An Investigation into the Commercial Feasibility of Jasus edwardsii Aquaculture in New Zealand
A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Technology Management and Innovation at the University of Waikato by Ian Hector Ruru.
Awarded with First Class Honours, University of Waikato, 2000.
Acknowledgements
Maungahaumi te maunga
Waipaoa te awa
Takitimu te waka
Te Aitanga-a-Mahaki, Ngai Tai, Whakatohea, Ngati Porou nga iwi
Te Whanau-a-Kai te hapu
Rongopai te marae
I wish to thank the following people and organisations for their help and assistance. My two supervisors from the University of Waikato, Bob Mills for direction and thoughtful insight into the process of innovation, and Emeritus Professor Janis Swan, for thorough, timely and encouraging feedback. Gary Bramley for advice on the statistical analyses. Chris Zame, Kim Boyd and Leigh Sullivan from Aqua (Bay of Plenty) Ltd., for sharing their knowledge of the aquaculture and seafood industries. Dr Andrew Jeffs, Dr Simon Hooker and Dr John Booth from NIW A for providing scientific support. The Ruru and Shivnan whanau for their continuing tautoko and aroha. I am grateful to Te Ohu Kaimoana and the Wi Pere Trust for their financial and moral support. I especially acknowledge my partner, Simone Shivnan, who has supported me throughout.
This work is dedicated to our son Riaki Shivnan Ruru.
''Ka pu te ruha
Ka hao te rangatahi"
Abstract
In 1996 New Zealand introduced legislation to allow Jasus edwardsii pueruli to be collected as "seedstock" and ongrown in a commercial aquaculture trial. The aim of this thesis was to investigate the commercial feasibility of J. edwardsii aquaculture in New Zealand by working with an organisation involved in the trial. The methodology involved a combination of experiments In the field, in laboratories, and within an ongrowing facility. This thesis examined five key areas and found the following:
  1. Data obtained in the research indicates that New Zealand will continue to rely on harvesting pueruli from the wild since significant technical obstacles remain in the development of commercial scale pueruli hatcheries. Forecast data, obtained using the delphi technique and information about current research on larval rearing, indicates that commercial scale supply of pueruli from hatcheries may occur between 2017 and 2021.
  1. Harvesting trials collected a low number of pueruli with the lowest unit cost for collection being $1.80. A greater collection rate could be achieved with a better understanding of seasonal and local settlement patterns.
  1. Survival rates in pueruli transporting experiments were significantly affected by stocking density, time and temperature. The safest transit conditions were achieved with 15 pueruli per litre for less than 6 hours at 14°C.
  1. A range of stocking densities, from 3 lobsters per tank to 12 per tank, were tested for their effect on growth of six-month old lobsters. The lobsters were reared in a total recirculation seawater system at a constant 16°C, and fed fresh mussels (Perna canaliculus). For the 121 day trial, no statistically significant effect was detected. However, there was a trend for growth rates to be highest at 3 and 6 lobsters per tank and for growth rates at stocking densities of 9 and 12 lobsters per tank to decrease after Day 50. Lobsters showed increased mortality at the highest stocking rate. 111
  1. A bioeconomic model of a hypothetical farm was developed to assess economic benefits and risks and to determine overall profitability. The model showed an annual net cash position of $287,100 and cumulative cash position of $859,200 by the 10th year of operation based on annual sales of 10,837 kg at $65 per kg. The model indicates that the highest cost components in the first 10 years are processing and transport, and labour. Based on the model and the scenarios examined, profitability is very sensitive to factors such as the farm size, processing and transport costs, and sale price. Biological factors such as growth rates, survival, and feed requirements also influence overall profitability. Good returns will depend upon consistent exports of high quality lobsters.
  1. The study concludes that commercial feasibility will be affected by these key areas. The potential of J. edwardsii aquaculture in New Zealand will continue to benefit from further research.
Background: The New Zealand Rock Lobster Fishery
The New Zealand rock lobster fishery is based mainly on the palinurid lobster Jasus edwardsii (Hutton, 1875), which accounts for more than 99% of the commercial harvest (Booth & Breen, 1994). Commercial fishers use baited pots to catch lobsters, which are then held in land-based holding facilities to be "conditioned" (temperature-induced hibernation) before being exported. The holding period can be varied according to market demand and price. Ninety percent of the lobster catch is processed and airfreighted live to Asian markets.
Total rock lobster exports in 1998 were worth $NZ101.7 million, which was $NZ9.1 million less than exported in 1997 (NZSIC, 1998). This decrease meant that lobster fell from second to third most valuable fishery.
The Quota Management System
New Zealand's commercial fishery is managed under the Quota Management System (QMS), which was introduced in 1986 to manage and conserve the major commercial fisheries (Clement & Associates, 1997). Under the QMS, the right to catch is assigned to individual fishers. The sustainability of the fishery is also protected by restricting the catching of fish below a minimum legal size (MLS). All fish caught below the MLS must be returned to the water or else the fisher risks prosecution.
The rock lobster industry "is very much dependent on productive fish stocks and strong export market returns for its economic prosperity" (Sykes, 1996). Increase in rock lobster production from wild fisheries are unlikely as most fisheries are fully exploited, or over exploited and near their long-term equilibrium (Annala, 1993). The only way to expand production is through enhancement and aquaculture (Kittaka & Booth, 1994).
The Aquaculture Trial
Increasing market demands and diminishing natural populations have generated considerable interest in rock lobster aquaculture (Hooker et al., 1997). The potential benefits of aquaculture are that it is a form of long-term sustainable production, may relieve fishing pressure and can have a relatively low impact on the environment.
In late 1996, New Zealand introduced legislation to allow commercial harvesting and ongrowing of J. edwardsii pueruli under a trial trade-off scheme. Before this trial, pueruli had only been harvested from the wild on a much smaller scale, mainly for research purposes. The trial was a world-first and seen as an opportunity for new business and a mechanism to help develop the New Zealand rock lobster aquaculture industry.
