Sand Whiting Sillago ciliata

Jason McGilvray^a and Faith Doyle^b

Table 1: Stock status determination for Sand Whiting

Jurisdiction	Queensland	New South Wales
Stock	Queensland (ECIFFF)	New South Wales (EGF, OHF, OTF-PS)
Stock status

	Sustainable	Sustainable
Indicators	Commercial catch and CPUE, length and age frequencies, mortality rate	Commercial catch and CPUE, length and age frequencies, mortality rate

CPUE = catch per unit effort; ECIFFF = East Coast Inshore Fin Fish Fishery (Queensland); EGF = Estuary General Fishery (New South Wales); OHF = Ocean Haul Fishery (New South Wales); OTF-PS = Ocean Trawl Fishery–Prawn Sector (New South Wales)

Stock Structure

Sand Whiting occur along the east coast of Australia, and are most abundant in southern Queensland and northern New South Wales. Tagging studies have shown movement of adult fish between estuaries, but information on biological stock boundaries remains incomplete. Because the biological stock composition is unknown, no formal assessment of the entire biological stock has been completed. Separate assessments of Sand Whiting have been conducted in Queensland and New South Wales^1-4and stock status of Sand Whiting is reported at the jurisdictional level.

Stock Status

Queensland

In 2013, the commercial catch of Sand Whiting in Queensland was below the mean catch during the period 2000 to 2012 (309 tonnes [t]); the catch in 2013 was 240 t. Nominal catch rate (62 kg/day) in 2013 was higher than in the previous 2 years and was similar to the 2009 nominal catch rate
(65 kg/day)⁵. Fishery-dependent monitoring of Sand Whiting, beginning in 2007, indicates consistent length and age structures⁵. These are good indicators of a stable population with continued recruitment. The data indicate that the biomass of this stock is unlikely to be recruitment overfished.

Nominal effort in the Queensland commercial fishery in 2013 was much lower than in previous years (3922 days in 2013, compared with 4771 days in 2012 and 5400 days in 2009), which has improved the commercial catch rate⁵. Effort in the recreational sector of the fishery has decreased since 2001⁶, and the introduction in 2009 of a possession limit (30 fish) caps harvest to acceptable levels. The current minimum legal size for Sand Whiting in Queensland (23 cm total length [TL]) allows a proportion of mature fish to spawn at least once. Sand Whiting has a high rate of survival when released by recreational anglers, thus reducing discard mortality impacts on the stock⁷. Estimates of mortality for Sand Whiting in Queensland (from catch curves) are high. The rate of fishing mortality is equal to the rate of natural mortality, indicating a fully fished stock; however, these mortality estimates have remained steady since 2007⁵. The current level of fishing pressure is unlikely to cause this stock to become recruitment overfished.

Based on the evidence provided above, Sand Whiting in Queensland is classified as a sustainable stock.

New South Wales

Median commercial catch rates (nominal) of Sand Whiting in New South Wales have been relatively steady for the past 5 years and, for commercial hauling in particular, have been slightly greater than those observed in the previous 5 years⁸. The length composition of landings for this species has also been relatively stable since the late 1960s. Local populations that have been studied predominantly comprised fish aged 2–5 years^3,8. The above evidence indicates that the biomass of this stock is unlikely to be recruitment overfished.

Nominal effort levels in 2013 (number of fisher days) in the Estuary General Fishery (approximately 9793 days, summed across methods), the Ocean Haul Fishery (approximately 292 days) and the Ocean Trawl Fishery–Prawn Sector (approximately 217 days) were among the lowest reported⁸. Partly as a result of the historical low nominal effort, the 61 t catch of Sand Whiting in 2013 was below the long-term average of 145 t. The minimum legal length for both commercial and recreational fishers in New South Wales (27 cm TL) reduces fishing pressure on the spawning stock. Recent estimates of mortality from catch curves indicate that the rate of fishing mortality is less than the rate of natural mortality³. The above evidence indicates that the current level of fishing pressure is unlikely to cause this stock to become recruitment overfished.

Based on the evidence provided above, Sand Whiting in New South Wales is classified as a sustainable stock.

