Figure 1. A researcher holds the stomach of a juvenile sportfish taken so that stomach contents prey species can be analyzed. Traditionally, fish stocks have been assessed and managed as independent populations, however, marine researchers recognize that fish populations interact with each other, often competing for resources or in predator-prey relationships.
These interactions are complex and vary across ecosystems, age ranges, and habitats. Therefore, moving towards a more holistic, ecosystem-level understanding of fish populations for subsequent management requires significant work to determine what fish are eating and how their diets shift through their growth and across different habitats.
The goal of the trophic ecology lab is to provide quality diet data to understand these competitive and predator-prey dynamics.
Fish are collected in routine monitoring or opportunistically and the stomachs are removed for analysis in the lab Fig. There, our taxonomists use microscopes and dichotomous keys to identify all the prey to the lowest possible taxonomic level and obtain volumetric measures and counts of each.
Fish are often quickly digested and distinguishing species in stomachs without color, scales and fins, compared with other more easily identified organisms with hard parts, e. Often, fish jawbones and teeth are some of the last parts to be digested and remain distinguishable in stomachs.
