ORCID Profile
0000-0002-5530-0073
Current Organisation
CSIRO
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Publisher: Elsevier BV
Date: 12-2015
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/MF10155
Abstract: Small-scale and artisanal fisheries for sharks exist in most inshore, tropical regions of the world. Although often important in terms of food security, their low value and inherent complexity provides an imposing hurdle to sustainable management. An observer survey of a small-scale commercial gill-net fishery operating within the Great Barrier Reef World Heritage area revealed at least 38 species of elasmobranch were present in the catch. Of the total elasmobranch catch, 95% was 25 species of Carcharhiniformes from the families Carcharhinidae, Hemigaleidae and Sphyrnidae. In idual species were captured in a variety of ways by the fishery, often with strongly biased sex ratios and in a variety of life stages (e.g. neonates, juveniles, adult). Despite this, the main carcharhiniform taxa captured could be qualitatively categorised into four groups based on similar catch characteristics, body size and similarities in life history: small coastal ( mm) medium coastal (1000–2000 mm) large coastal/semi-pelagic ( mm) and hammerheads. Such groupings can potentially be useful for simplifying management of complex multispecies fisheries. The idiosyncrasies of elasmobranch populations and how fisheries interact with them provide a challenge for management but, if properly understood, potentially offer underutilised options for designing management strategies.
Publisher: Springer Science and Business Media LLC
Date: 25-10-2016
Publisher: Public Library of Science (PLoS)
Date: 06-2015
Publisher: Elsevier BV
Date: 2007
Publisher: CSIRO
Date: 2021
DOI: 10.25919/Y56N-1797
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 05-2017
Publisher: Inter-Research Science Center
Date: 07-12-2009
DOI: 10.3354/ESR00237
Publisher: CSIRO
Date: 2021
DOI: 10.25919/F3DT-HC97
Publisher: CSIRO
Date: 2022
DOI: 10.25919/1CF9-8315
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/MF09280
Abstract: Multiple readings of otoliths are often carried out to assess the repeatability and reliability of increment counts for estimating fish age. Various criteria have been used to assign or discard age estimates from repeated counts when discrepancies occur although the reasons for doing so are usually not stated or justified. Trends in relative frequencies (percentage disagreement, PD) and magnitudes (inter-read discrepancy, IRD) of otolith-count discrepancies were explored for 15 species of fish collected from a range of locations around Australia to explore generality in the best explanatory model(s) for otolith-count discrepancies and, hence, the most appropriate criterion for accepting or rejecting age estimates from multiple-count data. Increasing discrepancies with increasing age, according to a constant per-increment probability of error, was the best-approximating model for 9 of the 15 species for PD data but for only two species for IRD data. Our results indicated disproportionately higher rates of rejection of estimates from older age groups if exact agreement between repeated counts was required for age acceptance. Results varied with the reader, region and the method of otolith reading, indicating that multiple criteria for accepting or rejecting counts from multiple readings may be required among or even within species.
Publisher: Oxford University Press (OUP)
Date: 27-02-2020
Abstract: Minimizing fishing-induced mortality on bycatch and endangered, threatened or protected species is a necessity for fisheries managers. Estimating in idual vessel bycatch rates by iding the amount of bycatch by effort (nominal rate) can be biased, as it does not consider effort heterogeneity within the fleet and ignores prior knowledge of fleet bycatch rates. We develop an empirical Bayesian approach for estimating in idual vessel and fleet bycatch rates that: (i) considers effort heterogeneity among vessels and (ii) pools data from similar vessels for more accurate estimation. The proposed standardized bycatch rate of a vessel is, therefore, the weighted average of the pool rate and nominal rate of the vessel where the weights are functions of the vessel’s fishing effort and a constant estimated from the model. We apply this inference method to the estimation of seabird bycatch rates in the component of the Australian Eastern Tuna and Billfish Fishery targeting yellowfin tuna. We illustrate the capability of the method for providing fishery managers with insights on fleet-wide bycatch mitigation performance and the identification of outperforming and underperforming vessels. This method can also be used by fishery managers to develop fleet-wide performance measures or quantitative evaluation standards.
