Feb 24 2016

Cage culture of tilapia in Lake Kivu (Rwanda)

This project document has been developed by a group of trainees who participated during 2015 in the “Fish Culture Development – Africa training course” which is annually hosted by the Egyptian International Centre for Agriculture (EICA) in partnership with Japan International Cooperation Agency (JICA). The proposed location of this project is Lake Kive , Rwanda. The project document started with background information on fish consumption in Rwanda and in the chosen location of the project. The consumer preference to tilapia has been also addressed. The selection of cage site, cage design and other elements are all covered with a target production of 40 tons of tilapia/year in two production cycles. The project documents also covers the source of project funding, project costs (fixed and operating) and cash flow. The project document is supported by Tables and diagrams.

This project is one of more group projects which have been supervised by Dr. Abdel Rahman El Gamal.

http://fishconsult.org/wp-content/uploads/2016/02/Cage-culture-of-tilapia-in-Lake-Kivu-Rwanda.pdf

Permanent link to this article: https://fishconsult.org/?p=13174

Feb 22 2016

Display of sharks in Deira fish market, Dubai (United Arab Emirates)

 

Photo credit:: Patricia Martin Cabrera (United Arab Emirates)

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

The inserted picture was taken in Deira fish market, Dubai, United Arab Emirates

Shark display in Dubai fish market (02) Shark display in Dubai fish market (01)

 

 

 

Even though there is some demand for fresh and dried shark meat, shark-fishing is driven by the lucrative trade of dried shark fins which are used to make shark-fin soup in China, Hong Kong and other parts of the Far East.

Dubai has gained significant attention as a link in the global trade in sharks which are caught in several countries in the region and shipped to Dubai for finning as well as for better prices. According to FAO, Dubai is one of the main Middle East exporters of shark fins whereas around 400-500 tons of shark fins were annually exported especially to Hong Kong from 1998 to 2000. Typically, Shark auction occurs every day in the Deira fish market in Dubai. Some reports consider the shark fins caught regionally and exported from the UAE ranks fifth in the world.

In line with the above, it worth mentioning that in the UAE, shark finning and shark hunting between January to April has been banned in 2008. Moreover, UAE law prohibits the fishing of any species listed on the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES) including the whale shark and three species of hammerhead sharks common in UAE water.

While the trade in whole sharks is legal, the on-boat finning of live sharks was banned by the Ministry of Environment and Water in UAE in 2008.

As expected and because of the significant global value of shark-fin trade as annually ranges from at least US$540 million, and possibly as high as US$1.2 billion, fishermen in the region may continue hunting sharks in a violation to the national regulations issued by almost all Middle East countries.

 

 

Permanent link to this article: https://fishconsult.org/?p=13169

Feb 17 2016

Cage culture of spiny lobster in Indonesia

Photo credit: Credit: Kevin Fitzsimmons (USA)

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

Cage culture of spiny lobster in Indonesia

 

 

 

 

The culture of spiny lobster (Palinuridae) in Indonesia has begun in “Lombok” in the early 2000s where the naturally settled “pueruli” are abundant.

The production of spiny lobster to date is based mainly on naturally settled seed (pueruli), which in some areas of Indonesia are abundant and easily caught including Telong Elong/Gili Belik and Ekas Bay.

In 2011, grow-out production was estimated to be 60 tons whereas the primary species farmed was the “scalloped spiny lobster”, Panulirus homarus, followed by “ornate spiny lobster”, Panulirus ornatus (shown in the inserted picture).

Based on the strong market for spiny lobsters and the relative success of lobster culture by smallholder farmers, it is believed that lobster aquaculture will provide a profitable business opportunity to coastal communities where lobster seeds can be found.

The 81,000 km of coastline in Indonesia is homing thousands of sheltered lagoons and bays that are suitable for sea cage culture.

 

Nursing and grow-out:

Captured lobster seeds are quickly moved from the collection traps and placed in nursery cages with approximate dimensions of 2 to 3 m along each side and 2 m deep, consisting of fine mesh. Nursery cages are furnished with seaweed (Gracillaria sp.) which provides shelter for the small lobsters. The nursing of lobster may last for 1-3 months until attaining 5-10 g.

Grow-out cages are stocked with nursed lobsters at an average density of up to 30/m². Cages with a smaller mesh size are used for the initial phase of grow-out.

As lobsters grow, they are periodically harvested and manually graded whereas larger lobsters are stocked in different cages at lower densities depending on target harvest size; typically around 5/m2 at 200 g and 2/m2 at 500 g harvest size.

The harvest size of P. ornatus is usually around 1 kg which achieves the best price especially for export market and for “sashimi”. This typically takes 18-20 months. In Indonesia, where P. homarus is the most commonly farmed species, the desired market size is 100-300 g, which takes about 9 months.

