Jun 27 2014

Training on soap-making from seaweed in Tanzania

Credit: Fadhili Ruzika (Tanzania)

The photos show representatives of seaweed farmers from the entire coast of Tanzania who are attending training sessions on soap making from seaweed. The training has been done in Bagamoyo District Coastal Region. The soap making from seaweed is a value added process which generates higher revenue compared to selling raw seaweed.

Tanzania - soap making from seaweed (01) Tanzania - soap making from seaweed (02) Tanzania - soap making from seaweed (03)

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11067

Jun 25 2014

Pharaoh Cuttlefish, Sepia pharaonis (Distribution – biology – utilization – threats)

Photo credit: Sharmala Naidoo (South Africa) 

Review: Abdel Rahman El Gamal (Website founder)

Introduction: Cuttlefish are sea molluscs that belong to the order Sepiida and to the Cephalopoda class. The photo that shows a specimen of “Pharaoh Cuttlefish” was taken at Sahar landing site, the Sultanate of Oman. The pharaoh cuttlefish (Sepia pharaonis) is a large cuttlefish species that may exceed 40 cm in mantle length and 5 kg in weight. The average longevity of the species is between 1-2 years. The Pharaoh cuttlefish ranks high among the fish export list from Oman.

Distribution and habitats: Its regional distribution includes Red Sea, Arabian Sea, Oman Sea and is also found in wider geographical areas. The Pharaoh cuttlefish is demersal species and occurs in water depth of 100-130 meter, but during the reproductive season, the species is more abundant in the top 40 meters for mating.

Special biological features:

Reproduction: Spawning times vary depending on habitats. After mating, the female deposits her eggs near the coast, between depths of 5 and 20 m.

Feeding: When hunting at night, the Pharaoh cuttlefish swims up to shallower depths to feed on small mollusks, crabs, shrimps, small fishes, octopuses, worms, and occasionally other cuttlefish. On the other hand, its predators are dolphins, sharks, big fishes, and birds.

Camouflage: The Pharaoh cuttlefish can camouflage to avoid its predators.

Harvesting:  The light attracters are used to catch larger species of cuttlefish at night. Also, the cuttlefishes are caught in large numbers during full moon days and fog season.

Utilization: In the past, the cuttlefish was caught and treated as bycatch with almost no commercial value in most of its distribution region including Oman. During 90’s, the attention paid to the importance of the species for human consumption led to the upgrading the species to a much higher category to become a valuable and target species for artisanal and industrial fisheries in Oman. The contribution of cuttlefish in Oman amounted about 16% of the demersal total catch with significant economic returns in 2011. It is believed that Omani cuttlefish are in high demand due to their thick flesh and bigger sizes. The Sepia pharaonis has been proposed as a promising species for mariculture due to its high spawning success, rapid growth rate, disease resistance and tolerance of crowding and handling.

Threats and conservation: The over fishing of cuttlefish is considered a major threat to their populations especially when done during the spawning season. Also, ocean acidification is a potential threat to all cuttlefish and may negatively affect buoyancy regulation of the species. In regard to conservation measures, governing the cuttlefish catch seems the practical method for the conservation of its stocks.

References: Wikipedia, Oman Fisheries Company, Encyclopedia of Life, IUCN, scientific papers

Pharaoh Cuttlefish

 

 

Permanent link to this article: https://fishconsult.org/?p=11062

Jun 24 2014

Locally produced and imported fingerlings of European seabass in Egypt – Video

The video which was filmed in a commercial marine fish farm in Egypt shows the feeding of the fingerlings of European seabass (Dicentrachus labrax) while nursed in an earthen pond. This particular farm imported the fingerlings of seabass from Tunisia (along with the fingerlings of gilthead seabream). Upon the arrival to the farm, the average size was about 1.8 g increasing to about 3 g/specimen during the day of the visit that was 28 days after the stocking.

It may worth mentioning that the hatchery-produced fingerlings of the European seabass amounted 1.8 million in 2012 in addition to minor quantities which are collected from the nature. The import of seabass fingerlings indicates the gap between the supply and demand for the species.

 

Permanent link to this article: https://fishconsult.org/?p=11057

Jun 23 2014

Spawning tank for the Chinese carps in China

Credit: Khamis killei John (South Sudan)

This photo was taken in a Chinese hatchery. The Spawning tank shown in the photo has a circular shape with a depth of 1.5m and diameter of 12 meters. The water inlet in the wall of the tank is on highest on 1.0m while the outlet in the centre leads to the collection point of eggs. Fish spawned in these tanks are Chinese carps including grass carps, silver carp, bighead carps and others. 

Spawning tank for Chinese carps in China

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11051

Jun 23 2014

Development of cage fish farming in Ghana

Credit: Patrick Appenteng (Ghana)

Cages are the fastest developing and most widely used aquaculture facility in Ghana; with its emergence coming along with different technologies and materials.

The picture shows cages under construction. The sizes are 6m×6m×6m. These are mostly constructed by the farmers themselves or cage construction teams. Usually used materials include galvanized pipes, plastic drums and nets specifically made for such purposes.

