Synopsis
The biomass of available forage is a key factor in controlling the abundance and distribution of surface tropical tunas, as they have high energy demands and live in a poor environment. The direct estimate of this forage biomass is not possible with existing techniques. Thus we have investigated the lower link, i.e. the plankton organisms which are the food of fishes preyed upon by tunas. In a previous study, this fraction of the zooplankton has been identified, both by taxa and by size, by analysing the stomach contents of the fishes which are the preys of tunas. In this paper, we use 331 plankton samples from tuna fishing grounds of the tropical Indian ocean, to define the characteristics of the planktonic fraction actually participating in the tuna food chain. Main results are as follows: (1) Only 15–27 % of the total zooplanktonic biomass (> 1 mm) is actually accessible for the fishes preyed upon by surface tunas. This ‘useful’ part of the zooplankton is a well defined fraction of the planktonic population which remains in the 0–170 meters water layer during daylight hours. This part of the zooplankton accounts for a variable percentage of its total biomass the different geographic areas and represents the most relevant parameter to assess the potential richness of a given area for surface tunas. (2) From areas where fishing for surface tunas is poor to those where fishing is successful, it is observed that the total zooplankton biomass increases by a factor of 4 whereas the biomass of the ‘useful’ fraction increases by a factor of 7. This disproportionate increase is due to the facts that the potential preys of fishes preyed upon by tunas represent a growing fraction of the zooplankton and that a growing proportion of this fraction remains by day in the 0–170 meter water layer, therefore becoming available for the day-feeders which comprise most of the prey-fishes of surface tunas.
Similar content being viewed by others
References cited
Alverson, F.G. 1961. Daylight surface occurrence of myctophid fishes off the coast of South America. Pacif Sci. 15: 483.
Bard, F.X. & O. Pezennec. 1991. Analyse des contenus stomacaux des albacores (T. albacares) pchés à la senne dans le golfe de Guinée. ICCAT Collective volume of scientific papers 35, SCRS 90/67: 1–7.
Borodulina, O.D. 1982. Food composition of yellowfin tunaThunnus albacares. J. Ichthyol. 21: 38–46.
Cayré, P. 1991. Behaviour of yellowfin tuna (Thunnus albacares) and skipjack tuna (Katsuwonus pelamis) around fish aggregating devices (FADS) in the Comoros Islands as determined by ultrasonic tracking. Aquat. Living Resour. 4: 1–12.
Clarke, T.A. 1983. Comparison of abundance estimates of small fishes by three towed nets and preliminary results of the use of small purse-seines as sampling devices. Biol. Oceanogr. 2: 311–340.
Dizon, A.E., R.W. Brill & H.S.H. Yuen. 1978. Correlations between environment, physiology and activity, and the effects of thermoregulation in skipjack tuna. pp. 233–260.In: G.D. Sharp & A.E. Dizon(ed.) The Physiological Ecology of Tunas, Academic Press, New York.
Dragovich, A. & T. Potthoff. 1972. Comparative study of food of skipjack and yellowfin tunas off the coast of West Africa. U.S. Fish. Bull. 70: 1087–1110.
Giguère, L.A., J.F. St Pierre, B. Bernier, A. Vezina & J.G. Rondeau. 1989. Can we estimate the true weight of zooplankton after chemical preservation? Can. J. Fish. Aquat. Sci. 46: 522–527.
Grandperrin, R. 1975. Structures trophiques aboutissant aux thons de Longue Ligne dans le Pacifique Sud-Ouest tropical. Thèse de Doctorat d'Etat, Université de Provence, Marseille. 296 pp.
Herbland, A. 1990. L'oligotrophie: un concept en évolution. ICCAT Collective volume of scientific papers 32, SCRS 89/61: 169–174.
Holland, K.N., R.W. Brill & R.K.C. Chang. 1990. Horizontal and vertical movements of yellowfin and bigeye tunas associated with fish aggregating devices. U.S. Fish. Bull. 88: 493–507.
Hunter, J.R., A.W. Argue, W.H. Bayliff, A.E. Dizon, A. Fonteneau, D. Goodman & G.R. Seckel. 1986. The dynamics of tuna movements: an evaluation of past and future research. FAO Fish. Tech. Paper 277: 1–78.
Kitchell, J.F., W.H. Neill, A.E. Dizon & J.J. Magnuson. 1978. Bio-energetic spectra of skipjack and yellowfin tunas. pp. 357–368.In: G.D. Sharp & A.E. Dizon(ed.) The Physiological Ecology of Tunas, Academic Press, New York.
