CLEANERFISH USE IN

MOWI IRELAND

JOHN POWER AND ABDON RYAN

MOWI SOUTHWEST

SEA LICE IN SALMON FARMING• Sea lice species Lepeoptheirus salmonis and Caligus

spp. are found in wild and farmed salmonids in

Ireland.

• Sea lice are an external parasite that feed on the

mucosal layer leading to scale loss and bacterial

infections.

• Sea lice are one if the biggest factors effecting the

health of farmed salmon worldwide, cost of

treatment in Norway in 2018 was €144.8 million.

Image of all Lep.life stages

Sea lice attached to head of salmon

Egg-bearing adult female Lep. Salmonis

TIME SCALE

• 2014: Small scale trials carried out

• 2015: Wild caught wrasse and hatchery reared

lumpfish first deployed

• 2016/2017: Increased use on all Irish sites

• 2018: All MHI sites now using Cleanerfish with

improving efficacy and health a larger focus

• 2019: Carrying out trials to improve over all

health and develop Operational Welfare

Indicators (OWI’s)on site

• Positive results on the majority of sites with

cleanerfish deployed, resulting in a reduction in

the use of chemicals in some areas

LICE TREATMENTS

• Chemicals were previously the most common form

of treatment but have some downsides

• Limited use when maintaining organic standard

• Lice can build up a resistance

• Mechanical treatments are becoming more

popular and widespread e.g. hydro-licer and

thermo-licer, these can be extremely costly and

resettlement can be high post-treatment

• Cleanerfish are a more sustainable treatment

alternative when maintaining an organic standard.

• They operate best when implemented as a

preventative measure prior to lice outbreak

CLEANERFISH SPECIES

Ballan Goldsinny Cuckoo

Corkwing Rock Cook Lumpfish

STOCKING PRACTICES

• Stocking of wild wrasse is aimed at between 6-8% during the summer depending on lice burden.

• Wrasse sourced locally where possible

• Hatchery reared lumpfish are stocked to 5% during the winter.

• Additional wrasse or lumpfish can be stocked if lice levels show an increase or remain the same.

Lumpfish transport truck Cleanerfish transport tanks Transferring wrasse into pens

HIDES• 1m of hide to 30-50 cleanerfish (depending on size)

• Essential for maintaining good condition on all cleanerfish

• Various materials can be used:

• Curtain (Artificial kelp)

• Barrel

• Lumpfish can require solid structures to rest on or an area to shelter in stronger tides

FEEDING• Wrasse and lumpfish both

require regular feeding to

maintain condition

• Wrasse graze on feeding blocks

• Biomar wrasse feeding blocks

• Lumpfish are hand fed pellets

(2% Biomass)

• Skretting Clean Lumpfish

• Feed should be distributed into

the hide directly to avoid salmon

coming in contact

Wrasse feeding block

Lumpfish pellets on left

Lumpfish feeding

TREATMENTS AND HEALTH CHECKS

• All cleanerfish species are

susceptible to AGD

• Lumpfish can be treated with a

2-3hr FW treatment.

• Wrasse are removed when

treating with FW and treated

with H202.

• Methods for removal:

• Potting

• Grading/dewaterer

• Health checks are carried out

on elevated mortalities

H2O2 treatment for AGD on site

Gill inspection wrasse

WRASSE EFFICACY Graph showing the increasing stocking numbers of wrasse plotted against

the declining number of Lepeoptheirus salmonis present in a salmon smolt

site.

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

27 28 29 30 31 32 33 34 35 36 37

% W

rass

e

Lep

. C

ou

nt

Week

Wrasse Efficacy Grower Salmon Summer 2018

Total Lep

Female Lep

Wrasse %

CONTINUED…Graph showing the increasing stocking numbers of wrasse plotted against

the declining number of Lepeoptheirus salmonis present in harvest size

salmon, in pens stocked at the start of the summer.

0

1

1

2

2

3

3

4

0

1

2

3

4

5

6

25 27 28 29 31 33 34 35 36 37

Wra

sse

%

Lep

. C

ou

nt

Weeks

Wrasse Efficacy Grower Salmon Summer 2018

Female Lep

Total Lep

Wrasse %

LUMPFISH EFFICACY

0.00

0.10

0.20

0.30

0.40

0.50

0.60

41 42 43 45 46 48 49 50 51 2 7 8 9

Tota

l Fe

ma

le L

ep

.

Weeks

Lumpfish Efficacy Winter 2018/2019

30'000 Lumpfish Stocked

Graph showing the increasing stocking numbers of wrasse plotted

against the declining number of Lepeoptheirus salmonis present in

salmon smolts.

FUTURE WORK/CONCLUSION

• More trials to be carried out on welfare in collaboration with other groups.

• The higher the condition of the fish the more productive lice eaters they will be.

• Preparation is very important before stocking cleanerfish.

• Very good developments have been made since the first use of cleanerfish.

• Still work to be done on some aspects to get it right (i.e. pre-treatment removal)

THANK YOU!