Environmental and fishing effects on the dynamic of brown tiger prawn (Penaeus esculentus) in Moreton Bay (Australia)

This analysis of the variations of brown tiger prawn (Penaeus esculentus) catch in the Moreton Bay multispecies trawl fishery estimated catchability using a delay difference model. It integrated several factors responsible for variations in catchability: targeting of fishing effort, increasing fishing power and changing availability. An analysis of covariance was used to define fishing events targeted at brown tiger prawns. A general linear model estimated inter-annual variations of fishing power. Temperature induced changes in prawn behaviour played an important role in the dynamic of this fishery. Maximum likelihood estimates of targeted catchability ($3.92 \pm 0.40 \ 10^{-4}$ boat-days$^{-1}$) were twice as large as non-targeted catchability ($1.91 \pm 0.24 \ 10^{-4}$ boat-days$^{-1}$). The causes of recent decline in fishing effort in this fishery were discussed.Comment: revised manuscript following reviewers comments + adding data and code for reader

Stout Whiting Fishery Summary : Commercial Quota Setting for 2017

This fishery assessment report describes the commercial stout whiting fishery operation along Australia’s east coast between Sandy Cape and the Queensland-New South Wales border. The fishery is identified by a T4 symbol. This study follows methods applied in (O'Neill & Leigh, 2016a) and extends the results of that study by using the latest data available up to end of March 2016. The fishery statistics reported herein are for fishing years 1991 to 2016. This study analysed stout whiting catch rates from both Queensland and New South Wales (NSW) for all vessels, areas and fishing gears. The 2016 catch rate index from Queensland and NSW waters was 0.86. This means that the 2016 catch rate index was 86% of the mean standardised catch rate. Results showed that there was a stable trend in catch rates from 2012 to 2016, as in the previous study (O'Neill & Leigh, 2016a), with the 2015 and 2014 catch rates 85% of the mean catch rate. The fish-length frequency and age-length-otolith data were translated using two models which showed: • Where patterns of fish age-abundance were estimated from the fish-length frequency and age-length data, there were slightly decreased estimated measures of fish survival at 38% for 2014, compared to fish survival estimates in 2013 at 40%. The 2014 and 2015 estimated age structure was dominated by 1+ and 2+ old fished, with a slightly higher frequency of age 2 - 3 fish for 2015. • Where only the age-length data were used, estimates showed that from 2011 to 2014 the survival index increased. The estimated survival index increased from 35% in 2013 to 64% in 2014, indicating stronger survival of fish as they recruited and aged. Together the stout whiting catch rate and survival indicators showed the recent fishery harvests were sustainable. Since 1997, T4 management (Stout Whiting Fishery) is centred on annual assessments of total allowable commercial catch (TACC). The TACC is assessed before the start of each fishing year using statistical assessment methodologies, namely evaluation of trends in fish catch rates and catch-at-age frequencies measured against management reference points. The TACC has been under-caught in many years. For setting the 2017 T4 stout whiting TACC, the calculations covered a range of settings to account for the variance in the data and provide options for quota change. The overall (averaged) results suggested: • The procedure where the quota was adjusted based on previous TACC setting in year 2016 gave a recommended TACC for 2017 of between 1100 and 1130 t. • The procedure that focussed directly on optimising the average harvest to match target reference points gave a recommended TACC for 2017 of between 860 and 890 t. Use of these estimates to set TACC will depend on management and industry aims for the fishery

Stock assessment of the Australian east coast tailor (Pomatomus saltatrix) fishery

Tailor is a highly migratory fish with an iconic, mainly beach-based fishery on the Australian east coast. There is a pronounced annual, close-inshore run of large schools of tailor from New South Wales, where the fishery peaks in April–June, to Queensland where the Fraser Island fishery at the northern end of the run peaks in August–September. The commercial sector of the fishery developed over the first half of the 20th century while the recreational beach line sector grew strongly from the late 1940s, facilitated by rapid developments in recreational beach-fishing gear. The recreational sector appeared to have had a pronounced peak in both harvest size and fishing effort in the mid-1990s, after which both the recreational and commercial sectors experienced big falls driven largely by cultural change. Recreational participation rates and fishing effort fell sharply while fishery management implemented measures such as bag limits on the recreational sector and harvest limits and spatial restrictions on the commercial sector. Information on the tailor fishery is relatively rich in fish length-frequency and ageing data, although data quality greatly improved from the mid-1990s with the introduction of scientific sampling methods. Prior to that time there were no reliable fish ageing data and most length-frequency data came from tagging experiments. The eastern Australian stock of tailor mainly consists of young fish with not many surviving beyond four years of age. The oldest fish aged by Fisheries Queensland’s monitoring team were just under seven years of age

