Biodiversity is critical for maintaining ecosystem function but is threatened by increasing anthropogenic pressures. In the Southern Ocean, a highly biologically productive region containing many endemic species, proactive management is urgently needed to mitigate increasing pressures from fishing, climate change, and tourism. Site-based conservation is one important tool for managing the negative impacts of human activities on ecosystems. The Key Biodiversity Area (KBA) Standard is a standardized framework used to define sites vital for the persistence of global biodiversity based on criteria and quantitative thresholds. We used tracking data from 14 species of Antarctic and subantarctic seabirds and pinnipeds from the publicly available Retrospective Analysis of Antarctic Tracking Data (RAATD) data set to define KBAs for a diverse suite of marine predators. We used track2kba, an R package that supports identification of KBAs from telemetry data through identification of highly used habitat areas and estimates of local abundance within sites. We compared abundance estimates at each site with thresholds for KBA criteria A1, B1, and D1 (related to globally threatened species, individual geographically restricted species, and demographic aggregations, respectively). We identified 30 potential KBAs for 13 species distributed throughout the Southern Ocean that were vital for each individual species, population, and life-history stage for which they were determined. These areas were identified as highly used by these populations based on observational data and complement the ongoing habitat modeling and bioregionalization work that has been used to prioritize conservation areas in this region. Although further work is needed to identify potential KBAs based on additional current and future data sets, we highlight the benefits of utilizing KBAs as part of a holistic approach to marine conservation, given their significant value as a global conservation tool.
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RBINS Staff Publications 2024
Clinostomum is a genus of parasitic trematodes found worldwide, infecting a wide range of hosts, including freshwater fishes, snails, birds and occasionally humans. In this study, clinostomid metacercariae were collected from Nile tilapia raised in fish farms in the Upper Tana River region, Kenya. The prevalence of infection was 17.2%, with metacercariae infecting the skin, gills and buccal cavity of the fish. Using light microscopy, scanning electron microscopy (SEM) and molecular methods targeting both nuclear ribosomal (ITS1, 5.8S, ITS2) and mitochondrial (COI) regions, the metacercariae were identified as C. cutaneum, C. phalacrocoracis, C. tilapiae and Euclinostomum heterostomum. The three species of Clinostomum have previously been reported to infect fish or piscivorous birds in Kenya, while this is the first report of E. heterostomum in this country. SEM analysis revealed new ultrastructural features of C. cutaneum, including an excretory pore surrounded by minute spiny papillae, an everted cirrus and dome-shaped papillae on the tegumental area around the genital pore. The cirrus lacked basal papillae, showing morphological variation between the adult and metacercarial stages. Our study, therefore, provides new insights into the phenotypic identification of flukes that may be pathogenic to fishes and humans and, therefore, of scientific and practical importance.
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RBINS Staff Publications 2025
Otoliths, or ear-stones, are calcareous components in the static-acoustic organs of teleost fishes with a characteristic morphology. As such, they are widely used in fisheries because of the information stored in them concerning, for example, environment, age, and so forth. Otoliths of three lethrinid species Lethrinus borbonicus (Valenciennes, 1830), L. lentjan (Lacepède, 1802), and L. mahsena (Forsskål, 1775) were collected from fish caught along the Red Sea coast of Yemen. Images taken with a scanning electron microscope were used to determine their characteristics. Twenty-two characters were defined to describe the shapes of the otoliths. Eleven measurements of distance between selected features were used for a linear regression and multivariate analysis to characterize the species by their otoliths. The results illustrate ontogenetic changes for different age groups based on the recorded shapes. All three species show a linear relationship between the total length and the morphometric measurements. A linear discriminant analysis shows marked differences between the otoliths of the three species and emphasizes the importance of the measured variables. Otoliths of L. lentjan and L. borbinicus are more similar to each other and differ from those of L. mahsena. A comparison with previously published otoliths of the species studied from other areas confirms an intraspecific uniformity across larger geographic distances, making the characters useful for diagnostic purposes.
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RBINS Staff Publications 2022
