Hubbry Logo
ArgulusArgulusMain
Open search
Argulus
Community hub
Argulus
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Argulus
Argulus
Argulus
View on Wikipedia
from Wikipedia

Argulus
Argulus coregoni
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Ichthyostraca
Subclass: Branchiura
Order: Arguloida
Family: Argulidae
Genus: Argulus
Müller, 1785
Species

~140 species (see list)

Argulus is a genus of fish lice in the family Argulidae. There are about 140 accepted species in the genus Argulus.[1][2][3][4] They occur in marine, brackish, and freshwater environments.[1] They sit tightly against the host body,[5] this minimises risk of detachment. As juveniles, these species feed on mucous and skin cells of their host. With age they become blood feeders because the parasite moves from feeding on the fins to feeding on the body of the fish, causing the feeding change.[6] At least some species can have severe impacts on their host populations.[5]

Argulus japonicus

Taxonomy

[edit]

As of December 2022, 138 species are accepted: List of Argulidae species[1]

References

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Argulus

View on Grokipedia
from Grokipedia
Argulus is a of ectoparasitic crustaceans commonly known as lice, belonging to the Argulidae within the subclass Branchiura. These dorsoventrally flattened organisms, typically measuring 3–20 mm in length, attach to the external surfaces of hosts—such as the skin, fins, and gills—using paired sucker-like first maxillae and numerous spines on their ventral side for anchorage. Comprising approximately 140 , the genus inhabits a wide range of aquatic environments including freshwater, brackish, and marine habitats across all continents except , where they act as obligate parasites primarily targeting fishes. The biology of Argulus species features a direct life cycle without intermediate hosts, beginning with eggs laid in clusters on submerged or hard substrates; these eggs overwinter and hatch into free-swimming metanauplius larvae upon warming temperatures in spring (in temperate regions). The metanauplius larvae seek out and attach to hosts, developing into juveniles and then adults through multiple molts, capable of detaching to swim actively between hosts or mates. Unlike many aquatic parasites, Argulus retains strong swimming abilities throughout its life, facilitated by paddle-like appendages, enabling host-seeking, dispersal, and evasion behaviors; adults exhibit diurnal activity patterns, with males more active in light and females showing peaks at the onset of darkness. While feeding via a preoral stylet that pierces host tissue to extract blood and mucus, they can cause mechanical damage, secondary infections, osmoregulatory stress, and behavioral alterations in hosts, such as reduced feeding and increased susceptibility to predation. Ecologically, Argulus species play roles as regulators of fish populations in natural waters but are notorious pests in aquaculture and ornamental fish trades, where infestations—termed argulosis—lead to significant economic losses through mass mortalities, treatment costs, and reduced growth rates. Notable species include Argulus foliaceus, a widespread freshwater parasite in and affecting salmonids and cyprinids, and the invasive Argulus japonicus, which has spread globally via aquaculture shipments, impacting native fish biodiversity in regions like and . Control measures typically involve environmental management, such as removing vegetation to disrupt egg-laying sites, alongside chemical treatments like organophosphates or , though challenges persist due to the parasites' mobility and resistance development. Ongoing research focuses on biological controls, such as predatory , and to mitigate their impacts in both and systems.

Description and Morphology

Physical Characteristics

Argulus species are dorsoventrally flattened crustaceans characterized by an oval-shaped that covers most of the body, giving them a leaf- or shell-like appearance adapted for their parasitic lifestyle. The is broad and horseshoe-shaped, enclosing the fused and providing protection while allowing flexibility for movement. Adults typically measure 5–22 mm in length and 3–10 mm in width, with variation by and ; females are generally larger than males, though sizes can vary by environmental factors. The body segmentation includes a fused beneath the and an , or urosome, that is bilobed and unsegmented. The consists of four segments, the first of which is integrated with the , each bearing a pair of biramous swimming appendages equipped with spines and hooks that aid in locomotion and host attachment. The paired abdominal lobes extend posteriorly and often feature spines for securing to hosts. Externally, Argulus possess two compound eyes positioned anterolaterally on the dorsal surface, each comprising 20-100 ommatidia for vision. Adjacent to these is the naupliar eye, consisting of three pigment cups, each with an ocellus, providing additional photoreception. The four pairs of biramous swimming appendages facilitate active swimming, while a prominent preoral spine, located in the oral groove, serves as a piercing stylet for host tissue penetration. Sexual dimorphism is evident in several features, with females exhibiting a more rounded urosome and paired ovigerous spines on the for attaching eggs via mucous . Males, in contrast, have an elongated urosome and modified claspers on the anterior swimming legs, particularly the first pair, used for copulation and transfer. These differences support distinct reproductive roles, with the in both sexes contributing to reduced hydrodynamic drag during attachment to hosts.

