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1.
We investigate empirically market interactions in the Turkish wild and farmed sea bass and sea bream markets. For gilthead sea bream and European sea bass, we conduct a Granger causality test between the prices of the wild and farmed products, based on the estimation of a vector autoregressive model. Our data set consists of annual fish prices from 1996 to 2016. Our empirical results show that the wild and farmed sea bass are neither substitutes nor complements: the markets for each product are independent. However, in the case of sea bream, the price variations for farmed sea bream have a causal impact on the price of wild sea bream. Moreover, the price of wild sea bream Granger-causes the price variation of farmed sea bream. Thus, the wild and farmed sea bream markets are integrated.  相似文献   

2.
ABSTRACT

Aquaculture is contributing at an increasing rate to the world seafood supply. The interaction between fisheries and aquaculture is especially important for the seafood market where supply of wild and farmed fish can affect price dynamics. We examine market interactions in the French fresh sea bass and sea bream markets. We test for long-term price parity between farmed and wild products for these two species, applying a bivariate cointegration approach to market delineation. We also conduct the Law of One Price (LOP) test between price series. Our data base consists of monthly domestic price series for fish purchased by French households from 2007 to 2012. Our empirical results show that the fresh fish markets for whole wild and farmed sea bream are partially integrated, yet those for whole wild and farmed sea bass are not integrated. The substantially higher price for wild sea bass relative to farmed sea bass suggests that consumers may be more sensitive to seafood production processes when it comes to higher-value species.  相似文献   

3.
Trace elements in otoliths of sea bass (Dicentrarchus labrax L.) and sea bream (Sparus aurata L.) from fish farms and coastal wild populations in the western Mediterranean Sea were analysed by inductively coupled plasma-mass spectrometry. Results showed that concentrations of Mg, K, and Mn differed significantly between wild and farmed sea bass, while concentrations of Mg, K, Mn, Fe, Zn, Sr, and Ba varied significantly between wild and farmed sea bream. Discriminate analysis and cross-validation classification showed that the trace element profile in otoliths can be used to separate farmed fish from wild stocks with high accuracy on both sea bass (individuals correctly classified: 90.7 %) and sea bream (individuals correctly classified: 96.6 %). Moreover, trace elements in otoliths resulted to be useful to discriminate among wild fish stocks within each species.  相似文献   

4.
European sea bass (Dicentrarchus labrax) and gilthead sea bream(Sparus aurata) are amongst the most important finfish speciescultured in the Mediterranean region. Production of these species isnowadays a well-controlled process, but knowledge of their nutritionalrequirements is still very limited. Nevertheless, a considerable amountof data has been accumulated in recent years, and the purpose of thispaper is to review the recent advances on the nutritional requirementsof sea bass and sea bream. The optimum protein to energy ratio of thediets of sea bass and sea bream seem to be higher than for salmonids,and there is some evidence that high dietary lipid levels have nobeneficial effects on fish performances. Although the essential aminoacid requirements were estimated by the ideal protein method, data basedon the dose-response method is only available for a few amino acids.Essential fatty acid requirements were estimated for sea bream juvenilesbut data is lacking for sea bass. Vitamin and mineral requirements ofthese species are practically unknown. Although the importance ofbroodstock nutrition on gonadal development, spawning and egg quality isrecognized, few studies were done to elucidate these aspects. The recentdevelopment of microparticulate diets for larvae will contribute to theaccurate evaluation of their nutritional requirements.  相似文献   

5.
European sea bass (Dicentrarchus labrax) is a widely consumed marine fish in Mediterranean areas, and different farming techniques are applied for fish culturing to satisfy the growing demand for seafood. The aim of this study was to investigate the effects of conventional and organic feed on the quality of cultured European sea bass (Dicentrarchus labrax) collected during the growth period. The concentrations of ash, moisture, essential macro‐elements (Ca, K, Mg, Na and P), micro‐elements (Co, Cr, Cu, Fe, Mn, Ni and Zn) and toxic elements (As, Cd, and Pb) were determined in feeds and in fillets of cultured fish. The results were compared to those obtained from wild sea bass. Results showed that the differences between organic diet‐fed and conventional diet‐fed sea basses varied in relation to the specific element measured and the growth period. The former showed higher concentration of Fe, Mg and Cr, and lower Na content. The amount of P, Na, Fe, Cu and Cr in wild sea bass was significantly (P ≤ 0.05) higher than that found in farmed fish. The levels of toxic elements in cultured sea bass were always within the allowed limit for fishery products. Wild samples had significantly (P ≤ 0.05) higher content of arsenic and lead than farmed sea bass. Cultured fish represent a valuable dietary source of essential macro‐ and micro‐elements. Controlled rearing systems and feedings were related to a decrease in the presence of some toxic metals in cultured fish compared with wild fish.  相似文献   

