We need to get smarter

We as recreational anglers must be very careful at the message we portray, more so now than ever before. Our current government along with our so called environmental groups has been for some years portraying fishing as the single biggest threat to our marine environment, this has a far greater impact then locking us out of areas for no good reason.

What it does, is influence the general community that fishing is a threat, which in Australia’s world class managed fisheries is simply not the case. This is a very real threat to our children and all future generations being able to enjoy what we all enjoy today, not only with the threat of being locked out of increasingly more areas but the very health of our wonderful marine environment is at threat. while everyone is misled to believe that if you remove fishing all will be well, the real threats to our marine environment will not be addressed.

Reducing bag limits will do no more then give us a little more time to address the real issues responsible for a decline in any species. If we don’t address these threats then the writing is on the wall and it’s just a matter of time before some of these species are lost, and when this does occur, it will be us, the anglers that will be held responsible.

NSW DPI is currently conducting a review on the recreational bag limits, that if passed will see a 50% cut in bag limits across the board, on nothing more than social concern. As responsible recreational anglers no one would have a problem with a reduction on bag limits that is shown by good science that it is necessary, and that the bag reduction will address the concerns. But to face a 50% reduction on bag limits on nothing more than social concerns sets a precedent that there will be no turning back from. You don’t have to be Einstein to work out if this anti-fishing campaign is allowed to continue and we allow our regulations to be dictated by how good someone feels, where this will end!

I encourage every angler regardless of where you live to make a submission to this NSW recreational fishing regulations review, with a very clear and simple response, “we will not accept any changes to our regulations that are not based on good science.” No need to say anything more. They can take their social concern and shove it, as far as I am concerned.



This submission is due before the 31^st July.

Discussion paper
http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0005/464765/review_discussion_paper_web.pdf

Submission
http://www.dpi.nsw.gov.au/fisheries/recreational/info/review




We need to turn this tide, today far too much money is being spent trying to justify locking anglers out, and far too little on addressing the real issues, we as angler need to unite and become proactive instead of constantly being reactive. We need to show these so called environmental groups how to do real conservation, not this lolly pop shit they are doing.

We need to unite and join forces with all effected stake holders including the commercial fishing industry, Today it’s not just the general community that has been brain washed by this green filth but anglers are starting to believe the  propaganda as well. This NSW review of fishing rules came about simply because anglers asked for it in the recent survey, we should not be so  willing to place unnecessary restrictions on our selves, I am sure others will be willing to do that for us.

Anglers need to be educated on what the real threats to our marine environment and our species are, we need to put an end to this anti-fishing propaganda, and start making positive changes.

If a group is asking a for our RFL funds to be used to do a study on the impact of commercial fishing it’s not going to happen as recreational money cannot be used for this purpose. But what will happen is a general study in this area on the impact of all fishing, if this group has just spent the last 6 months telling anyone that will listen that commercial fishing is a problem. What will happen once this study finds that recreational fishing in this area has a larger impact then commercial fishing, where do you go from there. Will this group accept the responsibility for the ramifications of such actions?

Just a few years ago the VNPA made an attempt to introduce 20 new marine parks in Victoria, some of these marine parks would have been placed in Corio Bay. Some might say that they don’t recognise the VNPA as a peak or government body, but that didn’t stop them being the main reason we had the marine parks introduced in Victoria in 2002. Shortly after that fisheries attempted to introduce the future fisheries strategy for reform, which would have seen all species target by anglers be placed on a tradable quota, meaning we as a group can only take x amount of fish and if we went over that, we would be forced to make changes.

There are two types of fishery management, input controls (gear controls, trip limits and so one) and output controls (quotas) currently recreational fishing is controlled by input controls The move with the future fisheries strategy for reform was to change our management regime to output controls, if we have a group arguing that input controls are not good enough for the commercial sector how do we justify saying that we don’t want to move to output controls ourselves.
If we claim that 1000 dead fish is a threat to the sustainability of a species in a particular area how do we justify fishing this area ourselves.

With today’s social media it’s easy for a fringe group to push and promote a cause, I am sure they think is justified, it’s up to the fishing media to understand, promote the real information and make their audience aware of the ramifications of such actions, and not give in to what they believe to be and overwhelming public support of a particular issue.

