ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Unknown

Vertebral bomb radiocarbon suggests extreme longevity in white sharks (2014)

Hamady, Li Ling ; Natanson, Lisa J. ; Skomal, Gregory B. ; [et al.]

Public Library of Science

add to mindlist on the mindlist

Details

Publication Date: 2022-05-25

Description: This article is distributed free of all copyright. The definitive version was published in PLoS One 9 (2014): e84006, doi:10.1371/journal.pone.0084006.

Description: Conservation and management efforts for white sharks (Carcharodon carcharias) remain hampered by a lack of basic demographic information including age and growth rates. Sharks are typically aged by counting growth bands sequentially deposited in their vertebrae, but the assumption of annual deposition of these band pairs requires testing. We compared radiocarbon (Δ14C) values in vertebrae from four female and four male white sharks from the northwestern Atlantic Ocean (NWA) with reference chronologies documenting the marine uptake of 14C produced by atmospheric testing of thermonuclear devices to generate the first radiocarbon age estimates for adult white sharks. Age estimates were up to 40 years old for the largest female (fork length [FL]: 526 cm) and 73 years old for the largest male (FL: 493 cm). Our results dramatically extend the maximum age and longevity of white sharks compared to earlier studies, hint at possible sexual dimorphism in growth rates, and raise concerns that white shark populations are considerably more sensitive to human-induced mortality than previously thought.

Description: This study was funded by the National Science Foundation (OCE 0825148 was awarded to SRT) and LLH was supported by the National Science Foundation Graduate Research Fellowship Program.

Repository Name: Woods Hole Open Access Server

Type: Article

Format: application/pdf

Format: application/msword

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Fulltext

2

Unknown

Age, movements, and feeding ecology of northwest Atlantic white sharks estimated from ecogeochemical profiles in vertebrae (2014)

Hamady, Li Ling

Massachusetts Institute of Technology and Woods Hole Oceanographic Institution

add to mindlist on the mindlist

Details

Publication Date: 2022-05-25

Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2014

Description: White sharks (Carcharodon carcharias) are highly migratory, ecologically important, vulnerable, and understudied marine predators. Ecogeochemistry, which takes advantage of natural variations in chemical signatures recorded in body tissues, can help determine lifetime movement, age, and ontogenetic diet history in difficult to study species. Shark vertebrae are constructed of distinct layers of tissue laid down sequentially over an individual’s lifetime and may preserve a chemical record of environmental exposure. In this thesis, I investigate the ecology of the understudied northwest Atlantic (NWA) white shark population by applying several ecogeochemistry techniques to their vertebrae. I generate the first radiocarbon (Δ14C) age estimates for adult white sharks, dramatically extending the maximum age and longevity compared to earlier age studies. Δ14C results also verify a lack of reworking of vertebral material and hint at possible sexual dimorphism in growth rates. Using amino acid and bulk stable isotope analyses, I show that individual sharks have marked variation in feeding and movement, and that pinnipeds do not constitute a large portion of their diet. Finally, I explore the utility of elemental chemistry to retrospectively infer movement. This work provides an important informational baseline for future NWA white shark ecological studies and conservation and management efforts.

Description: I received support from a National Science Foundation Graduate Research Fellowship and the WHOI Academic Programs Office. The research in this thesis was funded by a National Science Foundation Grant (OCE 0825148) to S. Thorrold. Additional support came from an ITCE (Inter-university Training for Continental-scale Ecology) Research in Residence Fellowship.

Keywords: Environmental chemistry

Repository Name: Woods Hole Open Access Server

Type: Thesis

Format: application/pdf

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Fulltext

3

Unknown

A review of ecogeochemistry approaches to estimating movements of marine animals (2014)

McMahon, Kelton W. ; Hamady, Li Ling ; Thorrold, Simon R.

Association for the Sciences of Limnology and Oceanography

add to mindlist on the mindlist

Details

Publication Date: 2022-05-25

Description: Author Posting. © Association for the Sciences of Limnology and Oceanography, 2013. This article is posted here by permission of Association for the Sciences of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 58 (2013): 697-714, doi:10.4319/lo.2013.58.2.0697.

Description: Ecogeochemistry—the application of geochemical techniques to fundamental questions in population and community ecology—has been used in animal migration studies in terrestrial environments for several decades; however, the approach has received far less attention in marine systems. This review includes comprehensive meta-analyses of organic zooplankton δ13C and δ15N values at the base of the food web, dissolved inorganic carbon δ13C values, and seawater δ18O values to create, for the first time, robust isoscapes for the Atlantic Ocean. These isoscapes present far greater geographic variability in multiple geochemical tracers than was previously thought, thus forming the foundation for reconstructions of habitat use and migration patterns of marine organisms. We review several additional tracers, including trace-element-to-calcium ratios and heavy element stable isotopes, to examine anadromous migrations. We highlight the value of the ecogeochemistry approach by examining case studies on three components of connectivity: dispersal and natal homing, functional connectivity, and migratory connectivity. We also discuss recent advances in compound-specific stable carbon and nitrogen isotope analyses for tracking animal movement. A better understanding of isotopic routing and fractionation factors, particularly of individual compound classes, is necessary to realize the full potential of ecogeochemistry.

Description: We were supported by funding from the National Science Foundation (Division of Ocean Sciences–0825148 to S.R.T.), Award USA 00002 and KSA 00011 from the King Abdullah University of Science and Technology (to S.R.T.), and a National Science Foundation Graduate Research Fellowship (to L.H.).

Repository Name: Woods Hole Open Access Server

Type: Article

Format: application/pdf

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Fulltext

4

Unknown

Validated age and growth estimates for Carcharhinus obscurus in the northwestern Atlantic Ocean, with pre- and post management growth comparisons (2014)

Natanson, Lisa J. ; Gervelis, Brian J. ; Winton, Megan V. ; [et al.]

Springer

add to mindlist on the mindlist

Details

Publication Date: 2022-05-26

Description: This paper is not subject to U.S. copyright. The definitive version was published in Environmental Biology of Fishes 97 (2014): 881-896, doi:10.1007/s10641-013-0189-4.

Description: Age and growth estimates for the dusky shark, Carcharhinus obscurus, were derived from vertebral centra collected in the northwestern Atlantic Ocean. Sample collection spanned the years prior to and following the implementation of management measures (1963–2010). Growth was compared pre- and post- population depletion and pre- and post- management to investigate the possibility of density-mediated shifts in age and growth parameters over time. There was no evidence of difference between periods for either sex. Additionally, bomb radiocarbon dating was used to determine the periodicity of band pair formation. Results support the traditional interpretation of annual band pairs up to approximately 11 years of age. After this time, vertebral counts considerably underestimate true age. Maximum validated ages were estimated to be between 38 and 42 years of age (an increase of 15 to 19 years over the band count estimates), confirming longevity to at least 42 years of age. Growth curves estimated using only validated data were compared to those generated using band pair counts. Logistic growth parameters derived from validated vertebral length-at-age data were L ∞ = 261.5 cm FL, L o = 85.5 cm, t o = 4.89 year and g = 0.15 year−1 for the sexes combined. Revised estimates of age at maturity were 17.4 years for males and 17.6 years for females.

Keywords: Dusky shark ; Age and growth ; Elasmobranch ; Vertebrae ; Bomb radiocarbon ; Validation

Repository Name: Woods Hole Open Access Server

Type: Article

Format: application/pdf

Permalink