Sensory and Attachment Structures

Argulus employs a suite of specialized attachment mechanisms to maintain firm to host fishes, ensuring effective . The primary organs for attachment are a pair of suction cup-like first maxillae, which function to hold the parasite in place on the host. These maxillae are supplemented by hooks on the antennal lobes and numerous spines distributed across the ventral lobes and underside, which collectively grip the host's skin and , resisting detachment during host movement. The flattened body shape further aids in this secure attachment by allowing close conformation to irregular host surfaces. The sensory systems of Argulus are adapted for detecting potential hosts in aquatic environments. A pair of large compound eyes, each comprising 20 to 100 ommatidia, provides vision for light detection and host location, enabling behaviors such as daylight "hover-and-wait" tactics. Complementing these are a median naupliar eye for basic orientation and navigation, particularly in low-light conditions. Chemoreceptors, including chitinous hair-like elements on the antennal spines and sensory setae on the maxillae, detect chemical cues such as host mucus and , enhancing host specificity and location day or night. The feeding apparatus integrates sensory and attachment functions to access host tissues. A prehensile preoral spine, a long and slender eversible structure, pierces the host's , while an associated stylet—a sheathed, hollow projection—facilitates penetration and the injection of anticoagulants and to liquefy tissues and promote flow for meals. Locomotion in Argulus relies on four pairs of biramous, leaf-like swimming legs, which propel the parasite during free-swimming phases for host seeking and dispersal, and also enable crawling over host surfaces once attached. These appendages, arising from the trunk, provide versatility between parasitic and planktonic lifestyles.

Taxonomy and Classification

Phylogenetic Position

The genus Argulus is classified within the kingdom Animalia, Arthropoda, Crustacea, superclass Oligostraca, class Ichthyostraca, subclass Branchiura, order Arguloida, Argulidae; it was originally established by O.F. Müller in 1785 as the of the . In earlier taxonomic schemes, Argulus and other branchiurans were placed under the class Maxillopoda, a grouping that encompassed diverse crustacean lineages including copepods and branchiurans based primarily on morphological similarities such as thoracic limb structure. Branchiura represents a monophyletic of obligate ectoparasitic crustaceans, with Argulus comprising the most speciose and widespread within the family ; molecular phylogenies confirm its position as sister to other branchiuran genera like Dolops and Chonopeltis. The divergence of Branchiura from free-living crustacean ancestors, as part of the broader Ichthyostraca (which also includes ), is estimated at approximately 500 million years ago based on analyses incorporating multiple genes and calibrations from related lineages. This early origin aligns with the basal position of Ichthyostraca within Oligostraca, supported by mitogenomic and nuclear ribosomal data. Key synapomorphies defining Branchiura include the development of suctorial mouthparts with specialized first maxillae forming attachment discs for host adhesion, a fused that envelops the trunk and aids in streamlining during free-swimming phases, and an abbreviated with hatching as a metanauplius rather than a full nauplius stage typical of many free-living crustaceans. These traits distinguish branchiurans from their sister group , which lack a and exhibit vermiform body plans adapted to endoparasitism in respiratory systems. Modern phylogenomic revisions have reclassified Branchiura from Maxillopoda to Ichthyostraca, driven by molecular evidence from 18S rRNA, 28S rRNA, and mitochondrial genes such as COI and 16S, which robustly support the monophyly of Ichthyostraca and its placement as sister to Ostracoda within Oligostraca. These analyses, incorporating multi-locus datasets, resolve previous morphological ambiguities and highlight the parasitic lifestyle as a derived trait within pancrustacean .