Publisher: Wiley
Date: 10-2007
Publisher: Elsevier BV
Date: 05-2007
Publisher: Canadian Science Publishing
Date: 03-2005
DOI: 10.1139/F04-237
Abstract: We investigate the use of multivariate life-history indices to assess the performance of no-take zones with respect to ameliorating the impacts of harvest on exploited coral reef fish populations in the Great Barrier Reef Marine Park. A range of life-history parameters were estimated for the two major target species of the Great Barrier Reef (GBR) line fishery, common coral trout (Plectropomus leopardus) and red throat emperor (Lethrinus miniatus), collected from five adjacent reefs (three of which were closed to all forms of fishing) in each of three geographically dispersed regions between 1995 and 1998. Life-history parameters were used to compare the status of populations on open and closed reefs over regions and years. Principal components (PC) analyses were used to effectively reduce the number of parameters to four significant PCs for each species, accounting for 84% and 94% of the total variation in the data for common coral trout and red throat emperor, respectively. We were able to clearly identify those populations that were s led from reefs open or closed to fishing based on the multivariate descriptors of life-history parameters. The concurrent use of several life-history indices maximised our potential to differentiate changes related to no-take zones from background variation.
Publisher: Wiley
Date: 05-2013
DOI: 10.1111/JFB.12077
Abstract: Validated estimates of age are presented for albacore Thunnus alalunga, s led from a large part of the south-western Pacific Ocean, based on counts of annual opaque growth zones from transverse sections of otoliths. Counts of daily increments were used to estimate the location of the first opaque growth zone, which was completed before the first assumed birthday. The periodicity of opaque zones was estimated by marginal increment analysis and an oxytetracycline mark-recapture experiment. Both validation methods indicated that opaque zones formed over the austral summer and were completed by autumn to winter (April to August). The direct comparison of age estimates obtained from otoliths and dorsal-fin spines of the same fish indicated bias, which was assumed to be due to poor increment clarity and resorption of early growth zones in spines, resulting in imprecise age estimates. As such, age estimates from otoliths are considered to be more accurate than those from spines for T. alalunga. This is consistent with results for a growing number of tropical and temperate tuna Thunnini species. It is recommend that validated counts of annual growth zones from sectioned otoliths is used as the preferred method for estimating age-based parameters for assessment and management advice for these important stocks.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 02-2019
Publisher: Public Library of Science (PLoS)
Date: 02-04-2013
Publisher: Elsevier BV
Date: 03-2015
Publisher: Frontiers Media SA
Date: 12-11-2020
Publisher: Public Library of Science (PLoS)
Date: 08-01-2014
Publisher: CSIRO
Date: 2022
DOI: 10.25919/AMV4-KB12
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/MF05127
Abstract: Uniformity in fish population biology is a common assumption in many fishery assessments and management arrangements. Although spatial patterns in population biology are often unknown, ignorance of significant variation within a fished stock has profound implications for fishery assessments and management. In the current paper, the reproductive biology of an exploited reef fish, Lethrinus miniatus, was examined for populations in the northern and southern regions of the Great Barrier Reef (GBR). Significant regional variation was observed in some reproductive parameters, but not others. In the northern region, the proportion of spawning females observed during the spawning season was significantly greater and the size at sex change significantly smaller than in the southern region. However, the spawning season, age at sex change and sex ratios did not differ significantly between the northern and southern regions. Size and age at maturity could not be estimated from either of these regions, but an estimate was obtained from the Capricorn–Bunker region at the southern tip of the GBR. The observed regional patterns in reproductive biology of L. miniatus populations have important implications for specific management arrangements such as size limits and seasonal closures, and for fisheries management in general.
