Abstract:
The DNA Sampling Hook is a significant improvement on a method of obtaining a tissue sample from a live fish in situ from an aquatic environment. A tissue sample taken from a live fish can be used for DNA analyses, which can identify the species of fish, as well as the unique individual fish. Taking a small tissue sample without bringing the fish to the surface is important as it allows for observing the fish community without harming the individual fish by inducing barotrauma or other stresses associated with bringing a fish up from depth, which can be lethal to the animal. These tissue samples are obtained by hook and line methods and do not capture or traumatize the fish resulting in a non-lethal and non-destructive method of observing fish individuals and species. The DNA Sampling Hook is specifically designed to virtually eliminate a condition called double bites, in which more than one individual fish gives up tissue to the same hook. It is also designed to protect the tissue sample in an enclosed manner and the device can be reused repeatedly for a total overall reduction in cost for programs requiring extensive numbers of tissue samples for DNA analysis.

Description:
STATEMENT OF GOVERNMENT INTEREST 
       [0001]    The research that led to the development of the present invention was sponsored by the National Oceanic and Atmospheric Administration&#39;s (NOAA&#39;s) National Marine Fisheries Service (NMFS). NOAA is a part of the U.S. Department of Commerce, a component of the U.S. Federal government. The United States Government has certain rights in this invention. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to an improved DNA sampling hook for obtaining tissue samples from fish underwater, without bringing the fish to the surface. 
       BACKGROUND OF THE INVENTION 
       [0003]    Sampling of fish DNA is useful to marine biologists for a number of reasons. Such samples may be used to determine the types of fish within a fishery, the genetic diversity and structure of fish populations, the historical and present size of fish populations, assess fish population growth, determine migration patterns and barriers to fish and larval dispersal, detect the presence of genetic defects, and also determine the health of the fish population. Prior Art techniques of catching fish to obtain DNA samples are expensive and time consuming, as they require that the fish be caught, brought to the surface, a DNA sample taken, and then the fish released. In many instances the fish is severely injured or dies as a result. Thus a technique for obtaining a DNA sample from a fish without having to catch and release the fish is desirable. 
         [0004]    Fish biopsy devices are known in the art. One such device presently on the market is known as the Fish Biopsy Device. The Northwest Fisheries Science Center (NWFSC) has used the Fish Biopsy Device in prior studies in the summers of 2004 and 2005. This device, as designed, was used 1331 times and yielded 54% tissue samples, which produced usable DNA for identification of fish individuals and species. During its use, the exposed tip of the Fish Biopsy Device allowed for double bites in up to 52% of these tissue samples. The double bites then reduced the overall effectiveness of the identification from 54% collected samples to 26% for individuals and species. It was determined that the 26% identification was too low and that this number had to be improved. Additionally, the tip of the Fish Biopsy Device is difficult to replace and subsequently is just cut off from the main body for tissue analysis rendering the device unusable thereafter. This results in an overall higher cost to the projects, which require hundreds of hooks to perform scientific studies. 
         [0005]    Published U.S. Patent Application No. 2006/0106324A1, (Buckworth), incorporated herein by reference, discloses a fish biopsy device for obtaining biopsy material in situ, which comprises a hook(s) having a tip with a tube of non-pliable material having a sharpened edge, a bend, and a shank. The device appears to suffer from the same problems as the Fish Biopsy Device mentioned above, namely the same problems (i.e., double bite, retention of samples). The reference has also been filed as PCT WO 2004/049953 based upon a 2002 Australian Patent Application. 
