Otolith‐Based Age Estimates of Alligator Gar Assessed Using Bomb Radiocarbon Dating to Greater than 60 Years

2019 ◽  
Vol 40 (3) ◽  
pp. 613-621 ◽  
Author(s):  
Daniel J. Daugherty ◽  
Allen H. Andrews ◽  
Nathan G. Smith
Keyword(s):  
Radiocarbon Dating ◽  
Alligator Gar ◽  
Bomb Radiocarbon ◽  
Age Estimates

Great longevity of speckled hind (Epinephelus drummondhayi), a deep-water grouper, with novel use of postbomb radiocarbon dating in the Gulf of Mexico

2013 ◽  
Vol 70 (8) ◽  
pp. 1131-1140 ◽  
Author(s):  
Allen H. Andrews ◽  
Beverly K. Barnett ◽  
Robert J. Allman ◽  
Ryan P. Moyer ◽  
Hannah D. Trowbridge
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Radiocarbon Dating ◽  
Early Growth ◽  
Economic Importance ◽  
Growth Characteristics ◽  
Adult Age ◽  
Bomb Radiocarbon ◽  
Growth Zones ◽  
Age Estimates

Growth characteristics are poorly understood for speckled hind (Epinephelus drummondhayi), a tropical deep-water grouper of economic importance that is considered overfished. Age has been validated for early growth, but the validity of adult age estimates is unknown. A few studies of growth zones in otoliths have revealed maximum age estimates of 15–35 years, which have been uncritically assumed as longevity. To answer questions about adult age, bomb radiocarbon dating was used to provide validated age estimates. A novel aspect of this study was use of the postbomb radiocarbon decline period (ca. 1980–2004) to age younger fish, an approach that was validated with known-age otoliths. Bomb radiocarbon dating provided valid length-at-age estimates ranging from ∼5 years to more than 45 years. Age was unexpectedly greater than previous estimates for more than half the fish used in this study, and longevity may approach 60–80 years. This study extends the utility of bomb radiocarbon dating by more than 20 years and adds to the growing perspective that deep-water tropical fishes can be long-lived.

Refined bomb radiocarbon dating of two iconic fishes of the Great Barrier Reef

2015 ◽  
Vol 66 (4) ◽  
pp. 305 ◽  
Author(s):  
Allen H. Andrews ◽  
John H. Choat ◽  
Richard J. Hamilton ◽  
Edward E. DeMartini
Keyword(s):  
Great Barrier Reef ◽  
Radiocarbon Dating ◽  
Growth Zone ◽  
Barrier Reef ◽  
Hermatypic Coral ◽  
Advanced Technologies ◽  
Bomb Radiocarbon ◽  
Growth Zones ◽  
Bolbometopon Muricatum ◽  
Age Estimates

Refinements to the methodology of bomb radiocarbon dating made it possible to validate age estimates of the humphead wrasse (Cheilinus undulatus) and bumphead parrotfish (Bolbometopon muricatum). Age for these species has been estimated from presumed annual growth zones in otoliths at ~30 and ~40 years respectively. The validity of these estimates was tested using bomb radiocarbon dating on the small and fragile otoliths of these species, and provided an opportunity to refine the method using advanced technologies. A regional Δ14C reference record from hermatypic coral cores from the Great Barrier Reef was assembled and Δ14C measurements from extracted otolith cores of adult otoliths were successful. Validated ages supported the accuracy of growth zone derived ages using sectioned sagittal otoliths.

scholarly journals Bomb radiocarbon dating of three important reef-fish species using Indo-Pacific Δ14C chronologies

2011 ◽  
Vol 62 (11) ◽  
pp. 1259 ◽  
Author(s):  
Allen H. Andrews ◽  
John M. Kalish ◽  
Stephen J. Newman ◽  
Justine M. Johnston
Keyword(s):  
Fish Species ◽  
Age Estimation ◽  
Radiocarbon Dating ◽  
Reef Fishes ◽  
Growth Zone ◽  
Age And Growth ◽  
Thin Sections ◽  
Bomb Radiocarbon ◽  
Reef Fish Species ◽  
Age Estimates

