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Bianchi SJ, Roman JM, Lucifora LO, Barbini SA. Life-history traits of an exploited skate: The short-tail yellownose skate Zearaja brevicaudata (Chondrichthyes: Rajiformes). JOURNAL OF FISH BIOLOGY 2024; 104:1875-1887. [PMID: 38501373 DOI: 10.1111/jfb.15712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/16/2024] [Accepted: 02/17/2024] [Indexed: 03/20/2024]
Abstract
The short-tail yellownose skate, Zearaja brevicaudata, occurs off southern Brazil and along the Argentine continental shelf, including waters surrounding the Islas Malvinas and the upper slope, and is very frequently caught by trawl fisheries throughout its range. The age, growth, and maturity of Z. brevicaudata were investigated using 204 individuals collected by commercial fishing vessels from northern Argentina, between March 2016 and September 2019. Age was determined on a sample comprising vertebrae from 151 individuals, 60 males, ranging in size from 391 to 956 mm total length (TL), and 91 females, ranging in size from 324 to 1060 mm TL. Maximum ages determined for males and females were 22 and 29 years, respectively. A Bayesian framework was employed with a set of three candidate models to estimate growth parameters (von Bertalanffy, Gompertz, and Logistic). The von Bertalanffy model had the best fit, and the sexes showed undistinguishable growth parameters. For sexes combined, derived growth mean parameters (± S.D.) were L∞ = 1081 mm ± 64.34 mm, k = 0.09 ± 0.01 years-1, and L0 = 248 mm ± 23.52 mm. The age at maturity was estimated at 13.15 and 14.66 years for males and females, respectively.
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Affiliation(s)
- Santiago J Bianchi
- Biología de Peces, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata (UNMdP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata, Buenos Aires, Argentina
| | - Jorge M Roman
- Biología de Peces, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata (UNMdP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata, Buenos Aires, Argentina
| | - Luis O Lucifora
- Instituto Nacional de Limnología (INALI), Universidad Nacional del Litoral (UNL), CONICET, Ciudad de Santa Fe, Santa Fe, Argentina
| | - Santiago A Barbini
- Biología de Peces, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata (UNMdP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata, Buenos Aires, Argentina
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2
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Swenson JD, Brooks EN, Kacev D, Boyd C, Kinney MJ, Marcy‐Quay B, Sévêque A, Feldheim KA, Komoroske LM. Accounting for unobserved population dynamics and aging error in close-kin mark-recapture assessments. Ecol Evol 2024; 14:e10854. [PMID: 38327683 PMCID: PMC10847890 DOI: 10.1002/ece3.10854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 01/01/2024] [Accepted: 01/05/2024] [Indexed: 02/09/2024] Open
Abstract
Obtaining robust estimates of population abundance is a central challenge hindering the conservation and management of many threatened and exploited species. Close-kin mark-recapture (CKMR) is a genetics-based approach that has strong potential to improve the monitoring of data-limited species by enabling estimates of abundance, survival, and other parameters for populations that are challenging to assess. However, CKMR models have received limited sensitivity testing under realistic population dynamics and sampling scenarios, impeding the application of the method in population monitoring programs and stock assessments. Here, we use individual-based simulation to examine how unmodeled population dynamics and aging uncertainty affect the accuracy and precision of CKMR parameter estimates under different sampling strategies. We then present adapted models that correct the biases that arise from model misspecification. Our results demonstrate that a simple base-case CKMR model produces robust estimates of population abundance with stable populations that breed annually; however, if a population trend or non-annual breeding dynamics are present, or if year-specific estimates of abundance are desired, a more complex CKMR model must be constructed. In addition, we show that CKMR can generate reliable abundance estimates for adults from a variety of sampling strategies, including juvenile-focused sampling where adults are never directly observed (and aging error is minimal). Finally, we apply a CKMR model that has been adapted for population growth and intermittent breeding to two decades of genetic data from juvenile lemon sharks (Negaprion brevirostris) in Bimini, Bahamas, to demonstrate how application of CKMR to samples drawn solely from juveniles can contribute to monitoring efforts for highly mobile populations. Overall, this study expands our understanding of the biological factors and sampling decisions that cause bias in CKMR models, identifies key areas for future inquiry, and provides recommendations that can aid biologists in planning and implementing an effective CKMR study, particularly for long-lived data-limited species.
