wels catfish
Enable an agent to recognise wels catfish, assess an individual or population in its ecological context, and determine which interventions require further evidence or local authorisation.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to recognise wels catfish, assess an individual or population in its ecological context, and determine which interventions require further evidence or local authorisation.
The wels catfish, Silurus glanis Linnaeus, 1758, is a large, scaleless freshwater fish species in the family Siluridae, native to substantial parts of central and eastern Europe and western Asia, distinguished by a broad flattened head, six barbels and a long anal fin.
It can be Evaluate an identification using diagnostic photographs, a regional key or appropriately validated molecular evidence.; Attach measured size, condition and reproductive observations to an individual without generalising them to the species.; Locate an occurrence within a drainage and investigate native, introduced or uncertain origin.; Assess whether repeated detections demonstrate occupancy, reproduction or successful recruitment.; Investigate predation and ecological effects using local evidence and explicit alternative explanations.; Determine the evidence, expertise and current local permissions needed before capture, sampling, movement, release or removal..
Distinguishing features
Inspect the underside of the head for two pairs of chin barbels; record their positions and visibility rather than identifying the fish from whiskers alone. [FishBase](https://www.fishbase.se/summary/Silurus-glanis.html)
Check for a very long anal fin approaching the tail together with a small dorsal fin; an eel-like outline alone is insufficient. [FishBase](https://www.fishbase.se/summary/Silurus-glanis.html)
Verify the combination of scaleless skin, a broad flattened head and absence of an adipose fin; no single feature establishes the species. [FishBase](https://www.fishbase.se/summary/Silurus-glanis.html)
Inspect the rounded or truncate tail as part of the full character combination, and require a regional identification key when another Silurus species is plausible. [FishBase](https://www.fishbase.se/summary/Silurus-glanis.html)
Scope
+ Taxonomic identity, diagnostic morphology and identification confidence
+ Individual life stage, sex, size, reproductive condition and health
+ Population identity, recruitment and connectivity
+ Habitat use, drainage-level distribution and native or introduced provenance
+ Predatory interactions, conservation assessments and evidence needed for management
- Other catfish species and the general model of catfishes
- Processed catfish meat, food products and food-safety certification
- Fishing equipment, angling activities and fisheries businesses
- Whole freshwater ecosystems and their complete food webs
- Aquaculture facilities and their operating systems
Characteristics
- Taxonomic identity
- Accepted scientific name, authority, family, GBIF taxon identifier, NCBI taxonomy identifier and dated source Connects observations to the intended species while exposing database disagreements.
- Observation subject
- Species concept | drainage population | sampled group | identified individual | unidentified occurrence Prevents a species assessment from being mistaken for the condition of one fish.
- Identification confidence
- Unconfirmed | probable | confirmed; evidence and identification method required Separates suggestive photographs or environmental DNA detections from adequately supported identification.
- Total length
- cm; measurement method, date and uncertainty Supports growth and handling assessments without treating size as a reliable substitute for age.
- Body mass
- kg; measured or estimated, with method and date Supports condition assessment and planning for handling a potentially large fish.
- Life stage and reproductive condition
- Egg | larva | juvenile | adult | unknown; immature | developing | spawning | spent | unknown Distinguishes survival, growth and recruitment evidence.
- Sex determination
- Female | male | undetermined; method and confidence Prevents unsupported inference from body size or external appearance.
- Population origin
- Native | introduced | uncertain; drainage, evidence and reference period Makes origin local and historical rather than assigning one status to the species everywhere.
- Occupied-water conditions
- Temperature in °C, dissolved oxygen in mg/L, depth in m and salinity with stated unit; time and location Relates occupancy and individual stress to measured conditions without inventing universal tolerance limits.
- Population persistence
- Detection only | repeated occupancy | reproduction evidenced | recruitment evidenced | unknown Separates a released or transient fish from a self-sustaining population.
