GB2061081A - Shellfish culture - Google Patents

Abstract

A mounting device for use in shellfish culture is provided in which the device (2 or 200) is adapted to be attached to an elongate member such as durable plastic tape (1) and is provided with a base (23 or 203) adapted to be secured by adhesive (3) to the shell of a shellfish, e.g. an oyster (0). Attachment of the device to the tape (1) may be by means of a cross piece (21) inserted through and turned across a slot (10) in the tape (1) or the device is provided with barbs (212) for insertion through an opening (10) in the tape (1) for retentive contact with the latter. In a still further form the device consists of a clip (200) having limbs (202) which are bent about the tape (1), the base (203) of the clip being secured by adhesive (3) to the shell of the oyster (0). <IMAGE>

Description

SPECIFICATION Shellfish culture This invention has reference to the culture of shellfish especially oysters but also including scallops, clams, molluscs and the iike wherein the shellfish are located or mounted in spaced apart relationship for submerging in water so that culture or cultivation of the shellfish can take place under optimum conditions, e.g. for large quantity production of high protein food.

The object of the present invention is to basically provide mounting devices for the shellfish and also to further provide location means for the mounted shellfish during culture (and which is also suitable fortheirgeneral handling and subsequent supply).

Practical advantages of the invention in these respects will be apparent from the following disclosure: According to one aspect of the invention a mounting device for use in underwater shellfish culture is characterised by a part of the device adapted to be attached to an elongate member such as durable tape and having a base part adapted to be adhesively secured to a shellfish.

According to a further aspect of the invention location means for underwater shellfish culture comprises at least one elongate member and a plurality of the aforesaid mounting devices for spaced apart attachment to the elongate member, each said mounting device being adapted to be adhesively secured to a corresponding shellfish whereby the latter can be mounted on the elongate member in spaced apart relationship.

Referring to the drawings and as applied to the culture of oysters, the procedure is as follows, in which: FIGURES 1 & 2 are perspective views of one form of the location means respectively showing an oyster in the detached and attached condition in relation to an elongate member or tape.

FIGURES 3 to 6 are enlarged scale detail plan, underside plan, side elevation and cross sectional views respectively of the mounting device shown in FIGURES 1 & 2, FIGURE 6 being a section taken on the line VI-VI of FIGURE 3.

FIGURES 7 & 8 are perspective views similar to FIGURES 1 & 2 showing an alternative mounting device.

FIGURES 9 & 10 are plan and side views respectively in detail of the mounting device shown in FIG URES 7 & 8 and on an enlarged scale, and FIGURES 11 & 12 are perspective views similar to FIGURES 1 & 2 but showing a further alternative mounting device.

Like parts are referred to by the same or similar reference designation whilst dimensions or other values quoted herein are given by way of practical example only and may be varied according to requirements. Modification and different modes of use of the location means are subsequently described.

Referring to FIGURES 1 & 2 the elongate member or substrate is shown consisting of flexible tape 1 of plastic material such as that commercially available for packing purposes and, for example, may be 9mm wide and 1 mm thick.

The tape 1 is provided with a series of holes 10 spaced apart along the tape in preferably a regular manner according to required spacing of oysters 0 on the tape.

In the example shown each hole 10 is of rectangular or slot form in the lengthwise direction of the tape 1 and for mounting an oyster 0 on the latter receives engaged with the slot 10 the stem 20 of a mounting device 2 which is adhesively secured at 3 to the shell of the oyster. For secure retentive engagement the stem 20 of the device is provided with a head in the form of a cross piece 21 having end flanges or ribs 210. Thus on the cross piece 21 being aligned with a slot 10 in the tape 1 and inserted through it and then turned through a right angle, the end ribs 210 of the cross piece 21 locate against the edges of the tape 1 (FIGURE 2). On such engagement that part of the tape 1 at the slot 10 is then positioned between the cross piece 21 and an intermediate bearing member or disc 22 on the stem 20.

The other end of the stem 20 is provided with a base 23 for adhesive securing to the shell of an oyster 0 and as will be seen more clearly in FIGURES 3 to 6, the base is gapped at 231 and also apertured at 230 whereby the adhesive 3 can have an overlapping or interlocking engagement with the base 23 as well as adhesive contact.

A suitable adhesive consists of thixotropic epoxy resin preferably containing a fast curing agent and powder additives. The consistency of the adhesive should be such that it can be applied as a "blob" to an oyster shell for direct adhesive contact with the latter and prior to setting receives pressed into it the base 23 of a mounting device 2 whereby the adhesive 3 mainly or largely overlaps or envelopes the base 23 for interlocking engagement therewith on setting ofthe adhesive.

The adhesive 3 should also be capable of application in a workable condition to the shell of an oyster Oat a low temperature which will not damage the shell or oyster, e.g. preferably not in excess of 24 C (80"F).

In an alternative arrangement of mounting device shown in FIGURES 7 & 8, and in detail in FIGURES 9 & 10 the head 211 of the device 2 is such that a barb-like retentive engagement is obtained with the tape 1 and in the example shown the head provides a pair of oppositely arranged barbs 212 alongside the stem20 which barbs, as the head 211 and stem 20 are pushed through a hole or slot 10 in the tape 1, are temporarily contracted towards the stem 20 and then expand beyond the extent ofthe hole or slot 10 to bear against the adjacent side of the tape 1.As in the case of the arrangement shown in FIGURES 1 & BR< 2, an intermediate bearing member or disc 22 is shown provided for obtaining firm attachment to the The drawing(s) originally filed was/were informal and the print here reproduced is taken from a later filed formal copy.

tape 1 whilst the base 23 is preferably also of similar form for interlocking engagement with the adhesive 3 on the shell ofthe oyster 0. Either of the mounting devices 2 may be moulded in plastic material.