Species Diversity and Distribution

The genus Argulus comprises approximately 150 valid species (as of 2024), with ongoing taxonomic revisions potentially adjusting this figure; the type species is Argulus foliaceus (Linnaeus, 1758). These species inhabit a wide range of aquatic environments, reflecting a strong bias toward freshwater habitats globally. Notable species include A. foliaceus, which is widespread in temperate freshwater systems across , , and , often parasitizing a variety of fish hosts. A. japonicus has become a significant invasive parasite in aquaculture worldwide, originally native to but now established in , , , and the through human-mediated fish since the early 1900s. In contrast, A. coregoni specializes on salmonid fishes in and , showing increased host specificity as it matures. African species such as A. africanus, found in lakes and rivers of the continent, and A. rhipidiophorus, a parasite of African catfish, exemplify regional . Distribution patterns reveal a cosmopolitan range for the genus, native to all continents except , with highest species diversity concentrated in the Afrotropical and Neotropical regions, where environmental conditions support greater of freshwater ecosystems. Human activities, particularly the in ornamental and , have facilitated range expansions and invasions, notably for A. japonicus, leading to its establishment beyond native Asian distributions in , , and the by the mid-20th century.

Life Cycle and Reproduction

Developmental Stages

The life cycle of Argulus species exhibits direct development without intermediate hosts or prolonged free-living phases beyond the initial larval stage. Females deposit eggs in gelatinous strings containing 5–226 eggs each, with up to nine such strings produced per female, adhering them to hard substrates such as rocks, , or artificial surfaces away from the host. Incubation duration varies with and species, ranging from 10 to 80 days; for instance, A. japonicus eggs hatch in approximately 12 days at 25°C but require up to 61 days at 15°C. Eggs may enter during winter, remaining viable until warmer spring conditions trigger hatching, allowing overwintering populations to persist. Upon hatching, Argulus emerges as a free-swimming metanauplius , the first developmental stage, which relies on reserves for 1–2 days while actively seeking a host using sensory structures like antennae. This non-feeding phase transitions rapidly to the second stage, a parasitic juvenile form that attaches to the host via rudimentary suckers and claws, initiating a series of molts. Development proceeds through 9–10 juvenile instars (e.g., metanauplius plus nine juveniles in A. foliaceus, or up to 12 total stages with 11 molts), each molt enhancing morphological specialization for attachment and feeding, such as the development of thoracic legs and expanded . Early juvenile s, measuring 2–4 mm in length, primarily feed on host and epithelial cells using piercing mouthparts, causing minimal tissue penetration. In later s, specialized stylets fully develop, enabling blood-feeding by injecting enzymes to liquefy tissues and withdraw fluids, marking a shift to more invasive . The complete progression from egg to reproductive adult spans 30–60 days under optimal conditions (15–35°C), with warmer temperatures accelerating molting rates and shortening instar durations, while cooler waters prolong development. This temperature-dependent growth underscores the parasite's adaptation to seasonal freshwater environments.

Reproductive Biology

Argulus species are dioecious, featuring distinct male and female adults, with no confirmed hermaphroditism reported across studied taxa. Mating and copulation generally take place on the host or in free water, where the male employs genital pegs to interlock with the female's thoracic limb sockets, immobilizing her during sperm transfer. Sperm is delivered via a spermatophore through the vas deferens to the female's spermathecae, enabling internal fertilization; a single mating event suffices to fertilize all subsequent egg clutches produced by the female. Female fecundity is notably high, with individuals laying up to 400 eggs per clutch, typically arranged in 2–4 rows within gelatinous strings or mats. Multiple clutches—ranging from 1 to 10—are possible over the adult lifespan, potentially totaling hundreds to over 300 eggs per female in species like A. coregoni and A. siamensis. Eggs are attached to vegetation, rocks, or aquarium surfaces using ovigerous spines and a protective gelatinous coating, after which the female often returns to a host. As obligate ectoparasites, adult Argulus depend on host blood meals to fuel and sustain reproductive processes, with feeding essential for maturation and deposition. Off-host survival is limited to a maximum of 15 days without nourishment, underscoring their parasitic reliance, though adults can detach briefly for egg-laying. ratios are typically near 1:1 in natural populations, but deviations—such as female biases in A. foliaceus or male biases in A. japonicus—occur under high densities. has been rarely suggested in isolated cases but remains unconfirmed and is not a primary reproductive mode.