Early Research and Market Potential
Encouraging results from research (Hollings, 1988; Manuel, 1991; Rayns, 1991) had demonstrated that growing juvenile J. edwardsii was possible and that reasonable survival rates could be achieved (Hooker et al., 1997). Market research had identified a lucrative niche export market for 'tailor-made' lobsters (Hollings, 1988; Oshikata, 1994). Two organisations - Aqua (Bay of Plenty) Limited (Aqua BoP) and Hawkes Bay Aquaculture Limited (HB Aquaculture) took up the challenge and invested to pioneer this industry. Developments were assisted by government-funded research completed for the two organisations by the National Institute of Water and Atmospheric Research Limited (NIWA).
Challenge 1: Sourcing Seedstock
Bill Ruru [1941-2016] underneath the Gisborne Wharf sorting pueruli that he could then courier live over to Papamoa.
A fundamental issue limiting aquaculture of J. edwardsii and other spiny lobster species is obtaining enough pueruli as seedstock. The seed source for J. edwardsii pueruli aquaculture can be either harvested from the wild or cultured in hatcheries. Currently, all pueruli supplied to research or commercial organisations are harvested from the wild because cost-effective larval rearing techniques have yet to be perfected.
The ability to produce J. edwardsii pueruli economically will have a significant impact on rock lobster aquaculture and the New Zealand rock lobster fishery. According to Peacey (1997), 'closing the life cycle' of species such as rock lobster, by developing the technology to produce juvenile animals from farmed stock, will make the industry less dependent on natural resources of juveniles and increase the industry's ability to undertake selective breeding. Furthermore, developing a process for culturing rock lobster throughout their life cycle would also reveal the potential for enhancement of the wild stock (Sykes, 1996; Schapp, 1997).
Challenge 2: Harvesting
The viability of the industry depends on "access to predetermined numbers of pueruli irrespective of natural fluctuations" (Thomas et al., 1998). The most prolific and consistent settlement areas of J. edwardsii pueruli are on the East Coast of the North Island, south of East Cape to Castlepoint. New Zealand research programmes have largely relied on a "crevice collector", developed in the 1970s, to collect pueruli. This collector was primarily designed to monitor puerulus settlement patterns along the coastline and has changed little since its invention.
Whilst being suitable for research purposes, it was inevitable that the advent of the aquaculture trial and commercial scale demands for pueruli would require improved and/or new types of harvesting devices. From a commercial perspective, new collectors need to be cost-effective, easy to construct, operate and maintain (Thomas et al., 1998).
Special Permit Regulations
The Special Permit regulations that govern the aquaculture trial, stipulate that only J. edwardsii pueruli and first instar juveniles can be harvested for ongrowing. For the purpose of this thesis, the term 'pueruli' includes all three puerulus stages and first instar juveniles (Stages; P1, P2, P3 & J1).
Challenge 3: Transporting
Aqua BoP harvests over 90% of its pueruli from collectors in the Gisborne Harbour. Once harvested, the pueruli are transported by road to the ongrowing farm in Papamoa 300km away. This journey can take up to nine hours.
For transit the pueruli are packed in plastic bags filled with ambient temperature seawater (between 12-18°C) and placed into insulated containers. Severe deterioration in the transport environment such as increasing ambient temperatures or excessive vibrations can reduce survival rates. Therefore, lobster survival depends on developing safe and reliable handling and transporting protocols.
Challenge 4: Ongrowing
Information on growth and mortality is needed to assess the economic feasibility of J. edwardsii aquaculture (Sorensen, 1969). Previous studies of the growth of captive J. edwardsii (Hollings, 1988; Rayns, 1991; Hooker et al., 1997; James & Tong, 1998) used simple flow-through culture systems. Filtered seawater at ambient temperature was continuously pumped from the adjacent ocean. The seawater flowed once through the ongrowing unit and was then discharged back into the ocean. The captive juveniles had good growth rates and high survival rates.
Aqua BoP uses a prototype recirculating seawater system to grow the juveniles through to a saleable size. In this system, the seawater is recycled continuously through complex filtration units to remove impurities and waste. Fresh seawater is trucked to the facility periodically to replenish the system.
Recirculation vs Flow-Through Systems
In comparison to flow-through systems, recirculation systems have the advantage of having greater control over environmental factors such as weather and location. However, with the exception of Manuel (1991), these systems are largely unproven for lobster ongrowing.
Challenge 5: Bioeconomic Analysis
It is prudent to carry out a bioeconomic analysis of profitability when assessing commercial feasibility of an aquaculture venture. The valuable but dated study by Hollings (1988) concluded that J. edwardsii aquaculture could be profitable. There is very little published information on the economic feasibility of culturing J. edwardsii. However, the economics of aquaculture of other families of lobsters have been assessed (Allen et al., 1984; Nash, 1990; Medley et al., 1994).
Production and market uncertainties significantly affect the viability of an aquaculture facility. Mathematical modelling of production and marketing issues is one way of assessing the economic feasibility of an aquaculture venture (Zucker & Anderson, 1999). The economic climate and uniqueness of each venture means that the analysis must be customised. Such an analysis may also indicate the significance of various parameters such as sensitivities to feed price, survival rate and sale price, on potential profitability. Furthermore, productive research and development areas may be identified from the analysis.
Statement of the Problem
The Ministry of Fisheries (1996) introduced legislation to allow J. edwardsii pueruli to be collected as "seedstock" and ongrown in commercial aquaculture trials.
"It is the Ministry's intention that any special permits issued pursuant to the approved purpose will be for trials to establish the viability and biological neutrality of a system that allows adult rock lobster to be traded off against taking juveniles that have not yet been recruited into the fishery. There is no guarantee of ongoing approvals and any business decisions should be made with this in mind."
A commercially successful process to harvest and ongrow J. edwardsii pueruli has yet to be achieved. The aim of this thesis is to investigate the commercial feasibility of J. edwardsii aquaculture in New Zealand.
Research Approach
The aim was to work symbiotically with a commercial aquaculture company (Aqua BoP) throughout the trial period. In this way the research objectives underpinning the thesis would be guided by first-hand experiences with the commercial realities of the new venture.
