Fly River turtle (Description- biology- threats)- Video

This video was filmed at the Sea World (San Diego, California) during January 2015

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

Fly River turtle

 

 

General: Fly River Turtles (Carettochelys insculpta), are also known, as pitted-shelled turtle and also as “pig-nosed turtle” because of their bulbous fleshy shout with prominently pig-like divided nostrils. This species of turtle is native to freshwater streams, lagoons and rivers of the Northern Territory of Australia, as well as to the island of New Guinea. Fly River turtles prefer freshwater rivers, and billabongs with a soft bottom and a depth of one to three meters with dense forests of broadleaf trees along the shores (for feeding). Fly River turtle can grow to about 70 cm carapace length, and to a weight of over 20 kg up to 30 kg.

Description: The Fly River turtle are characterized by their flipper-shaped forelimbs which ensure that turtles have powerful forward locomotion while the hind limbs, with wide webbed surface along with the flap of skin that goes from the hind limbs to the tail, acts as a steering rudder which speeds their escape from typical predators like crocodiles. Each limb has two claws; the claws on the forelimbs are used for tearing food apart as well as for holding onto the carapace of females. The carapace is typically grey to olive (from above), ending in a fleshy snout with two elongated snout with pig-like nostrils that extends above the water like a snorkel enable the turtle to inhale air without being exposed. Males can be distinguished from females by their longer, heavier and narrower tails with the cloaca midway along while the female cloaca is at the base of the tail.

Food: These turtles are opportunistic omnivores eating a wide variety of plant and animal matter including the fruit and leaves of wild fig, flowers, seeds as well as aquatic insects, snails, molluscs, crustaceans, and fish. They may also consume algae and submerged plants. These turtles are known to congregate under overhanging branches and consume fruits as figs and bush apples which fall from the shoreline trees. Their prominent nose acts as a sense organ which can detect food sources, even in muddy water.

Reproduction: Females of Fly River turtle reach maturity at 18-20 or more years of age whereas for the males it is 14–16 years. Courtship and mating occur in the water, it is believed that the male uses his claws to hold onto the female’s carapace during mating. Afterwards, females leave the water and begin to dig nests on sandy river banks using their hind limbs. The clutch size is between seven and 39 eggs. Laid eggs are white, spherical and brittle shelled.

The incubation takes about 100 days during which the development of nested eggs continues but fully developed embryos do not hatch before the existence of trigging factors during the rainy season whereas nested eggs are flooded with water. Based on research findings, after the yolk is absorbed, hatching can be delayed up to 50 days as they stop developing until the rainy season begins; with the oxygen level greatly reduced hatching is triggered. This explains the phenomenon of synchronized hatching of eggs nested at different times. After the hatchlings reach the water, they do not leave this aquatic habitat except to lay eggs.

Threats: Fly River turtle is primarily threatened by over hunting for its eggs and meat for human consumption and by over collection for the pet trade. However, in countries where its eggs and meat is not consumed, turtles are caught and killed by fishermen who believe that turtles raid the bait intended for catching other species. Habitats degradation and pollution are among the threatening factors to the Fly River turtles.

References: Sea World, Status: IUCN: Vulnerable CITES: Appendix II, Toronto Zoo, National Aquarium

 

Permanent link to this article: https://fishconsult.org/?p=13830

Tree-drying of octopus on Lofanga Island

Source of the photo:  Clifford Gessler, 1937. Dangerous islands

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

Historical Tree-drying of octopus

 

 

 

This black & white picture was taken in “Lofanga Island” during 1930s. This island (1.4 km2) which belongs to Kingdom of Tonga (South Pacific) is a small coastal community with only of 39 households and a resident population of 187 people according to 2008 census. Fish and seafood represent to the people in Lofanga their main protein source and contributes considerably to their energy intake. On average and based on a recent survey, the annual per capita consumption is approximately 65 kg for finfish, 17 kg for edible parts of invertebrates in addition to 21 kg for canned fish.

The absence of electrical power (event in the present) has influenced the day-to-day life on the island, in particular for the fisheries activities. Due to the lack of continuous cooling and freezing capacities on the island, sun-drying of fish products has been found –over centuries- to be the practical method to adapt in order to preserve and extend the shelf life of caught fish and invertebrates. Among the invertebrate catch, only octopus and giant clams are targeted commercially and could be sold in nearby market in its dried form especially people of Lofanga limited their visits to the markets in the main island to about twice a month. This low travel frequency accompanied by the absence of electric power has necessitated the adoption of sun-drying of fishery products. Also, the tree-drying of octopus is based on the forestry nature of the island and hence eliminate the need to establish the classic drying racks and so providing an example of the adoption to the natural resources and economic situation on the island. The dried octopus is popular and enjoy consumer acceptance and usually fetch attractive prices.

