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Pathogen (name, taxonomy, description):
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Lernaeolophus
sultanus
Parasite classification:
Phylum: Arthropoda
Subphylum: Crustacea
Class: Maxillopoda
Subclass: Copepoda
Infraclass: Neocopepoda
Superorder: Podoplea
Order: Siphonostomatoida
Family: Pennellidae
Genus: Lernaeolophus
Species: Lernaeolophus
sultanus
Lernaeolophus sultanus (Pennellidae) is a cosmopolitan copepod species parasitizing
on marine fish. It has been recorded from the Atlantic, Pacific and Indian
Oceans as well as from the Mediterranean Sea.
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Economic Implications:
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Slight
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Frequency of occurrence:
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Rare
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Susceptible farmed species,
age/size and regional pertinence:
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 During the late autumn of the
years 2005 and 2006 this “anchor worm” has been observed on caged sea bass (Dicentrarchus
labrax) and sharp snout sea bream (Diplodus puntazzo) during
routine fish handling, such as vaccination and grading. The fish were 50-150g
average body weights and the farms were situated in the Corinthian and
Maliakos Gulfs (arrowed areas on the map).
The rate of infection did not exceed 0.1% and
the affected fish did not carry more than a single parasite. Mortalities were
not evident.
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Fish lesions and parasite
morphology:
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The parasites
exhibited attachment site specificity. The eye sockets, the mouth bony vault,
the tongue and the opercula, comprised the usual sites of attachment. The
area around the anus and the anal fin was a less common attachment site.
The
visible parts of the anchored parasite comprised its flexed 6-10mm abdomen
with its 4-7mm long, straight or branched, caudal processes.
   
  
The
cephalic part with its branched processes (antlers, or cephalic horns) as
well as the 7-10mm long tube-like neck linking it to the abdomen, were
invariably found to have burrowed deep into the host tissues, causing damage
and deformities to the bone and cartilage, destroying the olphactory
epithelium, or the tissues behind the eyeball.
These
localized deformities together with inferior body condition and growth
retardation characterized the parasitized fish.
The
anchor worms could be removed by pulling, but the cephalic processes were cut
off and remained embedded in the host tissues.
Bar distance = 1mm.
 
 
The caudal processes of the parasite
portrayed a strong thick wall and occasionally contained crystallised masses.
   
Parasites
with a developed single spiral egg sack, carrying a row of stacked maturing
ova, were found on sharp snout sea bream, but not on sea bass.
This finding may show a case of parasite adaptation
to alternative hosts and progressive transfer of the parasitism from wild
fish hosts to the farmed fish species due to their relative abundance in the
heavily farmed areas. The presence of mature parasites on farmed fish may
pose a future threat to marine aquaculture in Greece.
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Diagnosis (field,
laboratory):
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Gross observation of the parasites
attached to their most common sites of attachment on the fish skin or mouth
with associated localised lesions and deformities as well as poor body condition.
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Mild
consequences
(growth reduction, extra labour):
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Costs associated with anchor worm
(copepod) infestations of farmed fish may be:
1.
Rejections at harvest (degraded fish).
2. Extra labour to inspect and grade fish at the packing plant (quality).
3. Chronic stress and high propensity to other diseases (indirect mortality).
4. Growth retardation.
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Environmental issues:
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The
parasitic copepods come from wild fish, although this particular anchor worm has
not been observed on the common wild species that are seen around the net
pens (Mugil spp., Liza spp., Boops boops, Boops salpa, Lithognathus
mormyrus, etc.). However, if Lernaeolophus sultanus manages to
mature on the farmed species, then the farms would be expected to amplify
further and spread the parasite.
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Regulations:
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No
regulations are in place. Parasitism by anchor worms is limited and poses no
risk for the consumer.
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Selected Bibliography:
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Valdes, P. and
Abellan, E. (2004) Prevalence of the parasitic copepod Lernaeolophus
sultanus (Pennellidae) in common Pandora (Pagellus erythrinus)
from Mazarron Bay (SE Spain). Poster presentation at the EAS conference
“Aquaculture Europe 2004” [p.811]
Suarez-Morales,
E. and Ho, J.S. (1994) Lernaeolophus sultanus (Nordman, 1864)
(Copepoda), a parasite of Lutjanus camperchanus (Poey) in the Gulf of
Mexico. Bull. Mar. Sci., 55(1):246-248
Grabda, J. (1991)
Marine Fish Parasitology. PWN-Polish Scientific Publishers, Warszawa pp.304
Natarajan, P. and
Nair, N.B. (1977) On the Occurrence of Lerneaolophus sultanus
(Nordmann) on Priacanthus hamrur (Forskal). Current Science 46(3):93-94
Grabda, J. (1972)
Observations on penetration of Lernaeolophus sultanus (Milne Edwards, 1840)
(Lernaeoceridae) in organs of Pneumatophorus colias (Gmelin, 1788). Acta
Ichthyol. Piscat. 2(1):115-125
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Acknowledgements
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The personal communications
with Dr Angelo Colorni (Eilat, Israel) and Dr Francesc Padros (Barcelona,
Spain) are thankfully acknowledged.
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