AU2008201617A1

AU2008201617A1 - Aquaculture

Info

Publication number: AU2008201617A1
Application number: AU2008201617A
Authority: AU
Inventors: Rick Dalla Rosa; Geoff Sayers
Original assignee: Pearl Shell Tech Pty Ltd
Current assignee: PEARL SHELL TECHNOLOGIES Pty Ltd
Priority date: 2007-04-12
Filing date: 2008-04-11
Publication date: 2008-10-30

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant(s): Pearl Shell Technologies Pty Ltd Invention Title: Aquaculture The following statement is a full description of this invention, including the best method for performing it known to me/us: P81537.AU Pal Sol FAng Application 2008-4-11 2 00 0 AQUACULTURE

FIELD

SThe present invention relates to compositions and methods for reducing or inhibiting the fouling of marine or aquatic shellfish and apparatus used in aquaculture.

BACKGROUND

0 Shellfish aquaculture poses the problem of fouling of the Sapparatus used in aquaculture, as well as fouling of the 00 10 animals themselves. The shells of oysters, muscles, scallops etc are surfaces for settlement of fouling c organisms. Thus shellfish aquaculture necessitates regular shell cleaning as well as cleaning of the apparatus to enable growth, survival and marketability of the shellfish.

One example of the problem facing shellfish aquaculture relates to pearl oysters. After successful impregnation of pearl oysters with a graft from which a pearl grows, the pearl oysters are placed into panels on long lines in open waters such as lakes or seas. Long lines are typically about 100 metres long, made of polypropylene or nylon and have holding panels suspended at approximately 1 metre intervals. The holding panels typically contain 6 to 8 shells, depending on shell size. Pearls grow by producing nacre, a complex mixture of calcium and protein. The nacre forms a hard, lustrous layer on the grafted cell. Hundreds of such layers are required to produce a pearl.

Interruptions or disruptions to the nacre secretion and layering may result in imperfectly shaped pearls. Regular shell cleaning and associated rough handling is such a disruption.

The subsequent exposure to the natural aquatic environment subjects the shells to attack by natural marine fouling organisms. These fouling organisms may be boring types which bore through the shell causing damage to a growing N \M lbourne\Cases\Patcnt\61000-61999\P61537 AU. I\SpeisP61 537AU I Specification 2008-4-11 doc 3 00 0 pearl, as well as rendering the shell less suitable for Suse in jewellery. Other fouling organisms include squirters and longish weeds. As a result of this exposure, the shells and equipment (such as the holding panels, long lines and buoys) require regular cleaning to remove unwanted organisms.

ND The typical cleaning rate is approximately once each Sfortnight, depending on many factors including the 00 10 environmental conditions, weathering seasons and nutrient Slevels in the water.

Therefore, protection against marine fouling, and a reduction in cleaning frequency has a major impact on labour expenses and other costs in the aquaculture industry.

SUMMARY

According to one aspect, the present invention relates to a process for reducing or inhibiting the fouling of marine or aquatic shellfish comprising the steps of: 1) contacting shellfish with a pre-treatment agent, and 2) treating the shellfish with an antifouling composition.

Preferably, the method comprises contacting the antifouling composition with the shellfish at a temperature between 40 and 70 0

C.

The process enables the frequency of cleaning marine or aquatic shellfish to be reduced. In one embodiment of the invention, the process is effective to the extent that the necessity to clean the shellfish due to fouling is reduced to approximately once every 3 4 months. In another embodiment, the process is effective to the extent that the necessity to clean the shellfish due to fouling is avoided altogether.

N.\Micbouwne\Cases\Paten\61 000.61999\P61 537AU. I\Specis\P61537 AU I Specification 2008-4-1 1 doc 4 00 SThe pre-treatment agent may comprise an amine.

The antifouling composition may comprise microcrystalline wax, paraffin wax and natural hydrocarbon wax.

The antifouling composition may further comprise an IO adhesion promoter and/or a plasticiser.

