7Challenges of IMTA in warm,

oligotrophic and exposedwaters

Demetris Kletou1,2, Jason Hall-Spencer2, Periklis Kleitou1

and Eleni Nikita3

1. Marine & Environmental Research (MER) Lab Ltd2. University of Plymouth3. Seawave Fisheries Ltd

1. Introduction

2. Lessons learned from IMTA trialso Musselso Sea Urchinso Oysterso Abaloneo Blue Crabso Sponges

3. Main Conclusions

Contents

1.Introduction

1. Introduction

SW operates at 37-43 m depth

<1.5 km from touristic Governor’s beach

Near many other anthropogenic activities

Governor’s Beach(restaurants)

Ports

Electricity Power

Oil & Gas

CementFactory

Fish Farms

N

1. IntroductionThe most oligotrophic SME studysite with chl.a concentrations most

times below 0.1 μg/L

Terra MODIS chlorophyll annual average 2000-2015

1. IntroductionThe warmest SME study site with

temperatures averaging around 20 oCand ranging between 15 – 30 oC

Terra MODIS chlorophyll annual average 2000-2015

1. IntroductionEnvironmental conditions are ideal for finfish culture• Warm and oxygenated – so fast growth rates (sea bream and sea bass reach

harvesting size at 12-14 months)• Oligotrophic – low pathogenicity (no antibiotics)

However• Temperatures in summer are above the thermotolerance levels of many

species• Little background particulates for many filter-feeders• Lack of nutrients means it is unsuitable for macroalgae

2. IMTA trials – Lessons Learned

2. IMTA trials – Lessons Learned

Pilot scale experiments

Trials included an array organisms(mussels, oysters, sea urchins, abalone, crabs, sponges)

But mostly limited to native species that couldbe supplied by hatcheries

2. Lessons learned

Three Trials with mussels

(Mytilus galloprovincialis)

Duration: Month 6-47

2. Lessons learned (Mussels)

1° batchShipped from Greece

Problems:

• Long transit

• Unsuitable temperatureduring transport

2. Lessons learned (Mussels)1st batch deployed at 3 depths

Longlines around cages

2. Lessons learned (Mussels)

Four Months Later

2. Lessons learned (Mussels)

About a Year Later

2. Lessons learned (Mussels)

15 months later

2. Lessons learned (Mussels)

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2. Lessons learned (Mussels)

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SHALLOW MIDDLE DEEP AVG

2. Lessons learned (Mussels)

Conclusions:

Losses especially near the surfaceSuspected high temperatures and turtle predation

Survivors however grew to almost commercial size, butstagnated growth and reduction in mussel yield duringthe summer oligotrophic season

2. Lessons learned (Mussels)

2° batchShorter transit at appropriate temperatures andprompt deploymentDeployed at mid-waters

Problems:• Delayed shipment due to biotoxins at the point of

origin• <2 months following deployment a big storm

claimed almost the entire batch

2. Lessons learned (Mussels)

Following the storm

2. Lessons learned (Mussels)Remaining mussels monitored

until the end of project

2. Lessons learned (Mussels)Heavy biofouling also observed

in October

2. Lessons learned (Mussels)

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Mussels 2nd Batch

2. Lessons learned (Mussels)Conclusions:Losses of first batch could have been due to naturaldislodgment of mussels and not necessarily due to heatinduced mortalities.

Reduction in meat mussel yield in warm season,associated with development of competing biofouling.

Can reach commercial size in two years.

The classical production method using longlines may notbe suitable in these conditions.

2. Lessons learned (Mussels)3° batch

Shipped from samesupplier with no transitproblems

Deployed in cages (empty,sea bass and sea bream)

2. Lessons learned (Mussels)Most Mussels found dead in

sea bream cages

2. Lessons learned (Mussels)

Possibly eaten by sea bream

2. Lessons learned (Mussels)

Different story in sea bass(can co-exist)

2. Lessons learned (Mussels)

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Seabass cage Empty Cage

2. Lessons learned (Mussels)

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Seabass Cage

Empty Cage

2. Lessons learned (Mussels)Conclusions:

The interactive co-cultivation of mussels with seabass is possible (not the case in sea bream),

Mussels grow and survive, detached musselscontinue to grow on the net, culturing in cages canbe a more appropriate technique rather thanlonglines in exposed waters,

Very high survival rate in empty cages.

2. Lessons learnedTwo trials with sea urchins (Paracentrotus lividus)Duration: Month 12-21, 36-48

2. Lessons learned - Sea Urchins1° TrialCollected from a dense naturalpopulation

Deployed in benthic (34 m deep)enclosures (1 m2)

Were not fed

Experiment lasted 8 months

2. Lessons learned - Sea UrchinsCleared Macroalgae,

reduced OM

2. Lessons learned - Sea UrchinsBut after a while…

2. Lessons learned - Sea Urchins

Little gonadal development

2. Lessons learned - Sea Urchins

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Sea Urchins

2. Lessons learned (Mussels)

Conclusions:

Sea urchins didn’t develop gonads and most die ifnot fed but can reduce OM in the sediment.

Benthic experiments not practical/safe at Cypriotfarms using divers, as most now operate >40 mdepth.

2. Lessons learned - Sea Urchins2° TrialSmall numbers cultivated in Ortacbaskets and in cages

In cages – fed on biofouling

In Ortacs – fed mainly macroalgaefrom the farm structure

2. Lessons learned - Sea Urchins

Clearing biofouling from the nets offers benefits to the farmers

2. Lessons learned - Sea Urchins

In cages sea urchins died after a while, but very high survival in Ortac baskets

2. Lessons learned - Sea Urchins

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Sea Urchins (Ortacs)

Gonads developed!

