scholarly journals Bomb dating and age determination of large pelagic sharks

2002 ◽  
Vol 59 (3) ◽  
pp. 450-455 ◽  
Author(s):  
Steven E Campana ◽  
Lisa J Natanson ◽  
Sigmund Myklevoll
Keyword(s):  
Age Determination ◽  
Shark Species ◽  
Apex Predators ◽  
Age Validation ◽  
Growth Band ◽  
Shortfin Mako ◽  
Growth Bands ◽  
Bomb Radiocarbon ◽  
The 1960S ◽  
Vertebral Growth

Despite their notoriety and role as apex predators, the longevity of large pelagic sharks such as the porbeagle (Lamna nasus) and shortfin mako (Isurus oxyrinchus) is unknown. Vertebral growth bands provide an accurate indicator of age in young porbeagle, but age validation has never been reported for any large shark species past the age of sexual maturity. Here, we report the first application of bomb radiocarbon as an age validation method for long-lived sharks based on date-specific incorporation of radiocarbon into vertebral growth bands. Our results indicate that porbeagle vertebrae recorded and preserved a bomb radiocarbon pulse in growth bands formed during the 1960s. Through comparison of radiocarbon assays in young, known-age porbeagle collected in the 1960s with the corresponding growth bands in old porbeagle collected later, we confirm the validity of porbeagle vertebral growth band counts as accurate annual age indicators to an age of at least 26 years. The radiocarbon signatures of porbeagle vertebral growth bands appear to be temporally and metabolically stable and derived mainly from the radiocarbon content of their prey. Preliminary radiocarbon assays of shortfin mako vertebrae suggest that current methods for determining shortfin mako age are incorrect.

scholarly journals Bomb dating, age validation and quality control of age determinations of monodontids and other marine mammals

2014 ◽  
Vol 8 ◽  
Author(s):  
Steven E Campana ◽  
Robert EA Stewart
Keyword(s):  
Quality Control ◽  
Marine Mammals ◽  
Age Determination ◽  
Age Validation ◽  
Age Bias ◽  
Bomb Radiocarbon ◽  
Control Protocols ◽  
The 1960S ◽  
Age Determinations

Methods for confirming the accuracy of age determination methods are reasonably well established in fishes, but the millions of routine age determinations which take place every year require their own quality control protocols. In contrast, methods for ensuring accuracy in age determination of monodontids and other marine mammals are still being developed. Here we review the basis and application of bomb radiocarbon to marine mammal age validation, highlighting its value for providing unambiguous estimates of age for belugas and other long-lived animals which form growth bands. Bomb radiocarbon is particularly useful for marine mammals, given that the age of an individual animal can be determined to within ±1-3 years, as long as it was alive during the 1960s. However, ongoing age determinations require careful monitoring to ensure that age interpretations remain consistent across ages and through time. Quality control protocols using reference collections of ageing material, in conjunction with age bias plots and measures of precision, are capable of detecting virtually all of the systematic ageing errors that often occur once age determinations of an animal become routine.

Assessing growth band counts from vertebrae and dorsal-fin spines for ageing sharks: comparison of four methods applied to Heterodontus portusjacksoni

2009 ◽  
Vol 60 (9) ◽  
pp. 898 ◽  
Author(s):  
Javier Tovar-Ávila ◽  
Christopher Izzo ◽  
Terence I. Walker ◽  
J. Matías Braccini ◽  
Robert W. Day
Keyword(s):  
Shark Species ◽  
Systematic Bias ◽  
Age Validation ◽  
Growth Band ◽  
Dorsal Fin ◽  
Growth Bands ◽  
Visible Growth ◽  
Port Jackson ◽  
First Time ◽  
Fin Spines

Four methods for counting growth bands using vertebrae and dorsal-fin spines of the Port Jackson shark, Heterodontus portusjacksoni, are compared. Both calcified structures presented observable growth bands, allowing cross comparison among structures for the first time in a shark species. Whole and sectioned vertebrae and dorsal fin-spines possess highly visible growth bands and intra-reader band counts resulted in similar precision indices with little systematic bias. However, inter-reader growth band count plots showed possible biases in counts from sectioned vertebrae and sectioned dorsal-fin spines. Sectioned vertebrae and whole and sectioned dorsal-fin spines produced similar growth band counts, whereas whole vertebrae produced significantly lower counts. The similar readability, precision indices, growth band counts and apparent absence of biases between counts for a single reader would indicate that sectioned vertebrae and whole and sectioned dorsal-fin spines are both potentially useful and acceptable methods for band counting. However, inter-reader comparisons are necessary to avoid acceptance of biased estimations, resulting in over- or under-estimations of age. Validation for all age classes is essential to determining accurate age estimations for this and other species.

