science

Tangle net

Tangle net 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 Tangle net rather than just read about it. In short: The tangle net, or tooth net, is a type of nylon fishing net similar to a gillnet. Left in the water for no more than two days, and allowing bycatch to be released alive, this net is considered to be less harmful than other nets.

Key takeaways

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

Reference excerpt

The tangle net, or tooth net, is a type of nylon fishing net similar to a gillnet. Left in the water for no more than two days, and allowing bycatch to be released alive, this net is considered to be less harmful than other nets. The tangle net is used in the Philippines by commercial fishermen, as well as by the scientific community. When spent, these nets can be bundled, and left on the sea floor to collect smaller species. These bundles are known locally as lumen lumen nets.

Description and technique The tangle net originated in British Columbia, Canada, as a gear specifically developed for selective fisheries. Tangle nets have smaller mesh sizes than standard gillnets. They are designed to catch fish by their nose or jaw, enabling bycatch to be resuscitated and released unharmed. These nets are made with a very thin light nylon rope, have a small mesh and are strung between two ropes, a top rope with floats, and a bottom rope with weights. Dropped to the bottom of the ocean, located and retrieved through the use of a guide line and buoy, these nets have allowed both fishermen and scientists to reach areas not previously accessible. Tangle nets are generally left on the bottom for no more than a day or two so that the fish and bycatch does not die and spoil.

Use in the Philippines For the last two decades tangle nets have been set in deep water near steep underwater cliffs off many islands in the Philippines by local fishermen in order to supplement their income through catching commercially valuable mollusks. Scientists have used this technique in recent years to explore the deep water marine habitat. The rich species diversity of the Philippine Islands has been explored through the use of tangle nets which are able to obtain specimens from areas not reachable by traditional methods of using trawls and dredges. Through the placement of tangle nets 50 to 100 meters long, at depths from 100 meters to 400 meters, this cryptic marine habitat has been explored and many new and/or rare species of gastropods and crustaceans have been acquired. The success of deep set tangle nets was further exploited when Philippe Bouchet and Danilo Largo launched an expedition in 2004 to explore the Panglao area, known as the 2004 Panglao Marine Biodiversity Project.

Lumen lumen nets When tangle nets are damaged beyond repair they are twisted and wrapped into long bundles, which the Philippine locals call lumen lumen nets. These long, sausage-like bundles are placed on the sea bottom along drop-offs in deep water with strong currents and left for several months at a time, which allows time for veligers to settle and larvae to grow. Lumen lumen nets have yielded many more species of marine animals, including many very small species of micromollusks.

See also Drift net Cast net Seine fishing

References

Illustrations

Worked examples

Example 1 — a first encounter with Tangle net

Start with the simplest possible case. Write down what Tangle net 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 Tangle net 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 Tangle net 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 Tangle net

In research: Tangle net 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 Tangle net 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: Tangle net is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fishing industry, Fishing nets, Fishing techniques and methods, so understanding it makes those chapters shorter.
In everyday life: Look for Tangle net 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 Tangle net in 20 minutes

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

Frequently asked questions

What is Tangle net in simple terms?

Why does Tangle net 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 Tangle net?

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 Tangle net.