Tracking Summer Flounder in an Estuary Creek

Tracking Summer Flounder in an Estuary Creek: A WebQuest for 5-8th Grade (Biology)

Designed by Mary Olswang

In this Lesson Plan:

Introduction: For the Student

Age-0 summer flounder, Paralichthys dentatus were tagged and tracked at Schooner Creek, a sub-tidal creek located in an estuary in Southern New Jersey. Stationary and mobile hydrophone systems were used to monitor fish movements. Data were accumulated over a one- month period. Your job as a young scientist is to analyze the data, draw some conclusions regarding the use of the creeks in the estuary by juvenile flounder, and make recommendations to local officials who are considering designating the area as a reserve.

The Task

How important is the estuary creek habitat for the growth and survival of juvenile summer flounder? Over-population near the Jersey coast and non-point source pollution may be affecting this habitat. Previous studies have shown that important nursery areas within southern New Jersey estuaries are marsh creeks, where Age-0 summer flounder forage and grow quickly during summer before migrating out to deeper water in the fall. Scientists have been hired to collect data by tagging and tracking Age-0 summer flounder during late summer/early fall. The data were collected and put into spreadsheets and graphs. Your task is to:

  • Research

  • Analyze

  • Organize into research paper with conclusion

The Process

Working individually you will:

  1. Research the Jacques Cousteau National Estuarine Research Reserve

  2. Research the biology of Paralichthys dentatus, or summer flounder (two sources)

  3. Explain the tagging/tracking method used, how the data was collected and complete the map of the study area

  4. Analyze the data collected to draw conclusions about creek use and movements of the flounder

  5. List reasons (economic, biological or political) as to why it is important to protect the sub-tidal creek habitat in a reserve system

  6. Organize 1-5 into a research paper

Task One. The JCNERR

To Think About:

In this section you will use www.crssa.Rutgers.edu to view a map and learn about the Jacques Cousteau National Estuarine Research Reserve (JCNERR), which is home to one of the largest estuaries in the NERR system. As you are navigating through, consider these questions: Why are estuaries so important? What is unique about this one?

The Task

  • Go to >the Gallery section for the JCNERR.

  • Click on the "Maps" link.

  • Five maps are thumb-nailed, the one furthest to the right is a satellite image of Tuckerton-Little Egg Harbor

  • Download a PDF or JPG version of the map, so that you are able to zoom in

  • Find the Rutgers University Marine Field Station (RUMFS). Save the image for your paper in a file

  • Go back to the Gallery

  • Click on "Links"

  • Click on "Jacques Cousteau National Estuarine Research Reserve (main site)" to get to the JCNERR main menu.

  • Click on "About JC NERR"

  • Click on "Description of JC NERR"

  • Scroll down to Geology

  • Click on the picture on the right to see the many tidal creeks of the estuary

The Questions

Visit this site a little longer to read about and see all of the components in the reserve, then try to answer these questions:

  • Can you think of three reasons why estuaries are important areas along our coast?

  • How does one component of the reserve affect another?

Task Two: Research the biology of Paralichthys dentatus

To Think About

You may be asking: So what's the big deal about Summer Flounder? Remember, you are young scientists with a mission. In this section, you are going to do some research to learn more about them. Some questions to consider as you research the Summer Flounder: Which parts of the estuary do they frequent and why? In what ways are flounder prepared and consumed by humans?

The Task

  • Go to www.FishBase.org.

  • Search FishBase

  • [Genus] Paralichthys

  • [species] dentatus

  • Right-Click and save the picture of the flounder for your paper or find a different one.

  • Click on "Pleuronectiforms" for more information about this family.

  • Go back out to the species summary

The Questions

Under "More information," click on "Larvae" and other sections to learn more about this species. Then try to answer the following questions:

  1. What are two adaptations this order of fish has made to the environment?

  2. What are some challenges in this environment?

Task Three: The method, the data and a map

To Think About

For this portion of the process, you will read the following sections about the study as well as the study area. Keep in mind that you will print out the image below and draw in some points of detail. Eright-click on the image to save it or copy it to another application.



Where the study was done and why

Schooner Creek is a salty tidal creek that runs along side the JCNERR field station in the estuary. It was chosen as the site for this study because in a past tagging study at this site, large gaps of time left several unanswered questions regarding when the fish left and the extent of their creek use. The creek was divided into five sections based on depth and width, but we will be looking at three:

  • Mouth: the first 50 meters from the creek mouth (0 meters)

  • Flat: a shallow flat area just inside the creek mouth (less than 0.2 meters deep at low tide, 50 to 150 meters up from the mouth

  • Upper creek: the creek area above the stationary hydrophone which is located at 150 meters on a point of land

Now you can begin filling in points on your map, starting with the mouth, flat, upper creek, and the stationary hydrophone.

Tagging

Five summer flounder were captured using fyke (funnel type) nets approximately 150 meters up the from the creek mouth. Four were captured using hook and line near the tide station, which was approximately 350 meters up from the creek mouth. All nine of the fish were determined to be less than one year old based on information about size and age. (Here is some more information for your map.)

