Lab
Fish Identification Basics
Fish identification is a nuanced task that takes into account both on-fish identifiers and the surrounding environment. Spatial and temporal factors are often overlooked by beginners, but they are equally important to successful identify fish species as fish characteristics or anatomy. For example, some fish migrate to spawn or have certain temperature restrictions. Thus, you are very unlikely to find a warm-water species in a high mountain lake or an anadromous (lives as an adult in the ocean- migrates to fresh water to spawn) in freshwater outside of spawning season.
Once you have a basic understanding of the environment you are working in and a general idea about which types of fish you may see there, it is possible to use key characteristics to determine the species of a fish. Below are some important terms and anatomical features of fish that are critical to know for fish ID.
Posterior
Anterior
Ventral
Dorsal
Lateral
1. Fish directions:
Knox Pond Fish Characteristics
The spatial and temporal elements of fish identification are artificial in Knox Pond, as it has been stocked. Below are the species believed to be in Knox Pond. Some of these fish look very similar, but they all have key features that make them unique.
- Small mouth relative to body
- Upper jaw reaches to the posterior edge of eye
-Operculum flap is usually dark
-Pectoral fins are long and will reach past the eye when folded forward.
- Vertical banding may be present on lateral sides of fish
-Small mouth relative to body
- Upper jaw extends to the center of eye
-Pectoral fins are relatively short and will not extend to the eye when bent forward
-Operculum flap is large and often outlined in white, teal or red.
-Relatively large mouth compare to body
-Lower jaw extends to middle of the eye
-Pectoral fins are short and rounded
-Pectoral fins will not reach beyond the eye when folded forward
-Often have a blunt stout anterior
- Scales are larger anteriorly than posteriorly
-Average length is between 1.5-3inches as adults but they can grow to 4inches.
-Often mottled in color
- Tail is slightly notched, but not forked
- Compressed head
6. Largemouth Bass ( Micropterus salmoides): MISA-NATIVE
-When mouth is closed, the upper jaw extends well beyond the eye
-Deep notch between the soft and spiny dorsal fins
7. Goldfish ( Carassius auratus): CAAU-NONATIVE
- Looks like other flathead catfish, but has a deeply forked tail
-Compressed head
- Stout body
-Tail is rounded or nearly straight with no fork.
-Chin barbels (whiskers) are yellow or white
- Stout body
-Tail is rounded or nearly straight with no fork.
-Chin barbels (whiskers) are dark brown or black
- Large mouth relative to body
-Upper jaw extends under the eye and lower jaw protrudes forward
-Depression in its forehead
-Large forehead
-Dorsal and anal fins are almost the same size
- May be orange, silver, white or combination of these colors.
-Mouth points up
- Tail is rounded
-Very small
-Belly may appear to be bulging
Taking Fish Metrics
As a good rule of thumb, always keep equipment (hands, fish measuring boards etc.…) wet to prevent harm to the fish. Do not hold fish outside of water for extended periods.
1. Equipment
Fish Measuring Board
2. Fish Measurements
3. Sample Data Sheets
|
Species (use first two letters of genus and first two letters of species) |
Total Length (Only measure this on native species that are returning to the pond) |
Weight in grams. (Tare the scale with the Tupperware on top to place the fish in) |
Comments (note any injuries, deaths, deformities etc...) |
|
LEMA |
130mm |
25 |
|
|
CACU |
|
|
Mortality |
|
GAAF |
38mm |
2 |
|