Objectives
After participating in this activity, students will be able to:
- Explain why researchers study fish populations
- Describe techniques researchers use to monitor fish populations
- Describe the components of a GIS and other monitoring technologies
Summary
Scientists monitor the size, movement, and health of fish populations to better understand ecosystem interactions, manage sport and commercial fisheries, and help ensure biodiversity. Scientists use many different techniques to monitor Great Lakes fish populations.
Background
As discussed in Lesson 3, fish employ various strategies to reproduce and ensure survival of their own species. A group of individual organisms of the same species living in a particular area is called a population. Fisheries scientists study the size and movement of Great Lakes fish populations to understand ecosystem interactions. An ecosystem is a community of organisms interacting with one another and the physical environment.
If a fish population shows signs of stress, whether due to over-fishing, pollution, or habitat loss, scientists can pursue strategies to mitigate these factors. Some strategies might involve restoring critical fisheries habitat or implementing harvest restrictions. In this way, scientists help maintain Great Lakes biodiversity, or the abundance and variety of native species inhabiting the lakes.
Great Lakes fish populations are also closely monitored to meet fisheries management goals and ensure a sustainable fishery. The Great Lakes fishery is comprised of state and tribal commercial fishing operations and recreational fisheries. Accurate evaluation of fish populations helps fisheries managers establish equitable harvest quotas, set stocking levels for hatchery-reared fish, establish length and timing of fishing seasons, and help maintain a healthy predator-prey balance.
Studying fish populations often involves estimating the number of fish in a given population and tracking their movement. Fisheries scientists use different methods to do this. Some of these methods include GIS: Geographic Information System, GPS: Global Positioning System, Hydro-acoustics, and Mark-recapture.
To use these methods correctly, scientists must understand basic geographic concepts. Two of these are latitude and longitude. See glossary for definitions.
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