Does the protein and temperature influence growth performance of slow and fast growing Meagre?
INTRODUCTION
The location
The research facility is located near Olhão in the Algarve region of Portugal. It is situated in the Ria Formosa national marine park which boasts an incredible diversity of marine life and functions as a nursery for some migrating species.
The facility
The station, a satellite facility of IPMA (Portuguese Institute for Sea and Atmosphere) is a fish and aquaculture research facility which focuses on improving health and yield of important commercial fish species in this region. It houses both indoor tanks and outdoor earthen ponds. The fish used in the trials are either hatched from brood-stock in the facility or fished from the surrounding sea. Surpluses after an experiment are sometimes tagged and released back into the Ria.
Most common species at the facility:
Sea bream (Sparus aurata)
Meagre (Argyrosomus regius)
Senegalese Sole (Solea senegalensis)
Sardines (Sardina pilchardus)
Sea urchins (Paracentrotuslividus )
Juvenile meages (Argyrosomus regius)
Grouper (Epinephelus marginatus)
THE PROJECT
My project consisted of taking care of 6, 300L tanks, each containing 1050 juvenile meagre. I would clean their tanks multiple times a day and make sure they were healthy.
The tanks were split into 2 groups, one group had its water temperature at 20°C while the other was kept at 24°C.
Water from the tanks is pumped from the sea and is prone to daily temperature fluctuations, measurements and corrections to the water temperature has to be done multiple times a day.
I performed biometric sampling (weight and size measurements) 4 times during the 7 week trial period. I noticed an increase in growth in all tanks, with a clear difference between the two groups.
My daily duties consisted of cleaning the tanks, making sure the fish were healthy and at the correct water temperature
The setup
We see here one of the tanks at 20°C, the fish get stressed when you stand above their tank and will try to escape.
We had to place nets encapsulating each tank to stop them from killing themselves when jumping to escape.
At this stage the fish were 4.5 cm long on average in these tanks, the larger ones were able to leap out without the net.
My batch of 6 tanks with early stage juveniles
Project goal
Our research questions:
Does a higher temperature promote higher size and weight dispersion for juvenile Meagre?
Can fast growing fish from lower temperature tanks reach the size and weight of slow growing fish from the higher temperature tanks?
Our objective:
To understand the influence of temperature on growth rate of a commercial fish species, Argyrosomus regius and how it affects the genetic expression of the fish for insulin growth factor-1.
The worse scenario we came across, it did not however affect the project
Project mishaps
Working with live animals, I would have been surprised if nothing had gone wrong.
One night, an automatic feeder had gotten stuck and released all its food in the tank, by morning the ammonia levels were too high and began poisoning the fish. by the time I arrived at the facility the death count was 475.
Afterwards, all feeders were removed and the fish were hand fed every 40 minutes till the end of the work day.
PERSONAL ACHIEVEMENTS
Measuring and weighing the fish to compare between tanks and previous samplings
My contributions
During my stay at the facility I spent my time:
Raising the fish for 7 weeks
Keeping them healthy (washing tanks, feeding them, cleaning their filters)
Sampling biometry, genetic and fatty acid data
Compiling the data into multiple excel sheets
Helping other research groups with their projects
Assisting in the lab
A medium sized specimen from my tanks, species Argyrosomus regius
The first picture is the result of a qPCR test, the second is my sampling transcribed on an excel file
What I gained
Research skills:
Learning how to care for fish, (husbandry, rearing early juveniles)
Performing a qPCR analysis
Using new lab equipment
Aiding in basic lab work (dissections, data sampling)
Social skills:
Being adaptable in a new environment, working in a country where I do not speak the language
Being independent in managing my project
Managing my hours within the day to cater to the fish
Developing my team work skills
Both pictures show qPCR preparation work
PRELIMINARY RESULTS: WEIGHT DISTRIBUTION
X axis shows the weight of fish while Y axis shows the frequency
graphs are placed chronologically
weight distribution 12/05/21
weight distribution 20/05/21
weight distribution 26/05/21
weight distribution 31/05/21
Over a period of 20 days, we see an increasing difference between the fish in the hotter and colder tank.
The weight and size dispersions are increased in the hotter tanks compared to the colder tanks.
The fish in the hotter tanks have increased growth rates, higher temperatures correlate with an increase metabolic rate and so too, with food consumption.
The same can be said for size growth, the fish in higher temperature water grow faster and to a larger size.
Size distribution graphs with size in cm on the x axis and frequency of number of fish on the y axis
CONCLUSION
Entering the facility, you are always greeted by incredibly curious Epinephelus marginatus, who spit on you if you don't give them food
Participating in this trial made me aware of the amount of work that needed to be done for a few pieces of data as well as the resources necessary to carry out aquaculture research.
I realised that working with live animals is both enjoyable and terrifying, like my supervisor said. "something will always go wrong in your experiment, especially with live specimens".
Overall, I learned many new things at the facility and I would recommend it to other students. I was disappointed that I did not have the time to complete the data analysis part of the research, but It was an amazing placement for a professional practice nonetheless.
A view from some of the inside tanks, showing the labyrinth of water pipes that feed the facility
special thanks to everyone at EPPO IPMA !
Professional Practice summer 2021
Yliam Treherne 2020 cohort
yliam.treherne@imbrsea.eu