Population abundance and growth parameters of an exotic bivalve species, Anadara kagoshimensis, in the Southwestern Black Sea

Blood cockle (Anadara kagoshimensis ) is an Indo-Pacific species that later entered the Black Sea. The abundance of A. kagoshimensis, which is not subjected to commercial fishing, is important in terms of food competition with other bivalvia species. Baby clam (Chamelea gallina) together with the A. kagoshimensis are dominant bivalve species found in the sandy and muddy areas off the coastal waters of the Black Sea. In this study, specimens of A. kagoshimensis have been recognized by morphological analysis and also confirmed by molecular characterization. Furthermore, the abundance and growth parameters of A. kagoshimensis were investigated in the Southwestern Black Sea. Blood cockles were sampled between February 2011 and December 2012, seasonally. According to the Von Bertalanffy Growth Parameters (VBGP) the results were L infinity = 81.96 mm, K = 0.32 year-1, t0 = -0.22 year, and nonseasonal L infinity = 84.32 mm, K = 0.31 year-1, t0 = -0.21, WP = 0.65, ts = 0.15. The growth pattern showed the slope [b] = 2.96-3.01 in 2011 and 2012. The stock size was estimated according to two different years in 5 different subareas (Cide, Inebolu, Turkeli, Ayancik, and Sarikum) and by 4 different strata (0-5 m, 5-10 m, 10-15 m, and 15-20 m). Considering subareas, the A. kagoshimensis population in all subareas increased significantly in a single year. Compared to other regions, Inebolu was the main highly distributed area of the A. kagoshimensis, and also the estimated stock size was the highest in the region. Due to food competition with other commercial species (mainly Chamelea gallina) A. kagoshimensis is an ecology important species for the Southern Black Sea habitats. It is aimed to make contributions to Good Environmental Status (GES) and fisheries management in the region

Black sea aquaculture: Legacy, challenges & future opportunities

Responsible aquaculture, the farming of aquatic organisms, is a sustainable strategic sector for land and coastal communities. It significantly contributes to food security and enhancement of economic development; it provides employment opportunities and often contributes to the ecological services provided by the environment. According to the Food and Agriculture Organization of the United Nations (FAO), the contribution of aquaculture to the global food security is widely demonstrated by an astounding industry growth of 7.5% per year since 1970. In 2018, aquaculture reached the all-time highest production of 114.5 million tonnes in live weight with a total farm gate sale value of USD 263.6 billion. This makes aquaculture a key player within the Blue Growth concept and a strong contributor to some of its key Sustainable Development Goals (SDG). This is particularly true in geographical areas where dependence of local economies on fishery products is high, and yet access to sustainable landings is hampered by ecological barriers. One such area is represented by the Black Sea basin. Whilst the Black Sea annual capture fishery production has varied considerably since 1990 and its current landings are significant, growing attention is currently given to boost aquaculture development along the Black Sea bordering countries, with marine aquaculture being considered as an important contributor to the total fisheries production. Nonetheless, aquaculture development in this region is not homogenous and its development has, so far, been limited by environmental, economic, social, and more generally governance issues. This paper, for the first time, attempts to provide a comprehensive fresh outlook of the aquaculture sector in the Black Sea, stressing the importance of regional cooperation as an essential pillar to support the sustainable development of the industry. The paper addresses aquaculture in the Black Sea from different perspectives: it outlines the key characteristics of the Black Sea environment; it discusses the most common farmed aquatic species and the potential for new ones; it frames the national approaches to aquaculture development, sharing information about success stories, while shedding light on the main challenges and priorities ahead. This collective endeavour will represent a helpful contribution to Black Sea riparian countries to answer the many questions they have, and expectations they hold from the aquaculture sector.Additional co-authors: Dilek Fidan, Linda Fourdain, Marco Frederiksen, Archil Guchmanidze, Housam Hamza, Jessica Harvey, Magda Nenciu, Galin Nikolov, Victor Niţă, Muhammed Doğan Özdemir, Elitsa Petrova-Pavlova, Gabriel Popescu, Ferit Rad, Şafak Seyhaneyildiz Can, John A. Theodorou, Behnan Thomas, Nicolò Tonachella, Ekaterina Tribilustova, Irina Yakhontova, Ahmet Faruk Yesilsu, Güzel Yücel-Gie

