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11 pages, 623 KiB

Open AccessArticle

The First Report of Mycoplasmas in Antarctic Pinnipeds: The Results of a Survey

by Orestes M. Vega-Orellana, Rubén S. Rosales, José B. Poveda, Francisco J. García-Peña, Daniel García-Párraga, Susana Pedraza-Díaz, Luis M. Ortega-Mora, Joachim Spergser and Ana S. Ramírez

Animals 2025, 15(7), 937; https://doi.org/10.3390/ani15070937 - 25 Mar 2025

Cited by 1 | Viewed by 491

Abstract

The aim of this study was to investigate the presence of Mycoplasma spp. and their identification in seals from Antarctica. During January and February 2010, 59 Antarctic fur seals (Arctocephalus gazella), 17 Weddell seals (Leptonychotes weddellii), and 5 Southern elephant seals (Mirounga leonina) were captured in three Antarctic islands. Oral and genital samples were collected, cultured, and cloned. The Intergenic Spacer Region 16S-23S rDNA (ISR) PCR products were sent for sequencing. Seventy-four (91.4%) out of the eighty-one seals sampled were PCR positive. From those, 57 isolates were cultured. Mycoplasmas were more prevalent in the mouth in comparison to the reproductive tract. The percentage of isolates were 76.3%, 58.8%, and 40.0% for Antarctic fur seals, Weddell seals, and Southern elephant seals, respectively. The ISR sequences divided the isolates into six clusters. Four clusters presented a very high similarity percentage with mycoplasma sequences obtained from seals. However, none of these mycoplasmas have been described to date. Cluster 1 is also close to M. miroungigenitalium. This study represents the first report of Mycoplasma species adapted to Antarctic pinnipeds. The findings contribute to the understanding of the ecology of mycoplasmas in Antarctic pinnipeds. Full article

(This article belongs to the Section Mammals)

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11 pages, 1416 KiB

Open AccessEditor’s ChoiceCommunication

Evaluating Thermal and Color Sensors for Automating Detection of Penguins and Pinnipeds in Images Collected with an Unoccupied Aerial System

by Jefferson T. Hinke, Louise M. Giuseffi, Victoria R. Hermanson, Samuel M. Woodman and Douglas J. Krause

Drones 2022, 6(9), 255; https://doi.org/10.3390/drones6090255 - 15 Sep 2022

Cited by 14 | Viewed by 3108

Abstract

Estimating seabird and pinniped abundance is central to wildlife management and ecosystem monitoring in Antarctica. Unoccupied aerial systems (UAS) can collect images to support monitoring, but manual image analysis is often impractical. Automating target detection using deep learning techniques may improve data acquisition, but different image sensors may affect target detectability and model performance. We compared the performance of automated detection models based on infrared (IR) or color (RGB) images and tested whether IR images, or training data that included annotations of non-target features, improved model performance. For this assessment, we collected paired IR and RGB images of nesting penguins (Pygoscelis spp.) and aggregations of Antarctic fur seals (Arctocephalus gazella) with a small UAS at Cape Shirreff, Livingston Island (60.79 °W, 62.46 °S). We trained seven independent classification models using the Video and Image Analytics for Marine Environments (VIAME) software and created an open-access R tool, vvipr, to standardize the assessment of VIAME-based model performance. We found that the IR images and the addition of non-target annotations had no clear benefits for model performance given the available data. Nonetheless, the generally high performance of the penguin models provided encouraging results for further improving automated image analysis from UAS surveys. Full article

(This article belongs to the Special Issue UAV Design and Applications in Antarctic Research)

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12 pages, 1396 KiB

Open AccessArticle

Demographic Reconstruction of Antarctic Fur Seals Supports the Krill Surplus Hypothesis

by Joseph I. Hoffman, Rebecca S. Chen, David L. J. Vendrami, Anna J. Paijmans, Kanchon K. Dasmahapatra and Jaume Forcada

Genes 2022, 13(3), 541; https://doi.org/10.3390/genes13030541 - 18 Mar 2022

Cited by 15 | Viewed by 5436

Abstract

Much debate surrounds the importance of top-down and bottom-up effects in the Southern Ocean, where the harvesting of over two million whales in the mid twentieth century is thought to have produced a massive surplus of Antarctic krill. This excess of krill may have allowed populations of other predators, such as seals and penguins, to increase, a top-down hypothesis known as the ‘krill surplus hypothesis’. However, a lack of pre-whaling population baselines has made it challenging to investigate historical changes in the abundance of the major krill predators in relation to whaling. Therefore, we used reduced representation sequencing and a coalescent-based maximum composite likelihood approach to reconstruct the recent demographic history of the Antarctic fur seal, a pinniped that was hunted to the brink of extinction by 18th and 19th century sealers. In line with the known history of this species, we found support for a demographic model that included a substantial reduction in population size around the time period of sealing. Furthermore, maximum likelihood estimates from this model suggest that the recovered, post-sealing population at South Georgia may have been around two times larger than the pre-sealing population. Our findings lend support to the krill surplus hypothesis and illustrate the potential of genomic approaches to shed light on long-standing questions in population biology. Full article

(This article belongs to the Special Issue Polar Genomics)

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