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Nagasawa K. Live Freshwater Parasite, Salmincola californiensis (Copepoda: Lernaeopodidae), on the Gills of an Ocean-Migrating Steelhead Trout ( Oncorhynchus mykiss) and Discussion on the Origin and Survival of the Parasite at Sea. Zoolog Sci 2023; 40:360-366. [PMID: 37818884 DOI: 10.2108/zs230031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 06/23/2023] [Indexed: 10/13/2023]
Abstract
Salmincola californiensis is a parasitic copepod of freshwater salmonids in the North Pacific rim countries. Sixteen adult females of the species were found alive on the gills of an ocean-age 4, maturing steelhead trout, Oncorhynchus mykiss, caught in offshore waters (50°30'N, 179°30'W) of the North Pacific Ocean in July 1997. This is the first evidence of live individuals of S. californiensis from ocean-migrating salmonids. When found, copepods were attached to the distal ends of gill filaments, and their bodies were observed to be slowly moving in Petri dishes with seawater. Ocean-migrating steelhead trout comprise individuals originating from western Kamchatka (Russia) and western North America. Based on the date and catch location of the infected fish, it is inferred that it originated from western North America, where it acquired S. californiensis infection in fresh water. As this fish spent about 4 years in the ocean, the copepods likely survived the same period at sea. However, if the fish was a kelt, the survival period of the copepods in the ocean may be shorter than four years. To confirm identification of the copepods, adult females of S. californiensis are briefly described using the specimens collected from the fish.
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Affiliation(s)
- Kazuya Nagasawa
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8528, Japan,
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Henriksen EH, Frainer A, Poulin R, Knudsen R, Amundsen P. Ectoparasites population dynamics are affected by host body size but not host density or water temperature in a 32‐year long time series. OIKOS 2022. [DOI: 10.1111/oik.09328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Eirik H. Henriksen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - André Frainer
- Norwegian Inst. for Nature Research (NINA), Framsenteret Tromsø Norway
| | | | - Rune Knudsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Per‐Arne Amundsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
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Lepak JM, Hansen AG, Hooten MB, Brauch D, Vigil EM. Rapid proliferation of the parasitic copepod, Salmincola californiensis (Dana), on kokanee salmon, Oncorhynchus nerka (Walbaum), in a large Colorado reservoir. JOURNAL OF FISH DISEASES 2022; 45:89-98. [PMID: 34585403 DOI: 10.1111/jfd.13539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/05/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
Ecologically and economically valuable Pacific salmon and trout (Oncorhynchus spp.) are widespread and susceptible to the ectoparasite Salmincola californiensis (Dana). The range of this freshwater copepod has expanded, and in 2015, S. californiensis was observed in Blue Mesa Reservoir, Colorado, USA, an important kokanee salmon (O. nerka, Walbaum) egg source for sustaining fisheries. Few S. californiensis were detected on kokanee salmon in 2016 (<10% prevalence; 2 adult S. californiensis maximum). By 2020, age-3 kokanee salmon had 100% S. californiensis prevalence and mean intensity exceeding 50 adult copepods. Year and kokanee salmon age/maturity (older/mature) were consistently identified as significant predictors of S. californiensis prevalence/intensity. There was evidence that S. californiensis spread rapidly, but their population growth was maximized at the initiation (the first 2-3 years) of the invasion. Gills and heads of kokanee salmon carried the highest S. californiensis loads. S. californiensis population growth appears to be slowing, but S. californiensis expansion occurred concomitant with myriad environmental/biological factors. These factors and inherent variance in S. californiensis count data may have obscured patterns that continued monitoring of parasite-host dynamics, when S. californiensis abundance is more stable, might reveal. The rapid proliferation of S. californiensis indicates that in 5 years a system can go from a light infestation to supporting hosts carrying hundreds of parasites, and concern remains about the sustainability of this kokanee salmon population.