- Conservation assessment
- Assessment body, category, assessment year, geographic scope and source Keeps global extinction risk distinct from regional decline and introduced-population management.
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Species identity Establishes which catfish taxon and observational subject a record concerns.
The common name must resolve to a species without collapsing individuals, populations and related catfishes.
Taxonomic anchor
Connects the registry concept to named taxonomic authorities.
Accepted name and identifiers
Use Silurus glanis Linnaeus, 1758 as the verified name anchor; record each database identifier with its taxonomic source and version. [GBIF](https://www.gbif.org/es/species/2337607)
- Which taxonomic source establishes the accepted name, authority and placement in Siluridae? provenance
- Which GBIF and NCBI identifiers resolve to this species, and do either represent a synonym or a different taxonomic treatment? boundary
Diagnostic evidence
Makes identification reviewable from observed characters.
Catfish character combination
Assess chin barbels, fin arrangement, skin and head shape together, retaining missing or obscured characters as uncertainty.
- Are the two pairs of chin barbels and the full dorsal, anal and tail-fin arrangement visible? measurement
- Which locally plausible catfish species remain unexcluded, and what additional view or test would distinguish them? action
Individual development Records growth, life stage and reproductive evidence for individual wels catfish.
Large size, maturity and age must remain separate judgments, and sex requires an explicit determination method.
Growth and condition
Interprets measurements in relation to individual history.
Size without age assumption
Keep length, mass, age estimates and health observations distinct; retain capture and measurement conditions.
- What total length and mass were measured, by which methods and with what uncertainty? measurement
- Is age supported by a validated ageing method or known history, rather than inferred from impressive size? provenance
Reproductive state
Distinguishes sex, maturity, spawning activity and offspring stages.
Sex and spawning evidence
Require evidence for sex and maturity, and distinguish observed spawning or nest attendance from assumed reproductive behaviour.
- How were sex and reproductive condition determined, and which external dimorphisms are validated for this life stage? measurement
- What observations establish spawning, eggs, larvae or nest attendance at this location and date? provenance
Drainage and habitat Places occurrences within connected waters and a documented distribution history.
A country-level occurrence cannot establish native status, accessible habitat or population connectivity.
Range provenance
Separates historical range, introductions and uncertain records.
Native or introduced population
Assign origin to a defined drainage population using dated evidence; keep introduced status separate from demonstrated ecological harm.
- Which historical records establish whether wels catfish is native to this drainage? provenance
- Could this occurrence reflect stocking, escape, dispersal through a new connection or identification error? boundary
Occupied habitat
Relates detections to water conditions, shelter and connectivity.
Habitat use and access
Record the conditions actually occupied and the routes connecting feeding, refuge and potential spawning areas.
- What temperature, oxygen, depth, flow and shelter conditions accompanied the observation? measurement
- Which barriers or waterway connections constrain movement between occupied and potential reproductive habitats? boundary
Population and predation Assesses persistence and feeding relationships without extrapolating from isolated observations.
Detection of a large predator does not establish recruitment, abundance or a causal ecosystem effect.
Population establishment
Distinguishes presence from a reproducing and recruiting population.
Recruitment and detection
Evaluate size classes, juvenile survival and survey effort alongside stocking history and repeated detections.
- What evidence distinguishes locally produced juveniles from stocked fish? provenance
- How do sampling gear, effort, season and habitat coverage affect estimated abundance and apparent absence? measurement
Feeding effects
Connects prey evidence to effects at the appropriate scale.
Diet versus population impact
Separate a recorded prey item from a recurring dietary pattern and from a demonstrated effect on prey populations.
- Which prey are supported by direct observation, stomach contents or other validated dietary evidence for this population and size class? provenance
- What comparison or time series distinguishes effects of wels catfish predation from habitat change, fishing and other predators? boundary
Conservation and intervention Connects population evidence to conservation interpretation and proposed handling or management.
The appropriate response depends on locality, origin, population condition and the specific intervention.
