4 OKHAMANDAL MARINE ZOOLOGY REPORT 



Arab divers been employed. My experience is that, if anything, Arabs are more 

 sensitive to cold than Tamils. In the Persian Gulf, for instance, no diving for pearl 

 oysters goes on during the winter months — those during which we worked at 

 Okhamandal — work being confined to the hot summer months of June to September ; 

 the two intensely hot months of July and August are considered the best and constitute 

 the height of their season. 



In consequence, while the results obtained are sufficient to enable me to 

 pronounce definitely upon most matters which I set out to examine, it must be 

 remembered that the investigation has not been exhaustive. Five weeks' work in 

 marine biology, carried out single-handed, is inadequate to do more than clear away 

 initial difficulties and misconceptions, and to show the most suitable lines for the more 

 detailed investigations of my successors. It has been good pioneering, and just 

 sufficiently ample to enable the economic potentialities of the locality to be assessed 

 for some of the most likely organisms. 



The collections made of marine animals and plants are large and important for 

 many groups. Sponges, coelenterates (especially hydroids and alcyonarians), crustaceans, 

 worms and algse are notably well represented. The plankton (minute free-swimming 

 life of the sea) I could wish to comprise a larger number of samples, but the material 

 will be found ample, I believe, to enable an approximate census to be made both of the 

 relative and the absolute proportions present in the Okha waters of the chief organisms 

 which contribute to the dietary of the two forms of pearl oysters found in this locality. 



These collections have now been sorted and have been placed in the hands 

 of specialists to be reported upon in detail. 



It may be well to point out here that the examination and identification of the 

 hosts of animals and plants comprising the marine fauna and flora of the Gulf of Kutch 

 have much more than an academic and purely scientific interest. Within the assemblage 

 are comprised enemies of the pearl oysters — sponges, corals, starfishes, worms, fishes — 

 some that burrow into and destroy the commercial value of the shell, others that 

 kill oysters directly and yet others that compete for food and space and foothold 

 with the oyster, and which, if excessively numerous, may entail starvation on the 

 mollusc and even elbow it out of existence locally. The comparative abundance 

 of seaweeds is a factor of great moment, for their spores at certain seasons constitute 

 a great proportion of the food of oysters, while the rankness of their growth, as 

 I can testify, so masks and hides the presence of oysters that pearl-fishing in 

 December and January is impossible in practice. It is matter for regret that I 

 cannot see the same localities in June or July when, I believe, this extraordinary 

 growth of weeds dies down annually. 



Nature does not always hold an even balance ; it dips occasionally and only an 

 intimate acquaintance with the bionomics of the whole assemblage of the local fauna 

 can enable us to devise eff"ective cultural measures and to guard those deposits of 



