Management of fish production

Study Circle

2. Aim & objective
Introduction
How to do
Factor related to fishery
Fishery management
Fish recruitment
Advantages
Contents…

3. Aims and objectives
Sets out the scope,
duration and objectives of
the plan and also how it
relates to other plans .
Should set out aims and
objectives for fish species
other than trout, salmon
and other commercially
important species.

4. What is Fisheries Management?
The basic principle is simple:
Provide fish that can be caught by those with a
legitimate right to catch them.
When considering natural fish stocks this means
providing an exploitable excess of fish above the
biological limit of the population.
If exploitation/mortality exceeds the natural
biological limit, the stock of fish will decline and the
fishery will become rapidly unsustainable

5. How do you do it ?
To effectively produce sustainable levels of
catchable fish from a population one needs to
fully understand:
Species involved - spawning requirements
/escapement
Size and age structure of the population
Factors effecting the population – recruitment,
dispersal, mortality, disease, predation etc
How the target species interacts with other fish
species

6. Other factors the related to Fishery
Management :
Factors effecting the habitat in which the fish are
living:
Physical and chemical properties of the water body –
still waters and flowing waters
Productivity and its measurement
Energy flow / food webs – who eats who
Fish feeding requirements / limitations
Levels of predation and mortality

7. Toolbox approach
Improve habitat .
Improve in-stream structures.
Maintain acceptable water quality .
Maintain/improve access for migratory fish.
Control poaching activities/control predation.
Alter recruitment to the population.
Influence surrounding land management
practices.
Consider stocking .

8. What is required?
Nets with bigger mesh size
Regulated fishing methods
More data on fish populations (e.g. by fish tagging
investigations – mark and recapture)
Constant monitoring to observe changes in
environmental factors (e.g.El Niño events
Policing of fishing industry – respect of quotas
International agreements
Greater exploitation of fish farming
But this is not without its own problems (space, diseases
and pollution are all associated with intensive fish culture)
© 2008 Paul Billiet ODWS

9. Fish stocks
Though fish farming is increasing, fishing represents the
last major exploitation of wild populations by mankind
ACEL
Factory ship

10. Fishery Management Plans
Need framework to give consistency of plan
production.
Based on best scientific evidence available.
Framework must be flexible enough to cover all
species and regions.
Formalised thought process that develops
management actions from data.
Cyclical process which evolves, both driven by
research and identifying further research needs.

11. Fisheries by Their Nature are Extractive;
They Alter the Natural Environment
anthropogenic
effect

12. Fish Recruitment
 Recruits are fish at harvestable age/size
Reproductive
Adults
Juveniles
Eggs/Larvae
Immature Adults
Harvestable
Size/Age
H
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Recruitment

13. Advantages
Encourages a strategic view of management.
Prioritises issues and works required.
Identifies needs for resources and finance.
Gives continuity of management- staff / management
changes.
Proactive rather than reactive management.

14. More Advantages
All stakeholders can see and understand the reasons
for management actions and the research and analysis
supporting them.
Management and research linked in an evolving
process.
Linkage with wider catchment and basin planning
process.
Funding opportunities

15. What is causing the damage to fisheries
worldwide?
Uncontrolled harvesting – even if quotas are imposed
they need to be policed
Unrealistic and inflexible quotas
Insufficient data on fish populations
Improved technology in the fishing industry

16. Monitoring and review
This ensures that the plan achieves the objectives
detailed in the first section and is also sufficiently
flexible to adapt to changing circumstances and new
data.
This is likely to take place annually or at key
milestones in the implementation of the plan.

17. Analysis-water quality and quantity
Electro-fishing found four year classes of brown trout
present, indicating that both water quality and
quantity were suitable for salmonids.
There is no compensation flow agreed for
Glascarnoch. The present flow is due to leakage from
the dam and surface run off from surrounding land.

18. Application of Management Plan process
This example is from a fishery management
project with the aim of sustaining salmon stocks.
The same decision making process applies equally
well to managing hill loch brown trout and char,
protecting lamprey habitat or monitoring the
status of eels.
In many cases where little information exists, the
first phase of a plan will be to set out a
programme to collect the data which will be
needed for future management decisions.

19. Quiz ? ? ?Quiz ? ? ?
Rank of India in fish production ?
Why sex hormones are used in feed for fishes ?
Total fish population in India ?
Largest fish production area of India ?
Most popular fish breed in India ?