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Affiliation(s)
- John D. Swenson
- Department of Environmental ConservationThe University of Massachusetts AmherstAmherstMassachusettsUSA
| | - Elizabeth N. Brooks
- Population Dynamics Branch, Northeast Fisheries Science Center, National Marine Fisheries ServiceNational Oceanic and Atmospheric AdministrationWoods HoleMassachusettsUSA
| | - Dovi Kacev
- Marine Biology Research DivisionScripps Institution of OceanographySan DiegoCaliforniaUSA
| | - Charlotte Boyd
- International Union for Conservation of NatureNorth America OfficeWashington DCMarylandUSA
| | - Michael J. Kinney
- NOAA FisheriesPacific Island Fisheries Science CenterHonoluluHawaiiUSA
| | - Benjamin Marcy‐Quay
- Rubenstein Ecosystem Science LaboratoryUniversity of VermontBurlingtonVermontUSA
| | - Anthony Sévêque
- Department of Wildlife, Fisheries and Aquaculture, Forest and Wildlife Research CenterMississippi State UniversityMississippi StateMississippiUSA
| | - Kevin A. Feldheim
- Pritzker Laboratory for Molecular Systematics and EvolutionThe Field MuseumChicagoIllinoisUSA
| | - Lisa M. Komoroske
- Department of Environmental ConservationThe University of Massachusetts AmherstAmherstMassachusettsUSA
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3
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Schieber JJ, Fahy DP, Carlson JK, Kerstetter DW. Age, growth and maturity of the yellow stingray (Urobatis jamaicensis), a biannually reproductive tropical batoid. JOURNAL OF FISH BIOLOGY 2023; 102:1281-1295. [PMID: 36895092 DOI: 10.1111/jfb.15374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/08/2023] [Indexed: 06/09/2023]
Abstract
Urobatis jamaicensis is a coastal batoid species affected by habitat loss and small-scale exploitation from fisheries and the aquarium trade, yet the life-history information available is limited. This is the first study to assess the vertebral centra from 195 stingrays to estimate age and growth patterns, and compare them with the biannual reproductive pattern previously reported for this species. Age-at-size data were compared using five different growth models and found a two-parameter von Bertalanffy growth function (VBGF), the Gompertz model and a modified VBGF fit best for males, females and sexes combined, respectively. Maturity was achieved before 1 year. However, growth did not cease with the onset of maturity, but instead slowed down. Results from marginal increment analysis and edge analysis indicated a nonannual somatic growth pattern with influences from the biannual reproduction cycle where peaks in resource allocation may be focused on ovulation rather than growth during March when larger brood sizes are present, while resources may be allocated more towards growth during August and September when brood sizes are generally smaller. These results may be used as a proxy for species with similar reproductive patterns or for those that lack annual or seasonal growth patterns.
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Affiliation(s)
- Jessica J Schieber
- Halmos College of Arts and Sciences, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, Florida, 33004, USA
| | - Daniel P Fahy
- Halmos College of Arts and Sciences, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, Florida, 33004, USA
| | - John K Carlson
- National Oceanic and Atmospheric Association, National Marine Fisheries Service, 3500 Delwood Beach Road, Panama City, Florida, 32408, USA
| | - David W Kerstetter
- Halmos College of Arts and Sciences, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, Florida, 33004, USA
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4
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Bowlby HD, Hammerschlag N, Irion DT, Gennari E. How continuing mortality affects recovery potential for prohibited sharks: The case of white sharks in South Africa. FRONTIERS IN CONSERVATION SCIENCE 2022. [DOI: 10.3389/fcosc.2022.988693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
It can be difficult to determine whether a prohibition to exploitation ensures effective conservation or recovery for species that remain exposed to fishing effort and other sources of mortality throughout their range. Here we used simulation modeling of four life history scenarios (different productivity and population size) to contextualize potential population response to multiple levels of mortality, using white sharks (Carcharodon carcharias) in South Africa as a case study. The species has been protected since 1991, yet substantial uncertainty about population dynamics persists and recent declines at two aggregation sites have renewed conservation concern. All scenarios indicated that annual removals in the 10s of individuals would substantially limit the potential for and magnitude of any abundance increase following prohibition. Because average known removals from the KwaZulu-Natal Sharks Board’s Bather Protection Program have typically remained higher than these thresholds, they likely eliminated much of the conservation benefit derived from prohibition. The only life history scenario to achieve appreciable increase when simulated removals were similar to published averages assumed maturation occurred at a much younger age than currently understood. Our results demonstrate why general application of life history-based simulations can provide a useful mechanism to evaluate the biological plausibility of life history information and abundance trends, and to explore the scope for population response to recovery actions. For South Africa, our results suggest that even known levels of white shark removals, which likely underestimate total removals within their range, may be sufficient to drive abundance decline and new mitigation measures may be required to ensure population recovery.
