Nordsøen Oceanarium

Nordsøen (altså havet)

Et lille havområde med mange fisk.

Nordsøen dækker cirka 575.000 km2 og er således kun en dråbe i verdenshavet som breder sig over cirka 362 millioner km2 (72% af jordens overflade)

Der er ikke særligt dybt i Nordsøen, maks. 700 meter i Norske Rende, hvilket er lavt i forhold til de store oceaner, hvor dybden kan være op til 11 kilometer. (gennemsnitlig 3.5 km dybt)

Der fanges årligt 2 millioner tons fisk i Nordsøen (ud af 100 millioner på verdensplan) - altså Nordsøen som udgør 0,16% af havet leverer 2% af fiskene.

Det rige fiskeliv skyldes tilstedeværelse af planteplankton og dyreplankton.

Fiskearter

I Nordsøen findes cirka 230 fiskearten, hvoraf cirka 50 udnyttes af fiskerne, og kun en halv snes arter er økonomisk vigtige. Her kan nævnes

Konsumfisk

• • Torsk og anden torskefisk (f.eks. kuller og sej)

  • Rødspætter

  • Sild

  • Makrel

Skaldyr

• • Jomfruhummer

  • Dybhavsrejer

  • Blåmusling

Industrifisk

• • Tobis

  • Brisling

  • Blåhvilling

Fiskeredskaber

Garn

Eksempelsvis laks, makrel

Stillestående garn som sættegarn, drivgarn eller bundgarn

Skånsomt fiskeri

Trawl (sandbund)

Tragtformet fiskenet som slæbes gennem vandet som bundtrawl eller flydetrawl (pelagisk trawl).

Den altdominerende fiskeform og supertrawlere har nærmest en fabrik ombord.

Not

Eksempelvis sild og makrel

En snurpenot er et meget stort garn, som placeres rundt om en fiskestime. Noten lukkes for neden ved at trække undertællen sammen. Herefter indsnævres garnet indtil fiskestimen kan pumpes om bord med en speciel pumpe.

Meget store fangster i et enkelt kast.

Snurrevod (sandbund)

Eksempelsvis rødspætter og torsk

Snurrevoddet betegnes også "Danish Seine" Fiskemetoden stammer fra 1848 og tilskrives Limfjordsfiskeren Jens Væver. Snurrevoddet var en videreudvikling af landdragningsvoddet. Se illustration her

Muslingeskraber

Eksempelvis blåmuslinger

En jernramme med net bag.

The North Sea

A small area of sea with a lot of fishes

The North Sea covers approx. 575.000 km2 and is only a drop in the world ocean, which covers around 362 million km2 (72% of the Earth's surface)

The North Sea is only a shallow lake with a maximum depth of 700 metres compared to the great oceans, which reach depths up to 11 kilometres (3,5 km in average)

Here, in The North Sea, almost 2 million tons of fish are caught - 2% of the total world catches - still only covering 0.16% of the globe's total sea area.

The large volumes of fish to be found in the North Sea are due to the significant amounts of plant plankton and zoo-plankton.

Fish species

In the North Sea there are approx. 230 different species of fish og which only approx. 50 are fished commercially, and of these there are only few that are of any economic significance, such as:

For consumption:

• • Cod and other cod family such as Haddock and Saithe

  • Plaice and other flatfish like Halibut

  • Heering

  • Mackerel

Crustaceans

• • Norwegian Lobster

  • Shrimps and Prawns

Protein fish

• • Sand Eel

  • Sprats

  • Blue Whiting

Fishing tools

Gillnet

Gillnetting is a common fishing method used by commercial fishermen of all the oceans and in some freshwater areas. Gill nets are vertical panels of netting normally set in a straight line.

Example: Salmon and Mackerel

Trawl (sandbottom)

Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net that is used for trawling is called a trawl.

It can be used as bottom trawling or floating trawling for pelagic fishes.

The most commonly used tool today.

Purse Seine

Eksample: Heering and Mackerel

A common type of seine is a purse seine, named such because along the bottom are a number of rings. A line (referred to as a purse-line) passes through all the rings, and when pulled, draws the rings close to one another, preventing the fish from "sounding", or swimming down to escape the net.

The purse seine vessels can handle very large catches in one single shot.

Danish Seine

Example: Plaice and Cod

Invented by a danish fisherman in 1848. See illustration here

Musseldredges

An iron frame with a net behind it.