1. and Atlantic Salmon By Jonathan Sheppard
GYRODACTYLUS SALARIS
and Atlantic Salmon By
Jonathan Sheppard

2. Main Points
Gyrodactylus Salaris Identification (Morphology, Life Cycle, Discovery and Origination)
Spread Pathways (Anthropogenic, Migration)
Impacts (Ecologically, Economically)
Management Methods (Prevention, Eradication)

3. Gyrodactylus Salaris Monogean skin/salmon fluke
First discovered in 1957 in Sweden
The host is the atlantic salmon parr
“Salmon Killer”

4. Gyrodactylus Salaris Simplest life cycle
Hyper-vivaparous and external (outside the host) reproductive strategy
Progenesis
“Russian Doll Effect”

5. 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

6. Pathways of
Spreading in G. Salaris

7. 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

8. 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

9. 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

10. Ecological and Economical
Impacts of G. Salaris

11. 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

12. Ecological Impact Signs of the disease are Ulcers on the skin
Peeling of the skin
Fish appearing pale
Excess mucus on the skin

13. 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

14. 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 %

15. Management Strategies
Prevention, Eradication and Education
Management Strategies

16. Management Strategies
Management strategies differs between countries
Norway and Sweden’s strategy is eradication
Denmark and Scotland are taking prevention and education strategies

17. Prevention and Education
Strict regulations are enforced on importing live
Norway has produced posters to spread along rivers and methods to educate fishermen and others
Some use of migration obstructions

18. 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

19. Further Research about G. Salaris
Subdivisions of Gyrodactylus genus
Patterns of host specificity and host preference and evolutionary mechanisms of host switching

20. 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 Date of access x/x/200x.
Johnson, E. Skin Flukes (Gyrodactylus) Frank Prince-Iles ©2009 All Rights Reserved
Manual of Diagnostic Tests for Aquatic Animals
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
Overview of the genus Gyrodactylu. Overview of the genus Gyrodactylusshttp://
Aquatic Animal Diseases Significant to Asia–Pacific Identification Field Guide. Parasitic diseases—Gyrodactylosis.