Impact of fisheries discards on foraging strategies of Atlantic bottlenose dolphin: A comparison of fitness and neural network based movement models

The objective of the study is to evaluate the potential impact of fishery discards on the foraging strategies of Atlantic bottlenose dolphins (Tursiops truncatus).  Can bottlenose dolphin obtain enough energetic resources from discards that adopting a strategy based on following human activity (i.e. fishing) is more profitable than traditional foraging strategies?  In the model we track hourly growth, movement, reproduction and mortality.  We compare four feeding strategies including: traditional search and forage, tracking fishing vessels to forage on discard, and two mixed strategies where either prey resources or discards are supplementary.  We performed 50 year simulations for each foraging strategy while simulating movement as either: 1) fitness-based or, 2) neural network (ANN).  Preliminary results show that fitness-based movement rules allow dolphin to take advantage of discard resources to sustain individual growth, and that population abundance and biomass depends on the size of the search radius, the ability to detect vessels, and the frequency of simulated fishing trips.  The ANN movement is in the development and testing phase.  We hypothesize that mixed foraging strategies will optimize individual growth and population abundance and growth for both fitness-based and ANN movement models.