Fishing · 9 min
Fish identification and behaviour
Why this matters
'Fish identification' is a named exam subject, and it is also a legal skill: seasons and limits are species-specific, so misidentifying a fish is how a client ends up with a violation. Behaviour is what makes you worth hiring.
By the end of this lesson you will be able to
- Identify New York's principal gamefish by their diagnostic features
- Separate the confusable pairs: brook and brown, pike and pickerel, the black basses
- Explain temperature, structure and season as the drivers of fish location
The trout and salmon
| Species | Tell it by |
|---|---|
| Brook trout (the State fish, a char) | Light spots on a dark background, worm-like squiggles (vermiculation) on the back and dorsal fin, red spots with blue halos, and white leading edges on the lower fins. Square tail |
| Brown trout | Dark spots on a light background, many with pale halos, some rusty red. Few or no spots on the tail. Square-ish tail |
| Rainbow trout (steelhead when lake-run) | A pink or red lateral stripe, small black spots scattered over the body and radiating across the tail |
| Lake trout (a char) | Light spots on dark, like a brook trout, but no vermiculation and a deeply forked tail |
| Landlocked Atlantic salmon | Confusable with brown trout. Spots are more x-shaped, the tail is more forked, the body more slender, and the upper jaw ends about level with the back of the eye rather than well behind it |
The one-line rule: light spots on a dark body means a char (brook or lake trout); dark spots on a light body means a trout or salmon.
The bass
| Largemouth | Smallmouth | |
|---|---|---|
| Jaw | Upper jaw extends past the rear of the eye | Upper jaw ends at or before the rear of the eye |
| Markings | A dark horizontal band along the side | Dark vertical bars, bronze cast |
| Dorsal fin | Nearly separated into two | Clearly joined |
| Habitat | Weeds, wood, warm shallow bays | Rock, gravel, current, cooler clear water |
The pikes
| Species | Pattern | Cheek and gill cover |
|---|---|---|
| Northern pike | Light bean-shaped spots on a dark green body | Cheek fully scaled, lower half of gill cover scaleless |
| Muskellunge | Dark bars or spots on a light body, the reverse of a pike | Lower halves of both cheek and gill cover scaleless |
| Chain pickerel | A distinct chain-link pattern, and a dark vertical bar under the eye | Both cheek and gill cover fully scaled |
The scale pattern is the reliable field key when colour is ambiguous. Also useful: pike have five or fewer sensory pores under each side of the jaw, muskellunge have six to nine.
Walleye and yellow perch
Walleye: big glassy reflective eye, sharp canine teeth, and a white tip on the lower lobe of the tail, which separates it from the much rarer sauger. Yellow perch: golden with six to eight dark vertical bars and orange lower fins. Both feed low-light, which is when you take clients out for them.
Behaviour, in three drivers
- Temperature. Every species has a preferred band: brook trout are cold-water fish and will not hold in warm water at all; largemouth bass want warmth. In summer, coldwater fish go deep or to spring holes and tributary mouths. This is why a July trout trip means small headwater streams or deep lakes
- Structure and edges. Fish hold where something changes: a drop-off, a weed line, a rock pile, a current seam, a shadow line, an inlet. Featureless water holds few fish. Teach clients to fish edges and they will catch fish without you
- Light and season. Dawn and dusk are the general answer, more so in bright clear conditions. Spawning moves fish predictably: bass to shallow gravel in late spring, trout to gravel in autumn (brook and brown) or spring (rainbow)
From the field
A client lands a pike-shaped fish and wants to keep it. You check the cheek and gill cover: both fully scaled, and a clear chain pattern. It is a chain pickerel, not a pike or a musky, which are different seasons and different limits. Being able to say that in five seconds is the job.
This lesson is part of the NYS Licensed Guide Exam course. Open it in the course to answer the retrieval checks that go with it, track what you have read, and quiz the whole unit. Lessons, quizzes and the glossary are free.