Parasitic Copepod Research Articles

Low‐level infection of parasitic copepods on Rainbow Trout does not affect vulnerability to angling or short‐term survival following catch‐and‐release angling

AbstractObjectiveParasitic copepods, or “gill lice,” can harm fish hosts, resulting in reductions in fitness and increased probability of mortality. The purpose of our study was to determine the effect of Salmincola californiensis on the vulnerability of Rainbow Trout Oncorhynchus mykiss to recreational angling and short‐term survival after being caught and released.MethodsWe compared the prevalence and intensity of infection of S. californiensis on Rainbow Trout that were caught while angling and with a backpack electrofisher in May and October 2020 in Birch Creek, Idaho. In October, we also conducted a stress test (air‐exposure treatment) on trout that were caught by angling to determine the effects of parasitic copepods on the short‐term survival of Rainbow Trout in a catch‐and‐release fishery.ResultInfection with S. californiensis did not influence the vulnerability of Rainbow Trout to angling. After adjusting for sample size and size distribution, the prevalence of infection in May was 48.3% for Rainbow Trout that were caught while electrofishing and 49.3% for Rainbow Trout that were caught while angling. In October, the prevalence of infection was 41.2% for Rainbow Trout that were caught while electrofishing and 41.8% for Rainbow Trout that were caught while angling. We did not find a difference in short‐term survival rates for infected and uninfected Rainbow Trout after the stress test (4–7 days after the test).ConclusionWe did not observe consequences of infection by parasitic copepods on vulnerability to angling or short‐term survival of Rainbow Trout in Birch Creek. However, the conditions (low‐level of infection and relatively small fish) may not have been conducive to detecting differences in the performance metrics; further testing at higher intensity of infection and with larger fish may uncover the negative effects of parasitic copepods on Rainbow Trout.

Validity of Visible Ectoparasite Intensity As a Non-invasive Biomarker for Fish welfare: Parasitic Copepod, Lernantropus kroyeri in Sea Bass As an Example

Validity of Visible Ectoparasite Intensity As a Non-invasive Biomarker for Fish welfare: Parasitic Copepod, Lernantropus kroyeri in Sea Bass As an Example

Aeromonas salmonicida, causative agent of salmonid furunculosis, isolated from the freshwater parasitic copepod, Salmincola californiensis.

Here, we provide evidence that the freshwater parasitic copepod, Salmincola californiensis, acts as a vector for Aeromonas salmonicida. While investigating the effects of S. californiensis on Chinoook salmon (Oncorhynchus tshawytscha), we tangentially observed that fish infected with the copepod developed furunculosis, caused by A. salmonicida. This occurred despite being reared in pathogen-free well water in a research facility with no prior history of spontaneous infection. We further investigated the possibility of S. californiensis to serve as a vector for the bacterium via detection of fluorescently labelled A. salmonicida inside the egg sacs from copepods in which the fish hosts were experimentally infected with GFP-A449 A. salmonicida. We then evaluated copepod egg sacs that were collected from adult Chinook salmon from a freshwater hatchery with A. salmonicida infections confirmed by either culture or PCR. The bacterium was cultured on tryptic soy agar plates from 75% of the egg sacs, and 61% were positive by PCR. These three separate experiments indicate an alternative tactic of transmission in addition to direct transmission of A. salmonicida in captivity. The copepod may play an important role in transmission of the bacterium when fish are more dispersed, such as in the wild.

A new species of Cardiodectes Wilson C.B., 1917 (Copepoda: Siphonostomatoida: Pennellidae) from Spinyjaw greeneye, Chlorophthalmus corniger Alcock, 1894 off the Indian Ocean.

A new species of flesh penetrating parasitic copepod of the genus CardiodectesWilson C.B., 1917 (Siphonostomatoida: Pennellidae) parasitizing the fish Spinyjaw greeneye, Chlorophthalmus cornigerAlcock, 1894 (Chlorophthalmidae), inhabiting at depths of 265 to 458 meters from the south-west coast of India is described and illustrated. The new species, Cardiodectes vampire sp. nov., can be distinguished from its other 16 congeners by the following features: (i) trunk 3.15 times as long as wide; (ii) extremely long (3.5 times as long as total body length) and uncoiled egg sacs; (iii) difference in the armature of legs 13; (iv) comparatively longer trunk (0.7 times as long as total body length). A checklist of valid global species of Cardiodecteswith its host and distribution is also provided.

