scholarly journals Laser ablation–accelerator mass spectrometry reveals complete bomb 14C signal in an otolith with confirmation of 60-year longevity for red snapper (Lutjanus campechanus)

2019 ◽  
Vol 70 (12) ◽  
pp. 1768 ◽  
Author(s):  
Allen H. Andrews ◽  
Christiane Yeman ◽  
Caroline Welte ◽  
Bodo Hattendorf ◽  
Lukas Wacker ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Gulf Of Mexico ◽  
Accelerator Mass Spectrometry ◽  
Red Snapper ◽  
Age And Growth ◽  
Lutjanus Campechanus ◽  
Age Validation ◽  
14C Dating ◽  
Marine Surface Layer

Bomb-produced 14C has been used to make valid estimates of age for various marine organisms for 25 years, but fish ages that lead to birth years earlier than the period of increase in 14C lose their time specificity. As a result, bomb 14C dating is limited to a minimum age from the last year of prebomb levels because the temporal variation in 14C in the marine surface layer is negligible for decades before c. 1958. The longevity of red snapper (Lutjanus campechanus) in the Gulf of Mexico remains unresolved despite various forms of support for ages near 50–60 years. Although the age and growth of red snapper have been verified or validated to a limited extent, some scepticism remains about longevity estimates that exceed 30 years. In this study, red snapper otoliths were analysed for 14C using a novel laser ablation–accelerator mass spectrometry technique to provide a continuous record of 14C uptake. This approach provided a basis for age validation that extends beyond the normal limits of bomb 14C dating with confirmation of a 60-year longevity for red snapper in the Gulf of Mexico.

Red Snapper: Ecology and Fisheries in the U.S. Gulf of Mexico

2007 ◽  
Keyword(s):  
Gulf Of Mexico ◽  
Growth Model ◽  
Fisheries Management ◽  
Red Snapper ◽  
Age And Growth ◽  
Von Bertalanffy ◽  
Lutjanus Campechanus ◽  
History Of ◽  
Von Bertalanffy Growth Model ◽  
The U.S

<em>Abstract.</em>—The red snapper, <em>Lutjanus campechanus</em>, is one of the most economically important fish species in the Gulf of Mexico (GOM). Concerns over the declines in red snapper landings during the 1980s in the GOM exposed the paucity of information regarding the species’ age, growth, and population dynamics, all fundamental in fisheries management. This paper reviews the history of red snapper age and growth research in the GOM demonstrating an evolution of fisheries aging and validation techniques. These refinements in aging over time have also impacted management of the red snapper stock in the GOM. Also discussed are efforts to standardize aging techniques throughout the GOM in an effort to improve data accuracy. A number of studies have used the von Bertalanffy growth model to describe a pattern of rapid growth followed by slower growth after the age of ten years for red snapper in the GOM. Additional applications of the von Bertalanffy growth model have also been applied to corroborate red snapper age estimates derived from sectioned otoliths and to discern demographic differences in red snapper growth throughout the GOM.

scholarly journals Regional differences in the age and growth of red snapper (Lutjanus campechanus) in the U.S. Gulf of Mexico

2014 ◽  
Vol 112 (4) ◽  
pp. 261-273 ◽  
Author(s):  
Courtney R. Saari ◽  
James H. Cowan Jr. ◽  
Kevin M. Boswell
Keyword(s):  
Gulf Of Mexico ◽  
Regional Differences ◽  
Red Snapper ◽  
Age And Growth ◽  
Lutjanus Campechanus ◽  
The U.S

Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives

2018 ◽  
Keyword(s):  
Standard Deviation ◽  
Gulf Of Mexico ◽  
Fisheries Management ◽  
Artificial Reef ◽  
Growth Patterns ◽  
Red Snapper ◽  
Age And Growth ◽  
Artificial Reefs ◽  
Lutjanus Campechanus ◽  
Management Objectives

<em>Abstract</em>.—Identifying morphometrics, age composition, and growth of Red Snapper <em>Lutjanus campechanus </em>(Poey, 1860) in the Gulf of Mexico is crucial for management of this valuable species. Red Snapper are highly associated with artificial reefs situated off the coast of Texas. Artificial reefs, two in federal waters (offshore) and two in state waters (inshore), were sampled quarterly from December 2014 through December 2016. Characteristic differences in age and growth patterns at inshore and offshore sites and across sampled sites were compared. Mean ± standard deviation was calculated for total length (TL), weight, and biological age. Red Snapper collected averaged 464.5 ± 92.6 mm in TL, 1.62 ± 1.03 kg, and 3.8 ± 1.5 years. Significant differences in TL, weight, and age were observed across sites but not between inshore and offshore locations. In comparing 12 previous Red Snapper length-at-age (0–25 years) studies across the Gulf of Mexico, results were similar except for two studies significantly different from one another, but none with respect to our study. Our findings suggest that Red Snapper populations are young and restricted to one or two spawning years before capture on artificial reefs. Continued management of fisheries associated with these reefs are necessary to increase the stock and eventually lead to robust and sustainable fisheries.

