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The muscle twitch and the maximum swimming speed of giant bluefin tuna, Thunnus thynnus L.
Author(s) -
Wardle C. S.,
Videler J. J.,
Arimoto T.,
Franco J. M.,
He P.
Publication year - 1989
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1989.tb03399.x
Subject(s) - tuna , thunnus , biology , anatomy , zoology , peduncle (anatomy) , fishery , fish <actinopterygii>
Sustained swimming of bluefin tuna was analysed from video recordings made of a captive patrolling fish school [lengths (L) 1.7–3.3 m, body mass (M) 54–433 kg]. Speeds ranged from 0.6 to 1.2 L s −1 (86–260 km day −1 ) while stride length during steady speed swimming varied between 0.54 and 0.93 L. Maximum swimming speed was estimated by measuring twitch contraction of the anaerobic swimming muscle in pithed fish 5 min after death. Muscle contraction time increased from the shortest just behind the head (30–50 ms at 20% L) to the longest at the tail peduncle (80–90 ms at 80% L) (all at 28°C). A fish (L = 2.26 m) with a muscle contraction time of 50 ms at 25% L can have a maximum tail beat frequency of 10 Hz and maximum swimming speed of 15m s −1 (54km h −1 ) with a stride length of 0.65L. With a stride length of 1 L a speed of 22.6 m s −1 (81.4 km h −1 ) is possible. Power used at maximum speed was estimated for this fish at between 10 and 40 kW, with corresponding values for the drag coefficient at a Reynolds number of 4.43 × 10 7 of 0.0007 and 0.0027.