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Article

Describing Dolphin Interactions with Cypriot Fisheries Using Fishers’ Knowledge

by
Marios Papageorgiou
1,2,
Soteria-Irene Hadjieftychiou
3,
Chistodoulos Christodoulou
3,
Antonis Petrou
3 and
Dimitrios K. Moutopoulos
1,*
1
Department of Fisheries and Aquaculture, University of Patras, 30200 Mesolongi, Greece
2
Enalia Physis Environmental Research Centre, Acropoleos 2, Aglantzia, Nicosia 2101, Cyprus
3
AP Marine Environmental Consultancy, Acropoleos 2, Aglantzia, Nicosia 2101, Cyprus
*
Author to whom correspondence should be addressed.
J. Mar. Sci. Eng. 2024, 12(12), 2240; https://doi.org/10.3390/jmse12122240
Submission received: 31 October 2024 / Revised: 29 November 2024 / Accepted: 4 December 2024 / Published: 6 December 2024
(This article belongs to the Special Issue Advances in Marine Biodiversity and Conservation)
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Abstract

:
The study explores the interactions between dolphins and Cypriot fisheries, emphasizing the economic impact and fisher perceptions through data collected from structured interviews with small-scale and large pelagic fishers. The research documents frequent dolphin interactions, impacting catch and gear in both fishing sectors. Reported financial losses and gear damage highlight a significant economic burden, with annual losses averaging EUR 6144 for small-scale and EUR 29,882 for large pelagic fishers. Efforts to mitigate these interactions, such as using acoustic deterrents, have shown mixed results, reflecting dolphins’ adaptability to human activity. While some fishers use deterrents, others remain hesitant due to cost and inconsistent efficacy. The study underscores the need for improved, sustainable solutions that integrate fisher input to enhance acceptance and effectiveness. Findings suggest that dolphins are increasingly relying on fishing activities as a foraging strategy, aligning with broader trends in the Mediterranean. In the context of EU Directive 2014/89/EU, the study integrates ecological considerations and socioeconomic impacts to ensure balanced marine management strategies. This work emphasizes the complexity of human–wildlife conflicts in marine environments, suggesting that further research and collaboration with fishers are essential to developing adaptive strategies that balance conservation with the economic needs of local fishing communities.

1. Introduction

Marine mammals–fisheries interactions have been well documented across the world with different fishing gears and targeted species [1,2,3,4,5,6,7,8,9]. From the mutually beneficial, like cooperative fishing between fishers and marine mammals [10,11,12], to the most detrimental, like direct killing as a retaliatory measure [13,14], these interactions can take different forms. The term interactions refers to the direct [15,16] and physical contact of marine mammals with the fishing gear in the form of depredation or incidental capture. Depredation refers to the damage or removal of catch or bait from the fishing gear by marine predators [15]. The competition for the same biological resources is known as biological or indirect interactions between marine mammals and fisheries [17]. Bycatch refers to any non-targeted species that is unintentionally caught on fishing gear. Incidental capture of marine megafauna on fishing gear, also known as bycatch, is a result of the direct interaction with fishing gear, usually in the form of depredation, which leads to accidental entanglement or hooking [16]. Bycatch may result in minor or major injuries and high pre- and post-release mortality of the bycaught animals [16] depending on the type of fishing gear [18,19]. Marine megafauna taxa, such as marine mammals, marine turtles, elasmobranchs, and seabirds, are extremely vulnerable to bycatch due to the relatively low abundance of their populations and life-history characteristics, i.e., long life spans, late maturity, and few offspring [20]. Bycatch has been considered a major threat to marine mammals, being responsible for hundreds of thousands of individuals killed annually in the world [16,21].
From a socio-economic perspective, marine mammals–fisheries interactions cause significant damage to the fishing gear and catch as well as reduce catch size, quality, and efficiency, being responsible for thousands of euros of economic loss per fishing boat [22,23]. These interactions and depredation in particular are among the greatest concerns and subjects of complaint for the fishers [24]. During the attempt to remove fish from the nets, marine mammals may twist the net or tear the net apart, creating large holes [3,13,25,26]. The presence of dolphins during fishing operations may scatter the potential catch, reducing this way the catch efficacy and daily profits of fishers [23,27,28]. Damages to fishing gear and reduction in fishers’ annual profits due to depredation are the reasons that may have lead some fishers to practices like direct killing as a retaliatory measure [13,14].
In the Mediterranean Sea, marine mammal–fisheries interactions have a long history [20]. The common bottlenose dolphin (Tursiops truncatus) is the most common dolphin species reported to interact with fisheries in the Mediterranean Sea [1,3,9,20,22,23,24,29,30]. This is attributed to its opportunistic feeding behavior and high dietary diversity [25,26,31], wide distribution, high adaptability to human activities, and high cognitive abilities to identify new foraging opportunities [9,32,33,34]. Its preferences for demersal and often highly commercial fish species, as well as its coastal distribution, overlap with coastal fisheries, further contributing to these interactions [31,34,35,36]. Other cetacean species, like the common dolphin (Delphinus delphis), the striped dolphin (Stenella coeruleaolba), the Risso’s dolphin (Grampus griseus), the rough-toothed dolphin (Steno bredanensis), the sperm whale (Physeter macrocephalus), the fin whale (Balaenoptera physalus), the long-finned pilot whale (Globicephala melas), and the Cuvier’s beaked whale (Ziphius cavirostris), have also been reported to interact with fisheries in the Mediterranean [20]. Cetaceans’ advanced learning abilities and quick knowledge transfer within populations enable them to explore new foraging grounds and opportunities, like taking advantage of fisheries’ catch [37,38,39,40]. It is also likely that some dolphin populations may become fully or partially dependent on fisheries to access an easily accessible food source with the minimum energy spent [41], a foraging strategy common among cetaceans [42].
Different measures have been used to mitigate marine–mammal interactions, including, but not limited to, the use of acoustic deterrent devices, gear modifications and changes in fishing practices, redistribution of fishing effort, and fishing spatiotemporal closures, with different effectiveness depending on the species, fishing gear, targeted species, and geographical area [43,44,45]. While these measures have been implemented to primarily mitigate bycatch, their social and ecological impacts are often overlooked, not taking into full consideration their impact on fishers [46,47]. Mitigation measures such as spatial and temporary closures [47,48,49] and redirection of fishing effort [50] could directly impact fishers’ livelihoods and exacerbate social injustices for fishers, potentially leading to conflicts between fishers and the regulatory authorities [47]. Therefore, addressing the socioeconomic impacts of bycatch mitigation measures is crucial in avoiding potential social conflicts [50,51,52]. Incorporating fishers’ knowledge, attitude, and perception in the development of management measures and in decision-making helps towards the acceptance and successful implementation of these measures by fishers and to the better understanding of their impact on fishers lives [53,54,55].
Marine mammals in Cyprus are protected by various protective measures, including national (Nature and Wildlife Protection and Management Law (N. 153(I) 2003) and Fisheries Regulations (P.I. 273/1990)) and European (Annex II and IV EU Habitats Directive (92/43/EEC)) legislations and regulations. The Republic of Cyprus has also been a party to ACCOBAMS (the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea, and contiguous Atlantic area) since 2006. Marine mammals have been previously reported to interact with the small-scale [56,57] and pelagic longline fisheries [29] in Cyprus. However, there is still a big knowledge gap in our understanding of the topic as these interactions continue to grow, causing further human–wildlife conflicts. Improving our understanding on the topic will potentially lead to better marine mammals–fisheries mitigation and conservation actions. The most reliable method to collect fisheries data are through onboard observations; however, this approach requires long-term effort and high resources. In data-limited topics and with limited resources, interviews provide an alternative data collection methodology to assess the interactions between marine mammals and fisheries. This approach enables researchers to gather species’ information regarding their ecology, spatial distribution, feeding habits, behavior, and abundance, as well as on the identification of high conflict areas, seasons, and fishing gears [30,58,59]. Using fishers’ ecological knowledge (FEK), an important source of information in fisheries science [53,60,61,62], the study aimed through in-person interviews that were conducted with small-scale and pelagic longline fishers across the Republic of Cyprus to: (i) characterize the interactions between dolphins and fisheries in Cyprus in terms of seasonality, fishing gear, depth, etc. (ii) estimate dolphin interactions and bycatch rates, (iii) estimate economic loss on catch and gear due to dolphin depredation, and (iv) gather fishers’ knowledge and perception on potential dolphin mitigation measures.