Demersal reef fishes of the Indo-Pacific are under increasing pressure as a fisheries resource, yet many of the important life history characteristics required for suitable management are poorly known. The three fish species, eightbar grouper (Hyporthodus octofasciatus), ruby snapper (Etelis carbunculus) and the spangled emperor (Lethrinus nebulosus), are important components of fisheries and ecosystems throughout the Indo-Pacific. Despite their importance, age and growth information is incomplete. Age has been estimated for E. carbunculus and L. nebulosus, but validated age beyond the first few years is lacking and for H. octofasciatus no age estimates exist. Bomb radiocarbon dating can provide age estimates that are independent of growth-zone counting, but only if appropriate reference Δ14C chronologies exist. In this study, a series of Δ14C records from hermatypic corals was assembled to provide a basis for bomb radiocarbon dating in the western Indo-Pacific region. Results provided (1) valid age estimates for comparison to age estimates from two facilities investigating growth-zones in otolith thin sections; (2) support for age estimation protocols using otolith thin sections; and (3) the information necessary for further refinement of age estimation procedures. Estimates of longevity from bomb radiocarbon dating agree with some prior studies: H. octofasciatus, E. carbunculus and L. nebulosus all being long-lived species with life spans of at least 43, 35 and 28 years respectively.

Bomb radiocarbon dating of the endangered white abalone (Haliotis sorenseni): investigations of age, growth and lifespan

2013 ◽  
Vol 64 (11) ◽  
pp. 1029 ◽  
Author(s):  
Allen H. Andrews ◽  
Robert T. Leaf ◽  
Laura Rogers-Bennett ◽  
Melissa Neuman ◽  
Heather Hawk ◽  
...  
Keyword(s):  
Endangered Species ◽  
Radiocarbon Dating ◽  
Marine Invertebrate ◽  
Extinction Risk ◽  
Predictive Modelling ◽  
Age And Growth ◽  
Large White ◽  
Adult Lifespan ◽  
Bomb Radiocarbon ◽  
The Status

Understanding basic life-history characteristics of white abalone (Haliotis sorenseni), such as estimated lifespan, is critical to making informed decisions regarding the recovery of this endangered species. All predictive modelling tools used to forecast the status and health of populations following restoration activities depend on a validated estimate of adult lifespan. Of the seven Haliotis species in California, white abalone is considered to have the highest extinction risk and was the first marine invertebrate listed as an endangered species under the Federal Endangered Species Act (ESA). Lifespan was previously estimated from observations of early growth; however, no study has generated ages for the largest white abalone. To address questions of age and growth, bomb radiocarbon (Δ14C) dating was used on shells from large white abalone. Measured bomb Δ14C levels were compared to regional Δ14C reference records to provide estimates of age, growth and lifespan. Bomb radiocarbon dating indicated that growth was variable among individuals, with a maximum estimated age of 27 years. The findings presented here provide support for previous age and growth estimates and an estimated lifespan near 30 years. These age data support the perception of a critical need for restoring the remnant aging and potentially senescent population.

scholarly journals CALCINED BONE AS A RELIABLE MEDIUM FOR RADIOCARBON DATING: A TEST USING PAIRED NORTH AMERICAN SAMPLES

2017 ◽  
Vol 82 (3) ◽  
pp. 593-608 ◽  
Author(s):  
James C. Chatters ◽  
James W. Brown ◽  
Steven Hackenberger ◽  
Patrick McCutcheon ◽  
Jonathan Adler
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Radiocarbon Dating ◽  
Bone Collagen ◽  
Organic Media ◽  
Radiocarbon Age ◽  
Cross Dating ◽  
Chronometric Analysis ◽  
Calcined Bone ◽  
Age Estimates

Radiocarbon dating using charcoal and bone collagen, two standards of archaeological chronology, can be difficult to impossible in environments where natural burning is common and bone does not preserve well. In such settings, charcoal ages cannot always be trusted and collagen is unavailable. Calcined bone can be a viable alternative medium in these situations but it has rarely been exploited in the Americas. One area that could benefit from its use is the forested Pacific Northwest. We compare calcined bone ages with charcoal and/or collagen dates from individual features or discrete cultural strata in 10 Washington, Oregon, Idaho, and British Columbia sites dating between 9000 and 100 B.P. Resulting radiocarbon age estimates based on calcined bone closely match those based on charcoal and/or collagen in nearly all cases. We obtained calcined bone dates from three additional Holocene-aged sites that had not previously produced accurate results, obtaining findings consistent with estimates based on cross dating. Preserving well where all other organic media of cultural origin are lost or unreliable, calcined bone holds promise for dating sites in conifer forests and other acidic soil settings, and can allow researchers to refine archaeological sequences that have long defied accurate chronometric analysis.

