Field Assistant Vacancies 2025-26 for MIMMP - NOW CLOSED for Applications

Three field assistant positions (2 x "Sealers" and 1 x "Whaler") are once again available at Marion Island, April 2025 - May 2026. All three positions will henceforth be managed through the South African Polar Research Infrastructure (SAPRI) hosted within the South African Environmental Observation Network (SAEON). Deadline - 07 October 2024.

Full details and applications in the link below:

APPLICATIONS MUST BE SUBMITTED VIA SAEON (click here to redirect for details).

DEADLINE: 07 October 2024

An overview documentary of what you might expect in these positions can be viewed here and further insight about our science can be gained by listening to a public talk (here) or viewing our publications.

Additional information about the positions and a background to the programme can be found on our programme history, 'working with us' and FAQ pages.

If you want a good idea of what life as a sealer is all about on Marion, consider purchasing a copy of our book - 'Pain forms the Character' 

Want to help us continue this globally unique research? Support the programme.

OBITUARY: HARRY ROY BURTON (1940-2024) - MIMMP Collaborator

With sadness we announce the death of a colleague who played an eminently supporting role in the development of the MIMMP, especially in the early days. Harry Roy Burton (borne 06 August 1940 in Victoria, Australia) passed away on Saturday 21 September 2024 in Hobart, Tasmania, after a series of illnesses. Harry spent approximately three and a half years in Antarctica, comprising two winters (1974 and 1978) and five summers at Davis station, conducting research on Antarctic biology and geochemical limnology. He also spent three months as leader of a summer party on Heard Island in 1985, and nine months (August 1993 to May 1994) during the first branding season of southern elephant seal (SES) weaners at Macquarie Island. His major projects included the limnology of the lakes of the Vestfold Hills and the population ecology/biology of the SES on Macquarie Island and elsewhere. Burton Lake in the Vestfold Hills, Antarctica is named after him, and he was awarded the Australian Antarctic Medal in 1987. Naturally, as within the MIMMP, a lot of his work was conducted from remote field camps in difficult conditions.

The 1993 Macquarie Island sealers (left – right: Paul (Tussock) Davis, Harry Burton, John (Snake) van den Hoff and Clive McMahon

In the past, both Frans Jonker (Sealer #39 in the MIMMP chronological hierarchy) of M51 (1994/95) and Clive McMahon (Cat Hunter #45) of M45 (1988/89) enjoyed Harry’s hospitality who created opportunity for them to work with SES in Australia at Macquarie Island, after they had travelled beyond South African shores for adventure. Frans subsequently moved to New Zealand, but Clive stayed on to, in his own words, ‘live, work, learn, and laugh together with Harry while catching and weighing elephant seals, writing papers and breaking new ground’. Clive acknowledged that he was indeed extremely privileged and honoured to have had such a wise and knowledgeable mentor and close friend right to the very end.

Marthan joined Harry on a 1985 scientific expedition to Heard Island

In fact, all of us who rubbed shoulders with Harry were much better off for doing so. I joined Harry on the 1985 expedition to Heard Island, a dream come true. But more than that, Harry supported the SES censusing, marking and resighting programme on Marion Island from its re-launch in 1983. He voiced this support at the SCAR (Scientific Committee on Antarctic Research) seal specialist group meetings and conferences which helped us secure funding within SANAP for this long-term project. He was instrumental in arranging a Southern Ocean wide census of SES and encouraged the weighing of SES weaners! His love for weighing SES pups was rewarded with the scientific papers emanating from this predilection (e.g., Burton et al. 1997; McMahon et al. 2000) being cited extensively in the marine mammal scientific literature. While at the Australian Antarctic Division he also invested his time (he spent six months in 1992 on a sabbatical with me at the MRI), funding (ARGOS satellite tracking costs) and data loggers (satellite transmitters and geolocators) in the MIMMP.   

Harry will be sorely missed. Our sincere condolences go to his family and friends. May he rest in peace.

Compiled by: Marthan N. Bester

Burton HR, Arnbom T, Boyd IL, Bester M, Vergani D, Wilkinson I (1997) Significant differences in weaning mass of southern elephant seals from five sub‑Antarctic islands in relation to population declines. In: Antarctic Communities: Species, Structure and Survival. Pp 335‑338. Battaglia, B., Valencia, J. & Walton, D.W.H. (eds), Springer, Berlin.