Ecology and Host Interactions

Habitat and Environmental Preferences

Argulus species predominantly occupy freshwater habitats, including lakes, ponds, and rivers, where they thrive in eutrophic conditions with abundant . While primarily associated with inland freshwater systems, certain species extend into brackish estuaries and marine coastal areas, demonstrating a wide tolerance from 0 to 35 parts per thousand (ppt). This adaptability allows them to exploit diverse aquatic niches, from oligohaline zones to full environments. Temperature plays a critical role in the survival, activity, and of Argulus. Optimal conditions for metabolic activity and occur between 15°C and 30°C, with peak reproductive rates observed at 20–28°C. Below 10°C, eggs enter a state of , enabling through winter months until warmer spring temperatures trigger . High temperatures above 35°C accelerate egg development but reduce off-host survival times for adults. Within these water bodies, Argulus favors still or slow-moving waters, such as stagnant ponds and shallow lake margins, where provides substrates for egg-laying. Females deposit eggs on plant stems, rough stones, or other hard surfaces in shaded areas, typically in depths less than 1–8 m to optimize access to potential hosts. Fast-flowing and rivers are generally avoided, as strong currents increase the risk of detachment from substrates or hosts. Additional abiotic factors influence Argulus distribution and persistence. They tolerate a wide range of levels, from 4.0 to 9.0, and maintain viability in waters with dissolved oxygen exceeding 4 mg/L, though they can endure lower oxygen conditions in polluted or eutrophic settings. This resilience contributes to their invasive potential in warm, stagnant ponds, where stable environmental conditions promote rapid and spread across global freshwater systems.

Host Range and Parasitic Behavior

Argulus species exhibit a broad host spectrum, primarily targeting fishes from various families, including (such as common carp Cyprinus carpio and Carassius auratus), (such as and ), (such as ), and (catfish like Ameiurus melas), with low host specificity across the and records of infestations on over 100 species worldwide. Occasional occurs on amphibians, including frogs and salamanders, as well as tadpoles, though remain the dominant hosts. This generalist strategy allows Argulus to exploit diverse aquatic environments where suitable hosts are available. Initial host contact occurs through free-swimming behavior, where parasites detect potential hosts using chemosensory cues from , prompting active pursuit in low-light or turbid conditions. Attachment typically begins on fins, gills, or thin-skinned areas using hooked antennae and maxillary suckers for secure grip, after which juveniles and adults may migrate across the host's body surface toward thicker regions for sustained feeding. This migration facilitates access to nutrient-rich sites, with adults often relocating to body flanks or flanks for blood meals, while causing localized irritation through mechanical action. Behavioral adaptations enhance parasitic success, including aggregation on stressed or injured hosts, where reduced host mobility increases attachment opportunities. Juveniles primarily graze on and epithelial cells, while adults pierce the skin to ingest blood, detaching periodically to deposit eggs on substrates or seek new hosts via thoracopod-mediated swimming. Transmission occurs directly through contact in dense, crowded waters, such as shoals or settings, and is often human-mediated via the transport of infested between ponds or fisheries.

Impacts and Management

Pathological Effects on Hosts

Argulus species inflict direct pathological damage on fish hosts primarily through their feeding mechanism, which involves piercing the skin with a stylet to extract blood and tissue fluids, resulting in hemorrhages, localized , and progressive tissue erosion at attachment sites. This blood-feeding behavior leads to significant , characterized by oligocythemic macrocytic hypochromic conditions and a notable decline in levels, particularly evident after several days of heavy . Severe cases also cause and scale loss, impairing and exacerbating issues. Infested fish exhibit distinct behavioral symptoms indicative of irritation and stress, including lethargy, erratic swimming patterns, and flashing—repeated rubbing against objects to dislodge the parasites. Additional signs encompass reduced feeding, increased mucus production over the body surface, and occasional surfacing behavior, which collectively weaken the host's overall vitality. The open wounds from Argulus attachment predispose hosts to secondary bacterial infections, such as those caused by Aeromonas species, and fungal invasions like Saprolegnia, which can rapidly escalate tissue damage and systemic illness. Furthermore, Argulus acts as a mechanical vector for viruses, including spring viraemia of carp virus (SVCV), facilitating their transmission between hosts during parasitic movement. At the population level, Argulus infestations impose high mortality rates, especially among juveniles, due to their vulnerability to debilitation and secondary complications. Infested experience reduced growth rates, with production losses estimated at 15-30% in affected populations, attributed to and impaired nutrient assimilation that are particularly pronounced in intensive environments.

