Environmental DNA sampling devices

Abstract

An environmental eDNA sampling filter device has a body to which a filter membrane can be secured by a retaining element in which flexing of a tab of the body causes the retaining element to be released from the body to release the filter membrane. This can be used to obtain eDNA samples from the environment or can be used with a funnel-type environmental eDNA sampling apparatus or an underwater environmental DNA sampling apparatus. A filter device may be removably mounted over an opening of either apparatus and removed for transport and analysis after obtaining a sample.

Description

[0001] Environmental DNA Sampling Devices

[0002] FIELD

[0003] This invention relates to methods and devices for the collection of environmental DNA (eDNA) samples from aquatic environments.

[0004] BACKGROUND

[0005] eDNA samples are collected for a variety of reasons including the identification of species in a particular location, what the biodiversity of the area is, and if any invasive or endangered species are present. eDNA collection requires the effective concentration and preservation of eDNA from aquatic environments until they can be analysed. The main scientific and technological uncertainties in the process are:

[0006] • Concentration Efficiency: Current methods for concentrating eDNA from large volumes of water are often inefficient, leading to loss of valuable genetic material or they require substantial time-effort and / or specialized equipment not always available or practical in remote locations.

[0007] • Cross-Contamination: Minimizing cross-contamination during eDNA sampling and processing is critical. Existing techniques are prone to contamination, which can compromise the integrity of the data.

[0008] • Integrity of eDNA Molecules: eDNA molecules are fragile and can degrade easily. Preserving the integrity of these molecules from the point of collection through to analysis is a major challenge.

[0009] Existing devices can pose sample contamination risks and be difficult and cumbersome to deploy.

[0010] It is an object of this invention to provide improved eDNA sampling devices and apparatus or to at least provide the public with a useful choice.SUMMARY

[0011] According to one example embodiment there is provided an environmental DNA sampling device comprising:

[0012] a. a body having a tab extending therefrom and a flow path therethrough; and

[0013] b. a retaining element configured to engage with the body so as to retain a filter membrane in the flow path,

[0014] wherein flexing of the tab causes the retaining element to be released from the body.

[0015] According to another example embodiment there is provided a method of processing an environmental DNA sample comprising:

[0016] a. obtaining an environmental DNA sample from an aqueous environment using a sampling filter unit having a removable filter membrane;

[0017] b. placing the sampling filter unit into an environmentally sealed container and preserving it until further laboratory processing using a DNA-suitable preservation method; and

[0018] c. removing the filter membrane from the sampling filter unit and processing it in laboratory conditions for environmental DNA extraction and analysis.

[0019] According to another example embodiment there is provided an environmental DNA sampling apparatus comprising:

[0020] a. a body defining a hollow internal region;

[0021] b. a port providing a flow path from the internal region; and

[0022] c. an opening into the internal region having a filter receiver adapted to removably receive a filter unit so that when the filter unit is received it covers the opening such that flow into the internal region must be through the filter unit.According to another example embodiment there is provided a method of environmental DNA sampling comprising:

[0023] a. inserting a filter unit into an environmental DNA sampling apparatus; b. drawing fluid out of the internal region through the port using a water pumping device so as to draw fluid into the internal region through the filter unit; and

[0024] c. removing the filter unit for storage and processing.

[0025] According to another example embodiment there is provided an underwater environmental DNA sampling apparatus comprising:

[0026] a. a body having an inlet and an outlet defining a fluid flow path through the device and a constricted region between the inlet and outlet;

[0027] b. one or more opening through the body from the constricted region utilising the Venturi effect to induce fluid flow through each opening; and c. a removable filter provided over each opening.

[0028] According to another example embodiment there is provided a method of environmental DNA sampling comprising:

[0029] a. inserting a filter device into an environmental DNA sampling apparatus; b. placing the apparatus into an aqueous medium and causing fluid to pass through the apparatus from the inlet to the outlet so as to draw fluid from the aqueous medium through the filter device; and

[0030] c. retrieving the apparatus and removing the filter device for processing.

[0031] Embodiments may be implemented according to any one of the dependent claims recited at the end of this specification.

[0032] It is acknowledged that the terms "comprise", "comprises" and "comprising" may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, these terms are intended to have an inclusive meaning - i.e., they will be taken to meanan inclusion of the listed components which the use directly references, and possibly also of other non-specified components or elements.