McMahon CR, Burton HR, Bester MN (2000) Weaning mass and the future survival of juvenile southern elephant seals, Mirounga leonina, at Macquarie Island. Antarctic Science 12:149-153.       

Marion elephant seal immigration: a benchmark for Integrated Population Models (IPM's)

Modelling immigration in population dynamics studies can be fraught with analytical complexity and uncertainty. Yet, the role of immigration is vital to understand if we are to gain a holistic picture of what makes populations ‘tick’.

The MIMMP’s flagship 4-decade-long uninterrupted mark-recapture experiment on southern elephant seals provided the model for a recent study to improve insight into the role of immigration in population dynamics. The study by a MIMMP team led by Dr Murray Christian (MIMMP postdoc) was published in the Journal of Animal Ecology earlier this year.

Southern elephant seal bull during a breeding season at marion island. photo: nico de Bruyn

A “Research Highlights” paper entitled “Redefining ‘state-of-the-art’ for integrated population models with immigration” has now been published by Chloé Nater from the Norwegian Institute for Nature Research (NINA) praising this work by Murray Christian and colleagues as a ‘benchmark example’!

Christian et al. (2024) is a benchmark example of ‘best practices’ for IPM analyses and a demonstration of how modern science produces not just papers as outputs, but reproducible coding workflows that have the potential to greatly accelerate the pace at which we make scientific progress (Lewis et al., 2018) and create the kind of knowledge needed to respond to the challenges of our rapidly changing world.

(Quoted verbatim from Nater 2024 Journal of Animal Ecology)

“‘best practices’ for future applications of state-of-the-art IPM-tLTRE analyses” Nater 2024 J. Anim. Ecol.

Read the linked papers for a detailed insight into this fascinating aspect of Population Dynamics.

Expedition news: MIMMP tag seals on pristine Prince Edward Island!

In November 2023, 13 scientists landed on sub-Antarctic Prince Edward Island, becoming the first visitors to this pristine island in 12 years. Prince Edward lies approximately 20km from its more well-known neighbour, Marion Island. Although smaller, Prince Edward is more pristine than Marion, largely due to its strict management plan which only enables a small group of visitors for short visits (max of 8 days) every five years.

The rugged coastline of Prince Edward Island. Photo: Rowan Jordaan

Camp near Cave Bay. Photo: Rowan Jordaan

Part of this team, were 2x MIMMP sealers and research associates, Dr Chris Oosthuizen and Dr Rowan Jordaan. Their goal for the expedition was to tag all the recently weaned southern elephant seal pups. This expedition conveniently took place shortly after the conclusion of the annual elephant seal breeding season, the timing was therefore perfect for this activity. The only previous occasion where elephant seal pups were tagged on Prince Edward was in 2004 but because that expedition took part in December, many pups had already departed the island on that occasion and the extent of the breeding population on Prince Edward could not be robustly determined.

Chris (left) and Rowan (right) standing above McNish Bay with Marion Island in the distance. Photo: Chris Oosthuizen

Recently tagged elephant seal pups with their Prince Edward PEBZ tags. Photo: Rowan Jordaan

Not quite knowing what to expect, Chris and Rowan set off with a full set of tags (specially made for Prince Edward Island) and applicators in hand. The rugged coastline was generally not well suited to elephant seals but where there was a favourable beach, elephant seal weaners were in abundance! Chris and Rowan spent the days walking along the coastline until they came across these beaches and then they spent a lot of time finding and tagging all the pups in attendance. Tagging was often interrupted by killer whales who also spent time at the beaches, hoping to catch an unsuspecting weaner in the shallows. The beach with the largest number of weaners, Boggel beach, was situated at the base of a scoria cone and its long, black sandy beach was peppered with elephant seal weaners and a couple of very calm adult males. At the end of several days of tagging, 131 weaners were tagged on this beach alone! What a site this beach would be in peak breeding season!

A group of weaners on Boggel Beach, a volcanic sand beach at the base of a scoria cone. Photo: Rowan Jordaan

The everpresent killer whales patrolling the shallows at busy beaches. Photo: Rowan Jordaan

McNish Bay on the south western corner of Prince Edward was arguably one of the more scenic beaches on the island (and possibly in the archipelago). Surrounded by colossal cliffs, coloured in various shades of reds and browns, this beach faced Marion Island, which could be seen in the distance. It was a warm summers day and after tagging 34 pups on McNish Bay beach, Chris and Rowan had to seek shade in an old sealer shelter where they enjoyed lunch before the long walk back to camp. The weather that day was particularly pleasant and the weather in general always seemed better during the day than at night. This made the days spent walking and tagging more enjoyable compared to the sleepless nights endured in the tents back at camp. We now understand why visitors can only spend a max of 8 days on the island, there aren’t many tents that could survive the wind for much longer!

