Recreational crabbers in the Peel-Harvey Estuary primarily use nets to catch blue swimmer crabs. The fishery was certified by the Marine Stewardship Council (MSC) in 2016, and the assessment was based on information presented in Johnston et al. http://www.fish.wa.gov.au/Documents/wamsc_reports/wamsc_report_no_3.pdf. This report is the second addition to Johnston et al. 2015) and provides catch and effort information for the 2016 Peel-Harvey Estuary fishing season.
It also provides updates on the progress made to date to meet MSC conditions for fisheries for those criteria where the standard was not fully achieved.
Current Stock Status
Time series of annual standardized commercial catch rate (kg/100 m net hour) of sea mullet in the Peel-Harvey Estuary net fishery, based on original catch rate standardization, relative to the original target (green area), threshold (orange line) and limit (red line ) reference levels outlined in the Finfish resources of the Peel-Harvey Estuary Harvest Strategy, see Table 1.1). Annual commercial catch (tonnes) of mullet in the Peel-Harvey Estuary haul and gillnet fishery relative to the associated harvest strategy reference points. Annual nominal commercial net effort (trawl and net days) in the Peel-Harvey Estuary fishery between 2000 and 2016.
5 Although the increasing trends in both catch rates and catches of sea voles indicate that the stock level is currently sufficient, the recent breaches of the upper threshold levels have prompted a review of the risk to the sustainability of the stock. The outputs of this assessment will be used to inform sustainable harvest levels of this species for the next version of the harvest strategy.
Blue Swimmer Crab
The reference period from 2000/01 to 2011/12 is defined as the period when the fishery operated exclusively with traps and during which the fishery operated normally after the transition from gillnets in the late 1990s. Patterns of water temperature and rainfall in the Peel-Harvey Estuary in 2016/17 versus long-term average trends. The large proportion of sublegal crabs in the Peel-Harvey Estuary is also apparent from the trawl surveys conducted in 2017 (Figure 1.9).
Monthly length frequencies of commercial catches of male (blue), female (red) and juvenile (yellow) blue swimming crabs in the Peel-Harvey Estuary during the 2016/17 fishing season (1 November - 31 August). Monthly length frequencies of fishery-independent trap catches of male (blue), female (red) and blue berry (yellow) swimming crabs in the Peel-Harvey Estuary between June and November 2017. Monthly frequencies of the monthly length of independent fishing catches of male (blue), female (red) and juvenile (yellow) blue swimmer crabs in the Peel-Harvey Estuary in 2017.
Based on the relationship between this index and the commercial catches in the subsequent fishing season, the predicted catch for 2016/17 was 58 t (Figure 1.10), which is very similar to the actual recorded catch of 55 t.
Other Retained Species
Commercial Net Fishery
After above-average catches of yellowfin mullet were observed in the Peel-Harvey Estuary in 2014 and 2015, the catch strategy triggered a Tier 3 (catch curve and recruitment) assessment of the yellowfin mullet stock. 14 The results of the assessment of yellowfin whiting were presented in a 2017 supplement to the study by Johnston et al. Following a peak in the Peel-Harvey estuary tailor catch in 2013, which corresponded to a period of strong recruitment, the annual catch returned to a low level of 1.3 t in 2016 (Table 2.1).
Commercial catch rates of butterflyfish in the Peel-Harvey Estuary varied widely in response to catches over time, with both indicators remaining at low levels between 2013 and 2015. As data for 2017 indicate that this trend has continued above the threshold level, a review will be triggered by the harvest strategy to assess the risk of current catch levels to the overall sustainability of the stock. 3 See http://www.fish.wa.gov.au/About-Us/News/Pages/Yellowfin-whiting-population-in-the-black.aspx, http://www.fish.wa.gov. au/Documents/other/yellowfin_info_sheet.pdf.
Annual commercial catch (tons) of Perth herring in the Peel-Harvey Estuary trawl and gillnet fishery against reference points of the associated harvesting strategy. The combined annual commercial catch of all other species held in the Peel-Harvey Estuary net fishery has remained low at approximately 2% of the total catch in the fishery, which is well below the 5% catch threshold. The only other species retained in commercial trap fisheries for blue swimmer crabs is octopus, with a catch of 32 kg reported for the 2016/17 fishing season.
