Krill in the Antarctic Peninsula

The Antarctic Peninsula sits on the northwest corner of Antarctica, separated from Argentina and Chile by the Drake Passage. The Peninsula is home to a variety of sea creatures that live in this area year-round or migrate to the peninsula over different seasons. There have been studies conducted on certain species, such as Adelie and Chinstrap penguin distribution and abundance, that live on the Antarctic peninsula (Michael Wethington 2023). However, the highest concentration of krill is also located in the waters surrounding this area. It's interesting to consider the distribution and movement of krill within the peninsula as this is a species central to the regulation and biodiversity of the Antarctic food chain.

In addition to environmental changes in the peninsula, such as sea-ice retreat, there are anthropogenic changes over-time potentially impacting the region. Given its proximity to South America, the Antarctic Peninsula is the region that receives the highest level of visitors across the continent (Nicole A. Bender 2016). Tourism has expanded within the peninsula to include activities such as camping, kayaking, cycling, polar plunge, use of remote underwater vehicles, scuba diving, and many others. There are also several protected areas scattered around the peninsula, including:

• Antarctic Specially Protected Areas: "to protect outstanding environmental, scientific, historic, aesthetic or wilderness values, any combination of those values, or ongoing or planned scientific research" (Secretariat of the Antarctic Treaty 2024).
• Antarctic Specially Managed Areas: "to assist in the planning and co-ordination of activities, avoid possible conflicts, improve co-operation between Parties or minimize environmental impacts" (Secretariat of the Antarctic Treaty 2024).

The following maps will be explored through focusing on krill abundance and levels of tourism within the Antarctic Peninsula. This is an exploratory analysis to better visualize if there are areas to focus on with both high abundance of krill and high levels of tourism that could be introduced as specially protected areas. The guiding spatial questions are:

• What is the distribution of krill across the Antarctic Peninsula from 1926-2016?
• Which areas of the Antarctic Peninsula are most vulnerable to tourism, and does this overlap with areas of high abundance of krill?

The Southern Ocean is home to a vast quantity of marine mammals and organisms. This includes multiple types of whales, seals, penguins, albatross, icefish, toothfish, and krill. All of these intertwine to create a balanced Antarctic ecosystem, in which krill play an important role as a cornerstone species. The question of their spatial distribution can be beneficial in order to gain a visual understanding of the change in location or abundance of krill over time. In order to analyze this, I've included data collected by the British Antarctic Survey covering krill samples from 1926 to 2016.

The first map highlighted below includes hotspots of krill abundance surrounding the Antarctic Peninsula from 1926-1996. This shows a central location of krill near the northernmost tip of the peninsula, with fewer samples of krill located in the central and southern sections.

Comparatively, the second map includes data on krill distribution from 1997-2016. This map shows a downward expansion of krill from the northern section of the peninsula towards the Palmer Archipelago. These maps were designed through conducting an analysis on krill distribution quantities from 1926-1996 using the kernel density tool in ArcGIS which works by calculating densities of certain features within a specified area. The same process was used to calculate the density for krill within the peninsula from 1997-2016. This helps provide an overview and general idea of the movement of krill throughout a 90 year time period. It is important to note a caveat that sampling techniques may have evolved over-time, and there is always the likelihood of multiple factors influencing krill movement.

The second part of this spatial analysis focuses on Antarctic tourism. Tourism in the polar regions has increasingly become more accessible, and with it there have been guidelines introduced by the Secretariat of the Antarctic Treaty and the International Association of Antarctica Tour Operators to regulate human activity and interactions with the environment. The goal in visualizing the levels of tourism within the Antarctic Peninsula is to assess whether there are overlaps with known areas of high krill abundance, and where tourism connects with existing protected areas.

Data used to assess the levels of tourism was collected by the Secretariat of the Antarctic Treaty. This includes data on the number of visitors and vessels from 2019-2023, as reported by member states. Based on the chart below, it can be noted that the Antarctic Peninsula receives the highest number of visitors compared to the Ross Sea region, the South Orkney Islands, and Adelaide Island. The second highest visited area, the South Shetland Islands, are located approximately 150 kilometers above the peninsula (Britannica 2024). According to this data, the most visited parts of the peninsula from 2019-2023 were the northwest (199), east (56), and southwest (35).

Below is a map combining tourism hotspots within the peninsula for 2019, 2020, 2021, and 2022. While there is a continuous trend in the north of the peninsula, it can be seen how tourism expands towards the Palmer Archipelago and southern areas of the peninsula throughout the years. Palmer Archipelago has also seen an increase in the abundance of krill as previously shown through the kernel density maps. There are 52 islands within the archipelago, with 4 designated as Antarctic Specially Protected Areas and 1 designated as an Antarctic Specially Managed Area (Secretariat of the Antarctic Treaty 2024).

The next step involves combining data from the krill distribution analysis with data from the number of visitors to the peninsula. The goal of this step is to view areas which may be more vulnerable to human activity. The map to the left was created by using a reclassify tool to create scales to compare details from both datasets, followed by a raster calculator to highlight, in dark red, areas of vulnerability.

As expected, it shows a combined vulnerability towards the central and southern area of the peninsula. The white dots within the map show the location of specially protected areas. The majority of these ASPA zones are within the highest areas of vulnerability, although there is the potential for additional research into the Palmer Archipelago, if there's the possibility for continued southern expansion of krill movement and tourism access. A challenge to consider is the limitation in collected krill data up to 2016, given that tourism data is highlighted for 2019-2023. Future research could center on gathering additional krill distribution data to analyze more recent trends.

Data released by the Secretariat of the Antarctic Treaty notes that there are 24 sites with guidelines on the peninsula, as compared to 266 without guidelines. The map to the left shows the frequency of most visited areas with guidelines highlights in red, overlayed with krill abundance from 1997-2016. Below, areas without specific visitor guidelines for the same timeframe are highlighted in purple.

This leads to the question of whether additional guidelines should be introduced for sites frequently visited by tourists at the southern end of the peninsula, particularly near the Palmer Archipelago, as krill continues to be studied near the southern edge of the peninsula. Protected areas or sites with guidelines can be beneficial to gauge human activity, assess impacts, and curb the introduction of invasive species or harmful activities.

When deciding on which areas to designate as ASPA or where to introduce and enforce guidelines, it can be helpful to consider the role of krill abundance as a factor given that it is an important species to conserve throughout the Antarctic. Following this analysis, areas within the southern section of the peninsula, such as Palmer Archipelago, deserve additional attention as they include high levels of visitors and krill.