Size-selective mortality of inland silversides: Evidence from otolith microstructure

Size-selective mortality of age-0 inland silversides Menidia beryllina was assessed by using otolith microstructure analysis and the biological intercept back-calculation procedure. Back-calculated size-frequency distributions were compared with the size-frequency distributions of field collections to determine if and when size-selective mortality occurred. These analyses indicated that in both 1990 and 1992, size-selective mortality occurred and was directed at the larger members of the inland silverside cohort. The timing of size-selective mortality varied between the 2 years. In 1990, size-selective mortality occurred during the juvenile stage, whereas in 1992, size-selective mortality occurred during the]ate larval and early juvenile stages. These results conflict with the prevailing hypothesis that larger individuals have higher survival probabilities than smaller individuals but support our previous finding that juvenile bluefish Pomatomus saltatrix prefer to prey on the larger members of the inland silverside cohort.