For far too long the conversation has been all about dividing this pie at the end of the food chain, and sharing it with the other stakeholders. If we do a good job of promoting fishing and protecting our rights, we expect to see the amount of people that fish in the future increasing. What we should be talking about is working out what we envisage we will need in the future and start making the changes to ensure that there are plenty of fish for everyone in the future.

By far the greatest threat to not only our targeted species but most marine species is coastal development, modifying the way the runoff water enters our bay, and vital breeding and nursery areas being destroyed or modified by developers. We have seen a huge amount of vital areas like Sea grass, Mangroves Mussel and Oster beds disappear from our coastal marine environment, these areas are vital for a healthy marine population.  I hope the summary below provides some of the answers of what the current conversation should be all about.

This is a summary by Daniel Stanilovic on the presentation from Dr Paul Hamer (Scientist) and Dr Corey Green (Fisheries Scientist) of the Department of Environment and Primary Industries- Fisheries management and science branch, to the VRFish state council Marine policy development workshop on the 23^rd March 2013, it highlights what we should be concerned about and were we need to spend the money on the science to gain a net benefit.

Brief summary (Daniel Stanilovic)

The 4 targeted species (sand flathead, King George whiting, snapper, calamari) discussed by Dr Paul Hamer and Dr Corey Green, , all have displayed significant fluctuations in production over time, but the dynamics and processes driving these fluctuations differ among the species. It is thought for all 4 species that environmental and or habitat changes play an important role in influencing their variation in production. Several sources of information state that Sand flathead have been noted as being the  most problematic species. It has been observed that before they were at their peak in the 1990’s, this species underwent a larger decline then they are currently experiencing, the reasons for these variations was given as environmental driven or as a consequence of their habitat being modified by man, as opposed to angling pressure. Although in most cases with proper fisheries management we as anglers can assist or at least give these species more time to recover, but unless we do something about the causes, then species could potentially be at serious risk, if these threats are not addressed and are allowed to continue over a longer time frame presenting us with some particular concerns. Snapper which was noted as the most valuable recreational and commercial species in Victoria. The major dynamics of this fishery are also believed to be environmental, specifically the Yarra River. Failure to address these environmental threats could potentially put at risk a $1.2 billion Victorian recreational Snapper industry.

It’s also worth noting that the stock assessments are only done on a few key species important to both recreational and commercial fishers, the overwhelming time series information comes from commercial fishing log data.

Overview (Dr Paul Hamer Summary by Daniel Stanilovic)

Stock assessments public forums provide managers and stake holders with information with the status of the fisheries, used to support management decisions or justify new research. They occur every 3-5 years and due to financial restraints are only done on key species.

Key species for recreational and commercial importance are sand flathead, rock flathead, snapper, KGW, calamari, black bream, garfish.

Pre recruit surveys were they go out and measure the abundance of the juvenile young of the species to give indicators of the replenishing of the species, a key driver of the dynamics of the fishery.

Fisheries have been getting information on total commercial catch since 1911, in 1978 they started getting information of catch rates, total catch gives very little information as there is no information on how many fished for what amount of time, catch rates provide much more valuable information. The information on recreational catch is poor although some good information is starting to flow in on some species from krill and recreational angler diary surveys, with length weight and age composition which can tell us of the status of the fishery, and for key species some catch rates from boat ramp surveys. 

Sand Flathead (Dr Paul Hamer, Summary by Daniel Stanilovic)

The most problematic species with a decline in the species, live to about 23 years of age, maximum size 40-50cm females generally grow larger than the male, they reach maturity in 2-5 years at about 22-25cm, females mature later than the males. Bottom dweller, feeding on small fish, small crabs, crustacean’s and sometimes on anchovies, serial spawners meaning a single fish can spawn multiple times over the year and typically have a protracted spawning season from late spring  to early autumn with the majority happening in the spring/summer period. Larva 9 mm at about 18 days of age.
Stock structure is a little uncertain they believe that PPB is an isolated stock separate from the coastal stock, as they spawn in PPB and the ocean, and due to the growth rate of the two stocks PPB reach a maximum size of about 26-27 cm at 5-6 years compared to coastal fish of 30-40cm, this could be genetic or related to environmental factors.

