Trocino Lecture 2

Question 1

What is Fisheries?

Answer 1

• activity performed by humans to obtain goods from the aquatic environment
• to support their existence without actively acting on the natural production processes

Question 2

What is Aquaculture?

Answer 2

• farming of aquatic organisms
• to obtain a quantity of a product higher than what the environment could provide naturally
• using partial or complete control of their biological cycle and environmental factors

Question 3

What are the main objectives of Aquaculture?

Answer 3

• economic gains (income)
• societal benefits (increased animal protein for nutritional purposes, employment)
• environmental conservation (e.g., maintaining lagoon ecosystems)

Question 4

What is the difference between Fisheries and Aquaculture?

Answer 4

Fisheries involve the collection of aquatic goods from an open environment without active intervention

Aquaculture involves the collection of goods from a controlled, bordered environment with active intervention in the production processes

Question 5

What is a stable/ unstable aquatic ecosystem?

Answer 5

Question 6

Define Fish stock

Answer 6

• a population of fish that is part of an ecosystem
• interacting with other animal and plant species
• the population size and structure can change due to natural factors and fishing activities
• fishing can alter the age and size distribution of the fish, impacting the overall health and balance of the ecosystem

Question 7

What is Total Allowable Catch (TAC)?

Answer 7

• TAC is the maximum amount of a particular fish species that can be taken by commercial fishers during a fishing period
• as determined by fishery managers to prevent overfishing

Question 8

What is Total Allowable Fishing Effort (TAE)?

Answer 8

• TAE is the maximum level of fishing effort that can be applied to a fish stock during a specific period
• usually expressed in terms of limits on the number of fishing days and/or operating vessels
• Often used in the Mediterranean and other regions
• TAC limits the quantity of fish that can be caught, while TAE limits the amount of effort used to catch fish

Question 9

Differences between TAC and TAE?

Answer 9

Question 10

Which control in Aquaculture?

Answer 10

1. Seeding

• Introduction of young fish or larvae into the aquaculture system.
• Methods: natural migration, collection from the wild, or seed production in hatcheries.

2. organization of fish population

• Managing the quantity, species, sizes, and associations of fish.
• Separating species to prevent competition or predation.

3. Standardization of the Production Cycle:

• Defining and controlling the stages and duration of the production cycle.
• Ensuring consistent and optimal growth and health of the fish.

4. Monitoring and Controlling Water Quality:

• Maintaining optimal water quality parameters such as temperature, oxygen levels, pH, ammonia, and nitrite concentrations.
• Regular testing and adjustments to maintain a healthy environment.

5. Monitoring and Care of farmed organisms
6. Feeding

• Ensuring fish receive the right amount and type of food.
• Minimizing waste to prevent water quality degradation.

7. Capture and Harvesting:

• Harvesting fish when they reach the desired size and quality.
• Ensuring humane and efficient methods to minimize stress and maintain product quality.

Question 11

What and how much can we control in aquaculture?

Answer 11

Question 12

biotic/ abiotic factors in aquaculture

Answer 12

Question 13

What is Stocking Density in Aquaculture?

Answer 13

Stocking density is the ratio of biomass of farmed organisms (kg, ton) per water surface or volume (m², m³), indicating the concentration of fish in a given area.

e.g. [kg/m²]

Question 14

What is Vital Space in Aquaculture?

Answer 14

• refers to the minimum fraction of a niche within a habitat occupied by a single specimen or a group of specimens of the same species
• determined by both fixed and variable factors

Question 15

Vital space under farming conditions

Answer 15

can be reduced by the administration of feed (Verabreichung von Futter) as long as all other factors that contribute to the definition of vital space are kept at a suitable level

Question 17

calculation vital space?

Answer 17

Question 18

calculation stocking density?

Answer 18

Stocking Density = 1/VS

VS = vital space

Question 19

what limits the Vital Space?

Answer 19

It is affected by different fixed factors which act together, for which:

VS = max (K1/F1 , K2/F2, … , Kn/Fn)

Thus, vital space will be determined by the most limiting variable factor

Question 20

Does stocking density alone determine the intensity of production in aquaculture?

Answer 20

No, stocking density alone does not determine the intensity of production. The origin of feed is a crucial criterion to distinguish between extensive and intensive farming systems.

Question 21

What is an extensive aquaculture production system?

Answer 21

• involves only the control of fish movement
• to facilitate capture operations without significant control over other environmental factors

Question 22

What is a semi-intensive aquaculture production system?

Answer 22

involves more control over environmental factors like water

• basins
• tanks
• feeding
• water quality

but not as much as in intensive systems.

Question 23

What is an intensive aquaculture production system?

Answer 23

involves simultaneous control of

• reproduction
• environment
• feeding

for ensuring high productivity and efficiency.

Question 24

What are some differences between farming terrestrial vertebrates and aquatic organisms?

Answer 24

Key differences include the

• aquatic environment
• the variety of species that can be farmed
• feeding in water
• fertilization in water
• the variety of systems/environments
• different problems for different species like tuna, octopus, and eels

Question 25

What factors distinguish extensive, semi-intensive, and intensive aquaculture production systems?

Answer 25

• Extensive systems focus on controlling fish movement
• semi-intensive systems control environmental factors to a moderate extent
• intensive systems control reproduction, environment, and feeding comprehensively.

Question 26

Classification of Aquaculture Systems

Answer 26