The conflict between fisheries and cetaceans in Bulgaria’s Black Sea territorial waters
Zornitsa Zaharieva (1), Venislava Racheva (2), Dimitar Parvanov (3), Ventseslav Delov (1)
1.Department of Zoology and Anthropology, Faculty of Biology, Sofia University “St. Kliment
Ohridski”, Sofia, Bulgaria
E-mail: zornitsa_zaharieva@yahoo.com
2. Department of Ecology and Environmental Protection, Faculty of Biology, Sofia University
“St. Kliment Ohridski”, Sofia, Bulgaria
3. Research Department, Nadezhda Women’s Health Hospital, 3 “Blaga vest” Street, Sofia,
Bulgaria
Abstract
Conflicts between fisheries and cetaceans remain in many areas around the world, and the
Bulgarian territorial waters of the Black Sea is not an exception. The types and extent of such
conflicts have been incidentally studied, and a relevant policy of conflict management currently
does not exist. To start filling the gap, a field study during the period between 2012 and 2014
interviewed fishers working on about 50 per cent of the existing dalyans (the traditional
Bulgarian fishing gear). The research objective was to identify the current fishers' attitudes and
knowledge about cetaceans, the damage caused by the local marine mammals to their gear, their
proposals for resolving the problems, and what they did in their practice. A specially designed
questionnaire provided a snapshot of the prevailing situation. The answers analysis confirm
conclusions made by various early studies in other areas (Reeves et al., 2001; Bearzi, 2002) that
the conflict between fishers and cetaceans is caused mainly by insufficient knowledge about the
cetaceans, accumulated negative attitudes regarding the impact of dolphins on the fisheries, as
well as insufficient access to modern fisheries equipment and practices. Successful management
and sustainable resolution of this conflict are essential also due to its growing impact on the
Bulgarian fishing industry effectiveness and protection of the Black Sea biodiversity. The study
recommends measures for comprehension the fishers knowledge about cetaceans behaviour and
their real role regarding the amount of fish available to fisheries. Further development of the
Bulgarian fisheries policy may create real financial opportunities for the fishers to acquire
repellent gears and apply modern ecologically-safe fishing practices. Scientific organisations,
national and local institutions, and fishing associations are invited to co-operate for systematic
monitoring and studies of the fishers-dolphin interactions to secure the sustainable use of fishery
resources as well as the maritime ecology system.
Keywords: Marine mammals Cetaceans, fishing, fisheries, Black sea, Bulgaria
Introduction
Interactions of cetaceans with fisheries have recently turned into a two-dimensional problem ecological and economic. The ecological dimension reflects the impact of incidental catching of
cetaceans in fishing operations, fractures or fatality from revenging actions taken by fishers to
secure the fishing value, habitat degradation, and forced changes of behaviour or migration
(Read, 1996; Northridge & Hoffman, 1999; Bearzi G., 2002).
The economic dimension considers fishing business productivity and value. The
cetaceans may cause meaningful time, money, and gear loos to fisheries reducing the catch rate
by depredation, breaking the set-nets, and reducing the size or quality of the catch (Northridge &
Hoffman, 1999; Reeves et al., 2001; Bearzi G., 2002; Lauriano et al., 2004). Although the
interaction with dolphins and other cetaceans may also have sizable economic benefits (Bearzi
G., 2002), the fishers generally have a negative attitude and sometimes undertake actions against
the cetaceans. Occasionally, such adverse reactions may include attempts to scare animals away
by employing dangerous methods such as dynamite (Reeves et al., 2001; de Stefanis, 2004).
Alternatively, fishers may lobby cetacean culls (Lauriano et al., 2004).
