The spots that consistently produce grayling in late October are not the same spots that produce them in early April when the snowmelt has the current running at twice its summer speed. You know this from memory after enough years on the same watershed. But memory erodes, and the guy who told you about the bend below the spruce stand — the one where he pulled a 2.1kg pike on a jig in -12°C — is not always available to remind you.
Location as Persistent Data
The Coordinate field converts every fishing spot from a vague verbal description into a GPS-anchored record. "The creek mouth where it feeds into the bay" becomes a specific coordinate that navigates you back to within 10 meters of the same hole, even if you haven't fished it in two years and the bank looks different after winter flooding changed the shoreline.
The Place field takes a free-text name — "Spruce Bend," "The Old Bridge Piles," "Navaga Hole km 4" — that gives the location a conversational reference separate from the coordinate. When you're talking to another angler about where you found burbot running, you exchange place names, not GPS strings.
The Species List Tells You the Fishery
Seventeen species — Navaga, Pike, Perch, Whitefish, Grayling, Smelt, Ide, Flounder, Salmon trout, Trout, Salmon, Bream, Ruff, Crucian, Herring, Burbot — map to the typical fish population of the northern Russian freshwater and coastal ecosystem. This is not a generic freshwater list. Navaga is a cod-family fish found in Arctic coastal waters. Burbot is the only truly freshwater cod, found in cold Siberian and subarctic rivers. The species list defines where this logbook was built and who built it.
Filtering all records by Fish = Grayling over a two-year period produces a map of the productive grayling locations, the dates they were productive, and — combined with Weather notes — which weather conditions correlated with active feeding. That's the database value: not the single catch record, but the pattern that only becomes visible across fifty records.
What the Contact Field Captures
The Contact field tracks the source of information entries — a catch you made yourself, or a report from a friend who fished the upper reach on Tuesday. The logbook description explicitly states it's "for keeping notes on the basis of own catches and on the stories of friends." A contact-attributed entry for a location you haven't personally visited is still valid data when the source is reliable. It's scouting intelligence.
The distinction matters when you're analyzing your records later: your own direct experience versus secondhand reports should be weighted differently, and the contact attribution field makes that distinction explicit rather than leaving it to a cryptic note in the comments that you may or may not remember writing.
Weather, season, and location are the three variables that experienced anglers manipulate. The logbook captures all three.