Trabzon ilinde su ürünleri üretimi ve pazarlama yapısı

TEZ7042Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 2008.Kaynakça (s.89-93) var.xi, 115 s. : rnk.res. ; 29 cm.In this study, Trabzon province's fishery and marketing structures were investigated. How the maritime lines provide fishery products by aquaculture and catching, possessed or not possessed facilities and the encountered problems during the production process were revealed. Also, the data was gathered related to aquaculture marketing structure and organization in Trabzon province by analyzing the paths of product from the producers to consumers in all stages. While the manufacturing structure of the industries were being analyzed , quite a few factors were taken into consideration like, industry owners' educational background, the social institution membership, preference reasons for the job, the encountered problems in production, organizational status, possibilities for investment, invested areas, the staff who works in industry, expectation and views for the future, marketing channels, marketing brokers, marketing groups and efficiency of marketing organization. By the research result, it was found that marketing services were inadequate in terms of competition and financing, marketing news wasn't announced and marketing margin was high. It was ascertained that marketing organization were inactive in the research area.Bu araştırmada, Trabzon ilindeki su ürünleri üretim ve pazarlama yapısı incelenmiştir. Su ürünlerini yetiştiricilik ve avcılık/balıkçılık yoluyla sağlayan işletmelerin üretimlerini nasıl gerçekleştikleri, sahip olunan veya olunamayan olanaklar ve üretim esnasında yaşanan sorunlar ortaya çıkarılmıştır. Aynı zamanda ürünün üreticiden tüketiciye kadar olan tüm aşamalardaki yolları incelenerek, Trabzon ilindeki su ürünleri pazarlama yapısı ve organizasyonunun etkinliği hakkında bilgiler edinilmeye çalışılmıştır. İşletmelerin üretim yapıları incelenirken işletme sahiplerinin eğitim ve öğrenim durumları, sosyal güvenlik kuruluşuna üyelikleri, mesleğin tercih edilme sebepleri, üretimde karşılaşılan problemler, örgütlenme durumları, yatırım yapabilme olanakları, yatırım yapılan alanlar, işletmelerde çalışan personel, işletmelerin geleceğe bakış açıları, pazarlama kanalları, aracılar, pazarlama organları, pazarlama marjı pazarlama organizasyonun etkinliği vb. birçok faktör incelenmiştir. Araştırma sonucunda pazarlama hizmetleri, rekabet ve finansman açısından yetersizlikler olduğu, pazarın saydam olmadığı ve pazarlama marjının yüksek olduğu tespit edilmiştir. Araştırma alanında pazarlama organizasyonu etkin olmadığı belirlenmiştir.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi Tarafından Desteklenmiştir. Proje No:ZF2007YL5

Abundance of striped venus (Chamelea gallina L., 1758) stocks in different regions (Sinop-Kastamonu) with seasonal growth, and socio-economic analysis of fishing boats.