Age and growth of the white shark, Carcharodon carcharias, in the western North Atlantic Ocean

2015 ◽  
Vol 66 (5) ◽  
pp. 387 ◽  
Author(s):  
Lisa J. Natanson ◽  
Gregory B. Skomal
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
White Shark ◽  
Age And Growth ◽  
Carcharodon Carcharias ◽  
Vertebral Centra ◽  
Bomb Radiocarbon ◽  
History Information ◽  
Age Estimates

Age and growth estimates for the white shark (Carcharodon carcharias) in the western North Atlantic Ocean (WNA) were derived from band pair counts on the vertebral centra of 81 specimens collected between 1963 and 2010. We used two previously published criteria to interpret band pairs and assessed the validity of each method using Δ14C levels from a recent bomb radiocarbon validation study and existing Δ14C reference chronologies in the WNA. Although both criteria produced age estimates consistent, to varying degrees, with different reference chronologies, only one was considered valid when life history information was used to select the appropriate reference chronology and minimum/maximum ages based on bomb carbon values were taken into consideration. These age estimates, validated up to 44 years, were used to develop a growth curve for the species, which was best described using the Schnute general model (sexes combined). These results indicate that white sharks grow more slowly and live longer than previously thought.

Holocene environmental change resets lichen surface dates on Recess Peak glacial deposits in the Sierra Nevada, California

2013 ◽  
Vol 80 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Louis A. Scuderi ◽  
Peter J. Fawcett
Keyword(s):  
Climate Change ◽  
Environmental Change ◽  
Sierra Nevada ◽  
Radiocarbon Dating ◽  
Late Holocene ◽  
Tree Line ◽  
Glacial Deposits ◽  
Present Evidence ◽  
Holocene Environmental Change ◽  
Age Estimates

Development of an accurate chronology for glacial deposits in the Sierra Nevada has long been problematic given the lack of suitable organic material for radiocarbon dating. Lichenometry initially appeared promising as ages showed an increase from cirque headwalls to down-canyon moraines. However, while Recess Peak lichen age estimates range from 2 to 3 ka, recent work shows these deposits to be at least 10 ka older. Here, we present evidence for a late Holocene reset of Recess Peak lichen ages by significant post-depositional climate change. Following late-Pleistocene deposition of Recess Peak moraines, warming through the mid-Holocene allowed forests to advance into shallow basins eliminating local inverted tree lines. This produced a partial canopy where shading killed the original post-Pleistocene crustose lichen colonies. Late-Holocene cooling resulted in forest retreat from these basins as alpine tree line fell. Lichens then recolonized the re-exposed Recess Peak deposits. We conclude that while Recess Peak lichen ages are accurate to within the dating uncertainty of the technique, existing lichen ages actually date the timing of post-mid-Holocene cooling and recolonization, and not the original emplacement of these deposits. Thus, applications of Lichenometry should consider post-depositional environmental change when interpreting the meaning of these dates.

Maximum age and missing time in the vertebrae of sand tiger shark (Carcharias taurus): validated lifespan from bomb radiocarbon dating in the western North Atlantic and southwestern Indian Oceans

2014 ◽  
Vol 65 (8) ◽  
pp. 674 ◽  
Author(s):  
M. S. Passerotti ◽  
A. H. Andrews ◽  
J. K. Carlson ◽  
S. P. Wintner ◽  
K. J. Goldman ◽  
...  
Keyword(s):  
North Atlantic ◽  
Tiger Shark ◽  
Carbon 14 ◽  
Growth Bands ◽  
Bomb Radiocarbon ◽  
Future Work ◽  
Large Adult ◽  
Vertebral Growth ◽  
Age Estimates ◽  
Carcharias Taurus

Bomb radiocarbon analysis of vertebral growth bands was used to validate lifespan for sand tiger sharks (Carcharias taurus) from the western North Atlantic (WNA) and southwestern Indian Oceans (SIO). Visual counts of vertebral growth bands were used to assign age and estimate year of formation (YOF) for sampled growth bands in eight sharks from the WNA and two sharks from the SIO. Carbon-14 results were plotted relative to YOF for comparison with regional Δ14C reference chronologies to assess the accuracy of age estimates. Results from the WNA validated vertebral age estimates up to 12 years, but indicated that ages of large adult sharks were underestimated by 11–12 years. Age was also underestimated for adult sharks from the SIO by 14–18 years. Validated lifespan for C. taurus individuals in the present study reached at least 40 years for females and 34 years for males. Findings indicated that the current age-reading methodology is not suitable for estimating the age of C. taurus beyond ~12 years. Future work should investigate whether vertebrae of C. taurus record age throughout ontogeny, or cease to be a reliable indicator at some point in time.

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