Macaroni Penguins, and How to help them fight extinction
How Macaroni Penguin population is declining due to climate change, and what could be done to help save them.
Savannah Strome
OSC
Zawadzki
July 13, 2022
Macaroni Penguins, and How to help them fight extinction
Background information
Macaroni Penguins are experiencing a rapid population decline that is linked to global warming through climate change (Mangelsen, n.d.). Macaroni penguins mainly reside in the sub-Antarctic and Antarctic Peninsula, where they prefer to live on rocky, water-bound cliffs (Mangelsen, n.d.). The coastline habitat is an integral part of this penguin’s lifestyle, as having access to the ocean provides food and transportation for migration. The Macaroni penguins are migratory animals, they begin their reproduction cycle in late October by migrating to 216 different colonies (Mangelsen, n.d.), like South Georgia, the Falkland Islands, the South Sandwich Islands, Bouvet Islands, and other islands near the Antarctic peninsula (Mangelsen, n.d.). They average about 50 breeding sites on the islands (Mangelsen, n.d.), creating large colonies to nest. The process of reproduction is timely: two eggs are laid in early November and are incubated for 33 to 37 days (Mangelsen, n.d.). Once their young hatch, the Macaroni penguins guard their offspring for an extensive 25 days (Mangelsen, n.d.) until their migration back to the Antarctic begins in April or May (Mangelsen, n.d.). During this time, the mother of the chick forages for food along the colony's coastline, while the father is protecting his child from other predators located on their island (Mangelsen, n.d.). The young join together for protection from local predators and colder climates while both parents begin hunting for food (Mangelsen, n.d.). After the 11-week period from birth to independence, the juvenile penguins collect food themselves and being their own reproductive cycles (Mangelsen, n.d.). The penguin’s life span ranges from 8 to 15 years (Mangelsen, n.d.), meaning they partake in reproduction migration multiple times within their lifetime with the same breeding partner (Mangelsen, n.d.). A sustainable food source is another key factor in the Macaroni penguin’s livelihood, as an adequate source of food ensures their breeding success, the strength of their young, and with that, the future of their population. Krill, small crustaceans, make up the majority of the penguin’s diet and are plentiful in the Antarctic region (Li, 2021). Macaroni penguins consume 4 million tons of Krill a year (Kavanagh, 2016) with an average total population greater than 6 million (Mangelsen, n.d.). Krill, being a smaller organism, are generally consumed in large amounts to sustain a single penguin. The abundance of Krill is impactful on the Macaroni Penguin’s breeding cycle, as the migration requires more energy as well as feeding the newly born chicks (Li, 2021). Krill tend to exist closer to floating ice sheets and undersea covered ice as they continue the food chain by feeding on algae that primarily live under the ice (Li, 2021). The food chain consists of seals consuming penguins, who consume Krill, and finally Krill that feast on algae (Li, 2021). Disruptions to this particular food chain can indirectly affect the Macaroni Penguin’s population and survival, as the abundance of their prey is dependent on the continuing food chain. The Macaroni penguins, numerically the largest of all penguin species, are at risk due to a lack of abundance in Krill because of global warming (Li, 2021). Food plays a key role in sustaining a population like the Macaroni penguins, and the decrease in a single primary food source can lead to extinction and other indirect negative effects on the rest of the food chain.
