The beginning of RAMP

I was researching the effects of capture and release of non-target commercially important fish species, commonly know as bycatch. The research was aimed at understanding what happens to fish when they are captured in commercial fishing gear and then released because of fishing regulations. The question is important because fish that are stressed by capture and release often show delayed mortality and this source of mortality is difficult to measure and account for in management of fish stocks.  Results of this research were summarized in an article published in 2002.

Because delayed mortality cannot be observed directly, some kind of measure of the animal's vitality prior to release needs to be developed for prediction of delayed mortality. Our team tried to relate blood plasma variables, measures of physical injury, and complex voluntary behavior with delayed mortality. However these measures were not correlated with immediate or delayed mortality.  

One day while watching fish recover after exposure to simulated fishing capture, I began to think about the fact that the intensity of fish involuntary behavior after capture appeared to be negatively related to the intensity of the capture stressor. Fish subjected to more intense capture stressors became more lethargic and their involuntary behavior was more impaired. These involuntary activities are known as reflex actions and represent fixed involuntary actions that occur in response to external stimuli such as gravity, bright light, loud sound, or touch. The reflexes can be part of important behavior such as startle, orientation, predator avoidance, feeding, migration, and sex.

So I decided to measure and quantify reflex actions and to try to correlate impairment of these actions with delayed mortality. This idea of measuring a suite of reflex actions and correlating the measure with mortality was very successful and I called it RAMP - reflex action mortality predictor. The development and deployment of RAMP is described here, here, and here.

Since that original work, other researchers have used the RAMP approach to quantify stress and predict delayed mortality in a variety of fish and invertebrate species. I will describe their work in future posts.