something to read ????
Barbless hooks: Do They Really Make a Difference?
I encountered an interesting scientific article recently regarding the difference in mortality between barbed and barbless hooks used in recreational fisheries. Dan Schill an R. L. Scarpella (1997) conducted a literature review and meta-analysis on all studies comparing the use of these two hook types, and came up with some very interesting results.
In the first study comparing barbed vs. barbless, Westerman (1932) concluded that barbed hooks caused higher mortality than barbless hooks, however, he did not use any statistical analysis to test these results. Since then, a number of different studies have taken place. Taylor and White (1992) summarized datasets from these studies using meta-analysis, and concluded that barbed hooks caused higher mortality than barbless as well.
Upon reviewing the Taylor and White review, Schill and Scarpella noticed that some previous studies were NOT included in the the analysis, and furthermore, the approach of statistical analysis in the review was questionable. They therefore decided to use a more common approach to the meta-analysis, and use all the existing available data up to 1997.
Using a more thorough data set and better methods of statistical analysis, Schill and Scarpella determined in 1997 that barbless hooks showed NO EVIDENCE OF REDUCING FISH MORTALITY IN COMPARISON TO BARBED HOOKS. Some studies did show higher mortality rates using barbed hooks, and others showed the opposite. However, the differences were so small (usually just a couple of percentage points) that they did not overcome the difference that could have been caused simply by random error.
Since the Schill and Scarpella paper in 1997, a number of other studies have examined the difference between barbed and barbless hooks. The results of all the studies I could track down are as follows:
Dubois & Dubielzig (2004) - showed no biological advantage in using barbless hooks
Dubois & Dubielzig (2004, different study) - no difference between barbed and barbless, except when fish deeply swallowed the hooks, in which case barbless were better.
Schaeffer & Hoffman (2002) - no significant difference in mortality between barbed and barbless. Barbed hooks landed 22% more fish. Quicker hook release time with barbless.
Meka (2004) - higher injury rates with barbed hooks, however she did not compare mortality, so results are not applicable.
Clearly, there has been no demonstrated evidence that barbless hooks cause lower mortality rates than barbed hooks. However, barbless hooks are becoming a more and more popular regulation in recreational fisheries. Why is it that these regulations persist? Even in Idaho, where Schill and Scarpella demonstrated the facts, barbless restrictions exist in many waters. I believe that the barbless regulation is simply a feel-good regulation. People are still convinced that barbless hooks “must” be better than barbed, despite what the science says.
Simply put, a mouth hooked fish, handled properly, has a very miniscule chance of dying whether or not the hook used is barbed or barbless. Mortality issues arise when the hook is swallowed and significant bleeding and tearing occur, as well as when a fish is improperly handled and held out of the water for too long. Therefore, we should quit worrying about the little barb that helps anglers land more fish, and start thinking about ways to improve other facets of angling mortality, particularly how we handle the fish once caught.
One final note: Schill and Scarpella quote the annual estimated NATURAL mortality of trout in streams to be between 30% - 65%. With such an incredibly high mortality rate already occuring, most fishing mortality is probably compensatory (the fish would have died naturally by the end of the year, whether or not you killed it). Therefore, how can we be justified in griping about a 0.3% mortality difference between barbed and barbless hooks?
This entry was posted on Sunday, June 10th, 2007 at 12:51 pm and is filed under Fishing Regulations, General.
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