Aquaculture

Viral haemorrhagic septicaemia virus (VHSV) has, in recent decades, been isolated from an increasing number of free-living marine fish species. So far, it has been isolated from at least 48 fish species from the northern hemisphere, including North America, Asia and Europe, and fifteen different species including herring, sprat, cod, Norway pout and flatfish from northern European waters. The high number of VHSV isolations from the Baltic Sea, Kattegat, Skagerrak, the North Sea and waters around Scotland indicate that the virus is endemic in these waters. The VHSV isolates originating from wild marine fish show no to low pathogenicity to rainbow trout and Atlantic salmon, although several are pathogenic for turbot. Marine VHSV isolates are so far serologically indistinguishable from freshwater isolates. Genotyping based on VHSV G- and N-genes reveals four groups indicating the geographical origin of the isolates, with one group representing traditional European freshwater isolates and isolates of north European marine origin, a second group of marine isolates from the Baltic Sea, a third group of isolates from the North Sea, and a group representing North American isolates. Examples of possible transfer of virus from free-living marine fish to farmed fish are discussed, as are measures to prevent introduction of VHSV from the marine environment to aquaculture.

Every sector of the livestock industry, the associated services and the wellbeing of both animals and humans are influenced by animal feeding. The availability of accurate, reliable and reproducible analytical data is imperative for proper feed formulation. Only reliable analysis can lead to the generation of sound scientific data. This document gives a comprehensive account of good laboratory practices, quality assurance procedures and examples of standard operating procedures as used in individual specialist laboratories. The adoption of these practices and procedures will assist laboratories in acquiring the recognition of competence required for certification or accreditation and will also enhance the quality of the data reported by feed analysis laboratories. In addition, ensuring good laboratory practices presented in the document will enhance the safety of the laboratory workers. The document will be useful for laboratory analysts, laboratory managers, research students and t...

The Kenyan aquaculture sector is broadly categorized into freshwater aquaculture and mariculture. Whereas freshwater aquaculture
has recorded significant progress over the last decade, the mariculture sector has yet to be fully exploited. The Kenyan
aquaculture industry has seen slow growth for decades until recently, when the government-funded Economic Stimulus Program
increased fish farming nationwide. Thus far, the program has facilitated the alleviation of poverty, spurred regional development,
and led to increased commercial thinking among Kenyan fish farmers. Indeed, national aquaculture production grew from 1,000
MT/y in 2000 (equivalent to 1% of national fish production) to 12,000 MT/y, representing 7% of the national harvest, in 2010. The
production is projected to hit 20,000 MT/y, representing 10% of total production and valued at USD 22.5 million over the next 5
years. The dominant aquaculture systems in Kenya include earthen and lined ponds, dams, and tanks distributed across the country.
The most commonly farmed fish species are Nile tilapia Oreochromis niloticus, which accounts for about 75% of production,
followed by African catfish Clarias gariepinus, which contributes about 21% of aquaculture production. Other species include
common carp Cyprinus carpio, rainbow trout Oncorhynchus mykiss, koi carp Cyprinus carpio carpio, and goldfish Carassius
auratus. Recently, Kenyan researchers have begun culturing native fish species such as Labeo victorianus and Labeo cylindricus
at the National Aquaculture Research Development and Training Centre in Sagana. Apart from limited knowledge of modern
aquaculture technology, the Kenyan aquaculture sector still suffers from an inadequate supply of certified quality seed fish and
feed, incomprehensive aquaculture policy, and low funding for research. Glaring opportunities in the Kenyan aquaculture industry
include the production of live fish food, e.g., Artemia, daphnia and rotifers, marine fish and shellfish larviculture; seaweed farming;
cage culture; integrated fish farming; culture of indigenous fish species; and investment in the fish feed industry.

This paper presents the design and construction of a smart and sustainable fish farm. The farm is based on the hybrid aquaculture concept that combines the advantages of the recirculation aquaculture system (RAS), the zero-water discharge (ZWD), and smart technology. The system’s smartness consists of using the latest technology, including monitoring and automation, ensuring zero water discharge, good water quality, reduced energy consumption, and high biosecurity. In addition, the system does not use chemicals in the aquaculture process. The paper describes the design of this system, including the hydraulic system, the smart monitoring system, the feeding regime, and the control of the biological parameters. Tests conducted in Tabuk, Saudi Arabia, showed high performance of this system with around 90% survival rate. In addition, observations showed the system’s capacity to maintain the water quality parameters within the optimal water quality ranges, reduce energy consumption, and ...

