Oct 03 2014

Pole method in the culture of mussels

Photo credit: Ahmed Shaheen (Egypt)

Technical review: Abdel Rahman El Gamal (Founder of the website)

This photo was taken in Vietnam.

There are several mussel species in Vietnam especially green mussels (Perna viridis). As in many places in the world, the farming methods for oysters and mussels are well established.

Being an off-bottom method in the culture of mussels, this method is used in relatively deep waters (2-4 m at low tide and 5-8 m at high tide).

The stakes (poles) used in this method could be made of bamboo, coconut fronds or other suitable and available materials while keeping in mind the weather conditions. For example, bamboo stakes could be at risk during the monsoon season in which storm could cause great damage to the culture facilities.

The poles are staked at about ½ meter depth and one meter apart in soft, muddy bottoms. The poles are spaced 1 m apart and arranged in rows with about 3 m distance between rows. It is a good practice to wrap the bottom 30 cm of the exposed portion of poles with smooth plastic to minimize possible predation by starfish and crabs.

Mussels settle on the submerged poles at a rate of 2,000–3,000 seeds per meter. The mussels grow rapidly and fill the poles to several layers thick. During the grow-out season, poles are regularly inspected to monitor growth as well as to eliminate predators like starfish and crabs.

Depending on the availability of natural food, the mussels are harvested 6–10 months after settlement or when animals reach 5–10 cm in length. The selective harvesting could be performed whereas bigger mussels are picked while the small ones left for the next cropping season.

Even though the pole method is a simple and a low-cost method for the culture of mussels, this method leads to siltation which makes bays and estuaries too shallow.

Mussel culture in Vietnam

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11903

Oct 02 2014

Marketing of dried fish in the market of Santa Rosa, Lambayeque (Perù)

Credit: Wilder Rodrìguez Arteaga (Peru)

One of the photos shows dried specimens of three species that are namely guitara (Rhinobatos planiceps), raya (Myliobatis peruvianus), and doncella (Hemanthias signifier). In the right bottom corner, fresh doncella is displayed. The second photo shows only dried guitara.

Dried fish is popular in Peru especially those for some marine fish. There are some favourite dishes made from dried fish including:

Tortilla dry streak: Made with eggs, dry line, china yellow onion and ground pepper, tortilla line is one of the most popular dishes in the north of Peru.

The chinguirito: ceviche is derived from a native of the northern coast of Peru, consisting of shredded beef jerky guitar (Rhinobatos planiceps), sort of a natural bay on the coast of the eastern Pacific in the creek Constant Sechura Bay coast, acebichada marinade with lemon juice (Citrus aurantifolia), hot chili peppers (variety of sp. Capsicum chinense) and red onion. Usually the dish is accompanied with cassava (Manihot esculenta) and trifles (Dolichos lablab).

Dried fish in a fish market in Peru 01 Dried guitara in a fish market in Peru 02

Permanent link to this article: https://fishconsult.org/?p=11897

Sep 29 2014

Popular dish of live octopus (Sannakji) in Korea

Photo credit: Kevin Fitzsimmons (USA)

Review: Abdel Rahman El Gamal (Founder of the website)

The dish of live octopus in which is called Sannakji is quite poplar in Korea. This dish is easy to find at most restaurants that serve raw fish or in fish markets. This unique dish has been placed among the tourism attractions. Sannakji is made of either baby or medium-size octopus.  Some people who witnessed this for the first time may feel comfortable trying it especially when thinking about the bite-sized tentacles of the chopped octopus moving in their mouths. However, adventurous eaters enjoy dipping the pieces of live octopus into one of two common sauces; either sesame oil and salt (gireumsogeumjang), or red chili pepper paste and vinegar (chogochujang). Most reviews on eating live octopus came from Noryangjin Fish Market in Seoul.

Eating live octopus in Korea

 

Permanent link to this article: https://fishconsult.org/?p=11891

Sep 28 2014

Before hatching embryos of flathead mullet (Mugil cephalus) – Video

Video credit: Ahmed Shaheen (Egypt)

Technical review: Abdel Rahman El Gamal (Founder of the website and video channel)

This 1-min video shows embryos of Mugil cephalus prior to hatching. The artificial reproduction of grey mullet has ben attempted and initiated in some Mediterranean countries whereas mullet is an important food fish. The video was filmed in a marine hatchery in Alexandria, Egypt. At 25 C, the incubation period for fertilized eggs till hatching is about 110 hours. The embryo shown in the video may require about 30 hours before hatching.

 

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11888

Sep 27 2014

Research and culture of River catfish, Pangasius hypothalamus in the Philippines

Photo credit: Ahmed Hegazy (Egypt)

Review: Abdel Rahman El Gamal (Founder of the website)

 

River catfish (Pangasius spp.) is a large riverine catfish that is indigenous to the countries within the Mekong River Basin and hence the species is not native to the Philippines. Pangasius is considered an economically important food fish because of its fast growth, versatile feeding habit and hardiness.

