ecosystem importance: Antarctic top predator (Introduction)

by David Turell , Saturday, August 27, 2022, 19:18 (602 days ago) @ David Turell

Leopard seals:

https://www.sciencedaily.com/releases/2022/08/220826165022.htm

"The combination of the extreme climate in Antarctica, the species' solitary habits and their lethal reputation makes leopard seals one of the most difficult top predators to study on Earth. Marine biologists have now gathered baseline data on the ecology and physiology of the leopard seal, the enigmatic apex predator of the Antarctic.

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"Kienle (first author) and the team documented the flexible behaviors and traits that may offer leopard seals the resilience needed to survive the extreme climate and environmental disturbances occurring around Antarctica.

"This study greatly increases our understanding of leopard seals' life history, spatial patterns and diving behavior," Kienle said. "We show that these leopard seals have high variability (or, flexibility) in these different traits. Across the animal kingdom, variability is vital for animals adapting and responding to changes in their environment, so we're excited to see high variability in this Antarctic predator."

"Adult female leopard seals are much larger than adult males; in fact, females are 1.5 times larger and longer.

"The team measured one of the largest leopard seals ever, an adult female they nicknamed "Bigonia," who weighed 540 kg (1,190 lbs.).
Female-biased sexual dimorphism (where females are larger) is unusual among marine mammals, a diverse group that includes polar bears, whales, dolphins, seals and sea lions, but leopard seals are the most extreme example of female-biased dimorphism among the 130+ species of marine mammals.

"Why females are larger than males is not known, although Kienle explained other studies show that larger females are better at defending feeding areas, as well as stealing prey from smaller seals. Larger females also eat bigger, energy-rich prey, including fur seals and penguins, while males and smaller females often eat smaller prey like krill and fish. This suggests that the larger body size in adult females is beneficial and offers a selective advantage that Kienle and team will continue to explore.

"From the movement data, female leopard seals spent more time "hauled out" -- or coming out of the water to rest on ice or land -- than males."

Comment: an isolated ecosystem with its top predators. Recent entries have referred to this as a food web. How does this relate to humans? The fish the seals eat affect the food webs of fish we eat. They are all interconnected.