Abstract
Net-captured aggregate stages of the salp Thalia democratica were fed naturally occurring particles in 2-liter bottles onboard ship. The goal was to compare clearance rates of net-captured T. democratica fed natural particles to clearance rates previously determined in laboratoryborn T. democratica fed monocultures of phytoplankton. On a cruise from 19–29 April, 1979, clearance rates were estimated by monitoring the decrease in concentration of particles with a multi-channel Coulter Counter TA II over a particle size range of 2 to 32 μm equivalent spherical diameter (E.S.D.). Clearance rates were slightly lower than those measured in the laboratory, decreasing 3-fold over an 18-fold increase in the initial food concentration. Ingestion rates were slightly higher than those measured in the laboratory, increasing about 6-fold over the same range of food concentration. Within the particle concentration range examined (0.08 to 1.34 mm3l-1), there was no lower threshold of food concentration below which clearance of particles ceased. There was no effect of the concentration of T. democratica on clearance rate over a range of 2.5 to 11.5 salps l-1. The mean hourly ration was 2.0% of body carbon.
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Literature cited
Alldredge, A. L.: The impact of appendicularian grazing on natural food concentrations in situ. Limnol. Oceanogr. 26, 247–257 (1981)
Alldredge, A. L. and L. P. Madin: Pelagic tunicates: unique herbivores in the marine plankton. Bio Science 32(8), 655–663 (1982)
Carlisle, D. B.: Alcune osservazioni sulla meccanica dell' alimentaxione della Salpa. Publ. Staz. zool. Napoli 22, 146–154 (1950)
Conover, R. J.: Feeding interactions in the pelagic zone. Rapp. P.-v. Reun. Cons. int. Explor. Mer 173, 66–76 (1978)
Deibel, D.: Blooms of the pelagic tunicate, Dolioletta gegenbauri: are they associated with Gulf Stream frontal eddies? J. mar. Res. 43 (1985)
Deibel, D.: Laboratory determined mortality, fecundity and growth rates of Thalia democratica Forskal and Dolioletta gegenbauri Uljanin (Tunicata, Thaliacea). J. Plankton Res. 4, 143–153 (1982 a)
Deibel, D.: Laboratory-measured grazing and ingestion rates of the salp, Thalia democratica Forskal, and the doliolid, Dolioletta gegenbauri Uljanin (Tunicata, Thaliacea). J. Plankton Res 4, 189–201 (1982 b)
Fedele, M.: Sul complesso delle funzioni che intervengono nel meccanismo ingestivo dei Salpidae. Atti. Accad. naz. Lincei Rc. 17, 241–245 (1933 a)
Fedele, M.: Sulla nutrizione degli animali pelagici III. Ricerche sui Salpidae. Boll. Soc. Nat. Napoli 45, 49–117 (1933 b)
Frost, B. W.: Effects of size and concentration of food particles on the feeding behavior of the marine planktonic copepod Calanus pacificus. Limnol. Oceanogr. 17, 805–815 (1972)
Harbison, G. R. and V. L. McAlister: The filter-feeding rates and particle retention efficiencies of three species of Cyclosalpa (Tunicata, Thaliacea). Limnol. Oceanogr. 24, 875–892 (1979)
Harbison, G. R. and V. L. McAlister: Fact and artifact in copepod feeding experiments. Limnol. Oceanogr. 25, 971–981 (1980)
Harbison, G. R. and R. W. Gilmer: The feeding rates of the pelagic tunicate Pegea confoederata and two other salps. Limnol. Oceanogr. 21, 917–928 (1976)
Heron, A. C.: Population ecology of a colonizing species: the pelagic tunicate Thalia democratica I. Individual growth rates and generation time. Oecologia (Berl.). 10, 269–293 (1972)
Madin, L. P.: Field observations on the feeding behavior of salps (Tunicata: Thaliacea). Mar. Biol. 25, 143–147 (1974)
Madin, L. P. and C. M. Cetta: The use of gut fluorescence to estimate grazing by oceanic salps. J. Plankton Res. 6, 475–492 (1984)
Mullin, M. M.: Some factors affecting the feeding of marine copepods of the genus Calanus. Limnol. Oceanogr. 8, 239–250 (1963)
Mullin, M. M.: In situ measurement of filtering rates of the salp, Thalia democratica, on phytoplankton and bacteria. J. Plankton Res. 5, 279–289 (1983)
Paffenhöfer, G.-A.: Feeding, growth, and food conversion of the marine planktonic copepod Calanus helgolandicus. Limnol. Oceanogr. 21, 39–50 (1976)
Paffenhöfer, G.-A., D. Deibel L. P. Atkinson and W. M. Dunstan: The relation of concentration and size distribution of suspended particulate matter to hydrography in Onslow Bay, North Carolina. Deep-Sea Res 27, (A) 435–447 (1980)
Thompson, H.: Pelagic tunicates of Australia, 196 pp. Melbourne: Comm. Council Sci. indust. Res. 1948
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Communicated by R. W. Doyle, Halifax
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Deibel, D. Clearance rates of the salp Thalia democratica fed naturally occurring particles. Marine Biology 86, 47–54 (1985). https://doi.org/10.1007/BF00392578
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DOI: https://doi.org/10.1007/BF00392578