Kobayashi, H. & Y. Yamaguchi. 1971. Feeding ecology and hoocking tendency of tunas and marlins in the eastern equatorial Pacific. Bull. Jap. Soc. Sci. Fish. 37: 83–89.
Kornilova, G.N. 1981. Feeding of yellowfin tuna,Thunnus albacares and bigeye tuna,Thunnus obesus, in the equatorial zone of the Indian Ocean. J. Ichthyol. 20: 111–119.
Legand, M., P. Bourret, P. Fourmanoir, R. Grandperrin, J.A. Gueredrat, A. Michel, P. Rancurel, R. Repelin & C. Roger. 1972. Relations trophiques et distributions verticales en milieu pélagique dans I'océan Pacifique intertropical. Cahiers ORSTOM, Sér. oceanogr. 10: 303–393.
Lemasson, L. 1990. Relations production halieutique-environnement. ICCAT Collective volume of scientific papers 32. SCRS 89/57: 133–136.
Longhurst, A.R. & D. Pauly. 1987. Ecology of tropical oceans. Academic Press, New York. 407 pp.
Medina-Gaertner, M. 1988. Relation entre l'alimentation des poissons et le zooplankton de la baie de Dakar. Inv. Pesq. 52: 155–192.
Nakamura, E.L. 1965. Food and feeding habits of skipjack tuna (Katsuwonus pelamis) from the Marquesas and Tuamotu Islands. Trans. Amer. Fish. Soc. 94: 236–242.
Olson, R.J. & C.H. Boggs. 1986. Apex predation by yellowfin tuna (Thunnus albacares): independent estimates from gastric evacuation and stomach contents, bioenergetics and cesium concentrations. Can. J. Fish. Aquat. Sci. 43: 1760–1775.
Parin. N.V., 1968. Ichthyofauna of the epipelagic zone. Translated by Israel programme for scientific translations 1970, IPST Cat. no. 5528. 206 pp.
Pelczarski, W. 1988. Examination of food of yellowfin tuna (Thunnus albacares) and bigeye tuna (Thunnus obesus) from the open waters of the Central Atlantic. ICCAT Collective volume of scientific papers 28, SCRS 87/55: 58–73.
Petit, M. & J.M. Stretta. 1992. Théorie cohérente du comportement des thonidés dans leur habitat. ICCAT Collective volume of scientific papers 39, SCRS 91/58: 332–336.
Pitman, R.L. & L.T. Ballance. 1990. Daytime feeding by Leach's storm-petrel on a midwater fish in the eastern tropical Pacific. The Condor 92: 524–527.
Roger, C. & R. Grandperrin. 1976. Pelagic food webs in the tropical Pacific. Limnol. oceanogr. 21: 731–735.
Stequert, B. & F. Marsac. 1976. La pêche de surface des thonidés tropicaux dans l'Océan Indien. FAO Doc. Tech. Pêches 282. 213 pp.
Stretta, J.M. & M. Petit. 1992. Déterminisme du déplacement des thonidés et variabilitié de l'environnement. ICCAT Collective volume of scientific papers 39. SCRS 91/57: 322–331.
Sund, P.N., M. Blackburn & F. Williams. 1981. Tunas and their environment in the Pacific Ocean: a review. Oceanogr. Mar. Biol. 19: 443–512.
Valle, S., N. Mezentseva & E. Rodriguez. 1979. Contenido estomacal del atun de aleta amarilla (Thunnus albacares) en el Atlantico Centro Oriental. Oceanogr. Trop. 18: 163–185.
Yang, W.S. & Y. Gong. 1987. The vertical distribution of tunas and billfishes, and fishing efficiency between Korean regular and deep longlines in the Atlantic Ocean. ICCAT Collective volume of scientific papers 26, SCRS 86/81: 184–187.
Yuen, H.S.H. 1970. Behavior of skipjack tunaKatsuwonus pelamis as determined by tracking with ultrasonic devices. J. Fish. Res. Board Can. 27: 2071–2079.
Zavala-Camin, L.A. 1986. Sobre el ciclo alimentario en los estudios de contenido estomacal de atunes y afines. ICCAT, Collective volume of scientific papers 26, SCRS 86/34: 582–583.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Roger, C. The plankton of the tropical western Indian ocean as a biomass indirectly supporting surface tunas (yellowfin,Thunnus albacares and skipjack,Katsuwonus pelamis). Environ Biol Fish 39, 161–172 (1994). https://doi.org/10.1007/BF00004934
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00004934