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Higueruelo A, Constenla M, Padrós F, Sánchez-Marín P, Carrassón M, Soler-Membrives A, Dallarés S. Coping with current impacts: The case of Scyliorhinus canicula in the NW Mediterranean Sea and implications for human consumption. MARINE POLLUTION BULLETIN 2024; 201:116200. [PMID: 38430679 DOI: 10.1016/j.marpolbul.2024.116200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/05/2024]
Abstract
The small-spotted catshark (Scyliorhinus canicula) is a bottom-dwelling elasmobranch that represents the most discarded catch in terms of biomass in the Catalan coast (NW Mediterranean). Potential impacts affecting its population and food safety implications have been assessed in three localities along the Catalan coast. Distinct indicators were integrated, such as biological data, ingested anthropogenic items (plastic and cellulose-like items), parasitological indices, trace metal concentrations and histopathology using liver as target organ. Although high ingestion rates of fibres and levels of some heavy metals, they do not seem negatively affected by any major pathology nor by the current levels of pollutants. Small-scale differences among localities and depths were found and discussed. No zoonotic parasites were found. Encysted larvae of Grillotia adenoplusia and, above all, the levels of Hg found in the musculature, that are well over the European Commission limits, rise concerns regarding human consumption of S. canicula in this region.
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Affiliation(s)
- Andrea Higueruelo
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Maria Constenla
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Francesc Padrós
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Paula Sánchez-Marín
- Centro Oceanográfico de Vigo, Instituto Español de Oceanografía (IEO-CSIC), Subida a Radio Faro, s/n, 36390 Vigo, Spain
| | - Maite Carrassón
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Anna Soler-Membrives
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain.
| | - Sara Dallarés
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
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Edwards ML, Schaefer AM, McFarland M, Fire S, Perkins CR, Ajemian MJ. Detection of numerous phycotoxins in young bull sharks (Carcharhinus leucas) collected from an estuary of national significance. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159602. [PMID: 36272472 DOI: 10.1016/j.scitotenv.2022.159602] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 10/02/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Florida's Indian River Lagoon (IRL) has experienced large-scale, frequent blooms of toxic harmful algae in recent decades. Sentinel, or indicator, species can provide an integrated picture of contaminants in the environment and may be useful to understanding phycotoxin prevalence in the IRL. This study evaluated the presence of phycotoxins in the IRL ecosystem by using the bull shark (Carcharhinus leucas) as a sentinel species. Concentrations of phycotoxins were measured in samples collected from 50 immature bull sharks captured in the IRL between 2018 and 2020. Ultra-performance liquid chromatography/tandem mass spectrometry was used to measure toxins in shark gut contents, plasma, and liver. Analysis of samples (n = 123) demonstrated the presence of multiple phycotoxins (microcystin, nodularin, teleocidin, cylindrospermopsin, domoic acid, okadaic acid, and brevetoxin) in 82 % of sampled bull sharks. However, most detected toxins were in low prevalence (≤25 % of samples, per sample type). This study provides valuable baseline information on presence of multiple phycotoxins in a species occupying a high trophic position in this estuary of national significance.
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Affiliation(s)
- Michelle L Edwards
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 U.S. 1 North, Fort Pierce, FL 34946, USA.
| | - Adam M Schaefer
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 U.S. 1 North, Fort Pierce, FL 34946, USA; Abt Associates, 6130 Executive Blvd, Rockville, MD 20852, USA
| | - Malcolm McFarland
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 U.S. 1 North, Fort Pierce, FL 34946, USA
| | - Spencer Fire
- Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32951, USA
| | - Christopher R Perkins
- Center for Environmental Sciences and Engineering, University of Connecticut, 3107 Horsebarn Hill Road, U-4210, Storrs, CT 06269, USA
| | - Matthew J Ajemian
- Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 U.S. 1 North, Fort Pierce, FL 34946, USA
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de Lima CL, Morales-Gamba RD, Malcher Neto TS, Barcellos JFM, Heinzmann BM, Schmidt D, Baldisserotto B, Marcon JL. Eugenol and Lippia alba essential oils as effective anesthetics for the Amazonian freshwater stingray Potamotrygon wallacei (Chondrichthyes, Potamotrygonidae). FISH PHYSIOLOGY AND BIOCHEMISTRY 2021; 47:2101-2120. [PMID: 34807332 DOI: 10.1007/s10695-021-01029-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
This study assessed the potential of eugenol and the essential oil of Lippia alba (EOLA) in providing suitable anesthetic induction and recovery times, and their consequent effects on the blood and respiratory physiology, as well as the gill architecture of an Amazonian freshwater stingray, Potamotrygon wallacei, shortly after reaching the recovery and 48 h later. Juveniles of P. wallacei were exposed to increasing concentrations of eugenol (75, 100, 125, and 150 µL L-1) and EOLA (150, 175, 200, and 225 µL L-1) in an immersion bath. Anesthetic induction was found to be faster with the use of eugenol compared to EOLA. On the other hand, the stingrays anesthetized with eugenol displayed a longer recovery time than those exposed to EOLA. The highest concentrations of eugenol caused moderate to severe histological changes in the gills. No significant changes were found for hematocrit and plasma energy metabolites in the stingrays anesthetized with all concentrations of both eugenol and EOLA shortly after reaching the recovery from the ansthesia, when compared to those recovered after 48 h. Investigations regarding the potential use of these natural anesthetics are unprecedented for freshwater stingray species, and 200 μL L-1 EOLA is recommended as the most suitable anesthetic for use in juveniles of P. wallacei.