         [0006]    Fishhooks and fishing gear are well known in the art as well. The following references describe Prior Art fishing gear. U.S. Pat. No. 4,858,371, (Preiser), incorporated herein by reference, discloses a retractable barb-less fishhook for sport fishing, which has an end of a bend segment carrying sharpened point and other end linked slidably movable flexible shank. This reference is directed toward a fish catching device and is relevant as background only. Note, U.S. Pat. No. 4,768,304, also incorporated herein by reference, is a family member. 
         [0007]    U.S. Pat. No. 5,363,588, (Konow), incorporated herein by reference, discloses a hook for fishing line which has smooth hook portion with cavity adjacent point and shank with line coupling. This reference is directed toward a fish catching device and is relevant as background only. 
         [0008]    U.S. Pat. No. 6,840,002, (Dick), incorporated herein by reference, discloses a de-hooking device for removing hook from fish or turtle&#39;s mouth, which has slidable bite sleeve capable of abutting surface of handle when positioned at one end of rod and abutting hook removal end when positioned at opposite end of rod. This reference is directed toward a fish catching device and is relevant as background only. 
         [0009]    U.S. Pat. No. 4,987,695, (Preiser), incorporated herein by reference, discloses a retractable barb-less fishing lure, which comprises a body having front and rear end, and also having longitudinal channel through body between front and rear ends. This reference is directed toward a fish catching device and is relevant as background only. 
         [0010]    U.S. Pat. No. 3,624,690, (Ashley), incorporated herein by reference, discloses a fishhook with retractable barb. A sleeve member in the form of a fishhook is slotted adjacent each of its closed ends. A spring wire member is slidably received in the sleeve and has one end formed to provide a barb retractable into the sleeve through one slotted end. The other end of the wire is looped and extends through the other slotted end of the sleeve. This reference is directed toward a fish catching device and is relevant as background only. 
         [0011]    U.S. Pat. No. 2,217,928, (Ward), incorporated herein by reference, discloses a fishhook with retractable barb. U.S. Pat. No. 5,884,428, (Shelton), incorporated herein by reference, discloses a self-releasing fishing hook apparatus. U.S. Pat. No. 5,946,846, (Cotton), incorporated herein by reference, discloses a spring loaded fishing lure with easily removed fishhook especially for use in catch and release sport fishing. U.S. Pat. No. 3,827,174, (Banker), incorporated herein by reference, discloses a fishing hook openable to release fish, which has pivoted hook releasably held by movable sleeve. U.S. Pat. No. 5,388,367, (Rydell), incorporated herein by reference, discloses a fishing lure having hook(s) with sheath-guard, which comprises a coil spring, fixed at one end to lure, and acting as deflective guard during fishing. 
         [0012]    U.S. Pat. No. 5,685,108, (Lepage), incorporated herein by reference, discloses a fishhook with catch-and-release characteristics—has two depressions with sharp leading edges in the wire of the hook. U.S. Pat. No. 5,491,925, (Carpenter, R. Carter), incorporated herein by reference, discloses a device for catching fish, which has a housing formed from first and second halves, with halves including port and longitudinally extending trough for receipt of leader. U.S. Pat. No. 3,397,477, (Hand), incorporated herein by reference, discloses a fishhook with a spring and pivoting mechanism. U.S. Pat. No. 3,497,985, (Margulies), incorporated herein by reference, discloses a fishing lure with retractable hook. 
         [0013]    U.S. Pat. No. 3,983,655, (Kolesar), incorporated herein by reference, discloses a weed resistant spinning fishing lure, which has a hook spun by a spring covered by sleeve part of rubber body resisting weeds. U.S. Pat. No. 5,6111,66, (Day), incorporated herein by reference, discloses a fishing lure apparatus which has a hook assembly and trigger assembly which includes fish-strike receiving portion and an unlocking portion which releases shaft assembly from locked position. U.S. Pat. No. 6,574,908, (Sanner), incorporated herein by reference, discloses a fishing lure for catching fish, which has fishing hooks each having one end secured to a spring-loaded plunger held in hook retracted position by trigger which is activated when fish bites on lure. U.S. Pat. No. 4,543,742, (Rand, Jr.), incorporated herein by reference, discloses an anesthetic or antiseptic injecting fishhook which has a U-shaped body with tubular well and sealable chamber for holding charge of liquid. 
