Graphical distribution influences fish farming techniques and the above diagram shows that this is mainly a tropical species but capable of considerably extended climatic range. Although much is known about this species, 'closing the loop' on the breeding cycle is still proving to be a problem even after twenty five years of research.
The health and breeding performance of broodstock tends to be less than that of caught wild stock. This is alarming as production ponds can be left empty due, solely, to lack of spawning females. McVey (1983) discusses hatchery approaches and associated problems of holding broodstock. He talks of the high fecundity of approximately 600,000 eggs per 120g specimens, which has aided their significant natural tropical distribution as can be seen from the map above and which is known to extend to Fiji in the east. However there would seem to be unknown factors of stress that reduce the breeding performance of captive stock. For example, captive P. monodon specimens held in Fiji could be killed instantly by one sharp bang on the glass of the aquarium.
LIFE HISTORY SUMMARY (from AIMS Online Publications)
The life history of the black tiger prawn in Australia is poorly understood. This account is mainly based on observations made over several years by broodstock suppliers from the Townsville to Cairns area in north Queensland. Additional information has been sourced from life history accounts of P. monodon from the Philippines and Indonesia (Motoh 1981). Where possible the total length measurements reported by fishers have been converted to carapace length and weight using the regression formulas developed by Motoh (1981).
The life history of the black tiger prawn may be divided into six phases. The first, the embryo phase, is planktonic/benthic and lasts only 12-14 hours. The second, the larval phase, is planktonic and lasts approximately 20 days. Aspects of the next four phases – juvenile, adolescent, sub-adult and adult are shown below.
'EMBRYO AND LARVAL PHASE Adult P. monodon are believed to spawn predominantly in inshore and to a lesser extent in offshore waters. The eggs are spawned by the female in the water column and soon after sink towards the bottom. The eggs develop through the embryonic phase and hatch out in approximately 12-14 hours.
The larvae go through 6 naupliar, 3 protozoeal, 3 mysis and 3 or 4 megalopa substages, with each substage lasting approximately 1.5, 5, 4 to 5, and 6 to 15 days respectively. The megalopa and early juvenile stages are collectively termed postlarvae, or fry for commercial purposes.
The postlarval stage begins on day 1 of the megalopa substage. The larvae remain in the plankton for 2-3 weeks and are believed to migrate towards estuaries and mangroves. Five-day-old postlarvae (PL5), approximately 16 days post-hatch at 29°C, end their planktonic phase and settle on the bottom. At this time postlarvae preferentially grasp and cling to filamentous matter, grass, twigs and the like which makes them difficult to sample accurately. It is believed that they migrate into estuaries and mangroves and remain in these nursery grounds until the following summer. In northern Queensland recruitment occurs annually as two major seasonal cohorts – the first from a spawning occurring in late summer/autumn (mid-February to April) and the second in spring (late August to October/November).'
The graphs below shows that seasonal spawning is triggered by a reduction in salinity and a coinciding rise in temperature. These are the basic conditions of the wet or monsoon season. These conditions can easily be simulated in a tropical hatchery however successful spawning has centered on eyestalk ablation of wild caught females.
The Atlantic Salmon is a cold water species that migrates to the headwaters of streams to spawn at temperatures just above freezing. Atlantic salmon cage farming has become a major fishery in Tasmania from imported landlocked broodstock in 1983.
All the aspects of its life cycle have been studied and researched. Atlantic Salmon is routinely produced in hatcheries in Tasmania to supply industry requirements. Atlantic Salmon is a highly priced high demand species with existing acceptance in this country.
Life Cycle Of Atlantic Salmon
"Wild Atlantic salmon vary in appearance during their lifetime. Until the early 19th century the life cycle was not understood and documented, and Parr and Smolt were assumed to be different species of fish.
Eggs: Pea-sized orange eggs are deposited in riverbed gravel in autumn, and hatch the following early spring. As the eggs develop, the eyes of the developing wild salmon can be seen through the semi-transparent membrane.
The partly transparent alevin hatch and remain hidden in the riverbed gravels, feeding from the attached yolk sac. They are about 2 cm or less than 1 inch in length.
Fry: Wriggling up from the gravels, fry begin feeding on microscopic life in the stream. They eventually reach a length of 5 to 8 cm./2 to 3in. before transforming into parr.