Trawl survey is very effective at catching sand flathead and has been used to accurately estimate the biomass of sand flathead, over a period of 20 years they went out with a commercial trawler and did a bay wide survey of fish stocks, key data was the ability to measure the biomass of sand flathead not just catch rates, by trawling in all different habitats in the bay, then scale that up to estimate the number of sand flathead in the entire bay, and track them over time. In 1990 they estimated that there was 3000 tons of sand flathead in PPB, over the last decade there has been an 80% decline to when the trawl survey finished in 2011.  Catch rates for both commercial and recreational anglers over this same time support this data.

The decade before the 1990’s peak there was also a decline, which is actually lower then it is now, posing some questions on what the true baseline should be. A sustainable exploitation rate is a key indicator of sustainable fishing, globally is believes to be at no more than 30% of the biomass which is where we are now. This decline in sand flathead is not believed to be due to overfishing however although if we want to get the stock to recover to 1990 levels should we be aiming for lower exploitation rates.  The commonwealth fisheries have a trigger point as a reference, that once reached sees a reduction in the exploitation rate although in Victoria we don’t have a system like that.  Poor recruitment is driving the decline meaning they have had a number of years with poor stock replenishing’s. 

There is a direct correlation between recruitment success and river flow, what we are seeing is when we are getting very high or very low river flows we are getting poor spawning success of sand flathead.

Key threats for this species are continuation of this low recruitment trends, as sand flathead inhabit muddy/sandy bottoms its believed that habitat is not a major factor and although the crown of thorn star fish appeared at the same time as the sand flathead decline, looking at the diet composition and growth rate there is no indication that star fish are responsible for the decline of sand flathead. Other major key threats are the climate conditions and productivity of the plankton of PPB.

us that Stock assessments tell us that numbers have not been going down but and have in fact stabilised, and there are even some indicators that they might be increasing

tells have been going down but stabilised, and there are some indicators that it might be increasing.

Do we reduce fishing pressures, or wait for natural factors to change?

Snapper (Dr Paul Hamer, Summary by Daniel Stanilovic)

We know a lot about the broad stock structure of snapper in Victoria, since late 1940,s there has been about 30,000 snapper tagged, through recapture information we have ascertained that there are three broad stocks, Eastern stock (Wilsons prom to southern Queensland) a coastal spawning stock, the Western stock (Wilsons Prom to Murray river mouth) a bays and gulfs spawning stock, and its believed a sub species around Woodside beach and Corner inlet, and some key differences with the SA stock.

The western snapper stock is arguably the most valuable marine species in Victoria on all indicators, and thus it’s the stock most studied.

Fish migrate out from the bays at 1-4 years old some never leave, uncertainties remain on how many fish leave and how many stay,

Snapper live to about 40 years of age and mature at about 5 years of age. 50% of fish mature at about 40cm. Through sampling of the larva in the last decade, and testing the ear bone (otoliths) for chemical markers can tell different water bodies (acting like a natural tag) as well as sampling estuaries along the coast, has shown overwhelming evidence that the western stock only spawn in PPB and to a much smaller extent in WP, making PPB the key nursery area for the western snapper stock, replenishing the entire western snapper stock. Making it risky but making what we are measuring in PPB is telling us about the entire stock.

Pre recruit survey underpinned by that knowledge, going out every year using a very small trawl net deployed from a 7 meter research vessel, designed to catch small fish targeting young of the year snapper, 3 month old fish spawned in December by March they are 8-9cm growing about 1mm a day. The key sampling areas overlap the key spawning areas. These young snapper like an intermediate sandy bottom habitat, in about 10 to 18 meters.

Over the last 20 years the amount of these young snapper caught in these trawl surveys varies greatly. Some years there is an abundance while other years there has been none. These last few years have had little or no young snapper caught in the trawl survey. We know that there has been big fish around laying plenty of eggs, indicating that the problem is not a shortage of eggs but something else is going on. this is one of the key dynamics driving this fishery. One of the key risks is that we are only just starting to understand what is happening to the spawn and it’s hard to predict. even if we didn’t fish this species the numbers of the adults are going to decline if we have a number of poor years so we must start think about managing these dips and peaks to ensure we keep some adults around. Early indicators are showing that this year is looking pretty good, Frankston is usually a really good barometer of how the spawning success is and the trawl survey of Frankston has seen good numbers of 30mm to 10 cm fish, showing a good size range indicating a spawning has been successful over a broad period, and the fact that every trawl over a broad area had these small snapper in them, is a very good sign.

