Buoyant Crowding Net Layout for Low-Stress Fish Relocation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for handling farmed fish, such as in floating fish pens or land-based tanks, are stressful and time-consuming, often requiring significant manpower and vessels, and can be lethal for vulnerable individuals.

Innovation Solution

A crowding net with buoyancy means is positioned within the enclosure, allowing it to be turned inside out by displacing the top edge, forcing fish to swim through a controlled passage, reducing stress and manpower requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional handling methods using vessels and pumps are used, then fish can be moved and handled, but stress and lethality increase significantly

Engineering Contradiction:
Improvestress and lethality to fishVSAvoidhandling efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The invention extracts the harmful pumping process entirely from the system. Instead of using pumps to move fish, the system uses gravity and natural water flow through the passage, eliminating the stress of mechanical pumping while maintaining handling capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The passage structure acts as an intermediary element that allows fish to move between compartments voluntarily. This mediator provides a controlled, low-stress transition path that replaces the harsh pumping mechanism while still achieving the goal of fish relocation and handling

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If traditional handling methods are used, then fish can be counted and graded, but significant manpower and vessels are required

Engineering Contradiction:
Improvemanpower requirementsVSAvoidhandling time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system enables self-service handling where fish move through the passage and are sorted automatically based on their own swimming behavior. The crowding net and passage structure guide fish without requiring active manipulation by operators, reducing manpower while maintaining processing capability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The tank is segmented into multiple compartments separated by the crowding net and passage structure. This segmentation allows different handling operations (counting, grading, treatment) to occur simultaneously in different sections, reducing overall handling time and manpower requirements

Inventive Principle:
Principle #1Segmentation

3Productivity

If a crowding net is used to force fish through a passage, then handling becomes more efficient, but fish stress increases

Engineering Contradiction:
Improvehandling efficiencyVSAvoidfish stress
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The crowding net applies only partial crowding pressure - enough to guide fish toward the passage but not so much as to cause stress. The net is positioned and tensioned to create a gentle funneling effect rather than forceful confinement, maintaining efficiency while reducing harm

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system changes the parameter of water flow rate through the passage to optimize fish movement. By controlling flow velocity and volume, the system creates ideal conditions for voluntary fish passage without requiring excessive crowding pressure that would increase stress

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method enables gentle and efficient handling of fish, minimizing stress and manpower, while allowing for counting, grading, and treatment without the need for additional vessels.

Implementation Method 1

The top edge is provided with buoyancy means

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP4044799B1Device for relocating fish within a receptacle and method for relocating the fish
Publication Date: 2026.02.25 MOWI ASA
  • EP4044799B1 patent drawingFigure 1~2
  • EP4044799B1 patent drawingFigure 3
  • EP4044799B1 patent drawingFigure 4A~4B

AI summary

Fish pen (1) comprising a buoyancy member (11) encircling an enclosure (2) for raising fish (9). The enclosure (2) comprises a side wall (23) and a bottom (25). The fish pen (1) comprises a crowding net (3) positioned within the enclosure (2), and the crowding net (3) forms a top edge (30). The top edge (30) is provided with buoyancy means (31), two side edges (33) and a bottom edge (35), and the length (L) of the crowding net (3) between the two side edges (33) is larger than a diameter (De) of the enclosure (2), and wherein the crowding net (3) is fastened to the side wall (23) along the side edges (33). A method for managing fish (9) in a receptacle for fish by use of the crowding net (3) is disclosed.