Understanding Apex Predator and Pelagic Fish Habitat Utilization in the California Current System by Integrating Animal Tracking With in Situ Oceanographic Observations; Technical rept

摘要

This study will develop a dynamic, ecosystem-based approach to map and understand habitat utilization by top predators in the California Current System (CCS). Oceanographic data will be obtained from both satellite imagery and the electronic tags which record environmental variables such as temperature, depth, light and salinity. Physical data obtained by tagged animals will permit comparison to features that are spatially and temporally concurrent with the animals foraging behavior. Consequently, the animal-derived oceanographic data will be used to define water habitat types based on hierarchical agglomerative cluster analysis on temperature and salinity profiles. Another approach that has been fruitful in the Pacific Ocean is to define thermal discontinuities based on changes in bathythermographs recorded by the tags between animal dives. These thermal discontinuities are then examined in relation to the rates and patterns of movement and fine scale behavioral changes of the diving animal. Large-scale habitat usage will be modeled based on individual animal utilization. One of the critical requirements in ecosystem-based resource management is learning how to define zones of high biological activity, or 'biological hot spots'. In the first phase of the NOPP grant, we will focus on automating routines that allow more rapid assessment of animal collected data and the habitat utilized by the tagged animals in relation to the surrounding oceanography.