biology

Pancreas disease in farmed salmon

Pancreas disease in farmed salmon is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pancreas disease in farmed salmon rather than just read about it. In short: Salmon Pancreas disease (PD or SPD) is caused by a species of Salmonid Alphavirus (SAV) called Salmon pancreas disease virus (SPDV). The virus was first described in 1976 in Scotland and in 1989 in Norway.

Key takeaways

Pancreas disease in farmed salmon belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pancreas disease in farmed salmon to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pancreas disease in farmed salmon from memory before moving on to harder problems.

Reference excerpt

Salmon Pancreas disease (PD or SPD) is caused by a species of Salmonid Alphavirus (SAV) called Salmon pancreas disease virus (SPDV). The virus was first described in 1976 in Scotland and in 1989 in Norway. It affects farmed Atlantic salmon (Salmo salar) caused by Marine SAV2 and SAV3 and has also been identified in Rainbow trout (Oncorhyncus mykiss) in the seawater phase caused by SAV2 where the disease is commonly referred to as Sleeping Disease (SD).

Salmonid Alphavirus Salmonid Alphavirus is an RNA virus. Six genotypes of SAV have been identified (referred to as SAV1, 2, 3, 4, 5 and 6), differentiated by the nucleic acid sequences of certain genes. The strains of SAV causing PD belong to the genotypes SAV1, Marine SAV2 and SAV3.

Diagnosis When the fish is infected, it can cause sudden loss of appetite, lethargy and increased mortality. The general symptoms of this virus infection also include difficulties to maintain a correct position in the water due to muscle damage.

Transmission Cross infection is caused by seawater currents, human activities and lacking measures to prevent risk of transmission between sites. Fallowing procedures have proved successful and prevents the survival of the virus in the environment through the fallowing period, and repeated disease outbreak on the same site is due to introduction of new virus.

Geographical distribution Most research is performed in Ireland, Scotland and Norway but the virus has also been identified in England and Mainland Europe where the SAV2 virus affects rainbow trout.

Economic impact The virus is highly infectious and causes large economic losses in the fish farming industry, particularly in Norway and Scotland. In 2010, the economic loss was estimated to be 0.72 € per kg in Norwegian salmon production due to high mortality rates, reduced growth and the quality of the finished product.

Prevention and treatment A monovalent vaccine against PD was made commercially available in 2007 and a multivalent vaccine, capable of immunising the fish against multiple strains of the SPDV, was introduced in 2015. Vaccination is shown to reduce the risk of the fish being infected and reduces the mortality rates due to PD. In addition, vaccination reduces viral shedding into the environment (virus being released from the cells) from already infected individuals, reducing the risk of contamination of neighbouring fish farms. Commercially available fish feed has also been used in an attempt to improve the fish's immune system, but the efficiency of this has not been documented. In Norway, a combination of vaccination, improve biosecurity measures, depopulation, closure of poorly managed fish farms and geographical separation of sites has proved to reduce PD outbreaks. In addition, regularly updated interactive maps are updated daily allowing all interested parties to monitor and contribute to the current state of PD geographically. Between 2009 and 2011 there were between 75 and 89 outbreaks per year. To prevent spreading the Norwegian coastline was in 2008 divided into two administrative zones separated by a production free zone of 10 nautical miles at the same time a vaccination programme was introduced. However, the effect of this has been questioned since the number of PD outbreaks has not been reduced.

References

Worked examples

Example 1 — a first encounter with Pancreas disease in farmed salmon

Start with the simplest possible case. Write down what Pancreas disease in farmed salmon claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pancreas disease in farmed salmon before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pancreas disease in farmed salmon ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pancreas disease in farmed salmon

In research: Pancreas disease in farmed salmon appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pancreas disease in farmed salmon in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pancreas disease in farmed salmon is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alphaviruses, Animal viral diseases, Fish diseases, so understanding it makes those chapters shorter.
In everyday life: Look for Pancreas disease in farmed salmon outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Pancreas disease in farmed salmon” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Pancreas disease in farmed salmon in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pancreas disease in farmed salmon means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pancreas disease in farmed salmon out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pancreas disease in farmed salmon in simple terms?

Why does Pancreas disease in farmed salmon matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pancreas disease in farmed salmon?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pancreas disease in farmed salmon.