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V. Maccarrone et al. / Turk. J. Fish. Aquat. Sci. 14: 173-181 (2014) 179
Table 4. Surface of net damaged and corresponding economic value of the damages for the control and pinger nets
Total surface of net damaged after 29 hauls (m2) small hole (<20 cm) 17.34 m2 26.44 m2
hole and tears (>20 cm)
Mean surface of net damaged after 29 hauls per every 138.77 m2 147.52 m2
50 m of net (m2) TOTAL
small hole (<20 cm) 156.11 m2 173.96 m2
Total cost of the damage in Euros hole and tears (>20 cm)
0.96 m2 1.47 m2
Total cost of the damage after 29 hauls for each 50 m TOTAL
of net small hole (<20 cm) 7.71 m2 8.20 m2
hole and tears (>20 cm)
8.67 m2 9.66 m2
TOTAL 7.88 € 12.02 €
small hole (<20 cm) 63.08€
hole and tears (>20 cm) 70.96 € 67.05 m2
0.44 € 79.07 €
TOTAL 3.50 € 0.67 €
3.94 € 3.73 €
4.39 €
net but also, albeit with a minor force, attack the the pinger net, based on the PPUE, reaches the
pinger net. Additionally, in the assessment of the ED production levels obtained with the control net five
of the fishing gear, we considered the destruction of days in advance. This result assumes additional
the net surface without taking into account the meaning if we consider that the costs that the boat
efficiency of the net decrease in proportion to the supports during each day of fishing were cut down
number of holes and that the fishermen replace the net (e.g., fuel, engine oil, damage, wear and tear of
before its complete destruction. Based on this “net- equipment, and crew costs), which would improve the
surface damaging method”, the difference between economic and environmental sustainability aspects of
the pinger net and the control net is negligible the fishing activity.
(approximately 10 €). Although it is a rare event, any
attack on the network pinger by the dolphins is an This evaluation showed that the technological
event to be considered, this would result in a lower investment of the fishing company requires economic
cost-effectiveness of this technology. sustainability useful to justify their costs. Particularly
in Sicily, the artisanal fishing boats are used an
As reported in other studies (Brotons et al., average of 110 fishing days (ISMEA, 2005; ISMEA,
2008a; Buscaino et al., 2009; Gönener et al., 2012; 2006). Based on these data and the data collected and
Dawson et al., 1988; Broton et al., 2008b; Gazo et al., analysed in this study, it can be assumed that an
2008; Lauriano et al., 2004), the use of sounds artisanal fishing boat with gill nets and PPUE levels
emitted by specific acoustic devices can, under some similar to those recorded in the presence of predation
circumstances (Dawsons et al., 1998), deter the could recover the investment in the pinger technology
approach of dolphins to the fishing gear, which in less than one fishing season. In this contest, we
reduces the by-catch, the damage to the fishing have to consider that the data obtained in this study
equipment, and the loss of fish. In fact, the pinger are related to a relatively short period (two months),
appears to be one of the few effective methods able to and longer periods of observation should be
reduce the problem of depredation-interaction (Broton considered to exclude any habituation phenomenon
et al., 2008b; ISMEA, 2005). between the dolphins and the pinger. However, in
many Italian artisanal fishing companies, there is a
Unfortunately, the technical-scientific proposals widespread practice to change the type of gear used
to reduce the depredation activities are not always during the fishing season (IUCN, 2008; Taylor,
accepted by fishermen. This resistance is partly due to 1997). This equipment replacement is associated to
a lack of knowledge of the functional principles of the the turnover of the target species and consequently to
operational techniques. The reluctance by the the economic sustainability of the activity (IUCN,
fishermen against the use of pingers could be 2008). Even in the case under study, the fishing boat
explained by three main factors: scepticism about the worked with gillnets for approximately 3 to 4 months
effectiveness of the devices, difficulty in per season/year (80 days) and with trammel nets for
handling/utilisation, and lack of knowledge of the the remainder of the fishing season.
costs/benefits ratio.
The data derived from the experimental fishing
This study allowed us to assess the economic allowed us to evaluate the total ED to be 1397 € in
damage reported by the fishing equipment and the 900 mt of net (77.65 € in 50 m units of net; see Table
economic loss of fish products during experimental 3), which is the loss of income due to the missed
fishing. Moreover, the data of the economic fishing catches of the target species as a result of dolphin
activities allowed us to evaluate the ROI for the depredation.
adoption of this technology.
The results obtained from the economic analysis
Our results have shown that, during the demonstrate that the critical factors of pinger
experimental fishing, the pinger net exhibited a technology could be represented by the economic
production advantage compared with the control net, aspects of the investment sustainability, the ROI, and
which improved the efficiency and effectiveness of the use of economic incentives for the purchase of the
the fishing activities. In addition, in 29 fishing days,