Threats
The Macaroni Penguin population is decreasing from 9 million to 6.3 million individuals over the course of 36 years (Mangelsen, n.d.). While the Macaroni Penguin remains the largest population compared to other species of penguins (Li, 2021), their rapidly increasing decline may lead to extinction. They are listed by the International Union for Conservation of Nature as prone to extinction (Cresswell et al., 2008), and without human involvement and support, Macaroni penguins will continue to die off faster than they are reproducing. The prominent issue threatening the penguins is climate change’s effect on the scarcity of their main food source (Cresswell et al., 2008), Krill. While Macaroni penguins are also experiencing new invasive species being introduced and oil spills as pollution (Mangelsen, n.d.), lack of food is the most negatively impactful factor affecting their populations. Krill are being decimated by overexploitation and through the indirect cause of global warming (Kavanagh, 2016). They are subject to overfishing, as Krill are commonly used as aquaculture feed, fishing bait, and animal food (Li, 2021). These small crustaceans residing in the Antarctic ingest microalgae, which are substantially found under sea ice (Li, 2021). As global warming raises the average temperature in the Antarctic, the ice sheets are melting as a response (Li, 2021). The ice sheets, the microalgae’s habitat, are disappearing at an alarming rate for the Krill and other species. Krill are being forced to limit their dispersal and range near the coast, as their abundance of food decreases along with the surface area of the sea ice (Li, 2021). Without a constant food supply, the Krill populations will be unsustainable and thus decrease with their food. Since the 1970s, there has been an 80% loss of Krill in Antarctica (Li, 2021), which coincides with increases in global warming and climate change. Krill populations are likely to move southwards to more habitable conditions where waters are colder with more sea ice coverage (Li, 2021). This range shift in habitat as a response to climate change affects the synchrony created between the penguins and Krill.
The relationship between the population declines of algae and Krill due to climate change indirectly affects the Macaroni Penguin through the food chain. This bottom-up domino effect of disappearing food sources is adding further stress on the penguins and their survival rates. Since Krill are dying out because of their lack of food, the penguins do not have and cannot receive sufficient nutrients for their life and reproductive cycles. Access to large amounts of Krill is required to support an individual and their offspring during the breeding season (Li, 2021). The penguin’s offspring rely on their parents for weeks after their born for food and ocean resources, which are becoming increasingly harder to find (Mangelsen, n.d.). The ice sheets, where Krill occur more populous (Li, 2021), are melting near coastlines and habitats where penguins live and breed (Mangelsen, n.d.). If a penguin cannot support themselves and their child adequately, it is most likely that their child will not survive. The decline in Macaroni Penguins is mainly due to their unsuccessful reproduction and inability to raise a new healthy generation. A study was conducted in South Georgia, an island northward off the Antarctic coast, where scientists observed changes in the Macaroni Penguin’s reproduction (Paye, 2022). South Georgia is one of the most northward islands that the penguins migrate to to breed, and its geographical location has demonstrated the effects of global warming on the food chain. As global warming increases sea temperatures, islands closer to the equator, like South Georgia, experience the costly effects of the ice sheets melting near the coastlines. The ripple effect this has on South Georgia was examined by scientists (Cresswell et al., 2008), which led them to discover mass amounts of unsuccessful breeding due to the lack of abundance of Krill (Cresswell et al., 2008). Although the Macaroni Penguin is considered to have one of the largest populations (Mangelsen, n.d.), no species can survive without fruitful reproduction. An eventual extinction is underway for the Macaroni Penguins as they experience the indirect results of climate change, and human involvement is necessary to ensure their survival.
