Distribution patterns, abundance and population dynamics of the euphausiidsNyctiphanes capensis andEuphausia hanseni in the northern Benguela upwelling system

Abstract

Distribution patterns, population structure and biomass of the euphausiidsNyctiphanes capensis andEuphausia hanseni were examined off the coast of Namibia, southwest Africa, in relation to temperature, depth and season, from data collected on nine surveys from September 1982 to March 1984. High densities ofN. capensis were found in the shallow coastal waters (<200 m), with the biomass of adults ranging from 675 to 5 706 mg dry wt m−2. For adultE. hanseni, the biomass was an order of magnitude lower, ranging from 65 to 505 mg dry wt m−2, with most specimens occurring over the shelf break at depths of 200 to 1000 m. These distribution patterns remained relatively constant throughout the year, despite seasonal differences in upwelling events. Both species displayed continuous breeding, with 43 to 82% of the adult femaleE. hanseni being fertilized, while a much lower proportion ofN. capensis females were reproductively active (0.5 to 26%). Different breeding strategies were adopted by these two euphausiid species, withE. hanseni producing frequent broods (14.8 broods in 6 mo) consisting of relatively large eggs which are released into the sea, andN. capensis exhibiting a lower frequency of spawning, with broods consisting of large numbers of relatively small eggs, protected by a brood pouch. These strategies enable both species to maintain high densities throughout the year in a fluctuating physical environment. Growth rate estimated from size-frequency distributions were 0.003 to 0.063 mm d−1 forN. capensis and 0.077 to 0.083 mm d−1 forE. hanseni, suggesting an adult lifespan of approximately 6 mo for both species. Maximum sizes were attained in September, withN. capensis reaching a total length of 21 mm (in contrast to all previous studies onN. capensis, where the maximum size recorded was only 13 mm total length) andE. hanseni a total length of 33 mm.

This is a preview of subscription content, access via your institution.

Literature cited

  1. Agenbag, J. J., Shannon, L. V. (1988). A suggested physical explanation for the existence of a biological boundary at 24°30′S in the Benguela system. S. Afr. J. mar. Sci. 6: 119–132

    Google Scholar 

  2. Barange, M. (1990). Vertical migration and habitat partitioning of six euphausiid species in the northern Benguela upwelling system. J. Plankton Res 12: 1223–1237

    Google Scholar 

  3. Boden, B. P. (1954). The euphausiid crustaceans of Southern African waters. Trans. R. Soc. S. Afr. 34: 181–243

    Google Scholar 

  4. Boden, B. P. (1956). Euphausiacea of the Benguela Current. First Survey, R. R. S. “William Scoresby”, March 1950. ‘Discovery’ Rep. 27: 339–376

    Google Scholar 

  5. Boucher, J. (1982). Peuplement de copépodes des upwellings côtiers nord-ouest africains. II. Maintien de la localisation spatiale. Oceanol. Acta 5: 199–207

    Google Scholar 

  6. Boyd, A. J., Agenbag, J. J. (1985). Seasonal trends in the longshore distribution of surface temperatures off southwestern Africa, 18–34°S, and their relation to subsurface conditions and currents in the area 21–24°S. In: Bas, C., Margalef, R., Rubies, P. (eds.) International symposium on the most important upwelling areas off western Africa (Cape Blanco and Benguela). Vol. I. Instituto de Investigaciones Pesqueras, Barcelona, p. 119–148

    Google Scholar 

  7. Boyd, A. J., Salat, J., Masó, M. (1987). The seasonal intrusion of relatively saline water on the shelf off northern and central Namibia. S. Afr. J. mar. Sci. 5: 107–120

    Google Scholar 

  8. Brinton, E. (1976). Population biology ofEuphausia pacifica off Southern California. Fish. Bull. U.S. 74: 733–762

    Google Scholar 

  9. Childress, J. J., Price, M. H. (1978). Growth rate of the bathypelagic crustaceanGnathophausia ingens (Mysidacea: Lophogastridae). I. Dimensional growth and population structure. Mar. Biol. 50: 47–62

    Google Scholar 

  10. Gibbons, M. J., Barange, M., Pillar, S. C. (1991a) Vertical migration and feeding ofEuphausia lucens (Euphausiacea) in the Southern Benguela. J. Plankton Res. (in press)