[0033] Reference to any document in this specification does not constitute an admission that it is prior art, validly combinable with other documents or that it forms part of the common general knowledge.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings which are incorporated in and constitute part of the specification, illustrate embodiments of the invention and, together with the general description of the invention given above, and the detailed description of embodiments given below, serve to explain the principles of the invention, in which:

[0036] Figure 1 shows a body and retaining element of an environmental sampling device according to one embodiment.

[0037] Figure 2 shows a filter membrane interposed between the body and retaining element of the environmental sampling device shown in Figure 1 before assembly.

[0038] Figure 3 shows a detailed view of interengaging features of the body and retaining element of the environmental sampling device shown in Figure 1.

[0039] Figure 4 shows a plan view of an assembled environmental sampling device using the body and retaining element shown in Figure 1.

[0040] Figure 5 shows a plan view of the retaining element shown in Figure 1.

[0041] Figure 6 shows an underside view of an assembled environmental sampling device using the body and retaining element shown in Figure 1.Figure 7 shows a top side perspective view of an eDNA sampling apparatus according to one example.

[0042] Figures shows a bottom side perspective view of the eDNA sampling apparatus shown in Figure 8.

[0043] Figure 9 shows a bottom perspective view of the eDNA sampling apparatus shown in Figure 8.

[0044] Figure 10 shows a top perspective view of the eDNA sampling apparatus shown in Figure 8.

[0045] Figure 11 shows a bottom side perspective view of an eDNA sampling apparatus according to one example.

[0046] Figure 12 shows a bottom top side perspective view of the eDNA sampling apparatus shown in Figure 11.

[0047] Figure 13 shows a top perspective view of the eDNA sampling apparatus shown in Figure 11.

[0048] Figure 14 shows a bottom perspective view of the eDNA sampling apparatus shown in Figure 11.

[0049] Figure 15A shows a perspective view of an eDNA sampling apparatus according to another example.

[0050] Figure 15B shows an eDNA pump sampling system including the eDNA sampling apparatus shown in Figure 11.

[0051] Figure 16 shows a perspective view of an underwater eDNA sampling apparatus.Figure 17 shows a cross-sectional view along the longitudinal axis of the underwater eDNA sampling apparatus shown in Figure 16.

[0052] Figure 18 shows a detailed view of a filter unit located within a filter receiver of the underwater eDNA sampling apparatus shown in Figure 16.

[0053] Figure 19 shows the underwater eDNA sampling apparatus of Figure 16 with a tether attached.

[0054] Figure 20 shows a perspective view of an underwater DNA sampling apparatus having control surfaces.

[0055] DETAILED DESCRIPTION

[0056] Figures 1 to 6 show an environmental DNA sampling device according to an example embodiment. Body 1 has a recess 2 dimensioned to seat and accommodate the retaining element 3. In this case the recess 2 and grill 4 are configured to support a filter membrane 5 whilst allowing a fluid to flow through a flow path defined between the grill bars 4. The device is assembled by arranging the body 1, retaining element 3 and filter membrane 5 as shown in Figure 2 and bringing the retaining element 3 into the recess 2 with the filter membrane sandwiched in-between as shown in Figure 4.

[0057] Interengaging features of the body 1 and retaining element 3 retain the parts together. As seen in Figures 3 and 5 retaining element 3 has projections in the form of ramps 6 on opposite sides of its periphery. These ramps engage in an annular recess 7 formed as an undercut in body 1. During assembly body 1 may be bent to allow the ramps 6 to located within the annular recess 7. To separate the parts body 1 may again be bent to allow the ramps 6 to be released from annular recess 7. Tab 8 provides a convenient means to handle the device without contaminating the filter membrane. Flexing the tab 8 is also a convenient way to release a ramp 6 from annular recess 7.The retaining element 3 and recess 2 may be of circular shape to accommodate standard filter membranes but could be other shapes. Filter membrane 5 may desirably have a pore size of between 5 -50 urn. Filter membrane 5 can be formed of nylon, glass fibre or polyethersulfone (PES) or other hydrophilic porous materials. Body 1 can be formed of a recycled or compostable plastic. Retaining element 3 can also be formed of a recycled or compostable plastic.