In the Bulgarian Black Sea zone, a tendency comparable to those observed worldwide has
also been identified and documented. The importance of the dolphin-fishers conflict is growing
due to the tourism-driven rising of demands and prices in the last two decades. The Black Sea is
a closed, intercontinental sea. It connects to the Mediterranean, and thus to the rest of the world’s
oceans, only through the Bosphorus Strait (Prodanov et al., 1997). Three species representative
of odontocetes (dolphins and porpoise) occur in the Black Sea – Black Sea Harbour Porpoise
(Phocoena phocoena ssp. relicta), Black Sea Common Dolphin (Delphinus delphis ssp.
ponticus) and Black Sea Bottlenose Dolphin (Tursiops truncatus ssp. ponticus). Due to the
isolations of the Black Sea, they are defined as separate subspecies that occur only here (Tzalkin,
1938; Barabasch – Nikiforov, 1960; Amaha, 1994; Rosel at al.,1994).
The hunting of odontocetes that occurred in the middle of the 20th century caused a sharp
decline in the populations of the three species in the Black Sea. As the largest predators here, the
marine mammals are vulnerable to various factors such as water pollution, food shortages,
microbial contamination, habitat loss, and incidental catches (Birkun, 2002). Even though
odontocetes' conservation, including their interaction with fisheries, is seen as a significant
challenge worldwide, especially in isolated water basins as the Black Sea, systematic studies of
the drivers, conditions, and effects on both sides are very limited in the Black Sea basin, and
generally lacking in Bulgaria. However, during the last 15 years, due to a growing role of the
"green" civil organisation and environmental issues, the conflict between dolphins and fishers
was better illuminated and broadly debated in society and the media.. The public news reflects
the strong discontent among fishers due to claims that dolphins and porpoises cause significant
damages to their fishing gear and the catch rate. However, the societal discourse and possible
legal arrangements and policy of mitigation need a precise definition of the conflict' scope,
factors, conditions, and consequences. This study specifically focuses on the known or perceived
impact of the interactions between odontocetes and fishers, who use the favourite type of gear
along the Bulgarian Black Sea coast, - the dalyan.
Methods
Study area
Bulgaria is a European country located in the southeastern parts of the continent, occupying the
central and eastern boundaries of the Balkan Peninsula to the south of the Danube River, with a
full outlet of the Black Sea to the east. The Black Sea coastline of 378 km defines Bulgaria too as
a maritime and fisheries country. The coastline is divided north and south by geographic and
economic specifics, which also reflect the seasonal distribution of fish species and the territorial
deployment of fishing gear dalyan. Consequently, the study area follows the north-south divide.
The fieldwork and fact-finding visits included the following fish landing sites (Figure 1).
Figure 1. Study area: the Bulgarian Black Sea coast. Study sites: on North Bulgaria - Biala,
Varna, Albena, Kranevo, Balchik, Kavarna, Kaliakra, and St. Nikola; on South Bulgaria Pomorie, Primorsko, Tsarevo, Ahtopol, and Sinemorec.
Description of the fishing gear dalyan
A law defines the dalyan as a “special gear” and its deployment and use are under government
control. Dalyan is a stationary pound net used for passive commercial fishing. It has a point of
attachment to the seabed and on the beach (Fisheries and Aquaculture Act, 2005; Art. 21). To
service the dalyans, the fishermen use a small boat, usually around 12m long and motorized. The
main fish species caught with this gear, are pelagic such as sprat (Sprattus sprattus), horse
mackerel, (Trachurus mediterraneus), garfish (Belone belone), and pontic shad (Alosa
immaculata). This type fishing gear is employed particularly in Bulgaria, Greece, and Turkey
(Figure 2).
Data collection
The primary data collection method was "face-to-face" (in person) interviews with the
fishers using a specially formulated questioner (see Appendix 1) and additional clarifying
questions, if needed (Rea & Parker, 1997). Examining the attitude and problems of the fishers
can help resolve the conflict by better understanding attitudes, beliefs, expectations, levels of
support or opposition, as well as the factors influencing them. This method of data collection has
already been used for different species of odontocetes (spinner dolphins, humpback dolphins,
bottlenose dolphins, and others) for examining issues as the size of bycatch and populations
(Omar et al., 2002; Kuznetsov, 2004).