00 10 According to a further aspect there is provided a multicomponent composition for reducing or inhibiting the c fouling of marine or aquatic shellfish, the composition comprising a first component which is a pre-treatment agent and a second component which is an antifouling composition, wherein in use the first and second components are applied sequentially to marine or aquatic shellfish to reduce or inhibit fouling of the shellfish.

DETAILED DESCRIPTION Process The process of the present invention involves two steps.

First the shellfish is contacted with a pre-treatment agent and subsequently the shellfish is treated with an antifouling composition.

The shellfish is a marine or aquatic shellfish, and is suitably cultured (or farmed) shellfish. Suitable types of shellfish which can be subjected to the process include scallop, abalone, pearl, mussel, clam, oyster, edible oyster and the like. The shellfish can be treated individually or several at a time. The shellfish can be in a holding basket, several holding baskets or a line of holding baskets. All farming equipment generally utilised in aquaculture, for example panels, lines, buoys, markers, mesh bags, trays, pots, floats, cages, etc can be treated in accordance with the invention. The shellfish can be at any stage of growth. For example, in the case of an N \Melbourn\Cascs\Paent\61000-61999\P6]537AU I\SpecisP61537 AU I Specificaion 2008-4-1 doc 00 oyster, pre-treatment and contact with the antifouling k composition can take place on the spat, the young oyster, Sand/or the adult oyster.

The utilisation of the pre-treatment agent in the process of the present invention promotes subsequent adhesion of the antifouling composition to the shellfish. It assists ND in repelling water from the surface of the shellfish and generally means that the shellfish are not required to be 00 io dried for long periods after removal from the long lines Sin open water and prior to contact with the antifouling (1 composition. This is a time saving feature of the present invention. It also has the added advantage that the shellfish are not harmed or damaged by having to dry in the sun, or be forcibly dried with hot air for long periods.

The pre-treatment agent and the antifouling composition are well tolerated by the shellfish at all stages of their growth. The pre-treatment agent and composition can be applied to the entire surface of the shellfish, not merely the shell. This does not adversely affect the ability of the shellfish to breathe and feed, which would result in premature death of the shellfish.

Pre-treatment and subsequent contact with the anti-fouling composition can take place by any suitable means including painting, spraying, electrostatic spraying, brushing and dipping. Spraying air blowing combination or dipping air blowing combination is preferred for the pre-treatment step.

Preferably, the pre-treatment agent is sprayed on to the shellfish, followed by blowing with air such as a gentle blast of pressurised air.

Generally, the shellfish and holding baskets holding the N Melbournc\Casesl\Paten\61000-61999P61 537.AU I\Spec i\P6 1537.AU.I Specificaiion 2008-4-11 doc -6 00 O shellfish are removed from a long line of holding baskets Sin open water. The holding basket containing several shells is sprayed with the pre-treatment agent, drained and air blown. The length of time taken to drain the shells is dependent on the number of shells being drained.

Generally, a holding basket containing 6-8 shells will require a few minutes, approximately 1-3 minutes, ND preferably 1 minute, to drain adequately and remove excess Spre-treatment agent.

(<N

00 Individual shells or a holding basket containing several shells are then contacted with an antifouling composition.

The antifouling composition generally acts as a physical barrier that resists adherence of unwanted fouling entities to the shellfish surface and/or the aquaculture equipment.

The shellfish are preferably dipped into the antifouling composition, until adequate coverage of the shellfish occurs.

The antifouling composition is preferably at a temperature between 40 0 C and 80 0 C, further preferably between 40 0 C and 70 0 C, even further preferably between 50 0 C and 60 0 C at the time of contact with the shellfish. The shellfish are then cooled before their return to open water. This can be achieved by any suitable cooling means, for example, placed in a cool room, contacted with a jet of cool air, and/or contacted with a cold liquid that they are able to tolerate. Preferably, the shellfish are sprayed with a liquid. The liquid may be water at ambient temperature.

