Chesapeake Bay Salinity Study: Fish Survival Analysis

1. Where in the Bay? By Pat Harcourt Waquoit Bay National Estuarine Research Reserve & Liz Duff Mass Audubon Special thanks to Kristen Ferry and Martha Mather for their Striped Bass Research in Plum Island Sound. Kristen Ferry Martha Mather

2. Many people are interested in striped bass, and have worked to support their species survival. Many fish populations are in decline due to overfishing.

3. Chesapeake Bay is one of the few places in the east where striped bass spawn.

4. They also spawn in Delaware bay, and in the Hudson River.

5. “Salinity” is how salty the water is. It ranges from 0 ppt(fresh) in lakes and rivers to 32-37 ppt in the ocean.

6. Salinity varies seasonally. Salinity Changes in the Chesapeake Chesapeake Bay Where is the Chesapeake the freshest (lowest salinity)? Where is salinity highest? How does salt water get so far into the Chesapeake Bay? Why do you think salinity changes seasonally? What changes do you see?

7. This salinity scale matches the colors on the map. 45 40 In Massachusetts, Ocean Salinity is 32-35 ppt. 35 30 25 Salinity in ppt 20 15 10 5 0 Fresh = 0-.5 salinity (no salinity)

8. 45 40 In Massachusetts, Ocean Salinity is 32-35 ppt. 35 30 Salinity in ppt 25 20 15 10 5 0 Fresh = 0-.5 salinity (no salinity) Salinity affects fish and other living things. Salinity Changes in the Chesapeake Many fish cannot live where it is too fresh or too salty. Some parts of the Chesapeake Bay are very salty (high salinity) others are nearly fresh (low salinity). Where do you think fresh water fish can range?

9. Instructions • Many fish cannot live where it is too fresh or too salty. Some parts of the Chesapeake Bay are very salty (high salinity) others are nearly fresh (low salinity). In this activity you will be placing a fish in parts of the bay with the right salinity for their survival. • Look at the table showing different kinds of fish and the salinity of the water they can live in. • Divide the fish in the table into three groups: those that can live in High, Low, and Both High and Low. Write each fish’s group on the line. • Choose tokens, or create a symbol to represent different fish species. For example, paper clips might represent low salinity fish. Using the spring salinity map, decided where to place the fish on your map of the Bay. For fish that can live in both high and low salinity, use two tokens of the same color in 3 areas of the Bay. • Make a key showing what fish is represented by each token/symbol. • Look at the fall salinity maps and move the fish if necessary. What fish had to be moved? How far did they move? • If you were going fishing, how would the salinity of the water affect your plans?

12. Chesapeake Bay Seasonal Salinity Map Where can the different species of fish live? Place them on the map.

13. Pause to do the activity

14. Answer Sheet

15. Seasonal Species distribution Answer Sheet Anywhere 0-30 low 0-8 0-15 0-12 Slide 10 high 12-30 15-30 12-30 Which fish species will probably never meet? Needlefish, bluefish, and sea horse probably never meet the brown bullhead

16. Part 2 Although striped bass can survive in all salinity levels, many striped bass migrate north in the spring to feed. Many of the young bass, called “schoolies” travel to the estuary in Plum Island Sound, on the north coast of Massachusetts to feed.

17. Striped Bass Migration Routes = Spring = Summer = Fall = Winter Boston (Specific return route is unknown) Hudson * Delaware * Chesapeake * MDMF 1998 People think that coastal bass migrate north to feed. Not every bass makes this journey.

18. As we learned, striped bass can survive in a wide range of salinities. (0-30) They can live throughout Plum Island Sound. Question: Will salinity affect the location of their prey species? Hypothesis: The distribution of striped bass will be impacted by the distribution of their prey. If salinity impacts the distribution of the striped bass prey, it will impact the distribution of the striped bass.

19. “Schoolie” striped bass in Massachusetts’ estuaries eat a variety of food. 4 3 2 1 Sand lance Mummichog River herring Silverside Shrimp Lobster ??? Menhaden Crabs Ferry & Mather

20. Plum Island Sound – Seasonal Salinity Map Spring (April 15, 1987) Summer (June 17, 1987) Winter January 7, 1987 Fall (September 17, 1987) Based on the ELMR data, Where do you think will schoolie prey be found? Design symbols to represent schoolie prey and put them on the maps. http://ecosystems.mbl.edu/pie/over.html

22. Answers

23. Salinity Distributions – Plum Island Sound Spring (April 15, 1987) Summer (June 17, 1987) Winter January 7, 1987 Fall (September 17, 1987) Lobster (8-36), menhaden (10-36) and sand lance (26-36) cannot go everywhere in PIS. Lobster Sand Lance Menhaden Their ranges in PIS increases in the summer and fall. Do you think this helps the striped bass? Show the summer and fall range for the sand lance. http://ecosystems.mbl.edu/pie/over.html

24. Part 3: Compare Salinity Tolerance of Schoolie Prey Adults vs. Juveniles On-Line. Check ELMR Estuarine Living Marine Resources web-site http://www8.nos.noaa.gov/biogeo_public/elmr.aspx Click on “North Atlantic” and choose the estuary and species you want. Click on the different salinity zones for each species. For fish, check adult and juvenile. For other species, such as crabs, just check adult. If it shows numbers other than zeros, it is present. If all zeros, it is not.

25. Example: There are zero adult lobsters at 0-0.5 ppt salinity.

26. Adult lobsters can be found at .5-25 ppt in the months of April through December.

27. Adults Names ____________________________

28. Juveniles Eggs What other questions can this data base help you answer? In your science journal, or on the back of this paper, list your questions. Choose one and investigate. Write down your question and its answer.