  11. Gibbons, M. J., Pillar, S.C., Stuart, V. (1991b). Selective carnivory byEuphausia lucens. Contin. Shelf Res. (in press)

  12. Giguere, L. A., St-Pierre, J.-F., Bernier, B., Vèzina, A., Rondeau, J.-G. (1989). Can we estimate the true weight of zooplankton samples after chemical preservation? Can. J. Fish. aquat. Sciences 46: 522–527

    Google Scholar 

  13. Hosie, G. W., Ritz, D. A. (1983). Contribution of moulting and eggs to secondary production inNyctiphanes australis (Crustacea: Euphausiacea). Mar. Biol. 77: 215–220

    Google Scholar 

  14. Kimmerer, W. J., McKinnon, A. D. (1987). Zooplankton in a marine bay. II. Vertical migration to maintain horizontal distributions. Mar. Ecol. Prog. Ser. 41: 53–60

    Google Scholar 

  15. Konchina, Yu. V. (1986). Distribution and feeding of South African horse mackerel and hake in the Namibian shelf waters. Colln scient. Pap. int. Common SE. Atl. Fish. 13: 7–18

    Google Scholar 

  16. Kruger, I., Boyd, A. J. (1984). Investigations into the hydrology and plankton of the surface waters off Southwestern Africa in IC-SEAF divisions 1.3, 1.4 and 1.5 in 1982/83. Colln scient. Pap. int. Commn SE. Atl. Fish. 11: 109–133

    Google Scholar 

  17. Le Clus, F., Kruger, I. (1982). Time and space distribution of temperature, salinity, plankton and fish eggs of South West Africa in 1980/81. A preliminary data report. Colln scient. Pap. int. Commn SE. Atl. Fish. 9: 121–145

    Google Scholar 

  18. Lindley, J. A. (1982). Continuous plankton records: geographical variations in numerical abundance, biomass and production of euphausiids in the North Atlantic Ocean and the North Sea. Mar. Biol. 71: 7–10

    Google Scholar 

  19. Macpherson, E. (1983). Ecología trófica de peces en las costas de Namibia. I. Hábitos alimentarios. Resultados Exped. cient. (Supl. Investigación pesq.) 11: 81–137

    Google Scholar 

  20. Macpherson, E., Roel, B. A. (1987). Trophic relationships in the demersal fish community off Namibia. S. Afr. J. mar. Sci. 5: 585–596.

    Google Scholar 

  21. Mauchline, J., Fisher, L. R. (1969). The biology of the euphausiids. Adv. mar. Biol. 7: 1–454

    Google Scholar 

  22. Meira, C. (1970). Contribuição para o estudo dos eufausiáceos do arquipélago de Cabo Verde. Centro Biol. aquát. trop. 19: 1–25

    Google Scholar 

  23. Nepgen, C. S. de V. (1957). The euphausiids of the west coast of Africa. Investl Rep. Div. Fish. S. Afr. 28: 1–30

    Google Scholar 

  24. Olivar, M. P., Barange, M. (1990). Zooplankton of the northern Benguela region in a quiescent upwelling period. J. Plankton Res. 12: 1023–1044

    Google Scholar 

  25. Peterson, W. T., Miller, C. B., Hutchinson, A. (1979). Zonation and maintenance of copepod populations in the Oregon upwelling zone. Deep-Sea Res. 26A: 467–494

    Google Scholar 

  26. Pillar, S. C. (1984). Laboratory studies on the larval growth and development ofEuphausia lucens (Euphausiacea). S. Afr. J. mar. Sci. 2: 43–48

    Google Scholar 

  27. Pillar, S. C. (1985). Laboratory studies on the larval growth and development ofNyctiphanes capensis (Euphausiacea). J. Plankton Res. 7: 223–240

    Google Scholar 

  28. Pillar, S. C. (1986). Temporal and spatial variations in copepod and euphausiid biomass off the Southern and South-western coasts of South Africa in 1977/78. S. Afr. J. mar. Sci. 4: 219–229

    Google Scholar 

  29. Pillar, S. C., Armstrong, D. A., Hutchings, L. (1989). Vertical migration, dispersal and transport ofEuphausia lucens in the Southern Benguela Current. Mar. Ecol. Prog. Ser. 53: 179–190