OCCURRENCE OF Tuxophorus caligodes WILSON, 1908 (COPEPODA: CALIGIDAE) A PARASITE OF Echeneis naucrates LINNAEUS, 1758 (ACTINOPTERYGII: ECHENEIDAE) OFF THE BRAZILIAN AMAZON COAST

In this paper the first record of Tuxophorus caligodes Wilson, 1908 (Siphonostomatoida: Caligidae) off the North coast of Brazil is documented. This caligid copepod was found parasitizing the live sharksucker Echeneis naucrates Linnaeus, 1758 (Carangiformes: Echeneidae) a typical host of this parasitic copepod in the Atlantic waters.

DNA Identification of Parasitic Copepods <i>Salmincola</i> (Copepoda, Siphonostomatoida, Lernaeopodidae): Variability and Rate of Evolution of the Mitochondrial Cytochrome c Oxidase Subunit I Gene

The barcode fragment of the COI gene was sequenced in 91 specimens of five species of parasitic Salmincola copepods, sampled from salmonids mainly from the Russian Far East: S. californiensis (mykiss and masu salmon) and S. edwardsii (various species of chars, sockeye salmon from Lake Kronotskoe), S. carpionis (various species of chars), S. markewitschi (whitespotted char), S. stellata (Sakhalin taimen). A total of 41 haplotypes were found with a maximum level of differences of 0.183 nucleotide substitutions per position. The distance between species varied from 0.139 ± 0.014 in the S. markewitschi–S. carpionis pair to 0.179 ± 0.015 in the S. stellata–S. californiensis pair. The intraspecific nucleotide diversity of the COI gene fragment is much lower: for S. californiensis and S. edwardsii, inhabiting the gill cavity and fins of the host – 0.013 ± 0.003 and 0.015 ± 0.003, and for S. stellata, S. markewitschi, and S. carpionis, localized in the buccal cavity of the hosts – 0.002 ± 0.001, 0.004 ± 0.001, and 0.005 ± 0.001, respectively. A comparison of samples of three Salmincola copepod species from different regions of the Russian Far East revealed a significant (Fst = 0.28–0.42, P \( \ll \) 0.001) genetic subdivision. Three subclades of edwardsii-like copepods – S. edwardsii from the Russian Far East, S. edwardsii from the American brook char of eastern North America, and S. siscowet from the lake char of Michigan (COI sequences of copepods from the last two groups are taken from genetic databases) – differed from each other by an average of 9.3–10.9% nucleotide positions, which means the need for a taxonomic revision of S. edwardsii. According to the molecular dating carried out, the divergence of Salmincola lineages started in the Miocene and ended in the early Pliocene. The phylogenetic substitution rate was 0.0228 (95% interval: 0.0132–0.033) nucleotide substitutions/position/million years/lineage. The rate of nucleotide substitutions at the population level is 3.7 times higher – 0.0849 (0.0212–0.170). The high level of variability of the COI gene fragment makes this marker a useful tool both for developing the taxonomy and phylogeny of Salmincola and Lernaeopodidae copepods at the species and genus levels, and for analyzing the differentiation of their populations.

DNA Identification of Parasitic Copepods Salmincola (Copepoda, Siphonostomatoida, Lernaeopodidae): Variability and Rate of Evolution of the Mitochondrial Cytochrome c Oxidase Subunit I Gene

DNA Identification of Parasitic Copepods Salmincola (Copepoda, Siphonostomatoida, Lernaeopodidae): Variability and Rate of Evolution of the Mitochondrial Cytochrome c Oxidase Subunit I Gene

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.

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.

Population and Transcriptomic Changes of the Tropical Fish Parasite Caligus confusus (Copepoda: Caligidae) with Seasonal Variations in Sea Temperature

