the causes of elevated mortalities with attention to natural population cycles, as well as impacts relating to human activities (exposure to platform salvage operations, exposure to pollution from industries that use oil and coal, ingestion of nonbiodegradable debris, and entrapment in fishing nets). Stranded marine turtles recovered during the NMFS stranding surveys of beaches, as well as those retrieved by the Texas Marine Mammal Stranding Network are necropsied to develop protocols of identifying cause of death. Necropsy procedures include: 1) characterizing ingestion of non-biodegradable material; 2) anatomic inspection for man-related trauma; and 3) histopathologic, microbiologic and toxicologic analyses of selected tissues.

Texas is the site of two major industries--shrimp and oil--whose operations are perceived in conflict with sea turtle stocks. Texas annually leads all Gulf states in total number of stranded sea turtles as well as Kemp's Ridley strandings. The number of Kemp's Ridley turtles found on Texas beaches during 1985 totaled 64 while 175 were found stranded during the first half of 1986 (Jan 1-Aug 1). During a two-year period (Aug 1, 1984-Aug 1, 1986) a total of 559 marine turtles were stranded, including Kemp's Ridley (278) the loggerhead (233), the green (25), the hawksbill (15), and the leatherback (8).

Preliminary totals of sea turtle strandings for Texas and southwest Louisiana reported to the southeast region of the Sea Turtle Stranding and Salvage Network (STSSN), headquartered in Miami, FL, were 273 in 1986; 220 in 1987; and 186 in 1988. Loggerhead and Kemp's Ridley accounted for the largest number of strandings in 1988: loggerhead-102; Kemp's Ridley-51; green-6; hawksbill-7; leatherback-8; and unknown-12.

Data generated by STSSN surveys and necropsies have shown trends relevant to describing mortalities among sea turtles. The critically endangered Kemp's Ridley (162 individuals-44.5%) and loggerhead (128 individuals-35.2%) have accounted for nearly 80% of the 364 turtles collected by Dr. Landry's graduate students working as NMFS/STSSN surveyors along the southwestern Louisiana and upper and middle Texas costs since 1986. Peak stranding rate over this three year period consistently occurred during March through May. Human-inflicted mutilation (severed head and/or appendages, bullet wounds, etc.) rate for 153 turtles examined since 1986 have annually ranged from 16 to 49%. Food habit analyses, in addition to producing useful information on natural dietary preferences, have shown that over 33% of the 117 stomachs examined to-date contained man-made debris in the form of plastics, rubber, wood, etc. These preliminary data along with current and ongoing necropsies will be pertinent to assessing the magnitude and source of mortalities in sea turtles.