The Research Questions
The research wanted to address the following questions:
  1. How might J. edwardsii pueruli be sourced as a seed stock for aquaculture?
  1. Can J. edwardsii pueruli be harvested cost-effectively?
  1. Once harvested, how can J. edwardsii pueruli be transported to the grow-out site safely?
  1. How might stocking densities affect growth rates of juvenile J. edwardsii cultured in a recirculating system?
  1. What are the potential economic benefits and risks of J. edwardsii aquaculture?
Life History and Ecology of J. edwardsii
The spiny or rock lobster (Crustacea: Decapoda: Palinuridae: Jasus) J. edwardsii is found in the shallow (0 to 50m) coastal waters of New Zealand, South Australia and Tasmania. J. edwardsii, like most spiny lobsters, has a long and complex life cycle (Phillips & Sastry, 1980; Booth & Phillips, 1994). Life begins as an externally fertilised egg carried on the ventral surface of the female's tail (MacDiarmid, 1988). The egg is incubated for three to six months depending on the water temperature, and hatches into a small naupliosoma larva. The female moves to an area with strong current action to aid dispersal and releases the larva. The naupliosoma larva soon moults into a leaf-shaped phyllosoma larva.
The Phyllosoma Stage
The phyllosoma drift for hundreds of kilometres, moving up and down the water column to feed. They spend between 12-24 months at sea, passing through 11 planktonic larval stages often moulting several times between each stage. Ocean current carries the late-stage phyllosoma closer to the continental shelf where it metamorphoses into a post-larval puerulus (Booth & Breen, 1994).
The Puerulus Stage
The puerulus resembles the juvenile in shape (9-13 mm CL) but is transparent because the exoskeleton lacks pigment and calcium. It settles in shallow coastal waters often preferring small crevices for shelter. After three stages (P1, P2 and P3) the puerulus moults into the first instar juvenile (J1). The juvenile often remains in shallow inshore nursery areas before moving to deeper water (Cobb & Wang, 1985).
Growth and Maturity
Remaining growth follows an exponential function and is related to temperature (Saila et al., 1979). The growth of J. edwardsii at ambient water temperatures in southern New Zealand (6-17°C) is slow (McKoy, 1985; Rayns, 1991) but increases in warmer ambient water temperatures in north-eastern New Zealand (Hooker et al., 1997). Size and age at maturity is highly dependent on local environmental conditions (Annala et al., 1980). Lobsters in the wild take about of five years to reach the MLS or a weight of approximately 400 g (Tong & James, 1997).
Growth is a discontinuous and stepwise process consisting of a series of moults (ecdyses) separated by moult intervals. The period between successive moults is known as an instar. At each moult the lobster sheds its old shell and emerges in a new soft shell. Like all crustaceans, the lobster depends on a rigid exoskeleton (shell) for structural support and protection. The lobster is very vulnerable to predation until the new shell hardens (Rayns, 1991).
Lobster Morphology
The body can be divided into two parts; the cephalothorax and the abdomen. The cephalothorax consists of the fused head and thorax. The appendages on the cephalothorax include the eyes, the antennae and antennules, the mouth-parts and five pairs of legs. The abdomen (tail) is a muscular structure also covered with a shell. The abdomen shell is divided into six segments to allow flexing or rapid backward swimming. Female and male lobsters are similar in appearance except the female has a pair of pincers on the hindmost pair of walking legs, genital apertures at the base of the third set of legs rather than the hindmost (for males), and extra pleopods on the underside of the tail. The carapace length, which is the distance from the base of the sub-orbital horns to the posterior of the carapace, is frequently used by researchers to indicate body length (Cobb & Wang, 1985).
Challenges in Culturing Phyllosoma
Culturing phyllosoma in a laboratory has been difficult because of the complex life cycle (Phillips & Evans, 1997). Growing a J. edwardsii puerulus from the egg was first achieved in Japan (Kittaka, 1988). New Zealand's first success at complete phyllosoma development occurred in 1995 (Booth, 1996). However, the extremely low survival rates have hindered transferring the laboratory technology to commercial-scale hatcheries that would provide pueruli for lobster farmers. This alternative seed stock would reduce the reliance on harvesting pueruli from the wild. Hatchery-supplied seed stock is common in the aquaculture of other marine and freshwater animals. For example, the New Zealand paua or abalone (Haliotis iris) is farmed for the meat and for mabe (half-round) style pearls. The breeding biology and life cycle of an abalone is well understood and so commercial hatchery operations supply most of the seed abalone used for aquaculture (Tong & Moss, 1992).
Jasus verreauxi: A Promising Alternative
The spiny lobster species Jasus verreauxi (packhorse lobster) has been successfully cultured through to the puerulus stage. This species is uncommon in New Zealand waters, with an annual commercial harvest of about 10 tonnes compared to about 3,000 tonnes of J. edwardsii. J. edwardsii aquaculture has received more research attention because it is perceived to be of higher quality than J. verreauxi, and therefore deemed more lucrative. However, interest in farming J. verreauxi has increased for two reasons. Firstly, it is a warm water species with a fast growth rate; secondly, there has been greater success in rearing the eggs and larvae. This is attributed to this species having a shortened and hardier larval life than J. edwardsii (Tong, 1999). Lessons learned from rearing J. verreauxi may accelerate the development of commercial-scale hatchery production of J. edwardsii.
Monitoring Puerulus Settlement
Puerulus settlement around New Zealand has been monitored since the 1970s to better understand larval recruitment processes and therefore assist in management of the fishery. A knowledge of seasonal, interannual, and geographical variation in settlement has been used to predict recruitment, provide early warning of overfishing, and show levels of interannual recruitment variability (Booth & Stewart, 1993). Similar information has been essential to management of the Western Australian rock lobster fishery (Phillips, 1986). Large numbers of J. edwardsii pueruli are known to settle on the East Coast of the North Island, south of East Cape to Castlepoint, (Booth & Stewart, 1993). Large pueruli settlements have also been recorded in the Marlborough Sounds and in the seawater intake of the New Plymouth power station (Booth, 1989). Settlement does not take place uniformly with time or between geographic regions (Booth, 1991). Settlement is mainly at night and can occur at any lunar phase. It is usually seasonal and levels of settlement can vary by an order of magnitude or more from year to year (Booth, 1999). The crevice collector was developed to monitor puerulus settlement. It consists of seven crevices, each 25 mm at its opening, created by stacking eight plywood sheets, with spacers, in a metal frame.