2. Materials and Methods

2.1. Description of Fishing Fleets

The study involved fishers from the small-scale (SSF) and large pelagic (LPF) fisheries. The professional SSF fleet segment is described as “vessels using polyvalent ‘passive’ gears only” and consists of wooden boats between 6 and 12 m in length, operating exclusively in Cypriot waters (GSA25), primarily using bottom set nets and bottom longlines to target demersal species. The LPF fleet segment is described as “vessels using polyvalent ‘passive’ gears only” and includes wooden boats (with one exception being metal) between 12 and 18 m and operates around Cypriot waters using mainly pelagic drifting longlines to target large pelagic fish such as albacore tuna, swordfish, and bluefin tuna [63]. Secondary fishing gear used by LPF includes, but is not limited to, bottom set nets and bottom longlines for demersal species and purse seines for small pelagic fish [64]. Subsequent data analysis focused exclusively on fishing activities associated with drifting pelagic longlines for the LPF fleet segment, while for the SSF fleet segment, it concentrated on activities involving set nets. In 2023, the number of SSF vessels with professional fishing licenses was 288, and 32 vessels for LPF [63]. However, in 2023 a temporary cessation scheme of fishing activities occurred, and only 20 out of the 32 licensed LPF fishers were actively fishing considered in the study (pers. comm. Fisheries Office).

2.2. Data Collection and Sampling Design

Interviews were conducted with SSF and with LPF from different ports across all regions of the Republic of Cyprus between March and June 2023. According to the official country data of 2023, the interviews covered 19% and 45% of SSF and LPF active registered fishing vessels, respectively. Fishers were randomly selected for the interviews during the visits to the ports, and interviews were conducted when fishers returned to the port from a fishing trip or when they were mending their gear. Port visits were frequent to interview all fishers, systematic or not.
Prior to the interviews, the participants were informed about the aims of the study and were ensured about the anonymity of the interview through a consent form and verbally accepted to participate in the study. Additionally, it was clarified from the beginning that the study had nothing to do with any regulatory authorities. These were important steps in gaining the participants’ trust, as there were sensitive questions, such as reporting dolphin bycatch and measures taken to mitigate depredation, where their fear of prosecution could potentially influence their responses.
To maximize the clarity and consistency of the responses, the interviews followed standardized methodologies previously used in fisheries studies [22,23,29,57,65,66]. Interviews were conducted in-person by a trained interviewer and in private with the participant to avoid the influence of other fellow fishers. The interviewer always appeared neutral during the interviews to avoid influencing participant’s responses and never rushed to the next question, hence allowing the time needed by the fisher to respond. At the end of each interview, the interviewer evaluated the reliability and the overall trustworthiness of the information provided based on the participant’s honesty, level of engagement, and confidence in their answers.
A semi-structured questionnaire developed by [23] was constructed, divided into six parts, and consisting of 38 questions in total, of which two were open-ended questions. Part A was about demographics and vessel characteristics, Part B about the fishing gear used by the participant fisher, Part C gathered general information about dolphin depredation, Part D about economic loss on fishing gear and catch due to dolphin depredation, and Part E about dolphin bycatch. The final section (Part F) of the interview focused on potential mitigation measures employed by fishers to reduce interactions with dolphins. An identification guide [67] illustrating the cetacean species found in the Mediterranean Sea was used during the interviews. With the help of the guide, fishers identified the species of dolphins likely to interact with their fishing gear. However, considering the potential uncertainty in species identification by fishers, we avoided strong conclusions on specific species responsible for causing depredation.

2.3. Data Treatment and Analysis

The data obtained from the interviews were divided by the two fishing fleet segments (SSF and LPF) and treated separately in most cases. Descriptive statistics such as means, percentages, standard deviation (SD), and minimum and maximum values were used to quantitatively analyze and describe the data. An interaction probability metric for each month of the year and fishing fleet segment was calculated based on a fishers’ score. The score was determined using an ordinal scale with four categories, as follows: No interaction; Low interaction; Medium interaction; High interaction. The scores were then transformed to a four-level numerical scale (0.00, 0.33, 0.67, and 1.00) and visualized using a ridgeline plot.
Based on the data gathered from the interviews, the interaction rate (IR) and bycatch rate (BR) were calculated as follows:
IR = Average annual days with dolphin interactions/Average annual fishing effort
IR is calculated as the average number of days per year with dolphin interactions divided by the average annual fishing effort. This represents the frequency of dolphin interactions relative to the total fishing activity over the course of a year.
BR = Total number of individuals bycaught/Years of in professional fishing
BR is calculated as the total number of individual dolphins bycaught divided by the total number of years in professional fishing. This represents the average number of individuals bycaught per year over the fisher’s career.
The ‘ggplot2’, ‘ggpubr’, ‘ggridges’, ‘hrbrthemes’ and ‘patchwork’ R packages (version 4.2.1) were used for data visualisation.

3. Results

3.1. Demographics of Fishers Interviewed

In total, 55 interviews were conducted with fishers from the SSF fleet segment and nine with fishers from the LPF fleet segment at 14 different ports. Twenty-four interviews were conducted in the Famagusta region, 17 in the Larnaca region, 5 in Limassol, and 18 in Paphos. (Figure 1). All the fishers interviewed were currently active in fishing, and the average age of SSF interviewed was 53 (SD: 14, range: 23–84), and of LPF was 50 (SD: 10, range: 33–63). On average, SSF and LPF had 26 (SD: 14, range: 3–50) and 24 (SD: 10, range: 6–50) years of experience, respectively. All the respondents were the boat owners except two LPF. Among all respondents, less than a fifth of them (n = 10) reported that fishing was not their only source of income. The average annual fishing days for SSF and LPF were 190 (SD: 44, range: 100–250) and 68 (SD: 6, range: 60–80) days, respectively.