         [0014]    Published PCT Application No. WO06069053, (Skiffington), incorporated herein by reference, discloses a test device and method for detection of sample analytes in which after sampling has occurred a closure is provided. Such a test device and method can be usefully employed to detect a variety of analytes including microorganisms. This reference appears to be relevant as background only as a sample-collecting device. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention comprises an improved DNA Sampling Hook for obtaining a tissue sample from a live fish in situ from an aquatic environment. A tissue sample taken from a live fish can be used for DNA analyses, which can identify the species of fish, as well as the unique individual fish. Taking a small tissue sample without bringing the fish to the surface is important as it allows for observing the fish community without destroying the individual fish by inducing trauma or barotrauma as the fish brought up from depth, which is a very destructive method. These tissue samples are obtained by hook and line methods and do not capture or traumatize the fish resulting in a non-lethal and non-destructive method of observing fish individuals and species. The DNA Sampling Hook is specifically designed to virtually eliminate a condition called double bites, in which more than one individual fish gives up tissue to the same hook. It is also designed to protect the tissue sample in an enclosed manner and the device can be reused repeatedly for a total overall reduction in cost for programs requiring extensive numbers of tissue samples for DNA analyses. The DNA Sampling Hook offers many improvements over the Prior Art. 
         [0016]    DNA Sampling Hook described herein is a significant improvement on an existing technology currently on the market as the Fish Biopsy Device. Because an improved Fish Biopsy Device was not available, NWFSC embarked on a development effort to design a better device with the intent of increasing the amount of tissue for DNA analyses, better protect it, and eliminate the double bite problem associated with the current technology. In addition, a design goal was to produce a device, which was reusable, which could result in a net lower cost for these types of devices. Twenty nine prototype hooks were used in a captive test of 13 fish contained in a large tank on NWFSC property and the results were encouraging with ample amounts of tissue, no double bites detected, and greater than 90% DNA obtained. It was decided that the design was worthy of a field test. 
         [0017]    The new design was finalized and drawings were made and a small procurement was issued to a local small machine shop for fabrication of 50 reusable hook assemblies and 400 replaceable sampling tips. These parts were then used in a hook and line survey in California, the results of which are still under analysis. During this survey the older technology, the Prior Art Fish Biopsy Device, and the new design of the present invention, the DNA Sampling Hook, were used on two fishing boats during a hook and line survey in the waters off southern California. The results of this study are to be analyzed, and published in the scientific community. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a side view of the DNA sampling hook of the present invention in the cocked position. 
           [0019]      FIG. 2  is a side view of the DNA sampling hook of the present invention in the fired and covered position. 
           [0020]      FIG. 3  is a side view of the DNA sampling hook of the present invention illustrating the removable tip, allowing re-use of the device. 
           [0021]      FIG. 4  is a side view of the DNA sampling hook of the present invention in position ready to bait and deploy. 
           [0022]      FIG. 5  is a side view of the DNA sampling hook of the present invention with the hook beginning to rotate as the fish bites. 