TEZ12403Tez (Doktora) -- Çukurova Üniversitesi, Adana, 2016.Kaynakça (s. 127-144) var.XIII, 158 s. :_res. (bzs. rnk.), tablo ;_29 cm.Bu çalışmada, Türkiye balıkçılığında önemli bir yere sahip olan türlerden biri olan beyaz kum midyesinin (BKM) Karadeniz’de avcılığına uygun alanlardaki stok miktarı, stoğun demografik dağılımı, boy kompozisyonu ve temel popülasyon parametrelerinin belirlenmesi hedeflenmiştir. Ayrıca, bu kaynaktan faydalanan balıkçıların sosyo-ekonomik yapısının ortaya konulması amaçlanmıştır. Çalışmada, taranan alan yöntemi uygulanarak hidrolik dreç ve mekanik dreç kullanılarak örneklemeler yapılmıştır. Çalışma alanı beş alt bölgeye ayrılmıştır. Bu alt alanlarda 2011 yılında yapılan örneklemede stok miktarları; Cide’de 11.723,58±5.167,262 ton, İnebolu’da 35.082,943±27.510,947 ton, Türkeli’de 10.077,05±4.970,683 ton, Ayancık’da 3.304,361±3.215,101 ton ve Sarıkum’da 1.431,296±1.703,504 ton olarak tahmin edilmiştir. Stok miktarları 2012 yılında ise sırasıyla 13.820,408±6.977,857 ton, 34.841,937±14.623,708 ton, 8.148,269±5.006,737 ton, 3.420,716±3.093,67 ton ve 2.023,743±2.832,63 ton olarak bulunmuştur. Von Bertalanffy Büyüme Parametreleri Lt=32,28[1-e–0,249(t+0,262)], Wt=9,74[1-e–0,249(t+0,262)]2,9072 bulunmuştur. C. gallina’nın boy-ağırlık ilişkisi 2011 yılında W=0,0004L2,9011, 2012 yılında ise W=0,0004L2,9072 olarak bulunmuştur. C. gallina’nın negatif allometrik büyüme gösterdiği belirlenmiştir. BKM avcılığı yapan 27 tekne sahibi ile yapılan çalışmada tekne sahiplerinin balıkçı bir aileden geldikleri, mesleki deneyimlerinin ortalama 24,29 yıl olduğu bulunmuştur. Teknelerin gayrisafi üretim değeri ortalama 220.861 TL’dir. Tekne sahiplerinin brüt karı 104.953 TL, net karı 77.595,5 TL’dir. Ekonomik rantabilite (ROI) %21,02, mali rantabilite %21,35 ve sermaye devir oranı %59,84 olarak hesaplanmıştır. Tekne boyunun ve motor gücünün büyüklüğü tekne sahiplerinin gelirleri üzerinde etkili değildir (p>0,05). Denize çıkılan gün sayısı ile balıkçılık geliri arasında pozitif yönlü bir korelasyon vardır (p0.05). Positive correlation was observed between the number of the days in the sea and fisheries income (p<0.05). The results of the study indicated that two years of fallow period did not result in a big increase in the stock size. Environmental factors and predator effect have high impact on the increase of the stock size and the changes occurring in these conditions should be considered in the fisheries management. Some vessels could make loss in the absence of tax free fuel subsidies independent from the total catch amount of the fishing fleet. An increase in the number of fishing vessels would decrease the average income per vessel. This situation could increase the pressure on the resources. For this reason, the number of vessels should be limited with 30-35 vessels not to increase the pressure on the resources as well as not to decrease the average income per vessel.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi tarafından desteklenmiştir. Proje No: SUF2012D2

The invasive mollusk Rapana venosa (Mollusca: Neogastropoda: Muricidae) in the mid-southern Black Sea: Distribution, growth, and stock structure

The rapa whelk, Rapana venosa (Valenciennes, 1846), known also as the veined rapa whelk or the Asian rapa whelk, settled in the Black Sea in 1940 and within the past 30 years has become an important economic contribution to local fishers along the coastline. This study examines the annual change in biomass, population structure, and interaction of the species with the ecosystem of rapa whelk in the mid-southern Black Sea. The samples were collected monthly in 2011 and 2012 by hydraulic dredge at different sites. Stock biomass was estimated at five different subregions and along four depth contours. In 2012 the biomass of rapa whelk increased significantly in in all subregions compared with the previous year sampling. Food availability is the main factor for species distribution, and in parallel, striped Venus clams, Chamelea gallina (Linnaeus, 1758), the main food source for rapa whelks, was significantly concentrated in the study area. The von Bertalanffy growth parameters (VBGP) were expressed as Lt = 121.78(1 − e−0.246(t + 0.33)). As a fisheries management point, our results highlight the overpopulation of rapa whelk in the region