The species was introduced as food fish in the Philippines by pet shop owners in 1978 and subsequently in 1981 by the Bureau of Fisheries and Aquatic Resources (BFAR) for experimentation whereas studies on Breeding, risk assessment and culture were conducted in 1985.  However, due to the lack of market as food fish, Pangasius fingerlings that resulted from breeding trials by BFAR were sold as “freshwater hammerhead shark” in the ornamental fish trade.

As the Philippine imports of Pangasius fillets from Vietnam continue to increase, there has been a growing interest to invest in the culture the species for food in the Philippines. Accordingly, BFAR has launched scientific studies on the growth and breeding, risk assessment of this “exotic” species (Pangasius hypothalamus) to determine any possible risk -if any- that could accompany the introduction of the species. In general, it is believed that the species is considered as low risk aquaculture species since it cannot reproduce naturally, and hence fingerlings are produced only in local hatcheries through induced spawning.

These studies conducted by BFAR led to developing technical packages for the culture of Pangasius which could be applied in various farming environments and systems such as ponds, cages, polyculture, integration, ..etc. The inserted photo shows a part of the BFAR facility in which studies on the intensive culture of Pangasius were conducted.

In addition to BFAR, there are other Philippine organisms that are contributing to the promotion of Pangasius culture. These include primarily the Department of Trade and Industry (DTI).

BFAR facility for studies on the culture of Pangasius in Philippines

 

 

Permanent link to this article: https://fishconsult.org/?p=11883

Sep 27 2014

Principles and protocols of fish icing

This 2-slide information bite address the principles of fish icing and how heat is transferred from fish to ice in relation to surrounding temperatures and other factors. The icing efficiency has been addressed and utilized in the icing protocols having in consideration transport, fish and shrimp types along with other key related factors.

http://fishconsult.org/wp-content/uploads/2014/09/Principles-and-protocols-of-fish-icing.pdf

Permanent link to this article: https://fishconsult.org/?p=11879

Sep 26 2014

Crushed ice and ice flakes in cooling fish

This 2-slide bite address a phase of fish post harvest which is cooling. Two forms of this bite were addressed which are namely crushed ice and ice flakes. The physical properties of both types as well as their is covered while focusing more on their cooling efficiency.

http://fishconsult.org/wp-content/uploads/2014/09/Crushed-ice-and-ice-flakes-in-cooling-fish.pdf

Permanent link to this article: https://fishconsult.org/?p=11870

Sep 24 2014

Safety concerns upon the temporary holding of dolphins

Credit for the photo: Huseyn Ek (Akuakare, Turkey)
Review: Abdel Rahman El Gamal (Founder of the website)

It is believed that the sonic echoes of the metal tanks may stress dolphins during their holding in open water. This is based on the ability of dolphins to emit variety of sounds and whistles for different purposes while listening for the return echoes. That is why minimizing echoes has been attempted whether through lining the walls of the pools with sound-absorbing materials or incorporating sound traps.

The inserted photo shows a cage that is designed for the temporary holding of dolphins in open waters which is thought to avoid the risk and/or stress which could occur to dolphins when held in metal pools.

Note: This post addresses a specific technical point with no contradiction so ever with the strong calls of the Animal rights groups against confinement animals including dolphins no matter how good the confinements are.

Dolphin cages (01)

 

 

Permanent link to this article: https://fishconsult.org/?p=11854

Sep 24 2014

A 1000-ton seabass off-shore cage farm in Turkey

Credit: Huseyn Ek (Akuakare, Turkey)

The cage shown in the photo is a unit of a cage farm suited in Black Sea (Turkey). The water depth at this location is about 50 meters. The cage diameter is 30 meters with a volume of approximately 10,000 m3. Fish biomass of each cage is about 110-130 tons. The mentioned farm consists of ten cages and hence the target production is about 1000 tons of European seabass/year. This particular farm has four of those cages at the moment and plan to establish five more cages in two years reaching 10000 tons/year of fish biomass as a total production capacity.

Seabass off-shore cages in Turkey

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11849

Sep 22 2014

Lettuce (Lactuca sativa); a common plant in aquaponic system

Many plants have been successfully tested in aquaponic systems in which fish wastes provide the nutrients which are required by the plants in the system. These plants may include lettuce, pepper, tomatoes, kale, broccoli and others. However, lettuce as a leafy plant is widely used in most aquaponic systems. The advantage of lettuce in such systems is attributed to several factors including their fast growth rate (reach maturity in about 4 weeks), ability to grow well in floating beds, high market demand and their adaptability to the system environment especially in relation to the nitrogen content in the water. Like most leafy plants, lettuce grows well in waters of high nitrogen content. Similarly, lettuce will also grow well with the lower phosphorous and potassium as normally characterize aquaponic systems. In addition, lettuce is considered a hardy plant which can withstand wide range of environmental parameters such as temperatures. Moreover, the short growing season of lettuce cannot be overlooked in regard to the cash flow of the operation. The photos included represent the lettuce in aquaponic projects in Colombia, Egypt, Jordan and USA which could be found individually on this website.

Lettuce in aquaponic (Colombia) Lettuce in aquaponic (Egypt) Lettuce in aquaponic (Jordan) Lettuce in aquaponic (USA)

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11839

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