Additional cruises of the Endeavor took place on January 26-29, February 

 8-12, and February 21-25, 1977. These cruises were designed to further 

 delineate the amount of oil in the water column and in the sediments, as well 

 as to continue the assessment of oil impact on the biology of the affected 

 area. Reports on all four Endeavor cruises are contained in Appendix V. 



The NMFS and URI are now beginning both an extensive sampling program 

 and laboratory studies of fish, shellfish, and plankton populations that may 

 have been damaged by the Argo Merchant spill. Twelve to 18 months will be 

 required to complete the study and sort out the complex interactions among 

 the levels of fishing mortality, natural mortality, oil mortality, and the 

 sublethal effects of oil on the productive potential of fish resources. A 

 short-term study based on the analysis of the results of three surveys of the 

 spill area, laboratory observations, and an account of interviews with fisher- 

 men is underway. A brief summary of NMFS and URI studies is given below, 

 including preliminary results. 



4.1.1 Zooplankton Studies 



The material in this section was contributed by R. Maurer of NMFS, NEFC, 

 Narragansett, Rhode Island, and is based on samples collected during the 

 first cruise of the Delaware II(T)E 76-13) . 



A full array of plankton samples was taken at Stations 4 through 9 on 

 the first Delaware II cruise (Figure 4-1 and Table 4-1). Standard oblique 

 tows were made concurrently with large 61-centimeter bongos (0.505- and 

 0.333-millimeter mesh nets) and small 20-centimeter bongos (0.253- and 0.165- 

 millimeter mesh nets) , quantitatively integrating the water column from near 

 the bottom to surface. In addition, 10-minute surface tows were made with a 

 1-by 1/2-meter neuston net (0.505-millimeter mesh net). Samples from the 

 oblique tows (0.333-millimeter mesh net) were analyzed by the Plankton Sort- 

 ing Center (NEFC, Narragansett) to provide information on plankton biomass, 

 abundance, and diversity. Results from this analysis are presented in Table 

 4-2 and Table VII-15 in Appendix VII. 



The dominant copepod species from each station were cleared (rendered 

 transparent) with lactic acid and examined under a dissecting scope for the 

 presence of oil. On the basis of a preliminary examination the contamination 

 was classified as (1) external smudges on the exoskeleton; (2) mandibular 

 particles adhering to feeding appendages or tar stains on mandibles (Figure 

 4-3) ; and (3) oil particles that had been ingested and were either stored or 

 present in the gut, and/or incorporated in feces (Figure 4-4). 



Zooplankton biomass ranged from 2.0 to 16.4 cc/100 m^ (Table 4-1). The 

 lowest biomass measured was within the oil slick area at Station 7, while the 

 highest values were recorded at inshore Stations 4 and 9. Zooplankton num- 

 bers follow trends in biomass. Extremely high numbers and biomass occurred 

 at Station 9, which was located on the boundary of the visible slick. 



Zooplankton species abundance is shown in Table VII-15 in Appendix VII. 

 Life stages indicate a separation of the more dominant forms into size cate- 

 gories of large, medium and small. 



94 