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Affiliation(s)
- Jesse M Lepak
- Colorado Parks and Wildlife, Aquatic Research Section, Fort Collins, Colorado, USA
| | - Adam G Hansen
- Colorado Parks and Wildlife, Aquatic Research Section, Fort Collins, Colorado, USA
| | - Mevin B Hooten
- Department of Statistics and Data Sciences, The University of Texas at Austin, Austin, Texas, USA
| | - Daniel Brauch
- Colorado Parks and Wildlife, Gunnison, Colorado, USA
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Hasegawa R, Ayer CG, Umatani Y, Miura K, Ukumura M, Katahira H, Koizumi I. Potential negative effects and heterogeneous distribution of a parasitic copepod Salmincola edwardsii (Copepoda: Lernaeopodidae) on Southern Asian Dolly Varden Salvelinus curilus in Hokkaido, Japan. Parasitol Int 2021; 87:102529. [PMID: 34896616 DOI: 10.1016/j.parint.2021.102529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 08/19/2021] [Accepted: 12/06/2021] [Indexed: 11/25/2022]
Abstract
The genus Salmincola is an ectoparasitic copepod group commonly infesting the branchial and buccal cavities of salmonids. While negative impacts on hatchery fishes have been reported, their impacts on wild fish populations and distribution patterns are critically understudied. In the Shiretoko Peninsula, Hokkaido, Japan, we found parasites belonging to this genus on the branchial cavity of a stream salmonid, Southern Asian Dolly Varden Salvelinus curilus. All parasites recovered were identified as Salmincola edwardsii based on morphological characteristics and partial 28S rDNA sequences. Prevalence was highly heterogeneous even among neighboring streams (0-54.8%, < 10 km) with the mean intensity among streams being generally low (2.19 parasites/infeted fish). Despite the low intensity, quantile regression analysis showed negative trends between parasite intensity and host condition, suggesting that the infestation of S. edwardsii has a potential negative impact on the host salmonid. In addition, a single copepod was found from an anadromous fish, which could indicate some salinity tolerance of the copepods. It is important to evaluate the effects of Salmincola spp. on host species and determine the limiting factors on the parasite's distribution for proper management.
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Affiliation(s)
- Ryota Hasegawa
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.
| | - Christopher G Ayer
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Yoshiyuki Umatani
- Field Science Center for Northern Biosphere, Hokkaido University, Sapporo, Hokkaido 060-0809, Japan
| | - Kazuki Miura
- Shiretoko Museum, Honmachi 49, Shari, Shari-gun, Hokkaido 099-4113, Japan
| | - Miyo Ukumura
- Sapporo Wild Salmon Project, 2-1 Makomanai Park, Minami-ku, Sapporo, Hokkaido 005-0017, Japan
| | - Hirotaka Katahira
- Department of Environmental Science, School of Life and Environmental Science, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan
| | - Itsuro Koizumi
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan; Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
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Hasegawa R, Koizumi I. Relative importance of host‐dependent versus physical environmental characteristics affecting the distribution of an ectoparasitic copepod infecting the mouth cavity of stream salmonid. Ecol Res 2021. [DOI: 10.1111/1440-1703.12262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryota Hasegawa
- Graduate School of Environmental Science Hokkaido University Sapporo Japan
| | - Itsuro Koizumi
- Graduate School of Environmental Science Hokkaido University Sapporo Japan
- Faculty of Environmental Earth Science Hokkaido University Sapporo Japan
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Neal T, Kent ML, Sanders J, Schreck CB, Peterson JT. Laboratory infection rates and associated mortality of juvenile Chinook Salmon (Oncorhynchus tshawytscha) from parasitic copepod (Salmincola californiensis). JOURNAL OF FISH DISEASES 2021; 44:1423-1434. [PMID: 34053103 DOI: 10.1111/jfd.13450] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
Pacific salmon (Oncorhynchus spp.) rearing in lakes and reservoirs above dams have been known to become heavily infected with an ectoparasitic copepod (Salmincola californiensis). Little is known about the factors that affect the parasite infection prevalence and intensity. However, previous research suggests that the parasite may negatively affect the fitness and survival of the host fish. The effect of water temperature, confinement and the density of the free-swimming infectious stage of S. californiensis, the copepodid, on infection prevalence and intensity was evaluated by experimentally exposing juvenile Chinook Salmon (O. tshawytscha). Infection rates observed in wild populations were achieved under warm water (15-16°C) and high copepodid density (150-300/L) treatment conditions. Infection prevalence and intensity were also significantly higher in larger fish. During the infection experiment, 4.5% of infected fish died within 54 days with mortality significantly related to copepod infection intensity. The potential for autoinfection was compared to cross-infection by cohabitation of infected fish with naïve fish. Previously infected fish had significantly greater infection intensity compared with naïve fish, indicating that infected fish can be reinfected and that they may be more susceptible than naïve fish.
