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Topic Review (Newest First)
03-15-2000 09:22 PM
ssully
RE:Catch & Release Mortality

Thanks Pete.
03-13-2000 08:07 AM
Pete
RE:Catch & Release Mortality

Sully & other Board members,

Well been away for a while. Trying to get the thesis in order and stop spending so much time on the web. Plus just built three flyrods and tying flies.

The figure that is used is from a paper from Paul Diodati and Anne Richards.

Diodati, P. and R. A. Richards. 1996. Mortality of striped bass hooked and released in salt water. Transactions of the American Fisheries Society 125: 300-307.

I feel that it was a very well done study and after I re-read it I'll post the highlights. They used some stripers as controls which is where some studies fail (because they don't use them). There was a more recent study by the Maryland DNR, but there is some debate over the study design (transferring fish from salt to the freshwater after hooking, lack of controls, mortality might have been associated with holding conditions - if I recall it correctly).

There appears to be a difference between freshwater and saltwater mortality figures, with the saltwater caught fish experiencing less mortality. Diodati and Richards estimated the mortality figure to be between 3-26%, with an overall figure of 9%. Other studies have estimated freshwater mortality to be 15.6% for artificials and 30.7% for natural baits (Harrell 1988), and mortality has been shown to be related to season, striper length and bait type (Hysmith et al. 1993). The fish (in Diodati and Richard's) were caught using only barbed hooks (if that makes a difference - another story) - using unbaited lures with 1-3 treble hooks, single-hook rubber jigs, or baited single hooks. Live seaworms or dead American sand lance were used for bait. Fish were caught by : casting from boats or shore (lures or jigs), trolling from boats (lures or jigs), or bait fishing from boats (single hooks). Hooks were always removed without regard to hooking location, or how deeply they were embedded. Playing time, handling time, depth of hook penetration in oral cavity, site of hooking, degree of bleeding and gear and individual tag number were recorded by a technician. The fish that had been hooked but survived showed a reduction in condition factor ([weight/length^3]*10,000) as compared to unhooked fish, as well as the "control" fish that were not susceptible to angling. The reduction in condition factor indicates that there is some negative effects (stress) from being angled. Angler skill level played a role in mortality, with more experienced anglers having lower mortality associated with their angling activities.

All of these fish were brought into the 2ha brackish pond (Cat Cove Marine Lab - Salem, MA) after being caught by a trap net operator in Newport, RI. The fish were allowed to acclimate for 50 days before angling began, and they assessed the mortality from netting, tagging, and transporting. 1015 fish were put into the pond. 2 weeks before angling began 20 fish were segregated and used as controls. The pond was closed to the public. The anglers used were volunteers, primarily from MA fishing clubs. Anglers were surveysed for level of experience and used their own gear.

Well I guess I summarized it and will not have to re-post.

I will say that I have witnessed some terrible handling of striped bass down at the mouth of the Merrimack. Fish don't breath too well in the air, and they certainly can't breath sand very well.

While I am on the subject of striped bass handling, I have sort of a pet peeve and that is the use of Boga Grips to lift the fish and hold it for weighing. I know many of you use it, but I think that there is the potential to damage the jaw musculature of the fish and potentially screw up it's ability to feed. I don't have any hard scientific data to back this up, just my own opinion (take it for what you will). The metal pinchers on the end do not spread out the weight of the fish, they are only 1/8th of an inch. I try to grab the fish by the caudal peduncle (base of the tail and by the jaw - that way all the weight is not concentrated on a small area. Well enough of the soap box.

Hey juro where do I send the money for the two-handed project?
03-10-2000 07:02 AM
juro
RE:Catch & Release Mortality

Going beyond the northeastern striper scene, the native steelhead fishery is another example of required release and concerns about mortality. The use of nylon mesh nets for landing these giant trout strips the fish's critical slime layer from the scales, and here multiple barbed trebles make a big difference - partly because of the time and effort required to free the fish, and partly because plugs are fished from boats and the fish are almost always brought into the boat to be dealt with flopping on the floor of the boat, in the mesh, etc. The fish's fate would be much different if a barbless single fly hook were gently lifted from the lip by a kneeling angler, and the fish never handled.

