Academic journal article The American Biology Teacher

Move over! Studying Flatfish Travel Patterns to Profile Fish Behavior

Academic journal article The American Biology Teacher

Move over! Studying Flatfish Travel Patterns to Profile Fish Behavior

Article excerpt

Important information about an animals life and ecosystem can be ascertained by the way it moves from place to place. Key factors regarding how and why certain animals change location include the need for food, protection from predators, and reproduction. Environmental factors must be considered as well, including food quantity, presence of shelter, and temperature. Not all fish species migrate, and there are large potential costs to migrating. Migrating organisms are exposed to unfamiliar areas that may have more or different predators. Studying animal movement therefore leads to a broad consideration of the survival strategies of a species.

Tracking animal movement can be difficult, and understanding travel patterns of marine organisms presents the particularly daunting challenge of mapping underwater movement. For commercial species, considerable information is collected by fishermen. Visual underwater census counts are possible for some species, especially shallow-water reef fish such as angelfish, as well as certain benthic crustaceans and mollusks (Paddack & Estes, 2000; Samoilys & Carlos, 2000; Hereu et al., 2008; Kendall et al., 2009). It is even possible to conduct visual surveys using submersibles or remotely operated vehicles for deeper-water fish (Willis et al., 2000; Yoklavich et al., 2007). Tagging fish with darts, coded wire tags, or acoustic transmitters is becoming more common and can provide information not only on long-distance migration patterns but also on fish growth (Holland et al., 1993; Heupel et al., 2006; Holm et al., 2007). Finally, species abundance can be estimated through sampling by trawl nets, and data on fish movement into and out of a region can be obtained by repeated trawling of a given area (Pihl, 1989; Cabral et al., 2007).

Here, we present actual data collected from repeated trawls of Wylly Creek, a shallow tidal creek in Savannah, Georgia. The objective of the research is to profile the use of a shallow estuarine tidal creek by flatfish species. Flatfishes are intriguing animals that undergo extreme metamorphosis. Many species, such as southern flounder and halibut, are important sources of food. In this middle school lesson, students review the data set and infer what it tells us about the behavior of different flatfish species. On the basis of these data, students discover that even though flatfishes are members of the same taxonomic order, they move into and out of a tidal creek in different ways. Students then use a map of the area to plot an example of the distance traveled by a particular species of flatfish, the southern flounder (Paralichthys lethostigma), and calculate the relationship between this distance and the size of the fish. The resulting distance-to-body-length ratio is then multiplied by the student's average step length, so that a comparable estimate of how far a human would have to walk to mirror the southern flounder's movement is determined. This exercise demonstrates how far these fish travel, considering their small size.

In addition to learning about animal movement patterns, students will also become more ocean literate. A recent definition of ocean literacy was developed through a consensus-building process involving many marine science and educational organizations, including the National Geographic Society, the National Oceanic and Atmospheric Administration (NOAA), the Centers for Ocean Sciences Education Excellence, and the National Marine Educators Association (Cava et al., 2005). This lesson on flatfishes addresses Principle 5 of Ocean Literacy (The ocean supports a great diversity of life and ecosystems), Concept j: Coastal estuaries (where rivers meet the ocean) provide important and productive nursery areas for many marine species.

Background

Flatfishes are bottom-dwellers with particular adaptations for life spent lying on or in sand or mud. Their bodies are flattened, with oval or elongated shapes. …

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