In days gone by, catch and release was a term used for anglers who's line broke before they could get the fish in the creel. Times have changed and fisheries management is an established part in today's recreational angling world. With this management has grown an increased awareness for conservation, by many more fishermen. One of the key behaviors to arise from these conservation measures, is the concept of catch and release, which is becoming more the norm.
When one discusses catch and release, the topic of barbed vs barbless hooks and the effect on fish mortality
is inevitable. Arguments will spring up quickly with this topic, and this seems to be due to the limited amount of research that has been done in this field. It is an important area of study, as delayed mortality from catch and release is extremely important in the development of fishing restrictions and regulations toward an effective management strategy.
To get a better understanding of this subject I decided to review some of the scientific literature to determine what the science was indicating, and leave the speculation to the armchair biologists, like myself. I must admit that I was surprised by what I discovered.
Most of the studies involve comparing the mortality rate between fish of similar species hooked and released with barbed and barbless hooks. The literature does indicate that
mortality rates can be varied between species, but that within a species, the use of a barbed versus barbless hook is considered insignificant at best. Most fishermen know that some species are as tough as nails and survive despite rough handling, while others die just by looking at them sideways.
One study, by Schaeffer and Hoffman, documented that 22% less fish were landed with barbless hooks, so it does appear that the fish can more easily throw a barbless hook. This is also reported in other studies. If your fishing activities lead to significant financial rewards, it could be argued that barbless hooks are an unacceptable risk. For the recreational angler, this number could be reduced by improved technique, and may in itself be an acceptable loss.
What also came out of these studies, is that the anatomical hooking location is one of the prime determining factors for catch and release mortality. Other factors included : use of natural bait, j-hooks vs circle hooks, extended playing and handling times. The aforementioned study did suggest a marginally higher mortality rate for barbed hooks.
Some reports did mention that the removal of
a barbed hook, can increase tissue damage and more bleeding than with barbless hooks, which is pretty obvious. This also means that fish will be out of the water longer. So the handling here and not the hook, may be more of a contributing factor. It would seem that use of barbless hooks can help reduce mortality to a very small, and almost insignificant degree, but is only a small percentage of the factors one needs to be aware of when practicing effective catch and release.
Bait fishing, which tends to be done with barbed hooks, usually results in hooking deeper in the throat which is a far bigger problem in itself, than the barb. Fishing with artificials usually results in lip hooking, where the barb has little effect on mortality. When bait fishing, it does appear that circle hooks have a definite advantage in this regard, over J-hooks.
When it comes to overall catch and release mortality, and even delayed mortality, there appear to be numerous factors involved beyond the hook type. The overall handling of the fish is what is critical to it's survival. If the fish is being hooked in the lip by a treble barbed hook, the literature is indicating that this is way less traumatic than being throat hooked by a barbless hook. Barbless hooks may only be helping us feel better about catch and release, and doing very little for the fish. Like so many other aspects of our life, feel-good decisions sometimes trump solid scientific analysis.
Some of the waters around my home are restricted by the Fish and Game Department to single hook, barbless only. I am now beginning to question what scientific studies they are basing this tough-to-enforce decision on.
Personally I still think the best reason for using barbless hooks, is that they are much easier to remove from an earlobe, nostril or finger.
So next time you see a kid fishing with a worm on a barbed hook, don't yell at him about the barb, give him a lure or a fly. That's going to help the fish a lot more.
References:
Barnhart, RA (1990). Comparison of steelhead caught and lost by anglers using flies with barbed or barbless hooks in the Klamath River, California., California Fish and Game. Vol. 76, no. 1, pp. 43-45.
DuBois, Robert B; Dubielzig, Richard R (2004). Effect of Hook Type on Mortality, Trauma, and Capture Efficiency of Wild Stream Trout Caught by Angling with Spinners, N. Am. J. Fish. Manage. Vol. 24, no. 2, pp. 609-616.
Schaeffer, JS; Hoffman, EM (2002). Performance of Barbed and Barbless Hooks in a Marine Recreational Fishery., N. Am. J. Fish. Manage. Vol. 22, no. 1, pp. 229-235
Butcher, Paul A. Broadhurst, Matt K.; Brand, Craig P. (2006) Mortality of sand whiting (Sillago ciliata) released by recreational anglers in an Australian estuary. ICES Journal of Marine Science 63 (3) : 567-571
Most of the studies involve comparing the mortality rate between fish of similar species hooked and released with barbed and barbless hooks. The literature does indicate that
mortality rates can be varied between species, but that within a species, the use of a barbed versus barbless hook is considered insignificant at best. Most fishermen know that some species are as tough as nails and survive despite rough handling, while others die just by looking at them sideways. 
Bait fishing, which tends to be done with barbed hooks, usually results in hooking deeper in the throat which is a far bigger problem in itself, than the barb. Fishing with artificials usually results in lip hooking, where the barb has little effect on mortality. When bait fishing, it does appear that circle hooks have a definite advantage in this regard, over J-hooks.