Vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions
1. The mean reduction of egg diameter from March to April is from 1.45 to 1.39 mm and 1.44 to 1.38 mm for artificially and naturally spawned eggs of Arcto-Norwegian cod, respectively. This means a reduction of volume of about 11%. 2. The neutral buoyancy of cod eggs ranges from 29.5-33.0°/oo salinit...
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ftimr:oai:imr.brage.unit.no:11250/102846 2023-05-15T17:08:16+02:00 Vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions Solemdal, Per Sundby, Svein 1981 application/pdf http://hdl.handle.net/11250/102846 eng eng ICES ICES CM Documents;1981/G:77 This report is not to be quoted without prior consultation with the General Secretary. http://hdl.handle.net/11250/102846 28 s. distribution utbredelse marine eggs marine egg VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 Working paper 1981 ftimr 2021-09-23T20:14:37Z 1. The mean reduction of egg diameter from March to April is from 1.45 to 1.39 mm and 1.44 to 1.38 mm for artificially and naturally spawned eggs of Arcto-Norwegian cod, respectively. This means a reduction of volume of about 11%. 2. The neutral buoyancy of cod eggs ranges from 29.5-33.0°/oo salinity. Eggs of captive fish show a tendency of higher specific gravity. 3. The neutral buoyancy of the cod eggs is not correlated to egg size, but to the weight of the eggshell. 4. Computed ascending velocities in the natural environment of Lofoten range from 0.2 mm s⁻¹ to 1.7 mm s¹ , and show an approximately Gaussian distribution with a mean/ascending speed of 1 mm s¹ 5. Since the spawning of Arcto-Norwegian cod is strictly connected to the thermocline at temperatures of 4-6°C, spawning can occur both pelagically and close to the bottom. 6. Norway pout and other gadoids are also spawning in Lofoten, and occasionally their eggs are found in majority. Their vertical distribution have maxima in deeper water, indicating a higher specific gravity than for cod eggs. 7. During calm wind conditions the concentration of cod eggs increases rapidly towards the sea surface. Large variation in the upper centimeters of the sea is found during such conditionsm Increasing wind rapidly mixes down the eggs in the upper meters. As the wind speed maintains, larger parts of the water column are influenced by the wind mixing. At south-westerly wind of 10 ms⁻1 and at 24 hours duration more than 50% of the eggs are found below 30 m depth. Report Lofoten Institute for Marine Research: Brage IMR Lofoten Norway |
institution |
Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
topic |
distribution utbredelse marine eggs marine egg VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 |
spellingShingle |
distribution utbredelse marine eggs marine egg VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 Solemdal, Per Sundby, Svein Vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions |
topic_facet |
distribution utbredelse marine eggs marine egg VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 |
description |
1. The mean reduction of egg diameter from March to April is from 1.45 to 1.39 mm and 1.44 to 1.38 mm for artificially and naturally spawned eggs of Arcto-Norwegian cod, respectively. This means a reduction of volume of about 11%. 2. The neutral buoyancy of cod eggs ranges from 29.5-33.0°/oo salinity. Eggs of captive fish show a tendency of higher specific gravity. 3. The neutral buoyancy of the cod eggs is not correlated to egg size, but to the weight of the eggshell. 4. Computed ascending velocities in the natural environment of Lofoten range from 0.2 mm s⁻¹ to 1.7 mm s¹ , and show an approximately Gaussian distribution with a mean/ascending speed of 1 mm s¹ 5. Since the spawning of Arcto-Norwegian cod is strictly connected to the thermocline at temperatures of 4-6°C, spawning can occur both pelagically and close to the bottom. 6. Norway pout and other gadoids are also spawning in Lofoten, and occasionally their eggs are found in majority. Their vertical distribution have maxima in deeper water, indicating a higher specific gravity than for cod eggs. 7. During calm wind conditions the concentration of cod eggs increases rapidly towards the sea surface. Large variation in the upper centimeters of the sea is found during such conditionsm Increasing wind rapidly mixes down the eggs in the upper meters. As the wind speed maintains, larger parts of the water column are influenced by the wind mixing. At south-westerly wind of 10 ms⁻1 and at 24 hours duration more than 50% of the eggs are found below 30 m depth. |
format |
Report |
author |
Solemdal, Per Sundby, Svein |
author_facet |
Solemdal, Per Sundby, Svein |
author_sort |
Solemdal, Per |
title |
Vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions |
title_short |
Vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions |
title_full |
Vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions |
title_fullStr |
Vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions |
title_full_unstemmed |
Vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions |
title_sort |
vertical distribution of pelagic fish eggs in relation to species, spawning behaviour and wind conditions |
publisher |
ICES |
publishDate |
1981 |
url |
http://hdl.handle.net/11250/102846 |
geographic |
Lofoten Norway |
geographic_facet |
Lofoten Norway |
genre |
Lofoten |
genre_facet |
Lofoten |
op_source |
28 s. |
op_relation |
ICES CM Documents;1981/G:77 This report is not to be quoted without prior consultation with the General Secretary. http://hdl.handle.net/11250/102846 |
_version_ |
1766063985884397568 |