YELLOW LINE
STM Products

Continuous protection for stable environments

The passive deterrents of the STM Yellow Line are designed to reduce interaction between dolphins and fishing gear, helping to limit the risk of accidental catches and support more sustainable fishing. Once in water, the devices activate automatically and emit ultrasound that creates a continuous acoustic barrier, prompting dolphins to move away from nets, longlines and aquaculture structures.

Randomised ultrasonic emissions, with output up to 165 dB across the 5–500 kHz range, interfere with dolphins’ echolocation systems, discouraging approach without causing harm to either the cetaceans or the target fish species. Designed to operate autonomously, Yellow Line pingers require no manual input and are ideal for fixed installations along fishing gear and permanent structures.

MAIN TECHNICAL FEATURES

Yellow Line pingers share the same technological core as the entire STM Products range: 32-bit microprocessor, automatic water-activation and randomised ultrasound parameters to prevent dolphin habituation. The watertight housing and rechargeable NiMH batteries make them suited for intensive use at sea, with typical operating depths of 10 to 400 m.

Yellow Line models

DDD 04L

Protection for very long set nets, aquaculture, port areas and marine work zones

The DDD 04L is designed for very long set nets, aquaculture installations, ports, marinas and exclusion zones where reducing dolphin approach to fixed structures is essential. Units are installed in series, minimum 5 recommended spaced 500 m apart, to create a continuous barrier along the entire perimeter to be protected.

DDD 04N

For long set nets

The DDD 04N is suited to set nets and drift nets longer than one kilometre, typically deployed in areas where dolphins regularly interact with fishing gear. A configuration of 3–5 units is recommended, spaced at a constant 500 m interval, to ensure uniform coverage and effective bycatch reduction along the full length of the net.

Accessories for the STM Products Yellow Line

For easier and safer management of Yellow Line pingers, a dedicated range of accessories is available: the VOLTester for quick battery level checks, the STM single charger, and the MBC4 multi-charger for recharging up to four devices simultaneously.