Assessment of the barramundi fishery in Queensland, 1989-2007

The barramundi (Lates ca/carifer) is an important target species for commercial, recreational and Indigenous fishers across northern Australia. In Queensland, barramundi stocks from the Gulf of Carpentaria (GoC) and the east coast (EC) are managed separately. Updated assessments of both the Goe and EC stocks are reported here. The assessment used catch and effort information from both commercial (CFISH logbooks) and recreational (RFISH surveys) sources. The data were split into six different strata based on the genetic makeup of the stock, leading to six geographical regions with each having its own aggregated total commercial and recreational catch. The analysis proceeded in two stages. The first stage was a standardisation of the catch rate per unit of effort (CPUE) to obtain an estimate of the relative changes in abundance over time. The second stage was fitting a biomass dynamic model to estimate absolute stock biomass and management parameters such as maximum sustainable yield. The primary conclusion drawn from both the standardisation results and the dynamic modelling results is that the data are of insufficient quality to reliably estimate stock biomass or management parameters. This conclusion is based on a number of factors, including (but not limited to): • large fluctuations in the standardised catch rate, which would be biologically implausible if taken as a reliable index of abundance • an inability to find model parameters that lead to a good fit (unless certain parameters are taken past biologically plausible limits) • large uncertainty in parameters estimated from the surplus production model

Queensland Spanner Crab Fishery: Commercial quota setting for June 2016 – May 2018

The Queensland (QLD) fishery for spanner crabs primarily lands live crab for export overseas, with gross landings valued around A$5 million per year. Quota setting rules are used to assess and adjust total allowable harvest (quota) around an agreed target harvest of 1631 t and capped at a maximum of 2000 t. The quota varies based on catch rate indicators from the commercial fishery and a fishery independent survey. Quota management applies only to ‘Managed Area A’ which includes waters between Rockhampton and the New South Wales (NSW) border. This report has been prepared to inform Fisheries Queensland (Department of Agriculture and Fisheries) and stakeholders of catch trends and the estimated quota of spanner crabs in Managed Area A for the forthcoming annual quota periods (1 June 2016–31 May 2018). The quota calculations followed the methodology developed by the crab fishery Scientific Advisory Group (SAG) between November 2007 and March 2008. The QLD total reported spanner crab harvest was 1170 t for the 2015 calendar year. In 2015, a total of 55 vessels were active in the QLD fishery, down from 262 vessels at the fishery’s peak activity in 1994. Recent spanner crab harvests from NSW waters average about 125 t per year, but fell to 80 t in 2014–2015. The spanner crab Managed Area A commercial standardised catch rate averaged 0.818 kg per net-lift in 2015, 22.5% below the target level of 1.043. Compared to 2014, mean catch rates in 2015 were marginally improved south of Fraser Island. The NSW–QLD survey catch rate in 2015 was 20.541 crabs per ground-line, 33% above the target level of 13.972. This represented an increase in survey catch rates of about four crabs per groundline, compared to the 2014 survey. The QLD spanner crab total allowable harvest (quota) was set at 1923 t in the 2012-13 and 2013-14 fishing years, 1777 t in 2014-15 and 1631 t in 2015-16. The results from the current analysis rules indicate that the quota for the next two fishing years be retained at the base quota of 1631 t

Stock assessment of Australian east coast Spanish mackerel (Scomberomorus commerson)

Spanish mackerel, Scomberomorus commerson, are large offshore pelagic fish. On the east coast of Australia, Spanish mackerel form a single genetic stock between Cape York Peninsula in north Queensland and Newcastle on the New South Wales mid-coast. This stock assessment used an annual time-step, two-sex, age-structured population model. The model incorporated data from 1911 to 2020, including estimated commercial, charter and recreational harvest for Queensland and New South Wales, Queensland commercial standardised catch rates, fish age-length frequencies, and key long-term fishery information on fishing power changes and catch rates. Eight model scenarios were run, covering a range of modelling assumptions and fixed parameters. The stock assessment estimates the spawning biomass of east coast Spanish mackerel in 2020 was between 14 and 27% of unfished levels in 1911. The base case model estimate was most likely at 17% of unfished biomass in 2019–2020. This report provides estimates of sustainable harvests for all sectors—commercial, charter and recreational across Queensland and New South Wales—and supports the harvest strategy defined in the Queensland’s Sustainable Fisheries Strategy 2017–2027 (Department of Agriculture and Fisheries 2017)