Chris checks an adult male elephant seal for tags at Cave Bay beach. Photo: Rowan Jordaan

The expedition lasted 7 nights before the team was pulled off the island due to (more) severe weather en route. In total, 412 elephant seal weaners were present on Prince Edward, the majority of which were tagged. This tagging event provides us with valuable information on the size of the elephant seal breeding population on Prince Edward and movement to and from our main study site, Marion Island. All killer whales seen during this expedition have also been seen at Marion. In addition to the weaners, some resting bulls and a few late breeding females, a few non-breeding yearling and sub adults were also noted on the beaches and it was refreshing to see some of these animals carrying tags that they received on Marion Island. We look forward to seeing how many of these seals carrying PEBZ tags are seen on Marion as part of our continuous monitoring taking place there!

Field Assistant Vacancies 2024-25 for MIMMP - CLOSED

Three field assistant positions (2 x "Sealers" and 1 x "Whaler") are once again available at Marion Island, April 2024 - May 2025. All three positions will henceforth be managed through the South African Polar Research Infrastructure (SAPRI) hosted within the South African Environmental Observation Network (SAEON). Deadline - 07 December 2023.

Full details and applications in the link below:

APPLICATIONS MUST BE SUBMITTED VIA SAEON (click here to redirect for details).

DEADLINE: 07 December 2023

An overview documentary of what you might expect in these positions can be viewed here and further insight about our science gained by listening to a public talk (here) or viewing our publications.

Additional information about the positions and a background to the programme can be found on our programme history, 'working with us' and FAQ pages.

If you want a good idea of what life as a sealer is all about on Marion, consider purchasing a copy of our book - 'Pain forms the Character' 

Want to help us continue this globally unique research? Support the programme.

OBITUARY: Prof Rudi van Aarde (Marion Island ‘sealer’; 1974/75/76)

A Marion Island sealer stalwart, Rudi van Aarde, sadly passed away on Friday 21 July 2023. As Sealer #5 in the MIMMP chronological hierarchy, Rudi spent 18 months on Marion Island from 1974/75 to 1975/76 (M31 & M32 teams) studying southern elephant seals (SES) together with Patrick Condy (Sealer #2) although his primary involvement was to study the population ecology of the introduced, feral domestic cat at the island.

Rudi van Aarde (bottom right) as part of the M31 overwintering team at Marion Island. Photo credit: ALSA

Rudi van Aarde (right) during the cat eradication era at Marion island

Upon completion of his MSc dissertation on the cats, he headed off to the French Kerguelen Islands for a few months in the spring/summer of 1977/78 to service a collaborative study on SES between the MRI and Terres Australes et Antarctiques Francaises (TAAF) with the endorsement of the South African Scientific Committee for Antarctic Research (SASCAR). Here he applied his Marion Island experience of SES research on the large SES population of the Courbet Peninsula, Iles Kerguelen. After he was appointed to the lecturing staff of the Department of Zoology at UP (in 1986), he furthered his involvement in SANAP as a principal investigator for studies on the SES from 1986 to 2000 with Ian Wilkinson (Sealer #27) as his PhD student. He was also involved with research on the introduced house mice population of Marion Island. Centrally involved with the planning and execution of the feral house cat extermination programme which lasted from 1977-1993, he personally supervised the release of the first control measure, the morbillivirus feline panleucopaenia, on Marion Island in March 1977 from aboard the SAS Protea.

Over thirty years of conservation ecology research (primarily ecological restoration and African elephant research) followed. Our sincere condolences go to his family and friends. May he rest in peace.

Marthán N. Bester, 26/07/2023

NEW PAPER! Killer whales at Marion Island are more social when there is more food

Since 2006, the Marion Island Marine Mammal Programme (MIMMP) has continuously monitored the killer whale population at Marion Island. Through photo analysis, we have identified 69 individuals at Marion Island, 21 of which were calves born during this period. Various aspects of killer whale ecology, diet, movement social structure and demography have been studied providing insight into how this population compares to other global populations.