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 09-2017
Publisher: Springer Science and Business Media LLC
Date: 29-08-2018
Publisher: Wiley
Date: 14-11-2022
DOI: 10.1111/FAF.12627
Abstract: Sharks (class Chondrichthyes, subclass Elasmobranchii) typically have a long lifespan, slow growth rate and low fecundity, leading to low productivity and hence relatively high vulnerability to fishing. Information for managing fisheries catches of elasmobranchs is often lacking, because elasmobranchs are usually non‐target species, often with low abundance. It is more feasible to develop management reference points for elasmobranchs based on their life‐history information than through traditional stock assessments. The natural mortality rate ( M ) is the leading life‐history parameter (LHP) required by many methods for developing reference points and is itself often derived indirectly from other LHPs. In this paper, we evaluate nine M estimators, using 15 shark stocks in the Western and Central Pacific Ocean as ex les. We then compare four methods for developing fishing mortality reference points F msy , including empirical modelling, the Euler‐Lotka equation, an M ‐productivity‐based method and the spawning potential rate converted method. Our analyses show that popular M estimators developed mainly from teleost data resulted in large deviations from the average and were not suitable for elasmobranchs. All four methods for estimating F msy performed similarly. However, the empirical method is very simple and cost‐effective and tended to produce smaller deviations from the average than the other three methods. Nonetheless, it is recommended that multiple methods should be used to minimize possible bias and reflect uncertainty, if the required LHPs are available.
Publisher: Wiley
Date: 07-08-2008
Publisher: Elsevier BV
Date: 07-2014
Publisher: Wiley
Date: 23-10-2011
Publisher: Elsevier BV
Date: 12-2009
Publisher: Wiley
Date: 03-2013
DOI: 10.1111/JFB.3495
Abstract: Life-history characteristics of six tropical Lethrinus species s led from the Great Barrier Reef World Heritage Area were compared. Two species groups were identified based on fork length (LF ): large species with maximum LF > 640 mm (longface emperor Lethrinus olivaceus, yellowlip emperor Lethrinus xanthochilus and spangled emperor Lethrinus nebulosus) and small species with maximum LF < 480 mm (Pacific yellowtail emperor Lethrinus atkinsoni, pink ear emperor Lethrinus lentjan and ornate emperor Lethrinus ornatus). Lifespan was not correlated with LF . Early growth for all species was rapid and similar during the first few years of life, but coefficients of the von Bertalanffy growth function varied considerably among species. Growth also differed between sexes for L. atkinsoni. Reproductive characteristics varied among species, with peak periods of spawning occurring in November to December for L. atkinsoni, July to August for L. nebulous, September to October for L. olivaceus and a protracted season for L. lentjan, although fewer s les were available for the last two species. Sex-specific LF and age distributions and gonad histology of L. lentjan were suggestive of a functional protogynous reproductive pattern, as observed in other lethrinids. Gonad histology indicated non-functional protogynous hermaphroditism for L. atkinsoni and L. nebulosus. The ersity of life histories among these closely related species emphasizes the difficulty in devising single management strategies appropriate for multi-species fisheries and illustrates the importance of understanding species-specific life histories to infer responses to exploitation.
Publisher: Springer Science and Business Media LLC
Date: 25-06-2015
Publisher: Wiley
Date: 08-2009
DOI: 10.1111/J.1095-8649.2009.02313.X
Abstract: Using the ratio of the number of migratory nuclei to hydrated oocytes to estimate batch fecundity of common coral trout Plectropomus leopardus increases the time over which s les can be collected and, therefore, increases the s le size available and reduces biases in batch fecundity estimates.
