numbers of gravid female black marlin occur in 

 the area (B. Goldman pers. obs.; J. Pepperell^). A 

 major sport fishery is based on this apparent 

 spawning migration and the catches are made 

 primarily just off the windward reef faces in the 

 northern Coral Sea. When sampling in November 

 1984, our research vessel was frequently operat- 

 ing in the midst of the sport fishing fleet. This 

 circumstantial evidence suggested the possibility 

 that the "non-pigmented" sailfish larva was in 

 fact the larva of the black marlin, and led us to 

 recheck these "non-pigmented" sailfish larvae. 

 Two specimens (5.6 and 9.7 mm) were cleared and 

 stained for bone and cartilage (Potthoff 1984); 

 both specimens had vertebral formulae of 

 11-1-13 = 24. This confirms that they are of the 

 genus Makaira (Nakamura 1985). These larvae 

 can be distinguished from those of the only other 

 Indo-Pacific member of the genus, the blue mar- 

 lin, by head profile and depth and minor pigment 

 differences. Therefore, we concluded that the 

 "non-pigmented" sailfish larva captured in the 

 present study were black marlin. A more detailed 

 treatment of the identity of "non-pigmented" sail- 

 fish larvae will be given separately (Ueyanagi 

 and Leis in prep.). 



The larvae identified here as sailfish are nor- 

 mally pigmented sailfish larvae which had not 

 previously been reported from the Coral Sea 

 (Ueyanagi 1974a, b). Only a few striped marlin 

 larvae were captured, and because nearly all 

 were small and only tentatively identified, they 

 are not considered further. 



Seasonal Occurrence 



Sailfish larvae were taken only in January, 

 February, and March. Blue marlin larvae were 

 taken in mid-November, January, February, 

 March, and April, although only one larva was 

 taken in April. Black marlin larvae were taken 

 throughout November, and three were taken in 

 January-February. 



A sequence of occurrence of larvae and pre- 

 sumably of spawning in the area begins with the 

 appearance of black marlin larvae in late spring- 

 early summer, followed by blue marlin in 

 summer-autumn, and finally sailfish in late 

 summer-early autumn. 



•*J. Pepperell, Fisheries Research Institute, N.S.W. Depart- 

 ment of Agriculture, Cronulla, N.S.W., Australia, pers. com- 

 mun. 1986. 



FISHERY BULLETIN: VOL. 85, NO. 4 



Horizontal Distribution 



Black marlin larvae were most concentrated in 

 block A adjacent to the seaward side of the reef on 

 all cruises (Table 1). Concentrations elsewhere 

 were low, with median values usually of zero. 

 However, data from only one cruise could be 

 tested statistically. The distribution of abun- 

 dance was similar to that of concentration, with 

 the exception that abundance in the two near-reef 

 blocks could not be shown to be significantly dif- 

 ferent during the first cruise. During the first two 

 (November) cruises, black marlin larvae were 

 taken in 7 of 8 samples from the near-reef area 

 (block A). Only three black marlin larvae were 

 taken on cruises three and four (January- 

 February), all in block A. Black marlin larvae 

 were present in only 13 of 96 samples taken else- 

 where, and of these areas, block B (0.25-1.0 nmi 

 offshore) had the highest frequency of occurrence, 

 5 of 24 samples. 



Clearly, black marlin larvae were consistently 

 found in greatest numbers closest to the seaward 

 side of the reef. The offshore extent of this high 

 density zone of black marlin larvae was very lim- 

 ited, extending at most to 1 nmi seaward (block B) 

 of the reef crest, but more likely to only 0.25 nmi. 



Blue marlin larvae were less abundant than 

 black marlin in our samples but had a similar 

 distributional pattern. Again, data from only one 

 cruise (the third) could be tested statistically. Ex- 

 cept for the second cruise, blue marlin larvae 

 were both most concentrated and abundant in 

 block A, the area closest to the seaward face of the 

 reef (Table 1). Further, 8 of the 13 occurrences 

 were in this block. During the second cruise, blue 

 marlin larvae seemed most concentrated and 

 abundant at block B (0.25-1.0 nmi off), but only 

 six larvae were captured on this cruise and only 

 two samples were taken in block A so the signifi- 

 cance of these results is questionable. Blue mar- 

 lin were, with the possible exception of the second 

 cruise, consistently found in greatest numbers 

 closest to the seaward side of the reef. This is 

 similar to the pattern for black marlin. However, 

 small numbers of blue marlin larvae were cap- 

 tured in block E, the most offshore segment of the 

 transect, and this offshore area had the second 

 highest frequency of occurrence of blue marlin 

 larvae (Table 1). 



Only 13 sailfish larvae were taken, and the 

 data are too sparse to indicate much more than all 

 but 1 of the 7 occurrences were in the two blocks 

 nearest the reef front (A and B). Sailfish larvae 



760 