scholarly journals Beyond Post-release Mortality: Inferences on Recovery Periods and Natural Mortality From Electronic Tagging Data for Discarded Lamnid Sharks

2021 ◽  
Vol 8 ◽  
Author(s):  
Heather D. Bowlby ◽  
Hugues P. Benoît ◽  
Warren Joyce ◽  
James Sulikowski ◽  
Rui Coelho ◽  
...  
Keyword(s):  
Survival Data ◽  
Recovery Period ◽  
Age Determination ◽  
Shark Species ◽  
Natural Mortality ◽  
The North ◽  
Covariate Effects ◽  
Shortfin Mako ◽  
Electronic Tagging ◽  
Key Parameter

Accurately characterizing the biology of a pelagic shark species is critical when assessing its status and resilience to fishing pressure. Natural mortality (M) is well known to be a key parameter determining productivity and resilience, but also one for which estimates are most uncertain. While M can be inferred from life history, validated direct estimates are extremely rare for sharks. Porbeagle (Lamna nasus) and shortfin mako (Isurus oxyrinchus) are presently overfished in the North Atlantic, but there are no directed fisheries and successful live release of bycatch is believed to have increased. Understanding M, post-release mortality (PRM), and variables that affect mortality are necessary for management and effective bycatch mitigation. From 177 deployments of archival satellite tags, we inferred mortality events, characterized physiological recovery periods following release, and applied survival mixture models to assess M and PRM. We also evaluated covariate effects on the duration of any recovery period and PRM to inform mitigation. Although large sample sizes involving extended monitoring periods (>90 days) would be optimal to directly estimate M from survival data, it was possible to constrain estimates and infer probable values for both species. Furthermore, the consistency of M estimates with values derived from longevity information suggests that age determination is relatively accurate for these species. Regarding bycatch mitigation, our analyses suggest that juvenile porbeagle are more susceptible to harm during capture and handling, that keeping lamnid sharks in the water during release is optimal, and that circle hooks are associated with longer recovery periods for shortfin mako.

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.

Application of bomb radiocarbon chronologies to shortfin mako (Isurus oxyrinchus) age validation

2006 ◽  
Vol 77 (3-4) ◽  
pp. 355-366 ◽  
Author(s):  
Daniele Ardizzone ◽  
Gregor M. Cailliet ◽  
Lisa J. Natanson ◽  
Allen H. Andrews ◽  
Lisa A. Kerr ◽  
...  
Keyword(s):  
Age Validation ◽  
Isurus Oxyrinchus ◽  
Shortfin Mako ◽  
Bomb Radiocarbon

Direct determination of age in shrimps, crabs, and lobsters

2012 ◽  
Vol 69 (11) ◽  
pp. 1728-1733 ◽  
Author(s):  
Raouf Kilada ◽  
Bernard Sainte-Marie ◽  
Rémy Rochette ◽  
Neill Davis ◽  
Caroline Vanier ◽  
...  
Keyword(s):  
Age Determination ◽  
Direct Determination ◽  
Growth Curves ◽  
Accurate Method ◽  
Gastric Mill ◽  
Growth Band ◽  
Growth Bands ◽  
Chemical Tags ◽  
Age Structured ◽  
Multiple Species

The detection and measurement of annual growth bands preserved in calcified structures underlies the assessment and management of exploited fish populations around the world. However, the estimation of growth, mortality, and other age-structured processes in crustaceans has been severely limited by the apparent absence of permanent growth structures. Here, we report the detection of growth bands in calcified regions of the eyestalk or gastric mill in shrimps, crabs, and lobsters. Comparison of growth band counts with reliable, independent estimates of age strongly suggests that the bands form annually, thus providing a direct and accurate method of age determination in all of the species examined. Chemical tags in the lobster cuticle were retained through one or two molts that occurred over the duration of an experiment, as apparently was the mesocardiac ossicle containing the growth bands in the gastric mill. Growth bands are not the previously documented lamellae of the endocuticle, and their formation was not associated with molting. Sex-specific growth curves were readily developed from growth band examination in multiple species, suggesting that routine measurement of growth and mortality in decapod crustaceans may now be possible.

