|Mortality and growth rates can be significantly effected... Should we allow it? |
Since some recent innovations in bait tackle and technique appear to reduce or eliminate the immediate mortality of released rainbow trout Oncorhynchus mykiss, this study tested the hypothesis that they are as effective for hook and release as artificial flies. Hatchery rainbow trout from aquaculture pens were caught using circle hooks, the new Shelton self-releasing hooks, standard J and treble hooks, and artificial flies (all barbless), noting hook location, 26-d weight change, and survival. Except for those caught on artificial flies, the fish were encouraged to swallow the hook, which was baited with a pasty attractant popular in eastern California (Berkley Powerbait). Most Shelton, J, and treble hooks (78, 65, and 63%, respectively) lodged in the esophagus, whereas all artificial flies and at least 70% of the circle hooks lodged in the mouth or jaw. Flies, circle hooks, and Shelton hooks were extracted from the fish, and the lines were cut on the J and treble hooks. The fish caught with flies, J hooks (line cut), and netted controls all survived the observation period. The survival of fish caught on the Shelton, cut-line treble, and extracted circle hooks was 98, 98, and 91%, respectively. The mean growth of cut-line J-hook fish was somewhat below that in other groups. The results from a second experiment showed that the Shelton hooks can be effective (0.7% mortality in 60 d) with no fish handling, and a third study suggested that much larger fish suffer only slightly greater mortality from flies, cut-line circle hooks, and Shelton hooks (0.7, 3.3, and 4.7%, respectively). Since significant differences in the long-term mortality and growth effects of some bait techniques and artificial flies could not be demonstrated, the use of the former should be recommended to anglers and perhaps reconsidered in waters where bait angling is not currently allowed.