chapter 40 

 THE SEALAB II BIOLOGICAL PROGRAM 



A. O. Flechsig 



Scripps Institution of Oceanography 



University of California 



La Jolla, California 



The aim of the Scripps Institution of Oceanography biological program in Sealab II was to 

 describe the biological activity in, on, and just above the sea floor in the vicinity of the habitat 

 and as far away as the divers could operate with safety. The program was designed to de- 

 scribe the normal bottom fauna and to document any qualitative or quantitative changes that 

 took place after Sealab was placed on the bottom. To do this we needed: 



1. To determine the identities, abundances, and spatial distributions of the organisms at- 

 tracted to the Sealab site throughout the operation and to compare and contrast these with the 

 normal sandy-bottom and canyon faunas. 



2. To record the activities of organisms and their relationships with each other and with 

 the physical environment. This included studies of schooling, predator- prey relations, the 

 effects of light, etc. 



Our program required: 



1. That organisms be collected for identification and stomach analysis. 



2. That organisms be counted at diverse places and times to determine their abundances 

 and spatial and temporal distributions. 



3. That photographic observations be taken of the activities of organisms to study their 

 behavior and their relationships with the environment. 



To meet these requirements, the program was planned to use techniques and instruments 

 proven successful in shallow-water diving. In some cases there was anticipation of the need 

 for modification of these for the particular circumstances of the operation. There were also 

 several planned experiments. These included modification of the environment by construction 

 of block pyramids and behavioral studies in large wire- mesh holding cages. 



It was possible to carry out an extensive survey of the organisms present around Sealab, 

 although investigators were hampered by insufficient diving time. Available data indicate that 

 an object the size of Sealab provided with lights is a very effective fish attractant. By the end 

 of 44 days some 6,500 fish, representing 15 common species, were present. Over the entire 

 period a total of 47 species were observed. This is a much more rapid buildup of fish popula- 

 tions than has been observed at larger, shallower artificial reefs along the California coast, 

 presumably as a result of the presence of lights. Observations of predatory and other behav- 

 ioral interactions, and of patterns of distribution, coupled with studies of collected specimens, 

 have given a preliminary idea of the structure and dynamics of the community of animals, par- 

 ticularly fish, attracted to such artificial substrates. 



Following is a list of equipment and procedures intended for use during the Sealab II proj- 

 ect. Appended to each item is an estimate of its effectiveness and probable causes for inade- 

 quate performance. 



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