Fish Biology (WSJCANC)


Participants will learn how Arkansas Game and Fish Commission (AGFC) fisheries biologists use fishes’ anatomical information to manage populations. Participants will identify internal and external parts of fish and learn how fish are aged from scales and otoliths.

Grade Level:

Grades 4 - 8, Grades 9 - 12

Recommended Setting:

Indoor or outdoor classroom

Outdoor Activity:



Witt Stephens Junior Central Arkansas Nature Center, Little Rock


Education Coordinator, 501-907-0636


45 - 60 minutes

Suggested Number of Participants:

10 - 30


  • Learn the major external and internal parts of fish.
  • Distinguish between fish and human anatomy.
  • Realize how fisheries biologists study fish anatomy to manage fish populations.
  • Examine fish scales and otoliths and understand how biologists collect them to age fish.

Key Terms*:

Arkansas Game and Fish Commission (AGFC)

Amendment 75 of 1996

Central Arkansas Nature Center (CANC)

Fins (spiny dorsal, soft dorsal, caudal, anal, adipose, pelvic, pectoral)

Fisheries biologist

Fisheries management


Lateral line





Swim bladder


*See glossary for definations


Assortment of otoliths and scales in vials

Dissected fish model

Graph paper for otolith aging activity (9 - 12 only)

Internal and external anatomy sheets

Power Point of AGFC biologists collecting data from body parts of fish (scales, otoliths, fins, etc.)

Slides of magnified otolith photos

Optional: scales and otoliths overhead transparencies (9 - 12 only)


Arkansas has a diverse ichthyofauna with more than 200 species of fish, which biologists manage using several techniques. The agency’s 25 biologists work directly with fisheries management


  1. Introduce yourself and the CANC. Explain that it is owned and operated by AGFC and showcases the agency’s mission. Also tell how Amendment 75 of 1996 funds paid for the facility and allow free admission.
  2. Explain that AGFC fisheries biologists manage by a thorough understanding of each fish species. Explain that training in fisheries management involves a minimum four-year biology degree and that most AGFC biologists have master’s degrees plus additional education.
  3. Distribute the anatomy sheets and use the projection screen to outline external and internal body parts of fish, and have participants write the anatomical names on their sheets. Briefly outline the function of the body parts. Have the participants identify parts of fish that humans do not have (scales, fins, lateral line, gills, swim bladder) and some that humans have that fish do not (arms and legs, hair, lungs, ears, noses, etc.) Optional: Use a dissected fish model to show the actual internal and external parts.
  4. Transition to the Power Point that shows AGFC fisheries biologists collecting scales, otoliths and fins and explain that fisheries management must be based on facts from fish species. Participants should complete their Power Point question sheets during the presentation.
  5. After the Power Point, distribute vials of otoliths and scales to show the different sizes and shapes among species. Note that biologists prefer otoliths because they offer more reliable data. Otoliths are used to determine 1) growth rates 2) mortality rates and 3) age and size at sexual maturity.
  6. (9 - 12 only) Have the participants view scales and otoliths under microscopes (or use a projection microscope to place images on the screen) after explaining how biologists age fish from these body parts. They can do this in groups as the vials are distributed.
  7. After all have used the microscopes to see how to age fish from scales and otoliths, distribute otoliths in vials marked by age. Tell participants to assemble them by age into groups. Once they have done that, have them count how many otolith vials are in each group and graph on the paper provided.


  • Investigate Arkansas fish species based on anatomical differences. For example, how many species have no scales? Which fish is identified by its unusual protruding “nose?” How many fish can they name that have barbels? (“Fishes of Arkansas” is the resource on Arkansas fish species. Use it to compile these types of questions about Arkansas fish, and then refer participants to it for the answers.)
  • (9 - 12): Distribute copies of the “Do Fish Feel Pain?” study by Dr. James Rose of the University of Wyoming. Use the question sheet provided to have a class discussion of differences between animals (in this case, fish) and humans.


  • Why is it important for AGFC biologists to keep up with the age of fish in a lake or river? (They use this information to track populations and ensure they remain healthy.)
  • Why must biologists collect ongoing age data from the same lakes and rivers? (They can monitor fish species populations over time to make the best management decisions rather than on limited information.)
  • What would fisheries biologists do if they learned that not enough of a certain fish species was living long enough based on the data they collect? (They could change some management methods or recommend regulation changes.)
  • What is the difference between fish gills and human or mammalian lungs? (Gills extract oxygen from the water for fish to breathe; lungs take oxygen from the air.)

Participant Information Sheets:

"Do Fish Feel Pain?”

Participant Worksheets:

• “Do Fish Feel Pain?”
• Fish anatomy


Adipose fin – small fleshy fins located behind the dorsal fin on the back of some species


Anal fin – the fin behind the anus on the bottom edge of fish; used to maintain balance


Arkansas Game and Fish Commission (AGFC) – the state agency responsible for managing fish and wildlife


Caudal fin – the tail fin of a fish; used to generate forward movement


Fisheries biologist – a scientist who studies and manages wild fish populations


Fisheries management – the scientific guidelines and procedures used by fisheries biologists to accurately provide for healthy fish populations


Gills – organs located behind the cheek on the head of a fish that remove oxygen from the water for respiration


Lateral line – a horizontal row of scales on most fish that contain sensory tubes that detect vibration in the water; used to locate food, other fish and potential dangers


Nares – nostrils in the snout of fish used to detect scents


Operculum – the protective, bony flap that covers the gill of most fish


Otoliths – three structures within each inner ear of bony fish that detect sound and gravitational forces; fisheries biologists can age fish by counting the annual growth rings found on otoliths


Pectoral fin – the fin behind each gill of most fish; used to stay stationary and to dive or surface


Pelvic fin – the fin on each side of the belly of most fish; used for positioning and balance


Scales – the exterior covering of most fish that protects from injury and disease; scales increase in size as the fish does, and show annual growth rings


Soft dorsal fin – a soft-rayed vertical fin on the top of most fish; used to maintain balance and move in tight spaces


Spiny dorsal fin – a hard-rayed vertical fin on the top of many fish; used for defense against predators, to maintain balance and move in tight spaces


Swim bladder – an airtight sac in the body cavity of most fish used to suspend in the water


Vent – the opening on the lower side of a fish used to expel waste