Parr: The vertical markings, called 'parr marks' appear, with a single red dot between. Parr remain in the river for 2 to 6 years, depending on water temperatures and food availability.
Smolt: At a length of 12 to 24 cm/4.7 to 9.5 in. a springtime transformation of the parr takes place into smolt. A silvery sheen replaces the parr marks, and internally they undergo a complex transformation to survive in saltwater. On the downstream journey the odors of the smolt's native river are imprinted on its memory, to be recalled when it returns to spawn.
Adult: Silvery hunters, adult wild salmon live one or more years at sea. Most populations follow lengthy migration routes to waters off southwestern Greenland where they grow rapidly on a diet of crustaceans and small fish. Other feeding grounds exist, such as waters surrounding the Faroe Islands north of Scotland, and some populations may stay closer to home rivers, such as those from the inner Bay of Fundy Rivers. Wild salmon that return after one year at sea are called GRILSE.
Adult salmon return to home rivers, entering freshwater between April and November. Once in freshwater they stop feeding, living off accumulated fat reserves.
In late fall the wild Atlantic salmon spawn. The female digs a 10-30cm/4-12 in. deep nest called a REDD in the gravel bottom of the stream. Her eggs and the milt from an adult male are released into the redd, the gravel replaced with additional tail thrusts. In some cases sexually mature male parr manage to fertilize a percentage of the eggs. In the painting parr are seen swimming nearby, looking for an opportunity. The female may lay 1,500 eggs or more for each kg./2.2 lb of body weight. - Thus a 12 pound female salmon will lay about 8,000 eggs, completing the life cycle".
Atlantic Salmon Are now listed as endangered in the USA
Barramundi are known as Sea Bass throughout most of their Asian distribution. They have a considerable tropical distribution as is demonstrated below.
Life Cycle Chart of Barramundi
Barramundi (Lates calarifer)
Barramundi broodstock are large fish of approximately 0.5- 1 meter in length and as such require large, usually saltwater recirculating, broodstock holding tanks with available support conditions for temperature and light control. Barramundi need to have a suitably nutritional food ration which allows for natural maturation and not excessive fat build up. The fish need to be handled in such a fashion that they are not stressed by their surroundings as this appears to inhibit normal egg growth. (pers observation Broome Hatchery 2000).
Once the eggs have hatched feeding commences on about day 2 at 29 degrees C. Feeding normally consists of a mixture of algae and rotifers and a degree of nutritional enrichment with HUFA’s. The barramundi are capable of significant reduction in salinity and even freshwater after day 15 (Maneewong 1986) but are usually maintained in 20 ppt due to the need for cultured feeds. Some more extensive hatchery designs can take advantage of this life cycle adaptation to remove the larvae and or fry to bloomed freshwater pond culture methods and utilise the natural freshwater zooplankton. Maneewong (1986) discusses several different approaches to feeding, including freshwater zooplankton in seawater. The varying approaches relate to culture density and larval survival, as they become cannibalistic at high densities. He describes the different feeds and relevant particle size for the stages of growth. All these factors revolve around feed production and the systems and procedures necessary to culture and house live feeds and larvae. The size and shape of the tanks can be utilised to be self-cleaning and assist in removal of waste and uneaten feed. These systems would require a reasonable degree of water exchange so the hatchery design must cater for that requirement.
In comparing any aquaculture species, in hatchery design, function and complexity, the key factor is always survival. Relatively speaking, the spawning process, for any commercial species is the easiest component of any aquatic hatchery protocol when compared to the complexities of sustaining the survival of the cohort after hatch.
When comparing life cycles of species such as Barramundi (Lates calcarifer), Black Tiger Prawns (Penaeus monodon) and Atlantic Salmon (Salmo salar) the commercial hatchery design comparisons are relative to climatic zone, nutritional complexities, feed particle size per larval size, maturation complexities and the commercial factor of return on the cost of applying adequate technology. Tank design per individual species culture is also highly significant but has been adequately covered with various parabolic shapes and self cleaning design efficiencies. These factors all directly affect cohort survival.