6.
Farmed gilthead sea bream, Sparus aurata, frequently escape from the sea cages and interact with wild populations. The impact of these interactions on the wild populations will depend, in part, on differences in performance of the bream. This study compared the swimming performance of the wild and farmed fish in a current channel. The absolute critical swimming speed (Ucrit) increased with increasing size while the relative Ucrit decreased. Even at the same length there were noticeable performance differences between the individuals. The wild sea bream have significantly higher (P<0.05) absolute Ucrit performance (0.86±0.01 m s−1) than the farmed fish (0.79±0.01 m s−1) and significantly higher (P<0.05) relative Ucrit performance (4.52±0.05 BL s−1) than the farmed fish (4.21±0.05 BL s−1). The present study suggests that cultured sea bream may not have the ability to compete with wild sea bream in native seawaters.  相似文献   

7.
Parasitic nematodes of the family Anisakidae occur in the visceral cavity and surrounding tissues of many marine fish species at a prevalence as high as 100% in wild salmon samples. Human consumption of fish products containing these parasites can result in the zoonotic disease anisakiasis, and Anisakis simplex is most commonly associated with human disease. Previous studies of farmed salmon have found no anisakids in viscera or muscle, presumably because formulated feed production renders parasite larvae nonviable. However, among farmed Atlantic salmon (Salmo salar) examined by histopathology as part of a provincial government auditing program in British Columbia, Canada, 1 of 894 (0.11%) had an anisakid larva partly embedded in the wall of an intestinal cecum. Skeletal muscle is not examined as part of the government's program, but other studies have correlated anisakids in the viscera and muscle. Using anisakid prevalence in viscera as an estimate of its prevalence in muscle, the risk ratio of anisakid parasites in commercial product is 570 times less in farmed than in wild Atlantic salmon.  相似文献   

8.
王志远  李金库  李昀  王灵钰  齐鑫  李吉方  温海深 《水产学报》2023,47(8):089104-089104
为探究ncc、nkcc基因在花鲈渗透调节中发挥的作用,实验通过全基因组鉴定、多重序列比对、系统进化树构建以及蛋白结构预测对花鲈ncc进行了鉴定及序列分析,利用实时荧光定量PCR (qRT-PCR)检测ncc和nkcc在海水、淡水花鲈鳃组织中的表达水平,利用原位杂交技术确定ncc2和nkcc1a在海水及淡水花鲈鳃中的表达位置。结果显示,从花鲈中鉴定出2个ncc基因,即ncc1和ncc2,其编码序列(CDS)长度分别为2 691和3 120bp,编码896和1 039个氨基酸,在进化上具有保守性。ncc2在淡水花鲈鳃组织中的表达量显著高于海水,而nkcc1a在海水花鲈鳃组织中的表达量显著高于淡水,ncc1、nkcc1b、nkcc2在海淡水中的表达量则无显著差异。淡水适应过程中花鲈鳃组织中的ncc2的表达量逐渐上调,而nkcc1a的表达量逐渐下调;海水适应过程则呈现相反的表达趋势。此外,原位杂交结果显示,ncc2和nkcc1a基因分别位于淡水与海水中鳃组织的相邻鳃小片间的鳃丝上皮。以上结果表明,ncc2和nkcc1a基因分别编码淡水及海水花鲈鳃中重要的Na+及Cl  相似文献   