They were tagged and released at different times. Each fish was temporarily put to sleep with an anesthesia and an ultrasonictransmitter was attached with a strong thin thread by sewing through the muscle just below the dorsal fin. The transmitters were manufactured by Sonotronics, Tucson, Arizona, weighed 4 grams in the air and had a 40-day life expectancy. So, there were 40 days, or about a month and 10 days to collect the data. It was the beginning of August.

Since it wasn't known how the fish would recover from the tagging procedure, they were kept for observation in a flow-through seawater tank for about 1-48 hours. The release site was approximately 530 meters up the creek from the mouth. The tagging-release procedure began August 9, with the last fish tagged and released on August 27th. Fish movements were tracked until the last signal was lost on Sept. 27, 1990.

Tracking

A 150-meter coaxial cable connected the hydrophone to a continuously scanning receiver. After a signal is detected from a tagged fish, the tag number, time, and date were stored in a computer. After some testing, it was determined that the stationary hydrophone was good for approximately 130 meters directly in front of it. Sometimes a fish would swim back and forth in front of it making multiple detections, so multiple detections within 5 minutes were counted as one. The other way fish were tracked was by portable directional hydrophones from a small boat or kayak. Initial detection was recorded on a detailed map of the creek. Then the creek was searched every six hours during slack water. Slack water is the time just before a high or low tide when the current is minimal.

If a fish had not been detected for a while, a search was on dividing the mouth and a short distance beyond in 1 KM transects or grids from the last known location. Transect searches were repeated three time before the signal was considered lost.

A "missing" category accounted for the time it was known the fish was in the creek but could not specifically locate it. For example, if a particular fish was located at the mouth at 6:00am and in the upper creek at 12:00 pm, but did not detect it moving up the creek, 6 hours were placed in the "missing" category.

Each time a fish was detected by the portable hydrophone, the time and stage of the tide was recorded as well as some physical and chemical data. The tide station was located 335 meters from the creek mouth. Surface salinity was measured with a refractometer, bottom temperatures and dissolved oxygen (DO) concentrations with a YSI meter.

Important Note: you are going to have to explain what these things are when explaining your data

The Questions

Now that you have a better understanding of the study and it's whereabouts, answer the following questions:

  1. Why do you think they only tagged nine fish?

  2. Do you think the creek was a large enough study area?

  3. What are some challenges in choosing this tagging and tracking method?

  4. When did they track using the portable method? Why?

  5. Where was the stationary hydrophone and in what direction was it pointing?

  6. What is "missing time?"

  7. What is a refractometer?

Task Four: Analyze the data and draw conclusions

To Think About

In this section, you are to read and interpret the resulting data from this study. Keep in mind that you'll be using this data.

Click on the thumbnails below to view and download the data sheets that scientists produced from this study:

Mean dissolved oxygen levels, salinity and water temperature data.

Charts demonstrating the amount of time spent in each location.

The Questions

  1. What information does the data provide?

  2. Where did the fish spend most of their time and why?

  3. What do you think happened to fish A,C,F,H?

  4. What is "mean" DO, Temperature and Salinity?

  5. What property/properties of water would cause the fish to move?

Task Five: List reasons to protect

Now use your data and the information you gathered about the flounder and the estuary to present your argument for designation as a research reserve. Think about this question as you are compiling your list: What steps can we take as responsible stewards on planet earth to be sure that this habitat is healthy and available to future generations of fishes?

Task Six: Your Paper

Your paper must be three to five pages long and include the following:

  1. Introduction: Research Question- State the question your research will answer

  2. Background Information about the estuary and P. dentatus

  3. Methods: Describe the study methods

  4. Results: Data goes here

  5. Discussion: discuss the data and draw conclusions

  6. Literature Cited

Be proud of your work! Make it neatly typed and thorough.

Evaluation

The maximum points you can earn on the project are 120 to be beyond awesome. There are three sections in the scoring rubric.

Lesson Evaluation

 

1-10: Not So Good

11-20: Getting There

21-30: Great Job

31-40: Beyond Awesome

Individual Research Notes with Task Questions

Notes are cut and paste copies from website. No questions answered.

Notes have some organization. Reflect original writing. Some questions answered, some difficulty understanding.

Notes are organized, original writing. Source notations cited. Most questions answered with some understanding.

Notes are organized. Original writing. Source notations. All questions answered with complete understanding.

Discussion of data

Didn't discuss the data very much.

Graphs and charts analyzed and conclusions attempted.

Graphs and charts analyzed and concise conclusions discussed.

Graphs and charts analyzed in detail. Was able to mingle data with questions answered during the tasks.

Paper

Sloppy. Very little content that was required. No charts or graphs.

Charts, graphs, map included. Lacks some background information.

Charts. Graphs, map, background information included. Conclusion and recommendation attempted.

Charts, Graphs, map, background information. Conclusion and recommendation well thought out.

Conclusion

The salt marsh is a very dynamic environment, yet many species of fish use its creeks as nurseries. Young fish need this unique habitat to grow before venturing out into the ocean. What steps can we take as responsible stewards on planet Earth to be sure that this habitat is healthy and available to future generations of fishes?

Credits and References

Szedlmayer, S.T. and Able, K.W. 1993. Ultrasonic Telemetry of Age-0 Summer Flounder, Paralichthys dentatus, Movements in a Southern New Jersey Estuary. Copeia,(3), pp. 728-736

Last updated on August 15, 1999. Based on a template from The WebQuest Page



 

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