Data were collected from May 2012 to September 2014, using a specially designed
questionnaire (see Appendix 1). Interviews were conducted on the fish landing sites and some of
the dalyans were visited immediately after incidents had occurred in order to see the amount and
type of damages potentially caused by odontocetes. Fishermen answered questions concerning
the vessels they use and the fish species they target, their attitudes toward and knowledge about
cetaceans, the amount of damage sustained to their gear, their proposals resolving the problems
and what they actually did in their practice. General personal information was also collected age, education, experience as a fisherman.
The questionnaire
The fishers were asked to answer questions concerning the used vessels and the fish species they
catch; their attitudes toward and knowledge about cetaceans; the significance and cost of damage
to the gear; general personal information as age, education, and occupational experience.
Particular attention was paid to their proposals for resolving the problems and what they
practically did. The questionnaire consisted of 23 questions divided into four sections,
corresponding to a various aspect of the conflict and the research aims:
1. Five questions enquired the general respondents' knowledge about cetaceans.
2. Eleven questions aimed to elaborate on the fishers' personal experience with cetaceans.
3. The behaviour of cetaceans during an attack was discussed in two questions.
4. Some respondents’ personal information was collected in five questions.
Eighteen of the questions contained multiple-choice options, and in five of them the
answer "do not know" was possible to minimise attempts to guess. In 10 of the questions, the
answer "other" was an option to allow sharing respondents' personal opinion and ideas.
Method of data analysis
A Chi-square test with contingency tables was performed to compare the answers from
the questionnaire between the interviewed fishermen from the southern and northern Black Sea
coast. A Student’s t-test was carried out to assess differences in fishermen’s age between the
studied regions. A multiple comparison procedure, Fisher's Least Significant Difference (LSD),
was used to determine divergences among (1) fishers with a particular attitude to dolphins and
proposed measures to mitigate the conflict, (2) the answers given by fishers to particular
questions and their age. Statistical data analysis was performed using SPSS v.21. А P value of
less than 0.05 was considered statistically significant.
Results
The central part of the survey aimed to capture the fishers' personal experience with cetaceans whether there have been interactions between fisheries and marine mammals, what types of
interaction occurred, and what measures fishermen recommended to mitigate the conflicts.
Sixty-one fishers, working on 54 separate dalyans (roughly 50 per cent of dalyans in the
Bulgarian Black Sea waters) responded to the questioner and additional questions (Table 1). As
the local fishing industry is still predominantly a male occupation, only men (n = 61) participated
in the surveys.
Table 1. The number of interviewed fishermen by location.
Study area
Region
Number of interviewed
Percent of the sample
Albena
North
2
3,28%
Ahtopol
South
5
8,20%
Balchik
North
8
13,11%
Varna
North
3
4,92%
Kavarna
North
8
13,11%
Kaliakra
North
3
4,92%
Kranevo
North
3
4,92%
Obzor - Byala
North
3
4,92%
Pomorie
South
8
13,11%
Primorsko
South
7
11,48%
Sveti Nikola
North
2
3,28%
Sinemorec
South
4
6,56%
Tsarevo
South
5
8,20%
61
100 %
Total
The questionnaire also included the trends in odontocetes distribution as observed by the
fishermen. On this subject, 100% of respondents indicated an opinion that the number of
dolphins and porpoises in the Black Sea is rapidly increasing. In general, all interviewed
fishermen believe that the animal counts are in the millions (the most significant number
mentioned was about 10 million individuals).
Damage
When asked about the type of damages caused by cetaceans, 74 per cent of the
interviewed indicated "all listed", a category which included the following: а-destruction and
damage to fishing gear, b-consumption of fish, c-scaring the fish; d-all listed, e-other. There were
significantly less instances of respondents giving a more specific answer: a-13,11%; a, b-11,48
%; a, c-1,64 %). With regard to seasonality of damage caused by odontocetes, in the northern
area, there were significantly more serious incidents in summer and winter, whereas in the
southern region, these incidents occurred mostly in spring and autumn (χ2 = 9.726, p = 0.045)
(Figure 3). As an additional comment, 100 per cent of the fishermen noted that the fish stocks
had fallen sharply over the last ten years, and in their opinion perhaps this is one of the reasons
why marine mammals attack the gear and cause serious damages and catch loss. In three cases,
the fishermen declared that they had to give up this way of fishing through the dalyan, because of
the large daily damage and catch loss caused by the cetaceans - ( Z. A. Zaharieva, pers. comm.,