Control and Prevention Strategies

Prevention of Argulus infestations begins with robust measures in and ornamental fish facilities. Quarantine of newly introduced fish, particularly wild-caught or pond-reared stock, is essential to detect and isolate potential carriers before integration into existing populations. Using fish-free or filtered source water prevents the introduction of free-swimming larvae or eggs through intake systems. Physical control methods target eggs and adults in the environment to break the life cycle. Removing or scraping substrates where females oviposit, such as pond bottoms or vegetation, reduces egg viability; drying affected areas for at least 48 hours effectively kills eggs by desiccation. Deploying trap boards or artificial substrates attracts ovipositing females, allowing collection and destruction of egg clutches; in one rainbow trout fishery, such boards harvested over 228,000 clutches in 14 weeks, reducing subsequent infestation prevalence by nine-fold. UV irradiation of water in recirculating systems may inactivate free-swimming stages, though it is more commonly applied for overall pathogen control. During off-seasons, draining and drying ponds eliminates residual parasites and eggs. Mechanical removal, such as shaking infested fish in nets for 20-30 seconds, detaches over 80% of adults from hosts like rainbow and brown trout. Chemical treatments provide targeted intervention but require caution due to potential and regulatory restrictions. Organophosphates like trichlorfon, applied at 0.25-0.5 mg/L active ingredient in weekly baths for four treatments, effectively control adults and juveniles, though availability is limited as the product is no longer manufactured in some regions. Pyrethroids such as are used in to target Argulus, often in low doses to minimize environmental impact. synthesis inhibitors like interrupt molting in larvae and adults, following label instructions as a restricted-use ; lufenuron at 0.13 mg/L similarly disrupts development. baths at 2-10 mg/L for 30 minutes, or 1.3 mg/L applied twice over three days, achieve high mortality in freshwater systems and are approved for food fish . Treatments should avoid use on food fish without regulatory approval to prevent residue concerns. Integrated pest management (IPM) combines these approaches for sustainable control, minimizing reliance on chemicals to avoid resistance. Regular monitoring of levels through visual inspections or sampling prompts timely intervention, often integrating environmental manipulations with physical removals. Biological methods, such as deploying or predator species, show promise but require further validation; trap boards exemplify a low-impact biological tactic by exploiting oviposition behavior. Combining methods—e.g., quarantine with periodic chemical baths and substrate management—has reduced Argulus populations in managed fisheries while preserving balance.