Barramundi and P. monodon could easily be produced in the same hatchery as the larval survival requirements are quite similar and they both offer a considerable commercial output return for a hatchery business. Hatchery efficiency and technology development in all three species is highly significant as they are all highly prized, and priced, aquaculture commodities. The aquatic hatchery processes represent a level of technical expertise that supports the commercial application potential for that species. Simply put, you cannot afford to over capitalise on your hatchery function nor can you afford to under capitalise and that commercially effective point is hard to distinguish. But it is a highly commercial key factor. For example; between Sydney and the Queensland border there are many millions of dollars in 'dead hatcheries' of both fresh and saltwater applications where inappropriate technology was applied. Research does not equate to commercial up-scaling and every new venture should show considerable data on commercially orientated pilot-scale development. This has not been the situation in the past and the results have been highly damaging to Aquaculture as an emerging industry.
From the distribution maps, both P. monodon and Barramundi are tropical species and have similar distributions which is why they can be cultured in the same hatchery. And naturally, it would be commercially impractical to hold and breed salmonids, which breed at 3-4 degrees C. in freshwater. Both tropical species require similar husbandry input to manage the spawning and larval rearing processes. For example the temperature requirements are similar at about 28- 30 degrees C. Both the fish larval stages and the 5 crustacean larval stages require the same rotifer and brine shrimp type diets or micro encapsulated replacement diets for commercially acceptable survival. As well, larval survival, for both species, is significantly enhanced from nutritional enrichment of HUFA’s. However in salmonid culture the nutritional enhancement is most significant if carried out on the broodstock, so the egg yoke contains the essential fatty acids. From swim-up, first feed Atlantic Salmon fry are totally fed on a formulated artificial diet, which continues right through their culture life.
P. monodon have a high fecundity (600,000 eggs/120g) (Primavera 1983) and are usually setup as individual spawning's in most modern hatcheries. No male is present, as a spermatophore would have been implanted at the previous female moult. Spawning can be achieved in 100-500 litre tanks and the fertilised eggs removed and rinsed and then added to the 15,000 litre tanks on flow through systems. The trend is to keep the eggs of each spawner separate as a means of identifying potential disease problems at the post larval stages, The PL’s are subjected to a salinity stress test as a way to induce viral disease symptoms prior to shipment to the farms (pers. com. Gold Coast Marine Hatchery). There is also a trend in Eastern Australia to set-up individual farm hatcheries as a potential means to lower costs and reduce the risk of disease introduction.
In comparison salmonid broodstock are inoculated against disease and maintained separately and isolated from culture sites. Due to the relatively low fecundity (2000 eggs/kg) many ripe females are hand stripped and eggs are fertilised and cultured as one batch system (pers. com. John Purser 2002).
Barramundi broodstock are usually all environmentally manipulated within the one broodstock holding system which is an integral part of the hatchery for the majority of fish hatcheries. Both male and females are present and gonad sampling is carried out when regulated spawning time is near. If the condition of the eggs is adequate, which is usually taken as an egg diameter of 0.5mm the fish can be injected with an LHRH-analogue pellet to enhance egg maturation and spawning. The semi buoyant eggs are collected in effluent-side catch bags and sumps of approximately 400um, which drain from the top water level. The eggs can then be removed, washed and volumetric counted prior to adding to the hatching tanks at specific densities.
Due to the high fecundity of both tropical species the number of broodstock required is much less than that of Atlantic salmon so there is a completely different emphasis placed on broodstock management.
For example: A tropical hatchery such as Broome TAFE Aquaculture Hatchery was designed to test this tropical type of multi functionality as a prelude to the development of the Multi Species Hatchery which is just now finishing construction. (pers com. Mark Johnston WA Fisheries Broome). This hatchery can run simultaneous batch culture of both the tropical species.
Both Atlantic Salmon and Barramundi are euryhaline (live in both fresh and saltwater) species however Atlantic Salmon is a cold water species, with a relatively low fecundity, The salmon will spend a significant proportion of their adult life in the polar regions (Laird 1988) only returning to freshwater to breed. It is interesting that salmonid species will return to the same location to breed and fisheries or ranching industries have been established by capitalising on this aspect of their life cycle. Salmon breed in the coldest winter periods in temperatures of 2-4 degrees C. where as Barramundi breed at approximately 28-29 degrees C. and travel from freshwater to saltwater to spawn. One species moves into the freshwater and the other tends to move to the saltwater. In many ways the two species have directly apposing life cycles.
