Evaluating the performance of otolith morphometrics in deriving age compositions and mortality rates for assessment of data-poor tropical fisheries
MetadataShow full item record
© International Council for the Exploration of the Sea 2015. All rights reserved.Deepwater snappers (Family Lutjanidae) are important to artisanal and subsistence fisheries in Pacific Island countries. Most species of deepwater snapper are considered vulnerable to exploitation due to their extended longevity and low natural mortality rates. However, the sustainability of deepwater snapper fisheries in Pacific Island countries remains uncertain because there are limited resources available to collect the required data for comprehensive stock assessments. Reliable estimates of the age composition for exploited deepwater snapper populations are limited primarily because of the lack of skills and resources required for routine age estimation from sectioned otoliths. The development of alternative low-cost approaches to derive estimates of age for deepwater snappers is required. We evaluated the performance of using otolith morphometrics (weight, length, width, and thickness) to obtain estimates of age for the most important target species in these fisheries: Etelis carbunculus, E. marshi, E. coruscans, and Pristipomoides filamentosus. We compared age compositions and fishing mortality rates (F) derived from otolith morphometrics with those derived from counts of annual increments in otoliths. We then used the ratio of F to natural mortality (M) as a biological indicator to evaluate the potential effects on management responses by comparing estimates of F/M derived from otolith morphometrics with those derived from annual increment counts. Age compositions and estimates of F and F/M did not differ significantly between those derived from otolith morphometrics and those derived from annual increment counts for all species. These results demonstrate that management responses would likely be similar whether based on age estimates derived from sectioned otoliths, or predicted from otolith morphometrics. In the absence of sufficient resources to section otoliths for age estimation, we recommend that otolith morphometrics be used as a proxy for age in assessments of deepwater snapper fisheries in Pacific Island countries, and potentially for other similar data-limited fisheries.
Showing items related by title, author, creator and subject.
Ageing bias and precision for deep-water snappers: evaluating nascent otolith preparation methods using novel multivariate comparisons among readers and growth parameter estimatesWakefield, Corey; O'Malley, J.; Williams, A.; Taylor, B.; Nichols, R.; Halafihi, T.; Humphreys, R.; Kaltavara, J.; Nicol, S.; Newman, Stephen (2017)Tropical deep-water snappers (Etelinae) support valuable fisheries across the Indo-Pacific, with stock assessments reliant on age-based information in the absence of reliable catch and effort statistics. These long-lived ...
Oceanic, latitudinal, and sex-specific variation in demography of a tropical deepwater snapper across the indo-pacific regionWilliams, A.; Wakefield, Corey; Newman, Stephen; Vourey, E.; Abascal, F.; Halafihi, T.; Kaltavara, J.; Nicol, S. (2017)Deepwater tropical fisheries provide an important source of income and protein to Pacific and Indian Ocean coastal communities who are highly dependent on fish for food security. The development of quantitative assessments ...
Parsons, Miles James Gerard (2009)Techniques of single- and multi-beam active acoustics and the passive recording of fish vocalisations were employed to evaluate the benefits and limitations of each technique as a method for assessing and monitoring fish ...