AU2003200570A1 - Improvements in crab production - Google Patents

Description

3551A

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicants: KEITH WALLACE PAINTER and CLISEL PTY LTD Actual Inventor: KEITH WALLACE PAINTER Address for Service: HODGKINSON OLD McINNES Patent and Trade Mark Attorneys Level 3, 20 Alfred Street MILSONS POINT NSW 2061 Invention Title: "IMPROVEMENTS IN CRAB PRODUCTION" Details of Associated Provisional Application: PS 0621 filed 19 February 2002 The following statement is a full description of this invention, including the best method of performing it known to us: FIELD OF INVENTION The present invention relates to an automated or semi-automated crab production facility.

More specifically, the invention provides a system for crab farming or crab production based on using crablets from a hatchery and growing them out to market size in a mechanised computer-controlled facility.

BACKGROUND OF THE INVENTION Traditional methods of farming and/or harvesting crabs are not very efficient, and are highly labour intensive. Increasing demand for crabs and for crabmeat has resulted in higher prices and often unsatisfied demand. Accordingly, there is a need to provide means for the more efficient farming and harvesting of crabs which is capable of operating all year round to provide a continuous supply of crabs and/or processed crabs to the market.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of this invention to provide a system for the farming and harvesting of crabs, including both soft-shell and hard-shell crabs, which goes at least some way towards overcoming or at least minimising the problems or limitations of previously known systems and methods for farming and harvesting of crabs, or at least providing a clear alternative choice for crab farmers or producers.

This and other objects of the invention will become more apparent from the following description and drawings.

According to one aspect of the invention there is provided an apparatus for the commercial production or farming of crabs, comprising a water trough having a plurality of compartments each adapted to contain one or more crablets or crabs, a movable gantry frame straddling said trough transversely or laterally from one side to the opposite side and adapted to move longitudinally in relation thereto, a central processor operatively connected to said gantry to monitor or to control one or more activities in or associated with each compartment whereby the central processor may be programmed to add material to or remove material from the or each compartment, or to identify features associated with the growth or life cycle of each crab.

According to another aspect of the invention there is provided a method for the commercial production or farming of crabs, wherein crablets are contained in apparatus of the type described herein, and are fed, maintained and monitored throughout their growth or life cycle in the apparatus until required for harvesting or processing.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS One non-limiting embodiment of the present invention will now be described with reference to the drawings in which:- FIG. 1 is a top or aerial perspective view of a preferred system for the farming and harvesting of crabs; and FIG. 2 is a cross-sectional view of the gantry-mounted auto-feed facility of the crab farming and harvesting system of Fig. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT According to this embodiment, the system 1 for the farming and harvesting of crabs comprises a pair of concrete troughs 2 having a plurality of removable trays 3 to contain the crabs. An auto feeder unit 4 comprises a motorised gantry frame which straddles the twin trough units 2 and is mounted on a pair of angle rails 5 set into the trough foundations 6, which is continuous along the full length of the individual trough banks 2.

A control board 7 is mounted on top of the auto feeder unit, which is driven by variablespeed motors along the rails An optical drive is interlinked directly to the drive motors to provide counting pulses to various segments of the system.

A bar code reader or other device identifies the start of each tray compartment and reports the compartment number to a meter mounted on the control cabinet. It also provides compartment number data to the control computer, and further when interlinked to the optical drive and the feeder-rate switch, allows different quantities of feed to be released to each compartment.

A fixed feed hopper 8 carrying sufficient feed for a run of the feeder is mounted on the rear of the frame. The feed hopper extends across a number of troughs (typically two or more) and a number of outlets 9 (typically 14 or more) fixed to the feed hopper base.

Hopper outlets 9 consisting of solenoid outlet packs are mounted on the feeder hopper base and allow feed to be discharged to the tray compartments The solenoid operating circuit is tied into the feeder switch (which can be manually operated) mounted on the control cabinet and the optical drive and compartment reader to govern the amount of feed discharged to each compartment.

The auto feeder 4 is capable of manual and automatic operation by switch over controls, on the control cabinet.

Under automatic control signals are received by the computer from the opto-interrogator, speed controller, identification circuits and compartment camera. The inbuilt software analyses the information and allows the computer to identify:individual crab growth, moult stage, residual feed, crab death, residual carapace, and crab weight.