15 May 2014).
Figure 3. A seasonal variation of damages in the southern and northern Bulgarian Black Sea
regions. 1 – Registered damages during spring, 2 – Registered damages during spring, summer,
and autumn, 3 – Registered damages during all seasons, 4 – Registered damages during spring
and autumn, 5 – Registered damages during spring and summer.
Education and knowledge
The data collected about the fishermen education status and knowledge of cetaceans,
namely how many species inhabit the Black Sea, what their main characteristics are, and what
their conservation status is, helps to understand what arguments and motives drive their attitudes
regarding the conflict (see Appendix). Most of the questioned fishermen - 78.26 per cent have
secondary education, without significant differences between the two regions (P> 0.05).
However, regarding the concrete knowledge about the species in the Black Sea, in the northern
region 78.1 per cent responded correctly, while in the southern region only 55.2% did (χ2 =
3.637, p = 0.05) (Figure 4)
.
Figure 4. The fishermen’ answers to the question “How many species of cetaceans do you know
in the Black Sea?”.
Regarding the impact of the age on fishermen knowledge and understanding of the
cetaceans, the respondents who answered "1 species" tended to be younger than respondents who
answered "2" and "3" species (Figure 5). However, 100 per cent of the interviewed answered
correctly that any encroachment on the cetaceans is forbidden. Indeed, in Bulgaria, cetaceans are
included in the Biodiversity Act (Appendix II and Appendix III), which says "... all forms of
deliberate capture or killing of specimens are completely forbidden by any means and methods,
persecution and disturbance".
Figure 5. Correlation between age of respondents and their answers to the question “How many
species of cetaceans do you know in the Black Sea?”
Attitude
The majority of respondents (44.26 per cent) demonstrated a positive attitude regarding
the cetaceans based on their knowledge and occupational experience while less than 20 per cent
took a negative stance. The significant percentage of those declared a neutral perspective (36.07
per cent) completed a generally positive picture of the Bulgarian fishermen attitude toward
cetaceans (Figure 6)
Figure 6. Percentage ratio of fishermen's attitude to cetaceans
There were significant differences in the attitude of fishermen from the two regions to
cetaceans. Fishermen from the northern region had a much more positive attitude than the
fishermen from the south, where extremely negative attitudes were observed (χ2= 12.252, p =
0.016).
45,0%
40,0%
35,0%
30,0%
25,0%
20,0%
15,0%
10,0%
5,0%
0,0%
North
South
Figure 7. Percentage ratio in the two regions.
Unintentional catch
Regarding the impact of dalyans on cetaceans, the fishermen shared that they rarely find
entangled cetaceans in dalyans. However, there have been five instances of cetacean mortality
reported over the last three years: one dead bottlenose dolphin in Kavarna, another one in
Sinemorets, and three harbour porpoises in Ahtopol.
Tackling the problems
According to the interviewed, in most of the cases (53 per cent) of entangled in dalyans
cetaceans actions have not been required as the marine mammals have left the dalyans on their
own creating large holes torn in the nets. In 27.43 per cent of the cases, when the cetaceans have
been still inside the gear, the fishers have opened the nets and let the animals out.
The fishermen were also asked what measures they would recommend as most effective in
dealing with cetaceans, with the following options: a) culling, b) scaring agents, c) other, please
describe, d) I do not consider any measures necessary. (Figure 8). The question was provoked by
the research team’s interest in learning how many fishermen were aware of contemporary
prevention methods. As part of the analysis, the research team did not identify any significant
differences between the two regions pertaining to how fishermen deal with cetaceans entering
their gear (χ2 = 3.020, p = 0.389). However, there were significant differences between
responses to the question of which method was most effective in reducing cetacean numbers: in
the southern region, considerably more fishermen considered culling to be a suitable method (x2
= 26.028, p <0.001). This was corroborated by the more negative attitude fishermen held toward
cetaceans in the south.
