scholarly journals Hyperpigmented melanistic skin lesions of smallmouth bass Micropterus dolomieu from the Chesapeake Bay watershed

2020 ◽  
Vol 139 ◽  
pp. 199-212
Author(s):  
VS Blazer ◽  
KT Young ◽  
GD Smith ◽  
AJ Sperry ◽  
LR Iwanowicz
Keyword(s):  
Chesapeake Bay ◽  
Normal Skin ◽  
Transcript Abundance ◽  
Skin Lesions ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Fish Health ◽  
Susquehanna River ◽  
Chesapeake Bay Watershed ◽  
Viral Helicase

Hyperpigmented melanistic skin lesions (HPMLs) of smallmouth bass Micropterus dolomieu are observed in the Potomac and Susquehanna rivers, Chesapeake Bay watershed, USA. Routine, nonlethal population surveys were conducted at 8 sites on the mainstem Susquehanna River and 9 on the Juniata River, a tributary of the Susquehanna River, between 2012 and 2018, and the prevalence of HPMLs was documented. A total of 4078 smallmouth bass were collected from the mainstem Susquehanna River and 6478 from the Juniata River. Lesions were primarily seen in bass greater than 200 mm, and prevalence in the Susquehanna River (8%) was higher (p < 0.001) than in the Juniata River (2%). As part of ongoing fish health monitoring projects, smallmouth bass were collected at additional sites, primarily tributaries of the Susquehanna (n = 758) and Potomac (n = 545) rivers between 2013 and 2018. Prevalence in the Susquehanna River (13%) was higher (p < 0.001) than the Potomac (3%). Microscopically, HPMLs were characterized by an increased number of melanocytes in the epidermis or within the dermis and epidermis. RNAseq analyses of normal and melanistic skin identified 3 unique sequences in HPMLs. Two were unidentified and the third was a viral helicase (E1). Transcript abundance in 16 normal skin samples and 16 HPMLs showed upregulation of genes associated with melanogenesis and cell proliferation in HPMLs. The E1 transcript was detected in 12 of the 16 melanistic areas but in no samples from normal skin. Further research will be necessary to identify the putative new virus and determine its role in melanocyte proliferation.

scholarly journals Perfluoroalkyl Substances in Plasma of Smallmouth Bass from the Chesapeake Bay Watershed

2021 ◽  
Vol 18 (11) ◽  
pp. 5881
Author(s):  
Vicki S. Blazer ◽  
Stephanie E. Gordon ◽  
Heather L. Walsh ◽  
Cheyenne R. Smith
Keyword(s):  
Land Use ◽  
Chesapeake Bay ◽  
Plasma Concentrations ◽  
Fish Tissue ◽  
Smallmouth Bass ◽  
Perfluoroalkyl Substances ◽  
Micropterus Dolomieu ◽  
Population Declines ◽  
Chesapeake Bay Watershed ◽  
Perfluorodecanoic Acid

Smallmouth bass Micropterus dolomieu is an economically important sportfish and within the Chesapeake Bay watershed has experienced a high prevalence of external lesions, infectious disease, mortality events, reproductive endocrine disruption and population declines. To date, no clear or consistent associations with contaminants measured in fish tissue or surface water have been found. Therefore, plasma samples from two sites in the Potomac River and two in the Susquehanna River drainage basins, differing in land-use characteristics, were utilized to determine if perfluoroalkyl substances were present. Four compounds, perfluorooctane sulphonic acid (PFOS), perfluoroundecanoic acid (PFUnA), perfluorodecanoic acid (PFDA) and perfluorododecanoic acid (PFDoA), were detected in every fish. Two additional compounds, perfluorooctane sulphonamide (PFOSA) and perfluorononanoic acid (PFNA), were less commonly detected at lower concentrations, depending on the site. Concentrations of PFOS (up to 574 ng/mL) were the highest detected and varied significantly among sites. No seasonal differences (spring versus fall) in plasma concentrations were observed. Concentrations of PFOS were not significantly different between the sexes. However, PFUnA and PFDoA concentrations were higher in males than females. Both agricultural and developed land-use appeared to be associated with exposure. Further research is needed to determine if these compounds could be affecting the health of smallmouth bass and identify sources.