Table 2: Sand Whiting biology^3,9-11

Longevity and maximum size	12 years; 510 mm FL
Maturity (50%)	Males: 170–240 mm FL Females: 190–240 mm FL

FL = fork length; TL = total length

Figure 1: Distribution of reported commercial catch of Sand Whiting in Australian waters, 2013 (calendar year)

Table 3: Main features and statistics for Sand Whiting fisheries in Australia, 2013 (calendar year)

Jurisdiction	Queensland	New South Wales
Fishing methods
Commercial
Gillnet	✓	✓
Seine net	✓	✓
Tunnel net	✓
Prawn trawl		✓
Recreational
Rod and line	✓	✓
Cast net	✓
Crab trap and pot	✓
Indigenous^a,b,
Rod and line		✓
Management methods
Commercial
Limited entry	✓	✓
Size limits	✓	✓
Fishing gear and method restrictions	✓	✓
Spatial closures	✓	✓
Temporal closures	✓	✓
Recreational
Size limits	✓	✓
Bag limits		✓
Possession limits	✓	✓
Fishing gear and method restrictions	✓	✓
Licences		✓
Spatial closures	✓	✓
Indigenous^a–d
Section 37(1)(c1), Aboriginal cultural fishing authority		✓
Bag limits		✓
Active vessels
	185 in ECIFFF	235 in EGF 22 in OHF 12 in OTF-PS
Catch
Commercial	237 t in ECIFFF	53.8 t in EGF 5.1 t in OHF 2.7 t in OTF-PS
Recreational	125 t(2010–11)⁶	394 t(2000–01)¹²
Indigenous	Unknown	Unknown
Markets
Domestic	✓	✓
Export

ECIFFF = East Coast Inshore Fin Fish Fishery (Queensland); EGF = Estuary General Fishery (New South Wales); OHF = Ocean Haul Fishery (New South Wales); OTF-PS = Ocean Trawl Fishery–Prawn Sector (New South Wales)

^aIn Queensland, under the Fisheries Act 1994 (Qld), Indigenous fishers in Queensland are able to use prescribed traditional and noncommercial fishing apparatus in waters open to fishing. Size and possession limits, and seasonal closures do not apply to Indigenous fishers. Further exemptions to fishery regulations may be applied for through permits.

^bIn New South Wales, Indigenous fishers are able to use traditional and noncommercial apparatus to take double the recreational bag limit. Further exemptions to fishery regulations can be obtained through permits.
^c The Aboriginal Fishing Interim Compliance Policy allows an Indigenous fisher in New South Wales to take in excess of a recreational bag limit in certain circumstances—for example, if they are doing so to provide fish to other community members who cannot harvest themselves.
^d The Aboriginal cultural fishing authority is the authority that Indigenous persons can apply to to take catches outside the recreational limits under the New South Wales Fisheries Management Act 1994, section 37(1)(c1) (Aboriginal cultural fishing authority).

Figure 2: Commercial catch of Sand Whiting in Australian waters, 2000 to 2013 (calendar year)

Effects of fishing on the marine environment

In Queensland, coastal river and estuary set gillnets have been shown to have minimal impact on the environment and are quite selective in their harvest¹³. Bycatch is generally low compared with the harvest of the target species¹³. Fishers using tunnel nets operate under industry-developed codes of best practice¹⁴. Marine turtles are released with minimal difficulty, and undersized or unwanted catch is returned to the water alive.
In New South Wales, seining in estuaries can incur large amounts of bycatch of undersized organisms and unwanted species, but the use of appropriately sized mesh can reduce mortalities of these species^15–18. Studies conducted in New South Wales indicate that gillnets used in estuaries can incur substantial bycatches, including the capture of undersized individuals of key species^19–21.
Seabirds and other marine life often become entangled in discarded recreational fishing tackle²². In south-east Queensland, a Fishing Line Recovery Bin program was instigated in 2012 to minimise the occurrence of discarded tackle at popular shore-based fishing locations.

Environmental effects on Sand Whiting

Shallow vegetated marine habitats are important for juvenile Sand Whiting, particularly during recruitment periods^23,24. Physical impacts on coastal marine vegetation, subsurface topography and water quality are likely to be detrimental to the Sand Whiting stock.

^aDepartment of Agriculture, Fisheries and Forestry, Queensland
^b Department of Primary Industries, New South Wales

Year	nsw(t)	qld (t)
2000	134.4866	251.1237
2001	181.1044	328.9713
2002	164.6182	294.8277
2003	144.3103	335.8311
2004	164.0563	393.498
2005	151.8044	358.282
2006	190.6255	293.673
2007	168.5745	286.3263
2008	135.3824	269.556
2009	105.3013	352.14
2010	136.0317	299.1
2011	111.9703	272.15
2012	98.4753	284.88
2013	60.7921	244.99