Journal of comparative physiology

, Volume 122, Issue 2, pp 251–271 | Cite as

Emergence and development of the electric organ discharge in the mormyrid fish,Pollimyrus isidori

I. The larval discharge
  • G. W. Max Westby
  • Frank Kirschbaum


The paper describes the first part of a longitudinal study of the development of electric organ discharge (EOD) in the mormyrid fishPollimyrus isidori. Laboratory bred larvae were continuously monitored for EOD onset in a small glass recording cell fitted with recording electrodes (Fig. 1). Temperature was held at 27 °C+-0.05°.
  1. 1.

    First recognisable EODs were recorded on Day 8 following spawning (Fig. 4). The EOD was about 10 ms in duration in contrast to 50 μs in the adult (Fig. 2). The head positive main phase of the larval EOD soon appears (Fig. 10) and is thus of the opposite polarity to the adult discharge.

  2. 2.

    During the first 6 h following the first EOD the amplitude and discharge patterns changed very rapidly. The EOD of a reference fish was analysed discharge by discharge over this period (Fig. 5). Amplitude increased by over 400% from an initial 50 μV (p-p) recorded potential. Most discharges occurred in trains of up to 14 EODs with relatively constant intra-train intervals of 100–150 ms (Figs. 7, 8, 13).Inter-train intervals decreased very rapidly from minutes to tens of seconds over the first 6 h (Fig. 9). Longer trains tended to occur more often during swimming activity (Fig. 6).

  3. 3.

    The first clear changes in form of discharge occurred between 8 and 10 h post-EOD onset (Fig. 10). Secondary and tertiary discharges at 6 ms and 12 ms intervals from the main EOD commenced during the 12th and 18th h respectively. By 24 h all fish in the peer group (Fig. 11) were producing multiple EODs. At 36 h all these discharges had stopped but were soon replaced by large, secondary EODs (Fig. 14). These were in turn replaced by 8 ms multiples (Fig. 15) for a transitory period and by 70 h all multiple EODs had ceased.

  4. 4.

    Morphological studies show that a primitive larval electric organ is the only generating structure present during the period of larval discharge.

  5. 5.

    Physiological models are proposed to account for the observed discharge pattern variations during the initial developmental period. 12 ms multiple EODs appear to be ‘self-echoing’ -an oscillation of the electrosensory system due to the incomplete establishment of the afferent control system which normally inhibits such feedback.