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5
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Kurniawan W, Tibbetts IR, Oktaviyani S, Dudgeon CL, Bennett MB. Age and growth of the tropical oviparous shark, Chiloscyllium punctatum in Indonesian waters. JOURNAL OF FISH BIOLOGY 2021; 99:921-930. [PMID: 33977550 DOI: 10.1111/jfb.14778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
The brown-banded bamboo shark, Chiloscyllium punctatum, is the most common shark caught in coastal commercial fisheries throughout Southeast Asia, yet there is a lack of the life-history information necessary for reliable stock assessments. The authors estimated growth rates and age at maturity using analysis of growth bands in vertebral centra. They trialled four different techniques to enhance the visibility and improve identification of the putative annual growth bands necessary for age estimation. The authors found that the burn method on whole vertebral centra provided the most readable and consistent results for age analysis. The logistic model was chosen as the best-fit growth model for age estimation of 330 individual C. punctatum from Indonesia. Several age verification methods, including marginal increment ratio and length-frequency analysis, were performed with the support of age validation through the use of calcein-labelled vertebrae from two sharks maintained in captivity. This study found that C. punctatum from Indonesian waters is a fast-growing species that can grow up to 18 cm year-1 , reach an estimated maximum total length of 1 m, mature at c. 6.5 years and live for up to 14 years.
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Affiliation(s)
- Wanwan Kurniawan
- Research Centre for Oceanography, Indonesian Institute of Sciences (LIPI), Jakarta, Indonesia
| | - Ian R Tibbetts
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Selvia Oktaviyani
- Research Centre for Oceanography, Indonesian Institute of Sciences (LIPI), Jakarta, Indonesia
| | - Christine L Dudgeon
- School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Michael B Bennett
- School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia
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6
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Pacoureau N, Rigby CL, Kyne PM, Sherley RB, Winker H, Carlson JK, Fordham SV, Barreto R, Fernando D, Francis MP, Jabado RW, Herman KB, Liu KM, Marshall AD, Pollom RA, Romanov EV, Simpfendorfer CA, Yin JS, Kindsvater HK, Dulvy NK. Half a century of global decline in oceanic sharks and rays. Nature 2021; 589:567-571. [PMID: 33505035 DOI: 10.1038/s41586-020-03173-9] [Citation(s) in RCA: 163] [Impact Index Per Article: 54.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/27/2020] [Indexed: 11/09/2022]
Abstract
Overfishing is the primary cause of marine defaunation, yet declines in and increasing extinction risks of individual species are difficult to measure, particularly for the largest predators found in the high seas1-3. Here we calculate two well-established indicators to track progress towards Aichi Biodiversity Targets and Sustainable Development Goals4,5: the Living Planet Index (a measure of changes in abundance aggregated from 57 abundance time-series datasets for 18 oceanic shark and ray species) and the Red List Index (a measure of change in extinction risk calculated for all 31 oceanic species of sharks and rays). We find that, since 1970, the global abundance of oceanic sharks and rays has declined by 71% owing to an 18-fold increase in relative fishing pressure. This depletion has increased the global extinction risk to the point at which three-quarters of the species comprising this functionally important assemblage are threatened with extinction. Strict prohibitions and precautionary science-based catch limits are urgently needed to avert population collapse6,7, avoid the disruption of ecological functions and promote species recovery8,9.
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Affiliation(s)
- Nathan Pacoureau
- Department of Biological Sciences, Earth to Ocean Research Group, Simon Fraser University, Burnaby, British Columbia, Canada.
| | - Cassandra L Rigby
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Peter M Kyne
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Richard B Sherley
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, UK.