Stressors During Transport
Pueruli are exposed to several potential stressors when captured and transported. The most significant stressors include harvesting and handling, post-harvest transfers, induction of vigorous escape behaviour (tail flicks), physical damage (e.g. limb loss, blood loss), interactions between pueruli, poor water quality in transporting vessels, and exposing the pueruli to air. Stress responses may be evaluated subjectively (behaviour, vigour) or expressed quantitatively by measured changes in physiological variables such as oxygen uptake, heart rate, muscle metabolites, blood gases, pH, hormones and ions (Taylor et al., (1997)). Lobsters are ectothermic (outside heat) which implies that their metabolic rate increases as the temperature increases. Oxygen is essential for respiration; the amount required increases with stress and temperature. Dissolved oxygen concentration is also influenced by temperature; the higher the temperature the lower its oxygen concentration. Lobsters kept at high densities are especially prone to die if there is a build-up of nitrogenous wastes and decrease in dissolved oxygen (Vijayakumaran & Radhakrishnan, 1997).
Ongrowing Systems: Flow-Through
Flow-through and recirculating systems are used to culture lobster in New Zealand. The flow-through or open system is the simplest type of operation. Seawater is pumped from a nearby harbour or bay and mechanically filtered to remove impurities. For example, NIWA's Mahanga Bay Research Centre uses a triple-unit, multimedia (sand and carbon) filter. The system can remove particles as small as 20 μm and supplies up to 36 m³ of seawater/hour to the research facility. After the filtration process, the seawater passes through the reticulation system to the ongrowing tanks and is then pumped back to sea (Illingworth & McDermott, 1997). The main limiting factor of a flow-through system is having a reliable source of high quality seawater at ambient temperatures that promote rapid growth. These systems are also subject to pathogens and algal toxins that may appear periodically in the ocean environment and adversely affect the lobsters. To adequately manage these risks, early warning bioassays, complex filtration and sterilisation systems and may be necessary (Chang & Redfearn, 1999).
Ongrowing Systems: Recirculating
Recirculating or closed systems are usually more complex than flow-through culture systems. As a result they have higher initial capital costs and relatively high operating costs. The major components of a recirculating system include; ongrowing tanks, mechanical filter, biological filter, heat exchanger, pump and a reservoir. A major concern of a recirculating system is the build-up of metabolites. Mechanical filtration is required to remove solids, uneaten food and faeces. Toxicity of the nitrogenous compounds can also be a serious problem. Sub-lethal ammonia and nitrite levels may reduce growth, damage gills and other organs, and may be a trigger factor for several diseases. The ammonia and nitrite can usually be controlled with a biological filter, which has nitrifying bacteria that metabolise excreted ammonia and convert it to nitrate and nitrite. Lobsters can tolerate higher concentrations of nitrate than ammonia, and the water can be reused almost indefinitely if the nitrification process remains stable (Spotte, 1970). A heat exchanger controls water temperature and a pump and reservoir help control water flow. Two major advantages of a recirculating system are the capability to manage and control optimum culture conditions and the capability to operate in isolation from the external environment. Aqua BoP uses a recirculating system to ongrow pueruli.
Habitat Requirements
The habitat for captive spiny lobsters needs to accommodate their complex social behaviour. Aqua BoP uses shallow (200 mm water depth) rectangular tanks that are stacked three layers high to minimise floor area. Minimising waste material build-up by maintaining good tank hygiene greatly reduces the risk of bacterial contamination. Lobsters are graded so tanks contain similar-sized animals. Large individuals may dominate for shelter and food, reducing growth and increasing cannibalism (Rayns, 1991). Cannibalism is especially common among spiny lobster if there is a shortage of food or shelter. Moulting or just-moulted animals seem to be the most vulnerable, but it is uncertain whether healthy animals are attacked (Booth & Kittaka, 1994; personal observation). Death at moulting has been widely reported among captive spiny lobster, often with symptoms consistent with moult death syndrome (MDS) of homarids or clawed lobsters (Rayns, 1991; Gerring, 1992). Stress and poor nutrition are possible causes of MDS (Conklin et al., 1991).
Temperature Effects
Water temperature affects metabolic rate and thus has a significant effect on respiration, food intake, digestion, assimilation, growth and behaviour (Forteath et al., 1993). Temperature strongly influences the growth of juvenile spiny lobster. The optimum temperature for growth and survival of juveniles is approximately 16-18°C (Hollings, 1988; Forteath et al., 1993). Juvenile lobsters stop growing if the water temperature is below 10°C (Manuel, 1991). Above 23°C mortality increases (Hooker et al., 1997). Accelerated growth decreases production costs because of labour and energy cost savings. However, these gains can be negated by lower food conversion efficiency, higher food consumption, greater activity and increased incidence of disease (Booth & Kittaka, 1994).
Stocking Density
The generally communal nature of spiny lobsters make them especially suitable for culture. Tank stocking rates are generally 100/m² for puerulus to one-year old animals, 50/m² for one to two-year old, and 30/m² for two to three-year old animals (Hooker et al., 1997). However, at excessively high densities, growth and survival can be adversely affected. Higher densities reduced growth rates of juveniles with physical and chemical cues being held responsible. Mortality was also highest under crowded conditions; large individuals survived better than smaller ones in tanks with a size mix and some cannibalism occurred. Lobsters held in tanks downstream of either similar-sized or larger animals grew slowly. This may be due to a growth inhibitor released by the lobsters upstream (Rayns, 1991).
