With the growing concerns about the Mulloway fish species, particularly in the Clyde River and the plan to remove river habitat (via the proposed bridge construction) that is acting as artificial reefs the following media release from Minister for Primary Industries, Niall Blair is timely. The Batemans Bay bridge pylons have been in-place for a long time and are very effectively acting as artificial reefs. By the RMS Batemans Bay Bridge replacement Review of environmental factors document the location of the replacement bridge proposal is located in a constrained and sensitive environment. "The Clyde River at this location is part of the Batemans Marine Park and is listed as a nationally important wetland. SEPP 14 wetlands, threatened ecological communities, protected marine vegetation and commercial oyster leases are also located near the proposal area. The proposal would result in the following main environmental impacts. The REF proposal would result in: clearing of up to about 2.05 hectares of native vegetation, of which 0.78 hectares consists of threatened ecological communities listed under the Threatened Species Conservation Act 1995 (TSC Act) and Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) clearing of up to about 0.72 hectares of the Illawarra and south coast lowland forest and woodland critically endangered ecological community, listed under the EPBC Act, which is considered to potentially significantly impact this community. Of the native vegetation proposed to be cleared, around 1.78 hectares is considered to provide foraging habitat for some threatened woodland bird species, as well as the Grey-headed Flyingfox. The loss of this habitat is considered to not be significant for these species as suitable habitat is located in the surrounding areas. About 0.43 hectares of the native vegetation proposed to be cleared comprises mangroves, seagrass and macroalgae that is protected marine vegetation and key fish habitat. Biodiversity offsets would be required for impacts to the Illawarra and south coast lowland forest and woodland in accordance with the Roads and Maritime Guideline for Biodiversity Offsets (2016) and to key fish habitat in accordance with the Department of Primary Industries Policy and guidelines for fish habitat conservation and management (DPI 2013). DPI (Fisheries) Batemans Marine Park in their submission indicated that they were concerned that the box girder design with piers near the foreshore may contribute to sediment accumulation in shallow waters. It is understood that the Marine Park zoning for that part of the river will not permit the provision of any offset artificial reefs as a replacement. The RMS have been advised that there was every likelihood of action being taken as a result of significant community concern about declining Mulloway stocks and any action to protect known Mulloway locations should be encouraged. Today we see a Ministerial media release advising that a recent scientific review of the Mulloway Recovery Plan revealed that Mulloway in NSW are still overfished. In order for stocks to recover, the review recommends that more action needs to be taken.
The media release says "After careful consideration of all options available, the Ministerial commercial and recreational advisory councils proposed the following actions to halt the decline of the species and help the stock recover:
- The removal of the possession limit of 10 Mulloway between 45 and 70 cm that currently applies to Estuary General meshing net fishers. This will mean that a 70 cm Mulloway minimum size limit will apply to all fishers.
- A reduction in the recreational bag limit from two to one.
These changes will come into effect on 1 September 2018 and will be closely monitored by NSW DPI. An advisory campaign will also ensure all fishers are aware of the new rules.
"It is recognised that this has been a tough call to make, but it is necessary to ensure Mulloway stocks grow." the Minister
Both advisory councils will continue to look at other measures, including investigating options where commercially-caught Mulloway can be differentiated to reduce black market opportunities, further monitoring to ensure the effectiveness of these actions, as well as more research on fishing gear technologies to reduce bycatch of Mulloway. Further Reading: In the paper "Foraging intensity of wild mulloway Argyrosomus japonicus decreases with increasing anthropogenic disturbance" by Nicholas L. Payne · Dylan E. van der Meulen · Iain M. Suthers · Charles A. Gray · Matthew D. Taylor the authors identified influence of anthropogenic disturbance on the behaviour of wild animals is increasingly recognised for terrestrial systems. One of their principle study areas was the Clyde River. In the abstract of the paper they write: Data on free-ranging aquatic animals are comparatively scarce, and this represents a problem for estimating the consequences of human disturbance for organism fitness and therefore the functioning of aquatic systems. We used acoustic accelerometer and depth transmitters implanted in wild fish and archi-val stomach content data to test for relationships between the intensity of boating and the activity levels and foraging efficiency of an estuarine predatory fish, the mulloway Argyrosomus japonicus. Increasing boating activity Foraging intensity of wild mulloway (inferred from week-long trends in underwater noise and local maritime records) was associated with a reduction in activity levels and increased depth distributions of mullo-way. Stomach content data from a nearby estuary revealed a far-lower feeding rate and altered diet composition on weekends (when boating activity is greatest) compared to weekdays for this species, and an inferred foraging success rate almost one-third that of weekdays. These data suggest the behaviour and foraging intensity of mulloway is significantly influenced by anthropogenic disturbance. The overall fitness costs of the reduction in foraging success will depend on how readily mulloway can reallocate foraging to less disturbed conditions, and the extent of stress-related responses to disturbance in this species. This study supports earlier predictions that anthropogenic disturbances like noise could have significant impacts on the behaviour and fitness of aquatic animals. In February 2013 Andrew Badullovich wrote an article on Clyde River mulloway Four hours south of Sydney and two hours east of Canberra are the fish-rich waters of Batemans Bay. The Bay has many fishing opportunities but the Clyde River is fast becoming a mulloway mecca.Thanks to the removal of commercial fishing effort, (nets removed in marine park) this rejuvenated fishery improves each season and attracting increasing numbers of anglers in search of mulloway. Most mulloway captures are between the Princes Highway bridge at Batemans Bay and the Kings Highway bridge at Nelligen, roughly 5km upriver. Both bridges are themselves major mulloway magnets. AFTER DARK Darkness can aid mulloway captures but tidal movement is probably more important. But I have a soft spotfor night fishing; it relaxes the mind.I choose to fish around the Princes Highway bridge for a few reasons: the bridge lights aid my vision; the bridge hosts a healthy population of live bait and its pylons create perfect current breaks for feeding mulloway. Live bait can be successful in daylight hours, too. Anchoring and drifting both produce fish.
Above: Andrew Badullovich who writes: "This typical night time Jewie ate a live yellowtail within half an hour of the start of the run-in tide. Freshsquid and cut bait also work around the Batemans Bay bridge."
SOFT OPTION Mulloway, like any other fish, don’t feed all day. Every animal has a time to feed and a time to rest. You’re looking for current breaks, which come in the form of structure visible above the surface or below. Mulloway hold in areas where minimal effort is required to swim and feed. They station at the head of the current break, around the bridge pylons where the biggest and fittest fish ambush their prey as it comes past. The RMS, when calling for submissions from the public over the proposed new Batemans Bay Bridge were advised in August 2017: The main issues of concerns to recreational fishers regarding the construction of the new bridge is the protection of fish habitat to ensure the long term availability of fish stocks. This becomes even more important when in a Marine Park. It is well known to those involved in research and recreational fishing that pylon’s of a bridge crossing a river are significant habitat and shelter to all types of marine life. One of the most important tourist attractors to those visiting the Clyde River is the possibility of catching a Mulloway which can grow to a significant size. Many of these fish are now caught, tagged and released for another day. The Mulloway stocks have been in significant decline and are now under are recovery program with commercial take to be reconsidered. Recreational fishers are contributing toward this research.
