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Articles 1 - 30 of 33
Full-Text Articles in Physical Sciences and Mathematics
A Sparse Implementation Of The Average Information Algorithm For Factor Analytic And Reduced Rank Variance Models, R Thompson, Brian Cullis, A Smith, Arthur Gilmour
A Sparse Implementation Of The Average Information Algorithm For Factor Analytic And Reduced Rank Variance Models, R Thompson, Brian Cullis, A Smith, Arthur Gilmour
Professor Brian Cullis
Factor analytic variance models have been widely considered for the analysis of multivariate data particularly in the psychometrics area. Recently Smith, Cullis & Thompson (2001) have considered their use in the analysis of multi-environment data arising from plant improvement programs. For these data, the size of the problem and the complexity of the variance models chosen to account for spatial heterogeneity within trials implies that standard algorithms for fitting factor analytic models can be computationally expensive. This paper presents a sparse implementation of the average information algorithm (Gilmour, Thompson & Cullis, 1995) for fitting factor analytic and reduced rank variance …
Anisotropic Matern Correlation And Spatial Prediction Using Reml, K A. Haskard, Brian R. Cullis, A P. Verbyla
Anisotropic Matern Correlation And Spatial Prediction Using Reml, K A. Haskard, Brian R. Cullis, A P. Verbyla
Professor Brian Cullis
The Mat´ern correlation function provides great flexibility for modeling spatially correlated random processes in two dimensions, in particular via a smoothness parameter, whose estimation allows data to determine the degree of smoothness of a spatial process. The extension to include anisotropy provides a very general and flexible class of spatial covariance functions that can be used in a model-based approach to geostatistics, in which parameter estimation is achieved via REML and prediction is within the E-BLUP framework. In this article we develop a general class of linear mixed models using an anisotropic Mat´ern class with an extended metric. The approach …
Joint Modeling Of Additive And Non-Additive Genetic Line Effects In Single Field Trials, H Oakey, A Verbyla, Brian Cullis, W. Pitchford, H. Kuchel
Joint Modeling Of Additive And Non-Additive Genetic Line Effects In Single Field Trials, H Oakey, A Verbyla, Brian Cullis, W. Pitchford, H. Kuchel
Professor Brian Cullis
A statistical approach is presented for selection of best performing lines for commercial release and best parents for future breeding programs from standard agronomic trials. The method involves the partitioning of the genetic effect of a line into additive and non-additive effects using pedigree based inter-line relationships, in a similar manner to that used in animal breeding. A difference is the ability to estimate non-additive effects. Line performance can be assessed by an overall genetic line effect with greater accuracy than when ignoring pedigree information and the additive effects are predicted breeding values. A generalized definition of heritability is developed …
Multivariate Whole Genome Average Interval Mapping: Qtl Analysis For Multiple Traits And/Or Environments, Arunas P. Verbyla, Brian R. Cullis
Multivariate Whole Genome Average Interval Mapping: Qtl Analysis For Multiple Traits And/Or Environments, Arunas P. Verbyla, Brian R. Cullis
Professor Brian Cullis
A major aim in some plant-based studies is the determination of quantitative trait loci (QTL) for multiple traits or across multiple environments. Understanding these QTL by trait or QTL by environment interactions can be of great value to the plant breeder. A whole genome approach for the analysis of QTL is presented for such multivariate applications. The approach is an extension of whole genome average interval mapping in which all intervals on a linkage map are included in the analysis simultaneously. A random effects working model is proposed for the multivariate (trait or environment) QTL effects for each interval, with …
Long-Term Liming Regime Increases Prime Lamb Production On Acid Soils, G Chen, G D. Li, M K. Conyers, B R. Cullis
Long-Term Liming Regime Increases Prime Lamb Production On Acid Soils, G Chen, G D. Li, M K. Conyers, B R. Cullis
Professor Brian Cullis
Prime lamb live weight response to lime application on pasture was measured in a grazing experiment in the high rainfall zone of the southwestern slopes of New South Wales, Australia. The pastures were limed every 6 years over 15 years. First cross South African Meat Merino lambs were used as test animals. Preand post-grazing pasture dry matter (DM) yield, botanical composition, feed quality and lamb live weight were monitored over 12 weeks in 2007. Results showed that liming significantly increased pastureDMyield of high quality species and improved overall pasture quality due to increased digestibility and metabolic energy content. As a …
Assessing Barotrauma Among Angled Snapper (Pagrus Auratus) And The Utility Of Release Methods, Paul Butcher, Matt Broadhurst, Karina Hall, Brian Cullis, Shane Raidal
