Life history characteristics and status of the Pacific yellowtail emperor, Lethrinus atkinsoni (Seale 1910), in the Commonwealth of the Northern Mariana Islands

Abstract

Abstract Life history characteristics of the Pacific yellowtail emperor, Lethrinus atkinsoni, were described from commercial samples in the Commonwealth of the Northern Mariana Islands spanning a 28‐month market sampling period. Derived statistics pertaining to growth, life span, mortality and reproductive features were obtained through analyses of sectioned sagittal otoliths and gonad tissues. Maximum age observed was 18 years, with females attaining 50% sexual maturity at 3.3 years at a fork length of 20.9 cm; too few male specimens precluded male maturation estimates. We concluded that the species exhibited an undetermined sexual pattern as no evidence of prior female function was observed in mature males. No annual spawning periods were identifiable. Early growth rates estimated by settlement size‐constrained VBGF models using fish landed by the nighttime commercial spear fishery (NCSF) were rapid. Exploitation rates indicated very low‐to‐moderate levels of exploitation. Boat‐based fishing efforts from the NCSF captured the larger individuals of the species, whereas shore‐based efforts captured the vast majority of individuals representing sizes generally below that of the estimated 50% maturation level. Extensive fishery‐independent in situ diver observations indicated the species may have a restricted range. Expanded fishery‐dependent collection of L. atkinsoni specimens and studies of its movement ecology at Saipan would provide additional input for fishery management, as well as a formal stock assessment which juvenile‐biased catches indicate are necessary.

Keywords

• age and growth
• exploitation
• Lethrinidae
• Mariana Islands