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Sebastes

Sebastes 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 Sebastes rather than just read about it. In short: Sebastes is a genus of marine ray-finned fish belonging to the subfamily Sebastinae part of the family Scorpaenidae, most of which have the common name of rockfish. A few are called ocean perch, sea perch or redfish instead.

Sebastes — main illustration
Sebastes — illustration

Key takeaways

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

Reference excerpt

Sebastes is a genus of marine ray-finned fish belonging to the subfamily Sebastinae part of the family Scorpaenidae, most of which have the common name of rockfish. A few are called ocean perch, sea perch or redfish instead. They are found in the Atlantic and Pacific Oceans.

Taxonomy Sebastes was first described as a genus in 1829 by the French zoologist Georges Cuvier, the Dutch ichthyologist Pieter Bleeker designated Perca norvegica, which may have been originally described by the Norwegian zoologist Peter Ascanius in 1772, as the type species in 1876. The genus is the type genus of both the tribe Sebastini and the subfamily Sebastinae, although some authorities treat these as the subfamily Sebastinae and the family Sebastidae, separating the Sebastidae as a distinct family from the Scorpaenidae. Other authorities place it in the Perciformes in the suborder Scorpaenoidei. Some authorities subdivide this large genus into subgenera as follows:

The genus name is derived from the Greek Sebastos, an honorific used in ancient Greek for the Roman imperial title of Augustus, an allusion to the old name for S. norvegicus on Ibiza, its type locality, which Cuvier translated as "august" or "venerable". The fossil record of rockfish goes back to the Miocene, with unequivocal whole body fossils and otoliths from California and Japan (although fossil otoliths from Belgium, "Sebastes" weileri, may push the record back as far as the early Oligocene).

Species Sebastes contains 109 recognized extant species in this genus are:

Characteristics Sebastes species have bodies which vary from elongate to deep, and which may be moderately to highly compressed with a comparatively large head. Their eyes vary from large to small. They may have spines on the head or these may be absent, if spines are present, these can be small and weak or robust and there can be up to 8 of them. They lack a spiny horizontal ridge below the eye. The jaws have many small conical teeth and there are teeth on the roof of the mouth. The single dorsal fin is typically strongly incised at the posterior of the spiny portion which contains 12–15 robust, venom-bearing spines and to the rear of these are 9–16 soft rays, The anal fin has 2–4 spines and 6 to 11 soft rays. There is a spine in each of the pelvic fins as well as 5 soft rays and these are placed under the pectoral fins. The pectoral fins are large and may be rounded or pointed in shape with 14–22 soft rays, the longest being the central rays. The caudal fin is straight to slightly concave. The lateral line may have pored or tubed scales. They vary in size from a maximum total length of 13.7 cm (5.4 in) in S. koreanus to 108 cm (43 in) in S. borealis.

Distribution Sebastes rockfish are found in the temperate North and South Pacific and Atlantic Oceans. Rockfish range from the intertidal zone to almost 3,000 m (9,800 ft) deep, usually living benthically on various substrates, often, as the name suggests, around rock outcrops.

Biology Sebastes rockfish may be long-lived, amongst the longest-living fish on earth, with several species known to surpass 100 years of age, and a maximum reported age of 205 years for S. aleutianus.

Ecotoxicology, radioecology Like all carnivores, these fish can bioaccumulate some pollutants or radionuclides such as cesium. Highly radioactive rockfish have been caught in a port near Fukushima city, Japan, not far from the Fukushima Daiichi Nuclear Power Plant, nearly 2 years after the nuclear disaster (ex: 107000 Bq/kg (2013-02-12); 116000 Bq/kg (2013-02-13) and 132000Bq/kg (2013-02-13), respectively 1070, 1160, and 1320 times more than the maximum allowed by Japanese authorities (as updated on April 1, 2012)

Fisheries Sebastes rockfish are important sport and commercial fish, and many species have been overfished. As a result, seasons are tightly controlled in many areas. Sebastes species are sometimes fraudulently substituted for the more expensive northern red snapper (Lutjanus campechanus).

References

Media related to Sebastes at Wikimedia Commons

Illustrations

Sebastes illustration
Sebastes illustration
Sebastes illustration
Sebastes illustration
Sebastes illustration

Worked examples

Example 1 — a first encounter with Sebastes

Start with the simplest possible case. Write down what Sebastes 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 Sebastes 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 Sebastes 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 Sebastes

In research
Sebastes 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 Sebastes 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
Sebastes is common in secondary-school and first-year university syllabi. It links to neighbouring topics Actinopterygii genera, Extant Rupelian first appearances, Game fish, so understanding it makes those chapters shorter.
In everyday life
Look for Sebastes 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 Sebastes in 20 minutes

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

Frequently asked questions

What is Sebastes in simple terms?

Sebastes is a genus of marine ray-finned fish belonging to the subfamily Sebastinae part of the family Scorpaenidae, most of which have the common name of rockfish. A few are called ocean perch, sea perch or redfish instead.

Why does Sebastes 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 Sebastes?

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 Sebastes.

Tags

  • Actinopterygii genera
  • Extant Rupelian first appearances
  • Game fish
  • Negligibly senescent organisms
  • Rupelian genus first appearances
  • Sebastes
  • Sebastini
  • Taxa named by Georges Cuvier

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