Assessing Barotrauma Among Angled Snapper (Pagrus Auratus) And The Utility Of Release Methods, Paul Butcher, Matt Broadhurst, Karina Hall, Brian Cullis, Shane Raidal
Professor Brian Cullis
Australian recreational and commercial fishers catch snapper (Pagrus auratus) from down to 120 m, often evoking barotrauma. Owing to minimum legal sizes and quotas or non-consumptive fishing practices, some afflicted fish are released, raising concerns over the potential for unaccounted fishing mortality. Two experiments were completed to quantify the (1) clinical signs of barotrauma among fish angled from 6 to 120 m (experiment 1) and (2) mortality (over 3 d) of fish with barotrauma that were released following either no treatment, venting (e.g. needle) or recompression (e.g. release weight) (experiment 2). In experiment 1, barotrauma was evident in some fish …
Pasture And Sheep Responses To Lime Application In A Grazing Experiment In A High-Rainfall Area, South-Eastern Australia. Ii. Liveweight Gain And Wool Production, G. Li, K. Helyar, M. Conyers, L. Castleman, R. Fisher, G Poile, C Lisle, Brian Cullis, P. Cregan
Pasture And Sheep Responses To Lime Application In A Grazing Experiment In A High-Rainfall Area, South-Eastern Australia. Ii. Liveweight Gain And Wool Production, G. Li, K. Helyar, M. Conyers, L. Castleman, R. Fisher, G Poile, C Lisle, Brian Cullis, P. Cregan
Professor Brian Cullis
‘Managing Acid Soils Through Efficient Rotations (MASTER)’ is a long-term pasture–crop rotation experiment commenced in 1992. One of the objectives was to demonstrate the extent of crop, pasture, and animal responses to lime application on a typical acidic soil in the 500–800 mm rainfall zone of south-eastern Australia. Two types of pastures (perennial v. annual pastures) with or without lime application were established in 1992. Fifteen- to eighteen-month-old Merino hoggets were used as test animals and were changed annually. This paper reports the results of sheep responses to liming from the 4 continuous pasture treatments over 6 years from 1992 …
Comparison Of Small-Scale And Large-Scale Mixing Characteristics: Correlations Between Small-Scale And Large-Scale Mixing And Extensional Characteristics Of Wheat Flour Dough, Helen Allen, Simon Diffey, Allen H, Zena Pumpa, Simon Nath, Jennifer Morell, Gulay Cullis, Alison Smith
Comparison Of Small-Scale And Large-Scale Mixing Characteristics: Correlations Between Small-Scale And Large-Scale Mixing And Extensional Characteristics Of Wheat Flour Dough, Helen Allen, Simon Diffey, Allen H, Zena Pumpa, Simon Nath, Jennifer Morell, Gulay Cullis, Alison Smith
Professor Brian Cullis
measurements provide valuable information about dough strength and stability (STAB) traits. These measurements are important in milling and baking operations, and for varietal selection in wheat breeding programmes. There are several techniques with different sample sizes used for measuring these traits so there is interest in examining the agreement between methods in terms of genotypic (varietal) rankings. This issue has been investigated by using two different mixing methods, a small-scale Mixograph (2 g) and large-scale Farinograph (50 g) using data from a doubled haploid population (190 lines) from a Chara (excellent dough strength)×WW2449 (poor dough strength) cross. The cross was …
Embedded Partially Replicated Designs For Grain Quality Testing, Alison B. Smith, Robin Thompson, Brian R. Cullis
Embedded Partially Replicated Designs For Grain Quality Testing, Alison B. Smith, Robin Thompson, Brian R. Cullis
Professor Brian Cullis
The literature on the design and analysis of cereal variety trials has focussed on the trait of grain yield. Such trials are also used to obtain information on grain quality traits but these are rarely subjected to the same level of statistical rigour. The data are often obtained using composite rather than individual replicate samples. This precludes the use of an efficient statistical analysis. In this paper we propose an approach in which a proportion of varieties is grain quality tested using individual replicate samples. This is achieved by embedding a partially replicated design (for measuring quality traits) within a …
On The Design Of Early Generation Variety Trials With Correlated Data, Brian Cullis, A Smith, N. Coombes
On The Design Of Early Generation Variety Trials With Correlated Data, Brian Cullis, A Smith, N. Coombes
Professor Brian Cullis
This article considers the design of early generation variety trials with a prespecified spatial correlation structure and introduces a new class of partially replicated designs called p-rep designs in which the plots of standard varieties are replaced by additional plots of test lines. We show how efficient p-rep designs can be readily generated using the modified Reactive TABU search algorithm. The expected and realized genetic gain of p-rep and grid plot designs is compared in a simulation study.