The liquid is suitably sourced from the natural living environment of the shellfish i.e. sea water, lake water etc.

Contact of the antifouling composition with spats and N:\Mclboune\Caes\Paten,\61000-61999\P61 537.AU. I Specis\P6 37 AU I Specifiacion 2008-4-11 doc 7 00 young shellfish, as well as adult shellfish, does not cause damage or harm the shellfish, partly because of the Srelatively low temperatures at which the antitouling composition is applied as described above. Also, the antifouling composition does not prevent breathing and feeding of the shellfish, which would result in death of the shellfish.

NO

Depending on the length of time the shellfish have been in 00 10 the open water, there can be a certain degree of fouling of the shellfish. Therefore, the process may include CI chipping and cleaning of the shellfish in the usual manner known in the art, to remove unwanted organisms, crustaceans, weeds, etc prior to contact with the pretreatment agent and antifouling composition. The holding basket, ropes, and any other equipment can also be treated in the same manner to reduce the frequency of cleaning or to prevent fouling altogether.

It is envisaged that if the long lines of holding baskets containing shellfish are moved so that they are positioned differently and preferably into an area of open water not previously utilised in aquaculture, and if they are treated with the pre-treatment agent and/or antifouling composition of the invention prior to being placed in open water, it is likely that there will be virtually no fouling, thus avoiding the necessity to clean the growing shellfish.

It is also envisaged that if young spats are treated before being placed in open water and are placed in a position not previously utilised in aquaculture, it is likely there will be virtually no fouling of the spats and the resulting growing shellfish, thus avoiding the need to clean altogether.

Pre-treatment Agent N:\Melbournc\Casps\Patent\6 1000-61999\P61]537AU I\Spccis\P6137AU I Specification 2008-411 doc 8 00 0 The pre-treatment agent is used to repel excess water from Sthe shellfish. Advantageously, it also reduces the Sprobability of barnacle spores adhering to the shellfish surface.

The pre-treatment agent preferably comprises an amine. The amine may be selected from a primary, secondary or IND tertiary amine. It may comprise aliphatic, aromatic and/or Saliphatic-aromatic amines.

00 The term amine includes optionally substituted c methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-Propylamine, di-npropylamine, tri-n-propylamine, isopropylamine, nbutylamine, isobutylamine, sec-butylamine, tertbutylamine, cyclohexylamine, benzylamine, aphenylethylamine, P-phenylethylamine, ethylenediamine, Tetramethylenediamine, hexamethylenediamine, tetramethylammonium hydroxide, aniline, methylaniline, dimethylaniline, diphenylamine, triphenylamine, o-nitroaniline, m-nitroaniline, p-nitroaniline, 2,4dinitroaniline, 2,4,6-trinitroaniline (picramide), ophenylenediamine, m-phenylenediamine, p-phenylenediamine, p-aminobenzoic acid, sulfanilic acid and/or sulfanilamide.

Amines may also include a saturated and/or monounsaturated fatty acid amine with a carbon chain length within the range of C 6

C

24 or with a carbon chain length distribution within this range.

Preferably the pre-treatment agent is selected from one or more fatty acid amines with a carbon chain length distribution of Cio C 18 One suitable amine is tallow amine.

Preferably, the amine pre-treatment agent is an amine salt. The salt is preferably an organic acid salt.

N Mlborn\Cases\PaenL\6 100061999\P6 1531AUU I .Specis\P(5137 AU. I Specificaion 2008-4. I doc 9 00 The organic acid used for the salt formation may be Sselected from the group consisting of formic acid, acetic acid, benzoic acid, propionic acid, malonic acid, oxalic acid, kemp's tri acid and EDTA. Organic acids that contain phosphorus are also suitable, for example HEDP and DTMPA.

IND The pre-treatment agent is suitably applied in solution 0 form at a concentration of 2-20%, preferably 2-10%, and 0 10 further preferably 4-5% by weight of amine in total weight O of the solution.