[0058] An environmental DNA sample can be obtained from an aqueous environment using a sampling filter unit in the form of the device described above having a removable filter membrane. The sampling filter unit may be preassembled in a sterile environment and sealed in a sterile container (e.g. a sealed plastic bag). The sampling filter unit may be removed from its sterile container whilst being held by its tab to avoid contamination. It may then be moved through an aqueous environment to capture sample material in the filter membrane or water can be pushed through the membrane by using pumping devices or it can be deployed in the environment for accumulating of eDNA material.

[0059] The entire sampling filter unit may then be placed into an environmentally sealed container to preserve it until further laboratory processing using a DNA-suitable preservation method. DNA-suitable preservation methods include freezing, preservation with a buffer or desiccation. The container may be a resealable bag or other suitable container. The container and sampling filter unit may then be transported to a laboratory for processing.

[0060] At a laboratory the sampling filter unit may be removed from the enclosure and the filter membrane may be removed from the sampling filter unit. The filter membrane may be removed in laboratory conditions without sample contamination. The filter membrane may then be processed in laboratory conditions for environmental DNA extraction and analysis.Figures 7 to 10 show an environmental DNA sampling apparatus according to an example embodiment. A body 9 defines a hollow internal region. The body may be of generally frusto-conical form with a port 10 connected to the narrow end. Port 10 provides a fluid flow path from the internal region. Other shapes could be used where the body is of a shape that converges towards the port.

[0061] An opening 11 is provided at the wide end of body 9. A filter receiver 12 is provided to receive a filter unit 14 of the type described above. The filter receiver may include a guide in the form of annular recess 13 configured to allow a filter unit 14 to be slidably inserted or removed. When a filter unit is inserted in guide 13 it covers the opening 11 such that flow into the internal region must be through the filter unit. In this way the filter receiver is positioned to receive fluid entering the internal region before it engages with any other surface of the apparatus, avoiding potential contamination from the apparatus.

[0062] The filter unit 14 could also be magnetically secured to body 9. One or more magnetic attachment elements for securing a filter unit may be secured to body 9 at opening 11 with complementary magnetic attachment elements provided on the filter unit 14. The one or more magnetic attachment elements may be one or more magnets. One or more magnetic attachment elements of the apparatus may also be one or more ferromagnetic elements, with a complementary magnet for the other part.

[0063] The port 10 may have ribs 15 to assist attachment to a tube 16 of a water pumping device 17 as shown in Figure 15B.

[0064] An environmental DNA sample can be obtained from an aqueous environment using a sampling filter unit 14 in the form of the device described above having a removable filter membrane. The sampling filter unit 14 may be preassembled in a sterile environment and sealed in a sterile container (e.g. a sealed plastic bag). The sampling filter unit may be removed from its sterile container being held byits tab to avoid contamination. It may then be held by its tab and inserted into the filter receiver.

[0065] The body 1 may then be inserted into an aqueous environment to be sampled and the water pumping device 17 driven for a required period to draw fluid from the environment through the filter unit 14 to obtain a desired amount of sample material on the filter membrane. The entire sampling filter unit 14 may then be removed by holding the tab and sliding it out of filter receiver 12 and it may then be placed into an environmentally sealed container to preserve it until further laboratory processing using a DNA-suitable preservation method. DNA-suitable preservation methods include freezing, preservation with a buffer or desiccation. The container may be a resealable bag or other suitable container. The container and sampling filter unit may then be transported to a laboratory for processing.

[0066] Figures 11 to 14 show a variant to the design of Figures 7 to 10 in which instead of having a ribbed port at the narrow end of the body an aperture 19 is provided in body 18 for receiving a tube and a slot 20 allows opposing sides to be drawn together when a fastener is secured through apertures 21 (provided on both sides). Otherwise the design is as per the design of Figures 7 to 10.

[0067] Figure 15A shows another variant in which the sampling apparatus 46 has a plurality of openings 47. Each opening 47 may have an associated filter receiver 48 (only two indicated) of any of the types described above. The apparatus 46 can have a closed base with an outlet (not shown) attached to rim 49 converging to connect to a pipe 16 of the system shown in Figure 15B.

[0068] Figures 16 to 19 show an underwater environmental DNA sampling apparatus which can employ the filter unit of Figures 1 to 6. Body 22 has a shape that is hydrodynamically optimised to maintain a desired depth and orientation. A central cavity 23 has an inlet 24 at the front and an outlet 25 at the rear with a constricted region 26 in the middle. One or more openings 27 may be providedfrom the interior through the body from the constricted region 26 utilising the Venturi effect to induce fluid flow from the exterior through each opening 27 into the central cavity 23. In this example 3 openings are provided with equal radial separation.