A participatory approach to tagging and monitoring as an initial step in developing a sturgeon conservation strategy along the Turkish Black Sea Coast

The objective of this study was to organise a national mechanism that would allow to effectively promote and control the gentle handling and release of accidentally caught sturgeons with the participation of the fishery while at the same time testing the effectiveness of such measures through tagging and continuous monitoring. A second objective was to develop through this exercise a participatory conservation strategy for sturgeons which is jointly executed by the research institutions, governmental agencies and commercial fishery. The samples of Acipenseridae which were captured accidentally in the fishing nets from the commercial fishers were released to sea after tagging with plastic T-bar tag and all the information about the fish species such as fish weight and length, capture locality, depth were recorded. Within these applications, carried out in collaboration with the Fisheries Cooperatives and fishermen in the Black Sea region, 99 fish (9, 22, 48 and 20 for the years 2006-2009, respectively) were tagged and released to the sea. Five of the tagged fish were re-captured and released again after recording the information on the tags

A participatory approach to tagging and monitoring as an initial step in developing a sturgeon conservation strategy along the Turkish Black Sea Coast

The objective of this study was to organise a national mechanism that would allow to effectively promote and control the gentle handling and release of accidentally caught sturgeons with the participation of the fishery while at the same time testing the effectiveness of such measures through tagging and continuous monitoring. A second objective was to develop through this exercise a participatory conservation strategy for sturgeons which is jointly executed by the research institutions, governmental agencies and commercial fishery. The samples of Acipenseridae which were captured accidentally in the fishing nets from the commercial fishers were released to sea after tagging with plastic T-bar tag and all the information about the fish species such as fish weight and length, capture locality, depth were recorded. Within these applications, carried out in collaboration with the Fisheries Cooperatives and fishermen in the Black Sea region, 99 fish (9, 22, 48 and 20 for the years 2006-2009, respectively) were tagged and released to the sea. Five of the tagged fish were re-captured and released again after recording the information on the tags

Small-scale fisheries in the southern Black Sea: Which factors affect net profit?

Small-scale fisheries (SSF) is a local and community-based activity that can be traced back to ancient times, and thus, closely related to the history of humankind. However, large-scale fisheries have grown tremendously, approaching an industrial sector in the last century, due to their socio-economic and political properties, including both national and international aspects. This progress towards industrial-scale fisheries led to the involvement of scientific research, first aiming to improve production efficiency, and then, to protect ecosystems as resources exploited for fisheries activity, by mitigating their adverse impacts. During this evolutionary progress, SSF was usually neglected because of their limited production ability, and thus minimal economic contribution, until the later phase when the protection of ecosystem resources gained sufficient importance. As a result of this, many countries lack data on SSF, undermining efforts for the creation of proper policies for this type of fisheries. The aim of this study was to evaluate the productivity and the effects of some demographic characteristics, boat structures, and some cost (input) items on the net profit of SSF in the Black Sea. The eligible sample for this study consisted of 5575 small-scale fishing boats in the Black Sea. The number of fishers to be surveyed was determined as 315 using the “Simple Random Sampling” method, based on operators of boats < 12 m, i.e., boats in the SSF. Questionnaires were conducted face-to-face with fishers. In this study, it was tested if six parameters were investigated to determine whether they had a significant effect on net profit in SSF. These parameters were: (1) engine power; (2) number of fishing days; (3) boat length; (4) consumption of fuel in fishing; (5) education level of fishers; and (6) overall professional experience of fishers. To do so, Simple Linear Regression Analysis was performed to determine the effect of the data considered as independent variables when the net profit was set as the dependent variable. Atlantic bonito, Sarda sarda (Bloch, 1793); whiting, Merlangius merlangus (Linnaeus, 1758); rapa whelk, Rapana venosa (Valenciennes, 1846); and turbot, Scophthalmus maximus (Linnaeus, 1758) were the most important commercial fish species for small scale fishing. When catch per boat in SSF was evaluated, Kırklareli province ranked first with 97 007 kg, with Atlantic bonito (44 778 kg) being the most common species caught. Samsun had the second-largest catch per boat with 91 761 kg. The total net profit of 303 boats was calculated as €1 794 938 and the mean net profit per boat was €5924. The highest per boat mean net profit (€25 909) was in Kırklareli. According to the results of the study, the number of days at the sea, boat length, engine power, and fuel cost had a significant effect on the net profit while education level and professional experience were not important in productivity. The economically-fragile SSF sector may need some kind of supporting subsidy. It would be beneficial to provide support to the majority of fishers active in the SSF in terms of complementary alternative employment opportunities in the regions where they are located