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Affiliation(s)
- Cristiano Lopes de Lima
- Programa de Pós-Graduação em Aquicultura, Universidade Nilton Lins, Av. Prof. Nilton Lins, 3259, 69058-030, Manaus, Amazonas, Brasil
- Instituto Federal de Educação, Ciência e Tecnologia do Amazonas - IFAM, Campus Manaus Zona Leste- CMZL, Av. Cosme Ferreira, 8045, 69083-000, Manaus, Amazonas, Brasil
| | - Ruben Dario Morales-Gamba
- Programa de Pós-Graduação em Zoologia, Universidade Federal do Amazonas (UFAM), Av. Rodrigo Octavio 1200, 6200, 69080-900, Manaus, Amazonas, Brasil
| | - Thiago Santana Malcher Neto
- Instituto Federal de Educação, Ciência e Tecnologia do Amazonas - IFAM, Campus Manaus Zona Leste- CMZL, Av. Cosme Ferreira, 8045, 69083-000, Manaus, Amazonas, Brasil
| | - José Fernando Marques Barcellos
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal Do Amazonas (UFAM). Av. Gen. Rodrigo Octávio, 6200 Coroado I. 69080-900, Manaus, Amazonas, Brasil
| | - Berta Maria Heinzmann
- Departamento de Farmácia Industrial, Universidade Federal de Santa Maria, Av. Roraima, 1000, 97105-900, Santa Maria, Rio Grande do Sul, Brasil
| | - Denise Schmidt
- Departamento de Ciências Agronômicas e Ambientais, Universidade Federal de Santa Maria, Campus de Frederico Westphalen, Frederico Westphalen, Rio Grande do Sul, Brasil
| | - Bernardo Baldisserotto
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Santa Maria, Av. Roraima, 1000, 97105-900, Santa Maria, Rio Grande do Sul, Brasil
| | - Jaydione Luiz Marcon
- Programa de Pós-Graduação em Aquicultura, Universidade Nilton Lins, Av. Prof. Nilton Lins, 3259, 69058-030, Manaus, Amazonas, Brasil.
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Amazonas (UFAM). Av. Gen. Rodrigo Octávio, 6200. Coroado I. 69080-900. Manaus, Amazonas, Brasil.
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Borucinska J, Adams DH, Frazier BS. Histologic Observations of Dermal Wound Healing in a Free-Ranging Blacktip Shark from the Southeastern U.S. Atlantic Coast: A Case Report. JOURNAL OF AQUATIC ANIMAL HEALTH 2020; 32:141-148. [PMID: 32896007 DOI: 10.1002/aah.10113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 08/30/2020] [Indexed: 06/11/2023]
Abstract
Despite indications that sharks have an exceptional capacity to heal from traumatic injuries, no detailed microscopic observations of integumental wounds have been reported for sharks. This study details the histopathological features of such wounds in a free-ranging shark. An adult male Blacktip Shark Carcharhinus limbatus was collected in 2017 during fisheries-independent sampling efforts in the coastal southeastern U.S. Atlantic. The shark had numerous lesions on his head, torso, and left pectoral fin that were compatible with shark bites. Representative samples from two wounds on the head were examined by light microscopy. The epidermal changes included hyperplasia and hypertrophy; intracellular edema; and the absence of goblet cells, denticles, and chromatophores. In the dermis, fibrinocellular exudation, granulation tissue, and marked skeletal muscle necrosis and regeneration were observed. The above features were comparable to wound healing in bony fish, albeit minor differences were found. Although this case documents exceptionally good regeneration of skeletal muscle in the shark, we found no evidence of unique morphological healing patterns. Further studies on wound healing are needed because recent molecular and genetic findings do suggest evolutionary adaptations enhancing healing in sharks.