The Analysis Of Longitudinal Data Using Mixed Model L-Splines, S. Welham, Brian Cullis, M. Kenward, R Thompson
The Analysis Of Longitudinal Data Using Mixed Model L-Splines, S. Welham, Brian Cullis, M. Kenward, R Thompson
Professor Brian Cullis
L-splines are a large family of smoothing splines defined in terms of a linear differential operator. This article develops L-splines within the context of linear mixed models and uses the resulting mixed model L-spline to analyze longitudinal data from a grassland experiment. In the spirit of time-series analysis, a periodic mixed model L-spline is developed, which partitions data into a smooth periodic component plus smooth long-term trend.
Effects Of Otter Boards On Catches Of An Australian Penaeid Trawl, Matt Broadhurst, David Sterling, Brian Cullis
Effects Of Otter Boards On Catches Of An Australian Penaeid Trawl, Matt Broadhurst, David Sterling, Brian Cullis
Professor Brian Cullis
The effects of otter boards on the catches of Metapenaeus macleayi were quantified within the broad aim of promoting more hydrodynamic and environmentally benign trawl-spreading mechanisms. Two identical trawls (7.26 m footropes) were attached to 2.89-m sweeps and simultaneously fished in a double-rig; each alternately attached to either two otter boards or a rigid 6.0-m beam with parallel sleds (configured not to impact on the behaviour of M. macleayi). Both trawl configurations had the same total weight (143 kg) and initial wing-end spreads (predicted means of 4.33 and 4.45 m), although the otter boards caused significantly more variable wing-end spread …
On Spatial Prediction Of Soil Properties In The Presence Of A Spatial Trend: The Empirical Best Linear Unbiased Predictor (E-Blup) With Reml, R Lark, B Cullis, S Welham
On Spatial Prediction Of Soil Properties In The Presence Of A Spatial Trend: The Empirical Best Linear Unbiased Predictor (E-Blup) With Reml, R Lark, B Cullis, S Welham
Professor Brian Cullis
Geostatistical estimates of a soil property by kriging are equivalent to the best linear unbiased predictions (BLUPs). Universal kriging is BLUP with a fixed-effect model that is some linear function of spatial coordinates, or more generally a linear function of some other secondary predictor variable when it is called kriging with external drift. A problem in universal kriging is to find a spatial variance model for the random variation, since empirical variograms estimated from the data by method-of-moments will be affected by both the random variation and that variation represented by the fixed effects. The geostatistical model of spatial variation …
Towards Genomic Selection In Oilseed Brassica, Wallace Cowling, Brian Cullis, Cameron Beeck, Matthew Nelson
Towards Genomic Selection In Oilseed Brassica, Wallace Cowling, Brian Cullis, Cameron Beeck, Matthew Nelson
Professor Brian Cullis
Animal breeders have paved the way for plant breeders to adopt the principles of association genetics to improve the rate of genetic progress in breeding programs. The total genetic value of an individual may be predicted from genome-wide markers in a process known as genomic selection. Analysis of a series of canola breeding trials by factor analytic modeling has demonstrated the value of including ancestral pedigree relationships for estimating additive and non-additive effects in a range of environments, and for modeling genotype by environment effects. In theory, this may be developed into genomic selection based on whole-genome markers in Brassica …
Effects Of Novel Hybrid And Traditional Rootstocks On Vigour And Yield Components Of Shiraz Grapevines, T H. Jones, B R. Cullis, P R. Clingeleffer, E H. Ruhl
Effects Of Novel Hybrid And Traditional Rootstocks On Vigour And Yield Components Of Shiraz Grapevines, T H. Jones, B R. Cullis, P R. Clingeleffer, E H. Ruhl
Professor Brian Cullis
Background and Aims: The influence of grapevine rootstocks on vine vigour and crop yield is recognized as an integral part of viticultural management. However, the genetic potential of Vitis species rootstock hybrids for vigour and yield control is not fully exploited in Australian viticulture. The effect of 55 novel inter- and intra-species hybrids and five traditional hybrid rootstock cultivars on winter pruning weight, berry size and fruit yield of grafted Shiraz vines is presented. The genetic predictions that resulted from this analysis were used to illustrate how rootstocks that best perform for a combination of traits may be selected. Methods …
Improving The Accuracy Of Selection For Late Maturity A-Amylase In Wheat Using Multi-Phase Designs, D Butler, M Tan, B Cullis
Improving The Accuracy Of Selection For Late Maturity A-Amylase In Wheat Using Multi-Phase Designs, D Butler, M Tan, B Cullis
Professor Brian Cullis