The Citarum River in West Java is the largest water supplier to the Saguling Dam, which plays a major role in electric power generation for the entire Java Island and is used for the aquaculture of marketed fish. To elucidate the extent of degradation in water quality and its causes in the Upper Citarum watershed, physical, chemical and biological parameters for water samples collected from various sites were analyzed. The results demonstrate large site-to-site variations in water qualities and pollutant loads derived from various human activities such as agriculture, cattle raising and the textile industry. To halt worsening conditions of the Citarum watershed, integrated mitigation efforts should be made, taking biophysical pollution mechanisms and local socioeconomic conditions into account.

This paper proposes using a control function to correct for endogeneity in recreation demand models. The control function approach is contrasted with the method of alternative specific constants (ASCs), which has been cautiously promoted in the literature. As an application, we consider the case of travel cost endogeneity in the demand for Great Lakes recreational fishing. Using data on Michigan anglers, we employ a random utility model of site choice. We show that either ASCs or the control function can correct for travel cost endogeneity, although we find that the model with ASCs produces significantly weaker results. Overall, compared with traditional approaches control functions may offer a more flexible means to eliminate endogeneity in recreation demand models.

In the last years pejerrey culture has been developed in an intensive form using circular tanks. Employing this system is possible to obtain fish of commercial size but the production costs are high making this activity not profitable. An alternative to re-duce costs is to rear pejerrey employing a mix system using cages in natural lagoons and a posterior culture in tanks until commercial size (250g). In a first step, pejerrey fish hatched and reared for 25 days at IIB-INTECH aquaculture facilities were transferred to floating cages of 16 m3 (50 fish/m3) placed at Lacombe Lagoon (Chascomús County). Af-ter 11 months, and only eating natural food, these fish had a total length (TL) of 15 ± 0.19 cm and a weight of (W) 25.27 ± 1.5 g. During this period of time the mean sur-vival was 18 %. Then, 400 fish were transported to the IIB-INTECH and placed in an out-door tank of 20.000 liters with an open water flow system and a salinity of 15 g/L. They were fed twice a day to satiation with ar...

Paphia malabarica is an important clam species, which has formed vast beds in the Kalbadevi estuary (Shirgaon creek) and Kajali estuary (Bhatye creek), Ratnagiri. They are exploited here commercially throughout the year for local as well as external markets due to the heavy demand. This study was undertaken to assess seasonal variations in the quality of the meat of clams by estimating the condition index and percentage edibility. Higher values were recorded during the monsoon (June–August). A rapid decline was observed in the edibility values from November onwards. Higher condition index and percentage edibility were recorded from June to November, indicating the high quality of clam meat.

ObjectiveDespite widespread concern over exploitation of the European Union's fish stocks, dietary guidelines in the UK continue to recommend two portions of fish per week. The present study sought to investigate whether health and/or sustainability are motivating factors when purchasing and consuming fish and whether there are sociodemographic trends.DesignA structured, self-completion postal questionnaire exploring consumers’ attitudes towards purchasing fish, their dietary intake, stated purchasing behaviour and sociodemographic information.SettingNottinghamshire, UK.SubjectsAdults from 842 households randomly selected from the electoral register.ResultsOver half of the participants (57·0 %) were aware of the health benefits of fish consumption and reported health as a primary motivator for purchasing fish; however, only 26·8 % actively sought to purchase fish from a sustainable source (e.g. Marine Stewardship Council (MSC) certified fish). Only 30·6 % of participants met cur...

Effects of heavy metals [copper (Cu), zinc (Zn), chromium (Cr), nickel (Ni), manganese (Mn), iron  (Fe), Aluminum (Al), cadmium (Cd), mercury (Hg), stannum (Sn), and lead (Pb)] present in Tubruk harbor (polluted site) comparing to Umm Hufayan lagoon water (control) on liver and kidney performance of Mugil cephalus captured from both sites were investigated. For this purpose, surface water samples of both chosen sites were compared in terms of heavy metals concentrations, pH, and dissolved oxygen. Mullet fish were captured from both sites and blood samples were taken from the fish and sent to the lab for liver and kidney function tests. The results showed that heavy metals levels were significantly higher in Tubruk than those in Umm Hufayan lagoon. Additionally, significantly higher total protein and albumin levels were found in the blood serum of M. cephalus of Umm Hufayan, compared to Tubruk harbor fish samples; however, higher levels of bilirubin (BR), alanine transaminase (ALT), ...

