science behind sustainable seafood solving the ecosystem problem alaska fisheries science center
TRANSCRIPT
Science Behind Sustainable SeafoodSolving the Ecosystem Problem
Alaska Fisheries Science Center
What is the effect of removing a primary food source in Alaskan waters?
2
Organisms are interconnected by what they consume.
Free write
• Write down what comes to your mind when I say the word food web.
• Underline three things you wrote which are important to a food web
http://www.afsc.noaa.gov/REFM/REEM/Manuals/Default.htm
Krill video
• http://video.nationalgeographic.com/video/animals/invertebrates-animals/crabs-lobsters-shrimp/krill/
• What animals ate krill in the video? • Describe a food chain they saw in the video• How does a food web differs from a food chain?
http://jonbowermaster.com/blog/2009/01/krill-baby-krill/
Parts of the Bering Sea ecosystem• The sun’s energy is converted into nutrients for plants through
a process called photosynthesis.
• Phytoplankton are microscopic plants that drift in the ocean. They are at the base of all food chains in the Bering Sea
• Zooplankton are microscopic animals and are found near the bottom of the Bering Sea food chain. • Zooplankton like amphipods and copepods are prey to
many small fish.• Big baleen whales eat zooplankton (Humpback whales)
Parts of the Bering Sea ecosystem• Small fish like herring and juvenile walleye pollock can be
both predator and prey since they sit in the middle of the food chain.• Feed on zooplankton
• Adult walleye pollock can also be both predator and prey. they are not the top predator. • Feed on krill and juvenile pollock
• Humans are at the top of the food chain.
• In the Bering Sea, northern fur seals are also a top-predator• Feed on walleye pollock, Atka mackerel and Pacific cod
Stomach data• To better understand the relationships between predators
and prey in the Bering Sea, scientists at the Alaska Fisheries Science Center annually collect and examine the stomachs of thousands of fish.
• What they see tells them a lot about how important all species in the Bering Sea are to maintaining balance within the entire ecosystem.
http://www.afsc.noaa.gov/REFM/REEM/Manuals/Default.htm
year 1999
stomachs 2839
hauls 164
Prey name Percent weight
zooplankton 56.96
pelagic invertebrates 4.34
squids 2.24
forage fish 8.45
flatfish 0.44
rockfish 5.5
other fish 5.62
pollock 2.19
benthic invertebrates 4.06
shrimp 14.47
crab 0.54
glopp 0.69
Sum 105.5
Walleye Pollock
WALLEYE POLLOCK STOMACH DATAhttp://www.afsc.noaa.gov/species/pollock.php
year 1999
stomachs 1401
hauls 136
Prey name Percent weight
zooplankton 3.94
pelagic invertebrates 0.41
squids 0.74
forage fish 2.73
flatfish 6.79
other fish 9.4
pollock 24.29
cod 0.72
arrowtooth 0.02
benthic invertebrates 14.11
shrimp 6.99
crab 29.21
glopp 0.64
Sum 99.99
Pacific cod
PACIFIC COD STOMACH DATA
http://www.afsc.noaa.gov/species/Pacific_cod.php#
year 1999
stomachs 148
hauls 39
Prey Name Percent Weight
zooplankton 8.47
forage fish 4.47
flatfish 0.05
other fish 16
pollock 60.4
benthic invertebrates 1.16
shrimp 5.91
crab 3.51
glopp 0.02
Sum 99.99
Arrowtooth flounder
ARROWTOOTH FLOUNDER STOMACH DATAhttp://www.dfw.state.or.us/MRP/finfish/sp/flatfish.asp
year 1999
stomachs 232
hauls 38
Prey Name Percent Weight
zooplankton 6.31
pelagic invertebrates 0.03
flatfish 0.27
other fish 0.94
pollock 15.63
benthic invertebrates 52.19
shrimp 12.06
crab 12.31
glopp 0.26
Sum 100
Flathead sole
FLATHEAD SOLE STOMACH DATAhttp://www.dfw.state.or.us/MRP/finfish/sp/flatfish.asp
Stomach Data Discussion
WALLEYE POLLOCK, PACIFIC COD, ARROWTOOTH FLOUNDER, FLATHEAD SOLE
•Which animals have similar diets?•Which prey species occurs in all of the diets?•Which prey species occurs in most of the diets?•Which predator has the most different or specialized diet?
Why do you think a predator has multiple types of prey?
1. What advantages would more prey types in a diet give an animal?
2. Do Pacific cod eat the same prey in all 3 places?3. Do cod eat the most of the same prey in all 3 places?
Make your own food web
http://access.afsc.noaa.gov/REEM/WebDietData/DietTableIntro.php
http://www.sciencedirect.com/science/article/pii/S096706450700197X
Bering Sea Ecosystem
U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 18