[0069] A removable filter unit 28 of the type shown in Figures 1 to 6 may be provided over each opening 27. Each filter unit may slide into and out of a filter receiver 29 as in the previous examples. The filter receiver may be in the form of a guide.

[0070] Alternatively, each removable filter can include one or more magnetic attachment elements for securing each removable filter to complementary magnetic attachment elements about a respective opening. The one or more magnetic attachment elements of the removable filter can be one or more magnets. The one or more magnetic attachment elements about each opening can be one or more magnets. Alternatively a magnetic attachment element on one part can be used with a ferromagnetic element on the other part.

[0071] Each filter 28 is positioned to receive fluid entering the body before it engages with any other surface of the apparatus. Due to the Venturi effect more fluid flows through the filter unit 28 than if it were placed over the inlet 24 or outlet 25.

[0072] Body 22 can be provided with stabilisation surfaces. In this example lateral stabilisers 30 and 31 are provided for roll control, tail stabilisers 34 (opposite one not visible) are provided for pitch control and vertical rudders 32 and 33 are provided for yaw control. These stabilising surfaces may be of fixed form set to achieve a desired hydrodynamic performance. For example they may be set to prevent roll and maintain a straight course but with a slightly negative pitch of tail stabilisers 34 to ensure that the device descends to a desired depth when towed by a line 35. By setting the length of the towing line and the speed of towing the device will maintain a desired depth by appropriate pitch setting. Typically, theapparatus may be towed at a speed of between 5 to 10 knots and remain stable to minimise drag during use.

[0073] In an alternative embodiment shown in Figure 20 adjustable control surfaces are employed. Body 36 is provided with lateral stabilisers 37 and 38 having control surfaces 39 (opposite side not visible) for roll control, tail stabilisers 40 (opposite one not visible) with control surfaces 41 (opposite one not visible) for pitch control and vertical rudders 43 and 44 with control surfaces 44 and 45 for yaw control.

[0074] It will be appreciated that only some stabilisers may be provided with control surfaces or that different configurations may be employed. For example the tail stabilisers and vertical rudders may be replaced with a V tail to perform the functions of both.

[0075] In the example of figure 20 the device could be towed with its operation controlled using the control surfaces. Control could be via telemetry from the surface communicated by wire or using wireless communication. Alternatively the apparatus may be provided with a controller for autonomous control.

[0076] The underwater environmental DNA sampling apparatus may operate as an ROV remotely operated vehicle or fully autonomous vehicle (with a propulsion unit added). A controller can control each control surface via suitable actuators to achieve a desired position and / or orientation and / or attitude of the apparatus. One or more sensors can supply information to the controller to facilitate control. The sensors can include one or more of a pressure sensor, a temperature sensor, an accelerometer, a magnetometer, a gyroscope, an IMU, GPS, a light sensor, a sound sensor, a depth sensor, and a flow meter to monitor the amount of water passing through filter units. The controller can include memory to store details of a desired collection path (position, depth, speed etc.) and control operation autonomously based on sensor information. GPS may be used on the surface to navigate to a desired collection point.The apparatus may alternatively be provided with no stabilisers or control surfaces and be attached to a stationary object to allow passive collection in a water flow.

[0077] The apparatus may alternatively be attached to another vehicle, such as an ROV, to allow collection of eDNA as an ancillary function.

[0078] An environmental DNA sample can be obtained from an aqueous environment using the underwater environmental DNA sampling apparatus of Figures 16 to 19 using a sampling filter unit 28 in the form of the device described in Figures 1 to 6 having a removable filter membrane. The sampling filter unit 28 may be preassembled in a sterile environment and sealed in a sterile environment (e.g. a sealed plastic bag). The sampling filter unit may be removed from its sterile environment being held by its tab to avoid contamination. It may then be held by its tab and inserted into the filter receiver 29.