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Affiliation(s)
- Joanna Borucinska
- Department of Biology, University of Hartford, 200 Bloomfield Avenue, West Hartford, Connecticut, 06117, USA
| | - Douglas H Adams
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, 1220 Prospect Avenue, Suite 285, Melbourne, Florida, 32901, USA
| | - Bryan S Frazier
- South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, South Carolina, 29412, USA
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Malinowski CR, Perrault JR, Coleman FC, Koenig CC, Stilwell JM, Cray C, Stacy NI. The Iconic Atlantic Goliath Grouper ( Epinephelus itajara): A Comprehensive Assessment of Health Indices in the Southeastern United States Population. Front Vet Sci 2020; 7:635. [PMID: 33102560 PMCID: PMC7546827 DOI: 10.3389/fvets.2020.00635] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 08/04/2020] [Indexed: 01/10/2023] Open
Abstract
The Atlantic Goliath Grouper (Epinephelus itajara) population has rebounded from near extinction to an international status as vulnerable due in part to regional species recovery efforts. The southeastern US population has been recovering with the main spawning locations off the coasts of Florida. Despite their economic importance to the catch-and-release fishery and the dive industry, and their ecological importance as ecosystem engineers resulting in positive impacts on reefs and species richness, baseline health assessment information is very limited in this species to date. The objectives of this study were to: (1) establish reference intervals for hematological and plasma biochemical analytes, and report immune function, oxidative stress, and vitellogenin in mature males and females; (2) evaluate total length, age, and sex in relation to blood analytes in juvenile and mature fish; (3) assess analytes across sampled months in mature male and female fish; and (4) describe the typical light microscopy findings in liver and gill biopsies, including quantitative assessment of pigmented macrophage aggregates. Health indices are reported as reference intervals when applicable, or otherwise descriptively. Blood analyte correlations with length and age, sex differences, and comparisons across months provided relevant physiological considerations, including differences in protein/energy metabolism, tissue growth, sexual maturation, active reproduction, and antigenic stimulation. Liver histology identified changes associated with life stage, active reproduction, or of subclinically to clinically insignificant infectious and/or inflammatory processes. Hepatocellular vacuolation and pigmented macrophage aggregates were prominent. Pigmented macrophage aggregates correlated with total length, presumably from continuous antigenic stimulation and/or metabolic changes as fish grow. Gill histological findings were subtle. The data presented herein provide an essential baseline assessment of a suite of health variables in an iconic marine teleost species, serves as a springboard for future studies relevant to conservation physiology, and allows for population-level applications for conservation management and policy.
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Affiliation(s)
- Christopher R Malinowski
- Florida State University Coastal and Marine Laboratory, St. Teresa, FL, United States.,Department of Biological Science, Florida State University, Tallahassee, FL, United States.,Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, United States
| | - Justin R Perrault
- Mote Marine Laboratory, Sarasota, FL, United States.,Loggerhead Marinelife Center, Juno Beach, FL, United States
| | - Felicia C Coleman
- Florida State University Coastal and Marine Laboratory, St. Teresa, FL, United States
| | - Christopher C Koenig
- Florida State University Coastal and Marine Laboratory, St. Teresa, FL, United States
| | - Justin M Stilwell
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Carolyn Cray
- Division of Comparative Pathology, Department of Pathology & Laboratory Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Nicole I Stacy
- Division of Comparative Pathology, Department of Pathology & Laboratory Medicine, University of Miami Miller School of Medicine, Miami, FL, United States.,Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
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6
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Sayed AEDH, Abd-Elkareem M, Abou Khalil NS. Immunotoxic effects of 4-nonylphenol on Clarias gariepinus: Cytopathological changes in hepatic melanomacrophages. AQUATIC TOXICOLOGY 2019; 207:83-90. [PMID: 30537592 DOI: 10.1016/j.aquatox.2018.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 12/02/2018] [Accepted: 12/02/2018] [Indexed: 02/07/2023]
Abstract
Melanomacrophage centres (MMCs) play a key role in the immune response in fish. They are considered sensitive bio-monitoring structures with roles in the assessment of toxicant impacts. The aim of this study was to examine the potential histopathological effect of 4-nonylphenol (4-NP) on hepatic MMCs in Clarias gariepinus. To achieve this objective, adult male fish were divided randomly and equally into two groups: a control group and a group that was exposed to 4-NP (dissolved in water at a dose of 0.1 mg/L) for 21 days. The 4-NP-intoxicated hepatic MMCs contained numerous necrotic macrophages. Superoxide dismutase 2 was immuno-expressed in the hepatic MMCs in both groups, with no significant difference. Histomorphometric examination revealed that the sizes and numbers of MMCs were dramatically higher in the livers of 4-NP-exposed C. gariepinus than in control fish. Following 4-NP challenge, in the liver, the abundance of lipofuscin and haemosiderin pigments increased, and single-pigmented macrophages, aggregated groups of deformed red blood cells (RBCs) and macrophages were present near blood vessels and hepatic sinusoids. These results reveal that 4-NP exerts immunological effects on hepatic MMCs in C. gariepinus and support the utility of MMCs as a cytological biomarker for aquatic exposure to 4-NP.