| | - Henning Winker
- Joint Research Centre (JRC), European Commission, Ispra, Italy.,Department of Environment, Forestry and Fisheries, Cape Town, South Africa
| | - John K Carlson
- NOAA National Marine Fisheries Service, Southeast Fisheries Science Center, Panama City Laboratory, Panama City, FL, USA
| | - Sonja V Fordham
- Shark Advocates International, The Ocean Foundation, Washington, DC, USA
| | - Rodrigo Barreto
- Centro Nacional de Pesquisa e Conservação da Biodiversidade Marinha do Sudeste e Sul do Brasil (CEPSUL), Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio), Itajaí, Brazil
| | | | - Malcolm P Francis
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
| | | | | | - Kwang-Ming Liu
- Institute of Marine Affairs and Resource Management, George Chen Shark Research Center, National Taiwan Ocean University, Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
| | | | - Riley A Pollom
- Department of Biological Sciences, Earth to Ocean Research Group, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | - Colin A Simpfendorfer
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Jamie S Yin
- Department of Biological Sciences, Earth to Ocean Research Group, Simon Fraser University, Burnaby, British Columbia, Canada.,Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA
| | - Holly K Kindsvater
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Nicholas K Dulvy
- Department of Biological Sciences, Earth to Ocean Research Group, Simon Fraser University, Burnaby, British Columbia, Canada
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7
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Rolim FA, Siders ZA, Caltabellotta FP, Rotundo MM, Vaske-Júnior T. Growth and derived life-history characteristics of the Brazilian electric ray Narcine brasiliensis. JOURNAL OF FISH BIOLOGY 2020; 97:396-408. [PMID: 32402101 DOI: 10.1111/jfb.14378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
The majority of batoids are listed as Threatened (20.4%) or Data Deficient (41%) by the IUCN Red List. A key challenge to assessing Data-Deficient species is obtaining estimates of key life-history characteristics. Here, a Bayesian approach was used to estimate derived life-history characteristics from a growth model applied to the Data-Deficient Brazilian electric ray Narcine brasiliensis. The age of 170 specimens (107 females, 63 males) was estimated from vertebral centra, and total length, disc width, total weight and birth size were used in a joint estimation of sex-specific length-weight models and two-dimensional von Bertalanffy growth models. Estimates of age at length zero, age at maturity, longevity and mortality at age were derived simultaneously. The Bayesian joint modelling approach was robust to small sample sizes by adding a likelihood to constrain L0 and sharing parameters, such as Brody growth coefficient between length measurements. The median growth parameter estimates were a shared L0 = 38.8 mm, female L∞ = 515 mm, 𝑘 = 0.125 and male L∞ = 387 mm, 𝑘 = 0.194. Age at maturity was estimated to be 7.40-7.49 years for females and 4.45-4.47 years for males, whereas longevity was 22.5-22.6 years for females and 14.2 years for males depending on length measurement. Age-1 natural mortality was estimated to be 0.199-0.207 for females and 0.211-0.213 for males. The derived life-history characteristics indicate N. brasiliensis is earlier maturing, but slower growing relative to other Torpediniformes. These characteristics along with the species' endemism to southern Brazil and high by-catch rates indicate that one of the IUCN Red List threatened categories may be more appropriate for the currently Data-Deficient status. The Bayesian approach used for N. brasiliensis can prove useful for utilizing limited age-growth data in other Data-Deficient batoid species to inform necessary life characteristics for conservation and management.
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Affiliation(s)
- Fernanda A Rolim
- Elasmobranch Research Laboratory, Institute of Bioscience, Sao Paulo State University (UNESP), São Vicente, Brazil
| | - Zachary A Siders
- UF/IFAS SFRC Fisheries and Aquatic Sciences Program, University of Florida, Gainesville, Florida, USA
| | - Fabio P Caltabellotta
- UF/IFAS SFRC Fisheries and Aquatic Sciences Program, University of Florida, Gainesville, Florida, USA
- Coastal Oregon Marine Experiment Station, Oregon State University, Newport, Oregon, USA
| | - Matheus M Rotundo
- Zoological Collection, University Santa Cecília (UNISANTA), Santos, Brazil
| | - Teodoro Vaske-Júnior
- Institute of Bioscience, Sao Paulo State University (UNESP), São Vicente, Brazil
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8
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Bowlby HD, Gibson AJF. Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias). Ecol Evol 2020; 10:4990-5000. [PMID: 32551076 PMCID: PMC7297763 DOI: 10.1002/ece3.6252] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/12/2020] [Accepted: 03/16/2020] [Indexed: 11/05/2022] Open
Abstract
To effectively protect at-risk sharks, resource managers and conservation practitioners must have a good understanding of how fisheries removals contribute to changes in abundance and how regulatory restrictions may impact a population trajectory. This means they need to know the number of animals being removed from a population and whether a given number of removals will lead to population increases or declines. For white shark (Carcharodon carcharias), theoretical quantities like the intrinsic rate of population increase or rebound potential (ability to increase in size following decline) are difficult to conceptualize in terms of real-world abundance changes, which limits our ability to answer practical management questions. To address this shortfall, we designed a simulation model to evaluate how our understanding of longevity and life history variability of white shark affects our understanding of population trends in the Northwest Atlantic. Then, we quantified the magnitude of removals that could have caused historical population declines, compared these to biologically based reference points, and explored the removal scenarios which would result in population increase. Our results suggest that removals on the order of 100s of juveniles per year could have resulted in population-level declines in excess of 60% during the 1970s and 1980s. Conservation actions implemented since the 1990s would have needed to be nearly 100% effective at preventing fishing mortality in order for the population to double in abundance over the last 30 years. Total removals from all fleets needed to be exceptionally small to keep them below biological reference points for white shark in the Northwest Atlantic. The population's inherent vulnerability to fishing pressure reaffirms the need for restrictive national and international conservation measures, even under a situation of abundance increase.