           [0023]      FIG. 6  is a side view of the DNA sampling hook of the present invention illustrating the compression spring-loaded sleeve pushing up the tip holder. 
           [0024]      FIG. 7  is a side view of the DNA sampling hook of the present invention illustrating the sleeve continuing to push the hook tip straight. 
           [0025]      FIG. 8  is a side view of the DNA sampling hook of the present invention illustrating the completely covered top at the end of the compression spring extension. 
           [0026]      FIG. 9  is a side view of the DNA sampling hook of the present invention illustrating details of the sampling hook components. 
           [0027]      FIG. 10  is an enlarged perspective view of the DNA sampling hook of the present invention illustrating how the tip holder holds the sleeve in position prior to activation. 
           [0028]      FIG. 11  is an enlarged perspective view of the DNA sampling hook of the present invention illustrating how the tip holder triggers the extension of the sleeve when a fish bites on the hook. 
           [0029]      FIG. 12  is a side view of an alternative embodiment of a flat one-piece sampling hook portion with a slot attachment. 
           [0030]      FIG. 13  is a side view of an another alternative embodiment of a sampling hook holder with a slot attachment and removable sampling hook. 
           [0031]      FIG. 14  is a perspective view of the flat one-piece sampling hook portion with a slot attachment of  FIG. 12 . 
           [0032]      FIG. 15  is a perspective view of the sampling hook holder of  FIG. 13  with a slot attachment and removable sampling hook. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]      FIGS. 1-11  depict the DNA Sampling Hook of the present invention.  FIG. 1  is a side view of the DNA sampling hook of the present invention in the cocked position. Referring to  FIG. 1 , the DNA sampling hook comprises a main shaft  140  provided with an eye  145  for attaching fishing line or fishing gear tackle. Attached or sliding on main shaft  140  is compression spring  130 , which may be provided with a stop (not shown) to prevent it from sliding off main shaft  140 , or may be held in place with a ring, clip, or the like through eye  145 . 
         [0034]    Main shaft  140  includes an attach point  145  for the line or fishing tackle, and also acts as the carrier of compression spring  130 , the body on which sliding sleeve  120  may move. Main shaft  140  also includes a hinged attached point  155  for the tip holder  150 . Main shaft  140  and tip holder  150  are of substantially the same diameter ensuring an easy transition route for sliding sleeve  120 . Main shaft  140  may include a flat side, which the rear portion of sliding sleeve  120  is keyed (not shown) to in order to stop its forward movement at full extension of compression spring  130 . 
         [0035]    Sliding sleeve  120  slides along main shaft  140 , and has a diameter slightly larger than main shaft  140  so that it may slide freely. Sliding sleeve  120  is substantially the same diameter as compression spring  130  so that one end of compression spring acts against one end of sliding sleeve  120 . Hinge pin  155  allows tip holder  150  to hinge freely with main shaft  140 . Replaceable tip  110  may be removably attached to tip holder  150 . All of the components used may be made from Stainless Steel and adequate precision used to make the parts uniform and interchangeable. Other materials may be used, e.g., for freshwater applications, such as anodized aluminum, carbon steel, and the like. Alternately the assembly in whole or part may be made from plastic or other composite materials or the like. 
         [0036]    Sliding sleeve  120  holds tip holder  150  to keep it at the fully cocked position and proper angle for initially hooking a fish. Sliding sleeve  120  also acts as a tissue protection sleeve, which covers replaceable tip  110 , which has the fish tissue sample when the device is triggered. Compression spring  130  functions as a forcing mechanism, which holds tip holder  150  in a cocked position without the aid of a secondary device. It also is the closing mechanism to encase the tissue sample on the replaceable tip  110  with sliding sleeve  120  as tip holder  110  is rotated on hinge pin  155 , allowing it to enter sliding sleeve  120  as compression spring  130  fully expands to length. 
