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Marine Biology

Mass Seabird Die-Off in the Bering Sea: Causes and Concerns

by Peter
written by Peter

Why Are Puffins and Other Seabirds Dying in the Bering Sea?

The Bering Sea is home to a diverse population of seabirds, including puffins, crested auklets, horned puffins, and murres. In 2016, a mass die-off of seabirds occurred in the eastern Bering Sea, with an estimated 3,150 to 8,800 birds perishing.

Cause of the Die-Off

A new study published in PLOS One suggests that climate change is at least partly responsible for the die-off. The study found that warming waters and a reduction of ice in the Bering Sea have led to a decline in cold-water plankton, which are a major food source for seabirds.

Signs and Symptoms of Seabird Starvation

The seabirds that died in the 2016 die-off were severely emaciated, indicating that they had died of starvation. Other signs and symptoms of seabird starvation include:

  • Lethargy
  • Weakness
  • Loss of appetite
  • Weight loss
  • Dull feathers
  • Disorientation

Why Are Tufted Puffins Molting Late?

Tufted puffins typically molt between August and October, once they have already migrated to winter foraging grounds. However, the tufted puffins that died in the 2016 die-off were in mid-molt when they washed ashore in October, suggesting that they had been molting late.

Molting is a stressful period for birds because it increases their energy needs but also reduces their ability to fly and dive, making it difficult to find food. The tufted puffins that died in the 2016 die-off may have been molting late because they were unable to find enough food to sustain themselves during this vulnerable period.

How Does the Availability and Quality of Prey Affect Seabird Survival?

Seabirds rely on a variety of prey species, including fish, plankton, and krill. The availability and quality of these prey species can have a significant impact on seabird survival.

In the Bering Sea, cold-water plankton are a major food source for seabirds. However, warming waters and a reduction of ice have led to a decline in cold-water plankton. This has in turn reduced the availability of prey for seabirds that feed on coldwater fish like pollock and capelin.

In addition, the fish that are available are less calorie-rich because they are eating smaller plankton. This means that seabirds are getting less energy from the food they eat, which can lead to starvation.

What is the Future of Seabirds in the Bering Sea?

The future of seabirds in the Bering Sea is uncertain. Climate change is continuing to warm the waters and reduce the amount of ice in the Bering Sea, which is likely to have a negative impact on seabird populations.

However, seabirds are resilient creatures, and they have adapted to changing conditions in the past. It is possible that seabirds will be able to adapt to the changing conditions in the Bering Sea, but it is also possible that their populations will decline.

Only time will tell what the future holds for seabirds in the Bering Sea.

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Zoology

Wisdom: The Oldest Known Albatross, Nesting at 67 and Inspiring Conservation

by Peter
written by Peter

Wisdom: The Oldest Known Albatross, Still Nesting at 67

Longevity and Resilience

Wisdom, the world’s oldest known wild bird, has once again laid an egg at the remarkable age of 67. This Laysan albatross has been nesting on Midway Atoll in the Papahānaumokuākea Marine National Monument since 2006, raising at least nine chicks with her lifelong mate, Akeakamai. It is estimated that over her lifetime, Wisdom has raised an astonishing 30 to 35 albatross chicks, outliving several of her mates.

Scientific Significance

Wisdom’s longevity and reproductive success have made her an icon in the scientific community. Biologists are fascinated by her ability to survive and reproduce at such an advanced age, challenging previous assumptions about the lifespan of wild birds. Her continued nesting provides valuable insights into the resilience and adaptability of albatross species.

Conservation Icon

Wisdom has also become a symbol of the conservation challenges facing seabirds. Laysan albatrosses are listed as Near Threatened by the IUCN due to threats such as invasive species, fishing nets, oil spills, and plastic pollution. Wisdom’s story highlights the importance of protecting their nesting grounds and mitigating these threats to ensure the survival of her species.

Nesting Habits

Laysan albatrosses are monogamous birds that typically return to the same nesting site each year. They form long-term pair bonds and share responsibilities for incubating their single egg. Unlike some other seabird species that lay multiple eggs, albatrosses invest heavily in raising a single chick, making each egg crucial for the survival of the colony.