A pod of killer whales patrol the Marion Island coastline in search of prey. Photo: Rowan Jordaan

In a new study led by MIMMP Research Assistant and past PhD student, Rowan Jordaan, recently published in Ecology and Evolution, nearly 90 000 photographs taken over 4 739 sightings during 12 years were analysed and used to assess whether the survival of killer whales at Subantarctic Marion Island was influenced by social structure and prey. Prey included species eaten whilst at Marion Island (i.e. Southern elephant seals, king penguins etc.) as well as prey eaten when these killer whales are not at the island (i.e. Patagonian toothfish). We also tested if these same prey species influenced killer whale social structure and reproduction (number of calves) during this same time.

A young killer whale, 4-year-old M062 plays in the swell at Watertunnel Beach. Photo: Rowan Jordaan

Results show that the more social killer whales are, the higher their chance of survival and the greater Patagonian toothfish fishing effort, the greater the survival of Marion killer whales. Furthermore, Marion Island prey was shown to influence the social structure of these killer whales as they were more social when there were more southern elephant seals present at the island. Lastly, none of the prey species included in analyses showed any relationship to the number of killer whale calves born and no environmental variables had any impact on survival or social structure.

Adult male killer whale (M001) sneaks close to a beach hoping catch an unsuspecting king penguins or elephant seal. Photo: Rowan Jordaan

These results suggest that fishery-linked resource availability may be an important influencer of Marion Island killer whale survival. Results suggest that killer whales are able to adjust their social structure in response to changing prey which leads to an increased chance of survival. Lastly, reproduction is not linked to variation in prey numbers suggesting that there are more factors at play in determining when calves are born into this population of killer whales.

The full paper can be read here: https://onlinelibrary.wiley.com/doi/10.1002/ece3.10144

New paper! Density-related reproductive costs and natal conditions predict elephant seal male life history

Adult male southern elephant seal fresh from a battle with another male at marion island. Photo: Kyle Lloyd

Being a male elephant seal is not easy. Few survive to adulthood and even fewer rise above the rest to become the alpha male of their beach. In a recent paper published in Animal Behaviour, MIMMP associate and former PhD student, Kyle Lloyd and colleagues, show that competition starts from birth when males grow and develop the traits needed in later life to establish and maintain mating rights and service groups (harems) of females. Costs of reproduction at adulthood may also be increased for alpha males that need to mate larger harems of females than alpha males of smaller female harems. Thus, decisions about allocating body resources to life history traits such as survival, breeding success and recruitment to the breeding population may differ for individuals that experience different densities of competing males and/or female group size, from birth through to adulthood.

Adult male southern elephant seal defending his small harem at a marion island beach. Photo: nico de bruyn

Using a long-term data set collected at Marion Island, we found that alpha males that dominated larger female harems experienced lower survival rates in later years, likely because there was a greater cost associated with mating more females and protecting their females from more male competitors. Interestingly, when looking back at population metric at birth, we found that males born in years with fewer pups (at the population level) had a higher breeding success and recruited at a younger age than males born in years with more pups. This suggests that males experienced competition for resources during early life and that this competition was reduced when there were fewer individuals to compete against. These findings are interesting because they show how the density of both males and females can have long-term consequences throughout a male’s life. You can read more about our study in Animal Behaviour.

Field Assistant Vacancies for Marion Island 2023-24 - CLOSED

Three field assistant positions (2 x "Sealers" and 1 x "Whaler") are once again available at Marion Island, April 2023 - May 2024. All three positions are embedded within the research programme: "Marion Island Marine Mammals in Changing Environments: Individual Heterogeneity and Population Processes", maintained through the University of Pretoria.

For instructions please read the advertisements carefully here:

Mammalogist- Seals / Killer whales

Application link  below:

APPLICATIONS MUST BE SUBMITTED VIA OUR ONLINE SYSTEM*(click on text to redirect).

DEADLINE: 7 November 2022

*Emailed submissions will not be accepted.

An overview documentary of what you might expect in these positions can be viewed here and further insight about our science gained by listening to a public talk (here) or viewing our publications.

Additional information about the positions and a background to the  programme can be found on our programme history, 'working with us' and FAQ pages.

If you want a good idea of what life as a sealer is all about on Marion, consider purchasing a copy of our book - 'Pain forms the Character' 

Want to help us continue this globally unique research? Support the programme.