3.2. Dolphin–Fisheries Interactions

All participants (SSF = 100%, LPF = 100%) reported that they have experienced dolphin depredation throughout their careers. When fishers were asked about the population status of dolphins in the last 10 years, 94% of SSF and 100% of LPF reported that “the population has been increased”, whereas few reported that “the population has remained the same” (4%) or that “did not know” (2%). The majority of fishers reported that “dolphin interactions have increased over the last 10 years” (SSF = 93%, LPF = 100%), whereas a minor percentage of SSF reported that “interactions have been remained the same” (7%). Among the SSF who have reported an “increase in dolphins’ interactions”, 7%, 47%, 25%, and 13% mentioned that interactions have increased by a quarter, doubled, tripled, and quadrupled, respectively. The majority of LPF mentioned that dolphin interactions have been tripled (78%) and the rest that have doubled (22%).
Participants were asked to report on the type of interaction that they experience when they encounter dolphins as well as other megafauna taxa (Table 1). None of the participants reported no interaction with dolphins, meaning that whenever they encounter dolphins, there is some type of interaction. Damage on catch and fishing gear and catch scattering by dolphins was reported more than 96% by all SSF and by 88.9% of all LPF. About half of LPF (55.6%) reported damage to fishing gear by dolphins. Interactions were also reported by other megafauna taxa, including turtles, the Mediterranean monk seal, puffer fish (Lagocephalus sceleratus), and elasmobranchs. Marine turtles, monk seals, and the puffer fish impacted primarily SSF compared to LPF, where elasmobranchs seem to have a low impact.
Four species of dolphins were identified by the participants to interact with fisheries. Common bottlenose dolphin (Tursiops truncatus) was unanimously reported by fishers (100%). Striped dolphins (Stenella coeruleoalba) were reported by 31% and 100% of SSF and LFP fishers, respectively. Rough-toothed dolphins (Steno bredanensis) were reported by more than 87% of the fishers. Risso’s dolphin (Grampus griseus) was reported by a small percentage (33%) of LPF fishers. The fishing gears mostly impacted by dolphin depredation were set nets (>65% of all responses) and the pelagic drifting longline (100% of all responses). Other fishing gear reported to be used by fishers (bottom longline, traps, vertical jigging, trolling) are not affected by the presence of dolphins and were not taken into consideration in the current study.
Fishers were asked to describe how they identify the damages caused to fishing gear by dolphins. The presence of dolphins in the area, the vocals of dolphins, and that when there is dolphin depredation, the heads of the fish are left on fishing gears were reported more than 78% by all participants. The damage caused to fishing gear was primarily reported by SSF (96%) and to a lesser extent by LPF (67%). The majority of LPF (89%) also reported that if the bait was missing from the pelagic longline when retrieving it and there was no catch, it is an indicator of dolphin depredation on the bait and not on the catch (Figure 2).
In order to understand the nature of the damages caused to fishing gear due to dolphin depredation, fishers were asked to describe the average net diameter area that is damaged per depredation attempt as well as the number of hooks damaged/lost per year in the case of the pelagic longline (Figure 3). The damaged areas on the nets were categorized into four size ranges: 0–30 cm, 30–80 cm, 80–120 cm, and >120 cm, and the frequency of occurrence for each category was calculated. Each participant could have selected more than one option. Almost all SSF fishers (86%) reported a net-damaged diameter area of 30–80 cm per depredation attempt, 70% reported a damaged area of 80–120 cm, and 55% reported 0–30 cm, whereas a minor percentage (6%) reported a damaged diameter area of more than 120 cm per depredation attempt. LPF reported an average number of hooks/branchlines damaged per year of 21 hooks (SD: 10, range: 10–40). The number of hooks set per fishing day is standard among pelagic longline fishers, and for albacore tuna fishing, it is about 4000 hooks and 800 for swordfish. The results also indicate an average loss of 0.3 hooks/branchlines per fishing day per fisher. In regards to which depths dolphin interactions are more likely to occur, for the case of SSF interactions, they are more intense between 0 and 100 m (100%), and for the case of LPF (100%) at depths of greater than 100 m depth. A few LPF (44%) also reported dolphin interactions up to 100 m depth.
The interaction probability between dolphins and fishing activities throughout the different months of the year for the two fishing fleets is shown in Figure 4. In general, the interaction probability was always above 0 for SSF fishers, indicating a constant dolphin–fisheries interaction throughout the year. For SSF fishers, a high dolphin interaction period was recorded between March and May, a moderate interaction probability between June and October, and a low interaction probability between November and January. For LPF fishers, the highest interaction probability was recorded between May and August, moderate interaction between September and November, and low interaction during December. Between January and March there was no interaction for LPF fishers, as the pelagic longline fishery is not active during those months due to ICCAT and EU rules. April is usually an inactive month, even though fishing with drifting pelagic longlines is allowed.
To better understand the interaction probability across the different months, fishers were also asked to report during which targeted fishing periods interactions with dolphins are more intense. Four targeted fishing periods were reported by fishers; these were the picarel (SSF = 95%), blotched picarel (SSF = 91%), the bogue (SSF = 100%), and the albacore tuna (LPF = 100%). The picarel, blotched picarel, and bogue are fished during winter–spring, and the albacore tuna is fished during late spring–summer, starting from mid-to-end of May, depending on the year. A list of species that are more likely to be affected by dolphin depredation was prepared according to their responses as well as the number of times each species was reported (Table 2).
The average days per year with dolphin interactions were 44 days (SD: 22 days, range: 10–90 days) for the SSF segment and 42 days (SD: 6, range: 30–50) for the LPF segment. Based on that, the dolphin interaction rate was calculated. On average, the dolphin interaction rate for SSF was 0.2 (SD: 0.1, range: 0.1–0.7) and 0.6 (SD: 0.1, range: 0.5–0.7) for LPF, indicating that dolphin interactions occur at approximately a quarter of the total fishing days for SSF and more than half for LPF per year per vessel (Figure 5). Fishers clarified that in all cases, dolphin interactions led to depredation.
Dolphin bycatch has been reported by almost a quarter (22%) of SSF and by all LPF fishers. The bycatch of the common bottlenose dolphin has been reported by 22% of SSF fishers and by all (100%) LPF fishers. The striped dolphin has been reported only by 22% of LPF fishers. Among the 15 individual dolphins that were reported as bycatch on the SSF segment, 7 (47%) were juveniles, and 5 (33%) were released alive. In the case of the LPF segment, 45 individual dolphins were reported as bycatch, of which 15 (33%) were juveniles and 31 (69%) were released alive. The average bycatch rate per year per vessel was estimated at 0.01 (SD: 0.02, range: 0–0.09) and 0.18 (SD: 0.14, range: 0.04–0.42) for SSF and LPF, respectively (Figure 5). The participants indicated that the common practice among all fishers is to release the animals alive back into the sea, and no evidence of intentional killing was reported.

3.3. Economic Loss on Catch and Fishing Gear

The average economic loss per year on catch was EUR 3565 (SD: 2076, range: 200–9000) and EUR 28,160 (SD: 3389, range: 17,250–36,750) for SSF and LPF, respectively. In regards to the economic loss on fishing gear, the average loss per year was EUR 2578 (SD: 1726, range: 100–9000) and EUR 1722 (SD: 667, range: 1000–3000) for SSF and LPF, respectively (Figure 6). Consequently, the total economic loss per year, including catch loss and fishing gear damages, was EUR 6144 (SD: 3803) and 29,882 (SD: 6809) for SSF and LPF, respectively. The results also showed that in the case of LPF, the main economic loss was on catch and not on fishing gear.

3.4. Fishers’ Perception and Attitude Towards Dolphin–Fisheries Interactions Mitigation Measures

The majority of both SSF (60%) and LPF (78%) take some kind of measures, while the rest (SSF: 40%, LPF: 22%) did not take any measures. The most frequent measures taken were the use of dolphin acoustic deterrent devices (SSF: 26%, LPF: 44%), also known as ‘pingers’ among fishers; the use of handmade guns (SSF: 42%, LPF: 33%); avoiding going fishing during times when the presence of dolphins is very high (SSF: 4%, LPF: 11%); and changing fishing locations (SSF: 2%, LPF: 22%).
A few SSF (15%) and the majority of LPF (78%) recommended pingers as the only possible mitigation measure for dolphin interactions, while the rest believed that there is no possible solution to the problem (SSF: 86%, LPF: 22%). The majority of SSF (98%) and all of LPF (100%) were aware of the dolphin acoustic deterrent devices. A total of 60% of SSF and 22% of LPF declared that they have never used pingers in their careers. From the rest who did use or were still using pingers, they mentioned the “DDD” (SSF: 13%, LPF: 33%) and “DiD” (SSF: 24%, LPF: 44%) models from the manufacturer STM Ltd. (Tring, Italy) and the “banana pinger” (SSF: 24%) from the manufacturer Fishtek Marine (Totnes, UK). The DDD (Dolphin Deterrent Device) is an ultra-frequency pinger and is activated automatically when in contact with water and emits a continuous sound, whereas the DiD (Dolphin Interactive Deterrent) is the interactive model of the DDD, and it operates only when it detects the presence of the dolphins in the area by receiving the dolphins’ clicks.
Among the fishers who mentioned using pingers, 20% reported regular use and 25% that they were using them in the past. About 19% of them were not satisfied by the use of pingers, and 14% were satisfied; one fisher (2%) was not willing to try, and 67% of them were willing to try them. Fishers were then asked to state the reason for their opinion of pinger use. Only 16% of fishers considered pingers effective and 22% ineffective, whereas 45% of them considered them too expensive, and about 5% could not clarify the reason for their response. The percentage and network of responses are presented via an alluvial diagram in Figure 7.

