Applications

Weighing Equipment for Fisheries Research Vessels

Updated September 15, 20263 min readBy WPL Industries Engineering

Short answer

A fisheries research vessel typically needs a motion-compensated bench scale for baskets and subsamples, a scientific scale at the measuring station for individual fish, a high-resolution small-platform scale with wind cover for gonads and stomach contents, and a platform scale on deck, all connected directly to the survey data system.

What a fisheries research vessel needs to weigh

A fisheries research vessel needs weighing equipment for four jobs: catch categories and subsamples at the sorting area, individual fish at the measuring station, small biological samples in the wet laboratory, and occasional large or bulky items on deck. Each job has its own capacity, readability and handling needs, so a practical set-up combines several scales connected to the survey data system.

The scientific background is covered in the Research Vessels hub. This page focuses on equipment: what to install where, and how to prepare it for a survey.

Station-by-station weighing tasks

Survey protocols such as the ICES North Sea IBTS manual define what is sorted, measured and sampled; the table translates those tasks into weighing requirements.

Station	Weighing tasks	Typical mass range	Key requirements
Sorting area	Catch categories per species, sex and size; subsamples for length measurement	Around 100 g to 60 kg per basket	Fast, motion-compensated, washdown-proof, basket tare presets
Measuring station	Individual fish weights with length, sex and maturity	About 1 g to 6 kg	Short settling time, direct data capture, platform fitting the fish
Wet laboratory	Gonads, livers, stomach contents, small fish	Below 1 g to a few hundred grams	0.1 g readability, wind cover, stable bench
Deck	Very large catches, large elasmobranchs, tubs, gear items	Tens to hundreds of kilograms	Robust platform, flip-up or ramp access, washdown
Small boats and coastal work	Sampling from tenders, beach or port sampling	Grams to tens of kilograms	Battery power, carrying case

In a Cefas analysis of survey data, the smallest fish were weighed to 0.1 g, medium fish to 1 g and large fish to 5 g or 10 g (Silva et al., 2013), which illustrates why one scale rarely covers all stations.

Recommended WPL set-up

The following configuration covers the stations of a typical demersal survey; smaller vessels can combine stations.

Station	Suggested equipment	Why
Sorting area	M2-L or M2-XL with 30 kg (5–10 g) or 60 kg (10–20 g); wall or column mount	Motion-compensated, AISI 316, rounded edges for washdown; USB, RS232 and Ethernet
Measuring station	M3 270 × 270 mm with 1,500 g (0.5–1 g), 3,000 g (1–2 g) or 6,000 g (2–5 g)	Larger platform for fish; 316L stainless steel, waterproof
Wet laboratory	M3 120 × 120 mm with 300 g (0.1–0.2 g) or 600 g (0.2–0.5 g), with wind cover	Small samples need fine readability and protection from air movement
Deck	M5 flip-up or M6 with optional ramp, 600 kg (200–500 g)	Four load cells; M5 compensates motion, tilt and gravity changes, M6 motion and tilt
Portable sampling	M3 or M2-S with battery and carrying case	Work away from mains power
Data and service	WeightControl and R10 Configuration Panel	Automatic logging, CSV and JSON API; calibration, diagnostics and backup

Selection criteria behind this table are explained in Choosing a Scientific Marine Scale for a Research Vessel.

Integrating scales with survey data systems

Direct data capture is the single biggest improvement most survey set-ups can make, because it removes transcription errors and links each weight to the right haul, species and fish. Survey software can receive weights over the M2's RS232, USB or Ethernet interfaces, over Bluetooth LE or USB options on the M3, or through the WeightControl API, which returns the current weight and stability status in JSON and accepts commands such as Zero, Tare and Print.

Agree the units and fields with the data manager before the survey; ICES DATRAS, for instance, stores weights in grams. More on integration patterns is in the Data Integration hub.

Commissioning checklist before a survey

Calibrate each scale traceably ashore, or confirm that calibration is still valid.
Install and level scales on rigid mounts, as low and close to midships as the layout allows.
Fit wind covers on small-platform scales in the wet laboratory.
Load presets for basket tares and species where used.
Test data capture with the survey software during a mock station in port.
Stow test weights matching each range and schedule a check every watch.
Brief operators on stability indication, taring and what to do if a check fails.

Stomach and organ sampling protocols, such as the ICES stomach sampling manual, determine whether small samples are weighed on board or frozen for the laboratory, so align the wet-lab set-up with the sampling level planned.

Frequently asked questions

Can one scientific scale serve both the measuring station and the wet lab?

On small vessels it can, but it slows sampling and compromises resolution. Individual fish need a larger platform and short settling time, while small samples need fine readability and a wind cover. Two scales let both tasks run in parallel during a busy haul.

What should happen if a test-weight check fails at sea?

Stop using the scale for data, flag values recorded since the last successful check, and look for simple causes such as debris under the platform, a loose mount or a wrong tare. If the check still fails, switch to a spare scale and recalibrate when possible.

Do deck platform scales need motion compensation on research vessels?

Yes, if the weights are recorded as data. A large load on a moving deck experiences the same apparent-weight changes as a small one, and a tilted platform adds error. Platform scales with motion and tilt compensation give usable values for large catches and specimens.