Fish–parasite systems could be subject to two scenarios under climate change: (i) increased water temperature might enhance parasite metabolism, allowing the parasite to spread rapidly; (ii) parasitism could decrease if the optimal temperature for growth and transmission is exceeded. Sea lice are parasitic copepods commonly found on marine fish in tropical regions, yet their biology remains poorly investigated. In this study, we analyzed the changes in infection levels and the transcriptomic response of the tropical sea louse Caligus confusus to two seasonal seawater temperatures (30 °C, “warm”, and 21 °C, “cold”). The prevalence of C. confusus was significantly higher in the colder water. A de novo transcriptomic analysis of C. confusus, the first for a tropical sea louse, revealed 426 over-expressed and 1402 down-expressed transcripts at the lower temperature. In particular, we observed over-expression of transcripts encoding vitellogenins (vit-1, vit-2, vit-4, and vit-6) and matrix metalloproteinases (mmp-2 and mmp-9), which are involved in reproduction and development. These results suggest that the cold tropical season physiologically favors C. confusus and that low temperature favors embryo development, which might ultimately lead to a higher prevalence. It is possible, therefore, that climate change could reduce some tropical sea lice populations during extreme warming events.

How many species of genus Lernaeopoda Blainville, 1822 (Siphonostomatoida: Lernaeopodidae) are there in the southwestern Atlantic?

The family Lernaeopodidae includes 14 genera parasitizing elasmobranchs. Fourteen species of this family have been cited from Argentina, four of which were found on chondrichthyans. Schroederichthys bivius Mller and Henle and Galeorhinus galeus (Linnaeus) from Argentina harbored parasitic copepods of the genus Lernaeopoda. The objective of this study was to identify the species using an integrative approach. The morphology was examined by Optical Microscopy and Scanning Electron Microscopy and the molecular analysis was based on partial sequences of the COI mtDNA gene. Despite differences in the antenna, antennule, mandible, maxilliped and maxillae among the specimens, the morphological and molecular analyses revealed that they belonged to Lernaeopoda bivia Leigh-Sharpe, 1930. The species so far reported for Argentina are L. bivia and L. galei Kryer, 1837, which are distinguished by the size (less and greater than 7 mm, respectively). Here, we report partial sequences of the COI mtDNA gene of L. bivia for the first time, obtained from eleven specimens attached to the mouth, fins, anal slit and claspers of the two shark hosts. The COI mtDNA gene tree shows that the Lernaeopoda group forms a sister clade with Pseudocharopinus bicaudatus (Kryer, 1837), while the genus Pseudocharopinus does not appear to be a natural group. We propose that the material described from Argentinean waters as L. galei was misidentified and actually belongs to L. bivia. The wide variability within the specimens of L. bivia emphasizes the importance of using an integrative approach to revise the taxonomy of the Lernaeopoda species from all over the world.

Ultrastructural observation on the parasitic copepod, Lamproglena monodi Capart, 1944, infesting the gills of Sarotherodon galilaeus caught from the River Nile and Lake Manzala, Egypt, using the parasite as a bioindicator for pollution

Ultrastructural observation on the parasitic copepod, Lamproglena monodi Capart, 1944, infesting the gills of Sarotherodon galilaeus caught from the River Nile and Lake Manzala, Egypt, using the parasite as a bioindicator for pollution

CHOROLOGIC ANALYSIS OF THE MARINE COPEPODS (COPEPODA) PARASITIC ON FISHES OF VIETMAM

Nowadays 72 species of copepods (Copepoda) parasitizing marine fish in Vietnam have been identified. The chorological analysis of marine parasitic copepods allows to distinguish nine groups of species: widespread Atlantic-Pacific (23 species), Indo-West- Pacific (without Oceania) (25 species), Indo-West-Pacific with a broken range (11 species), Western Pacific (including Oceania) (1 species), Japanese-Malay (2 species), Philippine- Malay (1 species), Chinese-Australian (1 species), Chinese-Japanese (4 species) and endemics of Vietnam (4 species). The majority of Vietnamese marine copepods belong to the Indo-West- Pacific (34.7% species), and widespread Atlantic-Pacific groups (34.7% and 31.9% species, respectively). A preliminary comparison of the species composition of copepods from Japan, Taiwan, the Philippines, and Vietnam was made. Keywords: marine copepods, distribution, South

Integrative Morphological and Genetic Characterisation of the Fish Parasitic Copepod Ergasilus mirabilis Oldewage & van As, 1987: Insights into Host Specificity and Distribution in Southern Africa