Methodology
The primary cause behind the Macaroni Penguin population decline has been investigated and discovered to be the paucity of Krill. Few further studies have linked climate change as the indirect cause of this decline, but more research is needed to make a complete conclusion. It is hypothesized that Krill are moving southward (Li, 2021) and becoming asynchronous with the penguins because of climate change, and all that has been concretely discovered is the lack of Krill near the breeding grounds (Li, 2021). Further research is needed to examine how the Krill is specifically affected by the rising sea temperatures and other factors of climate change, as the population as a whole could potentially be experiencing a range shift southwards. If an experiment was conducted that focused on sub-Atlantic Krill behavior in relation to global warming, there would be more knowledge on how to help sustain Krill populations for Macaroni Penguins. In contrast, Krill could be dying more rapidly than they are able to adapt and shift their range in response to rising sea temperatures. If this were the case, further knowledge is required to understand and pinpoint the evidence highlighting the population decline, as scientists only theorized issues within the food chain. Data and evidence will lead to action, as an experiment that follows the number of Krill in response to changing temperatures and external factors like overfishing, could help with indirectly preserving Macaroni Penguins. The main question that needs to be asked and answered is, how can humans help Macaroni Penguins through the research and conservation of Krill? As it has already been concluded that the penguins are at risk of extinction due to a lack of Krill, then researchers need to find a solution to support Krill. The first step in this process would be to observe the range and dispersal of Atlantic Krill and their population numbers. A small crustacean is difficult to monitor, but using the data of where most Macaroni Penguin reproduction is most successful, it can be assumed that a large population of Krill is to be found. Over time, scientists could monitor whether the penguin colony’s reproduction changes and if a change occurs, how did Krill enact that change? If reproduction rates were decreasing on an island that once was a successful breeding location, scientists could move southward and observe if any Krill migrated downwards for cooler temperatures. If an island southward increased in penguin population, then it could be assumed that the Krill’s range shifted to find a colder habitat for better food access. If the southern island showed no significant change in breeding rates, then it could be estimated that Krill populations are not adapting to climate change fast enough and are dying out. If it comes to the conclusion that Krill are not shifting their range and in fact are suffering, then a map could be made of dying Krill populations compared with Krill fishing locations. The purpose of this would be to group Krill decline with overfishing and the ice sheets melting. There are two possible outcomes for both experiments, that Krill are either migrating or dying out altogether, both of which provide helpful information in saving the Macaroni penguins.
Action
If Krill are migrating southwards due to higher temperatures affecting the abundance of their food, the issue changes from helping conserve Krill to conserving synchrony between the penguins and their food source. Human involvement in the form of relocation could be beneficial. Relocating a small group of Macaroni Penguins southward to a more significant food source could create an “artificial range shift”, where the relocated Macaroni Penguins successfully reproduce in new colonies to the point where the population becomes large enough to allow the northern Macaroni Penguins to become non-existent. The goal is for the Macaroni Penguin’s range to be shifted southward, following a similar response to their prey. The problem is found to be the decline of Krill population in response to climate change and overfishing, efforts can be implemented to reduce overexploitation and give Krill a higher chance of survival against global warming. Implementing protected areas designed to limit Krill overfishing could help revive their population numbers. Global warming is a growing problem that is continuing at a rate faster than it is solvable when it comes to preventing the penguin's extinction, thus efforts to reduce environmental stressors like Krill exploitation would slow down the decline and provide more time for the Macaroni Penguins to naturally adapt.
Conclusion
By investigating and conserving the Macaroni Penguin's food source, Krill, the population would be sustainable. Climate change is causing species to react to rising temperatures because of global warming, which has an overspreading effect on the food chain and other organisms involved. The asynchrony caused by global warming is threatening species directly and indirectly, to the point where human involvement is necessary to help return to equilibrium.
Bibliography
Cresswell, K.A., WIedenmann, J., & Mangel, M. (2008). Can macaroni penguins keep up with climate- and fishing-induced changes in Krill? Polar Biology, 31, 641-649. https://link.springer.com/article/10.1007/s00300-007-0401-0
Kavanagh, A. (2016, September 28). Macaroni Penguin Population on the Decline. PEW. https://www.pewtrusts.org/en/research-and-analysis/articles/2016/09/28/macaroni-penguin-population-on-the-decline
Li, F. (2021, January 15). How the Macaroni Penguin’s Population Is Decimated by Overfishing and Climate Change. Climate Conscious. https://medium.com/climate-conscious/how-the-macaroni-penguins-population-is-decimated-by-overfishing-and-climate-change-fb3debe5af35
Mangelsen, T. D. (n.d.). Macaroni penguin - species. Center for Biological Diversity. Retrieved July 13, 2022, from https://www.biologicaldiversity.org/species/birds/penguins/macaroni_penguin.html
Paye, A. (2022). Combatting Climate Issues Facing the Macaroni Penguins. Core Path Ways. http://corepathways.georgetown.edu/portfolio/combatting-climate-issues-facing-the-macaroni-penguins/
