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Beyond the average: Diverse individual migration patterns in a population of mesopelagic jellyfish
Author(s) -
Kaartvedt Stein,
Titelman Josefin,
Røstad Anders,
Klevjer Thor A.
Publication year - 2011
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.2011.56.6.2189
Subject(s) - diel vertical migration , jellyfish , mesopelagic zone , population , dusk , echo sounding , range (aeronautics) , plankton , oceanography , mode (computer interface) , environmental science , water column , biology , ecology , geology , demography , pelagic zone , materials science , sociology , computer science , composite material , operating system
We examined the diel behavior among the jellyfish Periphylla periphylla in Lurefjorden, Norway in a sampling campaign and by a > 3‐month continuous acoustic study. Jellyfish distribution and behavior were recorded by an upward‐facing, bottom‐mounted echo sounder at 280‐m depth. The population was typically divided into four groups, each with different behavior. Individuals of behavioral Mode 1 undertook synchronous diel vertical migrations (DVM) within the upper 100 m. Individuals of behavioral Mode 2, stayed at ~ 160‐200‐m depth during the day, and also exhibited synchronized DVM, ascending at dusk and descending at dawn. The smaller individuals of behavioral Mode 3 swam continuously up and down throughout both day and night, yet occurred below Mode 2 individuals in daytime (~ 200 m‐bottom), while their vertical range encompassed the entire water column during night. Mode 4 behavior was displayed by large jellyfish located between ~ 130 m and the bottom. These animals shifted between remaining motionless and relocating in rapid steps during both day and night. These four main behavioral patterns persisted throughout the registration period, although the synchronously migrating Mode 2 behavior became weaker in spring. This acoustic study has unveiled more diverse migration behaviors than previously derived from net sampling and remote‐operated vehicles methods and emphasizes the importance of studying individuals. DVM is complex because individuals in a plankton population may simultaneously engage in a range of various contrasting behaviors.