In the further alternative arrangement shown in FIGURES 11 & 12 the mounting device consists of a clip 200, the base 203 of which is adhesively secured to the oyster shell and is preferably interlockingly engaged by the adhesive 3, whilst the lugs 202 of the clip 200 are bent over the edges of the tape 1 and against the opposite side of the latter. In addition to its simplicity this arrangement has the advantage that perforation of the tape 1 is not necessary.

In any of the arrangements herein described the oysters 0 can be carried by the tape 1 facing in opposite directions in an alternating manner for balance support by the tape.

During oyster culture a large number of tapes 1 can be suspended vertically underwater in the sea or a river estuary, i.e. by suspension from supporting structure which may be of a fixed nature such as a pier or may consist of flotation means such as one or more rafts or similar floating support. Thus a series of tapes may be suspended from crossbars of the supporting structure orflotation means or the tapes may be strung back and forth in frames which in turn are removably carried by the supporting structure or flotation means, either arrangement permitting groups of oysters to be raised for inspection and return to their underwater location or removed as appropriate.

Each tape 1 is of adequate strength and durability for supporting a considerable number of oysters whilst the secure attach ment provided. by the mounting devices 2 enables the oysters to be located underwater for a prolonged period and in a spaced apart arrangement for cultivation under optimum conditions as regards feeding and growth and also safety from seabed or riverbed predators. Furthermore, the flexibility of the tape enables the oysters to yield with tidal or current flow or other relative movement of the surrounding water.

Instead of suspension of the elongate members or tapes 1, they may be alternatively or additionally laid at the bottom of the sea or river or on a foreshore according to the species of shellfish being cultivated and its environmental requirements. This applies particularly in the case of clams and also to oysters once the latter are large enough to resist attack from most predators.

Whether for suspension or bottom laying, the elongate members or substrates may be of other suitable form or cross section for engagement by the mounting device 2.

After culture and for ease of handling the oysters O can be supplied in suitable quantities still mounted on lengths of tape 1, e.g. in frames, the detachable mounting afforded readily enabling any dead or unsuitable oysters to be removed and replaced in maintaining the required quality and quantity of the oysters supplied.

The frames in which the tape mounted oysters are strung may be of rectangular or other suitable form and may be connected or assembled as a cubic or similar structure for holding a considerable number of suspended oysters in a compact manner.

In a typical arrangement metal frames of H-form are secured at their extremities by corner rods to provide a cubic assembly with the tapes strung between the limbs of the frames parallel to the centre bars of the latter. Such an assembly of no more than a cubic metre is capable of accommodating some five hundred mature oysters.

The frame assemblies can be readily handled and treated, e.g. by chemical spraying to remove any undesired settlements. They can also withstand very rough weather when suspended or otherwise located in the sea or in similar exposed conditions or alternatively can be used in shallow water, e.g.

barely a metre deep.

As will be appreciated from the foregoing, location means and mounting devices thereof according to this invention for use in the culture of shellfish are of an extremely simple and inexpensive nature and can be used on a throw away basis. Furthermore, the mounting of the oysters or other shellfish on the elongate members or tapes can be rapidly carried out at a high production rate of elongate members or tapes complete with oysters or the like mounted thereon.

It is to be understood that this invention includes within its scope not only the location means provided by the elongate members or tapes and mounting devices, but also the mounting devicesthem- selves for use therewith.

Claims (13)

1. A mounting device for use in underwater shellfish culture characterised by a part of the device adapted to be attached to an elongate member such as durable tape and having a base part adapted to be adhesively secured to a shellfish.

2. A mounting device according to claim 1 wherein the device is adapted to have a detachable attachment with the elongate member.

3. A mounting device according to claim 1 or 2 wherein the mounting device is provided with means for engaging an opening therefor in the elongate member.

4. A mounting device according to claims 1 and 3 or claims 1,2 and 3 wherein the said engaging means is secured to the base part of the device by a stem.

5. A mounting device according to claims 3 and 4 wherein the said engaging means consists of a cross piece provided on the stem and arranged to be inserted through a slot therefor in the elongate member and then turned crosswise relative to the slot for retention of the mounting device on the elongate member.

6. A mounting device according to claims 3 and 4 wherein the said engaging means consists of one or bore barbs provided on the stem and arranged to be inserted through an opening therefor in the elongate member for retentive contact with the latter.

7. A mounting device according to any ofthe preceding claims wherein the base part of the device is apertured and/or gapped for interlocking engagement with adhesive applied thereto and to a shellfish.

8. A mounting device according to claim 1 or 2 wherein the device is in the form of a clip having limbs adapted to be closed about the elongate member, a base part of the clip being adapted to be adhesively secured to a shellfish.

9. A mounting device for use in underwater shellfish culture when substantially as herein described with reference to FIGURES 1 to 6 or FIG URES 7 and 8 or FIGURES 9 and 10 or FIGURES 11 and 12 of the accompanying drawings.

10. Location means for underwater shellfish culture comprising at least one elongate member and a plurality of mounting devices according to any of the preceding claims for spaced apart attachment to the elongate member each said mounting device being adapted to be adhesively secured to a corresponding shellfish whereby the latter can be mounted on the elongate member in spaced apart relationship.

11. Location means according to claim 10 wherein the or each elongate member consists of durable tape, e.g. of plastics material.

12. Location means according to claim 10 or 11 wherein in use each mounting device is secured to a corresponding shellfish by means of adhesive consisting basically of a thixotropic epoxy resin containing a curing agent.

13. Location means for underwater shellfish culture substantially as herein described with reference to the accompanying drawings.