Field Assistant Vacancies for Marion Island 2022-23 - CLOSED

Three field assistant positions (2 x "Sealers" and 1 x "Whaler") are once again available at Marion Island, April 2022 - May 2023. All three positions are embedded within the research programme: "Marion Island Marine Mammals in Changing Environments: Individual Heterogeneity and Population Processes", maintained through the University of Pretoria.

For instructions please read the advertisements carefully here:

Mammalogist- Seals / Killer whales

Application link  below:

APPLICATIONS MUST BE SUBMITTED VIA OUR ONLINE SYSTEM*(click on text to redirect).

DEADLINE: 15 October 2021

*Emailed submissions will not be accepted.

An overview documentary of what you might expect in these positions can be viewed here and further insight about our science gained by listening to a public talk (here) or viewing our publications.

Additional information about the positions and a background to the  programme can be found on our programme history, 'working with us' and FAQ pages.

If you want a good idea of what life as a sealer is all about on Marion, consider purchasing a copy of our book - 'Pain forms the Character' 

Want to help us continue this globally unique research? Support the programme.

Can we use molted hair stable isotope and amino acid δ15N values to assess foraging specialization?

Naturally shed tissues, such as hair or feathers, can be sampled using minimally invasive approaches and are increasingly used for stable isotope-based dietary studies. Between November and February each year, southern elephant seals (SES) haul out ashore to undergo a ‘catastrophic’ moult. Their hair and layers of skin are shed while fasting and are replaced by a new pelage before returning to sea. In this latest MIMMP paper led by Dr. Nico Lübcker and colleagues, bulk tissue and amino acid carbon (δ13C) and nitrogen (δ15N) stable isotope values of hair, epidermis, and whiskers of SES were used to evaluate if hair and epidermal isotope values provide dietary information that is ecologically meaningful. Because the shed hair is potentially synthesized while these animals are fasting, it is possible that the stable isotope values measured in the hair do not provide an accurate reflection of the isotope values of their prey.

In the paper “Validating the use of bulk tissue stable isotope and amino acid δ15N values measured in molted hair and epidermis of elephant seals to assess temporal foraging niche specialization” published in Marine Ecology Progress Series, it is demonstrated that the new SES hair is rapidly synthesized from recycled endogenous sources while fasting. Both the bulk tissue and amino acid δ15N values are adversely influenced by the physiological changes associated with fasting. This was similarly observed in the portion of their whiskers synthesized while on land which has been previously published (Lübcker et al. 2020; https://doi.org/10.1007/s00442-020-04645-5).

This study is the first to combine bulk tissue and amino acid isotope values to describe how naturally shed tissues that are synthesized while animals are fasting, and affected by physiological factors. Such physiological method validations are required to understand the limitations of these sampling approaches, and emphasizes the need to differentiate between ecological and physiological factors that influence tissue isotope values before drawing inferences about their foraging and movement ecology. 

Figure from Lubcker et al. 2021. Nitrogen (δ15N) isotope values measured in temporally overlapping, paired hair (circles) and chronologically sub-sampled whiskers (lines) of young-of-the-year (YoY; n = 16 individuals) and adult female (AF; n = 4) southern elephant seals. The mean (±SD) epidermis δ15N values of n = 5 different adult females are also shown for comparison. Solid lines: fitted Loess smoothers with associated standard error (gray shading); vertical gray rectangle: portion of the whisker grown concurrently with hair synthesis during the molt fast; purple dashed lines: position along the whiskers that reflects at sea foraging with the plot position (x-axis) set to zero, signifying the end of the molt fast (Lübcker et al. 2020a). The hair and epidermis bulk tissue isotope values were overlaid with the whisker δ15N values to illustrate the position along the length of the whiskers where the δ15N values were most comparable. The hair and epidermis δ15N values resembled the whisker δ15N values during a known catabolic state.

This finding is topical and challenges the notion that naturally shed hair and epidermal isotope values are useful for dietary reconstructions. Molt in SES is energetically demanding. Stored proteins are catabolized for hair synthesis, leading to additional enrichment of the δ15N values incorporated into the newly synthesized hair. Although naturally shed tissues are easy to collect, the timing of tissue synthesis relative to the life history of the organism should be considered when interpreting stable isotope data. Despite these limitations, molted hair can be used to detect extreme foraging events, which we show using an extensive data set of hair sampled from marked individuals (n = 331) that hauled out on Marion Island during the 2012−2013 annual pelage molt.