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Affiliation(s)
- Alaa El-Din H Sayed
- Zoology Department, Faculty of Science, Assiut University, 71516 Assiut, Egypt.
| | - Mahmoud Abd-Elkareem
- Anatomy, Histology and Embryology Department, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt
| | - Nasser S Abou Khalil
- Medical Physiology Department, Faculty of Medicine, Assiut University, Assiut, Egypt
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Nau MR, Gardiner DW, Nilson E, Schmitt TL, Nollens HH, St Leger J. Cutaneous malignant melanoma in a Haller's round ray Urobatis halleri. DISEASES OF AQUATIC ORGANISMS 2016; 120:245-250. [PMID: 27503921 DOI: 10.3354/dao03029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Multiple black raised nodular masses were noted on the dorsal surface of an adult male Haller's round ray Urobatis halleri. Biopsy of 2 masses was performed, and histopathology revealed proliferative sheets of melanocytes exhibiting mild anisocytosis and anisokaryosis, supporting a diagnosis of malignant melanoma. Approximately 2 mo following the biopsy procedure, the round ray became acutely anorexic and was found dead in its enclosure. A full necropsy was performed, and tissues were submitted for histopathology. The black raised nodular masses again exhibited histologic features of a melanoma. In addition to the nodular masses present, multiple flat areas of increased pigmentation were also present throughout the course of the case and were not suggestive of neoplasia histologically. The transformation of benign to malignant neoplasia has been well described in other species and may have played a role in the development of multiple tumors in this case.
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Affiliation(s)
- Melissa R Nau
- National Marine Mammal Foundation, San Diego, California 92106, USA
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Administration of a Polyphenol-Enriched Feed to Farmed Sea Bass (Dicentrarchus labrax L.) Modulates Intestinal and Spleen Immune Responses. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:2827567. [PMID: 26779301 PMCID: PMC4686725 DOI: 10.1155/2016/2827567] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 08/27/2015] [Accepted: 09/02/2015] [Indexed: 01/30/2023]
Abstract
Farmed fish are exposed to a continuous antigenic pressure by microbial and environmental agents, which may lead to a condition of chronic inflammation. In view of the notion that polyphenols, largely contained in fruits and vegetables, are endowed with antioxidant and anti-inflammatory activities, farmed sea bass (Dicentrarchus labrax L.) have been administered with red grape polyphenol-enriched feed. Polyphenols were extracted from the seeds of Canosina Nero di Troia Vitis vinifera and mixed with conventional feed at two different concentrations (100 and 200 mg/kg, resp.). Fish samples collected at days 223 and 273, respectively, were evaluated for intestinal and spleen cytokine release as well as for spleen macrophage (MØ) and melanomacrophage center (MMC) areas and distribution. Data will show that in treated fish decrease of intestinal interleukin- (IL-) 1β and IL-6 and increase of splenic interferon- (IFN-) γ occur. On the other hand, in the spleen reduction of MØ number seems to parallel increase in MMCs. Collectively, these data suggest that polyphenol-administered sea bass generate lower levels of intestinal proinflammatory cytokines, while producing larger amounts of spleen IFN-γ, as an expression of a robust and protective adaptive immune response. Increase of MMCs corroborates the evidence for a protective spleen response induced by feed enriched with polyphenols.
