Skip to main content

An acoustic tracking of a megamouth shark, Megachasma pelagios: a crepuscular vertical migrator

Abstract

A 4.9 m TL megamouth shark, only the sixth specimen known to science, was tracked continuously for 50.5 h, during which it exhibited distinct vertical migrations at the dawn and dusk transitions. The male shark was captured on 21 October 1990 in a drift gill net off Dana Point, California, restrained overnight in a harbor, and released at sea the next afternoon. Horizontally, the shark moved slowly southward, covering 62 km on a relatively straight path with no significant diel changes. For the major part of the tracking, its rate of movement was 1.15 km h−1, as determined from positions at 15 min intervals. Considering a probable head current of 10–25 cm sec−1, its estimated through-the-water swimming speed was more likely 1.5–2.1 km h−1 (X¯ = 1.8, representing 0.1 body lengths sec−1). Vertically, the shark stayed shallow at night (12–25 m depth range, X¯ = 17) and deep during the days (120–166 m, X¯ = 149) but still well above the bottom at 700–850 m. The four twilight depth-change events were very distinct and always spanned the times of sunset or sunrise. The ascent and descent profiles are a reasonble match to isolumes on the order of 0.4 lux for an extinction coefficient (0.07) calculated from water transparency measurements. Furthermore, the steepest parts of the shark's profiles correspond closely to the times of maximum rate-of-change of illumination. These findings suggest that, except during nights, the shark's chosen depth was to a large degree determined by light level.

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

References cited

  • Bakus, G.J. 1989. The marine biology of southern California. Occasional Papers, Allan Hancock Foundation, Univ. of Southern California, New Series 7, 61 pp.

  • Beck, S.D. 1980. Insect photoperiodism. Academic Press, New York. 387 pp.

    Google Scholar 

  • Berra, T.M. & J.B. Hutchins. 1990. A specimen of megamouth shark, Megachasma pelagios (Megachasmidae) from Western Australia. Rec. West. Aust. Mus. 14: 651–656.

    Google Scholar 

  • Berra, T.M. & J.B. Hutchins. 1991. Natural history notes on the megamouth shark, Megachasma pelagios, from Western Australia. West. Aust. Naturalist. 18: 224–233.

    Google Scholar 

  • Brinton, E. 1962. The distribution of Pacific euphausids. Bull. Scripps Inst. Oceanogr. 8: 51–269.

    Google Scholar 

  • Brown, J., A. Colling, D. Park, J. Phillips, D. Rothery & J. Wright. 1989. Seawater: its composition, properties and behaviour. Oceanography Series of The Open University. Pergamon Press, Oxford. 165 pp.

    Google Scholar 

  • Carey, F.G. & E. Clark. 1995. Depth telemetry from the sixgill shark, Hexanchus griseus, at Bermuda. Env. Biol. Fish. 42: 7–14.

    Google Scholar 

  • Carey, F.G. & J.V. Scharold. 1990. Movements of blue sharks (Prionace glauca) in depth and course. Mar. Biol. 106: 329–342.

    Google Scholar 

  • Carey, F.G. & G.H. Robison. 1981. Daily patterns in the activities of swordfish, Daily patterns in the activities of swordfish, \(\bar Xiphias\) gladius, observed by acoustic telemetry. U.S. Fish. Bull. 79: 277–292.

    Google Scholar 

  • Carey, F.G., J.W. Kanwisher, O. Brazier, G. Gabrielson, J.G. Casey & H.L. Pratt, Jr. 1982. Temperature and activities of a white shark, Carcharodon carcharias. Copeia 1982: 254–260.

    Google Scholar 

  • Clark, E. & J.I. Castro. 1995. ‘Megamama’ is a virgin: dissection of the first female specimen of Megachasma pelagios. Env. Biol. Fish. 43: 329–332.

    Google Scholar 

  • Compagno, L.J.V. 1990. Relationships of the megamouth shark, Megachasma pelagios (Lamniformes: Megachasmidae) with comments on its feeding habits. pp. 357–379. In: H.L. Pratt Jr., S.H. Gruber & T. Taniuchi (ed.) Elasmobranchs as Living Resources, NOAA Tech. Rep. NMFS 90.

  • Finstad, W.O. & D.R. Nelson. 1975. Circadian activity rhythm in the horn shark, Heterodontus francisci: effect of light intensity. Bull. S. Calif. Acad. Sci. 74: 20–26.