Ablation and Photoperiod
Ablation (surgical removal) of the eyestalks has been used in nutrition research and has the potential for accelerating growth in aquaculture (Rayns, 1991). Eyestalks are the sites for synthesising a moult-inhibiting hormone, and ablated lobsters moult more frequently and grow faster. However, attempts to use this technique on small lobsters usually result in high rates of mortality, especially during moulting. Marketing and ethical concerns also limit widespread use of this practice (Berry, 1997).
Brett (1989) found that growth of juveniles in the laboratory was influenced by photoperiod (rate of dark and light periods) manipulation. Berry (1997) identified maximum growth occurred with LD16:8 (16 hours light : 8 hours darkness) light regimes. The light cycle may be varied to modify behaviour and promote feeding and growth.
Diet and Nutrition
Lobster feed contributes to a large percentage of the production costs. The food must have high nutritional value, be acceptable to the lobsters, available all year round at reasonable cost, and be easy to store and handle. Artificial diets consist of dry or moist pellets made from powdered, mixed feed ingredients. A binding ingredient such as wheat gluten or alginate is included so that the pellet will have high stability in water. Binders also reduce the rate at which water-soluble nutrients such as vitamins leach from the feed. Gerring (1992) reported that juvenile lobsters grew slowly and survived poorly on some artificial diets, including some commercially available for crustacea; moult death syndrome appeared to be a common cause of death. The lack of suitable artificial food ration is a major obstacle to commercial lobster farming.
Captive lobsters prefer foods of a marine rather than terrestrial origin (Fielder, 1965). Daily feeds of fresh rather than frozen Mytilus galloprovincialis (blue mussel) and Perna canaliculus (Greenshell mussel) have consistently produced the best growth rates. Diet also affects the degree of paling in exoskeletal colour of captive juveniles. J. edwardsii retained its natural red colour when fed M. galloprovincialis but turned a light pinkish purple when fed P. canaliculus (James & Tong, 1997). Kittaka (unpubl.) found food conversion ratios (wet weight of food: gain in wet weight of lobster) for small juveniles fed mussels to be between about 5:1 (at 12°C) and 7:1 (at 20°C). Other ratios of 14:1 for 12-40g lobsters and 22:1 for 58-105g lobsters have been reported (James & Tong, 1998).
Disease Management
The high risk of disease is a major concern when culturing lobsters in elevated water temperatures (18°C). Problems can include build-up of external growths, infection of damaged limbs, development of the bacterial disease gaffkemia, carapace erosion, moult death syndrome and fungal diseases. The most important aspect of disease control in lobster culture is to reduce physiological stress. Stressed animals are more susceptible to disease, which can spread rapidly in dense cultures. Lobsters become stressed when subjected to improper culture conditions such as overcrowding, poor water quality, excessive temperature and inadequate diet. To minimise the risk of disease, rearing systems should be kept free of uneaten food, exuvia (cast moult) and dead animals that can harbour the disease agents. Intrusions such as bright lights, unnecessary movement and handling are also stressful. If these improper conditions are minimised, most researchers believe that disease will not be a major problem in lobster culture (Van Olst et al., 1980).
Water Quality Factors
The quality of the water supply is a major concern in all aquaculture ventures. The health of the lobsters depends on many complex and interlinked factors. Large or sudden fluctuations in water quality stress the lobsters, slowing growth and making them more prone to disease or moulting difficulties. Key water quality factors include temperature (16-18°C optimum, 10-20°C tolerable), dissolved oxygen (above 4.0 mg/L), oxygen saturation (below 105% saturation), water flow rate (above 0.5 L/min/kg of lobster), pH (7.6-8.2), and salinity (33-35 ppt tolerable). Each factor is inextricably linked to many others so a holistic approach is necessary to ensure the overall wellbeing of the lobsters. For example, oxygen consumption and the lethal oxygen levels depend on lobster body size, moult state, water temperature and salinity. Furthermore, information on both ammonia excretion rates and safe ammonia tolerance limits is required to optimise the design of the seawater circulation and waste treatment components of an intensive lobster culture system (Forteath, 1993).
The Japanese Market
The Japanese seafood market has some of the highest prices in the world for spiny lobsters, especially for species that look and taste similar to the favoured local species, Panulirus japonicus. This market can pay a premium for smaller (200-300 g) fresh whole lobsters, particularly for ceremonial and banquet occasions such as weddings where they have symbolic significance (C. Zame, personal comment). The Japanese demand for smaller lobsters is not met because of New Zealand's MLS restrictions on wild-caught lobsters. The MLS for wild-caught lobsters is measured by tail width. Female J. edwardsii must have a tail width greater than 60 mm and males a tail width greater than 54 mm to meet the MLS (Ministry of Fisheries, 1998). These measurements correspond to a weight of about 400g. There is no MLS for cultured lobsters (i.e. ongrown from pueruli) so they can be used for markets that prefer lobsters beneath New Zealand's MLS. Therefore, a cultured product will not compete with wild lobster in the existing commercial market. The smaller target weight will also reduce production costs.
Growth Rates in Culture
Growth rates of captive juvenile lobsters can vary depending on captive environment, water temperature, stocking density, feed, and water quality. In the wild, J. edwardsii can grow to 250-350 g in less than three years after settlement (McKoy & Esterman, 1981). The greatest growth rate of J. edwardsii in culture was at a constant 18°C water temperature. Booth & Kittaka (1994) estimate that a weight of 250-350 g can be achieved in two years. Various studies have shown different growth rates, with the highest being 0.098 g/day at 18°C with a density of 72 lobsters/m² (Hollings, unpublished), resulting in a final weight of 36g after one year from settlement. The lowest growth rate was 0.027 g/day at 10°C with a density of 59 lobsters/m² (Manuel, 1991), resulting in a final weight of 11.8g after one year.
Bioeconomic Analysis Considerations
The term bioeconomics is used to describe how the biological performance of an aquaculture system is meeting economic and technical constraints (Allen et al., 1984). The goal of most aquaculture ventures is to achieve a level of profitability or return on investment. Achieving profitability involves the following considerations:
  1. Estimating production costs under a given technology and local economic environment, and determining the values of certain variables that optimise (usually least-cost) the system.