As in recent years, commercial monitoring of blue swimmer crab trap fisheries shows no change in bait use, typically using about 300g of locally caught mullet and yellow-eyed mullet per trap. Conversion rates (kg bait used per kg blue swimming crab caught) for the 2016/17 fishing seasons have remained the same as the previously reported values in Table 2.2). No further information has been gathered on accidental catches (or baits) in the recreational drop-and-scoop net fishery for blue swimmer crabs since that reported in Johnston et al.
Commercial Net Fishery
Thirty percent of net shots reported had no re-release, compared to 16% of net shots. Less common species in trawl shoots included weeping toadfish (Torquigener pleurogramma) and yellow-eyed mullet (Aldrichetta forsteri). Despite a much lower number of reported gillnets compared to trawls, the data suggest some small differences in the composition and quantity of re-releases between the two capture methods.
The average number of re-released species released from each set of nets was slightly greater than trawl sets (Table 3.1), which is to be expected as nets are typically set overnight and thus remain in the water for longer periods of time. Fishermen reported that the main reasons for not retaining discarded species were not allowed (eg, blue swimmer crabs, rays) due to the catch being below the minimum legal size (eg (eg, weeping toadfish, yellow-eyed mullet) , or of poor quality from predation while in the net.Bycatch starts reported by commercial gillnetters in the Peel-Harvey Estuary from 457 trawls and 25 gillnets between April 2017 and February 2018.
Observation trips were undertaken between April 2017 and February 2018 with seven of the licensees in the Peel-Harvey estuary, with most effort focused on the vessels that operate more frequently throughout the year. Blue swimmer crabs, silver bream, toadfish and yellow-eye mullet were observed in and 17% of the observed net shots, respectively. Bycatch species caught and discarded by commercial net fishermen in the Peel-Harvey Estuary from 27 trawls and two gillnets during observer trips between April 2017 and February 2018.
Monthly monitoring of the commercial traps in the commercial trap fishery in the Peel-Harvey Estuary has shown no apparent change in species composition or the amount of bycatch in the traps. Three species of those discarded from crab traps since the start of the monitoring program in 2007 (Table 3.3), weeping toad, western banded trumpeter and cobbler, have also been recorded as by-catch in net fisheries targeting fin whale species in the estuary. Bycatch species observed in the Peel-Harvey Estuary (commercial trap) fishery for blue swimmer crabs during onboard catch monitoring conducted between 2007 and 2016.
Recreational Drop and Scoop Net Fishery
For example, private property along parts of the foreshore limits direct access to the fishery, and elsewhere 4WD tracks provide seasonal access to the foreshore. Data for the fishing effort at the site is based on 5 randomly selected days for each day type per month of the year for each location between March 2015 and February 2016. Yellow locations indicate locations with potential access issues depending on pitch quality.
As part of the wider study to assess the impacts of recreational netting for blue swimming crabs on habitats in the Peel-Harvey Estuary, an exploration of available shorebird data will be undertaken to identify any areas of particular importance to birds. As counts in most areas are carried out on the same day, the data for each year is considered to provide a reasonable representation of the number of birds present at that time. The total numbers of each of the 85 waterfowl species recorded in the Peel-Yalgorup system since 2008 were surveyed for the first time to get a broad overview of which are most commonly seen in the Peel-Yalgorup wetlands.
Based on the criteria used by the Ramsar Convention when classifying wetlands as internationally important (see Hansen et al. 2016), it is proposed that these surveys be based on 14 migratory and resident waterbird species, of which at least 1% of the population total is supported by the Peel-Yalgorup system (Table 5.3). Approximate location and boundaries of individual count areas in the Peel-Harvey estuary and adjacent lakes within the northern part of the wider Peel-Yalgorup wetland system. The dataset includes counts of more than 430,000 waterfowl in the Peel-Yalgorup system between 2008 and 2017.
Just under a third of the species are classified as migratory shorebirds, while the rest include many shorebirds, ducks, loons, pelicans, cormorants, egrets, herons, gulls and terns. Most of the species recorded in the Peel-Yalgorup system were observed only occasionally, with 68 of the 85 species representing less than 5% of the total number of birds in the data set (Table 5.4). Total counts of major waterfowl species observed in the Peel-Yalgorup system between 2008 and 2017 and their relative contribution to total bird numbers.
For sharp-tailed sandpiper and fairy tern, about 70% of sightings of each species were from the Peel-Harvey Estuary. The latter species is also equally abundant at the mouth of the Harvey River in the southern part of the estuary.
Compliance and Enforcement
A summary of breach data related to compliance efforts in the wider Peel-Harvey estuary area, noting that this also includes ocean waters outside the estuary.