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 06-2019
Publisher: NMFS Publications Office
Date: 22-11-2019
DOI: 10.7755/FB.117.4.5
Publisher: Elsevier BV
Date: 02-2019
Publisher: CSIRO
Date: 2022
DOI: 10.25919/K3ZY-D186
Publisher: Inter-Research Science Center
Date: 08-06-2015
DOI: 10.3354/MEPS11277
Publisher: Oxford University Press (OUP)
Date: 29-09-2016
Abstract: Tropical deep-water snappers (Etelinae) support valuable fisheries across the Indo-Pacific, with stock assessments reliant on age-based information in the absence of reliable catch and effort statistics. These long-lived species have been considered notoriously difficult to age. However, nascent developments in ageing protocols, particularly thinner transverse sections of otoliths (∼180–200 µm), are providing improvements in growth zone clarity, interpretation and repeatability of annuli counts. At a recent international workshop, thin sectioned otoliths from three deep-water snappers were read under reflected light by eight fisheries scientists from across the Indo-Pacific, with various levels of fish-ageing experience. Precision and bias were assessed using traditional ageing precision metrics (index of average percent error, IAPE and coefficient of variation, CV), and a novel approach using multivariate analyses (metric multidimensional scaling, mMDS) based on Euclidean dissimilarity among readers’ counts and subsequent von Bertalanffy (vB) growth parameter estimates. Annuli counts between the primary reader and all other readers were within two for 80% of estimates, with uniform variation across a wide age range for Etelis carbunculus (intraclass correlation coefficient (ICC) = 0.924, n = 20, 3–25 annuli) and Etelis sp. (ICC = 0.933, n = 15, 2–27 annuli). In contrast, annuli counts for Pristipomoides filamentosus (n = 14, 4–49) were less precise (i.e. ICC = 0.835, 66% of counts within two of primary reader) with a bias toward greater variation in younger, pre-maturational life stages (≤5 annuli). Traditionally accepted ageing precision (IAPE ≤ 5.5%, CV ≤ 7.6%) was achieved for each species, but was commensurate with reader experience. The multivariate mMDS ordination was more informative in identifying both distance (i.e. dissimilarity) and direction (i.e. form) of variations in annuli counts and vB growth parameter estimates among readers. The acceptable level of ageing precision and bias achieved among most readers indicated that deep-water snappers can be aged precisely when appropriate otolith preparation methods are used. This study contributes towards ageing protocols that can be used to (i) interrogate bias and precision of age data for stock assessments, and (ii) standardise comparisons of age-based life history characteristics across a species range.
Publisher: Springer Science and Business Media LLC
Date: 29-08-2017
DOI: 10.1038/S41598-017-10180-W
Abstract: No-take marine reserves (NTMRs) are expected to benefit fisheries via the net export of eggs and larvae (recruitment subsidy) from reserves to adjacent fished areas. Quantifying egg production is the first step in evaluating recruitment subsidy potential. We calculated annual egg production per unit area (EPUA) from 2004 to 2013 for the commercially important common coral trout, Plectropomus leopardus , on fished and NTMR reefs throughout the Great Barrier Reef (GBR), Australia. Geographic region, NTMR status, fish size, and population density were all found to affect EPUA. The interactions among these factors were such that, EPUA on NTMR reefs compared to reefs open to fishing was 21% greater in the southern GBR, 152% greater in the central GBR, but 56% less in the northern GBR. The results show that while NTMRs can potentially provide a substantial recruitment subsidy (central GBR reefs), they may provide a far smaller subsidy (southern GBR), or serve as recruitment sinks (northern GBR) for the same species in nearby locations where demographic rates differ. This study highlights the importance of considering spatial variation in EPUA when assessing locations of NTMRs if recruitment subsidy is expected from them.
Publisher: CSIRO
Date: 2021
DOI: 10.25919/G0E5-PB32
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 09-2008
Publisher: American Chemical Society (ACS)
Date: 13-05-2019
Publisher: Elsevier BV
Date: 12-2018
Publisher: Springer Science and Business Media LLC
Date: 06-07-2016
Publisher: Springer Science and Business Media LLC
Date: 23-03-2016
Publisher: Elsevier BV
Date: 09-2008
Publisher: Springer Science and Business Media LLC
Date: 17-05-2014
Publisher: CSIRO
Date: 2022
DOI: 10.25919/XQTS-F816
Publisher: CSIRO
Date: 2021
DOI: 10.25919/R7E5-8C34
Publisher: Oxford University Press (OUP)
Date: 05-2011
Abstract: Williams, A. J., Little, L. R., and Begg, G. A. 2011. Balancing indigenous and non-indigenous commercial objectives in a coral reef finfish fishery. – ICES Journal of Marine Science, 68: 834–847. Indigenous participation in commercial fisheries is poorly established in Australia, except in Torres Strait where indigenous and non-indigenous commercial fishers participate in the Torres Strait Finfish Fishery (TSFF). TSFF stakeholders helped identify specific objectives and alternative management strategies for the fishery at a time when new management strategies were under consideration. A metapopulation and fishing simulation model was used to evaluate alternative management strategies related to harvest and conservation of coral trout (Plectropomus spp.), the main target species. Stakeholders identified objectives relating to conservation of unfished populations, maintenance of harvestable stock, and economic performance. In terms of management options, spatial closures decreased the prospects of meeting nearly all stakeholder objectives. A seasonal closure and larger minimum capture size increased the probability of meeting conservation and harvest objectives, but decreased the probability of meeting most economic objectives for both sectors. Increasing fishing effort increased harvest but decreased the catch rates for both sectors, so had varied effects on the probability of achieving harvest objectives. The research provides a case study of productive engagement with indigenous and non-indigenous stakeholders to address fisheries management needs and provides a framework for impartial evaluation of performance of alternative management strategies against stakeholder objectives.
