science

Predatory fish

Predatory fish is a science 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 Predatory fish rather than just read about it. In short: Predatory fish are hypercarnivorous fish that actively prey upon other fish or aquatic animals, with examples including shark, billfish, barracuda, alligator gar, tuna, dolphinfish, walleye, perch and salmon. Some omnivorous fish, such as the red-bellied piranha, can occasionally also be predatory, although they are not strictly regarded as obligately predatory fish.

Key takeaways

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

Reference excerpt

Predatory fish are hypercarnivorous fish that actively prey upon other fish or aquatic animals, with examples including shark, billfish, barracuda, alligator gar, tuna, dolphinfish, walleye, perch and salmon. Some omnivorous fish, such as the red-bellied piranha, can occasionally also be predatory, although they are not strictly regarded as obligately predatory fish. Populations of large predatory fish in the global oceans were estimated to be about 10% of their pre-industrial levels by 2003, and they are most at risk of extinction; there was a disproportionate level of large predatory fish extinctions during the Cretaceous–Paleogene extinction event 66 million years ago. Creation of marine reserves has been found to restore populations of large predatory fish such as the Serranidae — groupers and sea bass. Predatory fish switch between types of prey in response to variations in their abundance. Such changes in preference are disproportionate and are selected for as evolutionarily efficient. Predatory fish may become a pest if they are introduced into an ecosystem in which they become a new top predator. An example, which has caused much trouble in Maryland and Florida, is the snakehead fish. Predatory fish such as sharks, billfish, alligator gar and tuna form a part of the human diet and are targeted by fisheries, but they tend to concentrate significant quantities of mercury in their bodies because they are high in the food chain, especially as apex predators, due to biomagnification. Predators are an important factor to consider in managing fisheries, and methods for doing so are available and used in some places. Additionally, the existence of these predators also allows its prey to evolve countermeasures through natural selection. Consequently, the predators and prey will be locked in an evolutionary arms race, each looking to gain the upper hand on the other. The presence of fish predators play a large role in the size, shape and swimming performance of the Lithobates clamitans tadpoles. The presence of these predators in their habitat causes the tadpoles to develop small bodies and large tail muscles in order to escape from their predators quicker and more efficiently. Some predatory fish, such as lamnid sharks, billfishes, tuna, opah and butterfly kingfish, have the ability for cranial endothermy, i.e., the ability to elevate eye and brain temperatures, which helps with vision and neural function during ambient temperature changes.

See also Feeding frenzy Scale eating Shark attack Shark feeding

References

External links Predatory fish on AquaticCommunity.com Predator fish in oceans on alarming decline, experts say Washington Post, 21 February 2011.

Illustrations

Worked examples

Example 1 — a first encounter with Predatory fish

Start with the simplest possible case. Write down what Predatory fish claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Predatory fish 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 Predatory fish 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 Predatory fish

In research: Predatory fish appears in science 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 Predatory fish 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: Predatory fish is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ichthyology, Predatory animals, so understanding it makes those chapters shorter.
In everyday life: Look for Predatory fish 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.

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How to study Predatory fish in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Predatory fish 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 Predatory fish out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Predatory fish in simple terms?

Why does Predatory fish matter?

Because it connects several science 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 Predatory fish?

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 Predatory fish.