Effects of exploitation evident in age-based demography of 2 deepwater snappers, the goldeneye jobfish (Pristipomoides flavipinnis) in the Samoa Archipelago and the goldflag jobfish (P. auricilla) in the Mariana Archipelago

• Published in: Fishery bulletin (Washington, D.C.) Vol. 117; no. 4; pp. 322 - 336
• Main Authors: O’Malley, Joseph M., Wakefield, Corey B., Oyafuso, Zack S., Nichols, Ryan S., Taylor, Brett, Williams, Ashley J., Sapatu, Maria, Marsik, Michael
• Format: Journal Article
• Language: English
• Published: Washington Superintendent of Documents 01.01.2019
• Subjects: Age; Aquatic birds; Archipelagoes; Catch per unit effort; Deep water; Demography; Exploitation; Fishing; Fishing effort; Fishing pressure; Growth; Lutjanidae; Marine fishes; Mortality; Natural mortality; Pristipomoides auricilla; Pristipomoides flavipinnis; Stock assessment; Total mortality; Waterfowl; Samoa
• ISSN: 0090-0656; 1937-4518
• DOI: 10.7755/FB.117.4.5

The paucity of speciesspecific biological information for most exploited Indo-Pacific deepwater snappers (Lutjanidae) limits stock assessment options and management strategies. To improve stock assessments, age-based demographics were estimated for 2 deepwater snapper species, the goldeneye jobfish (Pristipomoides flavipinnis) in the Samoa Archipelago and the goldflag jobfish (P. auricilla) in the Mariana Archipelago. Each archipelago has locations where fishing had not occurred for at least 30 years, providing a rare opportunity to examine the effects of exploitation on the age and size compositions, growth, and mortality of these species. Overall, age-based data reveal a greater effect of fishing pressure than those based on size. This difference highlights concerns with size-based analyses; when species have protracted asymptotic growth trajectories, the resulting fishing impacts may not be readily apparent in size-based analyses because size and age become decoupled. This decoupling also confounds comparisons of growth among areas with different exploitation levels. Mortality estimates derived from an age-based catch curve for the unfished areas (where total mortality equals natural mortality) were comparable to those produced by using a maximumage-based natural mortality estimator. The comparison of these methods indicates that the age-based natural mortality estimator is suitable for use in deepwater snapper stock assessments when direct measures of natural mortality are unavailable.