ORCID Profile
0000-0003-0513-2363
Current Organisation
Queensland Department of Agriculture and Fisheries
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Publisher: Canadian Science Publishing
Date: 05-2012
DOI: 10.1139/F2012-023
Abstract: Standardized time series of fishery catch rates require collations of fishing power data on vessel characteristics. Linear mixed models were used to quantify fishing power trends and study the effect of missing data encountered when relying on commercial logbooks. For this, Australian eastern king prawn ( Melicertus plebejus ) harvests were analysed with historical (from vessel surveys) and current (from commercial logbooks) vessel data. Between 1989 and 2010, fishing power increased up to 76%. To date, both forward-filling and, alternatively, omitting records with missing vessel information from commercial logbooks produce broadly similar fishing power increases and standardized catch rates, owing to the strong influence of years with complete vessel data (16 out of 23 years of data). However, if gaps in vessel information had not originated randomly and skippers from the most efficient vessels were the most diligent at filling in logbooks, considerable errors would be introduced. Also, the buffering effect of complete years would be short-lived as years with missing data accumulate. Given ongoing changes in fleet profile with high-catching vessels fishing proportionately more of the fleet’s effort, compliance with logbook completion, or alternatively ongoing vessel gear surveys, is required for generating accurate estimates of fishing power and standardized catch rates.
Publisher: Elsevier BV
Date: 05-1996
Publisher: Elsevier BV
Date: 07-1997
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2013
Publisher: Elsevier BV
Date: 06-2007
Publisher: Springer Science and Business Media LLC
Date: 12-07-2012
Publisher: Oxford University Press (OUP)
Date: 03-02-2014
Abstract: Reduced economic circumstances have moved management goals towards higher profit, rather than maximum sustainable yields in several Australian fisheries. The eastern king prawn is one such fishery, for which we have developed new methodology for stock dynamics, calculation of model-based and data-based reference points and management strategy evaluation. The fishery is notable for the northward movement of prawns in eastern Australian waters, from the State jurisdiction of New South Wales to that of Queensland, as they grow to spawning size, so that vessels fishing in the northern deeper waters harvest more large prawns. Bioeconomic fishing data were standardized for calibrating a length-structured spatial operating model. Model simulations identified that reduced boat numbers and fishing effort could improve profitability while retaining viable fishing in each jurisdiction. Simulations also identified catch rate levels that were effective for monitoring in simple within-year effort-control rules. However, favourable performance of catch rate indicators was achieved only when a meaningful upper limit was placed on total allowed fishing effort. The methods and findings will allow improved measures for monitoring fisheries and inform decision makers on the uncertainty and assumptions affecting economic indicators.
Publisher: Oxford University Press (OUP)
Date: 1988
Publisher: Oxford University Press (OUP)
Date: 1989
Publisher: Elsevier BV
Date: 03-1987
Publisher: Springer Science and Business Media LLC
Date: 03-2006
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/MF99029
Abstract: Modal analysis is applied to historical length–frequency records of the Australian southern bluefin tunafishery, in order to quantify the variation in mean length from year to year. In the South Australian fishery in the first half of March, the mean length has ranged between 54 cm and 64 cm for 1-year-old fish, 73 cm and 85 cm for 2-year-old fish, and 85 cm and 100 cm for 3-year-old fish. The mean lengths of 2-, 3- and 4-year-old fish, and the increment from age 1 to age 3, have increased substantially over the history of the fishery. This increase in growth is probably a response to a decline in the population due to heavy fishing. In many years in the Western Australian fishery, two or more groups of 1-year-old fish were found: the mean lengths of these groups typically differed by 10 cm. Growth rates also varied markedly according to the season of the year.
Publisher: Wiley
Date: 11-10-2016
DOI: 10.1111/JFB.13129
Abstract: Sustainable exploitation of fisheries populations is challenging to achieve when the size of the population prior to exploitation and the actual numbers removed over time and across fishing zones are not clearly known. Quantitative fisheries' modeling is able to address this problem, but accurate and reliable model outcomes depend on high quality input data. Much of this information is obtained through the operation of the fishery under consideration, but while this seems appropriate, biases may occur. For ex le, poorly quantified changes in fishing methods that increase catch rates can erroneously suggest that the overall population size is increasing. Hence, the incorporation of estimates of abundance derived from independent data sources is preferable. We review and evaluate a fisheries-independent method of indexing population size inferring adult abundance from estimates of the genetic effective size of a population (N
Location: Australia
Location: Australia
No related grants have been discovered for George Leigh.