scholarly journals Linear decline in red snapper (Lutjanus campechanus) otolith Δ14C extends the utility of the bomb radiocarbon chronometer for fish age validation in the Northern Gulf of Mexico

2018 ◽  
Vol 75 (5) ◽  
pp. 1664-1671 ◽  
Author(s):  
Beverly K Barnett ◽  
Laura Thornton ◽  
Robert Allman ◽  
Jeffrey P Chanton ◽  
William F Patterson
Keyword(s):  
Gulf Of Mexico ◽  
Red Snapper ◽  
Lutjanus Campechanus ◽  
Age Validation ◽  
Data Set ◽  
Northern Gulf Of Mexico ◽  
Significant Difference ◽  
Bomb Radiocarbon ◽  
Relationship Of ◽  
Age Estimates

Abstract Radiocarbon (Δ14C) was analyzed in northern Gulf of Mexico (nGOM) red snapper (Lutjanus campechanus) otolith cores (n = 23), otolith edge samples (n = 12), and whole age-0 otoliths (n = 9), with edge samples and whole age-0 otoliths constituting known-age samples. There was no significant difference in the linear relationship of Δ14C versus year of formation between regional corals and known-age otolith samples, and a linear regression fit to the combined data from 1980 to 2015 extends the utility of the bomb radiocarbon chronometer for age validation. The entire regional coral and known-age otolith data set (1940 to 2015) was then utilized as a reference series to validate otolith-derived red snapper age estimates for cored otolith samples. A loess regression was fit to the reference data and then the sum of squared residuals (SSR) was computed from predicted versus observed birth years for cored adult otolith samples. This process was then repeated for ages biased ±1–4 years. Ages with no bias applied had the lowest SSR, thus validating red snapper age estimates and demonstrating the utility of the combined regional coral and known-age red snapper otolith Δ14C time series for age validation of nGOM marine fishes.

Red Snapper: Ecology and Fisheries in the U.S. Gulf of Mexico

2007 ◽  
Keyword(s):  
Gulf Of Mexico ◽  
Fork Length ◽  
Red Snapper ◽  
Minimum Size ◽  
Minimum Length ◽  
Commercial Fishing ◽  
Lutjanus Campechanus ◽  
Commercial Harvest ◽  
Length Regulation ◽  
The U.S

<em>Abstract.</em>—Red snapper <em>Lutjanus campechanus </em>were sampled from commercial landings from the Gulf of Mexico (GOM) off Louisiana from October 2001 to May 2004. Fork length (FL), eviscerated weight, otoliths (both sagittae), and sex determinations were taken from 2,900 specimens; FL was subsequently converted to total length (TL) with the equation TL = 1.073 (FL) + 3.56. Red snapper ages (<EM>N </EM>= 2,867) estimated from counts of opaque annuli in otoliths ranged from 1 to 14 years; however, the vast majority (97.7%) of these were ages 2 to 6 years and the modal age was 3 years. Total lengths among 2,897 specimens ranged from 278 to 940 mm, modal TL was 400 mm, and 98% of all specimens were less than 600 mm TL. We also investigated the fate of red snapper regulatory discards (individuals <381 mm [15 in] TL) during 16 trips on working commercial vessels; over two-thirds of 4,839 red snapper assigned among four discard fate categories (ranging from alive and vigorous to dead) were returned to the water either in moribund or dead condition. Among 399 potential discards retained for age and length analyses, 86% were between 12 and 15 in (305–381 mm) TL and 85% were 2 years of age. The minimum size regulation appears to do little to protect juvenile red snapper from commercial fishing mortality. Heavy red snapper mortality, which begins as bycatch mortality in shrimp trawls, continues as discard mortality at sub-legal lengths when they first recruit to the offshore fishing grounds, and persists as harvest mortality among the youngest legal year- and size-classes. If the minimum size limit is intended to provide a respite from such mortality, a reconsideration of the utility of the minimum length regulation in the commercial harvest of red snapper may be warranted.

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