The Trap Left In Too Long at Emma Lake
It was the end of a long deployment run and the retrieval time from the previous night's fyke set at Emma wasn't written down — it was "remembered." When the catch data came back to the office, the elapsed time couldn't be calculated accurately, and with it went the CPUE denominator for the longfin tūna records from that set. Three fish, all large bodied, lengths recorded as 68, 72, 54 cm. Usable data for size distribution. Useless for any effort-corrected density estimate.
That is the kind of loss this template is designed to prevent. Deployment date and deployment time, retrieval date and retrieval time — four fields that, when all four are filled in, make every catch record a complete, auditable data point rather than an orphan observation.
The Architecture of a Trap Set Record
The template is organized in sections that mirror the physical sequence of a fyke net deployment: site characterization, trap specification, timing, and catch. That sequence is deliberate, and it matters.
The habitat multichoice field — macrophytes, soft bottom, hard bottom, willow, native tree, tussock — records the microhabitat at the trap location. At Clearwater or Roundabout, the difference between a set in macrophyte beds versus open soft bottom drives catchability for kōaro and banded kōkopu in ways that aren't consistent across species or seasons. Kōaro tend toward harder substrates with cover; giant kōkopu associate more strongly with macrophyte edge habitat and submerged willow structure. When habitat type is recorded per trap set and later cross-referenced with species composition, the habitat preference patterns become legible across the dataset.
Water appearance — clear, green, turbid, milky — is a water quality proxy that contextualizes the catch. A turbid record at Camp coinciding with reduced kōkopu catch compared to the same trap location in a clear-water survey tells you something about either visibility-driven trap avoidance or genuine population fluctuation. Without the water appearance record, you're comparing numbers that aren't comparably derived.
Water depth in meters locates the trap vertically in the water column. Fyke nets set at 0.4 m in macrophyte fringe habitat at the littoral margin fish differently than the same trap set at 1.8 m over soft bottom in the pelagic zone. Trap type — fyke or minnow — and the opening dimensions (width 25/50/65 cm, height 35/40/50/55 cm) complete the gear specification that makes one trap set comparable to another.
The Length Data That Builds Population Structure Over Years
Each species has its own dedicated length field. The hint says "comma separate lengths." It's the correct format for this kind of bulk measurement entry — when you pull a fyke net and measure twelve banded kōkopu sequentially in the field, you want to enter 82, 71, 88, 65, 79, 93, 68, 74, 81, 66, 88, 77 and move on. The comma-separated string in the field, later parsed in analysis, gives you the full length-frequency distribution for that species at that site on that date.
This matters disproportionately for the galaxiid entries. Alpine galaxias, Canterbury galaxias, longjaw galaxias, and unidentified galaxias are all tracked separately. In a Canterbury lake where the galaxiid community may include sympatric longjaw and Canterbury galaxias, having separate length fields for each is the only way to build size-class comparison data across species and across survey years without conflating the records. Longjaw galaxias run smaller than Canterbury galaxias at comparable ages, and the size-frequency distributions overlap — correct field identification followed by species-specific length entry is the chain that produces defensible population data.
The kanakana field — New Zealand lamprey, a taonga species with critical migratory importance — appears as both a species multichoice option and a dedicated length field. Kanakana are rarely caught in fyke surveys, and a single record from Denny Lake with a length entry is a meaningful observation rather than a routine data point. The field needs to be there, pre-populated and labeled correctly, so that when the uncommon event occurs, it's recorded in the same structured format as every other species rather than added as a note in the Comments field that gets lost in aggregation.
The Comments field is the last data entry section and the right place for it. Equipment anomalies, non-target species observations, unusual weather during the soak period, suspected trap disturbance — anything that doesn't fit the structured fields gets written here. After three seasons of monitoring across five waterbodies, the Comments field at Roundabout starts building a picture of the site's quirks that no structured field captures alone.