These pre recruit surveys are matching both recreational and commercial the catch rates of following years as the fish mature. Three or four good spawning years will drive the fishery for ten to fifteen years so we don’t need it every year.

During the PPB dredging process funds were available to look at the larvae ecology what they feed on as well as matching the dynamics of the larva to the dynamics of the juvenile for 7-8 years, and the first few weeks of life have been isolated as the critical period that dictates the good from a bad year, and now they are looking at what is effecting the larva during this critical period of life, new research is being conducted  looking at feeding ecology, behaviour, what they prefer to eat and so one, in the good years they prefer to have a diet dominated by certain types of micro crustacean’s (copepod), which are much more nutritional value than other species, and are easier to catch, years where you don’t get many of these copepods also coincides with a poor survival rate of the snapper larva in the first few weeks of age.

The river flow into PPB is the key indicator of the dynamics of the copepod, the Yarra river has probably the biggest influence on the bay in terms of nutrient input, particularly in the western side. Very high or low water flow from the Yarra coincides with poor recruitment. Work is now being done to looking at the food for the copepods (microscopic algae). When we have unusually high nutrients in the water due to higher river flow a particular species of this microscopic algae flourish and dominate in these conditions,  they produce toxic compounds as a defence mechanism making them unsuitable to eat for the copepods.

Key threats are climate and environmental factors, poor recruitment, variable recruitment, first few weeks of age. 

King George Whiting (Dr Paul Hamer, Summary by Daniel Stanilovic)

KGW larva are not found in PPB. The smallest KGW found in the bay are 18-20mm in size using age dating of the ear bone (otoliths) these fish are 80-100 days old meaning they could be coming from a 100’s of km away. No adult fish are found in the bays either, our bays only contain sub adult juvenile fish with a maximum age of 3-5 years, they enter our bays as juvenile fish stay 3-4 years then move out to sea. In SA KGW live 18-20 years.

Working with an oceanographer knowing that the KGW spawn in May and using their age and the current models in reverse the majority of these fish will be spawning west of Cape Otway, the only known spawning grounds are in SA around Kangaroo Island.

An RFL grant research survey looking for adult KGW in PPB found only one fish out of 1600 that was mature, this fish was 1.8kg and 11 years old, the oldest fish found in Victorian waters, this fish was an anomaly and it’s not sure why it was here.

Currently they are looking to see if the SA spawning areas are in fact the main spawning areas of our fishery

The long term of this fishery is dictated by what happens in Bass Strait not what is happening in our bay, it’s the currents that are delivering these fish from the spawning grounds that drive this fishery and we can see a pattern of a ten year cycle.

The westerly winds have been driving these currents. 3-4 years after we get these winds we see good numbers of KGW, warmer water in Bass Strait caused by the Leeuwin current also increase the growth rate of these young fish giving them a greater percentage of survival.

Sea grass is the key habitat, we have good data of catch rates of KGW from 1911 to 2008, In WP we had a major seagrass die back in 1970 that has never recovered, that saw a major decrease in KGW catches, that wasn’t evident in other bays and inlets they were stable through this time. This die back of the seagrass also affected other species, the seagrass provides the food source for the KGW larva as well as shelter.

Currently pre recruit samples are being used to show trends in numbers, the problem is that these samples are only showing the numbers in the seagrass, if we have less sea grass, there might be more fish in less areas, so we need to scale this data with the seagrass data, after the drought there has been indications of the seagrass increasing,

Key threats are the permanent loss of seagrass due to human impact, climates and the east west currents.

Calamari Squid (Dr Corey Green Summary by Daniel Stanilovic)

There has been a lot of research done on Calamari in other areas but not in Victoria, There has also been a huge increase in Calamari fishing in Victoria, with the big boom they are being specifically targeted not just for bait but also consumed as well as catching and releasing, there’s Japanese coming over doing Calamari talks and charters, and Paul Carter is even running a Calamari competition.

Calamari can grow to 3.5kg with a hood length of 500mm distributed around the southern half of Australia, in Victoria about 70% are caught in PPB followed by WP, they are caught all over the coast but these are our primary Calamari recreational fishing areas.

Calamari are specifically attracted to a certain habitat, they generally like specific seagrasses (amphibolous seagrass) this is where they aggregate. They appear to be totally depended on this habitat right from breeding, spawning and early life cycle right up to adulthood.