Figure 8. Distribution of measures proposed by fishermen against the cetaceans. 1 – by culling
cetaceans, 2 – by using acoustic deterrent devices to scare cetaceans, 3 –other measures, 4 – do
not consider any measures necessary.
Discussion
In this report, the research team presents some results of the investigation of the interactions
between Bulgarian fishers using a traditional gear dalyan, and the local cetaceans - bottlenose
dolphin, short-beaked common dolphin, and harbour porpoises. The study is the first ever
attempt to assess the conflict between fisheries and cetaceans in the Bulgarian Black Sea
territorial waters. Despite the existence of information that in some areas the fishers suffer from
either dalyan damage and reduced catch, or time and money loss, no effort has been made yet to
frame the problem, evaluate practices, and propose normative and technical solutions. As an
initial effort, the study did not aim to fill all knowledge and management gaps. Instead, the
objective was to start building a quantitative ground for the systematic study of the fisherscetaceans conflict' basic dimensions: the fisheries economics and ecosystem sustainability.
From the research perspective, the methods of collecting and analysing information
provided opportunities for closer contact with the fishers. As in most cases small co-operatives
exploit the dalyans, the fishers personal experience, attitudes, and expectations of the problemsolving were in the study focus.
The study approach and method of work were well-accepted by the respondents. The
interviewed fishers provided valuable information and shared their opinions on demanded
measures openly. Тhe reason for their co-operative attitude is probably the understanding that
fishers are unable to solve the problem of cetaceans themselves and in their desire to gain a
broader public, political (in terms of proper normative regulations), and technical support. While
analysing the data, special attention was paid, first, not only to build a complex picture but also
to underline the specifics of the two coastline regions. Secondly, to identify the impact of the
fishers' age on their attitudes toward the cetaceans. Both observations are intended to provide a
ground for establishing a consolidated approach to conflict mitigation through systematic
monitoring, research, and awareness raising.
The results reveal a considerable conflict because of damages caused by cetaceans to
fishermen's traditional fishing gear and the subsequent loss of catch, time and money. Most
fishers demonstrated severe concerns about their livelihood because of the inability to
compensate for the damages caused by the cetaceans. In their view, with increased demand for
fish as a result of the tourist boom in the last decade, any serious catch loss may lead to a
cessation of business.
The generally negative attitude toward marine mammals is feeded also by the
fishers' impression that the number of cetaceans in the Bulgarian territorial waters is rising
rapidly. The fishers see the extended cetaceans population as the primary reason for the attacks
on delyans. Such high counts about the size of odontocetes population probably result from the
frequent interactions between fishers and marine mammals. However, according to the latest
census as of 2014-2015, the number of marine mammals is estimated as 1,057 (613-1500) for
Tursiops truncatus, 4886 (128-9643) for Phocoena phocoena, and 8207 (2752 - 13662) for
Delphinus delphis (Black Sea Research Program NOAH [BSRPN], 2015).
The research also investigated the seasonal rate of interactions and dalyan sets damages.
The analysis illustrates the link between the incidents in dalyans and the migration of fish across
the region - the more active fishing is accompanied by more damage. In the northern area, higher
severe incidents have been registered in the summer and autumn while in the south, these occur
more frequently in the spring and autumn. Such dispersion is because, in the Black Sea, the fish
migrates from the south to the north and reaches the northern latitudes a few weeks later
(Stoyanov et al., 1963). In both areas, during the winter months, the dalyans are not placed in the
water and did not suffer from the marine mammals' attacks and incidents. However, in the
northern area, the fishers use other then dalyan types fishing gear during the winter months. They
informed the study that even with other types of gear, they ran into problems with cetaceans
harming the gear, albeit at a lesser frequency.