9.
Water quality in sea-cages, and metazoan ectoparasites on bass, Dicentrarchus labrax (L.), and bream, Sparus aurata L., were sampled at two fish farms in south-west Greece over 2 years. The seabed and marine life around the cages of one farm was surveyed using scuba. The most frequent and abundant parasites were the monogeans Sparicotyle chrysophrii and Furnestinia echeneis on the gills of bream, and Diplectanum aequans on the gills of bass. The copepod Caligus minimus occasionally occurred in the buccal cavity of bass, but only in low numbers. Prevalence and abundance of parasites increased with bass size but F echeneis levels decreased with bream size. There were no other clear relationships between water quality, parasite levels and fish size. Ammonia varied seasonally with sea temperature, and with oxygen levels below 6 mg 1-1 on many occasions, it is possible that fish suffered stress from a combination of high ammonia and low oxygen conditions. There was no accumulation of waste food or faeces below the cages at the one farm surveyed, but there were thousands of wild fish, including mullet (Mugilidae), Spicara sp. and Diplodus spp., present around the cages. Water quality may be improved by changes in farm management, such as reducing stocking densities below the present 16 kg nr-3. Oxygen should be monitored at the cages on site daily. How comparable environmental conditions and impacts, and parasitization are at other bass and bream sea cage farms is unknown.  相似文献   

10.
In 2000–2001, an investigation was performed in two Sicilian mariculture sites (Pachino and Castellammare) to monitor physiological and biochemical parameters in sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) specimens farmed in off-shore sea cages. Plasma cortisol and glucose levels, tissue lactate concentration, haematocrit and haemoglobin content, lysozyme, haemolytic and haemagglutinating activities were determined. During the experiment, an increase in tissue lactate and plasma cortisol levels and a reduction in haemolytic and haemagglutinating titers, were recorded. Changes occurring in these haematological, immunological and biochemical values suggest that these parameters can be useful indicators in assessing the condition of chronic stress induced by mariculture operations.  相似文献   

11.
《水生生物资源》1999,12(1):23-30
The common dentex (Dentex dentex) is a sparid fish which is considered a suitable candidate for Mediterranean aqua-culture. A seven-weeks feeding trial was conducted over the summer period with common dentex, sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax). All three species were fed to visual satiety with two practical diets with varying crude protein and crude fat levels (55 % protein, 9 % lipids; 46 % protein, 17 % lipids). The initial body weights were 8.2, 11.6 and 17.3 g for common dentex, sea bass and sea bream, respectively. In all cases, specific growth rates were not significantly affected by dietary treatment, but they varied among species (sea bass 1.7–1.8 %; sea bream 2.1–2.3 %; common dentex 3.1–3.2 %). When comparisons between fish species were made, we observed that the increase in growth rates was linked to a decrease of the whole body fat content, as a consequence of a greater utilisation of dietary lipids as energy substrates. Furthermore, in common dentex, the 17 % lipid diet was able to improve protein retention, but this diet effect was less significant in sea bream and sea bass. In contrast to sea bream, the 17 % lipid diet did not up-regulate plasma GH levels in common dentex, which provides additional evidence for a more efficient utilisation of dietary lipids.  相似文献   

12.
为明确不同选育群体中间球海胆的遗传多样性和遗传结构,利用SSR-seq技术和15个微卫星位点,对1个家系选育群体(FP)、1个群体选育群体(IP)和1个未经选育的普通养殖群体(CP)的遗传多样性及遗传结构进行了分析。结果显示,15个微卫星位点共检测出112个等位基因,FP、IP、CP 3个群体的平均观测等位基因数(Na)分别为5.077、5.133和6.133个,平均有效等位基因(Ne)分别为2.816、2.873和3.638个,平均观测杂合度(Ho)分别为0.522、0.441和0.501,平均期望杂合度(He)分别为0.595、0.599和0.667,平均多态性信息含量(PIC)分别为0.546、0.543和0.623。家系选育群体(FP) He与Ho的差值(0.073)低于IP (0.158)和CP (0.166),平均固定指数(F)(0.115)低于IP (0.248)和CP (0.246)。3个群体间遗传分化系数(Fst)介...  相似文献   