  1. Determining the sensitivity of the output measures (mainly costs) to variation in parameter values.
  1. Assessing the market that exists or is projected for the product.
  1. Defining areas where research success would have high potential benefits.
Previous Profitability Assessment
The profitability of farming J. edwardsii in New Zealand was assessed by Hollings (1988). Findings indicated that lobster farming could be profitable. The assessment incorporated observations of juvenile growth and survival at continuous and elevated temperatures and a study of world lobster markets. It was estimated that each 300g lobster would sell for $14.50 each. Each puerulus would cost $2.00 to harvest, $6.00 to ongrow to 300 g, and $1.50 to process and transport. The cost of mortality would be $2.00 giving a total cost of $11.50. Each lobster would therefore return a profit of $3.00. In addition to the profitability analysis, the study identified the importance of further research into hatchery production of puerulus and cost-effective harvesting of puerulus from the wild. The estimates and assumptions used could be improved with further biological research and a costing study on different ongrowing systems.
Methodology: Technological Forecasting
Technological forecasting was used to determine when larval rearing techniques might be used to supply J. edwardsii pueruli as seed stock. Technological forecasting can be defined as the applying scientific methods to predict the future characteristics and timing of technology. To avoid ambiguity a forecast should define four elements (Twiss, 1992):
  1. What to forecast (the qualitative element).
  1. What measure to forecast (the quantitative element).
  1. When the event will occur (the time element).
  1. The likelihood of occurrence (the probability element).
Two qualitative delphi studies were applied because they best suited budget and time constraints. Extrapolative forecasting techniques were not used because little useful long-term quantitative data on larval-rearing was available.
The Delphi Method
Rand Corporation USA developed the delphi forecasting method during the 1970s. It is one of the more popular judgmental approaches to technological forecasting. The key feature of the Delphi method is that it is a group forecast based on anonymity, controlled feedback and iteration (Basu, 1977). A panel of experts make anonymous, subjective judgements about the probable time when a specific technological capability will be available. Results are aggregated and fed back to the group, which then uses the feedback to generate another round of judgements. After several iterations, areas of agreement or disagreement are noted and documented. Unlike many other forecasting methods, the Delphi method may not produce a single answer as its output. Often, a spread of opinions that reflect differing schools of thought are produced, which gives the forecast greater breadth and depth of information. Limitations of the Delphi method of technological forecasting include over-sensitivity of results to ambiguous questions and the difficulty in assessing the degree of expertise of the participants.
The forecast consisted of 2 studies; Delphi '97 conducted in October 1997, and Delphi '99 conducted in March and April 1999.
Harvesting Methodology: Collector Construction
Nine differently designed collectors were built between May and June 1997 to investigate if pueruli could be harvested cost-effectively. The eight new designs were a collaborative effort between Aqua BoP and NIWA. The performance of the devices, measured by collecting effectiveness and time taken to check and clear, was compared with the standard crevice collector. The nine collector types tested were: Bamboo bunch (BB), Bamboo sausage (BS), Crevice collector/standard (CC), Concrete pipe 1 (CP1), Concrete pipe 2 (CP2), Netting (NS), Plastic Pipe 1 (PP1), Plastic Pipe 2 (PP2), and Wooden Pipe (WP).
The collectors were constructed at Aqua BoP's ongrowing facility. After construction, the collectors were placed under the wharf at Gisborne because this area has a high natural settlement of pueruli. The wharf also provides shelter when deploying, checking and maintaining the collectors. The collectors were left to condition for three weeks to allow chemicals to leach out of construction materials, and also allow a natural biofilm to grow on the collector surface (conditioned collectors are more effective than new collectors). Each collector was suspended by rope from the underside of the wharf just above the seafloor. At low tide they were submerged in 3-5 m of water. The collectors were placed randomly to minimise possible bias from any localised effects.
Harvesting Data Collection
The pueruli in each collector were counted on 23 July, 7 August, 20 August and 16 September 1997. Each collector was carefully lifted to the surface of the water. A fine meshed net was then placed beneath the collector to catch any pueruli attempting to escape. The collector and the net were then gently lifted into a small boat and each collector was then methodically checked for pueruli. All lobsters in the collectors were removed and assessed for their development stage and for any damage during collection. Lobsters were then placed in a container of fresh seawater held in the boat. After each collector was cleared, it was placed back into the water and shaken to remove any accumulated debris before being lowered back into position. Once the collectors had been cleared, the captive pueruli were packed and transported to the Aqua BoP ongrowing facility in Papamoa.
Each collector was analysed in terms of cost to clear (per puerulus). Estimates of the unit cost for clearing different types of collectors were based on determining the time taken to clear each collector. The unit cost of each puerulus was then calculated using the formula: Unit cost of collecting each puerulus = (4T/P) × W, where T = mean time to clear collector (minutes), 4 = the number of collection times, P = mean number of pueruli caught per replicate, W = wage rate (assuming $15/hour or $0.25/min). The mean for the four collection dates were determined.
Transporting Methodology
To ascertain the upper stocking density, maximum travel time, and effect of seawater temperature an experiment was carried out in the laboratory to simulate commercial transport conditions. One hundred and forty-four stage 3 pueruli (P) and 144 stage 1 juveniles (J) were harvested from collectors in the Gisborne Harbour between 24 May and 28 May 1999 and were transported by road to the NIWA research facility at Greta Point, Wellington. Upon arrival the lobsters were acclimatised to the ambient temperature seawater tanks. There were no observed mortalities from the time of harvest to the beginning of the experiment three days later.
A factored experimental design was used to examine lobster survival, using the following factors: Two age groups stage 3 (P) and stage 1 juveniles (J); Two observation times survival at 6, and 9 hours; Two temperatures 14°C and 20°C; Three stocking densities 2, 4 or 6 lobsters/container (or 15, 30 and 45/litre); Three replicates of each treatment.
Transporting Experimental Setup
The required number of lobsters were put into 0.14 L lidded plastic containers filled with 0.13 L of seawater. Each container was floated in a constant temperature water bath. The containers were not aerated or agitated significantly. A 'Clayson Refrigerated' water bath was used for 14°C and a 'Grant' water bath was used for 20°C.