References

  1. https://www.calacademy.org/scientists/ichthyology/wpoly/argulus
  2. https://edis.ifas.ufl.edu/publication/FA184
  3. https://ojs.library.okstate.edu/osu/index.php/OAS/article/view/7204/6637
  4. https://www.gbif.org/species/13533166
  5. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/branchiura
  6. https://www.sciencedirect.com/science/article/abs/pii/S0306456520304599
  7. https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-015-1005-0
  8. https://pmc.ncbi.nlm.nih.gov/articles/PMC9557303/
  9. https://canalrivertrust.org.uk/things-to-do/fishing/caring-for-our-fish/guide-to-fish-health/argulus-fish-louse
  10. https://animaldiversity.org/accounts/Argulus_foliaceus/
  11. https://invasions.si.edu/nemesis/species_summary/206252
  12. https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1136&context=usfwspubs
  13. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/argulus
  14. https://www.researchgate.net/publication/352280276_Morphological_and_molecular_description_of_Argulus_indicus_Weber_1892_Crustacea_Branchiura_found_from_striped_snakehead_fish_Channa_striata_in_Lake_Towuti_Indonesia
  15. https://link.springer.com/chapter/10.1007/978-3-031-83903-0_6
  16. https://pmc.ncbi.nlm.nih.gov/articles/PMC4513377/
  17. https://www.researchgate.net/publication/230012770_On_the_Morphology_and_Classification_of_Argulus_Crustacea
  18. https://www.marinespecies.org/aphia.php?p=taxdetails&id=104071
  19. https://www.invasive.org/browse/subinfo.cfm?sub=63165&cat=84
  20. https://pmc.ncbi.nlm.nih.gov/articles/PMC10999652/
  21. https://www.tandfonline.com/doi/full/10.1080/14772000903562012
  22. https://academic.oup.com/mbe/article/30/1/215/1021983
  23. https://www.sciencedirect.com/science/article/abs/pii/S1467803907000953
  24. https://pmc.ncbi.nlm.nih.gov/articles/PMC7124122/
  25. https://www.researchgate.net/publication/367662278_Tying_the_Knot_Further_Molecular_Data_Agree_that_Branchiura_and_Pentastomida_Form_the_Monophyletic_Ichthyostraca_Despite_Their_Extensive_Morphological_Differences
  26. https://pubmed.ncbi.nlm.nih.gov/18394959/
  27. https://pmc.ncbi.nlm.nih.gov/articles/PMC10414812/
  28. https://www.sciencedirect.com/science/article/abs/pii/S1467803909000875
  29. https://link.springer.com/chapter/10.1007/978-1-4020-8259-7_22
  30. https://www.sciencedirect.com/science/article/abs/pii/S1050464824004960
  31. https://arccjournals.com/journal/indian-journal-of-animal-research/B-5455
  32. https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=166
  33. https://pubmed.ncbi.nlm.nih.gov/17626688/
  34. https://www.cabidigitallibrary.org/doi/full/10.1079/cabicompendium.93571
  35. https://www.marinespecies.org/aphia.php?p=taxdetails&id=357251
  36. https://pmc.ncbi.nlm.nih.gov/articles/PMC4408894/
  37. https://www.researchgate.net/publication/232890822_The_developmental_sequence_of_Argulus_foliaceus_Crustacea_Branchiura
  38. https://orca.cardiff.ac.uk/id/eprint/149973/1/2022huntphd.pdf
  39. https://assets.publishing.service.gov.uk/media/5a7cdfdeed915d7c849adc29/scho0705bjik-e-e.pdf
  40. https://onlinelibrary.wiley.com/doi/abs/10.1002/jmor.20364
  41. https://www.researchgate.net/profile/Samar-Saha-2/publication/236346578_Life_Table_and_Fecundity_of_Argulus_siamensis_A_Cohort_Based_Study/links/5707c02008aea660813317e0/Life-Table-and-Fecundity-of-Argulus-siamensis-A-Cohort-Based-Study.pdf
  42. https://edoc.ub.uni-muenchen.de/19236/1/Merk_Teresa.pdf
  43. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/arguloida
  44. https://pubmed.ncbi.nlm.nih.gov/32888555/
  45. https://pmc.ncbi.nlm.nih.gov/articles/PMC3793081/
  46. https://e-journal.unair.ac.id/JAFH/article/download/54102/28026/281482
  47. https://pubmed.ncbi.nlm.nih.gov/25127735/
  48. https://pubmed.ncbi.nlm.nih.gov/22322389/
  49. https://www.vliz.be/imisdocs/publications/375071.pdf
  50. https://repository.ubn.ru.nl/bitstream/handle/2066/45173/45173_argu.pdf
  51. https://pubmed.ncbi.nlm.nih.gov/15109143/
  52. https://www.jstor.org/stable/20105939
  53. https://onlinelibrary.wiley.com/doi/full/10.1111/jai.14287
  54. https://www.cfsph.iastate.edu/Factsheets/pdfs/spring_viremia_of_carp.pdf
  55. https://medcraveonline.com/MOJES/status-occurrence-intensity-and-impact-of-argulosis-in-different-brood-stock-ponds.html
  56. https://ojs.unimal.ac.id/acta-aquatica/article/view/584
  57. https://www.int-res.com/articles/dao2008/82/d082p067.pdf
  58. https://www.researchgate.net/publication/230156697_Biological_control_of_the_fish_louse_in_a_rainbow_trout_fishery
  59. https://www.fao.org/fishery/docs/CDrom/aquaculture/a0845t/volume2/docrep/field/003/ac160e/AC160E04.htm
Add your contribution
Related Hubs
User Avatar
No comments yet.