Traditionally, lobster grow-out farmers use low value finfish (trash fish) supplemented by mollusks and crustaceans to feed lobsters. However, it is likely that farmers might use pellet feeding once a reliable supply at affordable price is secured.

Outlook:

As the demand for lobster seeds increases, its price is expected to increase which may cause a constraint for the development of lobster culture as practiced by coastal small holders in Indonesia who primary depends on the availability and pricing of lobster seeds.

For sustainable lobster aquaculture a shift from low-value trash fish to formulated pelleted diets needs to be considered. Similarly, the hatchery technology for seed production of lobster needs to be commercialized.

Permanent link to this article: https://fishconsult.org/?p=13164

Feb 16 2016

California sea lion (Feeding habits – reproduction – conservation) – Video

California sea lion with open mouth

I filmed this video in the Sea World, Saint Diego, California, USA during December 2014.

Source: www.fishconsult.org

Feeding habits: California sea Lions (Zalophus Californianus) are carnivorous having fish being their favorite food including herring, mackerel, pompano, salmon, capelin and squid. They also feed on crabs and clams.

The quantity of fish consumed by sea lions depends on their size as well as the abundance of fish in their habitats. Sea lions may use their sensitive whiskers to locate food. They will generally hunt close to the shore as long as their food is sufficient otherwise they move to deeper water looking for food while they become vulnerable to their predators of Killer Sharks and Whales.

Sea Lion swallow their food without chewing or tear it into chunks using their sharp teeth. They also use their back teeth to break the shells on clams so that they can consume what is inside. Adult California sea lions eat about 5% to 8% of their body weight per day (7-18 kg/animal/day).

During the breeding season, adult males fast for a few weeks when defending their territories for ensuring mating opportunities.

Stones are often found in the stomachs of sea lions. Variety of reasons have been suggested for swallowing stones including ballasting while swimming, stop irritation from intestinal parasites or assisting in digestion.

Breeding and Reproduction: Male Sea Lions are mature at about 6 years of age. However, in most instances they won’t end up mating until they are 9-10 years old of age, after they attain full size and are able to attract and compete for females. The females will begin to mate when they are about 3 years old.

During the mating season, males use their barks to intimidate other male Sea Lions that happen to be in the area. A male of California sea lion with established breeding territory on the beach, breads with around 15 females or even more in one season.

Pups are born on land after a gestation of 11 to 11.5 months; a female generally give birth to one pup each year. On average, newly born pups are about 75 cm and 6 kg. It is interesting to know that the female vocalizes during and immediately after the giving birth while her pup instinctively replies. This helps establish the mother-pup bond. Generally only one pup will be born at a time with occasional twins. Nursing lasts for six to twelve months

The pups immediately start to consume mother’s milk which helps them to grow at a fast rate and also to develop the layers of fatty blubber that pups need to stay warm. Blubbers should be formed so pups can survive upon their first entry to the water accompanying their mother.

In addition to mother’s milk, pups begin eating fish at about two months of age, and then they are ready to move into the waters. When pups know how to swim, they are taught by mothers how to hunt for fish even though they will continue to get their main nutrition from drinking the milk from mother till the end of nursing during which pups are also taught to stay away from predators especially their brownish color during the first six months makes them vulnerable to predation before they acquire the normal color through two molts. During nursing, vocal cues continue to be the most important factor in mother-pup recognition.

Threats to sea lions: The main threats to sea lion populations include:

Natural predators: Common predators of California sea lion are killer whales and large sharks. However, it is believed that mentioned predators do not pose a significant threat to healthy adult sea lions that can easily swim faster than Killer Whales and Sharks. However, young and weak sea lions are easier for these predators to capture. The efficient sensory system enables sea lions to feel their predators as they come close by.

Hunting by humans: thousands of years ago, California sea lions were hunted for subsistence. In the late 1800s they were hunted commercially for their hides. In fact, in 1899 the United States Fish and Game Commission concluded that California sea lions were too numerous, and several thousand were killed intentionally as a means to control their over-abundance.

Although the Killing of sea lions was banned whether generally or in particular locations, fishermen continued to shot sea lions because they believe sea lions consume significant quantities of fish which is seen a real threat to their commercial fishery, particularly salmon.  Fishermen also believe that Sea Lions ruin fish nets and equipment.

Miscellaneous threats: Sea lions are facing various threats such as entangling in nylon fishing nets causing severe injury or drowning. The ingestion of plastic debris can cause obstructions in the digestive tract.

