An overview of aquaculture in Turkey: With emphasis on sea bass and sea bream

Abstract

Aquaculture is a relatively recent industry in Turkey, enjoying great potential for development. Both freshwater and marine aquaculture are being practised in over 800 operational units. Rainbow trout (Oncorhynchus mykiss), Sea bream (Sparus aurata), Sea bass (Dicen‐trarchus labrax), comprise 90% of the total production, together with Atlantic salmon (Salmo salar), Common carp (Cyprinus carpio), Shrimp (Penaeidae spp.) and Mussel (Mytilus gal‐loprovincialis). Total aquaculture production reached 45 450 t in 1998, constituting 9% of total national fisheries production. Sea bass and sea bream farms are located along Aegean Sea and Mediterranean coasts and comprised 16% of the total number of aquaculture enterprises and 30% of total aquaculture production in 1997. Supplies of these two species have been steadily increasing in Turkey and other producing countries since 1990 resulting in market saturation and declining prices both locally and internationally. Mediterranean species including Epinephelus spp., Puntazzo puntazzo and Pagrus pagrus, are considered to be new candidates offering good prospects for mariculture.     

Are farmed European seabass (Dicentrarchus labrax) prices in European Union markets affected by Turkish exports of farmed European seabass?

Abstract

Often, increases in farmed seabass and seabream production surpluses from Turkey and Greece have been blamed to lead to price declines and aquaculture sector crises. In this study, we investigate whether Turkish exports of farmed European seabass affect prices of European Union (EU) farmed European seabass. This is done by examining the existence of market integration between the prices of Turkish exports of farmed European seabass into the EU and the prices of farmed European seabass commercialized in wholesale markets in Barcelona, Madrid and Paris. Market integration and competition studies in fisheries and aquaculture products have generally focused on analyzing substitutability between species and between wild and farmed conspecifics. Few studies have focused on analyzing market integration between different geographic areas. Market integration analyses between different geographic areas have proven useful in anti-dumping investigations. Results show the lack of market integration between EU imports of Turkish farmed European seabass and main EU wholesale markets; in other words, farmed European seabass prices in EU markets do not seem to be affected by export prices of Turkish farmed seabass.     

Effects of Sowing Date and Chitosan on Some Characters of Canola (Brassica napus L.) Genotypes

Journal of Crop Science and Biotechnology - Changes in the environment that are associated with different sowing dates can be expected to alter canola (Brassica napus L.) growth and development....     

Prevalence of Linguatula serrata nymphs in one-humped camel (Camelus dromedarius) in Najaf-Abad, Iran

The prevalence of Linguatula serrata nymphs in livers and mesenteric lymph nodes (MLNs) of 400 camels of different sex and age groups was investigated. The lymph nodes and livers were examined macroscopically. A digestion method was also applied for investigation of liver samples. The MLNs in 84 camels out of 400 (21.0%) and the livers of 18 camels out of 400 (4.5%) were infected by L. serrata nymphs. The infection rate increased with age (p<0.01). No significant difference was observed between the prevalence in males and females (p>0.1). It is concluded that consumption of raw or under-cooked camel liver may result in nasopharyngeal linguatulosis in humans.     

Mechanisms of aluminum‐induced growth stimulation in tea (Camellia sinensis)

Beneficial effects of aluminum (Al) on plant growth have been reported for plant species adapted to acid soils. However, mechanisms underlying the stimulatory effect of Al have not been fully elucidated. The aim of this study was to determine the possible contribution of photosynthesis, antioxidative defense, and the metabolism of both nitrogen and phenolics to the Al‐induced growth stimulation in tea (Camellia sinensis [L.] Kuntze) plants. In hydroponics, shoot growth achieved its maximum at 50 μM Al suply (24 μM Al³⁺ activity). A more than threefold increase of root biomass was observed for plants supplied with 300 μM Al (125 μM Al³⁺ activity). Total root length was positively related to root Al concentrations (r = 0.98). Chlorophyll a and carotenoid concentrations and net assimilation rates were considerably enhanced by Al supply in the young but not in the old leaves. Activity of nitrate reductase was not influenced by Al. Higher concentrations of soluble nitrogen compounds (nitrate, nitrite, amino acids) and reduction of protein concentrations suggest Al‐induced protein degradation. This occurred concomitantly with enhanced net CO₂‐assimilation rates and carbohydrate concentrations. Aluminum treatments activated antioxidant defense enzymes and increased free proline content. Lowering of malondialdehyde concentrations by Al supply indicates that membrane integrity was not impaired by Al. Leaves and roots of Al‐treated plants had considerably lower phenolic and lignin concentrations in the cell walls, but a higher proportion of soluble phenolics. In conclusion, Al‐induced growth stimulation in tea plants was mediated by higher photosynthesis rate and increased antioxidant defense. Additionally, greater root surface area may improve water and nutrient uptake by the plants.     

Metabolic blood profile of beef heifers during oestrous and non‐oestrous states

Haematological metabolic profiles in heifers could contribute to the development of proxies for oestrous detection and provide clues to further characterize biological changes during oestrus. One hundred and seven beef heifers were observed for oestrous behaviour twice daily for 124 days. Feed intake and productive performance (body weight and composition) traits were measured, and feed efficiency was determined using residual feed intake (kg DM/day). Blood plasma samples were collected when signs of oestrus were observed and every 30 ± 2 days. Heifers were considered in oestrus (n = 71) when plasma progesterone concentrations were <0.6 ng/ml. Least square means of blood metabolic parameters were compared between oestrous and non‐oestrous states and within oestrous groups according to performance traits and age. Heifers in oestrus exhibited higher concentrations of alkaline phosphatase, aspartate aminotransferase (AST), beta‐hydroxybutyric acid, creatine kinase (CK) and triiodothyronine (T3) than heifers in non‐oestrus. Heifers in oestrus revealed lower osmolality and concentrations of calcium, sodium and total protein than during non‐oestrus. Younger (and smaller) heifers had greater concentrations of CK, gamma‐glutamyl transferase (GGT), glucose and sodium than the older heifers. Heifers with lower fatness had increased osmolality and concentrations of cholesterol, CK, phosphorus, sodium and reduced T3 levels. Feed efficient heifers had greater levels of AST, cholesterol and GGT than inefficient heifers. Blood plasma parameters may be complementary to oestrous detection upon further validation; effects of age, feed efficiency, body size and body composition should be considered to optimize this haematological assessment.     

ANGIOGRAPHIC APPEARANCE OF COMMON CAROTID COLLATERAL CIRCULATION IN THE GOAT RESULTING FROM PROSTHETIC GRAFT IMPLANTATION

Carotid arteriography was performed in six normal goats. The same procedure was performed on these six and 112 other goats at various time intervals after placement of an arterial graft in one or both carotid arteries. An arterial catheter was introduced into the femoral artery and advanced to the origin of the brachiocephalic trunk with the aid of image-intensified fluoroscopy. Hand-injection of the contrast medium resulted in complete opacification of both common carotid arteries in normal animals. Opacification of one or both of the vertebral arteries was usually seen in the goats with prosthetic grafts. The left vertebral artery was seen more often than the right, and when both vertebral arteries were seen together, the left was often larger. This angiographic method proved to be reliable for opacifying both common carotid arteries from their origin on the brachiocephalic trunk to the cranial cervical region. No clinical problems were associated with either the catheterization procedure or with the permanent ligation of the catheterized femoral artery.