For example in spawning, one is freshwater one is saltwater, one is hot one is cold. Barramundi eggs are quite small 0.7- 1mm and salmon eggs are relatively large. Barramundi have a high fecundity and the salmon have a relatively low fecundity and one requires artificial hormonal maturation and one does not. These are factors in their life cycles which are reflected in the hatchery techniques and species protocol.
In the Philippines the spawning of P. monodon can be carried out year round The significance of climate on the life cycle is directly reflected in the application of the species in the hatchery environment. However it seems unusual that unknown aspects of this particular species make broodstock management difficult in current hatchery applications. Indeed in 2003, the significance of the inconsistencies led to 50% of prawn production ponds in Queensland being left empty. Due directly to a lack of post larvae production as a result of reduced numbers of wild spawners. This point makes it obvious why life-cycle control and broodstock management are commercial necessities.
These semi-pioneering circumstances reflect the same situation that occurred with commercial barramundi development and research in the 1980’s. The life cycle was known but hatchery results were inconsistent. Both these species have many similarities in respect of hatchery and commercial application. The development of consistent life cycle controls and broodstock management make good comparisons as they time line the aquaculture development of each species.
Barramundi breeding is now becoming routine with commercial intensive farms with specific stock and restocking requirements as well as semi intensive farm production. Broodstock management system designs are available. Nutritional requirements are known and the ability to control maturation to suit hatchery requirements is well documented as is demonstrated in the Barramundi hatchery procedure protocol. These developments describe the similar direction of the current development of P. monodon. However crucial hormones have yet to be identified that could limit the stress factors and allow normal maturation, which is still signified by unilateral eye stalk ablation techniques.
The importance of adequate nutritional broodstock diets is a significant factor in sustainable broodstock and routine maturation. And it is noted (Millamena 1986) that good broodstock diet information is scanty for P monodon.
In comparison, Atlantic Salmon and Barramundi have quite documented broodstock/hatchery history where results can be duplicated on mass with sustainable results. These highly successful results reflect commercial stability necessary for growout intensification. For example: the prawn industry in Australia suffered a major setback in 2002-2003 season simply because there were reduced numbers of wild spawners. Had the prawn industry gained commercial hatchery control over broodstock that event would not have occurred.
The successful spawning and larval rearing of any species is a direct parallel of how well the hatchery design reproduces species specific environmental and nutritional requirements. The generalised fish hatchery techniques protocol,below, is a representation of a sea bass nursery but it could almost represent the nursery plan for generalised penaeid production. In contrast, the salmonid first feed particle size would approximate artemia but in salmonid production no live feeds are used.
The quality and size of the feed particles is quite significant in supporting high survival rates up until the larval/juvenile stages are completed. This essential factor for acceptable cohort survival is demonstrated in the figure below with differing quality feeds for sea bass.
Aquatic growout is, in many ways, exploitation. There is nothing natural about the culture densities required to achieve commercial production. The ability of species to exist and and grow at high density is a major factor influencing growout design and farming intensity.
Roland (1992) talks of the ‘right stuff” where he refers to the species characteristics and life cycle factors that give a species aquaculture potential. For example, a species should exhibit rapid and uniform growth, be amenable to artificial feeds, have known diseases, attractive appearance and colour, high marketing attributes and established hatchery protocol. All these traits are factors of life cycles that influence initial potential for establishing commercial growout.
For example; there are super intensive, temperature controlled tank culture systems for barramundi now becoming popular in Eastern Australia. Aspects of the Barramundi's life cycle have allowed them to be exploited in a somewhat distasteful manner. The principal of these systems is high density and quick turnover where 30% mortality is acceptable (pers. work experience Infinity Fishfarms 2001). But such systems appear to work and make a profit, if profit is the only driving motivation to being in aquaculture. Although, ethical questions are still to be adequately addressed within society, there are still valid issues over the quality of the flesh, and consequently the long term profitable viability of production in such 'high tech' systems. In any event, any type of system, using very high culture densities, does appear to be unsustainable in the long term. And this has been hugely demonstrated in Asia with P. monodon culture and in Taiwan as well as other countries in the Asian Pacific region. This type of culture has been termed "boom and bust".
