Tagging Methods For Stock Assessment and Research In Fisheries Submitted To: Md. Nurunnabi Mondal Assistant professor, Dept. of Fisheries Management Faculty of Fisheries. Submitted By: Nazmul Ahmed Oli Reg. no:12-05-2835 Level: IV Term: Autumn’15 Course Title: Fish population Dynamics Course Code: FMG- 431
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Tagging methods for stock assessment and research in fisheries
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Tagging Methods For Stock Assessment and Research In Fisheries
Submitted To:Md. Nurunnabi MondalAssistant professor,Dept. of Fisheries ManagementFaculty of Fisheries.
Submitted By:Nazmul Ahmed OliReg. no:12-05-2835Level: IVTerm: Autumn’15Course Title: Fish population DynamicsCourse Code: FMG-431
Introduction:
Systematic tagging of fish for scientific purposes has been conducted for more than a century.
When it was started, it represented an exciting methodology for obtaining fundamentally new information about fish migration and movements as well as on the dynamics of exploited fish population.
OBJECTIVES
To assess the past, present and future about use of tags
To assess reliability of tagging methods with emphasis on their application in fisheries research and stock assessment
To facilitate improvements in tagging
methodology and application
Planning of Tagging Programs
A careful assessment of the objectives, relating them to a cost/benefit analysis is useful
One should check the local tag recovery and refunding system
Handling time for each fish needs to be short.
TAG AND MARK TYPES
Advantages• Inexpensive, or simple• Easy and fast to apply• Useable for a large range of
fish sizes • Can give a broad geographical
and seasonal return distribution• Long tag-retention time
Disadvantages• Information may be variable.• Return rates may be variable.• Fouling of the tags may be a
problem.• May affect behavior and
swimming• Can be difficult to apply or may
not be applicable to very small fish
External tags
• Inexpensive and usually rapid to apply
• Ideal for identification
• Suitable for a range of sizes
• May have long duration, depending on the type
• Applicable to large numbers of fish
Adva
ntag
esVisible on the outside of the fish and
employed to identify individual fish or groups of fish
• Limited number of codes or combinations
• Recognition errors
• Marks may deteriorate with time
Dis
adva
ntag
es
External marks
Advantages• Little or no effect on growth, health and survival • suitable for a wide range of sizes and many species of fish • High retention rates.• Individual recognition of fish is possible • Repetitive and non-destructive recoveries are feasible
Internal Tags:
Disadvantages• Expensive equipment • Expert personnel are needed • Recovery of specimens of fish may be labor-intensive
Advantages• Minimal immediate effects
from handling and marking• Effects on behavior, growth,
health and survival of fish are minimal
• No extra marking or additional handling is needed.
• Distinct growth patterns
Internal marksMarks not visible from the outside of
the fish.
Disadvantages• Recovery usually requires • Expensive• Expert personnel and
specialized laboratory facilities
• Difficult to apply to natural populations
Methods
Parasitic Marks- Used to identify stocked fish and determining movement or migration patterns.
Morphological Marks- Used to differentiate stocked fish and for mark recapture studies.
Genetic Marks- Used to identify fish stock.
Biological (Natural Methods)
Chemical (immersion, injecting, tattooing, or feeding)
Immersion Injection Feeding
Fig: Image of a thermally marked otolith with a pattern of five dark bands (near center).