13.
Meagre (Argirosomus regius) is a relatively new farmed fish species in Croatian mariculture. This study is the first attempt to determine the prevalence of cymothoid isopod parasite Ceratothoa oestroides and its effects on cultured meagre in the Mediterranean area. When analysing growth of meagre at two sites in the central part of the Eastern Adriatic Sea, the greatest difference in total fish length was recorded in March 2016, when fish with parasites were 33% smaller than fish without parasites (24.47 ± 3.29 vs. 16.28 ± 1.01 cm; p < .001). The largest difference in mass was also recorded during sampling in March, when parasitized fish was 74% lighter than the unparasitized fish (171.75 ± 72.96 vs. 44.77 ± 6.57 g; p < .001). The presence of the cymothoid isopod in the buccal cavity was observed, and caused fish deformation throughout the entire duration of the study. Also, female parasites with pulli II in marsupium were found. Based on the determined prevalence and effects on production and health status, monitoring of the interaction between C. oestroides and meagre should be considered in future management plans for cultivation of this promising species for Mediterranean aquaculture.  相似文献   

14.
Gilthead sea bream (Sparus aurata L.) aquaculture has rapidly spread around the Mediterranean Sea. Fish escapes from sea cages are one of the major problems for the industry and also represent a threat to the marine environment. Fishery catches are also influenced by escape events, being mirrored in increased landings of cultured species. However, within the Mediterranean, studies shedding light on the incidence of escaped individuals in fisheries landings are scarce. Firstly, the present study describes a simple scale‐examination methodology to distinguish escaped from wild S. aurata landed by coastal fisheries. Secondarily, the incidence of escapees is assessed within landings of the species in the western Mediterranean. The scale readings revealed a monthly incidence of escapees between 11.2 and 20.8%, representing 6.8% of the total income derived from these landings. Moreover, morphological differences between wild fish captured near and far from fish farms point towards escape events as a source of potential genetic admixture between cultured and wild genotypes. Socio‐economic and ecological implications of escapees are discussed, and a set of management guidelines proposed, to prevent and/or mitigate the negative influences of escaped fish on the ecosystem and traditional users of the coast such as fisheries.  相似文献   

15.
Thousands of Scottish wild fish were screened for pathogens by Marine Scotland Science. A systematic review of published and unpublished data on six key pathogens (Renibacterium salmoninarum, Aeromonas salmonicida, IPNV, ISAV, SAV and VHSV) found in Scottish wild and farmed fish was undertaken. Despite many reported cases in farmed fish, there was a limited number of positive samples from Scottish wild fish, however, there was evidence for interactions between wild and farmed fish. A slightly elevated IPNV prevalence was reported in wild marine fish caught close to Atlantic salmon, Salmo salar L., farms that had undergone clinical IPN. Salmonid alphavirus was isolated from wild marine fish caught near Atlantic salmon farms with a SAV infection history. Isolations of VHSV were made from cleaner wrasse (Labridae) used on Scottish Atlantic salmon farms and VHSV was detected in local wild marine fish. However, these pathogens have been detected in wild marine fish caught remotely from aquaculture sites. These data suggest that despite the large number of samples taken, there is limited evidence for clinical disease in wild fish due to these pathogens (although BKD and furunculosis historically occurred) and they are likely to have had a minimal impact on Scottish wild fish.  相似文献   

16.
This work is aimed at obtaining farmed fish designed to contain targeted PUFAs. To this end, an experiment was conducted with farmed specimens of gilthead sea bream (Sparus aurata L.), which were fed meal containing different percentages of common green bottle fly (Lucilia sericata Meigen) larvae, cultured on appropriate substrates, and then the fatty acid profiles in fish muscles were determined. Results indicate that arachidonic acid content in fish muscle is significantly increased when replacing different proportions of fishmeal by larvae from L. sericata, which contains arachidonic acid up to 10.6% of total fatty acids. Thus, larvae seem to be a suitable vector for introducing target PUFA in fish muscle and it could also contribute to reduce the use of wild fish stocks for fishmeal production.  相似文献   