They have highly adapted vision to catch prey and avoid predators, wings that can move backward or forwards, a funnel that can be used to propel themselves by squirting water as well as squirting ink as a defensive action.

Calamari reproduction is a fairly complex behaviour, the males have a special tentacle that transfers the sperm packets to the female, the males and females can mate multiple times during the year, with a peak in spring summer time, which is relatively important as we are not relying on one particular spawning time.

The female squid lays her eggs in a strand with 7-10 eggs in a strand and about 600 strands in a mop, a mop might have eggs not only from different females but of different ages. The eggs hatch in 20-40 days influenced by the temperature, a higher temp will see the eggs hatch early but they will be smaller and this has an influence on how big the squid will grow. The squid’s growth is very rapid and the larger they are when they hatch the bigger they will grow.

Calamari only live for 12 months, growth is estimated to be about 7-8% a day calamari with a hood length of 300mm is about 300 days old growing about 1mm a day.

The catch rates of squid from PPB, WP and Corner Inlet are up and down from year to year and even with in the same year but they all show similar trends in catch rates with the same peaks and dips, this is showing that there is some broad environmental influence governing the catch rates of calamari across Victoria, it’s not so much the amount of fishing effort, or the squid that’s being removed out of the population, mainly driven by environmental factors. Our extraction in Victoria is nothing compared to other places in the world, about 4.7 million tons in overseas fisheries and some of the best scientists in the world are saying that it’s not a problem and they are not worried about the fishing pressures, that its environmental driven.

2008 stock assessment, 100,000 Calamari caught recreationally in PPB, and 72 tons commercially, the stock status is classified as undefined, as Calamari only have a life span of 12 months thus there is no relevance from the previous year.

Key threats to Calamari are temperature, salinity, productivity, food availability climate change but its more habitat and the areas they can spawn.

Currently there are project that are looking at what the critical habitat in PPB are that the squid need to flourish, their movements around the bay is being looked at with acoustic tags in PPB, there are 65 acoustic receivers in PPB, looking at calamari move around the bay and the whether the calamari move around the bay and mix or stay in specific areas of the bay.

Habitat enhancement (Dr Paul Hamer Summary by Daniel Stanilovic)

Two major goals with habitat enhancement, one is improving the ecological resistance of your system, providing more habitat means if you have impacts on one habitat that might be recovered by having another habitat that’s not impacted, by having more areas there is less chance that whole system will crash, the other is biodiversity turning a sandy bottom with very little diversity into a structured habitat you might increase the species diversity by 10 to 40 fold depending on the system, and the other one is productivity by increasing areas of habitat you increase the overall abundance of a species in the environment, so by increasing the capacity of the system to support more animals.

That approach can be good when you know the species is limited by the habitat in the area. Rebuilding lost habitat and increasing connectivity you can increase the movement of some species which will increases their resilience.

Creating fishing opportunities where you are moving from a system scale to a more local scale approach, placing habitat that creates a new fishing site by aggregating species that can spread the effort to new areas, enhance fishing opportunities.

Recreational fishing reef work was an election promise from both the Labor and Coalition governments and some money from the RFL fund, 4 sub programs 2 have been rolled out and 2 are yet to come. There is an election commitment to spend $16 million dollars to place 8 more estuary fishing reefs, the first 4 are going to go into the Gippsland areas the next 4 will be in the west again possibly PPB or Corio bay, as well as trailing a larger offshore reef structure, all these are designed to enhance recreational fishing experiences they are a recreational initiative solely.

In terms of reef building in the 60’s and 70’s the way to build an artificial reef was to get a bunch of tires tie them together and throw them in the water. But the idea of placing junk items in the water is no now longer accepted, location and planning is now very important. There is a lot of work being done Asia, Japan in particular has been doing this for hundreds of years, they are very big on modifying and manipulating their environment and getting the most out of it, which is a little different to what we do here, we don’t want to change the environment.

A reef ball is a copy of an old Japanese design now patented in America, a concrete and river stone matrix made in a mould, and its blasted with a hose to wash the concrete away and expose the river stone aggregate, it a very high silica and nature ph. it has holes and is hollow in side. These are easy to place and move around if needed. They come in different sizes from 200kg to 800 kg and about 500cm to 1 meter high.

There are also some local designs that have smaller holes that are more suitable for the food of the species we are trying to attract, There are no options to turn a rock wall into practical habitat for not much more money.