Age determination and growth estimation from otolith micro-increments and fin spine sections of blue marlin (Makaira nigricans) in the western North Pacific

2015 ◽  
Vol 66 (12) ◽  
pp. 1116 ◽  
Author(s):  
Tamaki Shimose ◽  
Kotaro Yokawa ◽  
Katsunori Tachihara
Keyword(s):  
Growth Parameters ◽  
Age Determination ◽  
Fork Length ◽  
Annual Growth ◽  
Growth Band ◽  
Blue Marlin ◽  
Makaira Nigricans ◽  
Growth Bands ◽  
Growth Estimation ◽  
Fin Spines

Age determination and growth estimation of blue marlin (Makaira nigricans) were performed by combining method of otolith micro-increment counts of 27 young (17–185-cm lower jaw–fork length, LJFL) and sectioned dorsal fin spines of 571 adult individuals (155–352cm). Otolith micro-increments were counted with ages of 26–338 days old. The estimated mean length (185cm) at Year 1 and growth rate were used to predict the position of the first annual growth band in sectioned fin spines. Distinct growth bands were formed in fin spines annually between September and October. Indistinct growth bands were considered false-annual growth bands. The observed and back-calculated LJFLs at each age were highly variable for both sexes. Von Bertalanffy growth parameters were estimated using mean back-calculated LJFL data as: L∞=295cm, k=0.23, t0=–3.31 years for females and 212cm, 0.29, –4.49 years for males. Females grew to >200cm in 2 years and to >250cm in 5 years on average, whereas the growth of males slowed appreciably after they reached the age of 1 year. This is the first study of blue marlin growth for entire life stages.

Evaluation of staining techniques for the observation of growth bands in tropical elasmobranch vertebrae

2020 ◽  
Vol 84 (4) ◽  
pp. 343-354
Author(s):  
José G. Pérez-Rojas ◽  
Katherine Torres-Palacios ◽  
Amalia Uribe ◽  
Andrés F. Navia ◽  
Paola A. Mejía-Falla
Keyword(s):  
Age And Growth ◽  
Tropical Species ◽  
Shark Species ◽  
Growth Band ◽  
Sphyrna Lewini ◽  
Specific Protocol ◽  
Growth Bands ◽  
Staining Techniques ◽  
Hard Structures ◽  
Species Specific

The aim of this study was to assess the suitability of different vertebrae staining techniques for the visualization and counting of growth bands in tropical species of batoids (Narcine leoparda, Urotrygon aspidura, Hypanus longus, Potamotrygon magdalenae) and sharks (Alopias pelagicus, Carcharhinus falciformis, Sphyrna lewini, Sphyrna corona and Mustelus lunulatus). Different cutting thicknesses and staining protocols were tested, analysing the precision and bias of each combination to identify the most accurate technique for estimating age. Vertebral sections of 0.4 mm were more suitable for batoids, except for Narcine leoparda; for this species and for all the shark species assessed, sections of 0.5 mm are recommended. Different combinations of stain and exposure time were required to achieve the best visualizations of vertebral growth band pair for the shark and ray species. Intraspecific variation occurred among vertebrae size of batoids. Our results confirm the importance of defining a suitable species-specific protocol for sectioning and staining hard structures before carrying out an age and growth study to improve the reliability of the age estimates.

Long-term migration patterns and bisexual philopatry in a benthic shark species

2017 ◽  
Vol 68 (8) ◽  
pp. 1414 ◽  
Author(s):  
Nathan Charles Bass ◽  
Johann Mourier ◽  
Nathan A. Knott ◽  
Joanna Day ◽  
Tristan Guttridge ◽  
...  
Keyword(s):  
Management Strategies ◽  
Movement Patterns ◽  
Conclusive Evidence ◽  
Migration Route ◽  
Shark Species ◽  
Apex Predators ◽  
Arrival Times ◽  
And Bisexual ◽  
Australian Coastline ◽  
Port Jackson

Knowledge of the broad-scale movement patterns of sharks is essential to developing effective management strategies. Currently there is a large bias in studies focusing on species that are either large apex predators or found in tropical to subtropical regions. There is limited knowledge of the movements and migrations of benthic and temperate shark species. The present study used passive acoustic telemetry to investigate the movement patterns of a benthic shark species, the Port Jackson shark (Heterodontus portusjacksoni). Individuals were tagged with acoustic transmitters between 2012 and 2014 and their movements were monitored within Jervis Bay and along the east Australian coastline for up to 4 years. Male and female Port Jackson sharks demonstrated high levels of philopatry to both Jervis Bay and their tagging location across multiple years. Although males and females did not differ in their arrival times, females departed from Jervis Bay later than males. Approximately half the tagged individuals migrated in a southward direction, with individuals being detected at Narooma, Bass Strait and Cape Barron Island. This study provides conclusive evidence of bisexual philopatry in a benthic temperate shark species, confirming previous hypotheses, and presents the most detailed migration route for Port Jackson sharks to date.

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