How does the size of consumed Blue Cod generally compare to the Red Cod typically eaten by penguins?
Answer
Blue cod are significantly larger (160–220 mm) than the small Red Cod stages (50–80 mm).
A critical factor in the dietary shift is the size disparity between the replacement prey and the historical staple. The Blue Cod that penguins are currently consuming generally measure between 160 to 220 mm. In contrast, the Red Cod that were historically dominant were typically caught when they were in their larval or early juvenile stages, measuring much smaller, around 50 to 80 mm. This difference in size presents a physical challenge, as the larger Blue Cod may be too difficult for parent birds to provision effectively to their growing chicks, potentially resulting in reduced ingestion and lower survival rates for the young birds.
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