Ergasilids are external parasites typically found on the gills and fins of their hosts. In Africa, 19 species of Ergasilus von Nordmann, 1832 are reported. Of those, Ergasilus mirabilis Oldewage & van As, 1987 is one of the least host-specific, with a wide distribution range in southern Africa. As with most species in the genus, genetic data are not available to support the morphological placement of this species within the genus. Specimens representing E. mirabilis were obtained from the gills of Clarias gariepinus (Burchell, 1822) collected from several localities in South Africa and Zambia. Fish were dissected and gills screened using standard techniques. Following a comprehensive morphological study using light and scanning electron microscopy, additional morphological characters are reported. Furthermore, novel data on partial 18S, 28S (rRNA), and COI (mtDNA) gene regions are presented. This is the first integrative study on the morphology of E. mirabilis with supporting genetic data, as well as new distribution records from the KuShokwe Pan in the Phongolo River floodplain and the Vaal River in South Africa, and from the Barotse floodplain in Zambezi River, Zambia. An updated overview is provided for the species of Ergasilus from Africa, including hosts, distribution, and genetic information.

Correlation of endemicity between monogenean trematode, Microcotyle sebastis, and parasitic copepods in Korean rockfish, Sebastes schlegelii, from a fish farm in Tongyeong-si, Gyeongsangnam-do, Korea.

Infestations of parasites, particularly those caused by copepods and monogeneans, are a major hindrance to aquaculture and have a big negative economic impact. Sebastes schlegelii, a farmed Korean rockfish, is particularly prone to copepods and monogeneans. This study comprehended how parasitic copepods and rockfish from a farm in Tongyeong-si, Gyeongsangnam-do, Korea, are related to the monogenean trematode Microcotyle sebastis. Our research revealed that monogeneans predominated, with a rate of 98.4% and an average infection intensity of 7 per infected fish. With an average infection intensity of 4 per sick fish, the infection rate for parasitic copepods was equally considerable, coming in at 91.7%. The high co-infection rate of both parasite families, at 90.8%, is noteworthy. Furthermore, Lepeophtheirus elegans and Peniculus truncatus, 2 parasitic copepod species, were discovered to have M. sebastis eggs attached to their bodies. This demonstrates a connection between parasitic copepod infestations in farmed Korean rockfish and the monogenean trematode M. sebastis. These discoveries highlight the necessity for creating more potent parasite control methods for the aquaculture sector and shed light on the intricate relationships between various parasite species.

Silencing of the Vasa gene by RNA Interference Affects Embryonic Development and Reproductive Output in the Sea Louse Caligus rogercresseyi.

The sea louse Caligus rogercresseyi is a major ectoparasitic copepod that causes significant economic losses in the salmon farming industry. Despite recent advancements, the mechanisms underlying germline and embryo development in this species remain poorly understood. The Vasa gene encodes a highly conserved DEAD box helicase that is required for germ cell formation and function in many species. In this study, the Vasa gene was characterized in C. rogercresseyi, and its expression and function were analyzed. Phylogenetic analysis showed that the Cr-Vasa gene product formed clusters in clades with Vasa proteins from closely related species of crustaceans. Cr-Vasa gene expression patterns were assessed by qPCR, and the results showed a significantly higher relative expression level in adult females compared to copepodid, chalimus, and adult male stages. Tissue-specific localization of Cr-Vasa mRNA in C. rogercresseyi was determined using chromogenic in situ hybridization, and strong positive signal was observed in male testes, but also in the intestine and cuticle, while in females, it was observed in the ovaries, oocytes, cuticle, intestine, and egg strings. RNAi-mediated gene silencing of Cr-Vasa impacted embryonic development and reproductive output in adult female lice. Females from the dsVasa-treated group displayed unusual phenotypes, including shorter egg strings with numerous extra-embryonic inclusions, irregularly shaped abnormal embryos, and aborted egg strings. This study provides insights into the role of the Vasa gene in C. rogercresseyi embryonic development and reproductive output, which may have implications for the control of this parasitic copepod in the salmon farming industry.

Scanning Electron Microscopy and First Molecular Data of Two Species of Lamproglena (Copepoda: Lernaeidae) from Labeo victorianus (Cyprinidae) and Clarias gariepinus (Clariidae) in Kenya.

