STRUHSAKER and MONCRIEF: BOTHUS THOMPSONI 



specimens). Bothus thonipsoi/i has 10-14 

 pectoral rays, whereas this count is 9-11 for 

 both B. paiitlieri)tns and B. niaiictts. 



With regard to other Indo-Pacific species 

 recognized by Norman (1934), B. thompsoni 

 differs from B. nnjriaster in that the pectoral 

 fins of males are not elongated in the former 

 species. The combination of cycloid and ctenoid 

 scales on the ocular side of B. thonipsoni dif- 

 ferentiates it from B. assimilis (Giinther) which 

 has onl}^ cycloid scales and from B. leopardinus 

 (Giinther) which has only ctenoid scales on the 

 ocular side (Norman. 1934). Norman (1934) 

 considers also that B. coiisteUatns (Jordan, 

 ill Jordan and Goss) is very doubtfully distinct 

 from B. leoparduius. 



Although no illustration was given of B. 

 budkeri (Chabanaud. 1942) from the Red Sea, 

 it differs from B. fhotiipi<(>)ii in having a lesser 

 body depth, fewer dorsal and anal rays, fewer 

 gill rakers on the lower limb of the first arch, and 

 only ctenoid scales on the ocular side. 



Fowler (1933) described five species of Bothus 

 from the Phili])pines and China Sea. The 

 generic placement of several of these species is 

 questionable. At any rate, none of them could 

 be confused with B. thoinp.^oiii. 



Ecology 



With the exception of one specimen caught at 

 a depth of 72 m off Maui, all specimens of 

 B. thompsoiii taken to date have come from 

 depths of 90-113 m off the north coast of Oahu 

 where bottom temperatures ranged from 24.5° 

 to 26.0°C. About 580 specimens (32-107 mm 

 SL) have been obtained at 13 stations where 

 catches ranged up to 275 individuals per haul. 

 An analysis of dispersion for this species 

 (Struhsaker. 1973) shows it to have a highly 

 clumped distribution. The type of bottom in the 

 area of capture is primarily muddy sand 

 interspersed with patches of sponge, broken 

 shell, and rubble. Bothus thompsoni was often 

 taken with 20-30 other species of fishes; it 

 usually comprised less than 8% of the total 

 catch, but occasionally ranged up to 30%. Nu- 

 merically dominant species taken with B. thomp- 

 soni include Tmchiiiocephaliis niyops, Priacaii- 

 thus spp., Aiitigoiiia cos. Parupeneus chyysoiie- 

 mus, and Lagocephalus hypselogeueioii. Struh- 



saker and Higgins (rnanuscr.-) have shown 

 that B. thompsoni is the third most abundant 

 larval flatfish (after Engyprosopo)i .ve)icuidrus 

 Gilbert and B. paiitlierinus) taken in offshore 

 mid water hauls near Oahu. They also presented 

 evidence that B. thompsoni may spawn through- 

 out the vear. 



ACKNOWLEDGMENTS 



We thank John E. Randall for the photo- 

 graphs used in Figures 1 and 2 and for review- 

 ing the manuscript. We are also indebted to 

 Elbert H. Ahlstrom and C. Richard Robins 

 for comments on the manuscript. The NMFS 

 Systematics Laboratory provided the radio- 

 graphs. The illustrations are by Tamotsu 

 Nakata and Robert Bonifacio. 



MATERIAL EXAMINED 



USNM 208494: TC-33-52 (R/V Towusend 

 Ci'omwell, cruise 33, station 52); 1 male (109.2 

 mm SL); lat. 19°58.3' N, long. 156°28.5' W; 

 depth 72 m, 13 Nov. 1967. USNM 208495: 

 TC-36-15; 4 females (93.7-99.1 mm SL); lat. 

 21°37.7' N, long. 158°08.8' W; depth 113 m. 

 2 May 1968. USNM 208496: TC-36-20; 7 

 females (39.5-72.8 mm SL), 12 males (55.8- 

 81.2 mm SL); lat. 21°36.8' N, long. 158° 12.5' 

 W; depth 110 m, 3 May 1968. USNM 208497: 

 TC-40-115; 10 females (56.9-87.3 mm SL), 

 5 males (70.0-84.5 mm SL); lat. 21°36.8' N, 

 long. 158° 08.2' W; depth 102 m, 8 Nov. 1968. 

 USNM 208498: TC-40-116; 4 females (56.0- 

 105.4 mm SL), 3 males (58.6-104.5 mm SL); 

 lat. 21°36.8' N, long. 158° 11.6' W; depth 112 

 m. 1 Dec. 1968. USNM 208499: TC-40-119; 

 5 females (78.6-91.2 mm SL), 7 males (86.2- 

 99.2 mm SL); lat. 2r36.8' N, long. 158° 11.2' 

 W; depth 96 m, 1 Dec. 1968. BPBM 14102; 

 TC-40-125; 1 female (106.4 mm SL), 1 male 

 (114.4 mm SL); lat. 21°36.8' N, long. 158°11.6' 

 W; depth 102 m, 10 Nov. 1968. 



- Struhsaker. P., and B. E. Higgins. Unpubl. manuscr. 

 Post-larval flatfishes (Pisces:Pleuronectiformes): Observa- 

 tions on the identity and ecology of 11 Hawaiian species. 

 Southwest Fisheries Center. National Marine Fisheries 

 Service. NOAA, Honolulu. Hawaii 968 12. 



245 



