Tuesday, 16 September 2014

Day 16- Change of methods and calibration of water monitoring.

Me and Felix monitoring water parameters and picking up water samples for spectro analysis (credits: Emilie Devic).

For making the methodology more exact and correct, we adopted a new way for recording the daily feed intake. 
Taring a container (credits: Nicole Pelusio).

Weighting feed (credits: Nicole Pelusio).

Filling up the bucket for daily intake (credits: Nicole Pelusio).

 Per each cage we bought a bucket with lid which can be filled with a certain and known quantity of feed inside, bring it on cage, feed the fish on demand for the whole day. 

Feeding each cage with its own bucket (credits: Nicole Pelusio).

Then at the end of the day we weighted the left feed and repeat the process every-day for a good estimation of feed intake.
Drying the bucket at the end of the day (credits: Nicole Pelusio).

Weighting the bucket with the rest of uneaten feed (credits: Nicole Pelusio).

For checking if in the water there is any modify in parameters, we measure DO, pH and temperature some exact times during the day with probes. Concerning the water quality parameters such as Alkalinity, Ammonia, Nitrites, Nitrates, Hardness and Potassium etc. We collect water samples (one per each cluster) and store them in a cool place waiting for the arriving of spectrophotometer.

Day 15- Sun bite and paddling.

Joining on bord with Felix and Michael checking the notes and data of the day (credits: Nicole Pelusio).

This morning Emilie joined me and Felix only in the morning, then before leaving the fish farm and Ghana for a couple of weeks she went in villages around for seeking some new materials for growth trial.
The sunlight was very hard, and made me a little sick since that on the wooden platform there was no shade where to have some repair.

New smaller platform with shade for repair (credits: Nicole Pelusio).

 In the late afternoon the big platform was finally removed for not affecting the water conditions in the cages, and another one shaded was tight to an anchor 20-50 meters away from the experiment site.

 After the last feeding session, Michael (another young feeder/mortality collector that join us often) and Felix let me trying paddling the traditional long canoe back to the shore…I was pretty bad in directing, since I was able only to drive it making circular movements! Then they helped me and finally I learned how to get it! As first paddling in Africa it was very funny and pleasant…Once arrived to the shore the new tools for feed-intake better were ready in the office for the following day.

Michael on  mahogany canoe (credits: Nicole Pelusio).

Day 14- Visit on platform and Turkish barbecue.

Visit on platform: (from left to right) Immanuel, Pierre, Felix, Nicole, Emilie (credits: Francis Murray).

Today I and Felix were doing the daily routine whilst Emilie brought within herself some people visiting our platform on board: Mr Francis and phD student Pierre from university of Stirling and the Ghanaian researcher Immanuel. 
Pierre and Mr Francis (credits: Francis Murray).

They came to visit the tilapia farm site and observing our daily routine until the end of the afternoon. Then Mr Francis gave us some advices for improving our data collection and daily tasks for the following period. After a lovely and quite chat together at my accommodation near to the farm our visitors had to leave. In the evening, Turkish neighbors invited me and Emilie for joining them for a lovely a relaxing barbecue in their house chatting together.

Felix feeding on cages (credits: Emilie Devic).

Day 13- The start of feeding the diets.

Facing to cages during feeding (credits: Emilie Devic).

  I, the feeder Felix and Emilie started to feed the fish with the 4 diets on demand during several daily feeding sessions. As first method for recording feed-intake we weighed the feed supplies in each cage at each meal. Because of the instability of platform (caused by wind and waves) affecting the scale for weighting feed supplies we need to check a new methodology of recording feed intake with a supervisor from University of Stirling.
Feed supply recording (credits: Emilie Devic).

In the late afternoon the shape of clouds faded away showing only a grey sky: the rain started to fall hardly but fortunately we reached the shore and some repair before coming back home. 

Emilie and Felix checking fish appetite behaviour (credits: Nicole Pelusio). 

Day 12- First fish weight sampling and aim of the project.

Sampling team working on platform (credits: Nicole Pelusio).

Today we sampled fish for one month growth trial in a commercial tilapia farm located on Volta Lake. 
The purpose of this trial is to compare the effects on growth performance rates on juvenile tilapia (Oreochromis niloticus) in cages on different rates of replacement of fish meal with Black Soldier Fly (Hermetia illucens) larval meal within the commercial diet of the fish. 

Tilapia (Oreochromis niloticus) juveniles (credits: Emilie Devic).

Because fish meal and fish oils are an increasingly expensive and unsustainable source of proteins for commercial tilapia feeds. Since this feed ingredient is taken from wild stocks, the continuing spread of aquaculture is pressing too much the demand, making its price raising and impoverishing the oceans. 
Moreover, there is still very little in the literature about comparing such feeds in tilapia culture in SS Africa or elsewhere.
With this trial we also want to   determine the economic viability of replacing certain percentage of fish meal with BSF meal in commercial tilapia feeds in Ghana.
Always concerning environmental sustainability, the dried BSF larval meal can be produced by recycling low value organic waste substrates (such as agriculture wastes and manure) into higher value protein sources through BSF production, with very low polluting impact (for example BSF production releases very low gases in the environment).

The trial consists of testing 4 different treatments (TO, T1, T2, T3): the control (T0) is a commercial diet used in commercial tilapia farms in Ghana. Those diets are supplied on demand for one month on 12 floating cages (1mt*1mt*1mt), where 6 gr tilapia juveniles are stocked in each.

The wooden platform (credits: Emilie Devic).


 In the morning a big wooden platform was pulled up next to the cages where the fish had fasted for at least 12 hours.

Fishing with bucket (credits Emilie Devic),

Tilapias were  netted out with a bucket, then counted in plastic baskets, dried the baskets, weighed them on a digital scales and recorded the number of fish and weight for gaining a weight average.

Counting tilapias in baskets (credits: Emilie Devic).

After sampling fish were put in few seconds in salted bath (30%) for avoiding pathogens spread after handling stress, and finally moved to each experimental cage.

Weighting dry basket with tilapias inside (credits: Nicole Pelusio).

Basket with counted and weighted fish going inside the cage after salt bath in a bowl (credits: Nicole Pelusio).

After sampling all the cages were properly labeled properly, recovered with anti-predators net and a shade for reduce stress.   
Labeling of cages (credits: Emilie Devic).

Anti-predators bed-net (credits: Emilie Devic).

Putting shading net (credits:Emilie Devic).
Cages sampled, labeled and covered after testing (credits: Emilie Devic).

The sampling started around 7,30 am and finished at 15,30 pm. In counting and fishing we were helped by a trained team of fish-farm led by supervisors Albert and Jemimah, whilst I and Emilie recorded the data. 

Sampling team in breack time waiting next samples (credits: Emilie Devic).