Editing Herring (section)

==Life cycle==
[[File:Herring spawn.jpg|thumb|Herring spawn]]

At least one stock of Atlantic herring [[spawn (biology)|spawn]]s in every month of the year. Each spawns at a different time and place (spring, summer, autumn, and winter herrings). [[Greenland]] populations spawn in {{convert|0|-|5|m|ft|0|abbr=off}} of water, while North Sea (bank) herrings spawn at down to {{convert|200|m|ft|abbr=on}} in autumn. Eggs are laid on the sea bed, on rock, stones, gravel, sand or beds of [[algae]].  <!-- "...the fish were darting rapidly about, and those who have opportunity to see the fish spawning in more shallow water ... state that both males and females are in constant motion, rubbing against one another and upon the bottom, apparently by pressure aiding in the discharge of the eggs and milt" (Moore at Cross Island, Maine).

 -->Females may deposit from 20,000 to 40,000 eggs, according to age and size, averaging about 30,000. In sexually mature herring, the genital organs grow before spawning, reaching about one-fifth of its total weight.

The eggs sink to the bottom, where they stick in layers or clumps to gravel, seaweed, or stones, by means of their mucous coating, or to any other objects on which they chance to settle.

If the egg layers are too thick they suffer from oxygen depletion and often die, entangled in a maze of [[mucus]]. They need substantial water microturbulence, generally provided by [[wave action]] or coastal [[ocean currents|current]]s. Survival is highest in crevices and behind solid structures, because predators feast on openly exposed eggs. The individual eggs are {{convert|1|to|1.4|mm|in|frac=64|abbr=on}} in diameter, depending on the size of the parent fish and also on the local race. Incubation time is about 40 days at {{convert|3|C|F}}, 15 days at {{convert|7|C|F}}, or 11 days at {{convert|10|C|F}}. Eggs die at temperatures above {{convert|19|C|F}}.

The larvae are {{convert|5|to|6|mm|in|frac=32|abbr=on}} long at hatching, with a small yolk sac that is absorbed by the time the larvae reach {{convert|10|mm|in|frac=32|abbr=on}}. Only the eyes are well pigmented. The rest of the body is nearly transparent, virtually invisible under water and in natural lighting conditions.

The dorsal fin forms at {{convert|15|to|17|mm|in|frac=32|abbr=on}}, the anal fin at about {{convert|30|mm|in|frac=32|abbr=on}}—the ventral fins are visible and the tail becomes well forked at 30 to  {{convert|35|mm|in|frac=32|abbr=on}}— at about  {{convert|40|mm|in|frac=32|abbr=on}}, the larva begins to look like a herring.

Herring larvae are very slender and can easily be distinguished from all other young fish of their range by the location of the vent, which lies close to the base of the tail; however, distinguishing [[Clupeidae|clupeoids]] one from another in their early stages requires critical examination, especially telling herring from [[sprat]]s.

At one year, they are about {{convert|10|cm|in|0|abbr=on}} long, and they first spawn at three years.

{{multiple image
| align             = center
| direction         = horizontal
| header            = Egg to juvenile
| header_align      = center
| caption_align     = center
| image1            = Clupeaharenguskils2.jpg
| width1            = 225
| alt1              = 
| caption1          = Transparent eggs with the [[yolk]] and eyes visible and one larva hatched
| image2            = Clupealarvamatchkils.jpg
| width2            = 220
| alt2              = 
| caption2          = Freshly hatched larva in a drop of water beside a match to demonstrate how tiny it is: The black eyes and the yolk are visible.
| image3            = Clupeaharenguslarvaeinsitukils.jpg
| width3            = 210
| alt3              = 
| caption3          = Young larva in typical oblique swimming position, with remaining yolk still attached: Another larva at the upper right is in the classical S-shape of the beginning phase of attacking a [[copepod]].
| image4            = Herringjuvenilekils.jpg
| width4            = 267
| alt4              = 
| caption4          = Still transparent juvenile herring, about 38 mm long and 3 months old: Visible are the [[otolith]]s, the gut, the silvery [[swimbladder]], and the heart.
}}

{{clear}}