Interactions of dolphins with fishing activities is a growing concern for the conservation of these species and for the economic consequences on the fishery sector, as dolphins:

  • steal fish from the nets, sometimes in a highly selective manner, directly causing commercial losses
  • damage and spoil fish already caught in the nets which, being mutilated, is often no longer tradable
  • damage the nets, that need to be repaired or new ones to be purchased
  • scare the schools of fish, reducing the catch rates.
    Furthermore, the time spent by fishermen to manage the interactions with dolphins causes a reduction in time spent on fishing activities.

For this reason, one of the main objectives of this project is the reduction of negative interactions between bottlenose dolphins (Tursiops truncatus) and professional fishing.
Generally, the most effective way to reduce by-catches of these marine mammals is to avoid the use of trawls and other fishing gear within their habitats.

However, this is not feasible when the habitat of the species overlaps with the fishing grounds. Therefore, modifications to fishing gear or the implementation of mitigation devices (known worldwide as Bycatch Reducer Devices, BRDs) must be pursued to mitigate the impact of fishing gear on these protected and sensitive species.

In recent decades, numerous studies have been conducted to find solutions to minimize the incidental capture of dolphins. The LIFE DELFI project builds on this and proposes other innovative mitigation devices.

Acoustics deterrent

The use of active acoustic instruments such as Acoustics Deterrent Devices (ADD) and Deterrent Interactive Devices (DID) known as pingers is a valuable solution to reduce the interception of dolphin bio-sonar capture.
Pingers are acoustic deterrent devices based on a relatively low sound source level (typically below 150 dB 1 μPa at 1 m) and operating from mid-high frequencies (2.5-10 kHz) with harmonics up to higher frequencies. Pingers interact specifically with the acoustic behaviour of dolphins by altering their orientation, their ability to look for food and their intra-specific communication. The use of pingers as a deterrent guarantees multiple objectives: the integrity of fishing gear (avoids damage to nets), the conservation of catches and reduces the incidental catches of dolphins.

In this project more than 300 new generation pingers will be distributed with variable frequencies to be deployed in the nets of more than 100 Italian fishing vessels for a total of more than 300 fishermen involved. The DiD (Dolphin Interactive Deterrent) will be the new prototype of pingers tested for both trawls and gillnets. DiD is a device able to keep dolphins away from fishing nets, thanks to an effective technique of interaction with their echolocation system (sonar). DiD produces ultrasound only when it detects the presence of dolphins in the vicinity through its “hearing” circuits, which is activated by “clicks” emitted by mammals. The advantages of this model compared to DDD are the reduction of the possibility that dolphins can get used to signals, the increased battery life and the reduction of noise pollution.

Visual Deterrents

One approach to developing effective mitigation devices is to consider the biological aspects that induce marine dolphins to interact with fishing gear. Understanding dolphins’ behaviour, mainly their physiology (auditory, chemosensory and visual abilities), is essential to minimize interactions with fishing.
Dolphins rely heavily on visual signals, particularly when close to their prey, thanks to a well-developed visual system with a wide range of reception. This has prompted the development of visual deterrents such as flashing lamps and LED lamps to be mounted on fishing gear to discourage the dolphin’s approach. In LIFE DELFI more than 350 new visual deterrents will be mounted on the nets of at least 30 fishing vessels, for a total of 300 fishing days and 100 fishermen involved.

Alternative gear

Small-scale artisanal fishing plays an important role in MPAs, supporting the local economy. Passive nets (gillnets, trammel nets, combined nets and small driftnets) are widely used in these areas. In order to reduce interactions between dolphins and passive nets (i.e. the depredation of catches and at the same time the bycatch of dolphins), the use of alternative gears is encouraged. More specifically, the idea is to replace the fishing of traditional passive nets with that of pots, which are not dangerous for dolphins and are capable of catching a wide variety of demersal, benthic and pelagic species. Given that interactions between passive nets and dolphins occur mainly from late spring to early autumn, LIFE DELFI does not intend to completely ban the use of passive nets, but promotes the use of alternative gear during crucial periods and in hotspot areas (periods and areas with a high possibility of interaction).

Dolphin watching

The aim of this action is to enable fishermen to supplement their income by promoting dolphin watching activities (Dolphin Watching). 18 training courses (16 in Italy and 2 in Croatia) will be organized to train qualified operators and professionals able to promote and manage dolphin watching activities in the areas of intervention.
The trainings, will be organized involving experts in the field, able to transmit all the necessary information. The courses also aim to combine scientific research, education, and public awareness to achieve effective conservation of the marine environment and will include class lessons and sea trials.
Field monitoring will be conducted using a research boat. The boat surveys will be conducted using a search boat. When in search, the entire crew participates in visually scanning the sea surface. Navigation and environmental data will be collected during the survey. The boat will be handled by qualified personnel with all the necessary permits and extensive boating experience.
To facilitate the participation of the fishermen the courses will take place during the fishing stop period. Each course is divided into 5 modules lasting one day during which the biology and ethology of cetaceans will be illustrated with particular reference to dolphins, the threats to these animals, the recognition techniques.
The dolphin observation activity will be carried out in each MPA involved in the project. This activity will provide an opportunity to move part of the fishing fleet to alternative activities, but it could also be an option to integrate the local economy, especially in those areas where fishing is not so profitable.

Information desks

In order to facilitate the replacement of traditional fishing gear with low impact ones, a technical assistance service for fishermen will be activated to receive information and advice. These Info Desks will help fishermen to prepare the documentation for the application for EMFF (European Maritime and Fisheries Fund, 2014-2020) calls for proposals. Technical assistance will also be provided to facilitate the use of deterrent systems by fishermen and to stimulate the transition from fishing to dolphin watching.
Difficulties in producing administrative documents, certifications, etc. to undertake dolphin watching activities have often hindered the growth of this activity in Italy, although in the project areas the presence of dolphins is widely documented, especially during the summer. Therefore, the information desks will also support the fishermen in the production of all the administrative procedures necessary to undertake Dolphin Watching.

The 8 information desks will be activated from the third year onwards in the following areas:

  • Egadi Islands MPA
  • Torre del Cerrano MPA
  • Tavolara Island MPA
  • Aeolian Islands
  • Ancona
  • Chioggia