Data on class, stocking density, temperature, time and survival were recorded on a Microsoft Excel 97 Workbook. Lobsters that showed remote signs of life were put into recovery containers filled with fresh seawater and kept within 4°C of the original treatment temperature. There was a second, recovery observation, 8.5 hours after the start of the 6-hour treatment and 20.5 hours after the start of the 9 hour treatment. All lobsters that recovered were included in the survival results. The influence of class, time, temperature, and stocking density on survival rates were determined.
Ongrowing Methodology
To study the influence of four different stocking densities on the growth rate, 120 six-month old lobsters were reared at Aqua BoP's ongrowing facility. Two weeks before the first measurements (i.e., Day 0) were recorded, 120 lobsters were transferred from a large fibreglass tank to 16 white, round, plastic basins (0.275 m diameter x 0.145 m deep; 3.9 L) for conditioning. The flow rate to each white plastic basin was 1 L/min. The two-week 'conditioning' period enabled the removal of any lobsters that may have perished due to stress from handling. There were no deaths in the 2-week conditioning period between transferring the lobsters from the large tank to the small basins for the experiment. Growth was measured between February and June 1999.
The recirculated seawater was pumped continuously through mechanical and biological filters to remove animal wastes and disinfected with ozone. Water temperature was measured at least five times per week using a Carel in-line temperature probe. Ammonia, nitrite and nitrate levels were measured daily using a FasTest saltwater aquarium master test kit. Salinity was measured using a SeaTest specific gravity meter. Ammonia and nitrite levels remained below the measurable limits of the test kits. Nitrate levels remained below 100 mg/L and salinity between 33 and 35 parts/thousand. The oxygen content of the seawater on 22 April 1999 was 97% saturation, or 7.7 mg/L at 16°C.
Ongrowing Culture System
The lobsters were reared in 16 lidded utility baskets (0.25 m x 0.34 m x 0.18 m deep) distributed randomly within two larger fibreglass tanks (2.37 m x 1.2 m x 0.18 m deep; 512 L). They were submerged to 0.12 m (volume = 10.2 L) in recirculated (7-8 L min⁻¹) seawater and kept at a constant 16°C (±1°C) by a heat/chill unit. Each basket was provided with shelter in the form of a plastic waste pipe (0.2 m long, 0.1 m diameter) cut longitudinally. As well as the eight baskets, each large fibreglass tank housed approximately 400 non-experimental lobsters that could move freely in the large tank but could not enter the experimental baskets.
The lobsters were exposed to an ambient photoperiod (LD 8:16) during which the light period consisted of a mixture of subdued natural and artificial light. The lobsters were assigned randomly to density regimes: 3 lobsters/tank (35 lobsters/m², 175 lobsters/m³), 6 lobsters/tank (71 lobsters/m², 355 lobsters/m³), 9 lobsters/tank (106 lobsters/m², 530 lobsters/m³), and 12 lobsters/tank (141 lobsters/m², 705 lobsters/m³).
Feeding and Cleaning Protocol
The lobsters were offered an excess of 40-80 mm long cultured Greenshell Mussels, (P. canaliculus) purchased live from a local retailer. The mussels were presented to the lobsters in the half shell six days per week. All uneaten food and empty shells were removed each feeding time. Weekly cleaning involved lifting the baskets out of the water for ten seconds. This allowed any sediment to drain out freely and minimised any adverse cleaning disturbance to the lobsters.
On days 0, 50 and 121, the weight of each lobster was measured to the nearest 0.1 g with an electronic AND-HL200 balance. The CL was measured to the nearest mm with vernier calipers. Shortly before measurement, each lobster was placed between slightly dampened Chux multi-cloths to absorb any residual seawater and provide a temporary cover, which minimised stress and physical damage.
Any lobster that died during the experiment was replaced with a similar sized one to maintain stocking density. However, replacement lobsters were not included in the data analysis because of variability of individual growth rates. Replacement lobsters were identified by uropod clipping, which involved the removal of a diagonal-half of the outer-left uropod. Replacement lobsters had to be re-identified when the uropod regenerated, usually after three moults.
Bioeconomic Model Development
A baseline bioeconomic model was developed on a Microsoft Excel 97 Workbook using assumptions drawn from literature and expert opinion. It consisted of four linked components: biological, economic, physical, and a cash flow analysis. The biological component characterised the performance of lobster growth and survival. The economic component characterised market returns, export costs and the costs involved in harvesting seedstock. The physical component characterised production and capital requirements over the first 10 years of operation. The cash flow analysis predicted the financial performance of the operation over a 10-year planning horizon.
Key assumptions in the biological component included: 40,000 pueruli harvested per year, mortality rates of 5% for 1-year olds, 3% for 2-year olds, and 2% for 3-year olds, with lobsters reaching a saleable size (300 g) at the end of their third year. The feed conversion ratio was set at 7:1, meaning lobsters gain 1 g of body weight for every 7 g of mussel meat supplied. Stocking densities varied by age: pueruli at 100/m² (500/m³), 1-year olds at 50/m² (250/m³), 2-year olds at 30/m² (150/m³), and 3-year olds at 20/m² (100/m³).
Economic and Physical Assumptions
The economic component assumed a lobster selling price of $65/kg, with the farm trading 1,000 kg of CRA3 quota for harvesting 40,000 pueruli from the CRA3 area (East Cape to Wairoa). From Year 4, the farm would export 10,837 kg of 300 g lobsters annually. Quota lease was set at $15/kg/yr, harvest cost at $0.60/puerulus, and processing & transport cost at $10/kg. Feed price was set at $0.50/kg for Greenshell mussel meat.
The physical component assumed tank water depth of 0.2 m, with seawater costing $20/m³. The seawater would be changed 12 times per year at 20% each time. By Year 4, the maximum tank area of 4,195 m² would be reached, with building floor space of 2,097 m². Construction costs were set at $10/m² for tanks, $25/m² for the recirculation system, and $100/m² for buildings. Electricity cost was set at $65/m³ of system seawater.