[0079] The underwater environmental DNA sampling apparatus may then be towed or otherwise deployed in an aqueous environment to be sampled for a required period to draw fluid from the environment through each filter unit 28 to obtain a desired amount of sample material on the filter membrane. Alternatively, water could be driven through the central cavity 23 whilst the apparatus is deployed in an aqueous environment. Each entire sampling filter unit 28 may then be removed by holding the tab and sliding it out of filter receiver 29 and it may then be placed into an environmentally sealed container to preserve it until further laboratory processing using a DNA-suitable preservation method. DNA-suitable preservation methods include freezing, preservation with a buffer or desiccation. The container may be a resealable bag or other suitable container. The container and sampling filter unit may then be transported to a laboratory for processing.

[0080] It will be appreciated that the devices and methods described above avoid sample contamination. During collection the filter is the first thing to interact with the flow, avoiding contamination from the sampling apparatus. The filter unit can beeasily inserted and retrieved from the device using the handling tab, again avoiding contamination. During transport the filter unit is stored using a DNA-suitable preservation method. The transported filter unit is compact and easy to transport, whilst still avoiding sample contamination. The devices and systems are easy to use with filter units easily inserted and removed.

[0081] These devices and methods provide an effective way to concentrate eDNA to ensure sufficient quantities for analysis and to increase detectability of rare taxa. Cross-contamination is reduced by minimised in-field handling interference with the sampling material. eDNA is protected throughout the process to maintain the integrity of sampled molecules.

[0082] While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the Applicant's general inventive concept.

Claims

CLAIMS:

1. An environmental DNA sampling device comprising:a. a body having a tab extending therefrom and a flow path therethrough; andb. a retaining element configured to engage with the body so as to retain a filter membrane in the flow path,wherein flexing of the tab causes the retaining element to be released from the body.

2. A device as claimed in claim 1 wherein the body has a recess dimensioned to seat and accommodate the retaining element.

3. A device as claimed in claim 2 wherein the retaining element has a circular outer periphery.

4. A device as claimed in any one of claims 1 to 3 wherein the retaining element and body have inter-engaging features which retain the retaining element and body together until flexing the tab causes release.

5. A device as claimed in claim 4 wherein the inter-engaging features are in the form of a projection and a recess.

6. A device as claimed in claim 5 wherein the projection includes a ramp.

7. A device as claimed in any one of claims 4 to 6 wherein a plurality of inter-engaging features are provided.

8. A device as claimed in any one of claims 1 to 7 wherein the body includes a grill across the flow path.

9. A device as claimed in any one of the preceding claims wherein the body is formed of a compostable plastic.

10. A device as claimed in any one of the preceding claims wherein the retaining element is formed of a compostable plastic.

11. A device as claimed in any one of the preceding claims wherein the body is formed of a compostable plastic.

12. A device as claimed in any one of the preceding claims including a filter membrane secured between the body and the retaining element.

13. A device as claimed in claim 12 wherein the filter membrane has a pore size of between 5 -50 urn.

14. A device as claimed in claim 12 wherein the filter membrane is formed of nylon, glass fiber or polyethersulfone (PES) or other hydrophilic porous material.

15. A method of processing an environmental DNA sample comprising: a. obtaining an environmental DNA sample from an aqueous environment using a sampling filter unit having a removable filter membrane;b. placing the sampling filter unit into an environmentally sealed container and preserving it until further laboratory processing using a DNA-suitable preservation method; andc. removing the filter membrane from the sampling filter unit and processing it in laboratory conditions for environmental DNA extraction and analysis.

16. A method as claimed in claim 15 wherein the DNA-suitable preservation method is freezing, preservation with a buffer or desiccation.

17. A method as claimed in claim 15 or claim 16 wherein the sampling filter unit is a device as claimed in any one of claims 1 to 14.

18. An environmental DNA sampling apparatus comprising:a. a body defining a hollow internal region;b. a port providing a flow path from the internal region; and c. an opening into the internal region having a filter receiver adapted to removably receive a filter unit so that when the filter unit is received it covers the opening such that flow into the internal region must be through the filter unit.

19. An apparatus as claimed in claim 18 wherein the filter receiver is positioned to receive fluid entering the internal region before it engages with any other surface of the apparatus.

20. An apparatus as claimed in claim 18 or claim 19 wherein the filter receiver is a guide configured to receive the filter unit by sliding in and out of the guide.

21. An apparatus as claimed in claim 18 or claim 19 wherein the filter receiver includes one or more magnetic attachment elements for securing a filter unit with complementary magnetic attachment elements.

22. An apparatus as claimed in claim 21 wherein the one or more magnetic attachment elements of the apparatus are one or more magnets.

