Wednesday, 11 July 2018

Vorticella & Ellobiopsis sp. parasite


Vorticella, a ciliate protozoan evidenced by a conspicuous ring of hair-like stalks found in clusters but attaching independently to the rostrum and appendages.



It is a bell-shaped or cylindrical organism with a conspicuous ring of cilia (hairlike processes) on the oral end and a contractile unbranched stalk on the aboral end. Vorticellas reproduce by longitudinal fission. 


Ellobiopsis sp. appears as green, elliptical to elongate cylindrical stalks penetrating into the body of the shrimp. This pest can affect motility and breeding, which often leads to secondary bacterial infections evidenced by opacity and whitening of the body of the shrimp and usually leading to mortality. 









Turritopsis nutricula


Immortal jelly fish cells will undergo a process called “transdifferentiation” wherein cells will turn into different kinds of cells i.e. the muscle cells of the immortal jellyfish can turn into egg cells or even sperm cells thus they have transformation power.




They have come up with different physical adaptations depending on their environments. For instance, specimens that live in tropical waters have 8 tentacles while ones from more temperate regions have 24 tentacles.



These jellyfish are quite small and while they do sting, they are not poisonous like the box jellyfish which is also tiny at just 2.5cm long.


Tuesday, 10 July 2018

Taura syndrome


Taura syndrome virus (TSV), a small picorna-like RNA virus that has been classified in the new family Dicistroviridae.


Tissue damage due to TSV infection in L.vannamei



Taura syndrome virus has been officially reported from Burma (Myanmar), China, Indonesia, Thailand and Vietnam.



Rough edges of the cuticular epithelium in the uropods that are suggestive of focal necrosis of the epithelium at the arrow sites.




Friday, 6 July 2018

White Feces Syndrome (WFS)


Acute hepatopancreatic necrosis disease (AHPND) in cultivated shrimps has been an increasing prevalence of vermiform, gregarine-like bodies within the shrimp hepatopancreas (HP) and midgut.


WFS appears in shrimps from approximately 2 months of culture onwards and caused by gregarines. The vermiform bodies formations are consisting of Aggregated Transformed Microvilli (ATM). The ATM have originated by sloughing from epithelial cells of the shrimp hepatopancreatic tubules. They accumulate at the HP-midgut junction before being discharged within feces via the midgut.


Thursday, 5 July 2018

Penaeus monodon


Geographic Range:
Giant tiger prawns are native to the coasts of the Arabian Peninsula and the Pacific and Indian Ocean coasts of Australia, Indonesia, south and southeast Asia, and South Africa. They were accidentally introduced to the United States off the coast of South Carolina in 1988, by an unexpected release from an aquaculture centre.

Habitat:
Young giant tiger prawns are most commonly found in estuaries, lagoons and mangroves; they are very tolerant to a range of salinity levels from 2-30 ppt. Adults move into deeper waters and live on rocky or muddy bottoms, ranging in depth from 0-110 m (most commonly at 20-50 m). These shrimps may bury themselves in the substrate during the day, emerging to feed at night. They live in waters ranging from 28-33°C and are unlikely to survive in waters colder than 13°C.





Physical Description:
Giant tiger prawns have a typical prawn body plan including a head, tail, five pairs of swimming legs (pleopods) and five pairs of walking legs (pereopods), as well as numerous head appendages. A carapace (hard exoskeleton) encloses the cephalothorax. Their heads have a rostrum (an extension of the carapace in front of the eyes) and six to eight dorsal teeth, as well as two to four sigmoidally-shaped ventral teeth. A posterior ridge called the adrostral carina extends from the rostrum to the edge of the epigastric spine, which reaches to the posterior end of the carapace. Their first three pairs of pereopods have claws and they are distinguished from other shrimp species by the lack of an exopod (an external branch) on their fifth pleopodia. The telson at the posterior end of the prawn is unarmed, with no spines.


Giant tiger prawns are identified by distinct black and white stripes on their backs and tails; on their abdomens, these stripes alternate black/yellow or blue/yellow. Base body color varies from green, brown, red, grey, or blue. These prawns are very large, reaching 330 mm or greater in length (largest individual found at 336 mm total length) and are sexually dimorphic, with females are larger than males. At sexual maturity, female carapace lengths range from 47-164 mm and their total lengths from 164-190 mm, while male carapace lengths fall between 37 and 71 mm, with total lengths of up to 134 mm. On average, females weigh 200-320 g and males weigh 100-170 g.

Females have a sperm receptacle (thyelycum) located ventrally on the last thoracic segment. After mating, sperm remain in this receptacle until eggs are released. Females have a pair of internal fused ovaries that extend almost the entire length of their bodies, from the cardiac region of the stomach to the anterior portion of the telson. Males have a copulatory organ (petasma, formed by the longitudinally folded endopods of the first pair of pleopods. The presence of an appendix masculina (an oval flap on the second pleopod) can distinguish males from females. Testes are unpigmented/translucent and are found dorsal to the hepatopancreas under the carapace. The vas deferens is also internal, and arises from the posterior margins of the main axis of the testes. Sperm are released through genital pores on the fifth pereopod.






Tuesday, 10 April 2018

Koi Herpesvirus of the family Herpesviridae

Koi Herpesvirus Disease is a viral disease of common carp Cyprinus carpio, including all its ornamental varieties such as koi, ghost koi etc. The virus is highly contagious and may cause up to 100% mortality. KHV has already caused severe fish losses to ornamental wholesalers, retailers and carp fishery owners and continues to pose a significant threat to anyone dealing with or keeping common carp.