2. Lessons learned - Sea UrchinsConclusions:

Sea urchins didn’t survive in the cages but veryhigh survival rate in Ortacs,

Commercial size gonads reached in late summer inOrtacs

A drawback is that the sea urchins had to be fedcontinuously which was not practical andmacroalgae are not always abundant on the farmstructures.

2. Lessons learned

Trials with oysters

(Ostrea edulis)

Duration: Month 23-36

2. Lessons learned - OystersWere shipped from Scotland

Problems:• Long Transit• Delayed changing baskets

(heavy biofoulingdeveloped)

• Lost two baskets to thestorm

• Predation by crabs

2. Lessons learned - OystersDeployed in Ortacbaskets (~15 m depth)

2. Lessons learned - Oysters

Heavy BiofoulingDeveloped

2. Lessons learned - Oysters

Even in the inserts

2. Lessons learned - Oysters

Many diedSurvivors grew slowly

2. Lessons learned - Oysters

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Ortacs Changed

2. Lessons learned - Oysters

Scallops often found in mostinserts & baby mussels

2. Lessons learned - OystersPinna nobilis much larger than oysters

2. Lessons learned - OystersConclusions:

Low survival rate so oysters may not form a goodcandidate IMTA co-cultivar.But spike in growth following basket changes, sotheir slow growth may be due to competingbiofouling.Large numbers of dead oysters may be due topredation by crabs or competing biofoulingLocally abundant scallops and P. nobilis seem to bemore promising candidates

2. Lessons learned

Trials with abalone

(Haliotis tuberculata)

Duration: Months 32-47

2. Lessons learned - AbaloneWere shipped from France

Problems:• Bad packaging• Slow reaction time• Many died first two days• Lost two sets with four

baskets due to weather• Require feeding every 10

days

2. Lessons learned - Abalone

Some trialled infish cages, butfailed

2. Lessons learned - AbaloneMost placed inOrtac basketshanged from fin-fish cages.

High survival rates,but not muchgrowth recorded.

2. Lessons learned - Abalone

Fed mainlyUlva andDictyota everyabout 10 dayswhich was notalwaysabundant andabalonestarved manytimes

2. Lessons learned - AbaloneConclusions:

Abalone have high survival rate and seem to forma promising candidate IMTA species but need toensure constant food supply as growth was limitedby the availability of food,

Cannot be grown in nets but can be grown inbaskets,

Perhaps in land-based systems their culture ismore practical.

2. Lessons learned

Trials with blue crab

(Callinectes sapidus)

Duration: Months 33-36

2. Lessons learned – Blue CrabsWere shipped from Greece

Problems:• Territorial and agressive• Require feeding every 3-4

days which is not practical• Displayed little growth• Not sustainable with this

type of production system

2. Lessons learned – Blue CrabsConclusions:

Could grow on the dead fish diet so can provide analternative for discarded fish,

Territorial character - growing them in baskets isnot practical,

Perhaps in a land-based system they could bemaintained/fed practically.

2. Lessons learned

Trials with sponges

(Spongia spp.)

Duration: Month 43-48

2. Lessons learned - SpongesTried 2 different methods: i) the kebab and ii) the mesh method.Both hanged from the farm structures.

2. Lessons learned - SpongesThe kebab method failed, due to tear of sponges.

2. Lessons learned - SpongesThe mesh method has biofouling issues, but seems to work

One Month Later

Three Months Later

2. Lessons learned - SpongesHigh survival and growth observed but short experiment

2. Lessons learned – Sponges

Conclusions:

High survival rate, promising IMTA species buthave slow growth rates

The structures should be placed near the seabottom and not attached to the farm to reduce theeffect of the wave energy

3. Main ConclusionsLimitations & Opportunities

3. Main Conclusions – LimitationsFailure of many crops trialled.Could be due to an array of reasons. For example:• Environmental unsuitability,• Exposed conditions (storms) associated with technical

failures,• Inappropriate transport or response time,• Lack of macroalgae year round to feed herbivorous

species,• Lack of hatcheries to produce many species with

potential (locally abundant).

3. Main Conclusions – Opportunities• Mussels could work but have to be kept suspended

inside cages to remove predation and losses due tobad weather,

• Other bivalves that could work include scallops andthe protected Pinna nobilis,

• Herbivores like sea urchins and abalone could work ifconstant supply of food is assured (could be in theform of dried seaweed),

• Crabs could work but in land-based systems,• Bathing sponges have shown much potential but have

to be placed near the bottom and have slow growthrate.

3. Main Conclusions – Further NEEDS• Research at hatcheries to produce spat/juveniles of

potential native species to stock IMTA units,• Research to identify appropriate culturing practices

(timing of culture/harvest, equipment that is practicaland durable in exposed sites),

• Need to train fish farmers on the grow-out ofinvertebrates and equip them with appropriate tools(e.g. mussel declumpers, graders, depurationsystem),

• Technology transfer to channel effluent streams,• IMTA provides an excellent opportunity to grow extra

crop and diversify production.

PARTNERS

The research leading to these results has been undertaken as part of the IDREEM project(Increasing Industrial Resource Efficiency in European Mariculture, www.idreem.eu) and has

received funding from the European Union's Seventh Framework Programme (FP7/2007-2013)under grant agreement n° 308571.

We want to thank the personnel of MER and SW who assisted the collection of data, namely Foteini Georgiou,Alexandros Loucaides, Polina Polycarpou, Maria Rousou, Apostolos Rokomos, Demetris Louca and all others

who contributed to smaller extents. Without them it would have been very difficult to carry out this work.

Questions?For more information about the IDREEM project

visit our website:

www.idreem.eu