A parasitological study carried out in May 2022 and March 2023 in the Nyando River of Lake Victoria Basin, Kenya, disclosed two parasitic lernaeid copepods: Lamproglena cleopatra Humes, 1957, from the gills of a cyprinid, the Ningu Labeo victorianus Boulenger, 1901, endemic to the Lake Victoria drainage system, and Lamproglena clariae Fryer, 1957, from a clariid, the North African catfish Clarias gariepinus (Burchell, 1822). The copepods were studied and supplementary taxonomic information was presented using scanning electron micrographs and genetic data. Scanning electron microscopy (SEM) provided information on the morphology of L. cleopatra's antennae, oral region, thoracic legs (2-5), and furcal rami not previously reported. Analyses of the partial fragments of 18S and 28S rDNA and cytochrome c oxidase subunit 1 (cox1) of the two parasites showed them to be distinct from all other Lamproglena taxa retrieved from GenBank. This study presents new taxonomic information on morphology using SEM and provides the first ribosomal (18S and 28S rDNA) and mitochondrial (mtDNA) data for these two parasite species. The cox1 data provided are the first for all 38 nominal species of Lamproglena. Notably, the study also provides a new host record for L. cleopatra and extends the geographical information of this species to Kenya.

Haematological alterations of mullet Planiliza abu (Heckel, 1843) naturally infected by Ergasilus mosulensis Rahemo, 1982 (Copepoda: Ergaslidae) in a private fish farm from Basrah Province, Iraq

Generally, there is no previous information about haematological parameters of parasitized fish maintained in fish farms in Al- Mashab area, Basrah, Iraq. In this study, the effects of parasitism by the copepod Ergasilus mosulensis. on haemoglobin (Hb), haematocrit (HCT), red blood cells (RBCS), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and leucocytes were analysed in infected Planiliza abu. The high level of parasitism found in infected fishes was responsible for alterations in blood picture Hb, HCT, RBCS, MCV, MCH, MCHC, and leucocytes (P > 0.05). This is the first report regarding hematology of cultivated freshwater fish which are infected with parasitic copepods in Basrah Province.

Distribution of some parasitic copepods on Actinopterygii fish from Egyptian water of Alexandria coast, with referencing to the histopathological alteration

Distribution of some parasitic copepods on Actinopterygii fish from Egyptian water of Alexandria coast, with referencing to the histopathological alteration

HALALAN TAYYIBAN IN AQUACULTURE PRACTICE – A CASE STUDY ON PARASITE IN HATCHERY


 
 
 
 Halal is an important issue in aquaculture since this industry produces food for human consumption. This paper aimed to discuss the procedures and practices in the current aquaculture in relation to the concept of halal as a subject while tayyib is a process where clean and pure food will be produced and gives comfort to the user or consumer, thus the product is recognized and certified as Halala Tayyiba. Fish brood stock obtained from a river and kept under a hatchery condition was assigned for the case study. The ectoparasite species found on Tilapia under hatchery cultured condition was investigated. The weight and total length of the Tilapia were measured, and mucus coating was swapped to 10% buffered formalin using the scraping technique. The morphology of copepod parasites was observed under a compound microscope for identification. Hosts with infection of ectoparasite showed reduced weight and increased mortality. A comprehensive understanding of the importance of adopting Halala Tayyiba principles in aquaculture procedures will improve the aquaculture product thus bringing forward local farmers in the halal supply chain. 
 
 
 

What causes transformation of the parasitic copepod? A new example of host switching in the family Anthessiidae (Cyclopoida) from Singaporean waters, with the proposal of a new genus

Abstract Merlionia zeeae , a new species belonging to a new genus, is described as a member of the cyclopoid family Anthessiidae (Copepoda), based on both sexes collected off the coast of Singapore. The new species was found in the gill cavities of the longnosed stargazer, Ichthyscopus lebeck (Actinopteri: Perciformes: Uranoscopidae), although almost all members of the family are associated with molluscan hosts. However, this copepod is not similar to other genera of the family Anthessiidae due to possessing the following characters: the curved hook-like antenna, which is similar to that of the family Chondracanthidae in both sexes; the distal portion of the maxilla covered with numerous spinules; and the lack of the maxilliped in the female. Both maximum likelihood and Bayesian inferences using partial SSU (18S) ribosomal RNA genes strongly supported a monophyletic clade formed by the new genus, and three anthessiid genera in this study. However, it was not supported that Anthessiidae and Chondracanthidae are closely related. Therefore, the new genus is considered to be a highly transformed member of the former, and the chondracanthid-form antenna might therefore be a product of convergent evolution attributable to the host-switching event from molluscs to fishes.