Two experimental fish aggregating systems (fads) in the Aegean sea: their design and application

Duas bóias de aço spar foram construídas e ancoradas em 50 e 100 m de profundidade nas águas do Mar Egeu para dar apoio à pesca recreativa. O primeiro FAD foi implantado nas coordenadas 38°01'48''N 26°58'02''E, a uma distância de 3 milhas náuticas da costa. O outro ficou ancorado a 1,1 milha náutica da costa nas coordenadas 38°03'11''N; 26°59'01''E. Uma âncora (1.2x1.2x0.8 m3), pesando aproximadamente 2,76 toneladas, feita de concreto armado, foi usada para prender um FAD de peso aproximado de 1,5 toneladas. Foram realizados cálculos para determinação das conexões dos FADs, dos cabos e da ancoragem. A interação entre as forças de ondas e correntes com os FADs foi também investigada. No experimento, todas as forças (força de arrasto, força de empuxo, etc) atuantes sobre os FADs foram calculadas. É proposto que para a construção dos FADs deverão ser levados em consideração os seguintes fatores: ondas e correntes, forças relacionadas com os FADs, profundidade de implantação, sistema computacional dos moorings e cordas de amarração. Esse conhecimento proporcionará referência importante para os interessados em realizar projetos que visem aumentar o desempenho e a vida útil dos FADs.Two steel spar buoys were constructed and moored in 50 and 100 m deep of water in the Aegean Sea to support recreational fisheries. The first FAD was deployed at coordinates 38°01´48´´N 26°58´02´´E and at a distance of 3 nautical miles from the shoreline. The other FAD was moored at 1.1 nautical miles from the shoreline at coordinates 38°03´11´´N; 26°59´01´´E. An anchor (1.2x1.2x0.8 m3) weighing approximate 2.76 metric ton, made of reinforced concrete, was used to hold a FAD weighing approximate 1.5 metric ton. Hardware and connections of FADs, ropes, mooring calculation and anchor design were made. The interaction between the forces of wave and current and FADs in those waters was investigated. In the experiment, all forces (drag force, buoyancy force etc.) acting on FADs were calculated. It is proposed that the construction of the FADs should take the following design criteria into consideration: wave and current, forces related to the FADs, deployment depth, mooring hardware and ropes. This knowledge provides an important reference for stakeholders performing projects aiming to increase the performance and service life FADs

Yapay Resiflerin Rekreasyonel Dalış için Kullanımı

Scuba diving has become a burgeoning branch of the tourism service. Various activities of recreational diving do not especially necessitate natural reefs-any varied vehicle such as ship, plane and other large structures may be adequately attractive. Coastal groups are turning to these structures by the way of supplying new locations for scuba diving tourists. Despite the lack of a global database, our literature review indicated extensive use of artificial reefs for recreation in the United States, currently viewed as the pioneering puissance and professional in the field. Moreover, the Canadian and Australian governments have both promoted several “ships to reef” programs focused on recreation. However, the used of three-dimensional structures (ships, planes etc.) as artificial reefs in sensitive ecosystems such as the Mediterranean and Red Sea is not a common practice. Although scuba divers are interested in such type of structures, ships to reef is a matter of debate especially in the Mediterranean region. In Turkey, a National Artificial Reef Program was drafted in 2008, however there is no regulation at present about intentionally sinking a ship for the creation of recreational diving destinations. The aim of this review was to investigate the use of man-made structures as artificial reefs for recreational diving around the world.Aletli dalış, turizm sektörünün gelişen bir kolu haline gelmiştir. Çoğu rekreasyonel dalış aktivitesi özellikle doğal resiflere gereksinim göstermemekte, gemi, uçak ve diğer büyük yapılı araçlar da dalış için yeterince cazip olabilmektedir. Kıyısal alan kullanıcıları dalış yapan turistlere yeni yerler sağlamak için bu yapılara yönelmektedirler. Küresel bir veri tabanı olmamasına rağmen, literatür incelememiz günümüzde bu alanda öncü ve uzman olarak görülen ABD’nin rekreasyonel dalış için yapay resifleri yaygın şekilde kullandığını göstermiştir. Ayrıca Kanada ve Avustralya hükümetleri rekreasyon üzerine odaklanan “gemi resifi” programlarını geliştirmişlerdir. Ancak Akdeniz ve Kızıldeniz gibi hassas ekosistemlerde üç boyutlu yapıların (gemi, uçak vb.) yapay resif olarak kullanılması yaygın bir uygulama değildir. Her ne kadar dalgıçlar bu tür yapılara ilgi duyuyor olsalar da, gemi resifleri özellikle Akdeniz’de tartışma konusudur. Türkiye’de bir “Ulusal Yapay Resif Programı” 2008 yılında hazırlanmıştır, fakat programda rekreasyonel dalış alanları oluşturmak için kasten gemi batırma hakkında bir düzenleme bulunmamaktadır. Bu derlemenin amacı, dünya çapında rekreasyonel dalış için insan yapımı yapıların yapay resif olarak kullanımını araştırmaktır

