Thursday, September 5, 2013

The Rant Chapter 3

The Rant Chapter 3
Tagging big drum with transmitters, then using a grid system to relocate them was proving to be much more difficult than we suspected.   If we were going to learn anything about these fish, we needed to concentrate our effort into following individuals and monitoring their behavior.   Hopefully we would run into some of the other several dozen fish that we had tagged with transmitters, learning where they were congregating and hopefully where they were spawning.   In 1999 very little was known about big red drum, including where they were spawning and if that was even occurring in the Neuse River.  If so, this would be one of the few red drum populations that was documented as spawning somewhere other than the open ocean. 

To better track individuals, we recruited another boat.  The plan now was to tag a fish and follow  that fish for 24 hours/day for 3 days.  We would use two boats with 12 hour shifts on each boat.  We would start that afternoon, this time fishing in the center of our grid, off Turnigan Bay, hopefully tagging a fish, following it through the night and having our relief boat pick up the trail the next morning.  

This fish that we tagged off Turnigan Bay that night was a special fish.   We got it in the boat, measured it’s girth, standard, fork and total lengths and we tagged the fish, but the transmitter wasn’t working.   It took a few minutes to get another tag prepared and I was dumping buckets of water on the fish to keep it from drying out.    With the fish now ready to go, bleeding from 3 tags, the tag from the failed transmitter which was now removed,  a regular NCDMF  tag and the tag with the new transmitter.   This big drum was very weak when we released it after being in the boat for many, many long minutes.  I spent some time reviving it and he slowly swam off.   We slowly followed the fish into the night, the fish traveled a couple of miles then stopped.    Was it dead?

We got close to the fish and quietly anchored the boat.  Every few minutes we would put the hydrophone in the water and listen to the strong signal of the “beep”.   It wasn’t moving.  Several hours later, just as the sky was lightening to the eastward, we put the hydrophone in the water and the “beep” was much fainter, this fish was not dead, but on the move and so were we if we were going to keep up with it.

This fish was not only moving, but also moving really, really fast along the deep edge of the shoal.  As the sky was lightened, birds started to pick, slicks started to pop up and we would actually see a drum occasionally bust the surface.   Our tagged fish appeared to be in a school.   The biologist using the hydrophone pointed in the direction that the beep was coming from and a couple hundred yards away, exactly where he was pointing, a big drum came to the surface and crashed a crab.   The drum that we were worried about surviving 10 hours earlier was now actively feeding and apparently rejoined a school.   This was fantastic news.

Over two years, we tagged several dozen drum with transmitters and followed them for countless hours, dodging daily thunderstorms and weathering nor’easters on the water, through scorching days and dark, rough nights.  This is some of what we learned.  

We NEVER found the same fish in the same place on two days in a row!  Don’t worry about it if someone is “in your spot”, just get in the similar depth of water and keep your distance, you’ll get ‘em. 
It may be a good spot and drum may pass through there every day, but it may not be the same drum.

 Most of the drum that we tagged traveled the 8-14 foot drop off, that’s always a good bet, but if they weren’t there, they would often be running the shoreline.

We repeatedly observed schools and individuals of red drum, just “laying up” in an area for hours.   Perhaps they were sleeping, perhaps they were slowly following schools of menhaden, eating the scraps from feeding bluefish, but these fish were not working hard and not moving much at all.   This behavior was seen most often in the middle of the day and late at night/early in the morning.    

The secrets of catching drum exhibiting this behavior have recently been unlocked.   Although Capt. Gary Dubiel and I are often like oil and water, I have to give him the credit he is due for pioneering the popping cork craze.  

Drum caught and tagged together would later be found apart, perhaps with other drum that we had tagged.  Days later the two fish would be back together in the same school again.  There seemed to be a lot of mixing of schools and these schools were covering a large area, alleviating worries that drum fishermen were concentrating their effort on one small spawning population. 

But there were concerns about these recreational fishermen, most of them fishing at night and most of them using j-hooks and deep-hooking huge numbers of big drum.   What was the mortality rate of these deep hooked fish?   Some suspected that mortality of deep hooked drum  would be near 100%.   If this were true, then recreational fishermen could due irreparable damage on the spawning population.  

Regardless of the actual mortality rate, there has to be a way of reducing deep hooking which cannot be good for those fish.   The focus of our study changed from identifying drum movement and preferred habitat to documenting mortality rates of deep hooked fish and how to reduce deep hooking.    

We began to explore with circle hooks and tag some deep-hooked fish with our transmitters.   Instead of retrieving our transmitters off of bloated, floating dead drum, the deep-hooked fish that we tagged seemed to have done reasonably well, surviving the deep hooking experience.   With only a few deep hooked fish with transmitters and our season coming to an end, plans were already in the works to focus on the impacts of hook and line fishing.   I’ll sum up our findings of the next three years of research in the next rant.