23. An apparatus as claimed in claim 21 wherein the one or more magnetic attachment elements of the apparatus are one or more ferromagnetic elements.

24. An apparatus as claimed in any one of claims 18 to 23 wherein the body converges towards the port.

25. An apparatus as claimed in claim 24 wherein the body is of generally frustoconical form.

26. An apparatus as claimed in any one of claims 18 to 23 wherein the port includes a coupling configured to attach to a tube of a water pumping device.

27. An apparatus as claimed in any one of claims 18 to 26 including an environmental DNA sampling device of any one of claims 1 to 14.

28. An apparatus as claimed in claim 27 including a water pumping device connected to the port.

29. A method of environmental DNA sampling comprising:a. inserting a filter unit into an environmental DNA sampling apparatus as claimed in any one of claims 18 to 28;b. drawing fluid out of the internal region through the port using a water pumping device so as to draw fluid into the internal region through the filter unit; andc. removing the filter unit for storage and processing.

30. An underwater environmental DNA sampling apparatus comprising: a. a body having an inlet and an outlet defining a fluid flow path through the device and a constricted region between the inlet and outlet;b. one or more opening through the body from the constricted region utilising the Venturi effect to induce fluid flow through each opening; andc. a removable filter provided over each opening.

31. An apparatus as claimed in claim 30 wherein each removable filter is held within a filter receiver.

32. An apparatus as claimed in claim 31 wherein each filter receiver is a guide configured to receive a filter unit by sliding in and out of the guide.

33. An apparatus as claimed in 30 wherein each removable filter includes one or more magnetic attachment elements for securing each removable filter to complementary magnetic attachment elements about a respective opening.

34. An apparatus as claimed in claim 33 wherein the one or more magnetic attachment elements of the removable filter are one or more magnets.

35. An apparatus as claimed in claim 33 wherein the one or more magnetic attachment elements of the removable filter are one or more ferromagnetic elements.

36. An apparatus as claimed in any one of claims 30 to 35 wherein each filter is positioned to receive fluid entering the body before it engages with any other surface of the apparatus.

37. An apparatus as claimed in any one of claims 30 to 36 wherein the body includes stabilisation surfaces.

38. An apparatus as claimed in claim 37 wherein one or more stabilisers includes a control surface.

39. An apparatus as claimed in claim 38 including a controller which controls each control surface to achieve a desired position and / or attitude of the apparatus.

40. An apparatus as claimed in claim 39 including one or more sensors supplying information to the controller.

41. An apparatus as claimed in claim 40 wherein the sensors include one or more of a pressure sensor, a temperature sensor, an accelerometer, a magnetometer, a gyroscope, an IMU, GPS, a light sensor, a sound sensor,a depth sensor, and a flow meter to monitor the amount of water passing through filter units.

42. An apparatus as claimed in any one of claims 30 to 41 having a hydrodynamically optimised body shape.

43. A method of environmental DNA sampling comprising:a. inserting a filter device into an environmental DNA sampling apparatus as claimed in any one of claims 30 to 42;b. placing the apparatus into an aqueous medium and causing fluid to pass through the apparatus from the inlet to the outlet so as to draw fluid from the aqueous medium through the filter device; andc. retrieving the apparatus and removing the filter device for processing.

44. A method as claimed in claim 43 wherein the filter device is a device of any one of claims 1 to 14.

45. A method as claimed in claim 43 or claim 44 wherein the apparatus is towed by a vessel.

46. A method as claimed in claim 45 wherein the vessel is a ROV.

47. A method as claimed in claim 45 or claim 46 wherein the apparatus is towed at a speed of between 5 to 10 knots.

48. A method as claimed in claim 43 or claim 44 wherein the apparatus is attached to a stationary object.

49. A method as claimed in claim 43 or claim 44 wherein the apparatus has control surfaces which are controlled to maintain a desired course.

50. A method as claimed in claim 49 wherein the control surfaces are controlled from the surface via telemetry.

51. A method as claimed in claim 49 wherein the control surfaces are controlled autonomously by a control system of the apparatus.

52. A method as claimed in claim 43 wherein fluid is pumped through the apparatus.

53. An environmental DNA sampling apparatus as claimed in any one of claims 18 to 23 having a plurality openings into the internal region, each having a filter receiver adapted to removably receive a filter unit.

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