Concerning the fisher's knowledge about cetaceans, the results of the study indicated a
general lack of awareness, especially among the younger generation. Knowledge about the
different species of cetaceans is essential because they behave differently and have different
seasonal dynamics and their effective differentiation may help fishers to find better ways to
tackle the problem. Some respondents voiced dissatisfaction with the strictly protected status of
the cetaceans, saying that the catch quotas for cetaceans that were in place at the beginning of the
last century should be brought back.
Regarding the damage caused by the use of dalyans, the study considered that the number
of dead bottlenose dolphins in the examined dalyans (total two) for the last three years is too
small to have a negative impact on the species. The same goes for the dead harbour porpoises only three individuals for three years. Specific low numbers suggest that dalyan nets are not a
serious obstacle or a threat to cetaceans, although they may cause mortality in some cases. The
construction of the dalyan itself, as well as the type of used net, are not a serious obstacle for
cetaceans, as they are free to enter the gear and often it leaves undisturbed.
During the survey, the research team acquired information on fishers' practical measures
to prevent cetaceans from entering the dalyans. Many fishers place additional nets around their
gear, which subsequently prove not to be particularly useful because the animals go through
them easily. Another method in use is to place a scarecrow on a boat placed next to the gear.
Some fishers admitted to using dynamite to hold the animals away, which could be a criminal
act. Often fishers used to guarding the dalyans at night in person shining spotlights from boats.
The fishers recommendations for more effective dealing with cetaceans provided light on
the possibilities for addressing the conflict in the long-term perspective, achieving a balance
between the fisheries and marine mammals in the Black Sea. The research team sees reality as
complicated and controversial. Due to insufficient knowledge about the species and poor
awareness about the modern methods for dealing with fishing problems with marine mammals,
the fishers preventive measures proposals were mostly improvised and inconsistent with the
behaviour and biology of cetaceans, which renders them ineffective. According to fishers, the
most effective action to limit the damage caused by marine mammals is by reducing their
numbers through culling.
In conclusion, the study recognised and framed a substantial on-going conflict between
the fishers using dalyan gears and local cetaceans in the Bulgarian Black Sea territorial waters.
Frequent damages from cetaceans on the dalyan fishing gear lead to economic losses. Combined
with the ineffective measures that fishers apply against them, these attacks are the root causes of
the conflict. From the fishers' perspective, it has profound consequences for their livelihoods,
both directly and indirectly, as they suffer from raiding and destruction of fishery catch; damage
and decrease to fishery catches; loss of income from sales and repairment of nets; damage of
property (fishnets and other equipment). The economic damage drives the raising negative
attitudes toward cetaceans. In terms of the local marine mammals' protection and sustainability,
the study identified rare cases of tangled and dead cetaceans in dalyans.
Recommendations
As an initial effort in the fisheries-maritime mammals problematic in Bulgaria, this study has
limits in terms of methods of work and scope of research. Introducing technical methods for
verification of the interactions between cetaceans and fishing gear dalyan would provide more
reliable data for the character of threats to both cetaceans and pound nets. The scope of the
research was limited to the fishers' opinion and attitudes while other economic and ecological
factors were not addressed recently.
However, the study provides a convincing basis for some recommendations. It is of
utmost importance to improve the fishers' knowledge about the local cetaceans. The expected
outcome would be an improved fishing gear construction and use in terms of both protecting the
catch and saving the lives of cetaceans. An accompanying effort may provide better awareness of
the modern methods for conflict mitigation, ones consistent with the biology and ecology of the
marine mammals. A practical and sustainable resolution of the conflict would require research on
the potential impact of repellent devices as a way to mitigate the conflict. Creating financial
opportunities for fishers to acquire repellent gears (such as pingers) can lead to a change in their
attitude towards cetaceans and improve the economic situation of the fisheries in Bulgaria.
Finally, establishing contacts and working relationships between scientific organisations,
national and local institutions, and fishing associations would be a useful basis for effect oriented
management of the local fishery resources and protection of the Black Sea biodiversity.
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