Effect of a fishing closure on Chamelea gallina stocks along the Turkish coast

The striped venus clam Chamelea gallina (SVE), plays an important role as an infaunal filter-feeder in the ecosystem, besides an important economic role in the Black Sea coasts of Turkey. It is caught using hydraulic dredge boats, then processed, and the final product (frozen meat) is exported to EU countries. SVE fishing requires a special licence and regulations. Also, SVE beds were closed to fisheries for the recovery of stocks for 2 years. In the study, SVE beds were investigated during the closed season over two years to assess stock density. Additionally, the number of macrobenthic species that share the same habitat as the SVE was determined. The sampling area was divided into five sub-areas and four strata by depth and then stratified random sampling was applied to collect data. In 2011, SVE stock sizes in the sub-areas were 11,723.58 +/- 5167.262 tons (Cide), 35,082.94 +/- 27,510.95 tons (Inebolu), 10,077.05 +/- 4970.68 tons (Turkeli), 3304.36 +/- 3215.1 tons (Ayancik) and 1431.3 +/- 1703.5 tons (Sarikum). In 2012, these estimated stocks were 13,820.41 +/- 6977.86 tons, 34,841.94 +/- 14,623.71 tons, 8148.27 +/- 5006.74 tons, 3420.72 +/- 3093.67 tons and 2023.74 +/- 2832.63 tons, respectively. However, the estimated SVE total biomass did not change significantly during the period when the fields were closed (P > 0.05). The results indicate that length-weight relationship parameters varied of b from 2.9011-2.9072 in two years. Shell damage during fishing, environmental factors, food competition and consumption by the main predator all have a significant impact on stock densities, and changes occurring in these conditions should be considered in fisheries management

Effect of mesh size in monofilament and multifilament gillnets on catch efficiency in the Black Sea whiting (<i>Merlangius merlangus</i>) fishery

Gillnets are widely used fishing gear for targeting various fish species. Gillnet fisheries use different gear configurations such as different mesh sizes and number of netting twines (mono- or multifilament) depending on the species targeted. Gillnet fishery targeting whiting (Merlangius merlangus) is one of the economically important year-round fisheries in the Black Sea. However, large bycatch of whiting below minimum landing size (MLS) has led to a stock decrease, questioning sustainability of this fishery. This study evaluated how netting twine construction and mesh size can affect the capture probability of whiting. The results showed that changes in gillnet mesh size significantly affect the capture probability with increased mesh size reducing the average capture probability of undersized whiting from around 60%–5%. The results showed no significant differences in the average catch efficiency between monofilament and multifilament gillnets of the same mesh sizes; however, monofilament gillnets showed an increased catch efficiency for some length classes of whiting &gt; MLS. Based on these results, use of 32 or 34 mm mesh size monofilament gillnets is advisable for sustainable whiting fisheries management in the Black Sea