Wen-Miin Tian / National Sun Yet-sen University (retired)
A mixed Eulerian-Lagrangian and quasi-optical approach based on a single acoustic apparatus was developed, which allowed simultaneous extraction of information from acoustic backscatter on fish within water (position and morphology) and bottom habitat (relief and substrate) to fulfill the knowledge requirements of Ecosystem-Based Management (EBM) through mechanistic evaluations. The proposed procedure incorporated three major technological/methodological components:
1. Image Acquisition:
2. Information Quantification (From image to information):
3. Knowledge Characterization (From information to EBM knowledge):
The small wetland pond under investigation spans limited and isolated spatial area (i.e., 55mx55x2), enabling measurement of location and morphology of fish individuals without the confounding effects caused by immigration/emigration processes. Ecosystem characteristics of the wetland pond indicated a single food chain based on phyto-plankton production and predator-prey interactions. Other prominent conclusions included: Diffusion-reversion-advection and CCW circling movement pattern as well as population dynamics; Overlapping of predator (snakehead fish) and prey (tilapia dominated) interactions; The predators tend to attack the prey from behind by ambush or chasing predation activity, the attacked school/shoal often spreads out or splits into small groups: Saturated environmental carrying capacity based on community distribution status; Weakly exploited snakehead fish population and greater nutrient inputs system for tilapia based on population structure.