Immunity and health of two wild marine fishes naturally exposed to anthropogenic pollution

Per- and polyfluoroalkyl substances (PFAS) in little penguins and associations with urbanisation and health parameters

Per- and Polyfluoroalkyl substances (PFAS) are increasingly detected in wildlife and present concerning and unknown health risks. While there is a growing body of literature describing PFAS in seabird species, knowledge from temperate Southern Hemisphere regions is lacking. Little penguins (Eudyptula minor) can nest and forage within heavily urbanised coastal environments and hence may be at risk of exposure to pollutants. We analysed scat contaminated nesting soils (n = 50) from 17 colonies in lutruwita/Tasmania for 16 PFAS, plasma samples (n = 45) from nine colonies, and three eggs for 49 PFAS. We detected 14 PFAS across the sample types, with perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) most commonly detected. Mean concentration of PFOS in plasma was 2.56 ± 4.3 ng/mL ( Collapse

Key Words

• Ecotoxicology
• Genotoxicity
• Human impacts
• Seabird sentinels
• Wildlife health

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MESH Headings

• Male
• Female
• Animals
• Spheniscidae
• Urbanization
• Alkanesulfonic Acids/analysis
• Environmental Pollutants/analysis
• Fluorocarbons/analysis
• Soil
• Sulfonic Acids

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Affiliation(s)

Melanie R Wells Department of Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart 7001, Tasmania, Australia; Institute for Marine and Antarctic Studies, Battery Point 7004, Tasmania, Australia.
Timothy L Coggan Environment Protection Authority Victoria, 200 Victoria Street, Carlton 3053, Victoria, Australia; ADE Consulting Group, U 4/95 Salmon Street, Port Melbourne 3207, Victoria, Australia
Gavin Stevenson Australian Ultra-Trace Laboratory, National Measurement Institute, North Ryde 2113, New South Wales, Australia
Navneet Singh ADE Consulting Group, U 4/95 Salmon Street, Port Melbourne 3207, Victoria, Australia
Matthew Askeland ADE Consulting Group, U 4/95 Salmon Street, Port Melbourne 3207, Victoria, Australia
Mary-Anne Lea Institute for Marine and Antarctic Studies, Battery Point 7004, Tasmania, Australia; Centre for Marine Socioecology, University of Tasmania, Hobart 7001, Tasmania, Australia
Annie Philips Wildlife Veterinary Consultant, Hobart 7000, Tasmania, Australia
Scott Carver Department of Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart 7001, Tasmania, Australia; Odum School of Ecology, University of Georgia, GA, USA 30602; Center for the Ecology of Infectious Diseases, University of Georgia, GA, USA 30602

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Links between reproduction and immunity in two sympatric wild marine fishes

According to life-history theory, limited resources can result in trade-offs between costly physiological functions. Particularly, it can be expected that individuals present lower immune function, or an alternative immunological strategy, during their reproductive compared to their non-reproductive season. Here we investigate the link between reproduction and immunity in two sympatric marine fish species, the rockfish Sebastes oculatus and the sandperch Pinguipes brasilianus. The results showed lower values of total white blood cells and spleen index, but higher levels of natural antibodies (only in females) in reproductive rockfish compared to non-reproductive ones. On the other hand, reproductively active sandperch showed lower levels of natural antibodies and a higher neutrophil to lymphocyte ratio and spleen index (only in males), compared to non-reproductive ones. Also, negative correlations between reproductive and immune parameters were observed in female rockfish at the individual level, but not in sandperch. Our results are consistent with the presence of different immunological strategies in reproductive and non-reproductive periods, with patterns that appear to be species-specific. This specificity suggests that various aspects of immunity might respond differentially to resource limitation, which could be associated with the disparate life-history strategies of the studied species. Alternatively, though not exclusively, the observed patterns could be driven by abiotic factors that characterize the reproductive season of each species (i.e., winter for rockfish, summer for sandperch). Our study contributes to ecoimmunological knowledge on free-living fish and highlights that detection of trade-offs can depend on the combination of study species, season, sex, and specific immune components measured.