Protection and conservation: At present, there are International Laws to help protect Sea Lions from becoming extinct. The laws also target to help protect their natural environments. Today, it is illegal in many areas to hunt, harm, or kill a Sea Lion. In California, there are limits to where boats can go so that Sea Lions aren’t as likely to be struck by them. According to the U.S. Marine Mammal Protection Act (MMPA) of 1972, it is illegal to hunt or harass any marine mammal in U.S. waters. There are various means to enforce the banning which include rewards which are offered for the reporting of such illegal activities. The penalties for the illegal hunting range from fines to jail time to a combination of both.

 

Permanent link to this article: https://fishconsult.org/?p=13159

Feb 12 2016

Blue-spotted ribbon tail ray, (Biology – utilization – threats)

Photo credit:: Patricia Martin Cabrera (United Arab Emirates)

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

The inserted picture was taken in Sharm El Sheikh (Egypt)

Blue spotted sting ray

Introduction: Blue spotted ribbon tail ray (Taeniura lymma) is a species of stingray in the family Dasyatidae. It is also known as aka blue-spotted fantail rays, blue spotted stingrays, blue spotted rays, and ribbontail stingrays.

Geographical range and habitats: Found in the Indo-West Pacific, the ribbontailed stingray ranges from South East Africa, the Red sea and Arabian Gulf, to the Solomon Islands, north to southern Japan and south to northern Australia.

The species is commonly found around coral reefs in shallow waters, to depths up to 20 meters (rarely found deeper than 30 meters). They are also found foraging near seagrass beds. Unlike most stingrays, ribbontailed stingrays rarely bury themselves in the sand.

Description: The ribbontailed stingray (Taeniura lymma) is recognizable by its striking color pattern with large, bright and neon blue spots on its oval, elongated body (disc) and distinctive blue stripes along either side of the tail. The upper surface of the body disc is grey-brown to yellow, olive-green or reddish brown, while the underside is white. They reach a maximum length about 70-80 cm with a disc diameter of about 30-35 cm across, and up to 5 kg weight. The tail is equipped with one or two sharp venomous spines at the tip, used by the ray to fend off predators.

The snout is rounded and the mouth is found on the underside of the body, along with the gills, adopted for scooping up animals hiding in the sand. The plates which exist within the mouth are used for crushing the shells of crabs, prawns and mollusks.

Feeding habits: Feeding most commonly occurs during the day, but sometimes also at night, where they migrate in groups into shallow sandy areas during the rising tide to excavates sand pits in search of worms, shrimps, crabs, mollusks and small benthic bony fish. Prey is often detected through electroreception, a system which senses the electrical fields produced by the prey.

Reproduction and life cycle: The reproduction of ribbontailed stingray starts by the courtship during which sexually mature males follow female mates, using their acutely sensitive ‘nose’ to detect a chemical signal emitted by females. After mating, and like other stingrays, ribbontailed stingray is ovoviviparous, meaning the embryos are initially sustained by yolk, supplemented by (“uterine milk”, containing mucus, fat, and proteins) produced by the female as the embryo develops. The gestation period is thought to be between four months to a year. A female ribbontailed stingray gives birth to up to seven 13-14 cm across young; each is born with the distinctive blue markings of its parents in miniature.

Utilization: Because of its attractive appearance and relatively small size, the bluespotted ribbontail ray is a popular stingray among marine aquarists despite their poor survival in captivity. The species is utilized as food in East Africa, Southeast Asia, and Australia.

Threats: The ribbontailed stingray is subject to a variety of human-imposed threats as they are commonly taken where heavy artisanal and small-scale commercial fisheries occur in or around coral reef habitats. Their beautiful coloration and high demand for home aquariums led to heavy fishing and in some places more harm occurs when illegal catching methods are used including dynamite fishing and use of cyanide. The widespread destruction of coral reef habitat added significantly to threats imposed on the species. Moreover, with such a low reproductive rate, consisting of long gestation periods and small number of litters, the ribbontailed stingray is particularly vulnerable to population collapses.

 

 

Permanent link to this article: https://fishconsult.org/?p=13150

Feb 04 2016

Fish trade and consumption in Bolivia

Photo credit: Andres Loayza Apaza (Bolivia)

Review: Andres Loayza Apaza and Abdel Rahman El Gamal (Founder of the website)

The inserted picture shows fish display in a fish market in Bolivia. The fish species shown is ”pacu” which is a popular fish for Bolivian consumers. This market is located in the town of Santa Cruz, eastern Bolivia. Fish displayed in the market comes from capture fishery and from aquaculture.

Most of fresh fish whether caught or produced is for human consumption leaving a very small quantity which could be dried for human consumption also while much smaller portion is destined and used in animal feed.

Fish markets in Bolivia are also supplied by imports of fishery products (fresh fish, frozen fish, dry, salted or smoked fish, crustaceans, and molluscs).