Read the full article HERE

OBITUARY: Prof Gideon Rossouw (Gough Island 'sealer' 1975/76)

Gideon Rossouw, 2020. Photo: MN Bester

We regret to inform that, sadly, another stalwart ‘sealer’ has recently passed away. Gideon Rossouw (Gough 21; 1975/76), together with Marthán Bester, investigated the population ecology of the large Subantarctic fur seal population at Gough Island, as well as the resident small breeding colony of southern elephant seals. While training as a zoologist at the University of Stellenbosch, he was recruited to spend the summer at Gough Island as one of two seal researchers. He later went on to research elasmobranch fishes at the then University of Port Elizabeth (Nelson Mandela University), also making a name for himself as a very accomplished palaeontologist, especially on Karoo vertebrates (such as mammal-like reptiles). He lectured widely on this topic and the comparative anatomy of vertebrates. He often toured fossil sites and established fossil collections, together with his students, all over the Karoo. In 1980, he briefly returned to Gough Island for the takeover to augment the seal research of 1975/76. Gideon retired from NMU as Head: Department of Zoology in 2015, eventually moving to Dana Bay, where he passed away on 4 June 2021 at the age of 70. Preceded in death by his wife Engela, he is survived by his son, Jan-Hendrik, daughter-in-law and two grandchildren.

Gideon (left) and Marthán on Gough Island during 1975/76

Marthán N. Bester, 24/05/2021

Happy birthday elephant seals! 15 October - median pupping date

The southern elephant seal annual breeding season peaks today, 15 October. This is the day in the year when most pups are born at Marion Island, and therefore we celebrate the island populations’ birthday today.

One of many southern elephant seal harems at peak breeding season on Marion Island. Photo: Frikkie van der Vyver

A southern elephant seal guards his beach filled with females and pups during the 2020 breeding season. Photo: Frikkie van der Vyver

However, this year is an extra special elephant seal birthday to us seal biologists (aka “Sealers”), because not too long ago we anticipated that for the first time in four decades we would not have a presence on Marion Island in this breeding season!

Thankfully our efforts were rescued and Frikkie and Yinhla are on the island to conduct the total island count today, but even more importantly, to continue with our globally valued 39-year old ‘mark-resight’ research on this species.

Cheers to the ellies and our continued efforts to understand and conserve them and their beautiful habitats!

NEW paper: How did extreme historical harvesting affect fur seal genetics?

Antarctic fur seal bull on Subantarctic Marion Island. Photo: Nico de Bruyn

The MIMMP’s Nico de Bruyn and Marthán Bester contributed to a new paper published in Scientific Reports and lead by collaborators Anneke Paijmans and Joseph Hoffman, assessing the genetic legacy of extreme exploitation in a polar vertebrate.

Global population structure of the Antarctic fur seal inferred by STRUCTURE analysis of 2,000 individuals from eight populations genotyped at 39 microsatellite loci.

Understanding the effects of human exploitation on the genetic composition of wild populations is important for predicting species persistence and adaptive potential.  We therefore investigated the genetic consequences of one of the most extreme episodes of commercial exploitation in history.  Antarctic fur seals were hunted virtually to extinction across their circumpolar distribution.  However, a large genetic dataset uncovered evidence for four relict populations, indicating that the species as a whole was more resilient to hunting than suggested by historical accounts.  Furthermore, despite these populations having experienced demographic declines, sufficient numbers of animals survived to retain comparably high levels of genetic variation. Our results explain the apparent contradiction between the high genetic diversity of this species and its extreme exploitation history.

Read the paper here: https://www.nature.com/articles/s41598-020-61560-8

NATURE paper: Tracking predators to protect Southern Ocean Ecosystems

Southern elephant seal with a satellite tracking device, Marion Island. Photo: Nico de Bruyn

In a rapidly changing world, we need to know which areas of our planet warrant protection from existing, developing and forthcoming threats. This is hard to do objectively in the vast realm of the oceans, and particularly so in the most remote parts, the Southern Ocean. A paper published this week in the journal Nature (together with a companion data paper in the journal Scientific Data) describes a novel solution to this problem, using electronic tracking data from birds and marine mammals.

The solution relies on a simple principle:  animals go to places where they find food. So, identifying areas of the Southern Ocean where predators most commonly go also tells us where their prey can be found. For example, humpback whales and penguins will go to places where they can feed on krill, whereas elephant seals and albatrosses go where they can find fish, squid, or other prey. If all these predators and their diverse prey are found in the same place then this area has both high diversity and abundance of species, indicating that it is of high ecological significance. 