4. Discussion

The study provides a comprehensive examination of interactions between dolphins and two fishing fleet segments within Cypriot waters, addressing both the socio-economic impacts on fishers and potential conservation challenges posed by these interactions. By utilizing fishers’ ecological knowledge (FEK) as a primary data source, the study captures unique insights into the dynamics of dolphin depredation, economic losses, and fishers’ perceptions of mitigation measures, providing a nuanced understanding of human–wildlife conflicts in marine environments.
The results revealed that dolphin interactions were consistently high across both small-scale (SSF) and large pelagic (LPF) fleet segments in Cyprus but with low bycatch probability. Low dolphin bycatch rate was also reported across all Mediterranean regions. However, this was not always the case. The intense use of driftnets, which began in the 1980s targeting swordfish and albacore tuna, was responsible for high bycatch and mortality of cetaceans [20,68,69,70]. Despite the low bycatch rate recorded in the present study, about one-fourth of all fishers reported experiencing at least one dolphin bycatch in their careers, which remains an alarming finding. This aligns with patterns observed in other Mediterranean regions where common bottlenose dolphins, known for their opportunistic feeding habits, frequently engage with fisheries in coastal waters targeting high-value fish species [22,23,35,56,71]. The reported increase in dolphin interactions aligns with previous findings in other regions of the Mediterranean, suggesting a broader trend of marine mammals adapting their foraging behavior to exploit fisheries. This phenomenon is facilitated by the high adaptability, learning capabilities, and cognitive skills of dolphin species, allowing them to optimize energy expenditure by targeting fishing operations [25,26,31,37,38,39,40]. The mutual overlap of target species and fishing areas between dolphins and fishers exacerbated the competition, highlighting the need for sustainable coexistence strategies.
The dolphin species reported by fishers to interact with fishing operations have been previously reported in the Cypriot waters [72]. Although the common bottlenose dolphin, striped dolphin, and Risso’s dolphin have been previously reported to interact with fisheries in the Mediterranean [19], the rough-toothed dolphin has never been reported before. It is likely that fishers of the study may have confused the rough-toothed dolphin with the common bottlenose dolphin and ‘blamed’ the common bottlenose dolphin for causing depredation on the pelagic longline fishery. However, the rough-toothed dolphin has been reported in the Levantine Sea with the highest frequency of sightings compared to other Mediterranean regions [73]. A recent study [74] published in 2023 reported a stranded rough-toothed dolphin on the northern coast of Cyprus, found with plastic lures in its stomach. The reported plastic lures are currently used by the LPF during the swordfish fishing period, which highlights the potential negative impact of depredation and the use of artificial bait on dolphin mortality.
The persistence of dolphin interactions over the past decade, with a perceived increase reported by 93% of SSF and 100% of LPF, suggests a growing habituation among dolphins to fishing activities as a reliable food source. Prior studies, including those in other Mediterranean regions like Sardinia [1,9,32], corroborate this trend of dolphins adapting their foraging behaviors to capitalize on human fishing efforts. Such behavioral plasticity in dolphins, supported by their advanced cognitive abilities, likely contributes to the observed interaction rates and complicates mitigation efforts. However, attention should be given to the estimates provided by fishers regarding dolphin population trends, as an increase in the frequency of interactions does not directly imply an increase in dolphin population. An increase in depredation events may be due to an increase in fishing effort in days and fishing gear used, depleted biological resources, and resource overlap, or a combination of factors that requires further examination [18,20,75,76,77].
The findings also showed that fishers were able to identify and differentiate the damages caused to fishing gear and catch by dolphins compared to other megafauna species. In most cases, dolphin depredation is confirmed by the presence and vocals of dolphins, as fishers indicated. For the SSF fleet segment, damage to set nets caused by dolphins is distinguishable by the size of the holes, which tends to be larger compared to those caused by monk seals [57] or puffer fish. In the LPF fleet segment, dolphin depredation is indicated by the type of damage inflicted on the catch (Figure 3D) as well as the removal of bait [29].
The interaction probability suggests constant dolphin–fisheries interactions through the year. For the SSF fleet segment, the highest interaction probability was recorded during winter and spring months, which aligns with the targeted fisheries of picarel, blotched picarel, and bogue. In contrast, the highest interaction probability for the LPF fleet segment was recorded during the summer months, coinciding with the albacore tuna fishing season. The list of species provided in Table 2 also shows that the preferred species by dolphins are among the highly commercial and prized species. LPF fishers also reported dolphin depredation on swordfish. It is important to note that depredation on swordfish by cetaceans has not been previously reported in the literature. However, it is theoretically possible that dolphins may target juvenile (undersized) swordfish, though this hypothesis requires further investigation. Many SSF fishers reported during interviews that they wait each year for the albacore tuna fishing period to begin as it drives dolphins offshore towards the pelagic longline fishery, providing them a temporary reprieve from dolphin depredation. The findings suggest that dolphins may exhibit a partial reliance on Cyprus fisheries as part of their foraging strategy [41]. Similarly, fishers from the Italian Adriatic Sea reported that during the closure period for bottom trawls, dolphins move towards the coastal areas depredating on set nets [23]. However, further research on dolphin population dynamics is required to confirm this statement.
A visual and passive acoustic survey conducted in August and November 2016 and in May 2017 recorded four species of dolphins and one species of whale in Cypriot waters [72]. These were the common bottlenose dolphin, striped dolphin, rough-toothed dolphin, Risso’s dolphin, and the sperm whale. The study confirmed the coastal preference of the common bottlenose dolphin and reported sightings of groups between 5 and 15 individuals found in waters less than 500 m depth and as close as 1.6 km from the shore. The sightings were recorded only during the May survey. The study also mentioned reports from fishers regarding dolphin depredation but did not confirm the dolphin species interacting with each fishing gear type. Striped dolphins were the most commonly recorded species in the study, as they were recorded in all surveys and in large groups ranging from 10 to 60 individuals. The species was recorded in both coastal and offshore waters, ranging between 400 m and 2500 m in depth and between 4 and 50 nautical miles from the nearest shore. During the November survey, the species was recorded near the coast, and during the May and August surveys, it was recorded in offshore waters, overlapping with the albacore tuna fishing period. The Risso’s dolphin was recorded in May in offshore waters deeper than 1000 m in a group of 15 individuals. Finally, the rough-toothed dolphin was recorded only during the May survey in offshore waters deeper than 1000 m depth. The species was recorded in a mixed group with striped dolphins and, on another occasion, with the Risso’s dolphins, suggesting that this species may form fission–fusion grouping with other species in the region. The findings of the study also suggested a summer peak of this species [72]. Given the above information and known ecological characteristics of these species, it is likely that the common bottlenose dolphin is the species that interacts with set nets (SSF fleet segment) and the rough-toothed and Risso’s dolphins with the drifting pelagic longline during albacore tuna and swordfish fishing periods (LPF fleet segment). The striped dolphin probably interacts with both coastal and offshore fisheries [72].
The economic pressures exerted by dolphin depredation underscore a complex socioeconomic dimension. For SSF, where fishing often represents the primary income source, sustained depredation risks threaten livelihood stability, potentially exacerbating existing social tensions. The reliance on fisheries in coastal communities makes dolphin interactions a point of contention, particularly when losses reach thousands of euros annually. In this context, the economic loss reported by other studies in the Mediterranean Sea due to dolphin depredation [3,6,7,9,13,22,23,29,30,56,71,78] lay from EUR 500 to 20,000 EUR per vessel and year. In the present study, according to fishers’ statements, SSF fishers and LPF fishers incurring annual losses of approximately EUR 6144 and EUR 29,882, respectively. Interestingly, the primary economic burden for LPF fishers was observed in catch loss rather than gear damage, contrasting with the SSF fishers, where gear damage was equally significant. Although the estimated economic loss on catches for LPF is EUR 28,160 (excluding loss on fishing gear), which may initially appear high and unrealistic, it is not without basis. According to official country data (pers. comm. Fisheries Office), the total landings of albacore tuna by LPF in 2023 were 345,324 kg by the 20 active vessels. With an average price of about EUR 2.3 per kilogram, each vessel generated an average income of EUR 39,712 (345,324 kg / 20 vessels × EUR 2.3 per kilogram). Given that the current study identified depredation occurring at about half of the LPF fishing days, the estimated economic loss appears plausible. However, reports from fishers regarding economic losses should be interpreted with caution until further field studies are conducted to validate these findings. These results underscore the need for tailored mitigation strategies that address the distinct impacts experienced by each fleet segment.
The fishers’ preference for acoustic deterrent devices (pingers) and their use of more traditional deterrents, such as creating noise with handmade guns, reflects both a willingness to mitigate losses and a gap in accessible, effective solutions. The handmade gun used by fishers is a metallic pipe, operated with normal hunting cartridges, and its only purpose is to create a strong sound from the shooting in order to drive dolphins away. The shooting is normally happening underwater at a random position. Even though the purpose of this practice is to scare dolphins away, it is unknown if it harms dolphins or any other marine life in any way. The results also indicated that the most commonly used pingers are the ones manufactured by STM Ltd. Several case studies showed positive results in the reduction in dolphins’ presence and depredation by using the DDDs pingers [79]. Most fishers deemed the “banana pinger” ineffective, explaining that after prolonged use, dolphins became familiar with the sound and resumed interacting with the fishing gear. In some cases, the device had the opposite effect, by attracting dolphins to the fishing gear. The mixed efficacy of pingers, as reported, suggests habituation by dolphins to these deterrents, raising questions about their long-term viability. Studies have shown that dolphins can quickly adapt to repetitive stimuli, which may explain the variable success rates observed in this study [79,80].
Additionally, the willingness of LPF and SSF fishers to adopt mitigation strategies like pingers indicates openness to non-lethal solutions, despite the reported limitations. This interest in non-lethal methods suggests that with further development and cost-effective distribution of more advanced pingers, compliance could be high. This finding also supports initiatives that involve fishers in the development and testing phases of deterrents, enhancing user acceptance and potentially increasing efficacy. Also, the variety in fishers’ responses regarding the use of pingers as a mitigation tool indicates a gap in their knowledge and understanding of the proper use of pingers. Tailored-made training programs regarding the different types of pingers available in the market and their correct application could help improve acceptance and usage by the fishing sector. The study calls for further research into adaptive mitigation strategies that can accommodate both ecological and socio-economic concerns.
While this study contributes valuable insights into dolphin–fisheries interactions in Cyprus, several knowledge gaps remain. First, the ecological dynamics driving dolphins’ increased interaction with fisheries require further exploration. Future research could examine the extent to which shifts in fish populations, potentially influenced by climate change or overfishing, are altering dolphin foraging patterns and thereby intensifying interactions with fisheries. Long-term monitoring of dolphin populations and their behavior around fishing areas can contribute valuable insights into mitigating dolphin depredation in a manner that minimizes economic burdens on fishers. Additionally, studies that assess the long-term behavioral changes in dolphin populations exposed to acoustic deterrents would inform the development of adaptive management practices. Furthermore, visualization of the fishing activities in order to depict “hot” and “cold” zones of the albacore fishing activities would provide additional information on potential high dolphin conflict areas.
Moreover, the economic analysis presented here could be expanded through longitudinal studies that monitor financial losses across seasons, fishing efforts, fishing gear, and varying levels of dolphin presence. Incorporating broader socioeconomic metrics, such as community dependency on fisheries income and the psychological impact of sustained depredation, would provide a more holistic understanding of the issue. Additionally, investigating the socio-cultural factors that influence fishers’ acceptance and use of mitigation measures could enhance the effectiveness of such tools and reduce conflicts with conservation policies. Lastly, testing alternative deterrent devices in collaboration with fishers can yield data on potential advancements, especially in minimizing habituation to existing deterrent technologies.