Egg Incubation

Wisdom and Akeakamai will share egg-tending duties, switching off every two to three days while the other forages for food. It takes approximately two months for an albatross egg to hatch, so the chick is expected to arrive in mid-February or earlier.

Threats to Albatrosses

Despite their remarkable adaptations, albatrosses face numerous threats throughout their lives. On their nesting grounds, they are vulnerable to invasive mammals like foxes and rats. At sea, they encounter fishing nets, longlines, oil spills, and plastic pollution. Wisdom’s survival and longevity are a testament to her resilience and the importance of conservation efforts to protect her species.

Wisdom’s Journey

Over her lifetime, Wisdom has traveled an estimated two to three million miles, navigating the vast oceans and avoiding countless threats. Her journey serves as a reminder of the interconnectedness of our planet and the challenges faced by migratory species.

Conclusion

Wisdom’s story is an extraordinary tale of longevity, resilience, and conservation. Her continued nesting at the age of 67 is a testament to the adaptability and resilience of these magnificent birds. As a symbol of the challenges facing seabirds, Wisdom’s legacy inspires us to protect their habitats and ensure the survival of her species for generations to come.

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Marine Biology

Bycatch Neutrality: A Comprehensive Guide to Sustainable Fisheries

by Rosa
written by Rosa

Bycatch Neutral: A New Approach to Sustainable Fisheries

Understanding Bycatch

Bycatch refers to the unintended capture of non-target species, such as seabirds and sea turtles, during fishing operations. Overfishing can lead to excessive bycatch, posing a significant threat to marine ecosystems.

The Impacts of Bycatch on Seabirds and Sea Turtles

Seabirds and sea turtles are particularly vulnerable to bycatch. Many seabird species are long-lived and have low reproductive rates, making them slow to recover from population declines. Sea turtles are also long-lived and face numerous threats, including bycatch.

Current Bycatch Mitigation Strategies

Fisheries have traditionally used various methods to reduce bycatch, including:

  • Using safer fishing gear, such as circle hooks and turtle excluder devices
  • Avoiding areas where seabirds and sea turtles are known to congregate
  • Limiting fishing effort during peak bycatch seasons

The Concept of Bycatch Neutrality

Despite these efforts, bycatch remains a problem. The concept of “bycatch neutrality” emerged as a potential solution. This approach aims to offset the impacts of unavoidable bycatch by investing in conservation measures that benefit the affected species.

How Bycatch Neutrality Works

Under a bycatch neutral policy, fisheries that exceed bycatch limits would be required to fund conservation projects that directly benefit the affected species. These projects could include:

  • Removing introduced predators from breeding islands
  • Restoring degraded habitats
  • Conducting research to improve bycatch mitigation techniques

Benefits of Bycatch Neutrality

  • Provides a financial incentive for fisheries to reduce bycatch
  • Directs funding towards conservation measures that benefit affected species
  • Promotes ecosystem-based management by considering the impacts of fishing on non-target species

Challenges of Bycatch Neutrality

  • Determining appropriate conservation measures and funding levels
  • Ensuring that fisheries comply with bycatch limits
  • Allocating responsibility between governments, fisheries, and taxpayers

Alternative Bycatch Mitigation Strategies

In addition to bycatch neutrality, other strategies are being explored to reduce bycatch, such as:

  • Implementing a bycatch tax to fund conservation efforts
  • Imposing conservation fees on individual ships with high bycatch rates
  • Developing new fishing technologies that minimize bycatch

Conclusion

Bycatch neutrality is a promising approach to addressing the impacts of overfishing on seabirds and sea turtles. By investing in conservation measures that benefit affected species, bycatch neutrality aims to promote sustainable fisheries and protect marine ecosystems. However, additional research and stakeholder collaboration are needed to address the challenges associated with implementing bycatch neutral policies.

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Animal Behavior

Albatross Divorce Rates Soar as Climate Change Takes Toll on Nesting Success

by Rosa
written by Rosa

Albatross Divorce Rates Skyrocket Due to Climate Change

Rising Sea Temperatures Impact Nesting Success

Albatrosses, known for their lifelong partnerships, are facing a growing threat: climate change. A recent study has revealed that divorce rates among these seabirds have doubled in recent years, largely due to the impact of rising sea surface temperatures on their food supply.

