Reflex Impairment Tests

There was a question regarding reflex impairment tests. This is a relatively new concept that was developed on the West coast by a biologist working with fish species caught as by-catch. He found that some of the species caught as by-catch did not display certain standard reflexes as a result of the commercial netting taking place, and he was later able to trace these reflex impairments to mortality.

Each fish species has its own set of unique reflexes, but there are some that can be applied to most (e.g., does the fish have equilibrium?). Some of these reflexes include dorsal fin erection, the gag reflex, mouth and operculum (gill plate) closure when gently pried open, body flex upon restraint, whether the fish has equilibrium, vestibular-ocular rotation (do the fish's eyes follow you as you rotate the fish along its longitudinal axis?). The aforementioned reflexes are typically done with the fish restrained. We are using all of the above except for the first two. Also, some reflexes can be done with the fish "free-swimming". These include whether the fish bursts away upon release and whether it swims downward upon release. We are using these tests as well.

Some might ask, "So what?" These reflex impairment tests are pretty cool as ANYONE can do them. It is our goal to try and validate them as good indicators of fish stress and survival. If we can do so and show particular reflexes may be correlated with stress and survival, these can be easy "field checks" that anglers can do to assess the condition of their catch. By doing so, it may be possible for the angler to evaluate how their handling may be affecting the fish. Ultimately, if an angler sees a pattern in their handling practices that appears to be detrimental to the fish (based on the reflex impairment tests), they may be able to change their (the angler's) behavior, change their handling practices, and increase the survival of future catches.