It may worth mentioning that Lofanga women are traditionally the major players in the collection, cleaning, drying and marketing of octopus and hence contribute substantially to family consumption of vertebrate as well as complement the household income.

Permanent link to this article: https://fishconsult.org/?p=13826

Adding Azolla to tilapia feed in aquaponics in Egypt

Azolla in tilapia feed in aquaponics in Egypt (01) Azolla in tilapia feed in aquaponics in Egypt (2)

 

 

 

The easiness of Azolla cultivation as well as its richness in key nutrients such as proteins, essential amino acids, vitamins and minerals has encouraged the utilization of Azolla in the feed of livestock and poultry. Moreover, Azolla has also been suggested as food stuff for human consumption.

In regard to aquaculture, and looking at the nutritive value of Azolla as well as its limitation especially its lack of some essential macro- and micronutrients, it would be probably useful to utilize Azolla as a supplement to fish feed as shown in the inserted photos which were taken during the assessment of possible added-value of Azolla in a large-scale aquaponics project in Egypt whereas Azolla grown on the site are harvested and the green plant is mixed and coating the dry commercially-manufactured pellets before providing it to tilapia in grow-out tanks.

 

 

Permanent link to this article: https://fishconsult.org/?p=13823

Adding iron to aquaponics

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

Iron in aquaponics (labeled)

 

 

Iron deficiency is common in aquaponic system and may lead to several adverse effects on the plants which turn pale and yellow as the iron deficiency compromises the plants ability to make chlorophyll. Iron deficiency could be detected through visual inspection. In new plant growth, the iron deficiency becomes evident when the entire leaf shows a yellowing or Chlorosis, however in mature leaves, there is a very noticeable and characteristic when the leaves of most plants start to yellow, while the veins in those leaves remain green.

In order the address iron deficiency problems, adding iron is a typical practice in aquaponics system. Chelated iron is the form used in aquaponics system whereas chelated iron compounds are available in different commercial products such as Fe-EDTA, Fe-DTPA, and Fe-EDDHA.  The effectiveness of different forms of chelated iron is influenced –to a large extent- by water pH. In aquaponics as the pH may go to 8 and above, the Fe-EDDHA has been found effective at a wide range of pH making it the most usable form of chelated iron in aquaponics even though the product is expensive and it turns the water color into red. However, there may be different opinions in regard to the iron forms used in the system based on field experiences, availability of the product along with the cost. Also, the pH of water may favor one compound over others.

Added iron would depend on several factors, including the amount of iron already present in the water whether within the system or the water source as well the uptake of iron by the plants. Also, it is important to note that the water volume in the system includes fish tank, water in the sump and water in the grow beds. A standard dosing of 2 mg of pure iron/liter of water every 3 weeks is the industry standard. The actual quantity of the chelated iron compound added would be based on the percentage of iron in a given compound.

While iron deficiency has its negative effects, the oversaturating of iron in aquaponics poses negative effects as the over-dosing of iron can impede the plants ability to take up nutrients and absorb sugars and may eventually leads to death.

In order to maintain the proper all-time iron concentration in aquaponics and not waiting for the deficiency signs to appear and in the same time avoiding the iron overdosing, test kit for iron could be used. In general, iron level should not be allowed to reach as low as 1.5 mg/l.

 

 

Permanent link to this article: https://fishconsult.org/?p=13809

Fish export from Oman – Video

fish-export-from-the-sultunate-of-oman

 

This video was filmed during a brief visit to the facility of Oman Fisheries Company (Muscat) facility in 2013.  According to FAO, 99,007 tons of fish with amount of about 142.9 million US$ of fish has been exported from Oman in 2013.

The major export destinations for Oman fishery products in general are the Gulf Cooperative Council (GCC) countries, the European Union markets especially for fresh fish whereas frozen fish products is exported to China and other countries in the Far East. Moreover, fishery products are exported to the Middle East countries, USA, and Japan. As expected, the demand for particular fishery products as well as its monetary value would determine the destination of finfish and crustaceans exported from Oman. For example, lobster, jumbo shrimp, and other species like amberjack and a variety of grouper species are mainly exported to the USA.

We have been told that this company processes and handles about 40% of all exported fish (30,000 tons) from Oman. Of particular importance, the establishment processes on the average about 300-400 tons of shrimp and 200 tons of tuna annually.