         [0037]    Replaceable tip  110  may comprise a hollow tube or the like, having a series of serrations to scrape tissue as shown. One end of replaceable tip  110  may be sharpened or thinned, so that when a fish bites onto the DNA sampling hook, replaceable tip  110  pierces through the fish&#39;s flesh, and a sample of flesh is retained within the tubular portion of replaceable tip  110  along with flesh caught in the serrations. 
         [0038]    Hinge pin  155  serves as the connecting device to hold main shaft  120  and tip holder  150  together allowing tip holder  150  to rotate freely and keeping the two aligned when compression spring  130  forces sliding sleeve  120  over replaceable tip  110 . Tip holder  150  serves as a mounting point and holder for replaceable tip  110  as well as the triggering point for releasing sliding sleeve  120  when it is moved sufficiently to allow it to enter sliding sleeve  120  for encasing the tissue sample. 
         [0039]      FIG. 2  is a side view of the DNA sampling hook of the present invention in the fired and covered position. As illustrated in  FIG. 2 , when replaceable tip  110  and tip holder  150  are rotated counter-clockwise in the picture, sleeve  120  may be driven over tip holder  150  and replaceable tip  110  by compression spring  130  so as to cover all of tip holder  150  and replaceable tip  110 . 
         [0040]      FIG. 3  is a side view of the DNA sampling hook of the present invention illustrating the removable tip, allowing re-use of the device. In this Figure, replaceable tip  110  is shown removed from tip holder  150 . Replaceable tip  110  may be held in place with a tab  160  which may engage a slot or groove  111  in tip  110 . To remove replaceable tip  110  from tip holder  150 , tab  160  may be pressed through slot  111  in removable tip  110  to allow removable tip  110  to slide off tab  160 . In this preferred embodiment, a tab  160  is used, as it maintains the proper orientation of removable tip  110  to tip holder  150 . However, other types of attachment mechanisms may be used, including but not limited to threaded connections, bayonet joints, adhesives, snaps, and the like. 
         [0041]      FIGS. 4-8  illustrate the sequence of steps in the deployment of the DNA sampling hook of the present invention.  FIG. 4  is a side view of the DNA sampling hook of the present invention in position ready to bait and deploy. In this position, the entire hook may be baited with typical fish baits. Alternately the entire assembly may be attached to an artificial lure, fly or the like. If bait is to be used, care should be taken to insure that portions of the bait are not forced into the tubular portion of replaceable tip  110 . A cap or other device (not shown) may be placed over replaceable top  110  during baiting to prevent such ingress of bait flesh. Bait DNA is different and may not be a factor in locating the target fish DNA. However it is preferable to minimize the inclusion of bait flesh in the sample. 
         [0042]      FIG. 5  is a side view of the DNA sampling hook of the present invention with the hook beginning to rotate as the fish bites. Once baited, the DNA sampling hook of the present invention may be attached to traditional fishing gear (not shown) and lowered into the water. As with traditional fishing, fish are attracted to the bait or lure and bite down on the hook. When replaceable tip  110  pierces the flesh of the fish (e.g., jaw or the like), a portion of the fish flesh is retained within the interior of replaceable tip  110 , which is tubular and hollow in construction, as well as in the serrations. The serrations may produce more tissue than the hollow area. 
         [0043]    Once the fish bites on the hook, the user then reels in the line, or the fish will pull back from the hooked bait. In either event, as the fish pulls back from the hook, the replaceable tip  110  and tip holder  150  will rotate counterclockwise in the direction of arrow  115 , as illustrated in  FIG. 5 .  FIG. 6  is a side view of the DNA sampling hook of the present invention illustrating the compression spring-loaded sleeve pushing up the tip holder. Once replaceable tip  110  and tip holder  150  start to rotate in direction  115 , sleeve  130  is no longer restrained and compression spring  130  starts to push sleeve  120  in direction  125 . 