The assessment of grain defect traits is assuming greater importance in wheat germplasm selection. Late maturity a-amylase is one such characteristic that renders wheat unsuitable for high value end products, even though the grain may appear sound. Phenotyping defect traits typically involves a multi-phase process, where genetic material for assay has been affected by non-genetic sources of variation in one or more previous linked stages of experimentation or preparation. The adoption of appropriate statistical design and analysis methods in these situations is, however, not widespread. Substantial sources of non-genetic variation were identified in the analysis of a designed experiment to …
Joint Modeling Of Additive And Non-Additive (Genetic Line) Effects In Multi-Environment Trials, H Oakey, A Verbyla, Brian Cullis, X. Wei, W. Pitchford
Joint Modeling Of Additive And Non-Additive (Genetic Line) Effects In Multi-Environment Trials, H Oakey, A Verbyla, Brian Cullis, X. Wei, W. Pitchford
Professor Brian Cullis
A statistical approach for the analysis of multienvironment trials (METs) is presented, in which selection of best performing lines, best parents, and best combination of parents can be determined. The genetic effect of a line is partitioned into additive, dominance and residual nonadditive effects. The dominance effects are estimated through the incorporation of the dominance relationship matrix, which is presented under varying levels of inbreeding. A computationally efficient way of fitting dominance effects is presented which partitions dominance effects into between family dominance and within family dominance line effects. The overall approach is applicable to inbred lines, hybrid lines and …
A Comparison Of Mixed Model Splines For Curve Fitting, S Welham, Brian Cullis, M Kenward, R Thompson
A Comparison Of Mixed Model Splines For Curve Fitting, S Welham, Brian Cullis, M Kenward, R Thompson
Professor Brian Cullis
Three types of polynomial mixed model splines have been proposed: smoothing splines, Psplines and penalized splines using a truncated power function basis. The close connections between these models are demonstrated, showing that the default cubic form of the splines differs only in the penalty used. A general definition of the mixed model spline is given that includes general constraints and can be used to produce natural or periodic splines. The impact of different penalties is demonstrated by evaluation across a set of functions with specific features, and shows that the best penalty in terms of mean squared error of prediction …
An Examination Of The Efficiency Of Australian Crop Variety Evaluation Programmes, Brian R. Cullis, A B. Smith, C Hunt, Arthur R. Gilmour
An Examination Of The Efficiency Of Australian Crop Variety Evaluation Programmes, Brian R. Cullis, A B. Smith, C Hunt, Arthur R. Gilmour
Professor Brian Cullis
In this paper we present the analysis of yield data from a broad cross-section of crop variety evaluation programmes (CVEP) conducted in Australia. The main sources of variety by environment interaction are ` non-static ' interactions, namely those linked to seasonal influences. These contributed an average of 41.3% of the total variance. In contrast the static component accounts for only 5.3% of the total. We develop methods for determining the relative accuracy of CVEP based on selection of newly promoted entries. The accuracy of the current testing regimes for the Australian CVEP under study is determined. The accuracy of alternative …
A Comparison Of Analysis Methods For Late-Stage Variety Evaluation Trials, Sue Welham, Beverley Gogel, Alison Smith, Robin Thompson, Brian Cullis
A Comparison Of Analysis Methods For Late-Stage Variety Evaluation Trials, Sue Welham, Beverley Gogel, Alison Smith, Robin Thompson, Brian Cullis
Professor Brian Cullis
The statistical analysis of late-stage variety evaluation trials using a mixed model is described, with one- or two-stage approaches to the analysis. Two sets of trials, from Australia and the UK, were used to provide realistic scenarios for a simulation study to evaluate the different methods of analysis. This study showed that a one-stage approach gave the most accurate predictions of variety performance overall or within each environment, across a range of models, as measured by mean squared error of prediction or realized genetic gain. A weighted two-stage approach performed adequately for variety predictions both overall and within environments, but …
Application Of Multi-Phase Experiments In Plant Pathology To Identify Genetic Resistance To Diaporthe Toxica In Lupinus Albus, R. B. Cowley, G. J. Ash, J. D. I. Harper, Alison Smith, Brian Cullis, D. J. Luckett
Application Of Multi-Phase Experiments In Plant Pathology To Identify Genetic Resistance To Diaporthe Toxica In Lupinus Albus, R. B. Cowley, G. J. Ash, J. D. I. Harper, Alison Smith, Brian Cullis, D. J. Luckett