When soft shell crabs are being produced, the software alerts for possible harvest when harvesting is imminent. A "prior warning" pulse is sent from the computer to the harvesting operator board to identify location. On detection of actual moult a "to harvest signal" is sent to the harvest board and harvesting effected through the use of a pump harvester.

Cameras are adjusted for "standard field and compartment floor cover and light intensity".

In addition each camera has its own light source giving standard illumination.

When hard shell crabs are being produced, the detection of moult stage is by-passed.

The control board on the control console has a set of LEDs attached to each feeder solenoid which indicate when the solenoid is activated, thus allowing continuous visual monitoring of feeder activity. An initial feed cycle can be activated where necessary to prove the feed cycle.

The control board is fitted with controls to all individual compartments viewed by the camera; the resultant picture can be displayed on the computer video screen.

Where necessary movement of the feeder can be interrupted for closer examination of all operations.

The feeder can be used in harvest mode with the feeder supply turned off, thus allowing the unit to be used during non-feeding periods.

Maintenance can be carried out with the feeder being backed off the trough segments allowing full access to all on board equipment.

The troughs 2 that carry the crablets during the growing phase are typically six metres long by one metre wide (internal) and some 250 mm deep. Troughs carry the recycled water in which the crabs live and are usually limited in length for risk reduction purposes.

In the preferred embodiment, troughs 2 are mounted side by side in a bank. Banks of troughs run longitudinally to a length required to meet the production requirements. The required production level is met by running other trough banks parallel to the original set separated at a distance dictated by the enclosure framing column spacings.

The troughs are preferably manufactured from internally coated (epoxy) prestressed concrete or from fibreglass. When used in a multilevel mode weight usually precludes the use of concrete.

Removable trays 3 fitted with flow-through separators are used to form individual compartments within the trough. Trays are formed from a suitable plastic, such as polyethylene, polypropylene and recycled plastics.

Tray compartments 10 are the individual segments that house a crab (to prevent crab cannibalism). They are adjustable to hold various crab sizes as they grow to market weight.

The system is ideally used in regions where water temperatures are suitable to the crab growth, and sufficient land is available at reasonable prices to support this form of grow out.

Where temperatures are lower than ideal and controlled environments are required or land prices are excessive, then a different form of facility is preferred. In these instances, there are some differences in equipment requirement, particularly the auto feeder that although operating in a similar fashion takes a form more suitable to multi level use.

Input water for the system is drawn from a suitable source at a salinity level to suit the crabs being raised (normally 28,000 ppm to 34,000 ppm). Where the quality of the feed water is suspect due to unsatisfactory levels of pollutants, the water source may need to be changed or if this is not possible full pre-treatment of the input water must be used.

Water from the trough drainage system contains detritus and organic solutes that require treatment before it can be returned to the system. Where some water (after primary treatment) can be allowed to return to the initial water source then remediation systems can be significantly simplified.

Trough drainage water is led to a remediation pond. The pond is located and sized so as to allow sufficient algae growth to absorb the detritus and nitrates arising from the nitrification of the ammonia load from crab excreta. Often the pond can be stocked with a fish species such as mullet, which assists in the digestion of the solid detritus particles. Pond size and dynamics is site specific and directly related to the crab production levels.

Where some release of drainage water to the waterway is permissible to then nitrate levels will not build up to unacceptable levels and bio-filter system can be used. It can either be of the "drowned type" or "top fed vertical" filter systems.

Drowned type systems are normally very effective but require significant quantities of air to induce water circulation through the filter. This may not be disadvantageous as oxygensaturated water is required for input to the troughs.

Particulate filtration is mandatory downstream from the bio-remediation ponds or the alternative bio-filter system irrespective of which method is adopted. After filtration the recycled water is passed through a sterilisation phase that can be direct ozone treatment, UV sterilisation, or a combination of both. The sterilisation phase is production dependent and dictates the method to be adopted.

In the preferred embodiment, water is recirculated through the system, each trough being fed from a water inlet pipe fitted with a manually controlled ball valve controlling water flow through the trough. An outlet drainage pipe fitted with a notch to enable assessment of water flow rates sets heights of water within the trough. Water flow from the outlet standpipe is returned to the trough drainage system and then to the water treatment system.

In order to establish the minimum acceptable water flow rates, it is necessary to know the saturated oxygen content of the water within the troughs. Probe type 02 meters are carried on the feeder and a data logger assesses and stores the information in the on-board computer. Where out of range conditions exists, audio visual warning is provided for operator attention. Monitoring of ammonia levels is not normally necessary as the water is treated when it passes through the water treatment segment of the recycling phase.

