DISCUSSION 



W 

 i n o 

 spec 

 for 

 from 

 quan 

 from 

 demo 

 maxi 

 note 

 at 1 

 over 

 both 

 over 

 rema 



M 

 spac 

 chem 

 & Gr 

 pred 

 spon 

 1973 

 that 



W 

 atta 

 1 eas 

 over 

 espe 

 (Ran 

 1 i m i 

 rese 



e pre 

 pen-r 

 i es r 

 space 



open 

 ti tat 



thes 

 spong 

 mum i 



that 

 20' . 

 whelm 



a hi 

 growt 

 in ob 

 echan 

 e are 

 i c a 1 s 

 een , 

 atory 

 ges f 

 ; Jac 



i n h i 

 hethe 

 eking 

 t i ne 

 growt 

 c i a 1 1 

 dall 

 t the 

 arch 



sent e v i 

 eef comm 

 i c h n e s s , 



that oc 

 -reef ha 

 i v e data 

 e commun 

 es appea 

 n our st 



coral c 



Neverth 

 s that o 

 g h diver 

 hs on co 

 scure at 

 isms by 



likely 

 Some 

 1974), a 



in n a t u 

 or aggre 

 kson & B 

 bits cor 

 r corals 



sponges 

 ff ecti ve 

 hs by sp 

 y by the 

 & Hartma 



i n f 1 u e n 

 is neede 



dene 

 unit 



but 

 curs 

 bi ta 



hav 

 i t i e 

 rs t 

 udy 

 over 

 el es 

 f co 

 sity 

 ral s 



thi 

 whi c 

 to i 

 spon 

 ltho 

 re ( 

 ss i v 

 uss , 

 al g 



the 



i s 

 ) be 

 onge 



ang 

 n, 1 

 ce o 

 d to 



e he 

 i es 



als 



in 

 ts ( 

 e be 

 s . 



o be 

 at 9 



inc 

 s, t 

 ral s 



of 

 , wh 

 s ti 

 h sp 

 nvol 

 ges 

 ugh 

 Baku 

 e gr 



197 

 rowt 

 msel 

 unce 

 caus 

 s at 

 elf i 

 968; 

 f ag 



tes 



re that 

 of the 

 o with 

 these e 

 R e i s w i g 

 en a v a i 

 Al thoug 



correl 

 0' and 

 reases 

 he tota 



at 90' 

 sponges 

 i 1 e all 

 me . 



onges c 

 ve rapi 

 are kno 

 these h 

 s, 1981 

 owth ov 

 5) , but 

 h been 

 ves use 

 r t a i n , 

 e of th 



depth, 

 shes Po 



H o u r i g 

 g r e s s i v 

 t this 



demosponges play an important role 

 Caribbean, not only in terms of 

 respect to the intense competition 

 nvironments. Demosponges are known 

 , 1973), but until now virtually no 

 Table on sponge/coral interactions 

 h the relative aggressiveness of 

 ated with depth, reaching a 

 120', it is interesting to 

 from a mean of 18.3% at 60' to 39.1% 

 1 species richness of sponges clearly 

 and 120'. The processes that permit 

 and a high frequency of aggressive 

 owing such a high % coral cover, 



an acq 

 d grow 

 wn to 

 ave ty 

 ). Th 

 er cor 



only 

 i d e n t i 



al lei 



but th 



e high 



Howe 



macant 



ui re 

 th r 

 poss 

 pi ca 

 e us 

 als 

 rece 

 fied 

 oche 

 i s s 

 f re 

 ver , 

 hus 



, ma 

 ates 

 ess 



ny 



e of 



has 



ntly 



(Su 

 mica 

 eems 

 quen 



pre 

 arcu 



inta 



and 

 vi ru 

 been 



all 

 been 



has 

 11 iv 

 Is t 



unl 

 cy o 

 dati 

 atus 



an , e_t 

 e spon 

 hypoth 



al_. 

 ges 

 esi s 



, in 

 on c 



pre 

 oral 



in and expand their 



/or al 1 el o- 



1 ent toxi ns ( Bakus 



considered anti- 

 el ochemical s by 



suspected (Bryan, 



a sponge toxin 

 an, e_fc aj., 1983). 

 o ward off 

 i k e 1 y (or at 

 f aggressi ve 

 on on sponges , 



and P_. paru 

 ) may help to 

 but further 



P- 



s , 



ACKNOWLEDGMENTS 



Special thanks go to M. W. Colgan and D. L. Green for assistance 

 in collecting field data at Salt River Canyon and to the personnel of 

 NULS-1 Hydrolab for their excellent operations program and unselfish 

 help during both missions. We also thank J. C. Ogden, D. K. Hubbard 

 and J. Bayes for help with various logistic and/or computer problems. 

 This study was funded by NOAA grants NA81AAA02690 , NA82AAA00470 , 

 NA82AAA00872 and NA82AAA01344 to T.H.S. and by funds from the West 

 Indies Laboratory. 



LITERATURE CITED 



Bakus, G. J. 1981. Chemical 



Reef, Australia. Science 

 Bakus, G. J. , & G. Green. 



a geographic pattern. 

 Benayahu , Y . , & Y . Loya . 



reef sessile organisms 



514-522. 



defense 

 211:497- 



mechan i sms 

 499. 



on 



the Great Barrier 



1974. Toxicity in sponges and hoi othurians ; 

 Science 185:951-953. 



1981. Competition for space among coral- 

 at Eilat, Red Sea. Bull. Mar. Sci. 31: 



59 



