NSWC/WOL/TR 76-161 



juvenile and larval menhaden and blueback herring, averaging about 

 3.8 cm in length. These were killed out to a range of about 400 

 feet (122 meters) from surface zero. (In free water the shock wave 

 peak pressure level at 400 feet would be about 60 psi. This alone, 

 however, is not an adequate criterion for estimating the extent 

 of fish kill. 1 l ) 



It should be noted that the heavy plastic container of dye 

 did not rupture completely at the time of the explosion, and that 

 dye bled from the package for about two hours. This method proved 

 to be less satisfactory than the technique of placing a mixture 

 of dye and water in a paint can, which has been used successfully 

 in the past. 



3.3 Shot 2 



Shot 2 was planned as a fish monitoring experiment. A 9.1 

 kg Pentolite charge was exploded at a depth of 6.1 meters in 18.3 

 meters of water about 2.8 km upstream from the Solomons Facility. 

 However, only limited data were obtained because of the small fish- 

 kill. The kill was estimated visually to be less than 100 menhaden, 

 extending to a range of 350 feet (107 meters) from the explosion. 



Specimens of floating dead fish were collected from the boat 

 with a dip net up to 11 minutes after the shot. The data are 

 summarized in Table 3.2. The distances from surface zero are visual 

 estimates and are possibly in error by 25%. It is interesting to 

 note that no fish with damage levels (1) or (2) were collected. 

 Although injured, these would continue swimming and would remain 

 in the natural food chain. 



Two bottom trawls were attempted but they proved difficult 

 because of the 18.3-meter average water depth and the many 

 changes in depth encountered during the runs. The trawls were 

 run at least 45 meters from surface zero, and the trawl was first 

 placed in the water 19.5 minutes after the shot. This run started 

 2.25 minutes later, lasting a total of 5.12 minutes, while the 

 second run started 29.75 minutes after the shot, lasting a total 

 of 5 minutes. Only two anchovies about 5 cm long, were collected 

 in the trawl net. 



The results were inconclusive because of the deep water, the 

 distance from the location of the explosion, and the small number 



11. "Goertner, J. F. , 1977: Dynamical Model for Explosion Injury 

 to Fish, NSWC/WOL/TR 76-155, Naval Surface Weapons Center, 

 White Oak, Maryland. 



14 



