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May 20 2018

Moina as a natural food in aquaculture

Photo credit: Luis Landesman (USA)

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

 

Moina is a genus of crustaceans which belongs to the family “Moinidae”. As young moina is less than 400 µm in size, they can serve as the initial food for most freshwater fish species. Monia has been used as the sole food for fry of many ornamental tropical fish species. In order to enhance its nutritional quality, moina should be enriched with algae and yeast before feeding them to fish.

The culture of moina has been easily practiced using horse manure, chicken manure, cow manure, wheat or rice bran, alfalfa pellets or meal, cotton seed meal, spirulina powder, and others.

Moina are characterized by their significant tolerance to adverse water quality parameters. For example, they are able to survive in oxygen-poor environments whereas the amount of dissolved oxygen could be as low as almost zero. Interestingly, the ability of monia to tolerate such very low level of dissolved oxygen is attributed to their ability of the organism to synthesize hemoglobin that greatly enhances the ability of the organism to cope with such poor oxygen situation. Added to that, monia are resistant to withstand an extreme thermal variation that ranges from as low as 5°C to as low as 31°C and above.

 

 

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Permanent link to this article: http://fishconsult.org/?p=14464

May 18 2018

Shrimp eye-tagging

Photo credit: Andres Delgado (Colombia)

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

The inserted picture shows the eye-tagging of shrimp broodstock. This type of marking was found tolerable by shrimp especially large adult shrimp and is not lost during molting.

Eye tags are commonly used to mark adult marine shrimp in captive broodstock populations in hatcheries and/or in genetic breeding programs. The tag is made of plastic or metal and is numbered for identifying individual shrimp. The tag ring is placed on the eyestalk behind the bulbous of the eye.

 

Permanent link to this article: http://fishconsult.org/?p=14460

May 14 2018

Fish trapping during the early 1900s in Cook Islands – eel trap

Photo credit: New Zealand Museum (A permission has been granted to use this picture on this site)

This conical trap which has been known as “Inak” has a flat bottom and a narrow opening at the top. The trap is woven from the long thin coconut roots or the aerial roots of Freycinetia. The trap base is cross strengthened by two wooden strips. The construction of the trap allows easy removal of trapped fish. Usually, such traps are baited with small fish in order to effectively attract target fish especially eels and other larger fish species.

Such traps may have different shapes and sizes. According to the museum records, this particular trap dates back to 1907 and was made in Cook Islands with overall dimensions of 45 cm height and 69 cm diameter.

 

Permanent link to this article: http://fishconsult.org/?p=14451

May 13 2018

Cage culture of red tilapia in Vietnam – Video

Credit for the video and the caption: DO Xuan Hai (Vietnam)

Review: Abdel Rahman El Gamal (Founder of the video channel)

Tilapia culture in Vietnam usually targeted local markets before being exported to a large number in the USA and the European Union.

Red tilapia (Oreochromis spp.) is mainly cultured in floating cages as practiced in the Mekong Delta are made of wooden frames and nets. As the case with cages elsewhere, the ones shown in the video have the advantages of the relatively low capital investment, low operating costs, and easiness of their management.

Almost all cage farmers live on the site for most of the time. Depending on the farm size, the farmers may hire full-time employees, or use part-time workers.

Based on a recent survey, the average dimensions of a cage is 10 m length × 5 m width × 3.5 m depth.  Each cage is stocked by about 16,000 fingerlings of an average weight of about 4 g ranging from 1 to 10 g. The growing season takes about 5.5 months, allowing the production of two crops/year. Some cage farmers produce their own fingerlings while others depend on external resources. The harvested fish often has an average weight of about 700 g. During that grow-out period, fish are fed on pelleted feed.

In addition to cleaning the cages in-between the production cycles, fingerlings may be treated before stocking using baths of either salt, potassium permanganate (KMnO4), copper sulfate (CuSO4), or iodine.

In linkage with that, resource-poor farms such as the red tilapia cage farms are often at the risk of experiencing disease outbreaks and subsequent losses of production, income, and assets.

https://youtu.be/c_tqJD5vpM8

Permanent link to this article: http://fishconsult.org/?p=14447

May 10 2018

Climate change in Argentina (In Spanish)

A permission has been granted by the report owners to publish this report on this site

 

 

Climate change in Argentina

Permanent link to this article: http://fishconsult.org/?p=14443

May 10 2018

Climate change in Bolivia (In Spanish)

A permission has been granted by the report owners for publishing the report on this site

 

 

 

 

 

 

 

 

 

 

Climate change in Bolivia

Permanent link to this article: http://fishconsult.org/?p=14439

May 10 2018

Climate change in El Salvador (In Spanish)

A permission has been granted from the report owners to publish the report on this site

 

 

 

 

 

 

 

 

 

 

 

Climate change in El Salvador

 

Permanent link to this article: http://fishconsult.org/?p=14437

May 10 2018

Climate change in Chile (In Spanish)

A permission has been granted by the report owner for publishing this report on this site

 

 

 

Climate change in Chile

Permanent link to this article: http://fishconsult.org/?p=14433

May 10 2018

Climate change in Peru (in Spanish)

A permission has been granted by the report owners to publish this report on this site

 

 

 

 

 

 

 

 

 

 

 

 

Climate change in Peru

Permanent link to this article: http://fishconsult.org/?p=14429

May 10 2018

Climate change in Sri Lanka (2017)

A permission from the report owners has been granted for publishing the report on this site.

 

 

 

 

 

 

 

 

 

 

 

Climate Change in Sri Lanka

 

 

 

Permanent link to this article: http://fishconsult.org/?p=14418

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