Preferably the pre-treatment agent is applied to the shellfish and/or farming equipment (apparatus) at a concentration between 0.5 and 5 gpl.

The solvent of the pre-treatment agent is suitably selected from water, primary or secondary alcohols such as ethanol, methanol, ethoxyethanol, propanol, isopropyl alcohol, butanol, tertiary butanol and secondary butanol.

The pre-treatment agent is prepared by charging a mixing vessel with the solvent, heating if necessary to approximately 15-50 0 C, preferably approximately 25 0 C, and adding the amine or mixture of amines to make up the required concentration. Any suitable additives, for example, preservatives and further antimicrobial agents can be added. Advantageously, the amine acts as an antimicrobial agent.

The pH of the pre-treatment agent may require adjustment to a level tolerated by the shellfish, for example, approximately pH 4.5-8.5.

Antifouling composition The antifouling composition is used to repel unwanted organisms, crustaceans, weeds and generally any marine N \Melbourn\Cascs\Patent\6j000.61999\P6 1537AU. I\Specis'J61537. AU.I Specifcation 2008.4-1I doc 10 00 O fouling organisms. The antifouling composition generally Sacts as a physical barrier that provides resistance to the adherence of these unwanted fouling entities. However, at the same time, the antifouling composition does not damage the shellfish or restrict its growth.

The antifouling composition may also act to protect the ID shellfish from damage, for example, by attrition with other shellfish or against farming equipment.

00 There are several advantages resulting from the present invention. A major advantage is the time saving and resultant cost saving feature of reducing the frequency of cleaning and the potential of avoiding cleaning altogether. In the specific case of oyster culturing, where growth of a pearl is being nurtured, there is a significant further advantage. The reduction in handling of the growing oyster means that the chance of the growing pearl being dislodged from its position in the shell is reduced and therefore the likelihood of producing a lower quality pearl is reduced also. The increased chances of producing a pearl of high quality, and consequently increased value, is a significant advantage.

The antifouling composition of one embodiment comprises microcrystalline wax, paraffin wax and natural hydrocarbon wax.

The natural hydrocarbon wax preferably comprises naturally occurring waxes, for example beeswax and waxes derived from vegetable oils, for example soy wax.

Preferably the natural hydrocarbon wax comprises a combination of beeswax and soy wax.

Preferably, the natural hydrocarbon wax has a melting point of 51-65 0 C most preferably 55C. The preferred amount N \Melbourne\Cases\Paten\6 1000-6i99961 537AU I\SpecisP61 S3AU.I Specificaion 2008-411 doc 11 00 0 of soy wax in the embodiment is between 10% and 60%, most Spreferably between 12% and 25% of the total weight of the antifouling composition.

Preferably, the beeswax is of light colour with a melting point of 60-70 0 C, preferably 65 0 C. The acid value of the beeswax is a maximum of 25. The preferred amount of ND beeswax in the embodiment is between 5% and 50%, most Spreferably 5% and 25% of the total weight of the 00 10 antifouling composition.

c The microcrystalline wax comprises high molecular weight aliphatic hydrocarbons.

The microcrystalline wax preferably has an oil content between 2-10%, further preferably most preferably 3%.

The microcrystalline wax preferably has a melting point between 40 0 C and 80 0 C, further preferably between 50 0 C and 0 C, most preferably 60 0

C.

The microcrystalline wax preferably has a flash point between 200 0 C and 300 0 C, further preferably between 240 0

C

and 280 0 C, even more preferably between 260 0 C and 270 0 C and most preferably 266 0

C.

In one embodiment, the microcrystalline wax is utilised in the antifouling composition in an amount between 40% and 80%, preferably between 50% and 70%, further preferably about 60% by weight relative to the total weight of the composition.

The paraffin wax is suitably a fully refined petroleum hydrocarbon wax.

