Table 1. — Length, life stage, and seasonal occurrence of species 

 coUictcd beneath flotsain in the offshore traters of Central 

 America^ in 1963 



Species 



Lobotidao (triplolails") 

 Lohotes pacific us (Jilbert- 



Caranpidac (j;icks and scads) 

 Cnrani cahnUtis CJiinther, . 

 Carani hippna (Linnaeus). 

 CarauT marijinatus (Gill)-. 



Jiecapfenix sp.3.. 



F.laijnfis hipiunulatus 



(Qiioy and Gaimard) 



NaJicrtilfn diictor 



(Linnaeus) 



Sfifir crujneftopkfhalmus 



(Blocl))... 



Seriola cofhnnii 



(Evermann and Clark).. 

 Seriola sp 



Corypliaenidac (dolphins) 

 CoTijphaena equiselia 



Linnaeus 



Corijphaena hippurns 



Liiniaeus_ 



Mullidae (poatfislies) 

 Psfudiipeiiens 

 grandisfiuamis (Gill) 



Kypliosidac (scii chubs) 

 K'/jifiostis nniilogn.t (Gill) 

 K'Ji'hns/is dftiinm (Peters) 



h'lj ;»ft OS » .s s p , '1 



Sectnfitr ori/iirns 

 (Jordan and Gilbert)... 



Pomacentridae 

 (daniselfishrs) 

 Ahudtfdu f sarntilis 



(Linnaeus) 



CtiTomis atrilohata Gill 



Scombridae (mackerels and 

 tunas) 

 Aiiris fharard (Lac^pede). 

 Euthtinnns lineatus 



Kishinouye 



Kafxiiannii.t vdamis 



(Linnaeus) 



Thuunti.K filhacares 



(lionnaterre) .- _, 



BIcnniidae (combtooth 



blennios) 



Btejutiolus brevipinnis 

 (Guntlicr) 



Stromateidao (hutterfishes) 

 PsencK pacific)i.<t Meek 

 and IIiUiebrand_ 



Mugilidae (mullets) 

 Agoiiostoriius monticola 

 (Bancroft) 



MugilcuTema Valenciennes 



Polyneniidae (tlircadfins) 

 Pnh/dacfi/lii.t appToiJmans 



(Lay and Bennett) 



Poli/dactijlns opercularis 



(Gill) 



Monacantliidae (filefishes) 

 Alntera mnuoceros 



(Linnaeus) 



Ahitera scnpta (Osbeck).. 



Balistidae (triggerflshes) 

 lialistes pnlyUpis 



Steindachner 



Canthidenitis i7iacida(us 



(Bloch) 



Life stage 



Adult Juvenile 



Total 

 captured 



Numher 

 3 



6,21.1 



105 



44 



29S 



218 



43 



1,348 



5 

 315 



339 



Range of 



standard 



length 



Afm. 

 72-24() 



9-212 



I(J-85 

 17-101 

 17-100 



11-263 



29-143 



15-108 



103-154 

 10-163 



35-68 

 34-42 



63-137 

 32-103 

 18-59 



Season 



Spring Fall 



* Specimens cataloged in Marine Vertebrates collection, Scrippe Inatitn- 

 tion of < U-eanocraphy. 



' Adults observed but not captured. 



* .Specilic name unknown. 



* Adulta collected by method other than small purse seine. 

 ' Fork Icnt^th. 



scombrids can lie ascribed to variation in collection 

 methods rather than to seasonal differences. Adult 

 frigate mackerel, Anxis thazard, black skipjack, 

 Euthynnus Uneatus, oceanic skipjack, and yellowfin 

 tuna were present during both seasons, and all are 

 known to associate with flotsam. 



The mountain mullet, Agonostonnis monlicola, was 

 not in the spring collections but occurred in 10 of the 

 47 fall collections. This species inhabits marine 

 waters only as a pi-ejuvenile (Ebeling, lOtil). Thus 

 its occurrence in only the fall collections could be 

 clue to a seasonal difference in reproductive activities. 



The remaintler of the species that were taken dur- 

 ing only 1 sea.son were relatively uncommon in the 

 collections. Their absence during 1 season could be 

 due to chance alone. 



LIFE STAGE OF FISHES 

 ASSOCIATED WITH FLOTSAM 



Nearly- all of the fishes observetl and captured be- 

 neath drifting objects were juveniles; however, adult 

 sharks, Carcharhinus limhatus (Miiller and Henle) 

 and Carcharhinus azureus (Gilbert and Starks), and 

 schools of adult Caranx caballus, Selar crumenoph- 

 thalmits, Coryphaena hippvrt(s, Secfator ocytirus, and 

 Euthynnus Uneatus were observed. With the ex- 

 ception of S. ocyurus, these adults did not swim as 

 close to the object as did the smaller fishes, and they 

 remained near it only for short periods. None of 

 these adults were captured by the small purse seine. 

 Some were captured, however, by other methods. 

 Owing to the infrequent capture of the.se adults and 

 to the difficulty of ascertaining whether or not they 

 were in fact associated with a particular otiject, 

 our presentation is limited to the fishes captured by 

 the small seine. Canthidermis maciilatus was the 

 only species that frequently occurred both as adult 

 and juveiiil(>; both stages were captured in the seine. 



To determine if the size of the fishes was related 

 to the distance of an object from shore, the shortest 

 distance to the shore from the location of each col- 

 lection was measured to the nearest nautical mile. 

 The length measurements of species from different 

 collections captured at the same distance from shore 

 were combined, and a mean and range were estab- 

 lished (figs. 2, 3, and 4). 



The mean and minimum length of Al)udcf(hif 

 saxatilis and Seriola sp. increased with the distance 

 of an object from shore (chi-scjuare test for two inde- 

 pendent samples, p<.01) — figs. 2 and 3. The 



16 



U.S. FISH AND WILDLIFE SERVICE 



