Comparative age-specific demography of four commercially important deepwater snappers: Implication for fishery management of a long-lived lutjanid.

Lutjanid snappers belonging to the subfamilies Apsilinae and Etelinae are commercially valuable components of tropical deepwater fisheries throughout much of the Indo-Pacific region. Based on age assessment using sagittal otoliths, the age-specific demographic characteristics of four deepwater snappers, Eteis coruscans, Paracaesio caerulea, Pristipomoides filamentosus, and Pristipomoides sieboldii, in the Okinawa Islands, southwestern Japan, were examined, and the results were discussed for fishery management. Age validation using edge-type analysis demonstrated that opaque zones in all species were formed once per year and were considered valid annual growth increments. The von Bertalanffy growth equations were also determined for each species. These snappers are long-lived (>50 years for E. coruscans and P. caerulea and > 30 years for the two species of Pristipomoides) and relatively slow-growing. The age of acquiring sexual maturity in females was relatively later in E. coruscans, P. caerulea, and P. filamentosus than in P. sieboldii. The results revealed differences in the biological traits among these four species; E. coruscans and P. caerulea with long lifespans and late maturation are particularly more vulnerable to fishing impact than the two Pristipomoides species. We therefore recommend that further approaches to decrease and control fishing intensity, such as networking of marine protected areas and regulation to control the numbers of boats and/or the total allowable catch, are necessary for management of the stock of these species, especially for E. coruscans and P. caerulea. This article is protected by copyright. All rights reserved.