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).

Fig: Coded wire tag in nose of fish.

Chemicals

Alizarin (ALC)  Calcein Oxytetracycline (OTC)

Physical Methods

Internal• Body Cavity tags• Subcutaneous tags• Coded Wire tags• Micro tags• Passive Integrated

Transponder tags (PIT) • Thermal Tags• Radio tags• Sonar tags

External• Mutilation• Branding• Visible Implant Elastomer

(VIE)• Petersen disc• Paper fastener• Strap tag• Dangler tag• Carlin tag• Spaghetti tag• Dart tags• Anchor tag

External attachment

Internal attachment

Recommendations

National and international courses on tagging procedures are recommended.

Simple and cheap ID tags are recommended . Choice of tag or mark type should be made after a

cost-benefit analysis. Programs involving electronic tags should be

incorporated with fish tagged. Further development of existing tag types.

Conclusion:

Fish marking and tagging is a fundamental tool for fisheries management and research. It allows biologists to gather a wide variety of information.