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Adams DH, Borucinska JD, Maillett K, Whitburn K, Sander TE. Mortality due to a retained circle hook in a longfin mako shark Isurus paucus (Guitart-Manday). JOURNAL OF FISH DISEASES 2015; 38:621-628. [PMID: 24974904 DOI: 10.1111/jfd.12277] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 05/08/2014] [Accepted: 05/16/2014] [Indexed: 06/03/2023]
Abstract
A female longfin mako shark Isurus paucus (Guitart-Manday, 1966) was found moribund on the Atlantic Ocean beach near Canaveral National Seashore, Florida; the shark died shortly after stranding. Macroscopic lesions included a partially healed bite mark on the left pectoral fin, a clefted snout, pericardial effusion and a pericardial mass surrounding a 12/0 circle fishing hook. The heart, pericardial mass, gills, ovary, oviduct, shell gland, epigonal organ, liver, kidney and intrarenal and interrenal glands were processed for histopathology and examined by brightfield microscopy. Microscopic examination revealed chronic proliferative and pyogranulomatous pericarditis and myocarditis with rhabdomyolysis, fibrosis and thrombosis; scant bacteria and multifocal granular deposits of iron were found intralesionally. In addition, acute, multifocal infarcts within the epigonal organ and gill filaments were found in association with emboli formed by necrocellular material. The ovary had high numbers of atretic follicles, and the liver had diffuse, severe hepatocellular degeneration, multifocal spongiosis and moderate numbers of melanomacrophage cells. This report provides evidence of direct mortality due to systemic lesions associated with retained fishing gear in a prohibited shark species. Due to the large numbers of sharks released from both recreational and commercial fisheries worldwide, impact of delayed post-release mortality on shark populations is an important consideration.
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Affiliation(s)
- D H Adams
- Cape Canaveral Scientific Inc., Melbourne Beach, FL, USA
| | - J D Borucinska
- Department of Biology, University of Hartford, West Hartford, CT, USA
| | - K Maillett
- Department of Biology, University of Hartford, West Hartford, CT, USA
| | - K Whitburn
- Department of Biology, University of Hartford, West Hartford, CT, USA
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The spleen of the African lungfish Protopterus annectens: freshwater and aestivation. Cell Tissue Res 2012; 350:143-56. [DOI: 10.1007/s00441-012-1462-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 05/31/2012] [Indexed: 10/28/2022]
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Paetow LJ, Daniel McLaughlin J, Cue RI, Pauli BD, Marcogliese DJ. Effects of herbicides and the chytrid fungus Batrachochytrium dendrobatidis on the health of post-metamorphic northern leopard frogs (Lithobates pipiens). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 80:372-80. [PMID: 22520452 DOI: 10.1016/j.ecoenv.2012.04.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 04/02/2012] [Accepted: 04/03/2012] [Indexed: 05/31/2023]
Abstract
Effects of exposure to contaminants such as pesticides along with exposure to pathogens have been listed as two major contributors to the global crisis of declining amphibian populations. These two factors have also been linked in explanations of the causes of these population declines. We conducted a combined exposure experiment to test the hypothesis that exposure to two agricultural herbicides would increase the susceptibility of post-metamorphic northern leopard frogs (Lithobates pipiens) to the amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd). We assessed the independent and interactive effects of these exposures on the health and survival of the frogs. Wild-caught frogs underwent a 21-day exposure to a nominal concentration of either 2.1 μg/L atrazine (Aatrex(®) Liquid 480) or 100 μg a.e./L glyphosate (Roundup(®) Original), followed by Bd, and then were observed until 94 days post-initial exposure to the herbicides. Actual levels of atrazine were between 4.28 ± 0.04 μg/L and 1.70 ± 0.26 μg/L while glyphosate degraded from 100 μg a.e./L to approximately 7 μg a.e./L within 6 days of initial exposure to the herbicides. Compared to controls, the glyphosate formulation reduced the snout-vent length of frogs during the pesticide exposure (at Day 21), and the atrazine formulation reduced gain in mass up to Day 94. No treatment affected survival, splenosomatic or hepatosomatic indices, the densities and sizes of hepatic and splenic melanomacrophage aggregates, the density and size of hepatic granulomas, proportions of circulating leucocytes, the ratio of neutrophils to lymphocytes, or the ratio of leucocytes to erythrocytes. Histological assessment of samples collected at Day 94 revealed no evidence of Bd infection in any Bd-exposed frogs, while real-time PCR detected only one case of light infection in a single atrazine- and Bd-exposed frog. Frogs exposed to Bd shed their skin significantly more frequently than Bd-unexposed frogs, which may have helped them resist or clear infection, and could explain why no interaction between the herbicides and Bd was detected. The results suggest that these frogs were resistant to Bd infection and that pre-exposure to the herbicides did not alter this resistance. The effects seen on the growth following herbicide exposure is a concern, as reduced growth can lower the reproductive success and survival of the amphibians.
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Affiliation(s)
- Linda J Paetow
- Department of Biology, Concordia University, 7141 Sherbrooke St. W., Montreal, Quebec, Canada H4B 1R6
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