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Behavioral changes in fishes and crabs in contaminated estuaries

Behavioral changes in fishes and crabs in contaminated estuaries. Predator/prey alterations could have consequences for birds Judith S. Weis Rutgers University. Collection Sites. Piles Creek (PC) Polluted Site - Linden, NJ. Great Bay-Mullica River Estuary (TK)

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Behavioral changes in fishes and crabs in contaminated estuaries

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  1. Behavioral changes in fishes and crabs in contaminated estuaries Predator/prey alterations could have consequences for birds Judith S. Weis Rutgers University

  2. Collection Sites Piles Creek (PC) Polluted Site - Linden, NJ Great Bay-Mullica River Estuary (TK) Cleaner Reference Site- Tuckerton, NJ

  3. Sites Piles Creek (PC) Polluted Site - Linden, NJ Surrounded by industrial sites, a sewage treatment plant, and a major highway. Elevated levels of organic contaminants and metals have been found in sediments and biota.

  4. Collection Sites Great Bay-Mullica River Estuary (TK) Cleaner Reference Site- Tuckerton, NJ part of the Jacques Cousteau National Estuarine Research Reserve, part of 3,500 acres of protected salt marsh.

  5. BACKGROUND • MUMMICHOGS (KILLIFISH, FUNDULUS HETEROCLITUS) FROM CONTAMINATED PILES CREEK ARE RESISTANT TO METHYLMERCURY, BUT RESISTANCE IS RESTRICTED TO GAMETES AND EMBRYONIC STAGES • AS ADULTS, THEY DO NOT GROW AS WELL OR LIVE AS LONG AS FISH FROM CLEANER ENVIRONMENT • ALTERED FEEDING BEHAVIOR MAY PLAY A ROLE – COMPARE FEEDING WITH THAT OF TUCKERTON (CLEAN) FISH

  6. FEEDING EFFICIENCY OF PC AND TK FISH PCTK X + SD X + SD STRIKES/PURSUIT 1.93 + 0.62 1.85 + 0.10 STRIKES/KILL 10.38 + 10.06 6.71 + 8.66 STRIKES/FISH/MIN 0.55 + 0.52 0.97 + 0.51* * P < 0.05

  7. NUMBER OF F. HETEROCLITUS EATEN BY BLUE CRABS OVER 14 DAYS ORIGIN OF FISH# EATEN#NOT EATENTOTAL PC 23 7 30 TK 12 19 30

  8. PREDATOR AVOIDANCE • COMPARE SURVIVAL OF PC AND TK FISH WITH BLUE CRAB (CALLINECTES SAPIDUS) PREDATORS

  9. NUMBER OF F. HETEROCLITUS EATEN BY BLUE CRABS OVER 14 DAYS ORIGIN OF FISH# EATEN#NOT EATENTOTAL PC 23 7 30 TK 12 19 30 More contaminated fish are more likely to be eaten by predator, and pass contaminants up the food chain.

  10. Blue Crabs- Callinectes sapidus Prey capture ability of adults from TK and contaminated Hackensack Meadowlands Compare predator avoidance ability of juveniles from TK and HM w. adult blue crab predators Jessica Reichmuth

  11. Capture of Juvenile Blue Crab Prey Adult Capture of Juvenile Blue Crab Prey Time to capture 2 of 4 juveniles Capture time (hrs)

  12. Capture of Mummichog Prey # mummichogs eaten

  13. Capture of Mussel Prey Capture of Mussel Prey Total Wet Weight (g) Eaten

  14. Capture of Fiddler Crab Prey Total # of fiddler crabs eaten

  15. Field: Stomach Contents HM Stomachs TK Stomachs

  16. HM Transplants to TK or fed clean TK food in the lab: Capture of juvenile blue crabs A B B Time to consume 50% prey (hrs)

  17. TK Transplants to HM or fed HM food (killifish) in lab: capture of juvenile blue crabs B C Time to consume 50% prey (hrs) A Reichmuth et al. ’09 Estuar Coast.

  18. Predator Avoidance Results Predator (adult Blue Crab) Avoidance by Juveniles Total # survivors

  19. Bluefish (Pomatomus saltatrix) studies: A temporary resident Spawn in the ocean and then move into estuaries in the spring. Spend critical periods of growth and development during first summer before going to the ocean for the winter What happens when they spend this first summer in contaminated estuaries? Allison Candelmo

  20. Trophic Transfer Experiments • Collect 60 YOY bluefish from Tuckerton in early summer as they enter the estuary • Feed frozen and live Brevoortia and Fundulus from either Hackensack or Tuckerton (control) for 4 months in the laboratory • Quantify feeding and swimming activity • Sacrifice fish and length and weight recorded • Analyze Laboratory bluefish for PCBs and Hg

  21. Feeding experiments after eating TK or HM food for 4 months TKfed - up to 5x faster Consumption rate TKfed - up to 2x more food consumed

  22. Swimming activity a b Poorer schooling – more milling about – would make them more susceptible to predation Candelmo et al. 2010 Est. Coasts

  23. Size Distribution

  24. PCB levels in mummichogs (Fh) and menhaden (Bt) from bluefish stomachs vs collected in nets

  25. Field Bluefish in Hackensack • Smaller than at Tuckerton in the fall when it is time to migrate back to the ocean • Most with empty stomachs • Contaminants like PCBs and mercury are biomagnified in bluefish over levels in their prey. • Fish with higher levels of contaminants are more impaired, more likely to be captured and transfer more contaminants to predators such as birds.

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