Where the data comes from

Sources

Fångstrapport.se is built on open and official sources. Nothing is scraped from commercial services.

• Lakes and municipal boundaries come from SMHI's SVAR (the Swedish Water Archive) and from Lantmäteriet's open map and administrative data. These are the same datasets that research and the public authorities use.
• The map background on every map is Lantmäteriet's topographic web map — the official Swedish terrain map, with contour lines, watercourses, paths and jetty symbols. We host it ourselves, which makes the maps independent of any outside map service. Published under Creative Commons Attribution 4.0 (CC BY 4.0) ("© Lantmäteriet").
• Rivers are built from several SVAR layers woven together: line geometries and names from SMHI SVAR Flödeslinjer, the connections between rivers and lakes from SMHI SVAR Vattenytor (which drives the "Lakes along the way" list), and the drainage basin from HaV's register of main drainage basins (HARO) (which drives the basin badge in the page header). Each SVAR segment used to be shown as a river of its own; since the rework in May 2026, segments with the same name in the same main basin are merged into a single river where they are physically connected in the SVAR graph. That turns a river like Indalsälven (531 km) into one page instead of 336.
• Named places along rivers come from SLU SERS (the Swedish electrofishing register) — sampling sites where biologists have measured fish since the 1980s. They are not recommended fishing spots, but stable names for well-known stretches such as "Härnäs" or "Forshagaforsen".
• Marine areas come from the Swedish Agency for Marine and Water Management (HaV).
• Fishing rules — minimum sizes, maximum sizes, closed seasons, catch quotas — are loaded from HaV's rule register plus the county administrative boards' own county-specific regulations.
• Fishing conservation associations (FVOF) come from the county administrative boards' open register of fishing conservation areas, plus details the associations themselves submit through the correction form.
• Depth maps come from SMHI Vattenwebb / SVAR — scanned bottom charts produced by SMHI and the county boards over the years. We provide the original files unchanged, plus a processed preview. The source material is published under Creative Commons Attribution 4.0 (CC BY 4.0) — free to download and use as long as SMHI is credited as the source.
• Species in the water — the "Species in the water" section on lake, river and sea pages is compiled from several sources: the associations' own information, catches logged on Fångstrapport, and three national scientific registers from SLU Aqua: NORS (gillnet survey fishing in lakes), SERS (electrofishing in rivers) and KUL (coastal survey fishing). From these we use which species have been seen (presence) and the largest documented lengths (see the next point) — never density or catch per unit effort. As a supplementary source we use observations from GBIF (the Global Biodiversity Information Facility), filtered to reliable record types.
• Survey fishing: documented sizes — on the leaderboards on lake and species pages we show the largest individuals that SLU Aqua's gillnet surveys (NORS) have measured per species and water, with the year. These are historical research observations from standardised nets — not angling records, and not a forecast of what you will catch. We show only the largest documented length.
• Moon, sun and sky (/moon) is computed locally from standard astronomical sources — the synodic month for the moon phase, NOAA's solar position algorithm for the sun, and Meeus chapter 47 for the position of the moon.
• Air pressure comes from SMHI's open data — the MetObs API (parameter 9, mean-sea-level reduced pressure). We fetch hourly measurements from the roughly 116 active synoptic weather stations and work out the pressure at each catch position by inverse-distance weighting from the five nearest stations. Air pressure is a smooth field at synoptic scale — it varies over hundreds of kilometres, not metres — so station interpolation sits within ±0.3 mb of SMHI's own gridded analyses. The source is stated on every page that shows the pressure; CC BY 4.0 ("Source: SMHI").
• Air temperature, wind, precipitation and solar radiation come from the same SMHI MetObs API as the air pressure — parameter 1 (air temperature, instantaneous, hourly), parameter 4 (wind speed, 10-minute mean reported hourly) and parameter 21 (maximum gust, hourly), parameter 7 (precipitation, hourly sum) and parameter 11 (global irradiance, hourly mean). The first four come from the same synoptic station network as the air pressure; the solar radiation comes from SMHI's separate solar network (17 active stations across Sweden). Each catch has these values attached when they are notable — a strong wind of 8 m/s or more, rain of 0.5 mm an hour or more, or an air temperature below zero or above 25 °C. Otherwise they are left out, to keep the data compact. CC BY 4.0 ("Source: SMHI").
• Water temperature comes from SMHI's hydrological model S-HYPE through Vattenwebb — one daily modelled value per sub-catchment since 2016. Sea temperatures near the shore come from SMHI's marine observation stations (parameter 5, sea temperature — buoys, coastal gauges and ferry-box). More on how we work out the water temperature. CC BY-SA 4.0 ("Source: SMHI").
• The character of the water — on lake and river pages we show measured properties of the water itself, where measurements exist: Secchi depth and clarity (clear, or humic and brown), nutrient status (nutrient-poor to nutrient-rich) and acidity (the lowest measured pH, and buffering). These come from SLU Miljödata MVM, the national database for water chemistry in lakes and rivers, compiled from periodic sampling (free to use, CC0; we credit SLU Miljödata MVM as the source). Where a water is limed, that is stated too; the information comes from the county boards' national liming database. These are descriptions of the water as it has been measured — periodic spot samples, not real-time values, and never a forecast about the fishing.

Known gaps

We want every lake, river, species and association to have a page, even where the details are thin. Better a page titled "Lake in Arjeplog" than no page at all. But some holes are worth being open about:

• Around 64 % of the associations lack complete contact information (website, email or telephone). Around 46 % have no direct link to permit sales.
• 14 of the 21 counties still have no county-specific rules in our register. The national rules from HaV still apply on those pages; the county-specific rules are to be imported from the county boards' own PDFs, and that work is under way.
• Gotland has no association data in the first import. Gotland has a separate permit system administered by the County Administrative Board of Gotland, and it is not in the same catalogues as the mainland associations.
• Depth maps cover 8,069 lakes — 100 % of SMHI's archive, but a fraction of the total number of lakes in Sweden. SMHI has historically scanned mainly the larger and hydrologically interesting waters; for lakes outside the archive there is no depth map from us.

None of these gaps is blocking — the pages work and are searchable. But we want them filled, and this is how you can help.

How you can help

Do you represent a fishing conservation association? Every association page has a button — *Claim this page* — which opens a short form. Write who you are, your role in the association, and what needs updating. We review incoming changes by hand and get in touch before anything is published. This is also the route if the association wants information already published to be changed or removed.

Are you an angler who has spotted something wrong? Send a short line to hej@fangstrapport.se saying which page it is and what is wrong. It helps more than you would think — we do not have eyes on all 40,000 lakes.

Do you have catches on a water where the rule information is missing? Log the catch anyway. Private catches are visible only to you; public catches contribute to the water's page and help other people find where the fishing is. The rules are imported separately from HaV and the county boards, and are not affected by individual catch reports.