Fish consumption in Bolivia being about 1.8 kg/capita/year is considered one of the lowest rates of fish consumption in the world. Realizing the importance of fish in the Bolivian diet an ambitious Agricultural Sector Plan (2014-2018) has proposed an increase in fish consumption from 1.8 to 5.2 kg/person/year by 2018.

 

 

Permanent link to this article: https://fishconsult.org/?p=13146

Feb 04 2016

Fish smoking using barrel oven in Cameroon

Photo credit: Domwa Mathieu (Cameroon)

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

Barrel oven for fish smoking in Cameroon

 

 

 

The inserted picture which was taken in Bambouto (Cameroon) shows a simple fish smoking process using barrel oven made from empty 200-liter oil drums.

The bottom of the barrel is cut out and placed on a sandy or gravel base. An inlet opening for the wood is then carved out of the bottom of the barrel.  Through which, fuel sources are places, fire is let and controlled.

A smoking tray of wire mesh is usually fixed inside the barrel while a grill or wire mesh is placed on the top of the barrel. This will enable exposing fish on the internal tray to intense heat before moving it to the top grill to complete the smoking process in less heat intensity.

The fire is lit and controlled through the bottom openings whereas a wide variety of soft and hard woods, small wood splits, or sawdust is used. The choices are limited by availability, cost and tradition.

The small size of these smokers makes it easy for individual smokers to move around within the smoking area. Similarly, the small volume of such smokers along with the bottom fire makes the control of the smoking process easy especially in regard heat intensity and hence helps avoid burning and/or over-drying of the product. However, the production of very dry smoked product may be intended whenever longer shelf life is targeted.

If this type of smokers is found convenient for small-scale operations which are mostly run by women, these ovens are not appropriate for large-scale commercial ventures.

 

 

 

 

 

Permanent link to this article: https://fishconsult.org/?p=13142

Jan 29 2016

Cage culture of gilthead seabream and European seabass in the region of Leros Island (Greece)

Photo credit: Kyriakos Stamatiou (Greece)

Review: Abdel Rahman El Gamal (Founder of the website)
Marine cages in Greece (02) copy Marine cages in Greece (01) copy

 

 

 

 

Greece is currently the largest producer of European seabass (Dicentrachus labrax) and gilthead seabream (Sparus aurata) in the region producing more than 73,300 and 48600 tons of seabream and seabass respectively in 2013 (FAO). Similarly, Greece is the most developed Mediterranean country in terms of cage aquaculture with more than 300 licensed production sites.  The availability of the coastline with its large number of sheltered sites; as well as the proximity to largest regional market favored the development of marine cages in Greece.

The inserted photos show one of the leading marine cage farm, founded in 1985 and is located on the northern part of the Dodecanese island of Leros in the eastern Aegean Sea. The high quality clear water along with the high average temperature all year round has recommended the island of Leros to be birthplace of Greek aquaculture.

The project shown in the pictures focuses on the production of gilthead seabream, European seabass along with stone bass (argyrosomous regius), sheephead bream (puntazzo puntazzo) and red bream (pargus major).

Juveniles required for the cages are produced in the company’s hatchery in numbers sufficient to produce 3000 metric tons of market size fish every year.

 

 

Permanent link to this article: https://fishconsult.org/?p=13138

Jan 29 2016

Spearfishing in Libya (Video)

Video credit: Abdallah Elmgawshi (Libya)

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

Source: www.fishconsult.org

Spearfishing in Libya

 

 

This video was filmed at Alhabry & Sultan (Libya). The water in this diving spot is clear making it ideal for spearfishing. As shown in the video, spear guns were used. Fish commonly fished in Libyan waters using spearfishing include groupers, sea bream, and garfish.

Permanent link to this article: https://fishconsult.org/?p=13133

Jan 29 2016

Skipjack fishery in the Maldives

Photo credit: Tim Huntington (UK – Poseidon)

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

Skipjack in the Maldives

 

 

 

 

The landing of skipjack (Katsuwonus pelamis) in the Maldives amounts about 20% of the reported total Indian Ocean skipjack catch whereas the catches in the Maldives peaked in 2006 amounting to 138,000 tons, but have been declining afterwards reaching 59,000 tons in 2010.

The majority of skipjack tuna are caught from live pole-and line fishery, while the remaining is caught from the hand line and longline fishery.

Traditionally, the one-day fishing operation used to be adopted. In such case, fishermen do not take ice on boat and they return to port by evening with whatever catch they have. Skilled fishermen are capable to spot the free swimming tuna schools by observing frigatebirds  as they fly high over the ocea.

The inserted picture shows the landing of the skipjack catch. As the fish are temporarily laid loose on the beach, it indicates this quantity is a single day catch.

 

 

Permanent link to this article: https://fishconsult.org/?p=13131

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