Table 6. — Ranking comparisons of mean body lengths of all specimens of needlefish species examined with mean body lengths 

 of specimens with no copepods and specimens with a particxdar copepod (1~ smallest mean body length; S—largest mean 

 body length) 



Needlefishes with generalized copepods 



Needlefishes with specialized copepods 



Needlefish species 



All No Parabomo- 



specimens copepods lochus 



bellones 



Needlefish species 



All No 



specimens copepods 



Ablennes hians 



Belone belone 



Platybelone arpalus 



LhotskJa gavialoides. 



Strongylura anastomella 



Strong ylura 7uarina _ 



StTongylu ra notata 



StrongyluTa timucu 



Tylosurus acus 



Tylosurus crocodilua 



Total - ---- 



Ablennes hians 



Platybelo ne argalus 



StTongyhi ra eiilis 



StrongytuTa scapularis 



Tylosurus acus _,- 



Tylosurus crocodUus 



Total 



Strongylura ezUis 



Strongylura scapularis 



Total 



Ablennes hians _ . 



Platybelone argalus 



Tylosurus crocodUus 



Total 7.5 



4.5 



Strongylura exUis 



Strongylura marina 



Strongylura notata. 



Stronqylura scapularis 



Strongylura strongylura.. 

 Strongylura timucu 



Total 



Ablennes hians 



Strongylura anastomella. 



Strongylura leiura 



Strongylura strongylura.. 



Tylosurus acus 



Tylosurus crocodUus 



Total 



Ablennes hians 



Lhotskia gavialoides 



Tylosurus acus. 



Tylosurus crocodUus 



Total. 



Ablennes hians 



Strongylura marina 



Strongylura notata 



Strongylura thnucu. 



Tylosurus acus 



Tylosurus crocodilut 



Total. 



Lerman- 

 thropus 

 belones 



of the four specialized copepods inci-eases greatly 

 with the size of the needlefish. 



Competition Between Copepods 



Another question that we ask is: Does the 

 presence of one species of copepod interfere with 

 and thereby reduce the likelihood of infestation 

 with a second species of copepod? We examined 

 the relative numbers of individual needlefishes in- 

 fested by more than one species of cojiepod (table 

 7) and then considered the combinations of cope- 

 pod species (table 8) in the multiple-species 

 infestations. Some individuals of half the species 

 of needlefishes had two or more species of 

 copepods. Most of these are either large species of 

 needlefishes or species of which large numbers of 

 specimens were examined. As shown in the pre- 

 vious section, the likelihood of infestation of a host 

 by a specialized species of copepod increases with 

 the size of the host. And obviously, the more 

 specimens we examined, the more likely we were 



to find some individuals with more than one si>ecies 

 of copepod. 



The commonest combination of copepods (table 

 8) is Paraboniol-ochus helUnes and Lernanthropus 

 helones (65 of 308 records). These combinations 

 all come from the three western Atlantic species of 

 Strongylura., timucu (33), marina (21), and 

 notata (11), although both species of copepods 

 occur from the western Atlantic through the 

 western Pacific. Tlie reason for the absence of this 

 combination elsewhere is due to the lack of L. 

 belones in the eastern Atlantic and western Indian 

 Oceans which is caused by the scarcity of Strangy- 

 lura hosts in these areas. Also, P. bellones is rarer 

 in the Indian and Pacific Oceans where it is fre- 

 quently replaced by P. sinensis and the two species 

 of Notlwbomolochus. 



The next commonest combinations of copepods 

 involve Parabam-olochus bellones., Colobomatut 

 goodingi, Oaligodes laciniatm, and LemantJwopus 

 tylosuri: P. bellones and Colobomatus (37 rec- 



426 



U.S. FISH AND WILDLIFE SERVICE 



