found with P. hellones, P. sincnJih, Nothobonw- 

 lochu.3 gibber, or N. d/glfatus, which are found 

 only outside the eastern Pacific. 



The rarity of some combinations may be related 

 to competition between species of cope|)ods. For 

 example, we found no records of Parabomol'Ochus 

 beUones with Nothobomolochxis gibber, only one 

 record of P. belloneH witli N . digitatus, and none 

 of N. gibber with N. digitatus. The geographical 

 distributions of these three species overlap 

 broadly, and they live in similar ecological niclie-s 

 on needlefish. On the basis of this lack of co- 

 occurrence and on the greater abundance of Notlio- 

 bomoloclius from the eastern Indian Ocean to the 

 central Pacific, we believe Nothobmnolochus ( and 

 P. sinensis) may liave evoh'ed more recently and 

 may be in the process of replacing P. bellones in 

 the above areas. 



Evidence also exists of competition between the 

 two eastern Pacific species of Parabomolochii^. 

 P. ensiculus is usually found in the mouth, under 

 the oral valves; P. con-strictiis is usually found 

 under the opercles. There are only three records of 

 co-occurrence on a sjiecimen of needlefish. In at 

 least one of these, two P. constrictus were under 

 the ojjercles and one P. ensiculus was under the 

 oral valves. 



In this study, no two species of ergasilid cope- 

 pods were taken from the same host individual 

 although two ergasilids, ErgasiJus spatidus and 

 Aeimcola tenax, were taken from what is now 

 considered one species of needlefisli, Strongylura 

 marina, at different localities. Ergasilids are gen- 

 erally fresh-water copepods and other needlefish 

 copepods are marine ; it would be surprising, then, 

 to find an ergasilid on the same host individual 

 with a marine copepod. We found two such 

 records, however, E. infatipes and Parahomolo- 

 cJius beUones on a specimen of S. senegalensis from 

 Ebzie Lagoon, Ivory Coast, and E. coleus and 

 Nothobomolochus digitatus from S. strongylura 

 from Sandakan Bay, Borneo. 



We have shown that larger needlefishes are more 

 likely to have specialized copepods than smaller 

 needlefishes. Do they also have more species of 

 copepods? Seven species of needlefishes had more 

 than two species of copepods on the same individ- 

 ual host (table 7). A total of only nine specimens 

 represented the four species of Strongylura with 

 individuals having more than two species of cope- 



pods (three each) : one S. leiura with Caligodes, 

 L. tylosuri, and N. digitatu.s; three S. notata, and 

 four S. tirmicu with Colobomatus, L. belones, and 

 P. bellones; and one S. strongylura with P. sinen- 

 sis, N. digitatus, and L. tylosuri. The other cases 

 of more than two species of copepod on the same 

 host individual are indeed in the three large 

 worldwide species: Ablennes limns, Tylosunis 

 acus, and T. crocodilus. One specimen of T. acus 

 had three species of copepods, two specimens had 

 four; eight specimens of T. crocodilus had three 

 species; three specimens of Ablennes had three 

 species, three had four species, and two specimens 

 liad five. Seven species of copepods were involved 

 in the 19 multiple combinations: L. tylosuri (17) ; 

 Colobonmtns (15) ; Caligodes (13) ; Oaligus spp. 

 (8) ; P. bellones (6) ; P. constrictus (4) ; and N. 

 digitatus (1). 



The two specimens of Ablennes with five species 

 of copepods were both from the Gulf of Guinea: 

 a 418-mm. BL specimen with 2 female Caligodes, 

 2 female L. tylosuri, 6 female P. beUanes, 3 female 

 CaJigus sp. A, and 1 female Colobomatus; and a 

 530-mm. BL specimen with 25 female Caligodes, 

 1 male L. tylosuri, 3 female P. bellones, 1 male 

 and 1 female Caligus sp. A, and 3 female 

 Colobomatus. 



The three T. acus specimens were 316, 374, and 

 535 mm. BL ; the eight T. crocodilus 203, 227, 236, 

 261, 268, 300, 320, and 388 mm. BL; and the eight 

 Ablennes 418, 455, 462, 483, 490, 508, 530, and 540 

 mm. BL. The species means (408, 275, 486) are 

 greater than the mean body lengths of uninfested 

 specimens, of all specimens examined (347, 250, 

 306), and of specimens infested by any particular 

 species of copepod except the mean body length 

 of T. crocodilus infested with Caligodes — 303 mm. 

 Thus, although the multiple-infest«d needlefishes 

 are not the largest specimens of their species, they 

 are larger than other grou2:)ings of their species. 



Variation in Infestation With Time and Space 



We have relatively few data on changes with 

 time in infestation in a given population of needle- 

 fish. The best data come from the infestation by 

 Colobonyttus goodingi of three Bahamian samples 

 of Strongylura notata taken in 1927, 1935, and 

 1963 (table 9). Four of six specimens from 

 Crooked Island taken in 1927 were infested. Ten 

 of 12 specimens collected at Bimini in 1935 were 



428 



U.S. FISH AND WILDLIFE SERVICE 



