Fishing tools are very widespread in the world’s fisheries and are used both in commercial and recreational-sport fishing. The problem with fishing tools, like most other tools, is that they catch non-target organisms in addition to the target ones. Caught non-target organisms, if they have not swallowed the hook, can often be detached and returned to the natural environment. In some countries, it goes so far that the entire catch or most of the catch must not be kept, but must be returned to the natural environment as soon as possible. This is the basis of catch and release fishing. However, sometimes the object of the catch swallows the hook, which cannot be removed without damaging the catch.

The hooks used in this study are standard in every respect except for one addition, which is a spike that prevents deep hooking of the fish. The use of this type of hook would potentially result in a reduction in the amount of unwanted catch, better survival of unwanted individuals returned to the sea, and thus would reduce the negative impact on the environment. In the world literature, there are very good indications and initial results that point to the great potential of longlines equipped with innovative hooks with a breakout, and for the Croatian fishery it is necessary to carry out systematic testing in the real environment to achieve optimal results, and to issue recommendations for the industry.