These reefs are now being placed in fairly intricate designs as we have the ability to use GPS to assist in there placement, there are some constraints on were these artificial reefs can be placed, other users and other habitat must be taken into consideration.

They have compared the artificial reefs that have been placed with sandy bottoms and nearby natural reefs, with visual divers, baited video sensors as well as recreational anglers that fished these areas before the reefs placement and after and they have found that after only 12 months the reef peaked out with about 50 species counted, but not as many as with the natural reefs but getting close. In terms of abundance of species there was more fish on the artificial reefs then on the natural reefs.  As the study came to an end they started to see more cunje and shellfish growth. One of the criteria’s to assess the artificial reefs was to monitor them for invasive species, so they are not just used as a breeding ground for them and they found that any invasive species had sporadic incursions and would move off the reefs fairly quickly. Modifications are being done on the next generation of reefs to be more suitable for species like seahorses, octopus anemones crabs and so on.

The next stage in the process is site selection for the Gippsland reefs, those reefs should be going in in the coming year, and then the next will be to start looking at the western Victorian reefs with an aim to get them all in the water by 2014.

Offshore reefs also RLF funded $1.1 million, is only at the early stage in Victoria, we understand that they will not be having a negative impact so DCE and the Commonwealth has to approve these, Fisheries only submit an application.  In the Asian countries they are really big in the big structures a little different to us they are making these for commercial fishing enhancement, they work in communities where they have co-operative management in these areas with their fisheries management, they work together in a strong community structure with strong leadership, the decide to rest areas, put fishing enhancements in and so on in a self-management approach. These guys have created all sorts of offshore reefs with baffles to create up welling’s, towers to hold bait fish and do on. NSW, Queensland and WA are all doing off shore reefs. The Victorian reefs will be going in at between depths of 14 to 30 meters.

The current location they are looking at is between Torque and Point Impossible, in a depth of 20 -30 meter, the area has a sandy bottom, its inside state waters, and is accessible from Ocean Grove, Torque and PPB heads.

Fisheries are also working on a FAD project, so we have an option to place the FADs of these reefs which will not only speed up the approval process but they might work very well together.

Another concept fisheries along with the Albert Park Angling club have been working on is living shelf fish reefs, currently Queenscliff has a shelf fish aquaculture production facility set up by fisheries, which gives us the option on restoring some of these lost shellfish habitats. Historically we know that there were large Mussel and Oyster beds in the bay, so why not restore this.

Shelf fish reefs create fish habitats, food for fish, filter water, this is environment improvement and thus we can bring a whole bunch of stake holders into this besides anglers.

Native Ouster reefs have been degraded all over the world, there has been a loss of 90-100% over the last 100 years, Oysters go back to long way in PPB, some work done on looking sediment cores, when the bay was inundated in its geological history, 6000 years ago, and the Oyster was part of the bays from the very start.

A big impact on these Oyster populations happened when the first settlers arrived, and started fishing the bay and started dredging for Oysters particularly in Corio Bay. When you remove the Oyster you also remove the shell and the shell is the substrate for the next generation of Oysters to settle on. The mussel beds that where off Carrum bite prior to the Scallop dredging saw number of around 80-100 per meter square and are now as low as 5-20 per meter square.

Chesapeake Bay east coast in the USA, 6 times bigger than PPB, lost 99% of its Oyster due to environmental factors disease and overfishing, they have now resorted, 6 billion Oysters, 70 Oyster reefs on 13,000 archers. Oysters a key stone species a mature Oyster can filter 50 gallons of water a day, 1 million Oysters can filter 50 million gallons of water day removing silt sediment and nitrogen as well as creating natural reefs. They did this by starting an Oyster shell recovery program that recycled Oyster shells from restaurants, and then used to grow new Oyster spat, together with a partnership of business and community groups with a divers funding source.

Fisheries is looking at creating a small pilot study PPB to go out and try different ways in reseeding these Oysters, and looking at the response to native an invasive  marine communities to them, as well as the cost and benefits. The production side of things are worked out at the Queenscliff aquaculture facility that can produce a run of a million Oysters for about $30,000, plus the cost of placing the Oysters, other issues are disease and invasive species.

http://wefishaustralia.blogspot.com.au/2013/05/oysters-and-mussels-in-ppb.html