Comparison of fish community structure on artificial reefs deployed at different depths on turkish Aegean sea coast

A profundidade da implantação de recifes artificiais é uma das questões mais importantes no planejamento de etapas e do futuro êxito. A maior parte dos estudos visando determinar a comunidade de peixes em volta de recifes artificiais foi realizada, principalmente , a profundidades de 10-25m no Mediterrâneo e Mar Egeu. Os objetivos deste estudo são determinar e comparar a estrutura da comunidade de peixes em volta de recifes artificiais que foram implantados a profundidades de 20, 30 e 40 m. A técnica de censo visual foi usada para determinar as espécies e obter uma estimativa do número e tamanho dos peixes. Não houve nenhuma diferença estatística (p> 0.05) entre as profundidades, na média da biomassa de peixes e no número de indivíduos. Entretanto, a média do número de espécies foi significativamente maior nos 20 m em comparação com as profundidades de 30 m e de 40 m (pDeployment depth of artificial reefs is one of the most important issue in planning stage and future success. Most of the studies aimed at determination of fish community around artificial reefs were conducted mainly 10-25m depths in Mediterranean and Aegean Sea. The goals of this study are determine and compare of fish community structure around artificial reefs which deployed 20, 30 and 40 m depths. Underwater visual census technique was used to determine fish species, number of individual and size estimation. There was no statistical difference (p>0.05) in mean fish biomass and number of individual between the depths. But mean species number was significantly greater on 20 m in comparison to 30 m and 40 m depths (

Tracking aquatic animals for fisheries management in European waters

Acoustic telemetry (AT) has emerged as a valuable tool for monitoring aquatic animals in both European inland and marine waters over the past two decades. The European Tracking Network (ETN) initiative has played a pivotal role in promoting collaboration among AT researchers in Europe and has led to a significant increase in the number of tagged and observed aquatic animals in transboundary European waters. While AT benefits decision-making and delivers essential data to management bodies, its potential for management decision-making mechanisms has yet to be fully harnessed. We reviewed existing research, studies, and organisational initiatives related to aquatic animal tracking and their utility in fisheries management in European waters. We found that AT has already contributed to many aspects of fisheries management, such as improved understanding of stock dynamics, identification of critical habitats, assessment of migration routes, and evaluation of the effectiveness of conservation measures. However, broader utilisation of tracking technologies is needed. By leveraging the full potential of AT, managers can make more informed decisions to protect, restore, and sustainably manage European waters and creatures that live therein

Evaluation of fish fauna associated with experimental artificial reefs in Hekim Island in Izmir Bay (Aegean Sea, Turkey).

Fish fauna before and after reef deployments in Hekim Island was studied. Furthermore, differences of fish fauna between 9m and 18m reef groups were also evaluated. Underwater visual census technique was used to determine fish species richness and abundance. Differences in fish species richness, abundance and diversity between before and after reef deployment and 9m and 18m reef groups were revealed using correspondence analysis. Increasing of fish species richness and abundances after reef deployment was found significant. Differences in fish richness and abundance between 9m and 18m reef groups were not significant. It was found that seasons have an important effect on fish composition around artificial reefs