Publisher: CSIRO
Date: 2021
DOI: 10.25919/HVK8-WT73
Publisher: Public Library of Science (PLoS)
Date: 19-06-2012
Publisher: Springer Science and Business Media LLC
Date: 29-09-2015
Publisher: Elsevier BV
Date: 09-2008
Publisher: Springer Science and Business Media LLC
Date: 13-04-2016
Publisher: Springer Science and Business Media LLC
Date: 27-07-2014
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 12-2018
Publisher: Oxford University Press (OUP)
Date: 06-08-2013
Abstract: Williams, A. J., Leroy, B. M., Nicol, S. J., Farley, J. H., Clear, N. P., Krusic-Golub, K., and Davies, C. R. Comparison of daily- and annual-increment counts in otoliths of bigeye (Thunnus obesus), yellowfin (T. albacares), southern bluefin (T. maccoyii) and albacore (T. alalunga) tuna. – ICES Journal of Marine Science, 70: . Information on the age of in iduals is often required for models assessing the status of stocks. Techniques used to estimate age of tuna have varied across species and agencies, precluding meta-analyses of age and growth. We compared age estimates obtained from commonly used ageing techniques for four important tuna species: bigeye tuna, yellowfin tuna, southern bluefin tuna, and albacore tuna. Estimates of age from counts of annual increments in transverse-sectioned otoliths were generally higher than those from counts of daily increments in transverse and longitudinal sections for all species, particularly for fish older than two years. However, annual counts produced younger estimates, on average, relative to daily counts for bigeye and yellowfin tuna younger than one year. Estimates derived from daily increments in longitudinal and transverse sections were generally similar, although longitudinal sections produced relatively older age estimates for in iduals older than two years. A linear or non-linear increase in the magnitude of differences between ageing methods was the best-approximating model in all cases except when comparing daily-increment counts between transverse and longitudinal otolith sections for southern bluefin tuna. These observations are consistent with a narrowing of daily increments with increasing age, resulting in underestimates of age relative to those derived from annual increments. We conclude that (i) daily increments are unsuitable for ageing in iduals over two years, especially for southern bluefin and albacore, (ii) longitudinal sections are more precise and produce older age estimates than transverse sections for daily-age estimates, (iii) there are considerable differences in these trends between species, likely dependent on longevity, and (iv) parameter estimates and/or conclusions based on meta-analyses using age data derived from different ageing methods are likely confounded with methodological biases. This result demonstrates that greater effort is required to provide consistent, validated methods for routine age determination to support the assessment and management of these valuable populations.