         [0044]    Replaceable tip  110  acquires the tissue sample from the fish using built-in slots and barbs, which effectively scrape or tear tissue when encountered by the fish. Replaceable tip  110  may be preserved in the field and returned to the laboratory for tissue removal and analysis. Replaceable tip  110  may be reused if cleaned of all tissue and DNA material. 
         [0045]      FIG. 7  is a side view of the DNA sampling hook of the present invention illustrating the sleeve continuing to push the hoot tip straight. In  FIG. 7 , replaceable tip  110  and tip holder  150  are now substantially axial with main shaft  140  and sliding sleeve  120 . Compression spring  130  can now push sliding sleeve  120  in direction  125  freely.  FIG. 8  is a side view of the DNA sampling hook of the present invention illustrating the completely covered top at the end of the compression spring extension. Sliding sleeve  120  now completely covers replaceable tip  110  and tip holder  150  by moving in direction  125 , thus protecting the fish tissue on tip  110 . 
         [0046]    This spring action acts to automatically eject the DNA sampling hook from the fish, while creating a minimum of injury to the fish, and also protecting the sample within the replaceable tip from loss or damage. In addition, since replaceable tip  110  is now protected by sliding sleeve  120 , a fish cannot bite on the device again, and in addition, sliding sleeve  120  prevents other fish from biting on the device. Thus, a DNA sample is received only from the first fish to bite, and not from a plurality of fish. As the DNA sampling hook is now released from the fish, it may be reeled in to retrieve the sample. 
         [0047]      FIG. 9  is a side view of the DNA sampling hook of the present invention illustrating details of the sampling hook components. Once retrieved (onto a boat, dock, or the like), sliding sleeve  120  may be pushed back to the position shown in  FIG. 9  and replaceable tip  110  and tip holder  150  cocked back into the original position to hold sliding sleeve  120  in place. Replacable tip  110  may then be removed as illustrated in  FIG. 3 , and the entire tip, including sample may be tagged and stored for later analysis. A new replacement replaceable tip  110  may then be quickly attached to tip holder  150  and the process quickly repeated. Since there is no need to remove the sample from the DNA sampling hook, more sampling can occur in a given time. In addition, in a rocking boat or on a dock, it may be difficult and unsanitary to try to remove flesh samples from a Prior Art hook, catalog and store such samples. The replaceable tip of the present invention solves this problem, and also allows unskilled persons to collect such samples with less risk of contamination or the like. 
         [0048]      FIG. 10  is an enlarged perspective view of the DNA sampling hook of the present invention illustrating how the tip holder holds the sleeve in position prior to activation.  FIG. 11  is an enlarged perspective view of the DNA sampling hook of the present invention illustrating how the tip holder triggers the extension of the sleeve when a fish bites on the hook. As illustrated in  FIG. 10 , tip holder  150  is provided with a hinge pin  155  which hinges tip holder  150  to main shaft  140 . A tab  156  is provided on tip holder  150  such that it extends through a portion of main shaft  140  and acts as a stop to hold sliding sleeve  120  in place. 
         [0049]    Once tip holder  150  rotates through a 40 degree range of motion  158 , tab  156  no longer locks sliding sleeve  120  in place, and sliding sleeve, pushed by compression spring  130  may then act upon tip holder  150  to move tip holder  150  as illustrated in  FIGS. 4-8 . Note in this example, a 40 degree range of motion  158  is illustrated in the preferred embodiment, however other suitable angles may be used within the spirit and scope of the present invention. 
         [0050]    The DNA Sampling Hook as some distinct and important differences from the Fish Biopsy Device. They are depicted in the following table: 
         [0000]    
       
