Why observe several reflex actions together to measure animal vitality? The short answer is that animals are whole beings; a summary collection of component parts and their interactions in response to stimuli.
Animals are constructed of biochemical and behavioral components that interact to form a whole; capable of responding to stressors. The interactions of stressors and behavior are also important for prediction of vitality impairment and survival. Reflex actions are fixed behavior patterns that include biochemical, muscle, organ, and nerve functions.
Efforts to identify factors that can control vitality and predict post-release survival and mortality of captured animals generally strive to identify single important variables. For example, temperature changes, injury, exhaustion, and hypoxia can control vitality and survival. For simplicity, single factors are statistically modeled as predictors for survival. Factor interactions are rarely considered because of their complexity.
Patterns of vitality impairment vary with species and contexts. Observing impairment of several reflex actions and possible injury in a defined context integrates the effects of multiple stressors, contexts, and their interactions on animal impairment and survival. Measurement of single reflex action impairment can miss the range of vitality that spans from excellent to moribund.
Stoner 2012 (crabs)
Below are several examples of the cascading nature of impairment observed as individual reflex actions cease to function in a spectrum of stressor intensities. Reflex actions with higher proportion of impairment are impaired before those with lower percentage. Note that patterns of impairment vary with taxa and context.
Davis 2010 (walleye pollock, coho salmon, northern rock sole, Pacific halibut)
Stoot et al. 2013 (turtles)
Uhlmann et al. 2016 (plaice, sole)
Forrestal 2016 (triggerfish)
Forrestal 2016 (yellowtail snapper)
Danylchuk et al. 2014 (lemon shark)
McArley and Herbert 2014 (snapper)
Sampson et al. 2014 (mottled mojarra)
Stoner 2009 (Tanner crab, snow crab)
Stoner 2012 (spot prawn)