The paraffin wax preferably has an oil content less than N \Melbourne\Case\Paienk6I OOO61999\P6 537 AU I\Spmcis\P61537.AU. I Spccificason 2008-4-11 doc 12 00 further preferably between 0.01 and most preferably between 0.1 and 0.4%.

The paraffin wax has a melting point between 40 0 C and further preferably between 50 0 C and 70 0 C, most preferably 0

C.

IND In one embodiment, the paraffin wax is utilised in the 0 antifouling composition in an amount between 10% and O0 10 preferably between 20% and 40%, further preferably about O 30% by weight relative to the total weight of the (C composition.

The antifouling composition preferably further comprises an adhesion promoter.

The adhesion promoter preferably comprises a rosin ester.

The adhesion promoter preferably has a melting point between 70 0 C and 150 0 C, further preferably between 80 0 C and 120 0 C, most preferably between 95-100 0

C.

The adhesion promoter preferably has a maximum acid value of In one embodiment, the adhesion promoter is utilised in the antifouling composition in an amount between 1% and preferably between 2% and further preferably between 4% and 5% by weight relative to the total weight of the composition.

The antifouling composition comprising a natural hydrocarbon wax, microcrystalline wax, paraffin wax optionally includes further additives or compounds. The further additives or compounds may include ultraviolet absorbers, coloring agents and antimicrobial agents, as examples.

N \Melbourne\Cases\Patcnt\61000-61999\P61537AU. 1\Specis\P61 537AU I Specificalion 2008-4-11 doc 13 00 0 oo

C

One suitable additional compound is an antimicrobial agent or compound. One suitable antimicrobial agents is derived from organic citrus fruits such as D-Limonen. When present, the UV absorber is suitably present in an amount between 0.01% to preferably between 0.05% to such as 0.1% to or about 0.2% by weight relative to the total weight of the composition.

In one embodiment, the amount of antifouling composition deposited on the shell results in a wax thickness between 0.8-1.2mm. If the thickness is too great, the wax may lift from the shell more easily. However, in general the thickness of the wax does not affect the opening of the shell or the ability of the shellfish to breathe or feed.

Examples The invention will now be described in detail by way of reference only to the following non-limiting examples.

Example 1: Process for preparing the antifouling composition.

PARTS/WEIGHT

INGREDIENT FORMULA 1 FORMULA 2 FORMULA 3 Beeswax 9.7 10.7 3.2 Soy wax 15.0 20.0 25.0 Paraffin wax 40.0 50.0 60.0 Microcrystalline 30.0 10.0 wax Adhesion 5.0 8.0 10.0 promoter D-Limonene 1.0 UV Absorber 0.2 0.2 0.2 Oil soluble dye 0.1 0.1 0.1 .Mlburn\Cs\Pacnt\61000-61999\P A P6137AUI Spvciirlion 2008-4-11 doc 14 00

O<

SPrepare adhesion promoter as a solution of rosin ester Sparts) or terpene resin and white oil (mineral oil) parts) at 80 0 C minimum. The amounts can be 40 parts rosin: s 60 parts mineral oil.

Charge mixing vessel with, natural waxes, microcrystalline IND wax and paraffin wax. The total wax component amounts to 0 about 90% and adhesion promoter solution, about 9-10%.

00 Heat to 60'C and mix until homogenous.

Add about 0.2% UV absorber, and mix until dissolved.

Add about 0.05 0.1% oil soluble dye and mix until dissolved. Check shade. The shade required will be different for different wax application seasons. In general, the colour will be bright and visible so that lost shells may be located on the seabed. Pour molten product into cooling trays. Cooling may take several hours, but this depends on the thickness of the prepared wax blocks. Wax may be formed as chips, flakes or tablets if required.

Example 2: Process for preparing the pre-treatment agent in solution.

