Research Product

The barge PECK SLIP broke up in the Pasaje de San Juan (P.R.) on 19 December 1978. Between 440-460,000 gallons of Bunker C were discharged into the open water as the barge was towed to Port Yabucoa. During the next few days, slicks came ashore between Punta San Agustin and Yabucoa, oiling approximately 26 km of shoreline. At request of the Scientific Support Coordinator, combined ecological/geological field studies of four environments (sand beaches-46 stations; gravel/cobble beaches-3 stations; mangroves-18 transects; and shallow lagoons and coral reefs-12 stations) were conducted between 22 December 1978 and 6 January 1979. A followup survey was conducted between 28 March and 4 April 1979 at selected sand beach and mangrove stations. At the sand beach sites, biological impact was observed in three subenvironments during the first few days of the spill: 1) supratidal beach grasses, 2) intertidal wrack (mortaliy of amphipods), and 3) subtidal grass beds. After three months, all areas had completely recovered except for the supratidal grasses, which were decimated in some areas (particularly Ipomea pes-caprae and Salicornia sp.). A number of snails (four species) and crabs (two species) died on heavily oiled gravel/cobble beaches. These areas were not revisted during the followup studies. Mangroves were by far the most sensitive environment to oil impact. Two acres of mangroves were heavily oiled (less than 20 cm oiling of prop roots) while 2.6 acres were lightly to moderately oiled. By the time of the followup survey, approximately one-half acre was defoliated. Crabs (Aratus pisonii), snails (Littorina), and epiphytes within the heavily oiled zone were greatly reduced in number. The shallow lagoons offshore of a heavily oiled, high wave-energy shoreline showed very light sheens within the bottom sediment; however, there was no visible impact on lagoonal flora of fauna, nor adjacent coral reef communities.