Aspects of estuarine intertidal ecology of juvenile striped mullet, Mugil cephalus, in Hawaii

Journal Article · Sat Apr 01 04:00:00 EST 1978 · Fish. Bull.; (United States)

OSTI ID:6695089

Major, P F

Behavior and distribution of schools of young striped mullet, Mugil cephalus, were examined in the field and laboratory. Prejuvenile fish approximately 20 mm standard length leave the open ocean to enter intertidal estuarine regions, where they select the shallowest water, areas with extensive diel temperature and salinity fluctuations. At about 50 mm standard length, the mullet move into deeper intertidal waters. It is at this size that mullet are thought to have completed their metamorphosis to juveniles. In a vertical thermal gradient, fish generally <50 mm standard length selected final mean temperatures of 30.0 to 32.4/sup 0/C at the salinities tested (0, 15, 34/sup 0///sub 00/). In the field, they were found in water with high (34.0 to 37.2/sup 0/C), often near lethal (39.0 to 42.5/sup 0/C) temperatures in shallow pools with salinities of 2 to 30/sup 0///sub 00/. Juveniles generally >50 mm experimentally selected final mean temperatures of 29.0/sup 0/C at 34/sup 0///sub 00/ salinity to 19.5/sup 0/C at 0/sup 0///sub 00/ salinity. In the field, fish > or = to 50 mm remained seaward of the tide line in water of lower and more uniform temperature and higher and more uniform salinity than those recorded for mullet <50 mm. Mullet <50 mm occur seasonally when there are a maximum number of low tides < or = to 0.0 mm and a minimum number of high tides > or = to 0.6 m. This allows the mullet increased time to feed undisturbed in areas where there are no predators and intraspecific and possible interspecific competitors for food and space. By the time fish reach 50 mm standard length, the tidal situation changes, allowing predators and competitors access to the shallow areas during low tide. When in the presence of predators, the schooling habit increases chances of survival for individual mullet.

• Research Organization: Univ. of California, Santa Cruz
• OSTI ID: 6695089
• Journal Information: Fish. Bull.; (United States), Journal Name: Fish. Bull.; (United States) Vol. 76:2; ISSN FSYBA
• Country of Publication: United States
• Language: English

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ANIMALS
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