Sentinel Species of Marine Ecosystems

Abstract

A vigorous effort to identify and study sentinel species of marine ecosystem in the world’s oceans has developed over the past 50 years. The One Health concept recognizes that the health of humans is connected to the health of animals and the environment. Species ranging from invertebrate to large marine vertebrates have acted as “sentinels” of the exposure to environmental stressors and health impacts on the environment that may also affect human health. Sentinel species can signal warnings, at different levels, about the potential impacts on a specific ecosystem. These warnings can help manage the abiotic and anthropogenic stressors (e.g., climate change, chemical and microbial pollutants, marine litter) affecting ecosystems, biota, and human health. The effects of exposure to multiple stressors, including pollutants, in the marine environment may be seen at multiple trophic levels of the ecosystem. Attention has focused on the large marine vertebrates, for several reasons. In the past, the use of large marine vertebrates in monitoring and assessing the marine ecosystem has been criticized. The fact that these species are pelagic and highly mobile has led to the suggestion that they are not useful indicators or sentinel species. In recent years, however, an alternative view has emerged: when we have a sufficient understanding of differences in species distribution and behavior in space and time, these species can be extremely valuable sentinels of environmental quality. Knowledge of the status of large vertebrate populations is crucial for understanding the health of the ecosystem and instigating mitigation measures for the conservation of large vertebrates. For example, it is well known that the various cetacean species exhibit different home ranges and occupy different habitats. This knowledge can be used in “hot spot” areas, such as the Mediterranean Basin, where different species can serve as sentinels of marine environmental quality. Organisms that have relatively long life spans (such as cetaceans) allow for the study of chronic diseases, including reproductive alterations, abnormalities in growth and development, and cancer. As apex predators, marine mammals feed at or near the top of the food chain. As the result of biomagnification, the levels of anthropogenic contaminants found in the tissues of top predators and long-living species are typically high. Finally, the application of consistent examination procedures and biochemical, immunological, and microbiological techniques, combined with pathological examination and behavioral analysis, has led to the development of health assessment methods at the individual and population levels in wild marine mammals. With these tools in hand, investigators have begun to explore and understand the relationships between exposures to environmental stressors and a range of disease end points in sentinel species (ranging from invertebrates to marine mammals) as an indicator of ecosystem health and a harbinger of human health and well-being.

Chasing phthalates in tissues of marine turtles from the Mediterranean sea

“…ingestion and permanence in the gastrointestinal tract of micro and macroplastics). These aspects have been considered also in view of recent studies conducted in the Mediterranean Sea on the presence of plastics and microplastics and their potential impact on the marine organisms (de Lucia et al, 2014;Fossi et al, 2014Fossi et al, , 2017Lazar and Gracan 2011;Guerranti et al, 2017;Campani et al, 2013).…”

“…This descriptor is used to evaluate whether the Good Environmental Status (GES) is being achieved (Galgani et al, 2013). Therefore, sea turtles and marine mammals can be considered as appropriate sentinel species to study how marine litter can interact with marine animals (Fossi and Panti, 2017). The three most common sea turtles species presents in the Mediterranean Sea are listed by IUCN as vulnerable or endangered species also due to the negative impact of accidental ingestion of plastics (bags, fragments, fishing lines, etc.)…”

Drones reveal spatial patterning of sympatric Alaskan pinniped species and drivers of their local distributions

“…Simultaneously, climate change exposes arctic fauna to novel threats such as invasive species (Chan et al 2018), disease vectors (Parkinson et al 2014) and anthropogenic contaminants (Macdonald et al 2005), threatening arctic food webs and the human cultures and economies that depend on them. Monitoring of sentinel species, such as marine mammals, at ecologically important or vulnerable sites can reveal the occurrence and severity of these ecological changes when they occur (Bossart 2010;Fossi and Panti 2017).…”

Peruvian Fur Seals as Archivists of El Niño Southern Oscillation Effects

“…Peruvian pinnipeds are distinctly vulnerable during these strong magnitude ENSO episodes (Oliveira, 2011). These marine mammals serve as sentinel species, indicative of ecosystem health in an environment at the center of fluctuating ENSO conditions (Fossi and Panti, 2017). The feeding ecology and movements of these pinnipeds are of substantial interest as ENSO events continue to intensify in both frequency and magnitude (Sepúlveda et al, 2014).…”