1. Introduction
Aquaculture, or farming fish and other aquatic organisms, is an important and rapidly growing food-production industry around the world [
1]. The EU’s Blue Growth Strategy identifies aquaculture as a sector with a high potential which could boost economic growth across the continent and bring social benefits through new jobs [
2,
3].
Modern aquaculture should be developed as a system to increase product quantity and quality while preserving the environment, considering economic robustness, development of high-quality jobs and building of new relationships among producers, consumers, and the production systems and their associated products [
4]. There are two main sections of inland aquaculture in Europe: extensive traditional carp farming in earth ponds and intensive trout farming in different productive facilities. In the case of intensive trout farming, as in the case of majority of intensive forms of aquaculture in the world, the ecosystem approach consists primarily in minimizing the adverse impact on the environment [
5,
6]. The situation is different in the case of traditional carp pond farming, which has been developing in Central European countries for centuries [
7,
8,
9].
Traditional carp production is based on the use of natural food with supplementary feeding with cereals. The contribution of supplementary feed to the carp growth gain amounts to around 25–50% of the total yield [
10]. This semi-extensive fish production averages around 450–500 kg of fish per ha [
11]. Owing to the open nature of the ponds, their integration with the local water body system and the natural feed-based management, such ponds have become integral parts of the local environment. Ponds play important landscape-related functions, especially in areas with no natural surface waters. Apart from fish production, they supply many services, such as protection against floods, increasing water retention, creating a microclimate and increasing biodiversity [
12,
13,
14]. A considerable number of ponds are situated in Nature 2000 sites [
15,
16,
17] and in those classified as nature reserves and protected landscape areas [
9,
13,
14], whose specific features developed under the influence of active fishponds. All these benefits enable the ponds to be defined as an aqua-ecosystem, i.e., a human-managed aquatic ecosystem oriented towards the provision of ecosystem services [
4].
The origins of the ecosystem services are to be found in the late 1970s, as a joint initiative of economists and ecologists [
18]. They stressed that the valuation of nature services in economic decisions could correct an incorrect assessment of the relationship between man and nature. The most universal definition of ecosystem services was proposed by Costanza et al. [
19] as: “the benefits that mankind gains directly or indirectly from the ecosystem functions”. Much more complex systems of the service classification have been developed since then, including the UN Millennium Ecosystem Assessment [
20] and the Common International Classification of Ecosystem Services—CICES [
21].
Fishponds provide ecosystem services similar to those generated by natural wetlands and shallow lakes [
14,
22,
23]. However, unlike natural water bodies, water and trophic conditions in the ponds are controlled and modified by fish farmers. Therefore, the above-mentioned services more closely match the definition of non-commodity outputs in the concept of multifunctional aquaculture [
24,
25] than services using the concept of ecosystem services regarding natural ecosystems [
20].
Agriculture as well as aquaculture is considered multifunctional when it can produce various non-commodity outputs or has other additional functions for food production [
26]. Multifunctional agriculture and ecosystem services emerged during the same period and both were recognized as two important concepts for sustainable agricultural development and agricultural policymaking. The two concepts are closely related through their use of the term “function”. However, multifunctional agriculture considers functions as agricultural activity outputs and prefers farm-oriented approaches, whereas ecosystem services consider ecosystem functions in the provision of services and prefer service-oriented approaches [
27]. In other words, in multifunctional fish farming, all the commodity and non-commodity functions of the fishpond are the result of deliberate management. According to Békefi and Váradi [
24], a better understanding of the principle of multifunctional aquaculture and the more systematic application of the various elements of multifunctionality by farmers may contribute to the better placement of pond fish farms in an agroecosystem and improve their viability in the long term. Multifunctionality is often equated with diversification, defined as the adoption or wider application of new species, breeding types and cultural systems [
28], as well as various non-fish farming activities, such as the operation of angling ponds, small shops, restaurants or even hotels (depending on the business opportunities) [
24,
25,
29,
30]. However, multifunctionality is a broader concept than diversification. In addition to activities/functions that are important from the point of income creation, it also includes all external effects and non-commodity outputs of actions taken, including negative ones. In simplified terms, the multifunctionality of fishponds can be defined as ecosystem services viewed from the perspective of aquaculture farms. However, the term “ecosystem services” has been widely used in aquaculture literature [
4,
8,
31,
32] and in EU legal regulations [
33], and therefore it is also used in this article.