However, the inserted picture shows galvanized pipes and plastic drums which is now the main material used as floats in cage construction in Ghana.

Cage fish farming in Ghana

 

 

Permanent link to this article: https://fishconsult.org/?p=11047

Jun 23 2014

Mullet fishery in Lake Bardawil (Egypt)

Credit for two photos: Magd Al-Bawaab (Egypt) Description: Abdel Rahman El Gamal (Website founder)

The fishery of mullet in Lake Bardawil amounted 1087 tons in 2012 and so is considered –by far- the leading finfish species in lake catch. As shown in one of the photos, five boats are involved in mullet fishery and operated by a total of about 15 fishermen. The two 6-meter leading boats carry the fishing gears while the remaining three boats of about 4-5 meters contribute to the fishing activities. Reeds are used in making the fishing gears.

Bardawil lagoon (Mullet fishery) 01 Bardawil lagoon (Mullet fishery) 02 Bardawil lagoon (Mullet fishery) 03

Permanent link to this article: https://fishconsult.org/?p=11044

Jun 22 2014

Ready- to-fish boats in Lake Bardawil (Egypt)

Photo credit: Magd Al-Bawaab (Egypt)

Description: Abdel Rahman El Gamal (Website founder)

The photo shows the fishing boats in Lake Bardawil while ready to go fishing after the closing for about four months every year. The closing of the lake fishery is based on gilthead seabream, Sparus aurata and so is determined annually after the ready-to-spawn broodstock of gilthead seabream ends their spawning run; leaving the lake to spawn in the Mediterranean Sea. Therefore, the closing season ensures that the seabream spawners are not within the reach of the fishing gears of fishermen during the spawning season of the species. In the most recent fishery season, the closing started on 30 December, 2013 and lasted till May 2, 2014.

 

Ready to fish boats in Lake Bardawil

 

 

Permanent link to this article: https://fishconsult.org/?p=11037

Jun 20 2014

Utilizing the reeds in Lake Burullus, Egypt

Photo credit: Magd Al-Bawaab (Egypt)

Review: Abdel Rahman El Gamal (Site founder)

Lake Burullus is a large, elongate, and shallow lake that is located between the two Nile branches forming the delta in Egypt.

The salinity in the lake varies according to the distances from the main water sources of the lake; the salinity increases in zones closer to the sea while low salinity dominates near the outflows of drains and canals that flow into the lake.

In zones of fresh to slightly brackish water, the infestation with reeds and other plants is common.  The heavy weed infestation represents a major problem to fishing activities. A variety of actions are taken to control the spread of aquatic plants and reduce its biomass in the lake. These methods include mechanical methods using weed cutters and biological methods through the stocking of grass carp.

The photo shows a sailboat pulling a mass of reeds which is an initiative done by fishermen –or others- who cut and move specific plants such as reeds (Phragmites australis). These reeds are made into mats which are used in variety of purposes in the nearby community. Of course, this method could be effective if done according to ecological studies that consider fish and nutritional dynamics in the lake.

Utilizing reeds from Lake Burullus

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11031

Jun 18 2014

Water quality management of trout production units in Peru

Credit: Wilder Rodriguez Arteaga (Peru)

The culture of rainbow trout (Oncorhynchus mykiss) in Peru contributes to the national fish production as well as in the export. Trout farming is done at altitude in excess of 3500 m altitude; although the lower altitude of 2000 m may suit their farming better.

The two photos show a part of water quality management in a trout farm in Peru including the daily cleaning of the culture units of the bottom accumulated wastes (feces and feed waste) while the second photo shows checking and recording of water temperature. Always, well trained technicians carry out the measurements of water quality.

Peru - water quality management in rainbow trout (01) Peru - water quality management in rainbow trout (02)

 

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11026

Jun 17 2014

Technology of germ cell transplantation in fish

Photo credit: Samart Detsathit (Thailand) – Description: Samart Detsathit and Abdel Rahman El Gamal

The photos were taken during a training program on the “Germ cell transplantation” that was conducted at Oizumi station, Japan. This technique has been developed by Japanese researchers led by Dr. Goro Yoshizaki at Tokyo University of Marine Science and Technology.

The technology could be briefed in the extraction of the primordial germ cells (called spermatogonia) from “masu salmon” (Oncorhynchus masou) and implant it into the hatchlings of rainbow trout (Oncorhynchus mykiss). Depending on the gender of the receipt fish (rainbow trout), the germ cells develop to either fully functioning sperm or egg cells and hence trout broodstock turn into “surrogate parents” for the masu salmon. When the sperm and eggs of treated rainbow trout are combined in vitro fertilization, salmon hatchlings are produced. One of the photos shows the transplantation process into a trout hatchling which acts as recipient fish; another photo shows the transplantation needle that is prepared from a glass capillary and sharped to optimum size. This advanced technology has potential applications in aquaculture as well as in preserving endangered species.

Germ cell transplantation in trout hatchlings (01) Germ cell transplantation in trout hatchlings (02)

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11020

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