The Biology of the Marquesan Sardine, Sardinella marquesensis

Abstract

Data and samples obtained in the Marquesas Islands from 1954 to 1960 form the basis of this report. Various morphological traits of the Marquesan sardine, Sardinella marquesensis, are described, and measures of their variation are given . These sardines were found mostly in bays with clear to slightly turbid and clear-green to brownish-green water and with substrate of sand, rock, coral rubble, or a combination of these. The composition of their stomach contents was very similar to that of plankton obtained in sardine habitats. Ten of the 35 species of fish taken with sardines in the seine are probable predators of the latter. Sardine behavior in the field, in captivity, and as tuna bait is noted. Parasites included hemiurid trematodes, camallanid nematodes, and an ergasilid copepod. Attainment of sexual maturity is estimated at a standard length of 84 mm. Spawning is believed to occur throughout the year. Between 1,000 and 8,000 ova are deposited at a single spawning. The sex ratio favored males. The abundance of Marquesan sardines appears to be inadequate to sustain commercial live-bait tuna vessels like those operating from California ports.