Discharge Pattern Recording Electrode Transitory Period Swimming Activity Physiological Model 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bauer, R.: High electric discharge frequency during aggressive behaviour in a mormyrid fishGnathonemus petersii. Experientia28, 669 (1972)Google Scholar
  2. Bell, C.C., Myers, J.P., Russell, C.J.: Electric organ discharge patterns during dominance related behavioural displays inGnathonemus petersii (Mormyridae). J. comp. Physiol.92, 201–228 (1974)Google Scholar
  3. Bennett, M.V.L., Steinbach, A.B.: Influence of electric organ control system on electrosensory afferent pathways in mormyrids. In: Neurobiology of cerebellar evolution and development (ed. E.R. Llinas), pp. 207–214. Chicago: Amer. Med. Assoc. (1969)Google Scholar
  4. Birkholz, J.: Zufällige Nachzucht beiPetrocephalus bovei. Das Aquarium3, 201–203 (1969)Google Scholar
  5. Birkholz, J.: Nachwuchs beiPetrocephalus bovei. Das Aquarium4, 340–342 (1970)Google Scholar
  6. Daget, J.: Alevins deMormyrus rume. Bull. Soc. Zool. France83, 200–204 (1958)Google Scholar
  7. Dahlgren, U.: Origin of the electric tissue ofGymnarchus niloticus. Dept. Marine Biol., Carnegie Institute, Washington. Papers from the Tortugas Laboratory6 (183) 161–194 (1914)Google Scholar
  8. Denizot, J.P., Kirschbaum, F., Westby, G.W.M., Tsuji, S.: On the larval electric organ of the mormyrid fishPollimyrus isidori. J. Neurocytol., in press (1977)Google Scholar
  9. Heymer, A., Harder, W.: Erstes Auftreten der elektrischen Entladungen bei einem jungen Mormyriden. Naturwissenschaften62, 489 (1975)Google Scholar
  10. Hopkins, C.D.: Electric communication in fish. Amer. Scientist62, 426–437 (1974a)Google Scholar
  11. Hopkins, C.D.: Electric communication: functions in the social behaviour ofEigenmannia virescens. Behaviour50, 270–305 (1974b)Google Scholar
  12. Johnels, A.G.: Notes on fishes from the Gambia river. Ark. Zool.6, 327–411 (1954)Google Scholar
  13. Kirschbaum, F.: Environmental factors control the periodical reproduction of tropical electric fish. Experientia31, 1159–1160 (1975)Google Scholar
  14. Kirschbaum, F.: Electric organ ontogeny: Distinct larval organ precedes the adult organ in weakly electric fish. Naturwissenschaften64, 387–388 (1977a)Google Scholar
  15. Kirschbaum, F.: Ontogeny of larval and adult electric organ in the mormyrid fishPollimyrus isidori. I. Light microscopic studies. In preparation (1977b)Google Scholar
  16. Kirschbaum, F.: Reproduction of the weakly electric fishPollimyrus isidori (Mormyridae) in captivity. In preparation (1977c)Google Scholar
  17. Kirschbaum, F., Denizot, J.P.: Sur la différenciation des électrorécepteurs chezMarcusenius sp. etEigenmannia virescens (Gymnotidés), poissons électriques a faible décharge. C. R. Acad. Sci. Paris281, 419–422 (1975)Google Scholar
  18. Kirschbaum, F., Westby, G.W.M.: Development of the electric discharge in mormyrid and gymnotid fish (Marcusenius sp. andEigenmannia virescens). Experientia31, 1290–1293 (1975)Google Scholar
  19. Kramer, B.: Electric organ discharge interaction during interspecific agonistic behaviour in freely swimming mormyrid fish. I. Comp. Physiol.93, 203–235 (1974)Google Scholar
  20. Russel, C.J., Myers, J.P., Bell, C.C.: The echo response inGnathonemus petersii (Mormyridae). J. comp. Physiol.92, 181–200 (1974)Google Scholar
  21. Srivastava, C.B.L., Szabo, T.: Development of electric organs ofGymnarchus niloticus. I. Origin and histogenesis of electroplates. J. Morphol.138, 375–386 (1972)Google Scholar
  22. Srivastava, C.B.L., Szabo, T.: Development of electric organs ofGymnarchus niloticus. II. Formation of spindles. J. Morphol.140, 461–466 (1973)Google Scholar
  23. Szabo, T.: Development of the electric organ of Mormyridae. Nature188, 760–762 (1960)Google Scholar
  24. Szabo, T.: Rapports ontogénétiques entre l'organe électrique, son innervation et sa commande encéphalique (Mormyrus rume). Z. Zellforsch.55, 200–203 (1961)Google Scholar
  25. Taverne, L.: Note sur la systématique des poissons mormyriformes. Le problème des genresGnathonemus GILL,Marcusenius GILL,Hippopotamyrus PAPPENHEIM,Cyphomyrus MYERS et les nouveaux genresPollimyrus etBrienomyrus. Rev. Zool. Bot. Afr.84, 99–110 (1971)Google Scholar
  26. Westby, G.W.M., Boudinot, M., Kirschbaum, F.: Computer assisted detection of discharge onset and development in larvae of the electric fishEigenmannia virescens. In preparation (1977)Google Scholar
  27. Westby, G.W.M., Kirschbaum, F.: Emergence and development of electric organ discharge in the mormyrid fishPollimyrus isidori. II. The adult discharge. Manuscript (1977)Google Scholar
  28. Zipser, B., Bennett, M.V.L.: Interaction of electrosensory and electromotor signals in the lateral line lobe of a mormyrid fish. J. Neurophysiol.39, 713–721 (1976)Google Scholar

Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • G. W. Max Westby
    • 1
  • Frank Kirschbaum
    • 1
  1. 1.Laboratoire de Physiologie Nerveuse, Département de Neurophysiologie SensorielleCentre National de la Recherche ScientifiqueGif-sur-YvetteFrance

Personalised recommendations