Premium
DIEL PATTERNS IN AGGREGATIONS OF PELAGIC DOLPHINS AND TUNAS IN THE EASTERN PACIFIC
Author(s) -
Scott Michael D.,
Cattanach Karen L.
Publication year - 1998
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/j.1748-7692.1998.tb00735.x
Subject(s) - diel vertical migration , pelagic zone , predation , yellowfin tuna , fishery , tuna , biology , thunnus , geography , ecology , fish <actinopterygii>
A bstract Data collected by scientific technicians aboard tuna purse seiners in the eastern Pacific Ocean since the early 1970s have allowed us to study the biology and herd dynamics of pelagic dolphins. A pattern of increasing group size in the morning and subsequent decline in the late afternoon or night was evident for spotted, spinner, and common dolphins, as well as for large yellowfin tuna that associate with dolphins. Diel patterns were also apparent in the formation of mixed‐species herds of spotted and spinner dolphins and tuna‐dolphin aggregations. Different patterns, however, were displayed by bottlenose dolphins and by yellowfin and skipjack tunas that did not associate with dolphins. It appears that these diel patterns are produced by an interaction of predation pressure and prey distribution.