    Google Scholar 

  30. Pillar, S. C., Stuart, V. (1988). Population structure, reproductive biology and maintenance ofEuphausia lucens in the southern Benguela current. J. Plankton Res. 10: 1083–1098

    Google Scholar 

  31. Ponomareva, L. A. (1963). Euphausiids of the North Pacific, their distribution and ecology. Trud\(\bar y\) Inst. Okeanol. [Translated by Israel program for Scientific Translations, Jerusalem 1966, IPST Catalog No. 1368]

  32. Roel, B. A., Macpherson, E. (1988). Feeding ofMerluccius capensis andMerluccius paradoxus. S. Afr. J. mar. Sci. 6: 227–244

    Google Scholar 

  33. Ritz, D. A., Hosie, G. W. (1982). Production of the euphausiidNyctiphanes australis in Storm Bay, South-Eastern Tasmania. Mar. Biol. 68: 103–108

    Google Scholar 

  34. Ross, R. M., Daly, K. L., English, T. S. (1982). Reproductive cycle and fecundity ofEuphausia pacifica in Puget Sound, Washington. Limnol. Oceanogr. 27: 304–314

    Google Scholar 

  35. Shannon, L. V. (1985). The Benguela ecosystem. Part I. Evolution of the Benguela, physical features and processes. Oceanogr. mar. Biol. A. Rev. 23: 105–182

    Google Scholar 

  36. Shannon, L. V., Boyd, A. J., Brundit, G. B., Tauton-Clark, J. (1986). On the existence of an El Niño-type phenomenon in the Benguela System. J. mar. Res. 44: 495–520

    Google Scholar 

  37. Siegel, V. (1987). Age and growth of Antarctic Euphausiacea (Crustacea) under natural conditions. Mar. Biol. 96: 483–495

    Google Scholar 

  38. Simard, Y., Ladurataye, R., Therriault, J.-C. (1986). Aggregation of euphausiids along a coastal shelf in an upwelling environment. Mar. Ecol. Prog. Ser. 32: 203–215

    Google Scholar 

  39. Smiles, M. C., Pearcy, W. G. (1971). Size structure and growth rate ofEuphausia pacifica off the Oregon coast. Fish. Bull. U.S. 69: 79–86

    Google Scholar 

  40. Stuart, V. (1986). Feeding and metabolism ofEuphausia lucens (Euphausiacea) in the southern Benguela current. Mar. Ecol. Prog. Ser. 30: 117–125

    Google Scholar 

  41. Stuart, V. (1989). Observations on the feeding ofEuphausia lucens on natural phytoplankton suspensions in the Southern Benguela upwelling region. Contin. Shelf Res. 9: 1017–1028

    Google Scholar 

  42. Stuart, V., Nicol, S. (1986). The reproductive potential of three euphausiid species from the southern Benguela region. J. exp. mar. Biol. Ecol. 103: 267–274

    Google Scholar 

  43. Stuart, V., Pillar, S. C. (1988). Growth and production ofEuphausia lucens in the southern Benguela current. J. Plankton Res. 10: 1099–1112

    Google Scholar 

  44. Stuart, V., Pillar, S. C. (1990). Diel grazing patterns of all ontogenic stages ofEuphausia lucens and in situ predation rates on copepods in the Southern Benguela upwelling region. Mar. Ecol. Prog. Ser. 64: 227–241

    Google Scholar 

  45. Williams, R., Fragopoulu, N. (1985). Vertical distribution and nocturnal migration ofNyctiphanes couchii (Crustacea: Euphausiacea) in relation to the summer thermocline in the Celtic Sea. Mar. Biol. 89: 257–262

    Google Scholar 

Download references

Author information

Affiliations

Authors

Additional information

Communicated by J.M. Pérès, Marseille

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Barange, M., Stuart, V. Distribution patterns, abundance and population dynamics of the euphausiidsNyctiphanes capensis andEuphausia hanseni in the northern Benguela upwelling system. Mar. Biol. 109, 93–101 (1991). https://doi.org/10.1007/BF01320235

Download citation

Keywords

  • Biomass
  • Distribution Pattern
  • Maximum Size
  • Seasonal Difference
  • Breeding Strategy