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Affiliation(s)
- Heather D. Bowlby
- Population Ecology DivisionScience Branch, Fisheries and Oceans CanadaDartmouthNSCanada
| | - A. Jamie F. Gibson
- Population Ecology DivisionScience Branch, Fisheries and Oceans CanadaDartmouthNSCanada
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9
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Population productivity of shovelnose rays: Inferring the potential for recovery. PLoS One 2019; 14:e0225183. [PMID: 31751369 PMCID: PMC6872150 DOI: 10.1371/journal.pone.0225183] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 10/30/2019] [Indexed: 11/22/2022] Open
Abstract
There is recent evidence of widespread declines of shovelnose ray populations (Order Rhinopristiformes) in heavily fished regions. These declines, which are likely driven by high demand for their fins in Asian markets, raises concern about their risk of over-exploitation and extinction. Using life-history theory and incorporating uncertainty into a modified Euler-Lotka model, the maximum intrinsic rates of population increase (rmax) were estimated for nine species from four families of Rhinopristiformes, using four different natural mortality estimators. Estimates of mean rmax, across the different natural mortality methods, varied from 0.03 to 0.59 year-1 among the nine species, but generally increased with increasing maximum size. Comparing these estimates to rmax values for other species of chondrichthyans, the species Rhynchobatus australiae, Glaucostegus typus, and Glaucostegus cemiculus were relatively productive, while most species from Rhinobatidae and Trygonorrhinidae had relatively low rmax values. If the demand for their high-value products can be addressed then population recovery for some species is likely possible, but will vary depending on the species.
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10
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Francis MP, Ó Maolagáin C. Growth-band counts from elephantfish Callorhinchus milii fin spines do not correspond with independently estimated ages. JOURNAL OF FISH BIOLOGY 2019; 95:743-752. [PMID: 31125124 DOI: 10.1111/jfb.14060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
Fin spines from elephantfish Callorhinchus milii were sectioned and viewed with transmitted white light under a compound microscope. The sections displayed growth bands but their interpretation and significance were unclear. Three different methods were used for counting growth bands. The results were compared with reference growth curves based on length-at-age estimates for six juvenile year classes derived from length-frequency distributions, and tagging data that showed longevity is at least 20 years. None of the three ageing methods showed good correspondence with the reference curves and all methods departed markedly from the reference curves at ages above 2 years old. Therefore, growth bands present in C. milii spines are not useful for ageing, at least with the three methods tested here. Spine bands may not represent age marks, but instead may be layers of material deposited irregularly to strengthen the spine.
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Affiliation(s)
- Malcolm P Francis
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
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11
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Ketz AC, Johnson TL, Hooten MB, Hobbs NT. A hierarchical Bayesian approach for handling missing classification data. Ecol Evol 2019; 9:3130-3140. [PMID: 30962886 PMCID: PMC6434567 DOI: 10.1002/ece3.4927] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 11/21/2018] [Accepted: 01/02/2019] [Indexed: 11/29/2022] Open
Abstract
Ecologists use classifications of individuals in categories to understand composition of populations and communities. These categories might be defined by demographics, functional traits, or species. Assignment of categories is often imperfect, but frequently treated as observations without error. When individuals are observed but not classified, these "partial" observations must be modified to include the missing data mechanism to avoid spurious inference.We developed two hierarchical Bayesian models to overcome the assumption of perfect assignment to mutually exclusive categories in the multinomial distribution of categorical counts, when classifications are missing. These models incorporate auxiliary information to adjust the posterior distributions of the proportions of membership in categories. In one model, we use an empirical Bayes approach, where a subset of data from one year serves as a prior for the missing data the next. In the other approach, we use a small random sample of data within a year to inform the distribution of the missing data.We performed a simulation to show the bias that occurs when partial observations were ignored and demonstrated the altered inference for the estimation of demographic ratios. We applied our models to demographic classifications of elk (Cervus elaphus nelsoni) to demonstrate improved inference for the proportions of sex and stage classes.We developed multiple modeling approaches using a generalizable nested multinomial structure to account for partially observed data that were missing not at random for classification counts. Accounting for classification uncertainty is important to accurately understand the composition of populations and communities in ecological studies.
