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Ecological Shifts in Coastal Ecosystems Post-Cod Extirpation: Insights from Monhegan Island

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minna
13 diapositives · 266 Views · Jul 26, 2014

This research explores how coastal ecosystems in Monhegan Island, Maine, have transformed since the extirpation of Atlantic cod in the 1880s. Atlantic cod were significant predators, maintaining the structure of marine food webs through their high abundance and broad trophic roles. By examining archaeological evidence and historical data, we integrate ecological processes with past patterns, shedding light on possible shifts in species composition and ecosystem dynamics. Our findings aim to enhance the understanding of ecological changes linked to the loss of this keystone species.

#ecological shifts in coastal ecosystems post-cod extirpation: insights from monhegan island #ecological shifts in coastal ecosystems post-cod extirpation: insights from monhegan island ppt #powerpoint #presentation
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Ecological Shifts in Coastal Ecosystems Post-Cod Extirpation: Insights from Monhegan Island
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  1. Food Webs in the Wake of Atlantic cod • Present is not the key to the past • How might coastal ecosystems have changed since cod extirpation

  2. Monhegan I., Maine 1880s Knowable? (integrate ecological processes with historical patterns) What’s known and knowable about Atlantic cod? • They were big predators • Had broad trophic latitude • Were abundant • Lived in coastal benthic habitats • Strong interactors (controlled the structure of food webs)

  3. Fish hooks: 5,000 y bp Cod vertebra: 4,100 y bp

  4. 100 80 60 % Bone Weight 40 20 0 Cod Tomcod Sculpin Flounder Sturgeon ? Large ? Small Other Fish Species Fish bones in Indian “kitchen” middens 500 - 2,500 years ago Archaeological site in Boothbay Harbor, Maine Carlson 1986

  5. Coast of Maine

  6. The Turner Farm Penobscot Bay

  7. 40 30 20 10 0 Average percent fragments from all strata Atlantic cod Flounder total Sea mink Fish unidentified Winter flounder Softshell clams Swordfish Sculpin Sturgeon Yellowtail flounder Tomcod Harbor seal Seal (unidentified) Grey seal American dab 400 - 4500 ybp Dogfish Cunner Herring Blue mussel Haddock Halibut Pollock wolf fish Sand flounder Salmonids American Eel Sea urchin Harp Seal Alewife Waved whelk Quahod Carchardon (great white) Plocaena (porpoise) Cusk Balaena ( Right) Mackerel Bluefish Spies & Lewis 2001

  8. Proportion of Bone Mass Atlantic cod Flounder total Sea Mink Fish spp Winter flounder Softshell clams Swordfish Sculpin Sturgeon Yellowtail flounder Tomcod Harbor seal Phocid unidentified Grey seal American dab Dogfish Cunner Herring Blue mussel Haddock Halibut Pollock wolf fish Sand flounder Salmonid American eel Sea urchin Harp Seal Alewife Waved whelk Quahod Great white shark Porpoise Cusk Right whale Mackerel Bluefish 4350 4100 3550 1600 400 Years bp

  9. Proportion of Bone Mass Atlantic cod Flounder total Sea Mink Fish spp Winter flounder Softshell clams Swordfish Sculpin Sturgeon Yellowtail flounder Tomcod Harbor seal Phocid unidentified Grey seal American dab Dogfish Cunner Herring Blue mussel Haddock Halibut Pollock wolf fish Sand flounder Salmonid American eel Sea urchin Harp Seal Alewife Waved whelk Quahod Great white shark Porpoise Cusk Right whale Mackerel Bluefish 4350 4100 3550 1600 400 No lobster or crabs? Years bp

  10. Cod Size Over Past 4500 years 120 100 80 Atlantic cod body length (cm) 60 40 20 0 4500 4000 3500 3000 2500 2000 1500 1000 500 0 Years Before Present 5000

  11. Acadia National Park Fishing Grounds of Coastal Maine 1830 - 1880 (Goode 1887) Turner Farm Site

  12. Cod’s Prey 40 30 Crustaceans 20 10 Bivalvia Axiidae Gadidae Paguridae Clupeidae Cancridae Pandalidae Majidae Gastropoda 0 Other Pisces Ophiuroidea Scorpaenidae Amphipoda Other mollusca Other groups Sand and rock Other Crustacea Nereidiformia Animal remains Scombridae Echinoidea Other Polychaeta Other Decapoda Crangonidae Cephalopoda Other Echinodermata Euphausiacea Fish % Prey Echinoderms Sand and rocks! Langton & Bowman 1980

  13. 40 cm