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/MF07112
Abstract: A commonly used approach to quantifying growth is to fit mathematical models to length-at-age data. Growth of the silver-lip pearl oysters, Pinctada maxima, cultured at a commercial pearl farm in West Papua, Indonesia was expressed mathematically by fitting five growth models (Gompertz, Richards, Logistic, Special von Bertalanffy Growth Function (VBGF) and General VBGF) to length-at-age data. The criteria used to determine the best fit model were a low mean residual sum of squares (MRSS), high coefficient of determination (r2) and low deviation of the asymptotic length (L∞) from the maximum length (Lmax). Using these criteria, the models were ranked accordingly: Special VBGF General VBGF Gompertz Richards and Logistic models. The Special VBGF yielded the best fit (L∞ = 168.38 mm K = 0.930 year–1 t0 = 0.126 MRSS = 208.64 r2 = 0.802 Deviation of L∞ from Lmax = 37.52 mm) and, accordingly, was used to model the growth of oysters cultured at three sites and two depths within the farm. Likelihood ratio tests were used to compare growth of oysters cultured at these sites and depths. Based on L∞ and K values, favourable sites and depths could be determined that optimised growth requirements for the various stages of P. maxima culture. Sites with high K and L∞ values were preferred sites for culturing juvenile oysters before pearl production, when high growth rate is essential to produce large numbers of oysters in the shortest time possible. In addition, high L∞ may facilitate implantation of larger nuclei conducive to the production of larger, more valuable pearls. Conversely, sites with low K values were preferred sites for weakening P. maxima before pearl ‘seeding’, a process undertaken to minimise nucleus rejection after seeding.
Publisher: Oxford University Press (OUP)
Date: 24-03-2020
Abstract: Risks to deepwater chondrichthyans (sharks, rays, and chimaeras) from fishing are poorly understood, particularly in areas beyond national jurisdiction. We adapted productivity–susceptibility analysis (PSA) and sustainability assessment for fishing effects (SAFE) to assess the vulnerability of 173 deepwater chondrichthyans to various demersal fishing gears in the Southern Indian and South Pacific Oceans. Several species were categorized as being at high or extreme vulnerability, including some deepwater shark species in the Southern Indian Ocean that are reported to be commercially targeted. There was good concurrence between PSA and SAFE results for species categorized as being at high or extreme vulnerability by the SAFE, but as expected there was an overall greater number assessed to be as higher vulnerability using PSA due to its precautionary nature. Our results indicate probable misclassifications in the PSA relative vulnerability rankings, highlighting the value of applying more quantitative tools, such as SAFE, when adequate data are available. Our findings indicate that better catch, effort, and biological information are needed to inform the assessment and management of deepwater chondrichthyans. If targeted fishing of deepwater shark species continues in the Southern Indian Ocean, improved assessments and estimates of sustainable yields are urgently required to mitigate the risk of overexploitation.
Publisher: Elsevier BV
Date: 03-2014
Publisher: Elsevier BV
Date: 10-2020
Publisher: Oxford University Press (OUP)
Date: 15-03-2015
Abstract: Deepwater snappers (Family Lutjanidae) are important to artisanal and subsistence fisheries in Pacific Island countries. Most species of deepwater snapper are considered vulnerable to exploitation due to their extended longevity and low natural mortality rates. However, the sustainability of deepwater snapper fisheries in Pacific Island countries remains uncertain because there are limited resources available to collect the required data for comprehensive stock assessments. Reliable estimates of the age composition for exploited deepwater snapper populations are limited primarily because of the lack of skills and resources required for routine age estimation from sectioned otoliths. The development of alternative low-cost approaches to derive estimates of age for deepwater snappers is required. We evaluated the performance of using otolith morphometrics (weight, length, width, and thickness) to obtain estimates of age for the most important target species in these fisheries: Etelis carbunculus, E. marshi, E. coruscans, and Pristipomoides filamentosus. We compared age compositions and fishing mortality rates (F) derived from otolith morphometrics with those derived from counts of annual increments in otoliths. We then used the ratio of F to natural mortality (M) as a biological indicator to evaluate the potential effects on management responses by comparing estimates of F/M derived from otolith morphometrics with those derived from annual increment counts. Age compositions and estimates of F and F/M did not differ significantly between those derived from otolith morphometrics and those derived from annual increment counts for all species. These results demonstrate that management responses would likely be similar whether based on age estimates derived from sectioned otoliths, or predicted from otolith morphometrics. In the absence of sufficient resources to section otoliths for age estimation, we recommend that otolith morphometrics be used as a proxy for age in assessments of deepwater snapper fisheries in Pacific Island countries, and potentially for other similar data-limited fisheries.