Hindell et al 2020. https://www.nature.com/articles/s41586-020-2126-y

The project was conducted by the Scientific Committee for Antarctic Research (SCAR), with support from the Centre de Synthèse et d'Analyse sur la Biodiversité, France, and the WWF-UK.  

SCAR engaged its extensive network of Antarctic researchers to assemble existing Southern Ocean predator tracking data.  After careful validation, the result was an enormous database of over 4000 individual animal tracks from 17 species, collected by more than 70 scientists (including Nico de Bruyn and Marthan Bester) across 12 national Antarctic programs. MIMMP research associate and past student, Ryan Reisinger, was one of the joint lead authors on this study. This database is now available for public download.

Even this impressive database does not directly represent all Southern Ocean predator activity, because it is impossible to track every species from all their breeding colonies. Simple mapping would therefore provide a biased representation of animal distribution. To overcome this, sophisticated statistical models were used to predict the at-sea movements for all known colonies of each predator species across the entire Southern Ocean. These predictions were combined across the 17 predator species to provide an integrated map of those areas used by many different predators with diverse prey requirements.

The most important of these areas -  areas of ecological significance - are scattered around the Antarctic continental shelf and in two wider oceanic regions, one projecting from the Antarctic Peninsula engulfing the Scotia Arc, and another surrounding the sub-Antarctic islands in the Indian sector of the Southern Ocean.

Marine Protected Areas (MPAs) are a crucial tool in the conservation management toolbox. Existing and proposed MPAs are mostly found within the areas of ecological significance, suggesting that they are currently in the right places. Yet when using climate model projections to account for how areas of important habitat may shift by 2100, the existing MPAs with their fixed boundaries may not remain aligned with future important habitats. Dynamic management of MPAs, updated over time in response to ongoing change, are therefore needed to ensure continued protection of Southern Ocean ecosystems and their resources in the face of growing resource demand by the current and future generations.

Read the article here: https://www.nature.com/articles/s41586-020-2126-y

And the associated Scientific Data paper here: https://www.nature.com/articles/s41597-020-0406-x

MIMMP sealers studying Ross seals in Antarctica

MIMMP associated sealers, Marthan Bester, Horst Bornemann (Alfred Wegener Institute, Germany), Wiam Haddad, Nico Lübcker and Mia Wege deploying satellite-linked telemetry tags on Ross seals (Ommatophoca rossi) as part of the MIMMP affiliated NRF-funded “Ross Seal Foraging Ecology” project during the on-going Southern Ocean Seasonal Experiment (SCALE) spring expedition, onboard the SA Agulhas II at Princess Martha Coast, Antarctica". @SCALEExperiment.

All photo credits: Derek Engelbrecht and/or Horst Bornemann

Field assistant posts for Marion Island 2020-2021 - CLOSED

Three field assistant positions (2 x "Sealers" and 1 x "Whaler") are once again available at Marion Island, April 2020 - May 2021. All three positions are embedded within the research programme: "Marion Island Marine Mammals: Individual Variation and Population Processes in Changing Environments", maintained through the University of Pretoria.

For instructions please read the advertisements carefully here:

Mammalogist- Seals / Killer whales

Application link  below:

APPLICATIONS MUST BE SUBMITTED VIA OUR ONLINE SYSTEM*(click on text to redirect).

DEADLINE: 21 October 2019

*Emailed submissions will not be accepted.

An overview documentary of what you might expect in these positions can be viewed here and further insight about our science gained by listening to a public talk (here) or viewing our publications.

Additional information about the positions and a background to the  programme can be found on our programme history, 'working with us' and FAQ pages.

If you want a good idea of what life as a sealer is all about on Marion, consider purchasing a copy of our book - 'Pain forms the Character' 

Neighbouring seals forage in different places despite similarity of available habitat

Subantarctic fur seal female at sea off Marion Island. Photo: Nico de Bruyn

A new paper published in BMC Ecology by MIMMP collaborator Dr Mia Wege and colleagues shows that there is no difference in predicted potential and available foraging habitat for neighbouring colonies of Marion Island fur seals and yet these animals from different colonies actually do forage in segregated areas at sea.

Figure 1: A theoretical representation of geographical structuring. The black dots represent the colony locations and the coloured blobs the home-ranges of individuals travelling from the respective colonies.

