Transmitter Implantation Surgery on Striped Bass

Tim Arienti

11/15/04

Here I will explain to you how we surgically implant acoustic tags in Striped Bass.  The entire procedure takes less than 30 minutes from  time landed to time released.  The majority of fish that we tag are caught with hook and line and are tagged either in the boat or back in the lab at UNE.  This procedure is common with any fish tagging surgery and has a very high survival rate.  We havent had any mortalities from this procedure.  Generally 3 people are involved in this process, although it can be done by two.  Usually one person performs surgery, one holds the fish, and the other writes down data and assists with anything that doesnt involve getting wet.  Feel free to email me if you have any questions.

1). Once we actually catch a taggable fish we place it in a large igloo ice chest with 20 gallons of water and pre-measured anaesthetic.  Water is stirred to mix in anaesthetic.  An aerator is placed in cooler to mix in the anaesthetic and give the fish oxygen.  Cooler is covered until fish is partially under.  The fish will be much calmer and go under easier if the cooler is covered. 

2). We now wait for fish to loose equilibrium. (5-15 min) When fish starts to float belly up but is still breathing, we test for response from fish by pinching anal fin.  When there is no response, we know the fish is ready.  Someone will prepare and start to fill out data sheet while waiting for fish to loose equilibrium REMEMBERING to write down the LOTEK and floy tag code now! It is tough to read a tag number once it is inside the fish, we have learned that from experience.  Surgery gear is laid out with a new scalpel blade, and a new suture kit. Also readied is the scale sample envelope and fin clip vial.  Transmitter is sterilized by putting it in antiseptic bath (benz-all) with surgery tools. Anyone handling fish will now put on gloves. Just before proceeding, tag is removed from bath and placed on sterile gauze to dry.  

3).  Fish is measured  while waiting for it to go out.  It doesn’t need to be completely under to get a length measurement.  As fish goes out completely, now is time to start.  Scale sample is taken first.  Approximately half a dozen scales are taken from below lateral line, and below middle of first spiny dorsal fin.  Fin clip is taken next.  A pencil eraser size fin clip from point of second dorsal fin is taken for later DNA analyzation.  

4). The assistant cradles the fish so that the belly side is above water, but mouth and at least half of gills are under.  Two rows of scales are removed from incision site, to one side of ventral midline and forward of the vent. No major veins or arteries pass through the midline of the fish so this is a very safe area to make an incision.

5) A small incision is made in the scale free area with the blade. Once the peritoneum (stomach lining) is punctured, a blunt-nose scissor is used to open the cut about 2 cm.  Blunt-nosed scissors are blunt on only one shear nose. This end goes into the fish to prevent damaging internal organs. The scissor Snip upwards. 

6) The tag is lightly coated in Neosporin/Triple Antibiotic to lube it and coat the incision on insertion. Tag is gently pushed in and turned to insert it into the cavity. Sometimes, the assistant helps by using the spatula end of the scalpel handle like a retractor to “shoe-horn” the incision, which may want to close inward if small.

7) A No. 3/0 absorbable suture is clipped into hemostat.  We suture down into the flesh and up on the other side following the suture blade curve, making sure not to hit internal organs with needle.  The blade is then pulled almost all the way through to leave about 2 inches free. Suture blade is then released and two surgeons knots are tied and cinched tight. This is done two or three more to close incision. Before the last incision, we insert the external anchor tag (coated with Neosporin) snug against the ventral end of incision, then finish final suture. We can then check the suture by attempting to push the scalpel handle down into the cut.  These sutures will absorb as the fish heals, leaving the fish with only a small scar from the incision. 

8).  The fish is now put into a bucket or net to be weighed.

9).  An assistant now takes a post-surgery picture of the fish before fish is moved into recovery tank (or cradled overboard). The fish is held upright and moved back and forth to move fresh water over its gills.  Within a few minutes we will notice that the fish will start to respond and when it has enough strength, we let it swim away under its own power.  As we wait for it to wake, we give it an injection of antibiotic (liquimyacin) into the dorsal sinus to help protect against infection.