Characterisation of production, marketing and consumption patterns of farmed tilapia in the Nile Delta of Egypt

AbstractEgypt has one of the world’s largest aquaculture sectors which makes a significant contribution to income, employment creation and food security. However, there are very limited data available on the farmed tilapia value chain. The aim of this study therefore was to characterise production, marketing and consumption patterns of farmed tilapia in the Nile Delta of Egypt. A cross sectional study was conducted to collect data from tilapia producers (100), transporters (32), retailers (100), fish fry shops (20) and households (300) in three case study communities (fish producing, peri-urban and rural community). We conducted structured questionnaire interviews and participatory assessments for producers and consumers. Focus group discussions with mothers were also held to collect data for the availability, sources and consumption patterns of tilapia.Results showed that, more than half of producers were small scale, having a farm size of 10feddan or less (1feddan=4200m2). The main water supply for almost all farms was agricultural drain water, a potential source of contamination with chemical and biological hazards. The main production constraints were reported to be feed prices, water quality and availability, land rent, fuel and energy sources and environmental conditions. The farmed tilapia value chain was short with some value added in the form of marketing fresh and live fish as well as selling tilapia in fried or grilled form. The majority of produced tilapia was transported to retail sale and sold to consumers as fresh, while only a small proportion was processed by cleaning, grilling or frying. A lack of hygiene during transportation and marketing of farmed tilapia was found that could be potential sources for post-harvesting contamination. The availability and frequency of tilapia consumption were higher in the community in the production areas than in other communities. In non-producing areas, tilapia may be available in the market once a week during the village market day. Potential areas for further research in order to improve safety, quality and production of farmed tilapia were identified

Brain and Pituitary Response to Vaccination in Gilthead Seabream (Sparus aurata L.)

Vaccination is a widely used therapeutical strategy in aquaculture, but whether vaccination elicits stress responses in the central neuroendocrine system and enhances the crosstalk between the immune and endocrine systems in the brain or pituitary after vaccination is unclear. To answer this question two experiments using two different vaccine exposure routes, i.e., bath or intraperitoneal (i.p.) injection, were carried out on gilthead seabream (Sparus aurata L.). In the first one, the stress responses of fish subjected to waterborne Vibrio anguillarum bacterin were compared with responses after air exposure or their combination. In the second experiment, fish were subjected to an intraperitoneal injection of Lactococcus garvieae bacterin and we assessed the central stress response and also whether or not a significant immune response was induced in brain and pituitary. In both experiments, blood, brain and pituitary tissues were collected at 1, 6, and 24 h post stress for plasma hormone determination and gene expression analysis, respectively. Results indicated that bath vaccination induced a decreased central stress response compared to air exposure which stimulated both brain and pituitary stress genes. In the second experiment, injection vaccination kept unchanged plasma stress hormones except cortisol that raised at 6 and 24 h. In agreement, non-significant or slight changes on the transcription of stress-related genes were recorded, including the hormone genes of the hypothalamic pituitary interrenal (HPI) axis and other stress markers such as hsp70, hsp90, and mt genes in either brain or pituitary. Significant changes were observed, however, in crhbp and gr. In this second experiment the immune genes il1b, cox2, and lys, showed a strong expression in both brain and pituitary after vaccination, notably il1b which showed more than 10 fold raise. Overall, vaccination procedures, although showing a cortisol response, did not induce other major stress response in brain or pituitary, regardless the administration route. Other than main changes, the alteration of crhbp and gr suggests that these genes could play a relevant role in the feedback regulation of HPI axis after vaccination. In addition, from the results obtained in this work, it is also demonstrated that the immune system maintains a high activity in both brain and pituitary after vaccine injection

Movements of marine fish and decapod crustaceans: Process, theory and application

Many marine species have a multi-phase ontogeny, with each phase usually associated with a spatially and temporally discrete set of movements. For many fish and decapod crustaceans that live inshore, a tri-phasic life cycle is widespread, involving: (1) the movement of planktonic eggs and larvae to nursery areas; (2) a range of routine shelter and foraging movements that maintain a home range; and (3) spawning migrations away from the home range to close the life cycle. Additional complexity is found in migrations that are not for the purpose of spawning and movements that result in a relocation of the home range of an individual that cannot be defined as an ontogenetic shift. Tracking and tagging studies confirm that life cycle movements occur across a wide range of spatial and temporal scales. This dynamic multi-scale complexity presents a significant problem in selecting appropriate scales for studying highly mobile marine animals. We address this problem by first comprehensively reviewing the movement patterns of fish and decapod crustaceans that use inshore areas and present a synthesis of life cycle strategies, together with five categories of movement. We then examine the scale-related limitations of traditional approaches to studies of animal-environment relationships. We demonstrate that studies of marine animals have rarely been undertaken at scales appropriate to the way animals use their environment and argue that future studies must incorporate animal movement into the design of sampling strategies. A major limitation of many studies is that they have focused on: (1) a single scale for animals that respond to their environment at multiple scales or (2) a single habitat type for animals that use multiple habitat types. We develop a hierarchical conceptual framework that deals with the problem of scale and environmental heterogeneity and we offer a new definition of 'habitat' from an organism-based perspective. To demonstrate that the conceptual framework can be applied, we explore the range of tools that are currently available for both measuring animal movement patterns and for mapping and quantifying marine environments at multiple scales. The application of a hierarchical approach, together with the coordinated integration of spatial technologies offers an unprecedented opportunity for researchers to tackle a range of animal-environment questions for highly mobile marine animals. Without scale-explicit information on animal movements many marine conservation and resource management strategies are less likely to achieve their primary objectives