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Affiliation(s)
- Travis Neal
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA
| | - Michael L Kent
- Department of Microbiology, Oregon State University, Corvallis, OR, USA
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR, USA
| | - Justin Sanders
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR, USA
| | - Carl B Schreck
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA
| | - James T Peterson
- US Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA
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Hatching and survival of the salmon 'gill maggot' Salmincola californiensis (Copepoda: Lernaeopodidae) reveals thermal dependence and undocumented naupliar stage. Parasitology 2020; 147:1338-1343. [PMID: 32660654 DOI: 10.1017/s0031182020001109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Salmincola californiensis is a Lernaeopodid copepod parasitizing Pacific salmon and trout of the genus Oncorhynchus. Salmincola californiensis is of increasing concern in both native and introduced ranges because of its potential fish health impacts and high infection prevalence and intensity in some systems. Discrepancies in the documented life history phenology of S. californiensis with the sister species Salmincola edwardsii, as well as our laboratory observations, led us to question the existing literature. We documented a naupliar stage, thought lost for S. californiensis. In addition, we found a high degree of thermal sensitivity in egg development, with eggs developing faster under warmer conditions. Survival of copepodids was also highly dependent on temperature, with warmer conditions reducing lifespan. The longest lived copepodid survived 18 days at 4°C in stark contrast to the generally accepted <48 h survival for that life stage. We also note a consistent relationship between egg sac size and the number of eggs contained. However, egg sac sizes were highly variable. Our findings demonstrate that revisiting old assumptions for S. californiensis and related taxa will be a necessary step to improving our knowledge of the parasite life history and development that will be critical to disease management.
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White CFH, Gray MA, Kidd KA, Duffy MS, Lento J, Monk WA. Prevalence and Intensity of Salmincola edwardsii in Brook Trout in Northwest New Brunswick, Canada. JOURNAL OF AQUATIC ANIMAL HEALTH 2020; 32:11-20. [PMID: 31965614 DOI: 10.1002/aah.10091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
Parasites can compromise the health and fitness of individual fish, and it is important to generate baseline information that can then be used to document changes in the abundance and distribution of potentially pathogenic parasites. The ectoparasitic copepod Salmincola edwardsii was assessed with respect to prevalence (percentage of infected fish per site), infection intensity (number of parasites per infected fish), and attachment location on Brook Trout Salvelinus fontinalis in northwest New Brunswick, Canada. Ten sample sites were assessed, with six sites on two streams in the Quisibis River basin and four sites on three streams in the Restigouche River basin. Parasite species identity was supported by 100% sequence identity with S. edwardsii in a variable region within 28S rDNA. The prevalence of fish infected per site ranged from 19.0% to 79.6%, with an overall prevalence of 48.5 ± 19.1% (mean ± SD) per site. Mean infection intensity was 1.5 ± 0.9 copepods/fish (range = 1-7), with parasites almost exclusively surrounding the dorsal fin and/or adipose fin (97.6%). There was no influence of trout age-class on parasite prevalence. Some fish presented with fin erosion at the site of parasite attachment (12.5%), and 6.2% also presented with hyperplastic skin lesions where no parasites were observed, that could be misinterpreted as secondary bacterial or fungal infections. Skin and fin damage were significantly more common when fish were infected with three or more individual parasites. The pathogenic potential of this parasite makes its presence noteworthy as a risk to salmonids that are both recreationally and ecologically important.