A pen culture system of the mud crab, Scylla serrata was introduced in Mtwapa mangrove creek with the aim of finding an alternative source of income and food for the local communities, who practice artisanal fishery in the creek. Other objectives were to motivate the interaction between scientists and the community through technology transfer, and to collect scientific data necessary for maintenance and management of the culture system. Pen construction took place from October 2000 - January 2001. The pen was located in the intertidal area and measured 800 m2. It was constructed and fenced using uzio (fish trap) material made of mangrove poles and wood. Stocking of the pen with seed crabs occurred from February- May 2001. Local sources was used to obtain a total of 1697 crab seeds which were measured (carapace length and width), weighed and sexed before stocking. The crabs were fed with trash fish obtained from a local fish processing plant. Feeding was conducted once daily, prefera...

Kenya has a great potential for aquaculture growth by producing additional volumes of fish to fill the growing gap in national fish supply, as wild fish catches continue to decline. In order to balance the shortfall between fish production and high increase in demand, the Kenyan government drafted a fiscal policy measure in the form of Economic Stimulus Program (ESP) to stimulate economic growth in the industry. Despite increased aquaculture adoption and subsequent increase in fish supply in the country, little is known about consumer preference of farmed fish products that ultimately may hinder optimization of production and marketing of the aquaculture sub-sector. This study examined factors influencing consumer preferences and marketing trends in the demand for Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) in Kirinyaga and Vihiga Counties in Kenya. A total of 153 questionnaires were administered to 95 and 58 respondents in Kirinyaga and Vihiga coun...

Abstract
Blood cockles Tegillarca granosa culture in natural habitat is one of the way to increase national
production in addition to harvesting natural resources today, but culture in pond is rare to Malaysia.
Many factors need to be considered before the study of blood cockles in the pond is to be carried out. The
presence of plankton as a food source is a key factor in obtaining optimal blood cockles growth. The
study was conducted in two ponds with different treatments. Pond one used commercial probiotic for
water treatment and pond two was as a control. Fertilization was carried out weekly while water
exchange was carried out monthly. Measurement of water quality and chlorophyll a content were
performed once a month. As a result of 12 month of culture, blood cockles from pond one average length
was 22.85+1.80mm and for pond two average length was 25.36+3.00mm. Blood cockles length growth
rate for pond one was 0.66mm/month while for pond two was 0.99mm/month.
Keywords: Tegillarca granosa, growth performance, water quality, blood cockles

The objective of this present study is to determine the optimum concentration for glutathione in the cryopreservation of seurukan fish (Osteochilus vittatus) spermatozoa. A completely randomized design (CRD) was used with 6 treatments and 3 replications. The Seurukan fish sperm was diluted in extender with a ratio of 1:20 (sperm: extender), then glutathione was added at a concentration of 0, 10, 20, 30, 40 and 50 mg L À1. Next, the sperm thawed at 39e40 C for 3 min and mixed with 100 eggs which were randomly selected. The success of the fertilized egg was observed 6 h after fertilization, while the hatching rate was examined 60 h after fertilization. The ANOVA test showed that the addition of glutathione significant affected the sperms motility, fertility and hatching rate of seurukan fish Osteo-chilus vittatus eggs (P < 0.05). By segregation the fresh sperm, a higher sperm motility rate was recorded with an addition of 30 mgL À1 of glutathione (63.00 ± 5.89), however, this value was not significantly different from using concentration of 10 and 20 mg L À1. A higher fertilization rate was produced using glutathione concentration of 50 mg L À1 (51.33 ± 17.01); however, it was also not significantly different from the concentration of 20, 30 and 40 mgL À1. In addition, a higher hatching rate was also recorded using glutathione concentration of 50 mg L À1 (40.33 ± 12.89), this value was not significantly different from using 40 mgL À1 glutathione. Hence, a conclusion was drawn that the optimum concentration of glutathione is 40 mg L À1 of diluent.

In the present investigation, the effect of sub lethal concentration of the garlic aqueous extract on fish Channa punctatus were studied after 24 hrs, 48 hrs, 72 hrs and 96 hrs exposure respectively. Different concentrations of garlic (10 ppm/lit, 15 ppm/lit) used against Protein content of fish and results showed the gradual decrease in the protein content, ranging (106.14 – 91.65 mg/gm) for 10 ppm/lit for (24 hrs – 96 hrs) and (103.90-88.13 mg/gm) for 15 ppm/lit respectively