Assessment scope
Keeps global, regional and local judgments attributable and separate.
Dated conservation assessment
Record an IUCN category only with its assessment year and source, alongside independently sourced regional assessments.
- What is the latest verified IUCN assessment category and assessment year for Silurus glanis? provenance
- Does the focal population have a different regional conservation assessment or introduced-species designation? boundary
Handling and management
Makes a proposed intervention specific enough to assess.
Intervention readiness
Evaluate capture, sampling, transport, release or removal against fish size and condition, local rules and the intended population outcome.
- What current rules apply to the proposed action at this water body, including any restrictions on transport or release? action
- What expertise, equipment and welfare measures are required for the observed size and condition, and how will the outcome be checked? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This is recalled knowledge, with no sources consulted; verify exact GBIF and NCBI identifiers.
- Check the current IUCN category and assessment year, regional conservation assessments and applicable fishing or stocking rules.
- Check native-range boundaries and locally representative adult sizes; no formal subspecies or varieties are asserted here.
- Which of these check these first hold for the sense of wels catfish this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Zoological scientific name - Silurus glanis Linnaeus, 1758 - Names the species, not an individual fish or a local population.
- GBIF taxon key - Numeric taxon identifier - The exact key requires verification against the GBIF taxonomic backbone.
- NCBI Taxonomy ID - Numeric taxonomy identifier - The exact species identifier is not confidently recalled.
- Which of these identifiers and schemes hold for the sense of wels catfish this model covers, and on what evidence? provenance
Standards and regulation
Recalled without web access and unsourced; every item is a lead to verify.
- International Code of Zoological Nomenclature, maintained by the International Commission on Zoological Nomenclature, governs the species name.
- Which of these standards and regulation hold for the sense of wels catfish this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Commercial and subsistence freshwater fishing.
- Recreational angling, particularly for large specimens.
- Aquaculture for food production.
- Research on large freshwater predators and introduced-species effects.
- Which of these real-world use hold for the sense of wels catfish this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Adult total length - Approximately 1-2 for many mature fish; size varies strongly with age and habitat, and exceptional individuals exceed this range - m
- Number of barbels - 6: two long upper-jaw barbels and four shorter lower-jaw barbels - barbels
- Which of these typical measurements hold for the sense of wels catfish this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Introduced populations can alter food webs through predation on native animals.
- Movement or stocking of live fish can establish populations outside the native range.
- Habitat degradation, pollution and disrupted river connectivity can affect local populations.
- Large individuals can be difficult to handle safely during capture and release.
- Which of these failure modes and hazards hold for the sense of wels catfish this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Native across substantial parts of central and eastern Europe and western Asia; precise native boundaries need checking.
- Introduced populations occur in parts of western and southern Europe, including the Iberian Peninsula.
- Growth, diet and reproductive timing vary with temperature, prey availability and local habitat.
- Which of these regional variation hold for the sense of wels catfish this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Catfish - Catfish denotes the broader order Siluriformes; wels catfish is one species within it.
- European eel - Anguilla anguilla is an anguilliform fish without the wels catfish's six barbels and broad, flattened head.
- Wels catfish population - A population comprises members of the species in a particular area; its abundance or introduced status does not describe the species everywhere.
- Wels catfish meat - Meat is a food material derived from individual fish, not the living organism or species taxon.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of wels catfish this model covers, and on what evidence? provenance
What the second pass must settle
- Which current GBIF taxonomic treatment and NCBI taxonomy identifier should anchor this registry entry, and how should identifier changes be tracked?
- What is the latest verified IUCN category and assessment year, and which regional assessments materially differ?
- Which drainage-level sources reliably delimit native range and distinguish historical introductions from subsequent natural dispersal?
- Which sex-determination methods, external dimorphisms, maturity estimates and spawning requirements are sufficiently validated for the relevant populations?
- Which local studies establish recruitment, environmental limits and predation effects strongly enough to support management decisions?