Damage or removal of captured fish from fishing gear (depredation) can result in catch loss or a decrease in its economic value and often damages the fishing gear. Depredation by dolphin appears to be growing in frequency, geographic extent, and severity and is responsible for substantial economic losses. Because of this, the fishing industry is in urgent need of mitigation measures that can reduce the frequency and severity of such interactions (Cruz et al 2014).
In some fisheries, the use of alerting devices (deterrent pingers) have been successful in reducing dolphin depredation. However, in many cases the acoustic signals coming from such devices (<150dB) are low in power and after a period of time the dolphin become acclimatised to the low intensity noise and depredation recommences. In some instances, where deterrent pingers have been used to prevent depredation, the depredation observed when they return is much higher than was observed prior to using the deterrent pingers. The anti-depredation pinger is louder than standard deterrent pingers, producing a randomised unpredictable sound that startles dolphins when in close proximity to the net. A 100m spacing is recommended for maximum effect; this can be varied depending on fishing gear, region and dolphin species.
The dolphin anti-depredation pinger is secured in our established super-durable rubber carrier as used by our range of deterrent pingers. The pinger unit has a depth rating of 800m and has been tested to below 1000m. Toughness means longer life, greater reliability and reduced costs.
The pinger unit can be swapped with a spare unit with a fresh battery so that the battery can be changed in a dry place – no untying required! The immersed weight in water is 37g (compared to immersed weights of up to 120g for other pingers on the market) so it can be threaded onto the ropes joining net panels on either head or foot rope without interfering with the set of the net. *It’s no accident the pinger is shaped like a banana! We have engineered the casing to ensure that when the pinger comes back on-board it doesn’t get caught on the rails – the banana shaped casing means the pinger rotates smoothly over the rails on hauling preventing snags and subsequent downtime in fishing operations.
User review of how our anti-depredation pingers, after prolonged use, are continuing to resolve fisher-dolphin conflict in the Mediterranean Sea. Re-iterating feedback we’re getting from around the world in purse seine, longline & set-net fisheries.
Depredation of target fish by cetaceans causes economic hardship for the fishers. See how we’re resolving this fisher-cetacean conflict in the US with our new anti-depredation pinger. Video with Spanish subtitles.
In addition to being cheap, durable, effective and easy to use, we have considered the needs of fisherman and built in some simple yet effective technologies that make the dolphin anti-depredation pinger a market leader:
Indicator lights that let the fishers know when the battery will need to be replaced. The pinger has a bright LED light that flashes continuously and switches from a green flash to a red flash when a battery change is needed. The flash is visible in direct sunlight, but switches off once immersed in water to conserve battery power.
The safest pinger! The low weight, rubber housing removes the risk of injury to fishermen. The absence of lithium batteries used in other acoustic deterrents removes the fire or explosion risk. The method of attachment avoids weakening net ropes and the robust construction means no broken pingers with sharp edges, even in the harshest of conditions!
LONG BATTERY LIFE
The battery lasts 175 hours and is cheap and easy to replace*. The pinger has an advanced sensor so that it reliably turns off when out of water. Pingers do not stay on when in contact with wet nets, such as net bins, further conserving battery life.
*batteries are replaced by the user without having to order expensive replacements from suppliers/manufacturers – batteries are a standard C2 alkaline cell that can be brought at your local supermarket.
BUY ANTI-DEPREDATION PINGERS
Dolphin Anti-Depredation Pinger (40kHz)
- Frequency 40kHz
- Battery Life 175 hours
- Dimensions 185mm x 52mm x 42mm
- Weight (with battery) 229 grams
- Space the pinger every 75-100m
- Sound level 175dB +/- 3dB @ 1m
The sound transmitted from our ultrasonic deterrents (>20kHz) cannot be heard by the naked ear. Testing pinger functionality is important in being able to determine if the pingers are functioning and continuing to deter cetaceans. We have developed a low cost pinger detector which allows fishers and managers to test their pingers functionality.
Pinger Maintenance Kit
Maintain your acoustic deterrents by replacing the O-rings every two years or when needed. 5 x O-rings and silicon grease included.
Our high powered alkaline c-cell batteries can be brought in bulk and at cost price from us direct. Suitable for anti-depredation and deterrent pingers. Box of 24 batteries
Fish with more than one net? Want to switch pingers between gear with ease to remain compliant? Buy our spare rubber carriers (bananas) and just slot the pinger units across in seconds. None of the hassle of untying and re-attaching pingers seen with other pinger models!