Nursery systems are additional phases in the culture of prawns between larval production at the hatchery and final grow out in the pond. 

Introducing nursery phases to Australian prawn production offers greater control over the crop for longer periods of time. Greater control affords the farmer the ability to manipulate growing environments and to more effectively assess production by way of efficiencies.

Post larval care in nursery tanks or raceways can improve the quality of the stock that is put into the ponds by benefiting from:

• Access to the post larvae (PL) for assessment of health and development
• High quality commercial nursery diets
• Reducing water management costs
• Maintaining optimal water conditions
• Improving biosecurity
• Protecting stock from predation

Growing PL to be bigger and stronger in nursery environments means that the animal gets a head start in the pond. Bigger, stronger PL are more tolerant of the stresses of the pond environment and stocking these improved PL can result in improved pond production.

This report gives an overview of the world’s wild harvest abalone fisheries, how they are managed, and the findings of what stock enhancement has been occurring. The countries explored are Australia, New Zealand, Japan, USA and the Republic of South Africa. Hong Kong and The Peoples Republic of China was also visited to explore the market for abalone and customers’ perceptions of hatchery spawned but wild raised abalone.   

The world’s wild abalone fisheries production is declining while abalone aquaculture production has been increasing. Australia’s wild harvest abalone production remained relatively stable since the commercial dive fishery started in the 1950’s until about 2010. Total allowable commercial catch (TACC), commonly called quotas, were implemented in all harvesting regions by the mid to late 1980’s. Successful abalone recruitment is the key issue for a sustainable fishery. There was a low biomass post the implementation of quotas but now fishing pressure was controlled and reduced. A slow recovery occurred from a low spawning biomass until very good recruitments in the late 1990’s, from 2002 to 2006 there was a large spawning biomass on the reefs, the largest it had been for 15 years; recovery was occurring.

Unfortunately, since 2010, despite the large spawning biomass and controlled fishing pressure, production has decreased at an alarming rate. What is happening to recruitment? Why are the abalone larvae not surviving? How can it be overcome? Something is happening when the abalone are in their early larval and settlement stage, at their most vulnerable stage. Can they be nursed through this stage in a hatchery, reseed them when they are stronger and enhance the reefs and commercial production? These questions were the motivation to visit the world’s wild harvest abalone countries. 

Abalone stock enhancement is in its infancy, except for Japan where 30 plus years of stock enhancement sees 30% of their total annual harvest consisting of seeded abalone that achieves a survival rate of 10-15% of what is released. All other countries have undertaken experiments, some for decades with varying results. Further research particularly around the ecology of release areas and large scale projects are needed to determine and improve success. This will be long-term investment requiring substantial money and resources. It is therefore crucial that there is confidence in government to provide protection to the reseeded abalone from any external factors which may interfere with the abalones’ survival. 

Not all locations will be conducive to successful stock enhancement and keeping the handling of the juvenile abalone to a minimum is important for survival. No release method stands out as the most successful. The ideal release size appears to be about 30 millimetres shell length. This size is the best because of genetic fitness. The juvenile abalone is strong enough to not succumb to the environmental factors inhibiting recruitment in the first place and is small enough not to be too domesticated from being raised in a hatchery. 

Genetic diversity contributes to the genetic fitness and the brood stock parents consisting of tens of males and tens of females should be sourced from the area the juveniles are intended to be released to achieve the greatest survival. The parents should be replaced after each spawning season.  

Stock enhancement, combined with resting areas, will be the best way to rebuild the biomass of abalone on the reefs and therefore commercial production.  Utilising technology in a fully transparent commercial fishery will be the way to monitor and manage harvesting pressure to find optimum efficiency, quality and reef production.

A recommendation from the market is to tell the story of successful stock enhancement whereby the sustainability of abalone stocks is being ensured.

In a world where the general population relies so heavily on smartphones and tablets to perform day to day tasks such as banking or checking the weather, the commercial fishing industry has been stubbornly slow to adopt electronic reporting in their businesses. 

As a consequence, fishing regulators around the world are forcing industry to move toward electronic reporting, often against their will. In many cases, regulators are reverting to tactics such as charging for paper-based submissions in an attempt to force this change. Even this rather blunt approach has failed to meet its objective, with many operators hanging on to paper for as long as they possibly can.

This report explores the reasons behind this reluctance to embrace the move to electronic reporting, noting that the very fishers who are hanging onto their paper, moved as members of the general public to electronic banking and online bookings years ago.

The reasons behind their decision to avoid reporting electronically are many and varied. Ironically, none are linked to the fishers’ belief that there are technical challenges stopping them from making the move, with all those interviewed feeling comfortable that if their banking is secure, their fishing data should be secure at a technical level.

The real insight of this report relates to a perceived risk by the fishers that recording their fine scale data, which is really their intellectual property (IP), is putting their businesses at risk. They are fearful that once data is collected it can be accessed by other stakeholders (principally government agencies) and potentially used against them for things like marine parks or quota reductions.   

This report demonstrates that if industry started collecting its own data, it would be in a stronger position to have meaningful dialogue with those stakeholders who ultimately manage their fisheries. All stakeholders would benefit from the greater transparency that well managed, secure data could provide, starting from the decision to open the fishery by the regulator, through to the person who ultimately consumes the catch. 

Can the fishing industry continue to hide its data because of a perceived risk of the government using it against them? Or, does industry and the fisheries regulator, need to get smarter about how they use data to sustainably manage fisheries into the future.