Anthropogenic impact on the reproductive health of two wild Patagonian fish species with differing reproductive strategies

A particularly concerning outcome of environmental pollution is the disturbance of reproductive processes. However, studies on the impacts of pollution on the reproductive health of fish inhabiting South American environments are limited. We studied the impact of anthropogenic pollution on the reproductive health of two sympatric Patagonian marine fish species with different reproductive strategies: the live-bearing rockfish Sebastes oculatus and the egg-laying Brazilian sandperch Pinguipes brasilianus. Our findings reveal that both species presented some degree of reproductive disturbance when inhabiting an affected site, but the specific alterations differed depending on the species, sex, and season. During the reproductive season, 17β-estradiol levels were elevated in females of both species living in polluted areas, while no differences in androgen levels were observed in either species or season. The gonadosomatic index (GSI) was affected in both sexes of S. oculatus during the non-reproductive season, while the gonadal stages were mainly affected in both sexes of P. brasilianus. No signs of intersex condition were observed. Our results highlight the importance of including diverse reproductive parameters to better understand anthropogenic effects on wild animals. Long-term studies including other fish species and including offspring (to evaluate possible transgenerational effects) will be necessary to determine the consequences of the documented reproductive alterations, particularly whether fish species inhabiting Patagonian marine reef areas will be able to reproductively adapt to increasing marine anthropogenic disturbances.

Environmentally relevant concentrations of fenvalerate induces immunotoxicity and reduces pathogen resistance in Chinese rare minnow (Gobiocypris rarus)

Fenvalerate is a broadly used type II pyrethroid with a potential toxic effect in fish. However, information on the immunotoxicity of fenvalerate in fish is scarce. Here, to discover the immunotoxicity of fenvalerate and its underlying mechanism in fish, adult Chinese rare minnow was exposed to fenvalerate at 0, 0.3, 1, and 3 μg/L for 28 days and then subjected to Pseudomonas fluorescens (P. fluorescens) challenge. Fenvalerate induced significant pathological changes, with disintegration of cell boundaries in the intestine, epithelial hyperplasia in gills, and vacuolation of hepatocytes at 3 μg/L treatment. Additionally, the pathological characteristics were more serious during P. fluorescens infection after fenvalerate exposure. A significant increase in neutrophil counts was observed after 3 μg/L fenvalerate exposure for 28 days (p < 0.05), whereas significantly increased monocyte and neutrophil counts and greatly decreased lymphocyte counts were detected at 24 h post-injection (hpi) with P. fluorescens (p < 0.05). Furthermore, obvious decreases in LYS, IgM, ALP, and C3 levels were detected in plasma after 3 μg/L fenvalerate exposure for 28 days, which was consistent with the results at 24 and 48 hpi. Notably, fish exposed to fenvalerate suppressed the transcription of TLR-NF-κB signaling pathway-relevant genes in response to P. fluorescens, accompanied by high mortalities and bacterial loads. Therefore, our results demonstrate that fenvalerate at environmentally relevant concentrations caused immunotoxicity in fish. This study highlights the importance of considering the combined effects of chemicals and pathogens to refine our ability to predict the effects of environmental contaminants on aquatic organisms.

Epitheliocystis in wild marine fishes and its relation with anthropogenic pollution

Epitheliocystis is a fish disease with recorded in increasing numbers globally. Here we show that (a) pollution-exposed wild marine fishes have higher infection prevalence than nonexposed individuals from reference sites, suggesting that anthropogenic pollution predisposes individuals to this disease in natural systems, (b) the effect of pollution on infection status did not vary significantly between two sympatric fish species, and (c) infected and noninfected individuals from both species did not differ significantly in selected immune and general-health parameters, a result that deserves further study with increased sample sizes.