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Affiliation(s)
- Alison C. Ketz
- Natural Resource Ecology LabDepartment of Ecosystem Science and Sustainability, and Graduate Degree Program in EcologyColorado State UniversityFort CollinsColorado
| | | | - Mevin B. Hooten
- U.S. Geological SurveyColorado Cooperative Fish and Wildlife Research UnitColorado State UniversityFort CollinsColorado
- Department of Fish, Wildlife and Conservation BiologyColorado State UniversityFort CollinsColorado
- Department of StatisticsColorado State UniversityFort CollinsColorado
| | - N. Thompson Hobbs
- Natural Resource Ecology LabDepartment of Ecosystem Science and Sustainability, and Graduate Degree Program in EcologyColorado State UniversityFort CollinsColorado
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12
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Mohan JA, Miller NR, Herzka SZ, Sosa-Nishizaki O, Kohin S, Dewar H, Kinney M, Snodgrass O, Wells RJD. Elements of time and place: manganese and barium in shark vertebrae reflect age and upwelling histories. Proc Biol Sci 2018; 285:rspb.2018.1760. [PMID: 30404878 PMCID: PMC6235039 DOI: 10.1098/rspb.2018.1760] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/19/2018] [Indexed: 12/16/2022] Open
Abstract
As upper-level predators, sharks are important for maintaining marine food web structure, but populations are threatened by fishery exploitation. Sustainable management of shark populations requires improved understanding of migration patterns and population demographics, which has traditionally been sought through physical and/or electronic tagging studies. The application of natural tags such as elemental variations in mineralized band pairs of elasmobranch vertebrae cartilage could also reveal endogenous and exogenous processes experienced by sharks throughout their life histories. Here, elemental profiles were characterized in vertebrae encompassing complete life histories (birth-to-death) of shortfin mako (Isurus oxyrinchus), common thresher (Alopias vulpinus) and blue shark (Prionace glauca) of known tag and recapture locations in the eastern North Pacific Ocean. All sharks were injected with oxytetracycline at initial capture, released and subsequently recaptured, with individual liberty times ranging from 215 days to 6 years. Vertebral band pairs forming over the liberty intervals were verified by counting the number of band pairs deposited since the oxytetracycline band. Regular oscillations in vertebrae manganese (Mn) content corresponded well with the number of validated band pairs, suggesting that Mn variation could be used to age sharks. Increases in vertebrae barium concentration were correlated with times when individuals occupied areas with high coastal upwelling indices, the timing and spatial intensity of which varied from year to year. Interspecific relationships were probably influenced by behavioural differences in horizontal and vertical habitat use, feeding habits and thermoregulatory physiology. These results indicate that vertebral sclerochronology has the potential to advance our knowledge of elasmobranch life history including age and growth estimation and environmental reconstruction.
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Affiliation(s)
- John A Mohan
- Department of Marine Biology, Texas A&M University at Galveston, 1001 Texas Clipper Road, Galveston, TX 77553, USA
| | - Nathan R Miller
- Jackson School of Geosciences, The University of Texas at Austin, 2275 Speedway Stop C9000, Austin, TX 78712, USA
| | - Sharon Z Herzka
- Departamento de Oceanografía Biológica, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), 3918 Carretera Tijuana -Ensenada, Ensenada, Baja California 22860, Mexico
| | - Oscar Sosa-Nishizaki
- Departamento de Oceanografía Biológica, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), 3918 Carretera Tijuana -Ensenada, Ensenada, Baja California 22860, Mexico
| | - Suzanne Kohin
- Southwest Fisheries Science Center, National Marine Fisheries Service, 8901 La Jolla Shores Dr, La Jolla, CA 92037, USA
| | - Heidi Dewar
- Southwest Fisheries Science Center, National Marine Fisheries Service, 8901 La Jolla Shores Dr, La Jolla, CA 92037, USA
| | - Michael Kinney
- Ocean Associates, Southwest Fisheries Science Center, National Marine Fisheries Service, 8901 La Jolla Shores Dr, La Jolla, CA 92037, USA
| | - Owyn Snodgrass
- Ocean Associates, Southwest Fisheries Science Center, National Marine Fisheries Service, 8901 La Jolla Shores Dr, La Jolla, CA 92037, USA
| | - R J David Wells
- Department of Marine Biology, Texas A&M University at Galveston, 1001 Texas Clipper Road, Galveston, TX 77553, USA.,Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA
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13
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Localized zinc distribution in shark vertebrae suggests differential deposition during ontogeny and across vertebral structures. PLoS One 2018; 13:e0190927. [PMID: 29324879 PMCID: PMC5764331 DOI: 10.1371/journal.pone.0190927] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 12/24/2017] [Indexed: 01/09/2023] Open
Abstract
The development of shark vertebrae and the possible drivers of inter- and intra-specific differences in vertebral structure are poorly understood. Shark vertebrae are used to examine life-history traits related to trophic ecology, movement patterns, and the management of fisheries; a better understanding of their development would be beneficial to many fields of research that rely on these calcified structures. This study used Scanning X-ray Fluorescence Microscopy to observe zinc distribution within vertebrae of ten shark species from five different orders. Zinc was mostly localised within the intermedialis and was generally detected at levels an order of magnitude lower in the corpus calcareum. In most species, zinc concentrations were higher pre-birth mark, indicating a high rate of pre-natal zinc deposition. These results suggest there are inter-specific differences in elemental deposition within vertebrae. Since the deposition of zinc is physiologically-driven, these differences suggest that the processes of growth and deposition are potentially different in the intermedialis and corpus calcareum, and that caution should be taken when extrapolating information such as annual growth bands from one structure to the other. Together these results suggest that the high inter-specific variation in vertebral zinc deposition and associated physiologies may explain the varying effectiveness of ageing methodologies applied to elasmobranch vertebrae.