Professor Brian Cullis
Phenotyping assays in plant pathology using detached plant parts are multi-phase experimental processes. Such assays involve growing plants in field or controlled-environment trials (Phase 1) and then subjecting a sample removed from each plant to disease assessment, usually under laboratory conditions (Phase 2). Each phase may be subject to nongenetic sources of variation. To be able to separate these sources of variation in both phases from genetic sources of variation requires a multi-phase experiment with an appropriate experimental design and statistical analysis. To achieve this, a separate randomization is required for each phase, with additional replication in Phase 2. In …
Joint Modeling Of Spatial Variability And Within-Row Interplot Competition To Increase The Efficiency Of Plant Improvement, J. Stringer, Brian Cullis, R Thompson
Joint Modeling Of Spatial Variability And Within-Row Interplot Competition To Increase The Efficiency Of Plant Improvement, J. Stringer, Brian Cullis, R Thompson
Professor Brian Cullis
Trials in the early stages of selection are often subject to variation arising from spatial variability and interplot competition, which can seriously bias the assessment of varietal performance and reduce genetic progress. An approach to jointly model both sources of bias is presented. It models genotypic and residual competition and also global and extraneous spatial variation. Variety effects were considered random and residual maximum likelihood was used for parameter estimation. Competition at the residual level was examined using two special simultaneous autoregressive models. An equal-roots second-order autoregressive (EAR(2)) model is proposed for trials where competition is dominant. An equal-roots third-order …
On An Approximate Optimality Criterion For The Design Of Field Experiments Under Spatial Dependence, Dabid Butler, John Eccleston, Brian Cullis
On An Approximate Optimality Criterion For The Design Of Field Experiments Under Spatial Dependence, Dabid Butler, John Eccleston, Brian Cullis
Professor Brian Cullis
The design of large-scale field trials where the residuals are correlated has been of recent interest, in large part because of advances in statistical and computational methods of analysis. The construction of designs for correlated data has typically used A-optimality and is computationally intensive. This involves calculating the inverse of the information matrix for treatments under the supervision of an optimization strategy that explores the design space. We propose an approximation to A-optimality, using nearest-neighbour balance, that is less computationally demanding and can achieve at least 95% efficiency relative to A-optimality in many practical situations.
Post-Release Mortality Of Angled Sand Mullet (Myxus Elongatus: Mugilidae), Matt Broadhurst, Paul Butcher, Brian Cullis
Post-Release Mortality Of Angled Sand Mullet (Myxus Elongatus: Mugilidae), Matt Broadhurst, Paul Butcher, Brian Cullis
Professor Brian Cullis
Grey mullets (Mugilidae) are important to recreational fisheries throughout the developed world. In Australia, several species are angled and then released in large numbers; all with virtually unknown fate. In response to the need for such data to facilitate effective stock management, this study sought to quantify the post-release mortality and key causal factors for sand mullet (Myxus elongatus). A total of 125 fish were conventionally angled, and then released along with 50 controls into floating cages in a south eastern Australian estuary, where they were monitored for four days. Five treatment fish died, providing a non-significant mortality of 4%. …
The Design And Analysis Of Multi-Phase Plant Breeding Experiments, A B. Smith, P Lim, Brian R. Cullis
The Design And Analysis Of Multi-Phase Plant Breeding Experiments, A B. Smith, P Lim, Brian R. Cullis
Professor Brian Cullis
Despite the importance of selection for quality characteristics in plant improvement programmes, literature on experimental design and statistical analysis for these traits is scarce. Most quality traits are obtained from multi-phase experiments in which plant varieties are first grown in a field trial then further processed in the laboratory. In the present paper a general mixed model approach for the analysis of multi-phase data is described, with particular emphasis on quality trait data that are often highly unbalanced and involve substantial sources of non-genetic variation and correlation. Also detailed is a new approach for experimental design that employs partial replication …
The Analysis Of Qtl By Simultaneous Use Of The Full Linkage Map, A. Verbyla, Brian Cullis, R Thompson