5. Conclusions

This study underscores the significant and multifaceted challenges posed by dolphin depredation on Cypriot fisheries, both economically and socially. High interaction rates, gear damage, and catch loss represent not only financial setbacks but also indicate a complex ecological interaction between dolphins and fishing practices. The persistence of these interactions, coupled with the mixed efficacy of deterrent measures, highlights the need for improved, species-specific mitigation technologies and suggests that collaborative approaches involving fishers may yield more sustainable solutions. Future research should continue to explore ecological drivers, economic impacts, and innovative deterrent methods to better support conservation and fishery management goals.

Author Contributions

Conceptualization, M.P.; methodology, M.P.; formal analysis, M.P.; investigation, M.P. and C.C.; resources, A.P.; data curation, M.P.; writing—original draft preparation, M.P. and D.K.M.; writing—review and editing, D.K.M., S.-I.H. and A.P.; visualization, M.P.; supervision, M.P.; project administration, S.-I.H.; funding acquisition, A.P. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the European Maritime, Fisheries and Aquaculture Fund (EMFAF) and national resources, grant number UCY-2020-058-ΩΚ.

Institutional Review Board Statement

All necessary permits were obtained for the described field studies. Interviewees were informed of the purpose of the study and told that the data collected were confidential and that their anonymity would be protected according to the Regulation (EU) 2016/679. The interviews were carried out only after fishermen verbally consented to participate.

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

Data are available upon reasonable request to the authors.

Acknowledgments

The authors would like to deeply thank all fishers who have participated in the study and shared their valuable time, knowledge and experience. This work forms part of the requirements for the Doctor of Philosophy degree by the first author.

Conflicts of Interest

Soteria-Irene Hadjieftychiou, Chistodoulos Christodoulou and Antonis Petrou were employed by AP Marine Environmental Consaltuncy. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