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/MF09056
Abstract: Species in the coral trout complex Plectropomus spp. are some of the most desired and exploited in the Indo-Pacific, although data are limited for most species. Demographic parameters of blue-spot coral trout, Plectropomus laevis, were estimated on the basis of specimens collected from five regions of the Great Barrier Reef and Torres Strait, Australia, between 1995 and 2005 to define demography and population status over a broad range. In total, 1249 in iduals were collected to estimate growth, mortality and reproductive parameters. Growth parameters based on the von Bertalanffy model were K = 0.096 year–1, L∞ = 1159 mm fork length (FL) and the best-fit model suggested non-asymptotic growth over the size and age ranges represented in the s le. Maximum age was 16 years, total mortality was estimated at 0.39 (±0.031), and estimated size and age at first maturity were 299 mm FL (range: 299–872) and at 1 year (range: 1–6.5), respectively, with the size range over which sex change occurred at 460–872 mm FL. Population parameters and available relative abundance estimates indicated that long-term sustainable harvest rates of P. laevis will be lower than those for P. leopardus and species-specific size-based management measures are necessary to ensure the species is not overfished.
Publisher: Wiley
Date: 07-2001
Publisher: Australian Ocean Data Network
Date: 2021
DOI: 10.26198/X7H1-KG97
Publisher: Frontiers Media SA
Date: 18-12-2017
Publisher: Hindawi Limited
Date: 10-01-2013
DOI: 10.1111/JAI.12123
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 03-2016
Publisher: CSIRO
Date: 2022
DOI: 10.25919/PC4S-7P98
Publisher: Inter-Research Science Center
Date: 29-04-2010
DOI: 10.3354/MEPS08527
Publisher: Elsevier BV
Date: 12-2008
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.YMPEV.2016.04.004
Abstract: Evolutionary genetic patterns in shallow coastal fishes are documented with dozens of studies, but corresponding surveys of deepwater fishes (>200m) are scarce. Here we investigate the evolutionary history of deepwater snappers (genus Etelis), comprised of three recognized Indo-Pacific species and one Atlantic congener, by constructing a phylogeny of the genus with two mtDNA loci and two nuclear introns. Further, we apply range-wide Indo-Pacific s ling to test for the presence and distribution of a putative cryptic species pair within E. carbunculus using morphological analyses and mtDNA cytochrome b sequences from 14 locations across the species range (N=1696). These analyses indicate that E. carbunculus is comprised of two distinct, non-interbreeding lineages separated by deep ergence (d=0.081 in cytochrome b). Although these species are morphologically similar, we identified qualitative differences in coloration of the upper-caudal fin tip and the shape of the opercular spine, as well as significant differences in adult body length, body depth, and head length. These two species have overlapping Indo-Pacific distributions, but one species is more widespread across the Indo-Pacific, whereas the other species is documented in the Indian Ocean and Western Central Pacific. The dated Etelis phylogeny places the cryptic species ergence in the Pliocene, indicating that the biogeographic barrier between the Indian and Pacific Oceans played a role in speciation. Based on historic taxonomy and nomenclature, the species more widespread in the Pacific Ocean is E. carbunculus, and the other species is previously undescribed (referred to here as E. sp.). The Atlantic congener E. oculatus has only recently (∼0.5Ma) erged from E. coruscans in the Indo-Pacific, indicating colonization via southern Africa. The pattern of ergence at the Indo-Pacific barrier, and Pleistocene colonization from the Indian Ocean into the Atlantic, is concordant with patterns observed in shallow coastal fishes, indicating similar drivers of evolutionary processes.