Several species of central-place foragers, such as seabirds, penguins and seals, have colony-specific foraging areas and forage in different areas at sea compared to conspecifics from neighbouring colonies. Individuals from neighbouring colonies even segregate from each other spatially when they are situated well within each other’s foraging range. This is known as habitat structuring and is the concept shown in Figure 1, where the black dots represent the locations of the colonies, and the coloured blobs are the foraging ranges of individuals from the different colonies.

Figure 2: At-sea locations of 121 female Subantarctic and Antarctic fur seals from Marion Island, 2009-2015 during a) summer and b) winter. The different coloured dots represent the three different colonies.

So why would individuals from one colony rather swim or fly further away from their respective colony than forage in the same area as their neighbours? Currently there are several hypotheses for this, ranging from the costs associated of travel, competitive exclusion by neighbours and even different preferences to environmental drivers by neighbouring colonies used to navigate and find prey resources.

Marine predator foraging movements are, among others, driven by bottom-up oceanographic processes such as sea-surface temperature. If this small-scale segregation by neighbouring colonies of marine central-place foragers are indeed driven by differential preferences or exposure to environmental conditions, then we would expect segregated foraging areas to have different habitat characteristics.

Six-years of tracking data (2009-2015) from one Antarctic and two Subantarctic fur seal colonies at Marion Island showed that different colonies situated around the coastline of the island forage in segregated areas at sea, irrespective of species (Figure 2).  Using these two fur seal species as models, we investigated how the habitat characteristics of segregated foraging areas differ between the colonies across seasons. We used remotely sensed environmental variables and tracking data of known foraging locations using machine learning boosted regression trees to model key environmental variables associated with areas of fur seal restricted search behaviour (a proxy for foraging).

We found no differences in the relative influence of key environmental variables to fur seal female foraging habitat between colonies and seasons. Furthermore, the model predicted that the potential foraging areas of females from the three colonies should overlap, and the fact they do not in reality indicates that factors other than environmental are influencing the location of each colony’s foraging area. Small-scale spatial segregation between neighbouring colonies are therefore not dictated by bottom-up processes.

Link to the paper in BMC Ecology by clicking here.

Passing of a previous sealer: Azwinndini Justice Ramunasi

Justice on Marion Island in 2005. Photo: Nico de Bruyn

We regret to share the sad news of the passing of Mr Azwinndini Justice Ramunasi. He was a Marion Island overwintering “SEALER” in 2004/05 as part of the Marion 61st team, and his Sealer number is 51. At the time of his passing he was attached to the Department of Zoology in the School of Mathematical and Natural Sciences, University of Venda, as a lecturer.

Justice graduated from the University of Pretoria, Faculty of Natural and Agricultural Sciences, with an MSc Zoology degree focused on the diet of Marion Island fur seals, in 2010.

Mr Azwinndini Justice Ramunasi passed away on Thursday, 29 August 2019.

On behalf of the MIMMP, we extend our deepest sympathy to the Ramunasi family, relatives and friends.

New paper shows how breeding costs vary between females

A new paper published online early in the journal Population Ecology by MIMMP postdoc Chris Oosthuizen and colleagues shows that breeding for the first time is costly, but only for “low quality” individuals.

Elephant seal females do not feed at all during lactation, and may lose 30 % of their body mass in a breeding season. Energy resources are more limiting for young breeding females because of their smaller body size and lower blubber reserves relative to older females. Young female elephant seals also reproduce before completing body growth, constraining the energy available for somatic maintenance and growth. Young first-time breeders may therefore be expected to have lower survival and subsequent breeding probabilities than those delaying reproduction to an older age.

Alternatively, the individual quality hypothesis predicts that high-quality individuals should reproduce at an early age, survive better, and have a greater probability of breeding in subsequent years. In this case, recruitment age is an indicator of “individual quality” – phenotypic or genetic characteristics that improves fitness.

Southern elephant seal females have varying costs associated with breeding. Photo: Chris Oosthuizen

We used statistical models to partition the life trajectories of female elephant seals into two classes which represent individuals with different breeding and survival probabilities. This analysis enabled us to show that individual differences (“individual quality”) governs the expression of trade-offs with first reproduction in elephant seals, with an immediate survival cost of first reproduction present among “low quality” individuals only. Our finding that individuals that recruit earlier in life survive and reproduce better than delayed breeders supports the hypothesis that recruitment age is an indicator of “individual quality”.

Click here to access the paper!