10.6 Interactions among aquaculture, capture fisheries and the environment in coastal lagoon management

Most parts of the lagoons are suffering of severe pollution impacts, especially the Bizerte and Tunis lagoons, which receive organic and industrial outfalls and urban wastes, including sewages, respectively. The Ichkeul lake seems to be mostly influenced by its surrounding watersheds and, to a lesser degree, by solid wastes coming from these areas. No pollution oriented survey nor exhaustive studies have ever been realized on the identification of the possible damages and to establish the current state of confinement within the lagoon, something that could allow identifying the suitable zones for fish and/or other species rearing.

The lagoon of Bizerte receives pollutants from the surrounding agriculture and industrial areas. A decontamination-oriented study is being undertaken under the supervision of the National Agency of Environment Protection (ANPE), but unfortunately this study does not sufficiently take into consideration aquaculture activities.
As far as marine capture fisheries are concerned, some signs of overfishing seem to be related to the important decrease of global production and of some fish species which are becoming drastically scarce. Unfortunately, there are no studies oriented towards stock assessment for the lagoons, instead, several studies are going to be done in relation to the small-scale pelagic and demersal fish. As a result, it is not easy to estimate to what extent lagoon fish stocks are moderately or overfished.

10.6.1 Interactions among different fishers groups and conflicts between fishers/fish farmers and public or private stakeholders

The only lagoon that hosts aquaculture activities is the Bizerte one, with five shellfish farms located within a limited zone close to the lagoon-sea communication. Severe conflicts exist between the farmers and the fishers in terms of space and possible impacts on the free circulation of the boats and pollutants release. The regional fisheries authorities are trying to manage and settle such conflicts. The situation must be addressed in a sustainable manner, something that could be reached by the establishment of a plan including aquaculture allocated zones.
As far as the other lagoons are concerned, the main conflicts are related to the relationship between fishers and the private companies to which exclusive licences were granted for a certain time (30 years at maximum). The main weaknesses consist in the absence of professional organizations on one side and the non-compliance of the companies toward their commitments in matter of good practices and respect for the environment (their main concern is to increase their profit) on the other. The Ichkeul lake represents a specific case with its special water regime, which is highly impacting the fisheries and possible aquaculture activities. An exhaustive study is being performed to manage sustainably the water resources, taking into account the development of fish culture (Eco Ichkeul, 2009).

10.6.2 Competition for space (location of aquaculture facilities in fishing grounds, existence of “planning management” for lagoon areas, etc.)

No serious planning of space and water bodies was done yet. It is a matter of urgency if the public authorities seriously think about the necessity to save the lagoons, to enhance their productivity and to conserve their biodiversity.

10.6.3 Product interaction on the market (product from aquaculture vs from capture fisheries; presence of private/ public label for fishery products)

Aquaculture is a relatively recent activity, which fills the gap of the lack of similar fish of sea origin (seabass and seabream) on the local market. The preference of the consumer goes to aquaculture products, which are cheaper. At the same time, no official label exists for fish products but the difference between the sea fish and the aquaculture ones is easily perceived by the consumer. At the export level, some lagoon products are highly appreciated, especially eels and prawn, on the Spanish and Italian markets.
10.6.4 Environmental effects of aquaculture and capture fisheries on biodiversity conservation
No specific studies were performed to assess the impacts of aquaculture on biodiversity. With regard to fisheries, several researches and studies were performed to evaluate the effects of fishing gear and practices on the coastal zones, especially in the gulf of Gabes.

10.6.5 Juveniles/spat collection in the wild for culture and/or restocking purposes

Capture-based aquaculture (capture of juveniles in the wild) is oriented to restocking purposes in the inland water bodies, especially dams and reservoirs.

10.6.6 Genetic impact of restocking actions / escape events on wild stocks

No specific studies were realized to assess the effects of fish escaping since those events are not reported.

10.6.7 Elements for green accounting and ecological services

The main source of energy is of fossil origin, especially gasoil. Special prices are granted to the coastal fishers (20 percent less than the current price). The gasoil tonne costs about US$ 700. No renewable energy is used.
The most important taxes and tributes paid for using natural resources (i.e. waste treatments, packaging, advancement/requalification/rebuilding of natural/public areas). A global tax is being paid by the water users; the relevant fees are indexed to the water consumption volumes. The packaging boxes used to sell fresh fish are made of polyethylene. The clams (mussels and oysters as well as Tapes decussatus) are packaged in plastic and/or jute bags. The sanitary control on fish flesh is currently exercised by the veterinary services, which are depending on the Ministry of agriculture and environment
The control on production facilities is under the aegis of the General Directorate of fisheries and aquaculture through its regional services.
No significant outputs could be drawn up from the lagoon ecological goods and services for the moment, but several stakeholders are claiming more attention toward those sensitive media, especially with regard to their exploitation for the benefit of the local work forces (the lagoon surrounding population suffers from unemployment and relative poverty).
There is significant awareness about the importance of lagoons in matters of economic, social and environmental interest, especially from the side of NGOs and civil society as a whole. This aspect was raised during the meetings which were organized with the aquaculture stakeholders when setting the main elements of the sustainable development of aquaculture (in the framework of the GFCM CAQ working group on sustainability of aquaculture development),
but something should be done to orient that interest and to focus on the urgent matter of lagoons restoration and improvement.