The implementation of the conservation objectives is associated with several limitations in the management of ponds, lower fish production, higher fish losses and even damage to ponds caused by protected animals. The European Maritime and Fisheries Fund (EMFF) supports aquaculture methods in line with specific environmental needs and subject to specific management requirements resulting from the designation of Natura 2000 sites, as well as aquaculture activities involving the protection and improvement of the environment and the traditional characteristics of aquaculture. Support is provided in the form of annual compensation for the added costs incurred and/or income foregone [
33]. So far, it is the only form of payment for ecosystem services in aquaculture.
Based on the literature review, a conceptual framework of the theoretical relationship between ecosystem services, multifunctionality and diversification of the traditional carp pond aquaculture was developed (
Figure 1).
Several articles on ecosystem services in aquaculture have recently been published [
4,
31,
32]. However, very few incorporated fish farmers’ perceptions of pond ecosystem services [
8,
25]. These studies allow a better understanding of the motives of fish breeders’ decisions and actions and understanding the factors which affect the acceptance of required limitations in fish management. There is another important reason for such research—developing multifunctional sustainable aquaculture requires the understanding and acceptance of those involved in aquaculture.
Starting from the theoretical framework (
Figure 1), fish farmers’ knowledge, perception and expectation of multifunctional pond management were studied. Semi-structured in-depth qualitative interviews were conducted to answer the following questions: How is the current state of carp pond aquaculture? What opportunities are there for the diversification of commercial activities? Which ecosystem services are important from a farmer’s perspective? Is the European instrument (compensating costs and/or lost income) accepted and seen as effective in making management decisions in aquaculture providing environmental services?
4. Conclusions
The study showed that fish farmers are aware that the use of traditional carp breeding methods contributes to the preservation and development of biodiversity and generates other ecosystem services. However, since traditional methods of fish breeding and rearing are not too profitable, the respondents had high expectations regarding expanding and modifying the EU system of aqua-environmental measures. The system of aqua-environmental measures was rated as too complicated and expanded. All fish farmers indicated an urgent need for compensation for production interruptions.
The conducted research showed that the size of the ponds determined the way of their management. The smallest ponds under 1 ha were used to satisfy the needs of the farm owners and their families. Commercial activity was conducted by farms with the total ponds area over 1 ha. It was diversified and included table fish, stocking material and ornamental fish production, then fish processing and providing special fishing sites for anglers. All farms carried out additional activities that were not directly related to fish production but were conditioned by ecological and other values associated with the ecosystem services of the ponds. These activities were undertaken in the field of education, agritourism and gastronomy. The most diverse activities were carried out by farms with ponds ranging from 10 to 50 ha. This size was too small to obtain a satisfactory income from traditional carp production, but it was sufficient to ensure broad opportunities for diversification. Farms with ponds over 50 ha were much less active in this respect. The study revealed a moderate willingness of the farm owners to integrate carp management with other forms of aquaculture or agriculture activity. Again, the farms with total ponds area of 10 to 50 ha were the most open in this respect. They did not exclude integration of carp breeding with the utilization of wastewater from intensive aquaculture, aquaponics or with the cultivation of cranberries and an agriculture system of crop irrigation.
Production of fish was seen as the most important pond function, regardless of their size. The research confirmed a similar general order of importance of carp pond ecosystem services: productive, environmental and then social, which was found in studies of carp pond farms in France [
8] and in Hungary [
25]. The environmental and social functions of fishponds were generally better rated on farms with smaller ponds. There was a noticeable relationship between the assessment of social ecosystem services and the diversification of activities carried out on the ponds. Ponds as a source of inspiration, know-how and a place of destination for recreation and tourism were rated the highest in farms with 10 to 50 ha of ponds, with the most diversified additional activities.
Research has confirmed that ecosystem services and multifunctionality are recognized and accepted elements of the traditional carp pond aquaculture. The implementation of this kind of aquaculture is favored both by the European policy and the ecological awareness of fish farmers.