Results: Sourcing Seedstock Forecast
Eight of the 10 participants from Delphi '97 forecasted that J. edwardsii larvae would be cultured on a commercially feasible scale between 2002 and 2021. Three participants in this group thought that J. edwardsii larvae would be cultured as early as 2002. After reading feedback from the first round, there were no changes to the original forecast timeframes.
In Delphi '99, eight out of 19 participants chose to respond by the deadline. Fifty percent of the responses indicated that between 2009 and 2015, with a 90% probability, larval-rearing techniques would be used by more than 50% of rock lobster farmers to produce J. edwardsii pueruli as seed stock. After reading feedback and opinions from the group, four of the eight participants altered their original timeframe by increasing the forecasted years. One participant decided that larval rearing techniques would never be able to supply commercial scale quantities of pueruli to rock lobster farmers.
Combined forecast frequencies from Delphi '97 and Delphi '99 are heavily grouped between years 2007 and 2021. Forecasts from Delphi '99 tend to be later than those from Delphi '97, with the period between 2017 to 2021 having the highest combined relative frequency.
Results: Harvesting Trials
A total of 33 pueruli were collected from the experimental collectors during the four observation times. More than half of these were collected on 7 August 1997. All collector designs were cleared of lobsters in less than 15 minutes and no pueruli were damaged or died whilst being removed from any of the collectors or during the subsequent transport to the ongrowing facility.
Concrete pipe collector one (CP1) collected the most (nearly 35%), followed by the crevice collector (CC) with 20%, and the wooden pipe collector (WP) with 17%. Concrete pipe collector one (CP1) caught 1.75 times more pueruli than compared with the crevice collector (CC). Concrete pipe collector two (CP2) collected approximately 10% of the pueruli. The netting design (NS) was the only collector that failed to collect a lobster.
In terms of unit cost, CP1 was the most effective. Each puerulus cost $1.80 to catch compared with $4.00 for CC and $27.00 for BB. The cost of labour was very high because it took a relatively long time to clear the bamboo bunches. The unit cost for the net sausage (NS) design was infinite because it did not collect any lobsters.
Results: Transporting Experiments
Of the original 288 Js and Ps, 51 survived the 14°C treatments and 8 survived the 20°C treatments. All Js and Ps survived at the lowest stocking density (15 lobsters/L), lowest temperature (14°C), and shortest time (6 hrs). At 14°C, survival rates fell significantly only after 6 hours and at densities of 30 and 45 lobsters/litre. Survival rates at 20°C were poor over all densities and time periods, except for 15 P for 6 hours. For this configuration, all the Ps survived compared with only 33% survival for the Js. For densities of 30 and 45/litre (20°C) all lobsters perished before the 6-hour observation. In general, the Ps had better survival rates than the older Js. The exception was at 45 lobsters/L, 14°C, and 9 hours, where 17% of the Js survived and no Ps survived.
The findings suggest that lobsters at different post-larval stages (P1-P3, J1-J3) are more likely to survive. The following factors may decrease mortality when transporting Ps and Js: Minimising stress through careful handling; Using full and fresh oceanic seawater for transport media; Aerating the seawater prior to despatch; Keeping temperatures below 20°C, ideally at 14°C; Allowing for lobster recovery at destination.
Results: Ongrowing Experiments
At Day 0, the lobsters weighed between 5.6-18.6 g, had carapaces 20-34 mm long, and had no missing appendages. The sex of each lobster was not recorded. As there were no significant statistical effects, data for stocking density and temperature were pooled. There was no statistically significant effect of density on growth (both in WT and CL). However, fastest overall growth was observed at the lower stocking densities of 3 and 6 lobsters/tank. Fastest relative growth (in CL and WT) was also observed at the lower stocking densities of 3 and 6 lobsters/tank.
Sixteen lobsters died during the 121 days. Most of the deaths (15 lobsters; 94%) occurred before Day 50. Eight of these mortalities were the direct result of a pump failure on Day 9. The other 8 lobsters that died were cannibalised either while moulting or immediately after. A large proportion (44%) of the total mortality occurred at the highest stocking rate (12 lobsters/tank).
Lobster growth at the higher stocking densities (9 and 12 lobsters/tank) was slower than those at the lower stocking densities (3 and 6 lobsters/tank). There was no statistically significant effect of stocking density on growth but there was a trend for growth rate to be increasing at densities of 3 and 6 lobsters/tank and growth rate to be decreasing at densities of 9 and 12 lobsters/tank. Lobster mortality was highest at the highest density (12 lobsters/tank).
Results: Bioeconomic Analysis and Conclusions
The baseline bioeconomic model for a hypothetical farm assumed harvesting 40,000 pueruli annually and growing them to a saleable size (300 g) by Year 4 with an overall mortality of 10%.
The required working capital would be $1,000,000. The model showed an annual net cash position of $287,100 and cumulative cash position of $859,200 by the 10th year of operation based on annual sales of 10,837 kg at $65/kg. A farmer could expect a return of $19.50 per lobster less costs of $14.48. The model indicates that the highest cost components in the first 10 years are processing/transport (20.7%) and labour (19.7%), contributing to 40% of the total cost. Other significant cost components are electricity (10.7%), pueruli (10.7%), feed (9.0%), and water (7.0%).
Sensitivity analysis showed that profitability is very sensitive to factors such as the farm size, processing and transport costs, and sale price. Increasing the amount of quota traded has the largest positive effect. Other scenarios that have significant positive effects are an increase of sale price to $75/kg, increased growth rates, improved stocking densities and improved efficiencies in feed. A drop in sale price to $55/kg has the largest negative effect, followed by increased mortality and increased processing and transporting costs.
The study concludes that commercial feasibility will be affected by these key areas. The potential of J. edwardsii aquaculture in New Zealand will continue to benefit from further research. Future research should include: gaining a better understanding of larval nutritional requirements; quantifying puerulus settlement and identifying environmental factors; analyzing collector effectiveness including overall costs; and conducting a more detailed feasibility study including site selection, building and equipment design, and marketing issues.