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Affiliation(s)
- Carson F H White
- Canadian Rivers Institute, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
- Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - Michelle A Gray
- Canadian Rivers Institute, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
- Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - Karen A Kidd
- Department of Biology and School of Geography and Earth Sciences, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
- Canadian Rivers Institute, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada
| | - Michael S Duffy
- Canadian Rivers Institute, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - Jennifer Lento
- Canadian Rivers Institute, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - Wendy A Monk
- Environment and Climate Change Canada at Canadian Rivers Institute, Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
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Mitro MG, Griffin JD. Distribution, Prevalence, and Maximum Intensity of the Ectoparasitic Copepod Salmincola cf. Edwardsii in Brook Trout in Wisconsin Streams. J Parasitol 2018; 104:628-638. [PMID: 30138083 DOI: 10.1645/17-146] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Since the late 19th century, the ectoparasitic copepod Salmincola cf. edwardsii has been observed infecting brook trout ( Salvelinus fontinalis) in Wisconsin streams. A perceived increase in the incidence of S. cf. edwardsii infection across the state and the observation of an S. edwardsii epizootic leading to declines in brook trout recruitment in Ash Creek, Wisconsin, have raised concerns about the extent to which S. edwardsii threaten other populations of brook trout in Wisconsin streams. In 2013-2017, brook trout were inspected in 282 streams across the state to determine the distribution, prevalence, and maximum intensity of infection of adult female copepods whose morphology was consistent with S. edwardsii. Salmincola cf. edwardsii were present in 79% of streams and absent from 21%. Prevalence of infection ranged from 0.4 to 100% where the parasite was present. Maximum intensity of infection was low (1-5 S. cf. edwardsii) in 31% of streams, moderate (6-14) in 35% of the streams, and high (≥15) in 34% of the streams. Maximum intensity was high and prevalence exceeded 90% of brook trout in 9 streams, suggesting epizootics as observed in Ash Creek are uncommon. Our statewide distributional data are critical to understanding the scope of S. cf. edwardsii infection of brook trout in Wisconsin's recreational fisheries and will provide a baseline for ongoing and future investigations of S. cf. edwardsii-brook trout dynamics.
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Affiliation(s)
- Matthew G Mitro
- 1 Wisconsin Department of Natural Resources, Office of Applied Science, Division of Fish, Wildlife and Parks, Science Operations Center, 2801 Progress Road, Madison, Wisconsin 53716
| | - Joanna D Griffin
- 2 Wisconsin Department of Natural Resources, Fisheries Management Bureau, Division of Fish, Wildlife and Parks, 101 S. Webster Street, Madison, Wisconsin 53707
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Herron CL, Kent ML, Schreck CB. Swimming Endurance in Juvenile Chinook Salmon Infected with Salmincola californiensis. JOURNAL OF AQUATIC ANIMAL HEALTH 2018; 30:81-89. [PMID: 29595884 DOI: 10.1002/aah.10010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 12/15/2017] [Indexed: 06/08/2023]
Abstract
Juvenile Chinook Salmon Oncorhynchus tshawytscha moving downstream through tributaries of the upper Willamette River basin can spend months in reservoirs created by dams. While residing in the reservoirs, they often obtain heavy infections of the freshwater parasitic copepod Salmincola californiensis. The physiologic effect these parasites have on salmonids is poorly understood. We developed a method to infect juvenile Chinook Salmon in a laboratory with the copepodid stage of S. californiensis. Infected and uninfected fish were subjected to a swimming challenge to ascertain swimming endurance. Severity of gill damage was assessed using a dissecting microscope. Juvenile Chinook Salmon naturally infected with S. californiensis in Cougar Reservoir, Oregon, were also challenged and compared with their lab-infected counterparts. Copepod infection greatly impaired the swimming ability of laboratory fish, and the naturally infected fish were entirely incapable of swimming at low velocity. Chinook Salmon collected in the wild were more heavily infected than the laboratory fish and had trouble surviving collection and transport to our laboratory. The intensity of infection and severity of gill damage were positively correlated with diminished swimming ability, suggesting that heavy infection with copepods impairs gas exchange and osmotic regulation, which likely results in diminished fitness and decreased survival of infected fish.
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Affiliation(s)
- Crystal L Herron
- Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, Oregon, 97331, USA
| | - M L Kent
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, Oregon, 97331, USA
| | - C B Schreck
- Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, Oregon, 97331, USA
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