INGREDIENT PARTS BY WEIGHT Tallow Amine Acetate 10.0 White Oil Methanol 98% 15.0 Water 40'C 73.0 Acetic Acid 90% For pH adjustment Charge mixing vessel with Tallow Amine Acetate and heat to 40°C. Add approximately 2-4% paraffin oil and primary N \Melbourne\Cascs\Paient\61 000.61999P61]37A U I\SpecisP6S37 AU. I Specificaion 2008-4-1I doc 15 00 0 aliphatic alcohol (about 15-25% methanol or ethanol), make Sup to 100% with water at approximately 40 0

C.

The pre-treatment agent is prepared by dissolving the amine salt in a suitable alcohol solvent at 30 0 C followed by addition of antimicrobial agents dissolved in paraffin oil, the mixture is then diluted with water into a stable D concentrate at pH of 4.5-4.8.

OO 10 The above concentrate can then be diluted with water in a O ratio of 400 part water to 1 part concentrate, preferably A1 200 parts water and 1 part of concentrate. This dilution comprises the actual concentration of pre-treatment agent that contacts the shellfish.

Example 3: Process of treating shellfish.

Remove shells from aquatic environment and chip and clean to remove unwanted organisms, crustaceans and weeds.

Spray or dip shells and shell holding panel in solution of pre-treatment agent.

Blow with air and/or drain shells (preferably with gentle air blow) for approximately 1 minute.

Drain shells for approximately 1 minute.

Tap shells to ensure they are closed.

Quickly immerse shells and panel in antifouling composition at 50 0 C 58 0 C until covered and remove shells.

Immediately immerse shells and panel in seawater to cool and solidify the antifouling composition.

Replace shells and holding panels back in the aquatic environment.

The process may be repeated following a period of time.

During following applications, due to the inhibition effect of the composition applied, it may not be necessary for chipping and cleaning to take place, or at a minimum the amount of chipping or cleaning required is greatly N \eIbourne\Cass\Palent\61000-61999\P6)537AU I\Specis\P61537.AU I Specification 2008.4-1 doc 16 00 reduced.

(N

It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention.

In the claims which follow and in the preceding \D description of the invention, except where the context Srequires otherwise due to express language or necessary 0 10 implication, the word "comprise" or variations such as S"comprises" or "comprising" is used in an inclusive sense, Cl i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

N\Melbourne\Cases\Patent61OO-61999\P6I537.AU I\Spccis\P61S37A U.I Specification 2008-4-11 doc

Claims

1. A process for reducing or inhibiting the fouling of marine or aquatic shellfish or equipment used in the farming of marine or aquatic shellfish, comprising the steps of: I\O contacting shellfish or equipment with a pre-treatment agent, and treating the shellfish or equipment with an antifouling O composition.

2. The process of claim 1, wherein the contacting of the shellfish or equipment with the pre-treatment agent comprises painting, spraying, electrostatic spraying, brushing and/or dipping the shellfish or equipment with or into the pre-treatment agent.

3. The process of claim 2, comprising air blowing the shellfish or equipment following contact with the pre- treatment agent.

4. The process of any one of claims 1 to 3, wherein the step of treating the shellfish or equipment with the antifouling composition takes place within 3 minutes following contacting with the pre-treatment agent. The process of any one of claims 1 to 4, wherein the pre-treatment agent comprises an amine.

6. The process of claim 5, wherein the amine is an amine salt.

7. The process of claim 6, wherein the amine is an organic acid salt of an amine.

8. The process of any one of claims 5 to 7, wherein the N Welbourne\Cascs\Patent\61000-61999\P61537 AU, I'Spccis\P61537A U, I Specificaton 2008-4-11 doc 18 00 amine is a fatty acid amine with a carbon chain length within the range of C6 C 24

9. The process of any one of claims 5 to 8, wherein the amine is tallow amine or an organic acid salt thereof. The process of any one of the preceding claims, I\D wherein the pre-treatment agent is contacted with the Sshellfish or equipment in solution form at a concentration 0 10 between 2-20% by weight. 0 C1 11. The process of any one of the preceding claims, wherein the pre-treatment agent is contacted with the shellfish or equipment in solution form at a concentration between 0.5 and 5 gpl.

