2020 marks the sixth consecutive year of seabird die-offs in Alaska. Alaska's northern oceans have been experiencing record-breaking, above-average sea surface temperatures. Seabirds eat zooplankton and cold-water fish that are both reliant on cold water. If the cold-water fishes have relocated because the ocean is too warm, or less zooplankton are reproducing in the warmer water, then the seabirds have a more difficult time finding enough food. Coldwater fish are fattier and provide more calories and nutrients for the birds, so even if they can find warm-water fish to eat, they may still have trouble meeting their calorie needs.
The seabirds affected in 2020 are:
Crested Auklets
Horned Puffins
Common Murrs
Short-tailed Shearwaters
Northern Fulmars
Black-legged Kittiwakes
Most of the dead birds appear to have died of starvation. Murres, for example, have a high metabolic rate and consume 10-30% of their total body weight every day. Changes to their food supply can impact their basic functions such as flying, feather molt and weatherproofing, and thermal regulation. Seabird die-offs also impact the entire population because of the reduction in breeding adults and the low productivity rate (success of eggs becoming chicks and becoming adults). Some species have experienced reproductive failure because the females are not in good enough body condition to produce eggs.
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