Milt

Milt is the seminal fluid of fish, mollusks, and certain other water-dwelling animals. They reproduce by spraying this fluid which contains the sperm, onto roe (fish eggs). It can also refer to the sperm sacs or testes that contain the semen.

Milt (sometimes spelled melt^[1]^[2]) or soft roe also refers to the male genitalia of fish when they contain sperm, used as food. Many cultures eat milt, often fried, though not usually as a dish by itself. As a food item, milt is farmed year-round in nitrogen tanks, through hormone induction or photoperiod control.^[3]

Production

Intersex fish are less likely to release milt, or may fail to produce milt at all, due to their sperm ducts being blocked.^[4] Even when intersex fish do produce milt, the sperm density is lower than normal, and the sperm that is present typiclaly has less motility than normal.^[5]

Use in captive breeding

After collection, milt may be refrigerated for brief periods of time to increase sperm motility. Pacu milt, for example, will still have live sperm after 8 hours, and the motility will be higher compared to milt stored at room temperature. ^[6]

Milt as food

Asian cuisine

In Indonesian cuisine, the milt (called telur ikan 'fish egg') of snakehead and snapper is usually made into kari or woku.
In Japanese cuisine, the testes (白子 shirako 'white children') of cod (tara), anglerfish (ankō), salmon (sake), squid (ika) and pufferfish (fugu) are eaten.^[7]
In Korean cuisine, the milt (이리 iri) of Alaska pollock, cod, blackmouth angler, bogeo, and sea bream are eaten.

European cuisine

In Romanian cuisine, the milt of carp and other fresh water fish is called lapți (from the Latin word lactes) and is usually fried.
In Russian cuisine, herring milt (молока, moloka) is pickled the same way as the rest of the fish, but eaten separately, sometimes combined with pickled herring roe. Various whitefish soft roes are usually consumed fried and it is an inexpensive everyday dish.
In Sicilian cuisine, the milt of tuna is called lattume and is used as a typical pasta topping.^[8]
In British cuisine, cod soft roes are a traditional dish, usually fried in butter and spread on toast.
In Czech cuisine, the milt of common carp called mlíčí (from the Czech word mléko - milk) is often used in a fish soup served on Christmas Eve dinner.

Other uses

Milt is highly absorbent of rare earth elements such as neodymium and iron. The heavier the rare earth element, the higher its affinity for milt.^[9] Because of this, it has been proposed as an environmentally-friendly way to recover rare earth elements from waste.^[9]

Chemical composition

Herring milt is 82.5% water, 2% fat, 16.7% protein, and 2% ash for fish with 21% milt. Cod milt is 82% water, 1.1% fat, 14.5% protein, and 1.8% ash.^[10]

Japanese shirako (cod milt) gunkanmaki
Smelt milt
Alaska pollock's liver, roe, and milt

References

^ "Two quick recipes for Melts (aka soft herring roes)". The Fish Society. 4 August 2018. Archived from the original on 30 June 2022. Retrieved 2 August 2023.
^ Dick Lauder, Thomas (1877) [First published 1825]. Lochandhu: A Tale of the Eighteenth Century (Second ed.). Elgin: James Watson. p. 28. Retrieved 2 August 2023 – via Google Books. A mass of herring melts, tinged with the streams of claret, had fallen into his hair, and this, added to his temporary stupor, had led to the Doctor's mistake.
^ "Vegetal Production". Gases in Agro-food processes. 2019. pp. 153–219. doi:10.1016/B978-0-12-812465-9.00013-X. ISBN 978-0-12-812465-9.
^ Harris, Catherine A. (8 October 2010). "The Consequences of Feminization in Breeding Groups of Wild Fish". Environmental Health Perspectives. 119 (3): 306–311.
^ Jobling, Susan (2002). "Wild intersex roach (Rotilus rotilus) have reduced fertility". Biology of Reproduction. 67 (2): 515–524.
^ Spica, L.N. (5 June 2024). "Viability duration of pacu (Piaractus mesopotamicus) milt stored under refrigeration". Brazilian Journal of Biology. 84.
^ Corporation, Zojirushi America (2018-05-11). "An Acquired Taste of Japan – Shirako". Zojirushi Food & Culture Blog. Retrieved 2025-04-27.
^ "What is Milt: Dicovering the Weird Ingredient Made of Tuna Sperm". www.finedininglovers.com. Retrieved 2025-04-27.
^ ^a ^b Takahashi, Yokio (9 December 2014). "Recovery and Separation of Rare Earth Elements Using Salmon Milt". Plos One.
^ Batista, I (2007). "By-catch, underutilized species and underutilized fish parts as food ingredients". Maximising the Value of Marine By-Products. pp. 171–195. doi:10.1533/9781845692087.2.171. ISBN 978-1-84569-013-7.

This biology article is a stub. You can help Wikipedia by expanding it.

[1] "Two quick recipes for Melts (aka soft herring roes)". The Fish Society. 4 August 2018. Archived from the original on 30 June 2022. Retrieved 2 August 2023.

[2] Dick Lauder, Thomas (1877) [First published 1825]. Lochandhu: A Tale of the Eighteenth Century (Second ed.). Elgin: James Watson. p. 28. Retrieved 2 August 2023 – via Google Books. A mass of herring melts, tinged with the streams of claret, had fallen into his hair, and this, added to his temporary stupor, had led to the Doctor's mistake.

[3] "Vegetal Production". Gases in Agro-food processes. 2019. pp. 153–219. doi:10.1016/B978-0-12-812465-9.00013-X. ISBN 978-0-12-812465-9.

[4] Harris, Catherine A. (8 October 2010). "The Consequences of Feminization in Breeding Groups of Wild Fish". Environmental Health Perspectives. 119 (3): 306–311.

[5] Jobling, Susan (2002). "Wild intersex roach (Rotilus rotilus) have reduced fertility". Biology of Reproduction. 67 (2): 515–524.

[6] Spica, L.N. (5 June 2024). "Viability duration of pacu (Piaractus mesopotamicus) milt stored under refrigeration". Brazilian Journal of Biology. 84.

[7] Corporation, Zojirushi America (2018-05-11). "An Acquired Taste of Japan – Shirako". Zojirushi Food & Culture Blog. Retrieved 2025-04-27.

[8] "What is Milt: Dicovering the Weird Ingredient Made of Tuna Sperm". www.finedininglovers.com. Retrieved 2025-04-27.

[:0-9] Takahashi, Yokio (9 December 2014). "Recovery and Separation of Rare Earth Elements Using Salmon Milt". Plos One.

[10] Batista, I (2007). "By-catch, underutilized species and underutilized fish parts as food ingredients". Maximising the Value of Marine By-Products. pp. 171–195. doi:10.1533/9781845692087.2.171. ISBN 978-1-84569-013-7.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]