Vibriosis in fish: a clinical, pathological and bacteriological study of the disease in Norwegian fishfarms

The work divides naturally into three sections, the first section dealing with the literature apposite to the study. The literature review starts with the historical discovery of the disease, followed by description of morphology, metabolism, antibiotic sensitivity, serology and toxin production of Vibrio anguillarum. Literature on the normal and experimental pathogenesis of the disease is cited with descriptions of attempts to type Vibrio anguillarum into biotype groups. This section also includes a description of the host range and economic significance of the disease. The second section of the study gives a short description of Norwegian fish farms in general, followed by a description of the methods of collection of pathological material from outbreaks of vibriosis in Norwegian fish farms. This section also gives a description of the isolation procedures, bacteriological tests and histological techniques used in the study, followed by a description of the pathology and treatment of the disease. The fourth chapter of the second section gives the results of the bacteriological examinations carried out on 163 strains of Vibrio anguillarum obtained from outbreaks of vibriosis in Norway. This chapter includes a description of morphology, viability, antibiotic sensitivity, biochemical properties and production of specific proteinases identified by means of the caseinate precipitation inhibition test (CPI-test). The third section of the work consists of a computer analysis study of the bacteriological data obtained in the second section of the work. A review of the literature concerning numerical taxonomy is given, followed by a description of different methods for computation of the material. This includes a description of principal components analysis (PCA) and of numerical taxonomy by means of Single Link Listing (SLL). Finally a description of the results obtained with these two methods is given. The PCA method gave two distinct groupings of the strains and allowed all strains to be included in the two groups. There seemed to be an even geographical distribution of both group*, and none of the groups could account for specific pathological findings. Two strains of Vibrio anguillarum obtained from the American Type Culture Collection fell into one group each and Vibrio metchnlkovi (a human vibrion strain which had been included in the study), was demarcated well outside group I. There seemed to be no specific group distribution of fish species, except in the case of isolates from saithe (Gadus virens) which almost all fell into one computer defined group. Examination of the material by means of SLL gave five acceptable groups at 88.7%, leaving 23 strains ungrouped at this level. Comparative study of the groups defined by PCA and by SLL showed that the SLL defined group I and XI fitted into PCA group II, while SLL groups III, IV and V corresponded to PCA group I. It is therefore concluded that the PCA method provided the most suitable way to classify the material and that the taxonomic determinants allowing best definition of strains in the two PCA groups were citrate utilization together with arabinose, lactose, cellobiose and trehalose fermentation. The two groups defined by the computer for Norwegian isolates of Vibrio anguillarum thus did not correspond to the groups proposed by Nybelin (1935) and Smith (1961) who based their grouping on indole production and mannitol and sucrose fermentation

Expanding the moral circle: farmed fish as objects of moral concern

Until recently fish welfare attracted little attention, but international and national legislation and standards of fish welfare are now emerging and an overview of these developments is presented in this study. Whereas animal welfare legislation is based on public morality, animal ethics does not automatically accept public morality as normative and elaborates arguments regarding the way humans should treat animals (referred to as moral standards). In this study we present the most common animal ethics theories. For most of these, sentience is considered a demarcation line for moral concern: if an animal is sentient, then it should be included in the moral circle, i.e. receive moral consideration in its own right and some basic welfare should be ensured. As for fish, research has revealed that the sensory system of teleosts can detect noxious stimuli, and that some kind of phenomenal consciousness, allowing the fish to feel pain, seems to be present. This raises the ethical question as to how much evidence we need in order to act on such indications of fish sentience. A simple risk analysis shows that the probability that fishes can feel pain is not negligible and that if they do indeed experience pain the consequences in terms of the number of suffering individuals are great. We conclude that farmed fish should be given the benefit of the doubt and we should make efforts that their welfare needs are met as well as possible. Finally, the way forward is briefly discussed: efforts must be made to understand what fish welfare means in practical fish farming. This will involve the development of research and education, greater accountability and transparency, compliance with and control of policies, and quality assurance schemes