An Assessment of the Thiamine Status of Smallmouth Bass (Micropterus dolomieu) in the Susquehanna River Watershed

2020 ◽  
Vol 27 (4) ◽  
Author(s):  
Daniel E. Spooner ◽  
Dale C. Honeyfield ◽  
Kristin Boggs ◽  
Dustin Shull ◽  
Tim Wertz ◽  
...  
Keyword(s):  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
River Watershed ◽  
Susquehanna River

scholarly journals Reproductive health and endocrine disruption in smallmouth bass (Micropterus dolomieu) from the Lake Erie drainage, Pennsylvania, USA

2021 ◽  
Vol 194 (1) ◽  
Author(s):  
Heather L. Walsh ◽  
Sean D. Rafferty ◽  
Stephanie E. Gordon ◽  
Vicki S. Blazer
Keyword(s):  
Endocrine Disruption ◽  
Lake Erie ◽  
Agricultural Land ◽  
Biological Effects ◽  
Reproductive Function ◽  
Transcript Abundance ◽  
Smallmouth Bass ◽  
High Rate ◽  
Micropterus Dolomieu ◽  
Endocrine Activity

AbstractSmallmouth bass Micropterus dolomieu were sampled from three sites within the Lake Erie drainage (Elk Creek, Twentymile Creek, and Misery Bay, an embayment in Presque Isle Bay). Plasma, tissues for histopathological analyses, and liver and testes preserved in RNALater® were sampled from 30 smallmouth bass (of both sexes) at each site. Liver and testes samples were analyzed for transcript abundance with Nanostring nCounter® technology. Evidence of estrogenic endocrine disruption was assessed by the presence and severity of intersex (testicular oocytes; TO) and concentrations of plasma vitellogenin in male fish. Abundance of 17 liver transcripts associated with reproductive function, endocrine activity, and contaminant detoxification pathways and 40 testes transcripts associated with male and female reproductive function, germ cell development, and steroid biosynthesis were also measured. Males with a high rate of TO (87–100%) and plasma vitellogenin were noted at all sites; however, TO severity was greatest at the site with the highest agricultural land cover. Numerous transcripts were differentially regulated among the sites and patterns of transcript abundance were used to better understand potential risk factors for estrogenic endocrine disruption. The results of this study suggest endocrine disruption is prevalent in this region and further research would benefit to identify the types of contaminants that may be associated with the observed biological effects.

Black Bass Diversity: Multidisciplinary Science for Conservation

2015 ◽  
Keyword(s):  
Water Quality ◽  
Plasma Concentrations ◽  
Disease Outbreaks ◽  
Endocrine Disrupting Compounds ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Susquehanna River ◽  
Black Bass ◽  
Relationship Of ◽  
Multiple Pathogens

<em>Abstract.</em>—In recent years, wide-scale mortality of young-of-year (YOY) Smallmouth Bass <em>Micropterus dolomieu</em> has affected recruitment in the Susquehanna River and a number of its tributaries. Investigations have determined that these mortality events are associated with changes in various components of water quality in the presence of multiple pathogens. Outbreaks have been characterized by lesions colonized by several species of bacteria, including motile <em>Aeromonas</em> spp., <em>Flavobacterium columnaris</em>, and <em>Pseudomonas aeruginosa</em>. Further, the myxozoan parasite <em>Myxobolus inornatus</em> and trematode metacercariae have been documented in affected fish. Many of the specimens submitted for analysis have also been infected by Largemouth Bass virus. However, the relationship between any particular pathogen and the mortalities remains unclear. Histological analysis of adult bass has demonstrated frequent and severe cases of intersex (i.e., testicular oocytes) and measurable plasma concentrations of vitellogenin in male Smallmouth Bass, suggesting the presence of endocrine-disrupting compounds in the system. It is uncertain what compounds are present or how these compounds may contribute to immunosuppression of YOY Smallmouth Bass, allowing for bacterial and parasite colonization. A complex relationship of several, sublethal stressors are contributing to repeated occurrence of disease outbreaks. Although the Smallmouth Bass is not native to the Susquehanna system, it could be used as a case study as to how changes in water quality and multiple pathogens could pose a threat to conservation of populations of black bass species with low densities and limited distribution.

scholarly journals Draft Genome Sequence of an Adomavirus Associated with Raised Mucoid Skin Lesions on Smallmouth Bass (Micropterus dolomieu)

2020 ◽  
Vol 9 (14) ◽  
Author(s):  
Luke R. Iwanowicz ◽  
Kelsey T. Young ◽  
Cynthia R. Adams ◽  
Vicki S. Blazer ◽  
Geoffrey D. Smith ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Draft Genome ◽  
Skin Lesions ◽  
Smallmouth Bass ◽  
Draft Genome Sequence ◽  
Micropterus Dolomieu ◽  
Content Type ◽  
Circular Genome

Raised mucoid skin lesions have been observed on smallmouth bass (Micropterus dolomieu) for years. Here, we report the draft genome of a novel adomavirus (Micropterus dolomieu adomavirus 2) associated with this disease. The circular genome is 17,561 bp and most similar to that of alpha-adomaviruses.

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