Vertical movement and habitat of opah (Lampris guttatus) in the
central North Pacific recorded with pop-up archival tags |
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Jeffrey J. Polovina, Donald Hawn, Melanie Abecassis |
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| Abstract:
Data from 11 pop-up archival transmitting tags
attached to opah (Lampris guttatus, F. Lampridae) in the
central North Pacific between November 2003 and March
2005 were used to describe their vertical movement and
habitat. In the subtropical gyre northwest of the Hawaiian
Islands, opah generally inhabited a 50–400m depth range
and 8–22ºC temperatures. They were frequently found in
depths of 50–150m at night and in greater depths (100–400m)
during the day, but were constantly moving vertically
within this broad range. At night, excursions below
200m were not uncommon and during the day they were
very likely to spend some time at depths < 175m. Their
vertical speeds were generally < 25cm.s–1 but on one
occasion an opah descended at a burst speed of 4m.s–1.
Vertical habitat use by individual opah apparently varied
with local oceanographic conditions, but over a 24-h period
the average temperature experienced was always in the
narrow range of 14.7 to 16.5ºC.
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