Fish Slaughter Apparatus Using Linear DC Electric Field
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Solution Overview
Problem
Current methods for slaughtering freshwater fish, such as trout, are either inhumane or result in damaged fillets due to excessive pain, muscular contractions, and hemorrhaging, leading to high rejection rates and inefficiencies in fish farming.
Innovation Solution
A method and apparatus using an elongated passage with longitudinally spaced electrode pairs generating a linear electric field via a DC supply for stunning and a subsequent pulsed DC waveform for killing fish, ensuring they exit in a dead state without severe muscular contractions or damage, utilizing a carefully controlled voltage gradient and pulse waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If AC electric field is applied to stun and kill fish, then fish killing efficiency is improved, but fish suffer severe muscular contractions causing broken backs and hemorrhaging
Solution Approach 1:
The patent changes the electrical parameter from AC waveform to DC waveform. This parameter change eliminates the severe muscular contractions and hemorrhaging caused by AC while maintaining effective fish stunning and killing. The DC electric field provides controlled stimulation without the repetitive contraction cycles inherent in AC systems.
Solution Approach 2:
The patent employs pulsed DC electric field application with specific pulse durations and intervals. This periodic action allows the fish nervous system to respond to each pulse without sustained muscular contractions, preventing the cumulative damage seen in continuous AC application while maintaining effective stunning and killing.
2Object-affected harmful factors
If fish are stunned using DC electric field, then fish are immobilized without severe contractions, but additional processing time is required to ensure complete killing
Solution Approach 1:
The patent applies a first DC electric field to preliminarily stun and immobilize the fish before applying a second, more intense DC electric field to ensure complete killing. This preliminary action prevents muscular contractions during the initial phase while preparing the fish for the subsequent lethal phase, optimizing both welfare and efficiency.
Solution Approach 2:
The patent divides the electric field application into two distinct phases: a first DC phase for stunning and immobilization, and a second DC phase for killing. This segmentation allows each phase to be optimized independently - the first phase minimizes stress and contractions, while the second phase ensures rapid and humane killing.
3Shape
If fish are filleted before rigor mortis, then fillet quality is improved visually, but gaping occurs in the flesh reducing taste quality
Solution Approach 1:
The patent applies electric field treatment as a preliminary action that accelerates the onset of rigor mortis while preventing the severe muscular contractions that cause hemorrhaging. This controlled preliminary action allows filleting to be performed at the optimal time - after initial stunning but before excessive rigor sets in - maintaining both visual appearance and flesh integrity.
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 solution provides humane slaughter with minimal fish damage and high fillet quality by avoiding rapid voltage increases and using direct current, ensuring fish exit in a dead state with no serious hemorrhaging, thus reducing waste and improving processing efficiency.
Implementation Method 1
generating a linear electric field in the water along at least a first region of said passage, thereby inducing electro-anesthesia or stunning of the fish passing through said first region of the passage
Implementation Method 2
applying a further electric field in the water in a subsequent region of the passage, downstream of said first region, to kill the fish
Data Source
AI summary
A method of slaughtering fish comprising the steps of providing an elongated passage, passing fish entrained within a flow of water through said passage, and generating linear electric field in the water along at least a first region of said passage, thereby inducing electro-anaesthesia or stunning of the fish passing through said first region of the passage, and applying a further electric field in the water in a subsequent region of the passage, downstream of said first region, to kill the fish such that the fish exit a downstream end of said passage in a dead state.