The Analysis Of Qtl By Simultaneous Use Of The Full Linkage Map, A. Verbyla, Brian Cullis, R Thompson
Professor Brian Cullis
An extension of interval mapping is presented that incorporates all intervals on the linkage map simultaneously. The approach uses a working model in which the sizes of putative QTL for all intervals across the genome are random effects. An outlier detection method is used to screen for possible QTL. Selected QTL are subsequently fitted as fixed effects. This screening and selection approach is repeated until the variance component for QTL sizes is not statistically significant. A comprehensive simulation study is conducted in which map uncertainty is included. The proposed method is shown to be superior to composite interval mapping in …
Analysis Of Yield And Oil From A Series Of Canola Breeding Trials. Part I. Fitting Factor Analytic Mixed Models With Pedigree Information, C Beeck, W Cowling, A Smith, Brian Cullis
Analysis Of Yield And Oil From A Series Of Canola Breeding Trials. Part I. Fitting Factor Analytic Mixed Models With Pedigree Information, C Beeck, W Cowling, A Smith, Brian Cullis
Professor Brian Cullis
In this paper multiplicative mixed models have been used for the analysis of multi-environment trial (MET) data for canola oil and grain yield. Information on pedigrees has been included to allow for the modelling of additive and nonadditive genetic effects. The MET data set included a total of 19 trials (synonymous with sites or environments), which were sown across southern Australia in 2007 and 2008. Each trial was designed as a p-rep design using DiGGeR with the default prespecified spatial model. Lines in their first year of testing were unreplicated, whereas there were two or three replications of advanced …
Using A Multi-Experimental Approach To Assess The Fate Of Angled-And-Released Yellowtail Kingfish (Seriola Lalandi), Lachlan W. Roberts, Paul A. Butcher, Matt K. Broadhurst, Brian R. Cullis
Using A Multi-Experimental Approach To Assess The Fate Of Angled-And-Released Yellowtail Kingfish (Seriola Lalandi), Lachlan W. Roberts, Paul A. Butcher, Matt K. Broadhurst, Brian R. Cullis
Professor Brian Cullis
Yellowtail kingfish (Seriola lalandi) are angled throughout their global distribution and released in large numbers under the unsubstantiatedassumption of few impacts. The validity of this supposition was tested for southeastern Australian stocks. In all, 54 fishwere angled and released into cages with 36 controls and monitored for 5 d. Of the angled fish, 15% died, mostly as a consequenceof gill-hooking and the associated physiological and mechanical damage. A biotelemetry experiment was then performed to determineif cutting the line on gill-hooked fish could improve their post-release fate. The attachment of transmitters was validated in anaquarium experiment before 12 jaw- and 10 …
Scale Loss And Mortality In Angled-And-Released Eastern Sea Garfish (Hyporhamphus Australis), Paul A. Butcher, Matt K. Broadhurst, Karina C. Hall, Brian R. Cullis, Robert G. Nicoll
Scale Loss And Mortality In Angled-And-Released Eastern Sea Garfish (Hyporhamphus Australis), Paul A. Butcher, Matt K. Broadhurst, Karina C. Hall, Brian R. Cullis, Robert G. Nicoll
Professor Brian Cullis
The eastern sea garfish (Hyporhamphus australis) is an endemic Australian marine teleost that is angled in large numbers throughout its distribution. Most fish are retained, although some are released, mainly because of size-grading in response to bag limits. Owing to their fragility, there are concerns that few released fish survive. To investigate this assumption, 185 angled and 90 control eastern sea garfish were released in groups of five into holding cages, then monitored for up to 24 h. One control and 93 angled fish died, providing an adjusted angled mortality rate of 49.2%. All fish that ingested their hooks (n¼7) …
Resilience Of Inshore, Juvenile Snapper Pagrus Auratus To Angling And Release, Matt Broadhurst, Paul Butcher, Karina Hall, Brian Cullis, Shane Mcgrath
Resilience Of Inshore, Juvenile Snapper Pagrus Auratus To Angling And Release, Matt Broadhurst, Paul Butcher, Karina Hall, Brian Cullis, Shane Mcgrath
Professor Brian Cullis
This study assessed the mortality of 157 snapper Pagrus auratus (9–29 cm, total length, LT) after being conventionally angled and then released into cages (along with 48 controls) for 4 days off south-eastern Australia. Fatalities were restricted to 12 angled fish (7·6%) and mostly attributed to the ingestion of hooks and especially their subsequent removal, which caused substantial blood loss and immediate death. Hook ingestion was significantly biased towards smaller fish (LT) and attributed to a lower chance of anglers initially detecting these individuals on the line (allowing them to consume more of the baits). While mortalities might be reduced …