Queensland Spanner Crab Fishery : Commercial quota setting for June 2015 – May 2016

The Australian fishery for spanner crabs is the largest in the world, with the larger Queensland (QLD) sector’s landings primarily exported live overseas and GVP valued ~A$5 million per year. Spanner crabs are unique in that they may live up to 15 years, significantly more than blue swimmer crabs (Portunus armatus) and mud crabs (Scylla serrata), the two other important crab species caught in Queensland. Spanner crabs are caught using a flat net called a dilly, on which the crabs becoming entangled via the swimming legs. Quota setting rules are used to assess and adjust total allowable harvest (quota) around an agreed target harvest of 1631 t and capped at a maximum of 2000 t. The quota varies based on catch rate indicators from the commercial fishery and a fishery-independent survey from the previous two years, compared to target reference points. Quota management applies only to ‘Managed Area A’ which includes waters between Rockhampton and the New South Wales (NSW) border. This report has been prepared to inform Fisheries Queensland (Department of Agriculture and Fisheries) and stakeholders of catch trends and the estimated quota of spanner crabs in Managed Area A for the forthcoming quota period (1 June 2015–31 May 2016). The quota calculations followed the methodology developed by the crab fishery Scientific Advisory Group (SAG) between November 2007 and March 2008. The total reported spanner crab harvest was 917 t for the 2014 calendar year, almost all of which was taken from Managed Area A. In 2014, a total of 59 vessels were active in the QLD fishery, the lowest number since the peak in 1994 of 262 vessels. Recent spanner crab harvests from NSW waters have been about 125 t per year. The spanner crab Managed Area A commercial standardised catch rate averaged 0.739 kg per net-lift in 2014, 24% below the target level of 1.043. Mean catch rates declined in the commercial fishery in 2014, although the magnitude of the decreases was highest in the area north of Fraser Island. The NSW–QLD survey catch rate in 2014 was 16.849 crabs per ground-line, 22% above the target level of 13.972. This represented a decrease in survey catch rates of 0.366 crabs per ground-line, compared to the 2013 survey. The Queensland spanner crab total allowable harvest (quota) was set at 1923 t in 2012 and 2013. In 2014, the quota was calculated at the base level of 1631 t. However, given that the 2012 fisheryindependent survey was not undertaken for financial reasons, stakeholders proposed that the total allowable commercial catch (TACC) be decreased to 1777 t; a level that was halfway between the 2012/13 quota of 1923 t and the recommended base quota of 1631 t. The results from the current analysis indicate that the quota for the 2015-2016 financial year be decreased from 1777 t to the base quota of 1631 t

Queensland Spanner Crab Fishery: Commercial quota setting for June 2016 – May 2018

The Queensland (QLD) fishery for spanner crabs primarily lands live crab for export overseas, with gross landings valued around A$5 million per year. Quota setting rules are used to assess and adjust total allowable harvest (quota) around an agreed target harvest of 1631 t and capped at a maximum of 2000 t. The quota varies based on catch rate indicators from the commercial fishery and a fishery independent survey. Quota management applies only to ‘Managed Area A’ which includes waters between Rockhampton and the New South Wales (NSW) border. This report has been prepared to inform Fisheries Queensland (Department of Agriculture and Fisheries) and stakeholders of catch trends and the estimated quota of spanner crabs in Managed Area A for the forthcoming annual quota periods (1 June 2016–31 May 2018). The quota calculations followed the methodology developed by the crab fishery Scientific Advisory Group (SAG) between November 2007 and March 2008. The QLD total reported spanner crab harvest was 1170 t for the 2015 calendar year. In 2015, a total of 55 vessels were active in the QLD fishery, down from 262 vessels at the fishery’s peak activity in 1994. Recent spanner crab harvests from NSW waters average about 125 t per year, but fell to 80 t in 2014–2015. The spanner crab Managed Area A commercial standardised catch rate averaged 0.818 kg per net-lift in 2015, 22.5% below the target level of 1.043. Compared to 2014, mean catch rates in 2015 were marginally improved south of Fraser Island. The NSW–QLD survey catch rate in 2015 was 20.541 crabs per ground-line, 33% above the target level of 13.972. This represented an increase in survey catch rates of about four crabs per groundline, compared to the 2014 survey. The QLD spanner crab total allowable harvest (quota) was set at 1923 t in the 2012-13 and 2013-14 fishing years, 1777 t in 2014-15 and 1631 t in 2015-16. The results from the current analysis rules indicate that the quota for the next two fishing years be retained at the base quota of 1631 t