VVooc- grapi'.ic institution 



Foreword 



In July 1976, fishermen reported large numbers of dead surf clams and other 

 bottom-dwelling organisms in an 8,600-square-kilometer area of the New Jersey 

 continental shelf. The phenomenon continued through October of that year. Dur- 

 ing this period scientists from the National Oceanic and Atmospheric Administra- 

 tion (NOAA) expanded their routine surveys and monitoring in the region to 

 determine the extent of the problem and assess the damage to the fisheries. Other 

 researchers — from nearby States, universities, and private groups — joined in the 

 study. They determined that the mortalities were caused by extremely low con- 

 centrations of dissolved oxygen and by hydrogen sulfide poisoning in some bottom 

 waters. At the height of the event, dissolved oxygen values in the water were 

 measured at 2 milliliters per liter and sometimes at zero, in an area lying 10 to 100 

 kilometers off the 150 kilometers of coast between Sandy Hook and Cape May. 



Mortalities were greatest among surf clams, ocean quahogs, and other benthic 

 animals. Scientists estimated that by October 1976 more than half of the surf clam 

 population off the central New Jersey coast had died, and that a significant but 

 smaller number of ocean quahogs and sea scallops also died. Lobster catches 

 declined almost 50 percent during the period. As a result, in November the Federal 

 Government declared the New Jersey coast a resource disaster area. Estimates of 

 losses to commercial and recreational fishing industries, and related processing 

 and service businesses, were as high as $550 million. Local fishermen were also 

 concerned about the long-term impact of this event on their fisheries. 



This Professional Paper documents what we learned about resource and eco- 

 nomic losses caused by the decline in oxygen in these waters during the summer 

 of 1976. It also analyzes coastal oceanographic processes and conditions that af- 

 fected water quality during this period, especially departures from those conditions 

 that normally occur. Furthermore, this paper considers the possible role that human 

 activities near the affected region may have had in triggering the event. The effects 

 of adverse environmental factors on marine organisms are described as observed 

 in the field and studied in the laboratory. The volume brings together our knowl- 

 edge of the physicochemical makeup and ecology of these coastal waters. Finally, 

 the likelihood of future oxygen depletion events is discussed. 



The research during that summer improved our knowledge of environmental 

 changes in the region. The study indicates the importance of understanding and 

 continuing research into coastal oceanographic processes if we are to manage our 

 marine resources wisely in the future. 



/^UJJ^ 



James P. Walsh 

 Deputy Administrator 

 National Oceanic and Atmospheric 

 Administration 



111 



