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Observations of gulls foraging on beach‐stranded plankton in Otago Harbor, New Zealand
Author(s) -
McClatchie S.,
Jillett J. B.,
Gerring P.
Publication year - 1991
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1991.36.6.1195
Subject(s) - foraging , fishery , population , plankton , biology , shore , ecology , geography , oceanography , geology , demography , sociology
Red‐billed gulls ( Larus scopulinus ) and southern black‐backed gulls ( Larus dominicanus ) exploited a large and highly visible food source provided by beaching of euphausiids ( Nyctiphanes australis ) and galatheid crab larvae ( Munida gregaria ) in Otago Harbor. The plankton strandings occurred predominantly in summer, and provided a food source of ∼270 t dry weight over 170 d along 12 km of shoreline. The largest strands (formed by M. gregaria) covered > 10 ha each, and attracted flocks of > 1,500 gulls for up to 2 d. Gull density was positively correlated with the biomass of strandings, and gull population size in the harbor increased during the peak period of stranding events.