The Importance of Mate Fidelity

Albatrosses are highly social creatures that form strong bonds with their partners. They typically mate for life, working together to raise their demanding chicks. By staying together, couples build trust, communication, and coordination, which are essential for successful breeding.

The Impact of Food Scarcity

However, climate change is disrupting this delicate balance. Rising sea temperatures are导致nutrient-poor water, which reduces the availability of fish and squid, the albatrosses’ primary food source. This food scarcity is forcing the birds to spend more time and energy searching for nourishment.

Delayed Mating and Breeding Failure

As a result, albatrosses are returning to their nesting sites later in the mating season. This delay can have a significant impact on their breeding success, as chicks that hatch later have a lower survival rate. Additionally, the poor health of the birds due to food scarcity further reduces their chances of successfully raising a chick.

The “Partner-Blaming Hypothesis”

In a surprising twist, the study found that even some couples that successfully raised chicks were still divorcing. Researchers believe that this may be due to elevated stress hormones in the females. These hormones may lead the females to misinterpret the challenges of raising chicks in poor environmental conditions as a lack of effort on the part of their partners. This phenomenon has been termed the “partner-blaming hypothesis.”

Potential Impacts on Albatross Populations

The high divorce rates among albatrosses are a cause for concern, as they could have significant implications for the overall population. If breeding success continues to decline, fewer albatrosses will be produced, potentially leading to population declines in the future.

The Need for Conservation Measures

Conservationists are urging governments and organizations to take action to mitigate the impacts of climate change on albatross populations. This includes reducing greenhouse gas emissions, protecting albatross nesting sites, and implementing sustainable fishing practices.

Conclusion

The rising divorce rates among albatrosses serve as a stark reminder of the far-reaching impacts of climate change on wildlife. By understanding the challenges these birds face, we can develop effective conservation strategies to protect them and ensure their survival in the face of a changing climate.

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Ecology and Evolution

Giant Mice of Gough Island: A Case of Island Evolution and Conservation Crisis

by Rosa
written by Rosa

Giant Mice of Gough Island: A Case of Island Evolution

Nestled in the remote South Atlantic, Gough Island is a haven for seabirds. However, this avian paradise has been invaded by an unlikely predator: giant mice. These mice, descendants of rodents that arrived on the island in the 19th century, have evolved to be twice as large as their mainland counterparts. Their unusual size and predatory behavior are threatening the survival of several seabird species on the island.

Evolutionary Adaptation

Researchers have discovered that the mice on Gough Island have adapted to their unique environment through a process called island gigantism. This phenomenon occurs when small animals introduced to an island without natural predators or competition grow larger over time. On Gough Island, the mice have found an abundant food source in the form of seabird chicks. This steady diet of high-calorie prey has allowed them to maintain their body mass or even gain weight during winter, when food is scarce.

Ecological Impact

The mice’s predation on seabird chicks has had a devastating impact on the island’s avian populations. Two critically endangered species, the Tristan albatross and the Gough bunting, are facing extinction due to the mice’s voracious appetite. The mice are also contributing to declines in other seabird species, threatening the entire island ecosystem.

Conservation Challenges

Researchers are actively studying ways to control the mice population on Gough Island. One potential solution is an aerial drop of poison bait pellets. However, this operation would be complex, costly, and risky. There is no guarantee of success, but researchers believe that it is the only way to save the island’s seabirds from extinction.

The Role of Diet

The mice on Gough Island provide a unique example of how diet can influence evolution. Their unusually large size is a direct result of their adaptation to a diet of seabird chicks. This research highlights the importance of understanding the complex interactions between species and their environment.

Island Ecology

The case of the giant mice on Gough Island is a fascinating example of island ecology. Islands provide unique environments that can lead to the evolution of distinct species and populations. Understanding the ecological processes that occur on islands can help us better manage and conserve these fragile ecosystems.

Invasive Species

The mice on Gough Island are an example of an invasive species, a non-native species that has been introduced to an ecosystem and causes harm to native species. Invasive species can have a significant impact on biodiversity and ecosystem functioning. Preventing the introduction of invasive species and managing existing populations are crucial for the conservation of island ecosystems and the species that depend on them.

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