References

  1. Díaz López, B. Interactions between Mediterranean Bottlenose Dolphins (Tursiops truncatus) and Gillnets off Sardinia, Italy. ICES J. Mar. Sci. 2006, 63, 946–951. [Google Scholar] [CrossRef]
  2. Dalla Rosa, L.; Secchi, E.R. Killer Whale (Orcinus orca) Interactions with the Tuna and Swordfish Longline Fishery off Southern and South-Eastern Brazil: A Comparison with Shark Interactions. J. Mar. Biol. Ass. 2007, 87, 135–140. [Google Scholar] [CrossRef]
  3. Brotons, J.M.; Grau, A.M.; Rendell, L. Estimating the Impact of Interactions between Bottlenose Dolphins and Artisanal Fisheries around the Balearic Islands. Mar. Mammal Sci. 2008, 24, 112–127. [Google Scholar] [CrossRef]
  4. Forney, K.A.; Kobayashi, D.R.; Johnston, D.W.; Marchetti, J.A.; Marsik, M.G. What’s the Catch? Patterns of Cetacean Bycatch and Depredation in Hawaii-based Pelagic Longline Fisheries. Mar. Ecol. 2011, 32, 380–391. [Google Scholar] [CrossRef]
  5. Hamer, D.J.; Childerhouse, S.J.; Gales, N.J. Odontocete Bycatch and Depredation in Longline Fisheries: A Review of Available Literature and of Potential Solutions. Mar. Mammal Sci. 2012, 28, E345–E374. [Google Scholar] [CrossRef]
  6. Maccarrone, V.; Buffa, G.; Di Stefano, V.; Filiciotto, F.; Mazzola, S.; Buscaino, G. Economic Assessment of Dolphin Depredation Damages and Pinger Use in Artisanal Fisheries in the Archipelago of Egadi Islands (Sicily). Turk. J. Fish. Aquat. Sci. 2014, 14, 173–181. [Google Scholar] [CrossRef]
  7. Gonzalvo, J.; Giovos, I.; Moutopoulos, D.K. Fishermen’s Perception on the Sustainability of Small-scale Fisheries and Dolphin–Fisheries Interactions in Two Increasingly Fragile Coastal Ecosystems in Western Greece. Aquat. Conserv. 2015, 25, 91–106. [Google Scholar] [CrossRef]
  8. Guinet, C.; Tixier, P.; Gasco, N.; Duhamel, G. Long-Term Studies of Crozet Island Killer Whales Are Fundamental to Understanding the Economic and Demographic Consequences of Their Depredation Behaviour on the Patagonian Toothfish Fishery. ICES J. Mar. Sci. 2015, 72, 1587–1597. [Google Scholar] [CrossRef]
  9. Lauriano, G.; Fortuna, C.M.; Moltedo, G.; Notarbartolo Di Sciara, G. Interactions between Common Bottlenose Dolphins (Tursiops truncatus) and the Artisanal Fishery in Asinara Island National Park (Sardinia): Assessment of Catch Damage and Economic Loss. JCRM 2023, 6, 165–173. [Google Scholar] [CrossRef]
  10. Neil, D.T. Cooperative Fishing Interactions between Aboriginal Australians and Dolphins in Eastern Australia. Anthrozoös 2002, 15, 3–18. [Google Scholar] [CrossRef]
  11. Peterson, D.; Hanazaki, N.; Simões-Lopes, P.C. Natural Resource Appropriation in Cooperative Artisanal Fishing between Fishermen and Dolphins (Tursiops truncatus) in Laguna, Brazil. Ocean Coast. Manag. 2008, 51, 469–475. [Google Scholar] [CrossRef]
  12. D’Lima, C.; Marsh, H.; Hamann, M.; Sinha, A.; Arthur, R. Positive Interactions Between Irrawaddy Dolphins and Artisanal Fishers in the Chilika Lagoon of Eastern India Are Driven by Ecology, Socioeconomics, and Culture. AMBIO 2014, 43, 614–624. [Google Scholar] [CrossRef] [PubMed]
  13. Bearzi, G.; Holcer, D.; Notarbartolo Di Sciara, G. The Role of Historical Dolphin Takes and Habitat Degradation in Shaping the Present Status of Northern Adriatic Cetaceans. Aquat. Conserv. 2004, 14, 363–379. [Google Scholar] [CrossRef]
  14. Zollet, E.A.; Read, A.J. Depredation of Catch by Bottlenose Dolphins (Tursiops truncatus) in the Florida King Mackerel (Scomberomorus Cavalla) Troll Fishery. Fish. Bull. 2006, 104, 343–349. [Google Scholar]
  15. Harwood, J. Assessing the Competitive Effects of Marine Mammal Predation on Commercial Fisheries. S. Afr. J. Mar. Sci. 1992, 12, 689–693. [Google Scholar] [CrossRef]
  16. Read, A.J. The Looming Crisis: Interactions between Marine Mammals and Fisheries. J. Mammal. 2008, 89, 541–548. [Google Scholar] [CrossRef]
  17. Nelms, S.; Alfaro-Shigueto, J.; Arnould, J.; Avila, I.; Bengtson Nash, S.; Campbell, E.; Carter, M.; Collins, T.; Currey, R.; Domit, C.; et al. Marine Mammal Conservation: Over the Horizon. Endanger. Species Res. 2021, 44, 291–325. [Google Scholar] [CrossRef]
  18. Jog, K.; Sutaria, D.; Diedrich, A.; Grech, A.; Marsh, H. Marine Mammal Interactions With Fisheries: Review of Research and Management Trends Across Commercial and Small-Scale Fisheries. Front. Mar. Sci. 2022, 9, 758013. [Google Scholar] [CrossRef]
  19. Gonzalvo, J.; Carpentieri, P. Depredation by Marine Mammals in Fishing Gear; Studies and Reviews; FAO: Rome, Italy, 2023; p. 56. [Google Scholar]
  20. Carpentieri, P.; Nastasi, A.; Sessa, M.; Scour, A. Incidental Catch of Vulnerable Species in Mediterranean and Black Sea Fisheries—A Review; Studies and Reviews; FAO: Rome, Italy, 2021; ISBN 978-92-5-134631-0. [Google Scholar]
  21. Read, A.J.; Drinker, P.; Northridge, S. Bycatch of Marine Mammals in U.S. and Global Fisheries. Conserv. Biol. 2006, 20, 163–169. [Google Scholar] [CrossRef]
  22. Revuelta, O.; Domènech, F.; Fraija-Fernández, N.; Gozalbes, P.; Novillo, O.; Penadés-Suay, J.; Tomás, J. Interaction between Bottlenose Dolphins (Tursiops truncatus) and Artisanal Fisheries in the Valencia Region (Spanish Mediterranean Sea). Ocean Coast. Manag. 2018, 165, 117–125. [Google Scholar] [CrossRef]
  23. Li Veli, D.; Petetta, A.; Barone, G.; Ceciarini, I.; Franchi, E.; Marsili, L.; Pietroluongo, G.; Mazzoldi, C.; Holcer, D.; D’Argenio, S.; et al. Fishers’ Perception on the Interaction between Dolphins and Fishing Activities in Italian and Croatian Waters. Diversity 2023, 15, 133. [Google Scholar] [CrossRef]
  24. Reeves, R.; McClellan, K.; Werner, T. Marine Mammal Bycatch in Gillnet and Other Entangling Net Fisheries, 1990 to 2011. Endanger. Species Res. 2013, 20, 71–97. [Google Scholar] [CrossRef]
  25. Goetz, S.; Read, F.L.; Santos, M.B.; Pita, C.; Pierce, G.J. Cetacean–Fishery Interactions in Galicia (NW Spain): Results and Management Implications of a Face-to-Face Interview Survey of Local Fishers. ICES J. Mar. Sci. 2014, 71, 604–617. [Google Scholar] [CrossRef]
  26. Goetz, S.; Read, F.L.; Ferreira, M.; Portela, J.M.; Santos, M.B.; Vingada, J.; Siebert, U.; Marçalo, A.; Santos, J.; Araújo, H.; et al. Cetacean Occurrence, Habitat Preferences and Potential for Cetacean–Fishery Interactions in Iberian Atlantic Waters: Results from Cooperative Research Involving Local Stakeholders. Aquat. Conserv. 2015, 25, 138–154. [Google Scholar] [CrossRef]
  27. Wise, L.; Silva, A.; Ferreira, M.; Silva, M.A.; Sequeira, M. Interactions between Small Cetaceans and the Purse-Seine Fishery in Western Portuguese Waters. Sci. Mar. 2007, 71, 405–412. [Google Scholar] [CrossRef]
  28. Marçalo, A.; Katara, I.; Feijó, D.; Araújo, H.; Oliveira, I.; Santos, J.; Ferreira, M.; Monteiro, S.; Pierce, G.J.; Silva, A.; et al. Quantification of Interactions between the Portuguese Sardine Purse-Seine Fishery and Cetaceans. ICES J. Mar. Sci. 2015, 72, 2438–2449. [Google Scholar] [CrossRef]
  29. Papageorgiou, M.; Hadjioannou, L.; Jimenez, C.; Georgiou, A.; Petrou, A. Understanding the Interactions Between Cetaceans and Other Megafauna With the Albacore Tuna Fishery: A Case Study From the Cyprus’ Pelagic Longline Fishery. Front. Mar. Sci. 2022, 9, 868464. [Google Scholar] [CrossRef]
  30. Alexandre, S.; Marçalo, A.; Marques, T.A.; Pires, A.; Rangel, M.; Ressurreição, A.; Monteiro, P.; Erzini, K.; Gonçalves, J.M. Interactions between Air-Breathing Marine Megafauna and Artisanal Fisheries in Southern Iberian Atlantic Waters: Results from an Interview Survey to Fishers. Fish. Res. 2022, 254, 106430. [Google Scholar] [CrossRef]
  31. Giménez, J.; Marçalo, A.; Ramírez, F.; Verborgh, P.; Gauffier, P.; Esteban, R.; Nicolau, L.; González-Ortegón, E.; Baldó, F.; Vilas, C.; et al. Diet of Bottlenose Dolphins (Tursiops truncatus) from the Gulf of Cadiz: Insights from Stomach Content and Stable Isotope Analyses. PLoS ONE 2017, 12, e0184673. [Google Scholar] [CrossRef]
  32. Lauriano, G.; Caramanna, L.; Scarnò, M.; Andaloro, F. An Overview of Dolphin Depredation in Italian Artisanal Fisheries. J. Mar. Biol. Assoc. 2009, 89, 921–929. [Google Scholar] [CrossRef]
  33. Bearzi, G.; Piwetz, S.; Reeves, R.R. Odontocete Adaptations to Human Impact and Vice Versa. In Ethology and Behavioral Ecology of Odontocetes; Würsig, B., Ed.; Ethology and Behavioral Ecology of Marine Mammals; Springer International Publishing: Cham, Switzerland, 2019; pp. 211–235. ISBN 978-3-030-16662-5. [Google Scholar]
  34. Blanco, C.; Salomón, O.; Raga, J.A. Diet of the Bottlenose Dolphin (Tursiops truncatus) in the Western Mediterranean Sea. J. Mar. Biol. Assoc. 2001, 81, 1053–1058. [Google Scholar] [CrossRef]
  35. Pardalou, A.; Tsikliras, A.C. Factors Influencing Dolphin Depredation in Coastal Fisheries of the Northern Aegean Sea: Implications on Defining Mitigation Measures. Mar. Mammal Sci. 2020, 36, 1126–1149. [Google Scholar] [CrossRef]
  36. Santos, M.B.; Fernández, R.; López, A.; Martínez, J.A.; Pierce, G.J. Variability in the Diet of Bottlenose Dolphin, Tursiops truncatus, in Galician Waters, North-Western Spain, 1990–2005. J. Mar. Biol. Assoc. 2007, 87, 231–241. [Google Scholar] [CrossRef]
  37. Whitehead, H.; Rendell, L.; Osborne, R.W.; Würsig, B. Culture and Conservation of Non-Humans with Reference to Whales and Dolphins: Review and New Directions. Biol. Conserv. 2004, 120, 427–437. [Google Scholar] [CrossRef]
  38. Gilman, E.; Brothers, N.; McPherson, G.; Dalzell, P. A Review of Cetacean Interactions with Longline Gear. JCRM 2006, 8, 215–223. [Google Scholar] [CrossRef]
  39. Bearzi, G.; Reeves, R.R. Marine Mammals Foraging around Fishing Gear or Preying upon Fishing Catch and Bait: It May Not Be “Depredation”. ICES J. Mar. Sci. 2022, 79, 2178–2183. [Google Scholar] [CrossRef]
  40. Pennino, M.G.; Rotta, A.; Pierce, G.J.; Bellido, J.M. Interaction between Bottlenose Dolphin (Tursiops truncatus) and Trammel Nets in the Archipelago de La Maddalena, Italy. Hydrobiologia 2014, 747, 69–82. [Google Scholar] [CrossRef]
  41. Louise Chilvers, B.; Corkeron, P.J. Trawling and Bottlenose Dolphins’ Social Structure. Proc. R. Soc. Lond. B 2001, 268, 1901–1905. [Google Scholar] [CrossRef]
  42. Pennino, M.G.; Mendoza, M.; Pira, A.; Floris, A.; Rotta, A. Assessing Foraging Tradition in Wild Bottlenose Dolphins (Tursiops truncatus). Aquat. Mamm. 2013, 39, 282–289. [Google Scholar] [CrossRef]
  43. Sacchi, J. Overview of Mitigation Measures to Reduce the Incidental Catch of Vulnerable Species in Fisheries, 1st ed.; Studies and Reviews; FAO: Rome, Italy, 2021; ISBN 978-92-5-134539-9. [Google Scholar]
  44. Goodson, A.D. Developing Deterrent Devices Designed to Reduce the Mortality of Small Cetaceans in Commercial Fishing Nets. Mar. Freshw. Behav. Physiol. 1997, 29, 211–236. [Google Scholar] [CrossRef]
  45. Kraus, S.D.; Read, A.J.; Solow, A.; Baldwin, K.; Spradlin, T.; Anderson, E.; Williamson, J. Acoustic Alarms Reduce Porpoise Mortality. Nature 1997, 388, 525. [Google Scholar] [CrossRef]
  46. Wu, H.; Li, Q.; Wang, C.; Wu, Q.; Peng, C.; Jefferson, T.A.; Long, Z.; Luo, F.; Xu, Y.; Huang, S.-L. Bycatch Mitigation Requires Livelihood Solutions, Not Just Fishing Bans: A Case Study of the Trammel-Net Fishery in the Northern Beibu Gulf, China. Mar. Policy 2022, 139, 105018. [Google Scholar] [CrossRef]
  47. Dalpaz, L.; Daura-Jorge, F.G.; Lewison, R.; Zank, S.; Hanazaki, N. Fishers’ Perception and Activity Shifts in a Dolphin Bycatch Mitigation Context. Ocean Coast. Manag. 2024, 258, 107375. [Google Scholar] [CrossRef]
  48. Abbott, J.K.; Haynie, A.C. What Are We Protecting? Fisher Behavior and the Unintended Consequences of Spatial Closures as a Fishery Management Tool. Ecol. Appl. 2012, 22, 762–777. [Google Scholar] [CrossRef]
  49. Cohen, P.J.; Allison, E.H.; Andrew, N.L.; Cinner, J.; Evans, L.S.; Fabinyi, M.; Garces, L.R.; Hall, S.J.; Hicks, C.C.; Hughes, T.P.; et al. Securing a Just Space for Small-Scale Fisheries in the Blue Economy. Front. Mar. Sci. 2019, 6, 171. [Google Scholar] [CrossRef]
  50. Lewison, R.L.; Johnson, A.F.; Verutes, G.M. Embracing Complexity and Complexity-Awareness in Marine Megafauna Conservation and Research. Front. Mar. Sci. 2018, 5, 207. [Google Scholar] [CrossRef]
  51. Komoroske, L.M.; Lewison, R.L. Addressing Fisheries Bycatch in a Changing World. Front. Mar. Sci. 2015, 2, 83. [Google Scholar] [CrossRef]
  52. Suuronen, P. Understanding Perspectives and Barriers That Affect Fishers’ Responses to Bycatch Reduction Technologies. ICES J. Mar. Sci. 2022, 79, 1015–1023. [Google Scholar] [CrossRef]
  53. Barclay, K.; Voyer, M.; Mazur, N.; Payne, A.M.; Mauli, S.; Kinch, J.; Fabinyi, M.; Smith, G. The Importance of Qualitative Social Research for Effective Fisheries Management. Fish. Res. 2017, 186, 426–438. [Google Scholar] [CrossRef]