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Kacev D, Sippel TJ, Kinney MJ, Pardo SA, Mull CG. An Introduction to Modelling Abundance and Life History Parameters in Shark Populations. ADVANCES IN MARINE BIOLOGY 2017; 78:45-87. [PMID: 29056143 DOI: 10.1016/bs.amb.2017.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Elasmobranchs play critically important ecological roles throughout the world's oceans, yet in many cases, their slow life histories and interactions with fisheries makes them particularly susceptible to exploitation. Management for these species requires robust scientific input, and mathematical models are the backbone of science-based management. In this chapter, we provide an introductory overview of the use of mathematical models to estimate shark abundance. First, we discuss life history models that are used to understand the basic biology of elasmobranchs. Second, we cover population dynamics models, which are used to make inferences regarding population trend, size, and risk of extinction. Finally, we provide examples of applied models used to assess the status of elasmobranchs in the Northeast Pacific Ocean to guide management for these species. This chapter is not a comprehensive review of quantitative methods, but rather introduces various mathematical tools in fisheries management, with a focus on shark management in the Northeast Pacific Ocean.
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Affiliation(s)
- Dovi Kacev
- Ocean Associates, Inc., Arlington, VA, United States.
| | | | | | - Sebastián A Pardo
- Earth to Ocean Research Group, Simon Fraser University, Burnaby, BC, Canada
| | - Christopher G Mull
- Earth to Ocean Research Group, Simon Fraser University, Burnaby, BC, Canada
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15
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Matta ME, Tribuzio CA, Ebert DA, Goldman KJ, Gburski CM. Age and Growth of Elasmobranchs and Applications to Fisheries Management and Conservation in the Northeast Pacific Ocean. ADVANCES IN MARINE BIOLOGY 2017; 77:179-220. [PMID: 28882214 DOI: 10.1016/bs.amb.2017.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In addition to being an academic endeavour, the practical purpose of conducting age and growth studies on fishes is to provide biological data to stock assessment scientists and fisheries managers so they may better understand population demographics and manage exploitation rates. Age and size data are used to build growth models, which are a critical component of stock assessments. Though age determination of elasmobranchs in the northeast Pacific Ocean (NEP) began in the 1930s, the field has evolved substantially in recent years, allowing scientists to incorporate age data into assessments for more species than ever before. Owing to the highly diverse biology of this group of fishes, each species has its own set of challenges with regard to age determination. Age determination methods typically rely on semicalcified hard structures that form regular growth patterns; however, the structure selected and preparation method used is often species specific. New staining techniques have improved the ability to assess age and improve ageing precision for some species, and advances in microchemical methods have allowed for independent means of estimating age and validating age determination accuracy. Here we describe current age determination methods for NEP elasmobranchs. While the library of available techniques is increasing, there are still some NEP species for which reliable ageing methods have yet to be defined; we discuss these challenges and potential avenues of future research. Finally, we conclude by describing how age estimates are used in growth models and subsequently in stock assessments of selected NEP elasmobranchs.
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Affiliation(s)
- Mary E Matta
- Resource Ecology and Fisheries Management, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, United States.
