NSWC/WOL/TR 76-161 



include photography of the bottom, and, in some cases, divers with 

 biological training are used. However, areas where these species 

 are found are generally well known because of their commercial 

 importance, and these locations are avoided in explosive test 

 operations. 



For planning purposes, some forms of monitoring could be 

 pursued at a test site during a period when explosives are not 

 being detonated. For instance, a plankton net could be used to 

 check for the presence of eggs and fish larvae. This would 

 provide evidence of spawning. Another approach could be the 

 monitoring of water temperature for the occurrence of temperatures 

 that coincide with the initiation of spawning. For example, most 

 spawning of striped bass seems to begin at about 15.5 C. 



Post-Shot Evaluation 



It is most desirable to know the number, size, weight, and 

 species of the fish or other forms of marine life killed by an 

 explosion. In the past, this has been done by visual observation 

 of the floating dead fish. In cases where the fish kill was high, 

 the fish were netted and weighed. 



However, visual estimates are the least reliable and are 

 generally inconsistent because they include only the fish that can 

 be clearly seen floating at the surface. Visibility of floating 

 objects depends on the roughness of the surface, the depth of the 

 object, and the position of the observer. Also, an observer at a 

 distance usually can not estimate the weight reliably, and he 

 cannot always be sure of the species. If several species are 

 present, he must judge the relative numbers of each, which is 

 difficult even in ideal conditions. 



The accuracy is doubtless improved if at least two men in a 

 small boat can search the area and pick up all of the floating 

 fish. In this case, the fish can be sorted, measured and weighed, 

 if sufficient time is available. Specimens can be preserved for 

 later identification if necessary. Both methods, of course, do 

 not account for dead fish beneath the surface or on the bottom. 

 In addition, benthic organisms such as crabs and oysters are not 

 accounted for. 



When explosive charges are relatively large, it becomes 

 impractical to collect all of the dead fish, and a reliable 

 sampling technique is needed. The following has been proposed 

 by personnel of the Chesapeake Biological Laboratory at Solomons, 

 Maryland : 



5. Raney, E. C. , 1952: The Life History of the Striped Bass, 

 Bull. Bingham Oceanogr. Coll. Vol. 14, No. 1, pp. 5-97. 