    Google Scholar 

  • Forward, R.B., Jr. 1987. Crustacean larval vertical migration: a perspective. pp. 29–44. In: W.F. Herrnkind & A.B. Thistle (ed.) Signposts in the Sea, Florida State University, Tallahassee.

    Google Scholar 

  • Gruber, S.H., D.R. Nelson & J.F. Morrissey. 1988. Patterns of activity and space utilization of lemon sharks, Negaprion brevirostris, in a shallow Bahamian lagoon. Bull. Mar. Sci. 43: 61–76.

    Google Scholar 

  • Harden Jones, F.R. 1973. Tail beat frequency, amplitude, and swimming speed of a shark tracked by sector scanning sonar. J. Cons. int. Explor. Mer. 35: 95–97.

    Google Scholar 

  • Hickey, B.M. 1992. Circulation over the Santa Monica-San Pedro Basin and Shelf. Prog. Oceanog. 30: 37–115.

    Google Scholar 

  • Holland, K.N., R.W. Brill & R.K.C. Chang. 1990. Horizontal and vertical movements of yellowfin and bigeye tuna associated with fish aggregating devices. U.S. Fish. Bull. 88: 493–507.

    Google Scholar 

  • Klimley, A.P. 1993. Highly directional swimming by scalloped hammerhead sharks, Sphyrna lewini, and subsurface irradiance, temperature, bathymetry, and geomagnetic field. Mar. Biol. 117: 1–22.

    Google Scholar 

  • Landesman, J.G. 1984. Horizontal and vertical movements and seasonal population shifts in the blue shark, Prionace glauca, near Santa Catalina Island, California. M.S. Thesis, California State University, Long Beach. 79 pp.

    Google Scholar 

  • Lavenberg, R.J. 1991. Megamania — the continuing saga of megamouth sharks. Terra 30(1): 30–39.

    Google Scholar 

  • Lavenberg, R.J. & J.A. Seigel. 1985. The Pacific's megamystery — megamouth. Terra 23(4): 29–31.

    Google Scholar 

  • Miya, M., M. Hirosawa & K. Mochizuki. 1992. Occurrence of a megamouth. Terra 23(4): 29–31.

    Google Scholar 

  • Miya, M., M. Hirosawa & K. Mochizuki. 1992. Occurrence of a megachasmid shark in Suruga Bay: photographic evidence. J. Nat. Hist. Mus. Inst., Chiba 2: 41–44.

    Google Scholar 

  • Nakaya, K. 1989. Discovery of megamouth shark from Japan. Japan. J. Ichthyol. 36: 144–146.

    Google Scholar 

  • Nielsen, E.T. 1963. Illumination at twilight. Oikos 14: 9–21.

    Google Scholar 

  • Priede, I.G. 1984. A basking shark (Cetorhinus maximus) tracked by satellite together with simultaneous remote sensing. Fish. Res. 1984: 201–216.

    Google Scholar 

  • Stearns, D.E. & R.B. Forward, Jr. 1984. Copepod photobehavior in a simulated natural light environment and its relation to nocturnal vertical migration. Mar. Biol. 82: 91–100.

    Google Scholar 

  • Strong, W.R., Jr., R.C. Murphy, B.D. Bruce & D.R. Nelson. 1992. Movements and associated observations of bait-attracted white sharks, Carcharodon carcharias: a preliminary report. Aust. J. Mar. Freshwater Res. 43: 13–20.

    Google Scholar 

  • Taylor, L.R., L.J.V. Compagno & P.J. Struhsaker. 1983. Megamouth — a new species, genus, and family of lamnoid shark (Megachasma pelagios, family Megachasmidae) from the Hawaiian Islands. Proc. Calif. Acad. Sci. 43(8): 87–110.

    Google Scholar 

  • Tricas, T.C., L.R. Taylor & G. Naftel. 1981. Diel behavior of the tiger shark, Galeocerdo cuvier, at French Frigate Shoals, Hawaiian Islands. Copeia 1981: 904–908.

    Google Scholar 

  • Weihs, D. 1977. Effects of size on sustained swimming speeds of aquatic organisms. pp. 333–338. In: T. J. Pedley (ed.) Scale Effects in Animal Locomotion, Academic Press, New York.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Nelson, D.R., McKibben, J.N., Strong, W.R. et al. An acoustic tracking of a megamouth shark, Megachasma pelagios: a crepuscular vertical migrator. Environmental Biology of Fishes 49, 389–399 (1997). https://doi.org/10.1023/A:1007369619576

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1023/A:1007369619576

  • Megachasmidae
  • ultrasonic telemetry
  • diel behavior