with rotenone over a 2-yr period at intervals of 1 mo, 

 3 mo, and 6 mo. She found rapid recolonization but 

 with lower densities of recolonizers in winter than 

 in summer. During 26 monthly samples, only one of 

 the original species did not recolonize the pool, while 

 13 additional species were found. In Pool 2, which 

 was sampled in 3-mo intervals, 14 species were taken 

 in the initial sample, 7-12 in subsequent samples. 

 Three of the original 14 species failed to recolonize, 

 but 8 additional species were taken. During four 

 repeat visits to Pool 3, the number of species varied 

 between 9 and 14, all but 1 species recolonized the 

 pool, and 5 additional species were recorded. 



My study and those of Thomson and Lehner 

 (1976), Grossman (1982), and Beckley (1985) indicate 

 great resilience of species of tidepool fishes in 

 tropical and temperate waters. Recolonization is 

 quite rapid, within a matter of weeks. 



Acknowledgments 



I thank the students and teaching assistants in my 

 ichthyology course for helping to collect the material. 

 James Dooley made the second 1982 collection. N. 

 W. Riser of the Marine Science and Maritime Studies 

 Center identified the invertebrates. Comments on 

 drafts of this note were provided by G. D. Grossman, 

 J. Randall, N. W. Riser, V. G. Springer, and A. B. 

 Williams. 



Literature Cited 



Beckley, L. E. 



1985. Tidepool fishes: Recolonization after experimental elim- 

 ination. J. Exper. Mar. Biol. Ecol. 85:287-295. 

 Gibson, R. N. 



1982. Recent studies on the biology of intertidal fishes. 

 Oceanogr. Mar. Biol. Ann. Rev. 20:363-414. 

 Grossman, G. D. 



1982. Dynamics and organization of a rocky intertidal fish 

 assemblage: the persistence and resilience of taxocene struc- 

 ture Am. Nat. 119:611-637. 

 Thomson, D. A., and C. E. Lehner. 



1976. Resilience of a rocky intertidal fish community in a 

 physically unstable environment. J. Exper. Mar. Biol. Ecol. 

 22:1-29. 



Bruce B. Collette 



Marine Science and 

 Maritime Studies Center, 

 Northeastern University, 

 Nahant, MA 01908 



and 



Systematics Laboratory, 

 National Marine Fisheries Service, 

 National Museum of Natural History, 

 Washington, DC 20560 



PARASITES OF BENTHIC AMPHIPODS: 

 CILIATES 



Benthic gammaridean amphipods were sampled dur- 

 ing a 2V2-yr period as a part of the Northeast Moni- 

 toring Program (NEMP) of the Northeast Fisheries 

 Center, National Marine Fisheries Service The am- 

 phipod survey was designed to determine the kinds 

 of parasites and pathological conditions occurring 

 in amphipod populations that live in and on the 

 sediments of the continental shelf from Maine to 

 North Carolina. Microsporidans of the sampled am- 

 phipods have been discussed by Johnson (1985), and 

 this paper presents and discusses data on host 

 distribution, prevalence, effects on the host, and 

 probable relationships, of ciliates parasitizing am- 

 phipods from the same samples. 



Materials and Methods 



Benthic amphipods were collected from 35 sta- 

 tions, mainly on the Georges Bank and Mid-Atlantic 

 Bight (Fig. 1). Amphipods were sampled during 11 

 cruises, July 1980-November 1982 (Table 1). Each 

 station was sampled from 1 to 10 times during the 

 survey. The 11 stations indicated by solid circles on 

 Figure 1 had the most consistent and numerous 

 populations of amphipods, were sampled at least five 

 times each, and yielded the majority of data 

 presented here A Smith-Mclntyre grab and occa- 

 sionally an epibenthic sled or scallop dredge were 

 used to obtain the samples. Up to 30 individuals of 

 each species present in a sample, and sometimes 

 more depending on numbers present, were prepared 

 for histological study. Details of collecting pro- 

 cedures and preparation of the amphipods for study 

 are given by Johnson (1985). 



Results 



Host and geographic distribution of ciliate infec- 

 tion is given in Table 1. Ciliate-infected amphipods 

 were taken in samples from at least one station on 

 every cruise There was no indication that prevalence 

 was influenced by the season of the year or location 

 of the positive stations. The majority of infected 

 specimens were Ampelisca agassizi (Judd), but 

 prevalence of ciliate infection was lower in A. agassizi 

 than in the other species found infected (Pontogeneia 

 inermis Kr0yer, Phoxocephalus holbolli Kr0yer, Har- 

 pinia propinqua Sars, and unidentified haustoriids) 

 (Table 2). In three instances, at station 33, cruise G; 

 station 48, cruise I; and station 57, cruise E, in- 

 dividuals ofH. propinqua or P. holbolli were infected 



204 



FISHERY BULLETIN: VOL. 84, NO. 1 