  54. Wedemeyer-Strombel, K.R.; Peterson, M.J.; Sanchez, R.N.; Chavarría, S.; Valle, M.; Altamirano, E.; Gadea, V.; Sowards, S.K.; Tweedie, C.E.; Liles, M.J. Engaging Fishers’ Ecological Knowledge for Endangered Species Conservation: Four Advantages to Emphasizing Voice in Participatory Action Research. Front. Commun. 2019, 4, 30. [Google Scholar] [CrossRef]
  55. Papageorgiou, M.; Tourapi, C.; Nikolaidis, G.; Petrou, A.; Moutopoulos, D.K. Profiling the Cypriot Fisheries Sector through the Lens of Fishers: A Participatory Approach between Fishers and Scientists. Fishes 2024, 9, 308. [Google Scholar] [CrossRef]
  56. Snape, R.T.E.; Broderick, A.C.; Çiçek, B.A.; Fuller, W.J.; Tregenza, N.; Witt, M.J.; Godley, B.J. Conflict between Dolphins and a Data-Scarce Fishery of the European Union. Hum. Ecol. 2018, 46, 423–433. [Google Scholar] [CrossRef]
  57. Papageorgiou, M.; Karonias, A.; Eftychiou, A.; Hadjioannou, L. Understanding the Interactions between Small-Scale Fisheries and the Mediterranean Monk Seal Using Fishermen’s Ecological Knowledge. Animals 2023, 13, 2164. [Google Scholar] [CrossRef] [PubMed]
  58. Lin, M.; Xing, L.; Fang, L.; Huang, S.-L.; Yao, C.-J.; Turvey, S.T.; Gozlan, R.E.; Li, S. Can Local Ecological Knowledge Provide Meaningful Information on Coastal Cetacean Diversity? A Case Study from the Northern South China Sea. Ocean Coast. Manag. 2019, 172, 117–127. [Google Scholar] [CrossRef]
  59. Carter, B.T.G.; Nielsen, E.A. Exploring Ecological Changes in Cook Inlet Beluga Whale Habitat Though Traditional and Local Ecological Knowledge of Contributing Factors for Population Decline. Mar. Policy 2011, 35, 299–308. [Google Scholar] [CrossRef]
  60. Wilson, D.C.; Raakjær, J.; Degnbol, P. Local Ecological Knowledge and Practical Fisheries Management in the Tropics: A Policy Brief. Mar. Policy 2006, 30, 794–801. [Google Scholar] [CrossRef]
  61. Bevilacqua, A.H.V.; Carvalho, A.R.; Angelini, R.; Christensen, V. More than Anecdotes: Fishers’ Ecological Knowledge Can Fill Gaps for Ecosystem Modeling. PLoS ONE 2016, 11, e0155655. [Google Scholar] [CrossRef]
  62. Steins, N.A.; Baker, M.R.; Brooks, K.; Mackinson, S.; Stephenson, R.L. Editorial: Co-Creating Knowledge with Fishers: Challenges and Lessons for Integrating Fishers’ Knowledge Contributions into Marine Science in Well-Developed Scientific Advisory Systems. Front. Mar. Sci. 2023, 10, 1338271. [Google Scholar] [CrossRef]
  63. Department of Fisheries and Marine Research. Cyprus Annual Report on Efforts During 2023 to Achieve A Sustainable Balance Between Fishing Capacity and Fishing Opportunities; Department of Fisheries and Marine Research: Nicosia, Cyprus, 2024; p. 31.
  64. Prellezo, R.; Sabatella, E.; Virtanen, J.; Guillen Garcia, J. Scientific, Technical and Economic Committee for Fisheries (STECF)—The 2022 Annual Economic Report on the EU Fishing Fleet (STECF 22-06); European Union: Luxembourg, 2022. [Google Scholar]
  65. Zappes, C.A.; Simões-Lopes, P.C.; Andriolo, A.; Di Beneditto, A.P.M. Traditional Knowledge Identifies Causes of Bycatch on Bottlenose Dolphins (Tursiops truncatus Montagu 1821): An Ethnobiological Approach. Ocean Coast. Manag. 2016, 120, 160–169. [Google Scholar] [CrossRef]
  66. Braga, H.D.O.; Schiavetti, A. Attitudes and Local Ecological Knowledge of Experts Fishermen in Relation to Conservation and Bycatch of Sea Turtles (Reptilia: Testudines), Southern Bahia, Brazil. J. Ethnobiol. Ethnomed. 2013, 9, 15. [Google Scholar] [CrossRef]
  67. Otero, M.; Serena, F.; Gerovasileiou, V.; Barone, M.; Bo, M.; Arcos, J.M.; Vulcano, A.; Xavier, J. Identification Guide of Vulnerable Species Incidentally Caught in Mediterranean Fisheries; IUCN: Malaga, Spain, 2019; p. 204. [Google Scholar]
  68. Di Natale, A.; Mangano, A.; Maurizi, A.; Montaldo, L.; Navarra, E.; Pinca, S.; Schimmenti, G.; Torchia, G.; Valastro, M. A Review of Driftnet Catches by the Italian Fleet: Species Composition, Observers’ Data and Distribution along the Net. ICCAT Col. Vol. Sci. Pap. 1994, 44, 226–235. [Google Scholar]
  69. Silvani, L.; Gazo, M.; Aguilar, A. Spanish Driftnet Fishing and Incidental Catches in the Western Mediterranean. Biol. Conserv. 1999, 90, 79–85. [Google Scholar] [CrossRef]
  70. Di Natale, A. Driftnets Impact on Protected Species: Observer Data from the Italian Fleet and Proposal for a Model to Assess the Number of Cetaceans in the by-Catch. ICCAT Coll. Vol. Sci. Pap. 1995, 44, 255–263. [Google Scholar]
  71. Garagouni, M.; Avgerinou, G.; Mouchlianitis, F.-A.; Minos, G.; Ganias, K. Questionnaire and Experimental Surveys Show That Dolphins Cause Substantial Losses to a Gillnet Fishery in the Eastern Mediterranean Sea. ICES J. Mar. Sci. 2022, 79, 2552–2561. [Google Scholar] [CrossRef]
  72. Boisseau, O.; Frantzis, A.; Petrou, A.; van Geel, N.; McLanaghan, R.; Alexiadou, P.; Moscrop, A. Visual and Passive Acoustic Survey Report; AP Marine Environmental Consultancy: Nicosia, Cyprus, 2017; p. 49. [Google Scholar]
  73. Kerem, D.; Frantzis, A.; Scheinin, A.; Goffman, O. Steno Bredanensis (Mediterranean Subpopulation); IUCN: Gland, Switzerland, 2021. [Google Scholar]
  74. Çanakcı, T.; Özden, Ö.; Fuller, W.; Erkol, I.L.; Tonay, A.M. Plastic Lure Ingestion by Rough-Toothed Dolphin Steno Bredanensis Stranded on the Northern Coast of Cyprus. J. Black Sea/Mediterr. Environ. 2023, 29, 127. [Google Scholar]
  75. DeMaster, D.P.; Fowler, C.W.; Perry, S.L.; Richlen, M.F. Predation and Competition: The Impact of Fisheries on Marine-Mammal Populations Over the next One Hundred Years. J. Mammal. 2001, 82, 641–651. [Google Scholar] [CrossRef]
  76. Plagányi, É.E.; Butterworth, D.S. Competition with Fisheries. In Encyclopedia of Marine Mammals; Elsevier: Amsterdam, The Netherlands, 2009; pp. 269–275. ISBN 978-0-12-373553-9. [Google Scholar]
  77. Oxtoby, L.E.; Horstmann, L.; Budge, S.M.; O’Brien, D.M.; Wang, S.W.; Schollmeier, T.; Wooller, M.J. Resource Partitioning between Pacific Walruses and Bearded Seals in the Alaska Arctic and Sub-Arctic. Oecologia 2017, 184, 385–398. [Google Scholar] [CrossRef]
  78. Feliu-Tena, B.; Rodilla, M.; Pastor, J.; Abalo-Morla, S.; Bou-Cabo, M.; Belda, E.J. Evaluating Dolphin Damage in Trammel Net Fisheries in the Valencia Region: Insights to Improve Management. Reg. Stud. Mar. Sci. 2023, 65, 103075. [Google Scholar] [CrossRef]
  79. Dawson, M.S.; Northridge, S.; Waples, D.; Read, J.A. To Ping or Not to Ping: The Use of Active Acoustic Devices in Mitigating Interactions between Small Cetaceans and Gillnet Fisheries. Endanger. Species Res. 2013, 19, 201–221. [Google Scholar] [CrossRef]
  80. Tixier, P.; Gasco, N.; Duhamel, G.; Guinet, C. Habituation to an Acoustic Harassment Device (AHD) by Killer Whales Depredating Demersal Longlines. ICES J. Mar. Sci. 2015, 72, 1673–1681. [Google Scholar] [CrossRef]
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Figure 1. Number of interviews conducted with small-scale and large pelagic fishers across the different regions in the Republic of Cyprus.
Figure 1. Number of interviews conducted with small-scale and large pelagic fishers across the different regions in the Republic of Cyprus.
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Figure 2. Percentage (%) contribution of each identifying characteristic of dolphin depredation by fishers. SSF: Small-scale fishery, LPF: Large pelagic fishery.
Figure 2. Percentage (%) contribution of each identifying characteristic of dolphin depredation by fishers. SSF: Small-scale fishery, LPF: Large pelagic fishery.
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Figure 3. Examples of damages caused to fishing gear and catch after a depredation event by dolphins. (A,B) examples of damages caused on monofilament gillnets of about 80–120 cm in diameter and (C) damage caused on trammel nets of about 30 cm in diameter. (D) is an example of damage caused on the catch (albacore tuna fishery) after a depredation event. Depredation on about 60 individuals.
Figure 3. Examples of damages caused to fishing gear and catch after a depredation event by dolphins. (A,B) examples of damages caused on monofilament gillnets of about 80–120 cm in diameter and (C) damage caused on trammel nets of about 30 cm in diameter. (D) is an example of damage caused on the catch (albacore tuna fishery) after a depredation event. Depredation on about 60 individuals.
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Figure 4. Interaction probability between dolphins and fishing operations throughout the different months of the year for the two different fleet segments. Probability scale: 0 = no interaction, 1 = high interaction probability. SSF: Small-scale fishery, LPF: Large pelagic fishery.
Figure 4. Interaction probability between dolphins and fishing operations throughout the different months of the year for the two different fleet segments. Probability scale: 0 = no interaction, 1 = high interaction probability. SSF: Small-scale fishery, LPF: Large pelagic fishery.
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Figure 5. (A) Dolphin–fisheries interaction rate and (B) dolphin bycatch rate per year per fleet segment. 0 = no interaction, 1 = maximum interaction rate. Bycatch rate calculated as the number of individuals bycaught per year. The upper and lower ranges represent the minimum and maximum values. SSF: Small-scale fishery, LPF: Large pelagic fishery.
Figure 5. (A) Dolphin–fisheries interaction rate and (B) dolphin bycatch rate per year per fleet segment. 0 = no interaction, 1 = maximum interaction rate. Bycatch rate calculated as the number of individuals bycaught per year. The upper and lower ranges represent the minimum and maximum values. SSF: Small-scale fishery, LPF: Large pelagic fishery.
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Figure 6. Economic loss on (A) catch and (B) fishing gear per year. The upper and lower whiskers represent the minimum and maximum values. SSF: Small-scale fishery, LPF: Large pelagic fishery.
Figure 6. Economic loss on (A) catch and (B) fishing gear per year. The upper and lower whiskers represent the minimum and maximum values. SSF: Small-scale fishery, LPF: Large pelagic fishery.
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Figure 7. Alluvial plot illustrating the combination of responses to the following questions: “What is your experience with the use of dolphin acoustic deterrent devices?”; “What is your opinion?”; and “What is the reason for your opinion?”. The thickness of each flow represents the percentage of responses (%) for each respective question. Numbers indicate the number of responses per answer.
Figure 7. Alluvial plot illustrating the combination of responses to the following questions: “What is your experience with the use of dolphin acoustic deterrent devices?”; “What is your opinion?”; and “What is the reason for your opinion?”. The thickness of each flow represents the percentage of responses (%) for each respective question. Numbers indicate the number of responses per answer.
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Table 1. Percentage contribution of the type of interaction reported by fishers grouped by taxa. SSF: Small-scale fishery, LPF: Large pelagic fishery. No. of SSF = 55, No. of LPF = 9.
Table 1. Percentage contribution of the type of interaction reported by fishers grouped by taxa. SSF: Small-scale fishery, LPF: Large pelagic fishery. No. of SSF = 55, No. of LPF = 9.
Damage on CatchDamage on Fishing GearCatch ScatteringNo Interaction
SpeciesSSF (%)LPF (%)SSF (%)LPF (%)SSF (%)LPF (%)SSF (%)LPF (%)
Dolphins98.288.998.255.696.488.90.00.0
Turtles94.555.696.455.621.80.00.00.0
Monk seal94.50.090.90.043.60.00.0
Puffer fish92.70.094.50.01.80.00.00.0
Elasmobranchs1.822.21.822.232.70.00.00.0
Table 2. List of fish species and categories that dolphins prefer to depredate on, based on fishers’ responses, along with the corresponding response frequencies. SSF: Small-scale fishery, LPF: large pelagic fishery. No. of SSF = 55, No. of LPF = 9.
Table 2. List of fish species and categories that dolphins prefer to depredate on, based on fishers’ responses, along with the corresponding response frequencies. SSF: Small-scale fishery, LPF: large pelagic fishery. No. of SSF = 55, No. of LPF = 9.
Species/Fish CategoriesSSF (%)LPF (%)
Boobs boobs100.00.0
Spicaras smaris100.00.0
Spicara maena100.00.0
Small pelagic41.80.0
Scomber japonicus36.40.0
Trachurus spp.30.90.0
Mullus barbatus29.10.0
Mullus surmuletus29.10.0
Pagellus acarne29.10.0
Auxis rochei21.80.0
Dentex dentex9.10.0
Etrumeus teres7.30.0
Sardina pilchardus5.50.0
Seriola dumerili5.50.0
Pagrus pagrus3.60.0
Sparisoma cretense3.60.0
Diplodus sargus3.60.0
Parupeneus forsskali1.80.0
Shiny/white fish1.80.0
Diplodus vulgaris1.80.0
Thunnus alalunga0.0100.0
Xiphias gladius0.022.2
Coryphaena hippurus0.022.2
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MDPI and ACS Style

