science

Mammals and birds excluder device

Mammals and birds excluder device 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 Mammals and birds excluder device rather than just read about it. In short: A mammals and birds excluder device (MBED), also named cachalotera, is a device added to fishing gear that avoids the killing of marine mammals and seabirds during commercial fishing. This device was designed mainly for the interactions with toothed whales: sperm and killer whales.[1][2][3] Mechanism The mammals and birds excluder device consists in a modification to the traditional Spanish bottom longline used in t…

Key takeaways

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

Reference excerpt

A mammals and birds excluder device (MBED), also named cachalotera, is a device added to fishing gear that avoids the killing of marine mammals and seabirds during commercial fishing. This device was designed mainly for the interactions with toothed whales: sperm and killer whales.[1][2][3]

Mechanism The mammals and birds excluder device consists in a modification to the traditional Spanish bottom longline used in the fishery of Patagonian toothfish (Dissostichus eleginoides). Several configurations are in use depending on the country and fishermen. The first descriptions were issued in Chile and Uruguay, starting the tests in 2006. The main bottom longline is set in a simple way with a main line rigging from which many secondary or branch lines are hanging, of about 12 to 15 m long. On each of these lines, a cone-shaped device or protection net is placed in each secondary line, made by two metallic rings on the edge covered by a mesh net: the upper ring of 20 cm of diameter consisting in encased wire ending in retention rigging; and a lower ring of 100 cm diameter, with a separation distance between both rings of 180 cm. The mesh net composing the device is 7.5 cm, and on the upper ring, it ends in a knot allowing movement through the branch lines. Such branch lines are separated from 55 m to 70 m between them, and may be set in variable styles according to the hauling speed. One set contains 6 hooks, and such sets are prepared on the basis of 4 per box. This device as a whole has less density than the end weights (5 to 10 kg) and consequently, it rises up to the retention when hauling, and the hooks are uncovered when it reaches the bottom. When the longline is hauled back, the cone-shaped device is moved to the lower part of the branch lines, covering the hooks and consequently protecting the catch. The hooks are rigged in a piece divided into two bunches of 6 hooks each, being the main piece of 170 cm long and a diameter of 6 mm, and the two bunches are separated at 50 cm one from the other, the secondary lines (12 per piece) are 30 cm long and made of 4 mm diameter multifilament lines.[4]

History First tests were carried out in 2006 in Chile and Uruguay in the longline fishery of toothfish (D. eleginoides) in the case of Uruguay the main assessment were carried out in the FV Banzare operating in two fishing areas at 40° and 50° latitudes in the southwestern Atlantic from March to May 2007. The development of this fishing gear was monitored by fisheries observers on board in all the cases[5][6][7]

Achievements In all the cases, the incidental capture of birds registered was absolute: no bird was captured when the MBED was used on the fishing gear, no marine bird mortalities were due to gear captures during this study. The MBED works in two aspects:

1) the weight attached gives a superior sinking rate, 2) the mesh sleeve that surrounds the captured piece, avoids the access from mammals and marine birds to the fish or the hooks during the hauling of the gear. While using the MBED, with the weight average of 8.5 kg and approximately 40 meters distance between the next, the overall average sinking rate of the longline gear was 1.03 m/s (Uruguayan tests FV Banzare)[8], this rate is markedly superior to the 0.3 m/s demanded by the CCAMLR Conservation Measure 24-02 (2004).

Worked examples

Example 1 — a first encounter with Mammals and birds excluder device

Start with the simplest possible case. Write down what Mammals and birds excluder device 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 Mammals and birds excluder device 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 Mammals and birds excluder device 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 Mammals and birds excluder device

In research: Mammals and birds excluder device 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 Mammals and birds excluder device 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: Mammals and birds excluder device is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bird conservation, Fishing and the environment, Fishing equipment, so understanding it makes those chapters shorter.
In everyday life: Look for Mammals and birds excluder device 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 Mammals and birds excluder device in 20 minutes

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

Frequently asked questions

What is Mammals and birds excluder device in simple terms?

Why does Mammals and birds excluder device 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 Mammals and birds excluder device?

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 Mammals and birds excluder device.