12. The process of claim 10 or claim 11, wherein the pH of the pre-treatment agent is between about pH 4.5-8.5.

13. The process of any one of the preceding claims, wherein the step of treating the shellfish or equipment with the antifouling composition comprises coating or dipped the shellfish or equipment into the antifouling composition.

14. The process of any one of the preceding claims, wherein the step of treating the shellfish or equipment with the antifouling composition comprises contacting, coating or dipping the shellfish with or into the antifouling composition at an antifouling composition temperature of between 40 0 C and 70 0 C. The process of any one of the preceding claims, comprising cooling the shellfish or equipment following treatment with the antifouling composition before returning the shellfish or equipment to the marine or aquatic environment. N:\Melbourne\Cases\Patcnt\61000-61999\P61537AU I\SpemisP6I1537AU. I Specificalion 2008-4.11 doc 19 00 O0

16. The process of claim 15, wherein the cooling step 3 comprises spraying or otherwise contacting the shellfish or equipment with water sourced from the natural marine or aquatic environment of the shellfish.

17. The process of any one of the preceding claims, IND wherein the antifouling composition comprises 0 microcrystalline wax, paraffin wax and natural hydrocarbon 00 10 wax. C( 18. The process of claim 17, wherein the natural hydrocarbon wax comprises soy wax in an about of between and 60% by weight of the antifouling composition, and beeswax in an amount of between 5% and 50% by weight of the antifouling composition.

19. The process of claim 17 or claim 18, wherein the amount of microcrystalline wax in the antifouling composition is between 40% and 80% by weight of the antifouling composition. The process of any one of claims 17 to 19, wherein the amount of paraffin wax in the antifouling composition is between 10% and 50% by weight relative of the antifouling composition.

21. The process of any one of claims 17 to 20, wherein the antifouling composition comprises one or more agents selected from adhesion promoters, antimicrobial agents, UV absorbers, colours and dyes.

22. The process of claim 21, wherein the antifouling composition comprises an adhesion promoter which is a rosin ester.

24. The process of any one of claims 17 to 23, wherein N: We bourn\Cases\Paenz\61O0O-61999\P61 537 AU I\Specis\P6I 537.AU.I Specification 2008-4.11 doc 20 00 the antifouling composition comprises an antimicrobial agent, which is D-Limonen. The process of any one of the preceding claims, wherein the step of treating the shellfish or equipment comprises depositing a layer of the antifouling composition on the shell at a thickness of between 0.8- \O 1.2mm. 00 10 26. The process of any one of the preceding claims, Scomprising repeating the process steps of: CAl contacting shellfish or equipment with a pre-treatment agent, and treating the shellfish or equipment with an antifouling composition, not less than 3 months following the first application of the process steps.

27. A multi-component composition for reducing or inhibiting the fouling of marine or aquatic shellfish or equipment, the composition comprising a first component which is a pre-treatment agent and a second component which is an antifouling composition, wherein in use the first and second components are applied sequentially to marine or aquatic shellfish to reduce or inhibit fouling of the shellfish.

28. The multi-component composition of claim 27, wherein the pre-treatment agent is as defined in any one of claims 5 to 12, and wherein the antifouling composition is as defined in any one of claims 17 to 24.

29. A process for reducing or inhibiting the fouling of marine or aquatic shellfish or equipment used in the farming of marine or aquatic shellfish, or a multi- component composition for reducing or inhibiting the fouling of marine or aquatic shellfish or equipment, N:\Mlclbourne\Cases\Patent\61000-61999\P6537AU I\Specis\P6IS37AU I Specification 2008-4-1 1 doc 21 00 0 substantially has herein described with reference to the Examples. 00 N \Melbourne\Cases\Patent\610OO-6 999\1i6i 37.A U. I \Specis\P6i 537 AU. I Specifiat ion 2008-4-11 doc