The ocean salmon fisheries off the Olympic Peninsula and British Columbia require barbless hooks in may regions. In my personal opinion is that releasing a fish without taking it from the water is the best means.

In rivers, there are words of experience in Bob Boudreau's article about catch and release. I especially am pleased to read about the high survivability rates achievable thru proper fish handling in his article.

My personal belief is that the use of barbless, baitless hooks and the release of the fish as close to (if not in) the water as possible is a recipe for high survivability of the gamefish I catch. If there are 50 idiots for every conscientious angler, perhaps we need to somehow educate and increase the ratio?
03-09-2000 08:05 PM
trutta
RE:Catch & Release Mortality

Hi ssully:
I believe you can still do serious damage with all those treble hooks. Especially so wit people that don't take care and just rip away. But, the stats I read on deadly injuries with plugs were surprisingly lower than I would have expected. I guess they do really rip lips though. I personally, haven't used anything but flies for many, many years. I would venture that bait fishing is still the worst in terms of mortality of released fish. They do swallow bait pretty fast.
03-09-2000 06:05 PM
timwatts
RE:Catch & Release Mortality

8% is probaly pretty close, for every guy who takes care with the fish another fifty do not. Another factor with a bunch of treble hooks is even if the fish doesn't get hooked deep it can take along time to get the hooks out. People step on them and and put them in a death grip around the belly. Then the fish flips around and re hooks itself and you start all over again. The release mortality rate is really disturbing according to the DMF almost 577 thousand stripers the average being 5.5 pounds were lost in 1998 through catch and release in massachusetts.
03-09-2000 05:49 PM
ssully
RE:Catch & Release Mortality

Just to throw in my .02

Greg may be correct in his assessment of the colateral damage caused to fish via bait(deep hooksets)and lures with multiple hooks ie. the 2&3 treble hook variety. Which definitely inflict unintentional peripheral damage.

I know unfortunately from past experience that fish I have caught and released with lures having multiple trebles caused eye and gill damage. Which may lead to the fish's early demise. Blind in one eye in an ocean of predators...

It is one of the main reasons I switched to jigs(single hook) and plastics for spin fishing. Plus having a few trebles buried in my hand.

And then the slob factor(uneducated/uncaring)fisherman who throws the fish overboard or tosses it overhand from the beach into the surf because it's a short.

Pete are you out there?
03-09-2000 10:06 AM
trutta
RE:Catch & Release Mortality

Gregg:
I'm not sure about the percentage but I recall reading something about plugs with multiple hooks (like several trebles). In this case the mortality rate due to damage to gills, etc, was minimal, I think, due to the fact that these trebles generally hooked the fish on the roof or lower jaw, hardly ever penetrating further. I mean, it'd be a miracle to get that many points and barbs passed the mouth and external areas without any of them hooking up.
03-09-2000 08:22 AM
Hawkeye
RE:Catch & Release Mortality

I don't know this for sure but I think that 8% number applys less to fly fisher types than to those who use multi-hook lures and bait fishermen. For those latter two categories I would be suprised not at all by the 8% figure.
03-08-2000 09:53 PM
Bob Pink
Catch & Release Mortality

The MFC hearings provided data that they are using as part of the analysis of the striped bass stocks. One key componet of this data is an assumed 8% mortality rate for bass caught & released. Since Mass has the bulk of the recreational catch and release, the figures they assume for a bycatch mortality are astounding.

Now, I know when you release a fish you can't be certain that it's in good shape. I am certain the clowns that flip them back into the water off a moving boat (recreational or charter) might be pushing that 8% figure but I just can't accept that 8 out of every 100 fish I land are dieing because of the stress of being caught.

Any marine biologists out there who have studied this? What's your opinion?

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