They key exported fish from this particular fish export establishment -in descending order- are cuttle fish (Sepia pharaonic), Indian mackeral (Restrelliger kanagurta), Arabian sea meagre (Agrirosomus heinni), Trevally (Caranx spp), Red seabream (Cheimerius nufar), Barracuda (Sphyraena sp.), grey mullet (Mugil cephalus), yellow-tail scad (Atule mate), sardine (Sardinella longiceps), and sweetlips (Plectorhinchus spp).

Being an EU approved and HACCP accredited establishment, and in order to apply the standard hygiene, the facility is furnished with blast freezers, chill rooms, flake ice makers (shown in the video), and others.

Permanent link to this article: https://fishconsult.org/?p=13792

Produccion y comercializacion de tilapia Roja en Marino (Colombia)- Production of red tilapia in Colombia- in Spanish

produccion-y-comercializacion-de-tilapia-roja-en-tumaco-marino-colombia

 

This project document has been developed by a group of trainees who participated during 2014 in the “Fish Culture Development– training course” which is annually hosted by the Egyptian International Centre for Agriculture (EICA). This particular project addresses the commercial production of red tilapia in Colombia.

Tilapia consumption and trade in Colombia has been addressed in the introduction of the project document before focusing on the technical and financial components of the project ending by standard economic analysis. The project is supported by Tables and diagrams.

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

Permanent link to this article: https://fishconsult.org/?p=13776

Culture of African arowana (Heterotis niloticus) in Burkina Faso

 

Photo credit: Yaya Drabo (Burkina Faso)

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

culture-african-arowana-in-burkina-faso-01 culture-african-arowana-in-burkina-faso-02

 

 

 

The inserted photos show the fish harvest of a one-hectar pond in a private fish farm located in “Di” village, Province Sourou, Burkina Faso. The women shown in the photos are storekeepers who attended the harvest and to buy the need of their stores out of the harvest. As shown in the photos, the African Arowana (Heterotis niloticus) is the main species of the catch.

Typically, the growing season of African Arowans is about 12 months during which fish can attain a weight of about 4 kg/piece. The feed provided is mainly composed of available food stuff such as corn, appropriate byproducts and others. The fingerlings of the species are collected from freshwater natural resources. In the present, the pond production amounts about 8 tons/ha and it is believed there is enough room for development. In addition to African arowans, tilapia and African catfish are also farmed.

 

 

Permanent link to this article: https://fishconsult.org/?p=13787

Climate change in Zambia

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

cover-climate-change-in-zambia

http://fishconsult.org/wp-content/uploads/2016/12/Climate-change-in-Zambia.pdf

[

Permanent link to this article: https://fishconsult.org/?p=13708

Cage culture of gilthead seabream and European seabass in Algeria

Photo credit: Naim Belakri (Algeria)

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

marine-cages-in-algeria

 

 

The inserted photo shows an offshore cage farm located in Boumerdès Province, Algeria which is located on the Mediterranean Sea at the east of the capita Algeria.

Cage culture for marine fish such as gilthead seabream (Sparus aurata) and European seabass (Dicentrachus labrax) has been promoted according to the National Development of Fishery and Aquaculture Plan for 2003-2007 for which potential sites have been identified.

In this particular farm, the diameter and depth of each cage are 25 m and 12 m respectively. Feed used is imported whereas the average production amounts about 50 tons per cage over about 12-16 months of growth. The fingerlings used in the farm are imported.

 

 

Permanent link to this article: https://fishconsult.org/?p=13779

A study visit in Egypt by Burkina Faso aquaculture and fishery delegates

burkina-faso-delegates

 

This short study visit by Burkina Faso aquaculture and fishery delegates has been hosted by Egyptian Government and implemented by the Egyptian International Centre for Agriculture (EICA). The technical part of the mission started with an introductory presentation on fishery resources in Egypt with special emphasis on aquaculture development. The presentation and subsequent discussion has been delivered and led by Dr. Abdel Rahman El Gamal. The mission spent a day at the World Fish center then another day in Kafr El Sheikh; the leading governorate in aquaculture. The last activity in this mission would be tomorrow (December 22) with a visit to the General Authority for Fish Resources Development (GAFRD). The delegates in the mission are:

Mr. SAWADOGO Philippe, Mrs. BADO/KABORE Julienne, Mr. SAWADOGO Moumouni, Mr. OUEDRAOGO R Hamado, Mr. SYLLA Harouna, Mr. BERE Frédéric, Mr. Da Marcel, Mr. DIANDA Abdoulaye, Mr. ZOMA Anselme, Mr. DRABO Yaya and Mr. NIKYEMA Jean Paul.

The inserted picture shows the delegates as well as Mr. Nasr Darwish (Program coordinator) and Dr. Abdel Rahman El Gamal.

 

 

Permanent link to this article: https://fishconsult.org/?p=13695

Load more