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Digenean parasites of shore crabs, Carcinus maenas / ALEXANDER BEDFORD

Swansea University Author: ALEXANDER BEDFORD

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Abstract

This study reports on the prevalence, intensity, and species identification of digenean trematode infections in shore crabs (Carcinus maenas) found at two intertidal survey sites (Mumbles Head and Oxwich Bay) in the Bristol Channel, U.K. between February, and August 2024. Crabs were assessed for the...

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Published: Swansea University, Wales, UK 2025
Institution: Swansea University
Degree level: Master of Research
Degree name: MRes
Supervisor: Rowley, A. F., and Davies, C. E.
URI: https://cronfa.swan.ac.uk/Record/cronfa69872
first_indexed 2025-07-03T10:04:57Z
last_indexed 2025-07-04T06:42:53Z
id cronfa69872
recordtype RisThesis
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spelling 2025-07-03T11:09:03.3382523 v2 69872 2025-07-03 Digenean parasites of shore crabs, Carcinus maenas c3743e7b62a799700b926af3015aa656 ALEXANDER BEDFORD ALEXANDER BEDFORD true false 2025-07-03 This study reports on the prevalence, intensity, and species identification of digenean trematode infections in shore crabs (Carcinus maenas) found at two intertidal survey sites (Mumbles Head and Oxwich Bay) in the Bristol Channel, U.K. between February, and August 2024. Crabs were assessed for the presence and intensity of trematode infections by the microscopic examination of the hepatopancreas. The metacercariae species identification resulted from the combined use of morphological and PCR-based methods, specifically the 28S rDNA gene. Encysted metacercariae presented in two distinct forms, spherical and asymmetrical, which were shown to be Microphallus similis and M. primas, respectively. A high prevalence and intensity of M. similis metacercariae was found in shore crab populations from both locations throughout the duration of the study. Conversely, M. primas metacercariae were only identified in a limited number of crabs and at low infection intensities during June and August sampling. No cellular host immune responses were observed.Binomial logistic regression models revealed size and colouration to be significant factors in trematode presence at Oxwich Bay only. Additionally, larger/older shore crabs were found to harbour more metacercarial cysts, with larger metacercariae observed in crabs from Mumbles Head. Overall, the findings of this study highlight the widespread prevalence of M. similis infections in shore crab populations at both intertidal survey sites, with notable size and location-specific variations in infection intensity. Additionally, the results underscore the importance of conducting a long-term study to better understand the seasonal dynamics of M. similis and M. primas infections in shore crabs. E-Thesis Swansea University, Wales, UK Crabs, Carcinus maenas, trematodes, Microphallidae, Microphallus similis, Microphallus primas 12 5 2025 2025-05-12 A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. COLLEGE NANME COLLEGE CODE Swansea University Rowley, A. F., and Davies, C. E. Master of Research MRes 2025-07-03T11:09:03.3382523 2025-07-03T10:59:53.1759205 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Biosciences ALEXANDER BEDFORD 1 69872__34647__cfb756187ea24092b96a3e6d83a17358.pdf 2024_Bedford_A.final.69872.pdf 2025-07-03T11:04:19.8925527 Output 27084150 application/pdf E-Thesis – open access true Copyright: The author, Alexander Thomas Bedford, 2024 true eng
title Digenean parasites of shore crabs, Carcinus maenas
spellingShingle Digenean parasites of shore crabs, Carcinus maenas
ALEXANDER BEDFORD
title_short Digenean parasites of shore crabs, Carcinus maenas
title_full Digenean parasites of shore crabs, Carcinus maenas
title_fullStr Digenean parasites of shore crabs, Carcinus maenas
title_full_unstemmed Digenean parasites of shore crabs, Carcinus maenas
title_sort Digenean parasites of shore crabs, Carcinus maenas
author_id_str_mv c3743e7b62a799700b926af3015aa656
author_id_fullname_str_mv c3743e7b62a799700b926af3015aa656_***_ALEXANDER BEDFORD
author ALEXANDER BEDFORD
author2 ALEXANDER BEDFORD
format E-Thesis
publishDate 2025
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Biosciences{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Biosciences
document_store_str 1
active_str 0
description This study reports on the prevalence, intensity, and species identification of digenean trematode infections in shore crabs (Carcinus maenas) found at two intertidal survey sites (Mumbles Head and Oxwich Bay) in the Bristol Channel, U.K. between February, and August 2024. Crabs were assessed for the presence and intensity of trematode infections by the microscopic examination of the hepatopancreas. The metacercariae species identification resulted from the combined use of morphological and PCR-based methods, specifically the 28S rDNA gene. Encysted metacercariae presented in two distinct forms, spherical and asymmetrical, which were shown to be Microphallus similis and M. primas, respectively. A high prevalence and intensity of M. similis metacercariae was found in shore crab populations from both locations throughout the duration of the study. Conversely, M. primas metacercariae were only identified in a limited number of crabs and at low infection intensities during June and August sampling. No cellular host immune responses were observed.Binomial logistic regression models revealed size and colouration to be significant factors in trematode presence at Oxwich Bay only. Additionally, larger/older shore crabs were found to harbour more metacercarial cysts, with larger metacercariae observed in crabs from Mumbles Head. Overall, the findings of this study highlight the widespread prevalence of M. similis infections in shore crab populations at both intertidal survey sites, with notable size and location-specific variations in infection intensity. Additionally, the results underscore the importance of conducting a long-term study to better understand the seasonal dynamics of M. similis and M. primas infections in shore crabs.
published_date 2025-05-12T05:29:48Z
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score 11.09611

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