Publisher: Wiley
Date: 16-05-2022
DOI: 10.1111/JFB.15059
Abstract: Marine resources are often shared among countries, with some fish stocks straddling multiple Exclusive Economic Zones, therefore understanding the structure of populations is important for the effective management of fish stocks. Otolith chemical analyses could discriminate among populations based on differences in the chemical composition of otoliths. We used otoliths from two deepwater snappers (flame snapper Etelis coruscans and ruby snapper Etelis boweni ) to examine the evidence for population structure across six Pacific Island countries using solution‐based inductively coupled plasma mass spectrometry (ICP‐MS) for otolith core and whole otolith s les and laser ablation ICP‐MS (LA‐ICP‐MS) for core and edge areas of a cross‐sectioned otolith. The inter‐species comparison of these methods is important as the two species are often managed under the same regulations. For both species, the two methods demonstrated separation among the locations s led with high classification accuracy. Smaller laser ablation spot size gave greater temporal resolution over the life‐history transect. Comparing the early life‐history section of the otoliths ( i.e. , the core), one interpretation is that young fish experienced more uniform environments in the open ocean as larvae than adults, as the elemental fingerprints had greater overlap among multiple locations. LA‐ICP‐MS methods had some advantages over solution‐based ICP‐MS and generally better discrimination for the trace elements investigated. There were substantial differences between species, but both methods suggested nonmixing populations at the regional scale. Otolith chemistry can be an effective tool in discriminating variation for deepwater marine species in multispecies fisheries, and edge measurements from LA‐ICP‐MS provided the greatest resolution. Although caution should be taken in interpreting the results from relatively small s les sizes, otolith chemical analyses could be useful at these spatial scales to investigate population structure. This information on separate or overlapping populations could be used in future regional fishery management plans.
Publisher: Wiley
Date: 02-2003
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/MF04129
Abstract: Marginal increment analysis was used to validate the periodicity of opaque increment formation in red throat emperor (Lethrinus miniatus) otoliths and to test for variation in the periodicity and timing of increment formation across age classes, years and regions of the Great Barrier Reef (GBR). Marginal increment analysis demonstrated that opaque increments were deposited on an annual basis, a result supported by a preliminary experiment on a chemically tagged captive fish, although significant regional and temporal variation in the timing of increment formation was observed. Marginal increment analysis revealed a clear annual periodicity in increment formation for all age classes in the southern region but a more ambiguous pattern for most age classes in the northern region of the species distribution on the GBR. Opaque increments appeared to form 1 month earlier in the southern region than in the northern region and, in the southern region, formed 2 months earlier in 1999 than in 2000. No significant variation was observed in the timing of increment formation between age classes. Based on knowledge of the timing of otolith increment formation and spawning season of L. miniatus, an algorithm was developed for the estimation of age in months, irrespective of the time or location of capture.
Publisher: Wiley
Date: 18-03-2014
DOI: 10.1111/JFB.12346
Abstract: The effects of size and age on reproductive dynamics of common coral trout Plectropomus leopardus populations were compared between coral reefs open or closed (no-take marine reserves) to fishing and among four geographic regions of the Great Barrier Reef (GBR), Australia. The specific reproductive metrics investigated were the sex ratio, the proportion of vitellogenic females and the spawning fraction of local populations. Sex ratios became increasingly male biased with length and age, as expected for a protogyne, but were more male biased in southern regions of the GBR (Mackay and Storm Cay) than in northern regions (Lizard Island and Townsville) across all lengths and ages. The proportion of vitellogenic females also increased with length and age. Female P. leopardus were capable of daily spawning during the spawning season, but on average spawned every 4·3 days. Mature females spawned most frequently on Townsville reserve reefs (every 2·3 days) and Lizard Island fished reefs (every 3·2 days). Females on Mackay reefs open to fishing showed no evidence of spawning over 4 years of s ling, while females on reserve reefs spawned only once every 2-3 months. No effect of length on spawning frequency was detected. Spawning frequency increased with age on Lizard Island fished reefs, declined with age on Storm Cay fished reefs, and declined with age on reserve reefs in all regions. It is hypothesized that the variation in P. leopardus sex ratios and spawning frequency among GBR regions is primarily driven by water temperature, while no-take management zones influence spawning frequency depending on the region in which the reserve is located. Male bias and lack of spawning activity on southern GBR, where densities of adult P. leopardus are highest, suggest that recruits may be supplied from central or northern GBR. Significant regional variation in reproductive traits suggests that a regional approach to management of P. leopardus is appropriate and highlights the need for considering spatial variation in reproduction where reserves are used as fishery or conservation management tools.
Location: Australia
No related grants have been discovered for Ashley Williams.