Download gyrodactylus salaris

GYRODACTYLUS SALARIS
and Atlantic Salmon
By
Jonathan Sheppard
Main Points
 Gyrodactylus Salaris Identification (Morphology, Life
Cycle, Discovery and Origination)
 Spread Pathways (Anthropogenic, Migration)
 Impacts (Ecologically, Economically)
 Management Methods (Prevention, Eradication)
Gyrodactylus
Salaris
- Monogean skin/salmon fluke
-
First discovered in 1957 in
Sweden
-
The host is the atlantic
salmon parr
-
“Salmon Killer”
Gyrodactylus
Salaris
-
Simplest life cycle
-
Hyper-vivaparous and
external (outside the host)
reproductive strategy
-
Progenesis
-
“Russian Doll Effect”
Gyrodactylus
Salaris
Morphology
-
Attaches to host with its
posterior opisthaptor with
16!!! Sharp hooks
-
Feeding occurs in the anterior
end sucking up skin tissue
and mucous
Pathways of
Spreading in G. Salaris
G. Salaris Spread
• Originates from 3 native
regions; Russia, and Baltic
regions of Finland and
Sweden
• In these regions the salmon
have little to intermediate
infection responses to G.
Salaris
G. Salaris Spread
• G. Salaris now reaches the
atlantic salmon population in
Norway, Denmark and the
west coast of Sweden
• Norway has recorded over 41
of their river systems being
infected
Spread Pathways
• Anthropogenic movement of
infected fish between
hatcheries and fish farms in
rivers
• Migration of infected fish in
rivers and in brackish water
through fiords
• Through the host transfer of
other species of freshwater
fish that does not support the
parasite
Ecological and Economical
Impacts of G. Salaris
Ecological Impact
 Infection from G. Salaris
results in GYRODACTYLOSIS,
early stages are:

Irritation; fish will undergo
behaviours of rubbing and flashing
 Later stages:

Lethargic and isolating behaviours
 G. Salaris and secondary
infections ultimately lead to
mortality
Ecological Impact
 Signs of the disease are




Ulcers on the skin
Peeling of the skin
Fish appearing pale
Excess mucus on the skin
Ecological Impact
- Specificity
 <100 in abundance sites are
located on dorsal fin, pectoral
and anal fin
 >100 site specificity moves to
the caudal fin
 >1000 the body was infected
Economic Impact
 The density of salmon parr in
14 of norways rivers have
been reduced by 86%!!!
 Since G. salaris’ discovery in
norway 25 years ago it has
cost >500 million euros
 Without any measures, the G.
salaris may have reduced the
Norwegian salmon fishery by
15 %
Prevention, Eradication and Education
Management Strategies
Management
Strategies
o Management strategies
differs between countries
o Norway and Sweden’s
strategy is eradication
o Denmark and Scotland are
taking prevention and
education strategies
Prevention and Education
o Strict regulations are enforced on importing live
o Norway has produced posters to spread along rivers
and methods to educate fishermen and others
o Some use of migration obstructions
Eradication
 Rotenone is used as a widespread chemical in the
river systems
 Has proven to be effective in smaller rivers
 Laboratory experiments have shown effectiveness
with acid aluminum
Further Research about G. Salaris
 Subdivisions of Gyrodactylus genus
 Patterns of host specificity and host preference and
evolutionary mechanisms of host switching
References
 Johnsen B.O. (2006): NOBANIS – Invasive Alien Species Fact Sheet – Gyrodactylus
salaris. – From: Online Database of the North European and Baltic Network on Invasive
Alien Species – NOBANIS www.nobanis.org, Date of access x/x/200x.
 Johnson, E. Skin Flukes (Gyrodactylus) Frank Prince-Iles ©2009 All Rights Reserved
http://www.fishdoc.co.uk/disease/flukes.htm
 Manual of Diagnostic Tests for Aquatic Animals 2009.
www.oie.int/fileadmin/Home/eng/Health_standards/aahm/2010/2.3.03_Gyrodactylosis.
pdf
 Baake, T. et al. The Biology of Gyrodactylid Monogeneans: The ‘‘Russian-Doll Killers’’.
ADVANCES IN PARASITOLOGY VOL 64
 Baake, T. et al. DISEASES OF AQUATIC ORGANISMS. lished June 18 http://www.intres.com/articles/dao/13/d013p063.pdf
 Overview of the genus Gyrodactylu. Overview of the genus
Gyrodactylusshttp://www.gyrodb.net/biology.php
 Aquatic Animal Diseases Significant to Asia–Pacific Identification Field Guide. Parasitic
diseases—Gyrodactylosis.
http://library.enaca.org/Health/FieldGuide/html/fp001gyr.htm