It is well known that single sex culture is often highly desirable (pers. com. N Forteath 2002) particularly with species like salmonids where some males mature early, fight, create stress, and lower the FCR as a result of gonad production. These are the life cycle traits that influenced research into triploid and polyploid (variations in the number of chromosomes) procedures as well as sex reversal techniques to produce one sex culture. These research efforts were attempts to change the life cycle patterns and increase control over FCR’s (food conversion ratios) and overall commercial applications.
The success with high density Barramundi may be linked to a major factor of their life cycle as well. With Barramundi, they tend to be immature up until approximately 400mm in length (Davis 1986) and the market size is approximately 350-400mm for these high density cultured ‘blackish’ fish. It is well known that immature fish will school and behave more as a function of the cohort than as individuals and as such are more adapted to high density culture.
However the advantage of immature growth is much more complicated with salmonids as they can only go from freshwater to saltwater during the smoltification process. If smoltification is missed the fish must be held in fresh water until the following year as shown in the life history diagram above
Finally and most importantly, it should be clear from the comparison aspects above, that technological application to aquaculture must be directly related to individual projects, species and their individual commercial potentials. This is true even in multi function hatcheries. Two farms,even side by side, will have completely different financial structures and production dynamics and this directly affects farming strategies. An individual commercial plan based on evaluated marketing direction is only the basis for profitable aquaculture as market forces are unstable over most culture cycles. "One needs as much applied marketing management as one applies to pond productivity management". The only situation this statement is not true is where the hatchery is government run. And it is unfortunate that many commercial ventures develop designs based on government run projects without considering the commercial implications. Government hatcheries and their aquaculture farms are never profitable.
"For example; between Sydney and the Queensland border there are many millions of dollars in 'dead hatcheries' of both fresh and saltwater applications where inappropriate technology was applied. Research does not equate to commercial up-scaling and every new venture should show considerable data on commercially orientated pilot-scale development. This has not been the situation in the past and the results have been highly damaging to Aquaculture as an emerging industry in Australia".
Running a successful project is a major ask for any single person and that is why delegation of responsibility and team orientated goals are effective tools. We aim to be part of your team. In a smaller venture ASA can supply that extra input into assessing and further developing sales. We operate in that instance as a "no sale-we fail' back end cost. We aim to provide a service not an added financial bourdon.
Aquafarmer provides realistic commercial aquaculture support and not product sales, although we do sell selected products.
AIMS Publications 1999. “The supply of the black tiger prawn for aquaculture’. AIMS Online Publications. (monodon tp-broodstock-02-html)
Davis. T. L. O. 1986. ‘Biology of Wildstock Lates calcarifer in Northern Australia’. Manaagement of Wild and Cultured Sea Bass/Barramundi. ACIAR Proceedings No. 20.
Grey, D. L. 1986. ‘An Overview of Lates calcarifer in Australia and Asia’. Manaagement of Wild and Cultured Sea Bass/Barramundi. ACIAR Proceedings No. 20.
Laird, L. M. & T. Needham. ed. 1988. ‘Salmon & Trout Farming’. Pub. Ellis Horwood Limited. ISBN 07 458-0025-4
Maneewong, S. 1986. ‘Research on the Nursery Stages of Sea Bass (Lates calcarifer) in Thialand’; Manaagement of Wild and Cultured Sea Bass/Barramundi. ACIAR Proceedings No. 20.
N.S.W. Fisheries Leaflet No 8. 1980. ‘Biology & Life Cycles of Prawns’.
Roland, S. J. 1994. ‘The silver perch Bidyanus bidyanus, and its potential for aquaculture’. Silver Perch Culture, Proceedings of Silver Perch Aquaculture Workshop. Grafton Fisheries research Station. April 1994.
Shigueno, K. & D. Agr, 1974. ‘Shrimp Culture in Japan’ Ass. for International Technical Promotion. Tokyo, Japan.
‘Biology and Culture of Penaeus monodon”, 1988. Brackishwater Aquaculture InformationSystem Aquaculture Department Southeast Asian Fisheries Development Centre. ISBN 971 8511 14-8