Crabs are harvested when they reach the desired size. Crabs are extracted from the appropriate compartment using a pump extraction system. The feeder has a drainable bucket into which harvested crabs are received and they are then taken to the process area for further handling.

In the preferred system according to the invention, the process area accepts the harvested crab and prepares it for freezing. Preparation consists of removal of some appendages. The crab is frozen using liquid nitrogen and transferred to the packaging area. Packaging is in a vacuum pack (normally 10 to 12 crabs per pack). The frozen pack is then held in store for future despatch.

The system of the preferred embodiment is basically a single level operation, the foundation requirements are only those needed to carry trough weights and the individual columns supporting the covering structure. As the weights involved are quite low, complicated foundations are not required. The trough foundations are usually interlinked to a central drain for elimination of any on site water flow and for the drainage of any roof stormwater; the same foundation is used to carry the rails on which the auto feeder is run.

The interspace between trough banks is not normally paved, except with crushed brick or gravel.

Covering of the facility is either in lightweight plastic or heavy shade cloth. Lightweight plastic is used where some degree of water temperature rise is desired during the winter months. Shade cloth can be used where temperature elevation is not needed and can be arranged in such a fashion as to discharge rainwater to fixed roof outlets.

Where summer months conditions require it the side wall of the covering can be rolled up to allow free air movement.

Although an exemplary embodiment of the invention has been shown and described, it will be apparent to those having ordinary skills in the art that changes, modifications or alterations to the invention described herein may be made without departing from the spirit of the present invention. All such changes, modifications and alterations should therefore be seen as being within the scope of the present invention.

It should be apparent that the present invention provides a substantial advance in the field of commercial crab production, providing all of the herein-described advantages without incurring any relative disadvantages.

The term "comprising" as used herein is used in the inclusive sense of "having" or "including" and not in the exclusive sense of "consisting only of".

Claims (14)

1. Apparatus for the commercial production or fannrming of crabs, comprising a water trough having a plurality of compartments each adapted to contain one or more crablets or crabs, a movable gantry frame straddling said trough transversely or laterally from one side to the opposite side and adapted to move longitudinally in relation thereto, a central processor operatively connected to said gantry to monitor or to control one or more activities in or associated with each compartment whereby the central processor may be programmed to add material to or remove material from the or each compartment, or to identify features associated with the growth or life cycle of each crab.

2. Apparatus according to claim 1, wherein the central processor can be programmed to provide means for the addition of feed material to promote growth of individual crablets or crabs.

3. Apparatus according to claim 1, wherein the central processor can be programmed for to provide means for the removal of residual carapace.

4. Apparatus according to claim 1, wherein the central processor can be processed to recognise moult stage, changes in crab weight or crab death.

Apparatus according to any one of the preceding claims wherein the gantry is motorised by means of variable speed motors.

6. Apparatus according to any one of the preceding claims, further including an optical drive interlinked to the drive mechanism of the gantry.

7. Apparatus according to any one of claims 1 to 6, wherein the or each trough contains removable baskets to provide the plurality of compartments each adapted to contain one or more crablets or crabs.

8. Apparatus according to claim 7, wherein the capacity of the baskets is adjustable to hold various crab sizes as they grow to market weight.

9. Apparatus according to any one of the preceding claims, wherein the gantry includes one or more feedstuff hoppers with one or more closable outlets for directing feedstuff to the individual compartments.

Apparatus according to claim 9, wherein the outlets are closable by solenoid means.

11. A method for the commercial production or farming of crabs, wherein crablets are contained in apparatus of the type defined in any one of claims 1 to 10, and are fed, maintained and monitored throughout their growth or life cycle in said apparatus until required for harvesting and/or processing.

12. A method for the commercial production of crabs according to claim 11 for the production of soft shell crabs, including means for detection of moult stage in the crab growth cycle.

13. A method for the commercial production of crabs according to claim 11 for the production of hard shell crabs, wherein the detection of moult stage is by-passed.

14. Apparatus for the commercial production or farming of crabs as claimed in any one of claims 1 to 10, substantially as hereinbefore described and illustrated. A method for the commercial production or farming of crabs as claimed in any one of claims 11 to 13, substantially as hereinbefore described and illustrated. Dated this 19 th day of February 2003 KEITH WALLACE PAINTER and CLISEL PT LTD HODGKINSON OLD McINNES Patent Attorneys for the Applicants