| | - Cindy A Tribuzio
- Auke Bay Laboratories, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Juneau, AK, United States
| | - David A Ebert
- Pacific Shark Research Center, Moss Landing Marine Laboratories, Moss Landing, CA, United States
| | | | - Christopher M Gburski
- Resource Ecology and Fisheries Management, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, United States
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16
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Bradley D, Conklin E, Papastamatiou YP, McCauley DJ, Pollock K, Kendall BE, Gaines SD, Caselle JE. Growth and life history variability of the grey reef shark (Carcharhinus amblyrhynchos) across its range. PLoS One 2017; 12:e0172370. [PMID: 28207874 PMCID: PMC5313192 DOI: 10.1371/journal.pone.0172370] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 02/03/2017] [Indexed: 11/18/2022] Open
Abstract
For broadly distributed, often overexploited species such as elasmobranchs (sharks and rays), conservation management would benefit from understanding how life history traits change in response to local environmental and ecological factors. However, fishing obfuscates this objective by causing complex and often mixed effects on the life histories of target species. Disentangling the many drivers of life history variability requires knowledge of elasmobranch populations in the absence of fishing, which is rarely available. Here, we describe the growth, maximum size, sex ratios, size at maturity, and offer a direct estimate of survival of an unfished population of grey reef sharks (Carcharhinus amblyrhynchos) using data from an eight year tag-recapture study. We then synthesized published information on the life history of C. amblyrhynchos from across its geographic range, and for the first time, we attempted to disentangle the contribution of fishing from geographic variation in an elasmobranch species. For Palmyra's unfished C. amblyrhynchos population, the von Bertalanffy growth function (VBGF) growth coefficient k was 0.05 and asymptotic length L∞ was 163.3 cm total length (TL). Maximum size was 175.5 cm TL from a female shark, length at maturity was estimated at 116.7-123.2 cm TL for male sharks, maximum lifespan estimated from VBGF parameters was 18.1 years for both sexes combined, and annual survival was 0.74 year-1. Consistent with findings from studies on other elasmobranch species, we found significant intraspecific variability in reported life history traits of C. amblyrhynchos. However, contrary to what others have reported, we did not find consistent patterns in life history variability as a function of biogeography or fishing. Ultimately, the substantial, but not yet predictable variability in life history traits observed for C. amblyrhynchos across its geographic range suggests that regional management may be necessary to set sustainable harvest targets and to recover this and other shark species globally.
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Affiliation(s)
- Darcy Bradley
- Bren School of Environmental Science and Management, University of California Santa Barbara, Santa Barbara, California, United States of America
- * E-mail:
| | - Eric Conklin
- The Nature Conservancy, Honolulu, Hawaii, United States of America
| | - Yannis P. Papastamatiou
- Department of Biological Sciences, Florida International University, North Miami, Florida, United States of America
| | - Douglas J. McCauley
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Kydd Pollock
- The Nature Conservancy, Honolulu, Hawaii, United States of America
| | - Bruce E. Kendall
- Bren School of Environmental Science and Management, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Steven D. Gaines
- Bren School of Environmental Science and Management, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Jennifer E. Caselle
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
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17
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Dureuil M, Worm B. Estimating growth from tagging data: an application to north-east Atlantic tope shark Galeorhinus galeus. JOURNAL OF FISH BIOLOGY 2015; 87:1389-1410. [PMID: 26709213 DOI: 10.1111/jfb.12830] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/25/2015] [Indexed: 06/05/2023]
Abstract
This study addresses the inherent uncertainty when estimating growth from limited mark-recapture information. A selection procedure was developed utilizing 18 competing growth estimation methods. The optimal method for a given data set was identified by simulating the length at capture and recapture under different scenarios of measurement error and growth variability while considering the structure of observed data. This selection procedure was applied to mark-recapture data for 37 female and 16 male tope sharks Galeorhinus galeus obtained from tagging studies in the north-east Atlantic Ocean. Parameter estimates differed strongly among methods, showing the need for careful method selection. The selection approach suggested that best estimates for males and females were given by James' weighted least-squares approach with a fixed asymptote. Given an average total length (LT) at birth of 28 cm, the von Bertalanffy growth function of north-east Atlantic G. galeus would be LT = 200·85 - (200·85 - 28)e(-0·076t) for females and LT = 177·30 - (177·30 - 28)e(-0·081t) for males. The resulting age estimates were up to 11 years lower when compared with previous estimates derived from highly uncertain vertebrae readings. More generally, this procedure can help identify optimal estimation methods for a given data set and therefore aid in estimating more reliable growth parameters from mark-recapture information.
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Affiliation(s)
- M Dureuil
- Department of Biology, Dalhousie University, 1355 Oxford St., P. O. Box 15000, Halifax, NS B3H 4R2, Canada
| | - B Worm
- Department of Biology, Dalhousie University, 1355 Oxford St., P. O. Box 15000, Halifax, NS B3H 4R2, Canada
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18
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Sims DW. The biology, ecology and conservation of elasmobranchs: recent advances and new frontiers. JOURNAL OF FISH BIOLOGY 2015; 87:1265-1270. [PMID: 26709207 DOI: 10.1111/jfb.12861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- D W Sims
- Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth PL1 2PB, U.K
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, U.K
- Centre for Biological Sciences, Building 85, University of Southampton, Highfield Campus, Southampton SO17 1BJ, U.K
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