As a notifiable disease there is a legal obligation to report any suspicion of a clinical outbreak of Koi Herpesvirus Disease to the Fish Health Inspectorate (FHI). If the disease is found to be present the FHI will advise on the most appropriate methods of control.

 
Koi Herpes Virus Disease  (FHI)


Viral haemorrhagic septicaemia virus (VHSV)
Viral Haemorrhagic Septicaemia Virus (VHSV) is an important fish virus that has caused several large-scale fish kills in both fresh and saltwater fish in farmed and wild fish. Viral haemorrhagic septicaemia (VHS) is a highly infectious virus disease predominantly affecting rainbow trout (Oncorhynchus mykiss) in aquaculture.

The virus is an enveloped negative-stranded RNA virus belonging to the family Rhabdoviridae and the genus Novirhabdovirus. The virus can be divided into 4 distinct genotypes and 10 subtypes with different geographical occurrence, host range and infectivity patterns. VHSV have been isolated in the tempered Northern hemisphere, e.g. North America, Asia and Europe. The disease occurs endemically in the continental part of Europe, in Turkeyand in part of Finland. Occasionally outbreaks in farmed rainbow trout and turbot have occurred in Scandinavia and the British Isles. The North Sea, Kattegat and the Baltic Seahouses endemically infected populations of wild fish. VHSV have been isolated from more than 82 different fish species.


 Viral Haemorrhagic septicaemia virus (OIE)


Infectious haematopoietic necrosis virus(IHNV)
Infectious haematopoietic necrosis (IHN) is a viral disease affecting most species of salmonid fish. Caused by the rhabdovirus, infectious haematopoietic necrosis virus (IHNV), the principal clinical and economic consequences of IHN occur on farms rearing fry or juvenile rainbow trout in freshwater where acute outbreaks can result in very high mortality. However, both Pacific and Atlantic salmon reared in fresh water or sea water can be severely affected.

Infectious hematopoietic necrosis virus (IHNV), is a negative-sense single-stranded RNA virus that is a member of the familyRhabdoviridaeand the genusNovirhabdovirus,like VHSV. IHNV is present inUSAandCanada, inJapanandKoreaand in the continental part ofEurope.

Both VHS and IHN are listed as non-exotic diseases in the EU and are therefore watched closely by the European Community Reference Laboratory for Fish Diseases, and by National Reference Laboratories.


Monday, 9 April 2018

Salmon

Salmon
Most salmon farms hold more than one-half million fish penned in open net-cages, mostly Atlantic salmon. There are over 100 open net-cage farms growing farmed salmon in sheltered bays along the British Columbia coast.
Waste, chemicals, disease, and parasites from the farms pass through the mesh and pollute the surrounding water and seabed. Especially harmful are the sea lice who attach to wild juvenile salmon on their migration out to sea. Too many sea lice can kill the young wild salmon.
Storms, accidents and predators can tear the nets allowing the farmed fish to escape. Predators like seals and sea lions are often shot. Many marine mammals get entangled in the nets and drown.

King (chinook): The lushest fresh salmon, king is the highest in fat and usually the most expensive, prized for its silken, melting texture, which is almost like smoked salmon.

Kingdom:    Animalia
Phylum:      Chordata
Class: Actinopterygii
Order:         Salmoniformes
Family:       Salmonidae
Genus:        Oncorhynchus
Species:      O. tshawytscha
Binomial name: Oncorhynchus tshawytscha
Ocean

Freshwater


Sockeye (red): With a deep, natural color, sockeye is lower in fat but still high overall, allowing the flavor to better come through. Many salmon lovers, including me, consider this the best salmon-eating experience.

Kingdom:    Animalia
Phylum:      Chordata
Class: Actinopterygii
Order:         Salmoniformes
Family:       Salmonidae
Genus:        Oncorhynchus
Species:      O. nerka
Binomial name: Oncorhynchus nerka

sockeye

Coho (silver): A comer, according to Bill Webber and Thea Thomas, independent Cordovan fishermen. It’s already prized by sport fishermen for its fight, and soon, the Cordovans hope, by diners for its mild but distinctive flavor. The most widely available autumn fresh salmon.

Kingdom:    Animalia
Phylum:      Chordata
Class: Actinopterygii
Order:         Salmoniformes
Family:       Salmonidae
Genus:        Oncorhynchus
Species:      O. kisutch
Binomial name: Oncorhynchus kisutch
Coho Salmon

Pink (humpback): So delicate and pale that Thomas compares it to sole—which she does not mean as a compliment. She recalls a tasting for food writers at which many rated pink the highest. “How could they?” she asks. The likely answer: “A lot of these people had never had salmon in their life.”

Kingdom:    Animalia
Phylum:      Chordata
Class: Actinopterygii
Order:         Salmoniformes
Family:       Salmonidae
Genus:        Oncorhynchus
Species:      O. gorbuscha
Binomial name: Oncorhynchus gorbuscha
Pink Salmon

Chum (dog): Like pink, chum is fished in high numbers and is lower in fat than other varieties; when it spawns in intertidal waters, it doesn’t need to build up energy to swim upstream. Its roe, however, is the most valued of the five varieties, because of its size and flavor. After being strained and separated, the eggs make particularly good ikura— the fat, bright-orange pearls familiar in sushi rolls.

Kingdom:    Animalia
Phylum:      Chordata
Class: Actinopterygii
Order:         Salmoniformes
Family:       Salmonidae
Genus:        Oncorhynchus
Species:      O. keta
Binomial name: Oncorhynchus keta
Chum Salmon