Papageorgiou, M.; Hadjieftychiou, S.-I.; Christodoulou, C.; Petrou, A.; Moutopoulos, D.K. Describing Dolphin Interactions with Cypriot Fisheries Using Fishers’ Knowledge. J. Mar. Sci. Eng. 2024, 12, 2240. https://doi.org/10.3390/jmse12122240

AMA Style

Papageorgiou M, Hadjieftychiou S-I, Christodoulou C, Petrou A, Moutopoulos DK. Describing Dolphin Interactions with Cypriot Fisheries Using Fishers’ Knowledge. Journal of Marine Science and Engineering. 2024; 12(12):2240. https://doi.org/10.3390/jmse12122240

Chicago/Turabian Style

Papageorgiou, Marios, Soteria-Irene Hadjieftychiou, Chistodoulos Christodoulou, Antonis Petrou, and Dimitrios K. Moutopoulos. 2024. "Describing Dolphin Interactions with Cypriot Fisheries Using Fishers’ Knowledge" Journal of Marine Science and Engineering 12, no. 12: 2240. https://doi.org/10.3390/jmse12122240

APA Style

Papageorgiou, M., Hadjieftychiou, S.-I., Christodoulou, C., Petrou, A., & Moutopoulos, D. K. (2024). Describing Dolphin Interactions with Cypriot Fisheries Using Fishers’ Knowledge. Journal of Marine Science and Engineering, 12(12), 2240. https://doi.org/10.3390/jmse12122240

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