Age, growth and demographic characteristics of Sillago flindersi exploited in a multi-species trawl fishery

Gray, CA; Barnes, LM; Ochwada-Doyle, FA; van der Meulen, DE; Kendall, BW; Robbins, WD

Age, growth and demographic characteristics of Sillago flindersi exploited in a multi-species trawl fishery

Gray, CA Barnes, LM Ochwada-Doyle, FA van der Meulen, DE Kendall, BW Robbins, WD

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Publication Type:: Journal Article
Citation:: Fisheries Science, 2014, 80 (5), pp. 915 - 924
Issue Date:: 2014-09-12

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Field	Value	Language
dc.contributor.author	Gray, CA	en_US
dc.contributor.author	Barnes, LM	en_US
dc.contributor.author	Ochwada-Doyle, FA	en_US
dc.contributor.author	van der Meulen, DE	en_US
dc.contributor.author	Kendall, BW	en_US
dc.contributor.author	Robbins, WD https://orcid.org/0000-0003-1106-1733	en_US
dc.date.issued	2014-09-12	en_US
dc.identifier.citation	Fisheries Science, 2014, 80 (5), pp. 915 - 924	en_US
dc.identifier.issn	0919-9268	en_US
dc.identifier.uri	http://hdl.handle.net/10453/126416
dc.description.abstract	© 2014, Japanese Society of Fisheries Science. This study investigated variability in the growth, length, and age compositions and the rates of mortality of Flinders’ sillago Sillago flindersi exploited in a demersal trawl fishery in eastern Australia. Sampling was done over 2 years across three depth strata at two locations approximately 400 km apart. Ageing of sectioned sagittal otoliths indicated that the observed maximum age of females was 6 years and that of males 5 years, that growth was variable and that the von Bertalanffy growth parameters significantly differed according to gender and location. Females attained a greater L<inf>∞</inf> than males, but males displayed greater k values. The L<inf>∞</inf> values of both sexes and the mean length-at-age for fish aged 3–5 years were greater at the location of highest latitude. Length and age compositions differed according to depth, with smaller (<15 cm FL) and younger (<2 years) fish generally more predominant in the shallow (<30 m) strata than in the deeper (>31 m) strata. S. flindersi appear to use the shallow strata as a juvenile habitat, moving to deeper waters as they grow. This depth stratification between cohorts may reduce intraspecific competition and could potentially be used as a spatial management tool to reduce any fishing-associated impacts on juveniles. Fish between 1 and 3 years old dominated the age compositions of populations combined across all depths, with estimated total mortality ranging between 2.24 and 2.40. Fishing mortality ranged between 1.54 and 1.70 and was more than twice the derived natural mortality. Exploitation rates were approximately 0.70, indicating that the species was heavily fished.	en_US
dc.relation.ispartof	Fisheries Science	en_US
dc.relation.isbasedon	10.1007/s12562-014-0793-z	en_US
dc.subject.classification	Fisheries	en_US
dc.title	Age, growth and demographic characteristics of Sillago flindersi exploited in a multi-species trawl fishery	en_US
dc.type	Journal Article
utslib.citation.volume	5	en_US
utslib.citation.volume	80	en_US
utslib.for	0704 Fisheries Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	closed_access
pubs.issue	5	en_US
pubs.publication-status	Published	en_US
pubs.volume	80	en_US

Abstract:

© 2014, Japanese Society of Fisheries Science. This study investigated variability in the growth, length, and age compositions and the rates of mortality of Flinders’ sillago Sillago flindersi exploited in a demersal trawl fishery in eastern Australia. Sampling was done over 2 years across three depth strata at two locations approximately 400 km apart. Ageing of sectioned sagittal otoliths indicated that the observed maximum age of females was 6 years and that of males 5 years, that growth was variable and that the von Bertalanffy growth parameters significantly differed according to gender and location. Females attained a greater L∞ than males, but males displayed greater k values. The L∞ values of both sexes and the mean length-at-age for fish aged 3–5 years were greater at the location of highest latitude. Length and age compositions differed according to depth, with smaller (<15 cm FL) and younger (<2 years) fish generally more predominant in the shallow (<30 m) strata than in the deeper (>31 m) strata. S. flindersi appear to use the shallow strata as a juvenile habitat, moving to deeper waters as they grow. This depth stratification between cohorts may reduce intraspecific competition and could potentially be used as a spatial management tool to reduce any fishing-associated impacts on juveniles. Fish between 1 and 3 years old dominated the age compositions of populations combined across all depths, with estimated total mortality ranging between 2.24 and 2.40. Fishing mortality ranged between 1.54 and 1.70 and was more than twice the derived natural mortality. Exploitation rates were approximately 0.70, indicating that the species was heavily fished.

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http://hdl.handle.net/10453/126416