17.
Viral encephalopathy and retinopathy disease caused by betanodavirus, genus of the family Nodaviridae, affects marine, wild and farmed species including sea bass, one of the most important farmed species in Europe. This work describes a reliable and sensitive indirect ELISA assay to detect betanodavirus in biological samples using a polyclonal antiserum (pAb 283) against the 283/I09 virus strain, the most common red‐spotted grouper nervous necrosis virus (RGNNV) genotype in the Mediterranean area, and a capture‐based ELISA using a monoclonal antibody (mAb 4C3) specific to a common epitope present on the capsid protein. Using adsorbed, purified VERv preparation, the detection limit of indirect ELISA was 2 μg mL?1 (3 × 105 TCID50 per mL), whereas for capture‐based ELISA, the sensitivity for the antigen in solution was 17 μg mL?1 (35 × 105 TCID50 per mL). The capture‐based ELISA was employed to detect VERv in brain homogenates of in vivo infected sea bass and resulted positive in 22 of 32 samples, some of these with a high viral load estimates (about 1.1 × 108 TCID50 per mL). The ELISA system we propose may be helpful in investigations where coupling of viral content in fish tissues with the presence of circulating VERv‐specific IgM is required, or for use in samples where PCR is difficult to perform.  相似文献   

18.
Coagulation profiles for marine fish were determined with the standard global screening assays, the prothrombin time (PT) and activated partial thromboplastin time (APTT) using homologous tissue thromboplastin and phospholipid extracts to investigate species-specificity of brain thromboplastins, and to establish a base-line coagulation profile for marine fish of economical importance for Mediterranean aquaculture (sea bream, Sparus aurata, sea bass, Dicentrarchus labrax, red porgy, Pagrus pagrus, common dentex, Dentex dentex). Sea bass and sea bream displayed the shortest PT (9.0–15.0 s) and APTT (22.1–35.8 s) in comparison to the other species (PT: 24.8–37.2 s, APTT: 39.6–66.4 s). Red porgy displayed the lowest fibrinogen value (1.2–2.3 g l–1), while no differences were found among the other species (2.2–2.8 g l–1). It is concluded that the interaction of the tissue factor and plasma clotting factor is relatively species specific and that the use of homologous brain extracts is preferable for haemostasis study in marine fish.  相似文献   

19.
Mediterranean monk seals Monachus monachus attacked fish on 11 marine fish farms in the Turkish Aegean between 1992 and 2000. There were 40 attacks on fish farms where gilthead sea bream Sparus auratus and European sea bass Dicentrarchus labrax were raised in holding cages. Single seals usually attacked cages at night, regardless of the size of fish in the cages. The seals damaged both holding nets of the cages and fish and, on most occasions, fish escaped as a result of the attacks. With the exception of only one facility, all fish farms attacked by monk seals were concentrated on the large peninsulas including Karaburun and Bodrum Peninsulas, and the number of seal attacks was higher during the winter months. A direct intervention to deter seals such as the use of lights, feeding with pesticide‐injected fish, noise generation, warning and direct shots with rifles and physical exclusion of seals from holding cages by installing antipredator nets were applied to prevent or reduce seal attacks. Our study shows that deterrents such as lights and warning shots were not effective in preventing monk seal attacks. However, both curtain‐ and bag‐type antipredator nets were found to be effective.  相似文献   

20.
2018年4月四川邛崃地区某养殖场大口黑鲈感染致死性结节病,死亡率高达80%。为明确病因,通过常规微生物分离、鉴定,从患病鱼皮肤溃疡灶、鱼鳔腔积液和肝脏组织中分离到同一株优势菌,命名为HSY-NS02。经菌体形态观察、革兰氏染色和抗酸染色镜检、生理生化实验、16S rDNA序列扩增及系统发育分析和特异性PCR扩增,确定该菌为诺卡氏菌。进一步对健康大口黑鲈进行分离菌的人工感染实验以确定其致病性,结果显示,人工感染鱼出现与自然发病相似症状,且从人工感染鱼体中再次分离到相同菌。组织病理学观察显示,皮肤溃疡灶、心脏、肝脏、脾脏、肾脏和鳃发生不同程度的慢性炎性肉芽肿病变,其中脾脏病变最为严重。对菌株HSY-NS02进行药物敏感性实验,结果显示,该菌对庆大霉素、新霉素和制霉菌素3种药物敏感,对其他18种药物耐受,呈多重耐药性。  相似文献   

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