         
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 DNA Sampling Hook 
                 Fish Biopsy Device 
               
               
                   
               
             
             
               
                 Reusable design of major components including 
                 Disposable device, the sampling tip is 
               
               
                 reuse of the sampling tip 
                 unscrewed or cut off rendering the device 
               
               
                   
                 unusable 
               
               
                 Eliminates or nearly eliminates double bites 
                 Cannot prevent double bites 
               
               
                 Encloses tissue sample to protect it from being 
                 Exposed tissue sample with no protection 
               
               
                 washed away or eaten by smaller animals 
                 from water column or small animals 
               
               
                 Mechanical action releases fish automatically 
                 Body must be bent to release fish, device 
               
               
                 after triggering 
                 has brought fish to the surface resulting in 
               
               
                   
                 fatalities 
               
               
                 Ample amounts of tissue collected for good 
                 Trace amounts of tissue collected for 
               
               
                 DNA analysis 
                 minimal DNA analysis 
               
               
                 Positive snap action preferred for one time 
                 No positive action, scientific sampling is 
               
               
                 scientific sampling 
                 not assured 
               
               
                   
               
             
          
         
       
     
         [0051]    Applications for the DNA Sampling Hook are widespread and because the design protects the tissue sample it can be used in more scientific studies than prior art. The Fish Biopsy Device for example is used typically on hook-and-line research where the principal investigator or fisherman is involved in actively setting the hook into the fish and then retrieving it immediately to retrieve the tip and tissue sample. 
         [0052]    The DNA Sampling Hook on the other hand, can be left in situ, because the sleeve protects the tissue sample. This tissue protection will allow the hook to be used in long line surveys where lines with hundreds of hooks are deployed and then later retrieved. Other applications include the deployment and retrieval of the DNA Sampling Hooks on robotic devices to various locations in aquatic environments not reachable by current hook and line methods. While disclosed for use with fish, the DNA sampling hook may be used also for other types of marine animals, amphibians, reptiles, land animals, mammals, and even plants. 
         [0053]      FIG. 12  is a side view of an alternative embodiment of a flat one-piece sampling hook portion with a slot attachment.  FIG. 14  is a perspective view of the flat one-piece sampling hook portion with a slot attachment of  FIG. 12 . In this embodiment, the tip holder and barbed top are combined into one single-piece tip  110 A. Single piece tip  110 A may be made from flat stock and may be solid, as opposed to hollow and cylindrical as in previous embodiments. Alternatively, single-piece tip  110 A may be made as a hollow rectangle or the like to capture tissue samples. In yet another alternative, single-piece tip  110 A may be made of round cross-section tubing as in prior embodiments, flattened at one end to form an attachment point. 
         [0054]    Single piece tip  110 A may have a flat portion at least one end with a slot  157  for attachment to the main shaft  120  as in Prior Figures. Slot  157  slides onto pivot  155  and allows the entire single piece tip  110 A to be removable by sliding off one-piece tip from main shaft  120  via slot  157 . Barbs  115  are provided at the other end of single piece tip  110 A to capture tissue samples between barbs  115 . In the preferred embodiment, single-piece tip  110 A is made of solid stock and barbs  115  are the sole sampling element for tissue. Alternately, single-piece tip  110 A may have a round or other open cross-section and may be hollow inside as in the other tips in order to capture tissue samples. The use of slot  157  allows for easy removal and replacement and is lower in cost that other designs, as the number of parts is reduced. 
         [0055]      FIG. 13  is a side view of an another alternative embodiment of a sampling hook holder with a slot attachment and removable sampling hook.  FIG. 15  is a perspective view of the sampling hook holder of  FIG. 13  with a slot attachment and removable sampling hook. In this embodiment, round tip  110  and holder  150 A are essentially the same as in prior embodiments, except that holder  150 A contains slot  157  for easy removal and replacement. 
         [0056]    The overall size of the invention may be altered depending upon which size fish (or animal or plant) is to be sampled. The overall hook size may be scaled up or down to match the size of the target fish or other sample target. As may be appreciated from the foregoing description, the sampling hook of the present invention better protects the sample during the handling on the boat, transfer to the lab, and handling in the lab. Prior art sampling devices were more subject to contamination or loss of tissue. 
         [0057]    While the preferred embodiment and various alternative embodiments of the invention have been disclosed and described in detail herein, it may be apparent to those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope thereof. 
         [0058]    For example, the sampling hook of the present invention may be used be used in Robotic applications such as manned and unmanned vehicles, ROVs, AUVs, tethered or free-floating Buoys, use by Scuba divers. While the present invention has been used in a saltwater environment, the sampling hook of the present invention may be applied to freshwater applications, such as estuaries, lakes, ponds, and the like. The sampling hook may also be used in tanks and closed environments. As previously noted, the sampling hook may be used for biting animals other than fish, such as amphibians or the like, or may even be used to snag samples from non-biting animals or even plants.