I saw an expert Japanese chef fillet a mackerel (Scomber scombrus). He cut off the head and the whole intestinal sac came out with it as a single unit. Then he took the knife and scraped something from inside on the back. The object(s) were dark and bloody. Would those have been the kidneys?

You can see the video here: https://www.youtube.com/watch?v=udTHiRg34KI. The moment is at 2:20.


1 Answer 1


Yes, those are the kidneys. They're quite different from mammalian kidneys.

This is a picture highlighting the kidneys in a salmon dissection from the Pacific Streamkeepers Federation (http://www.pskf.ca/sd/). A very different fish, but similar enough to show the kidneys. Salmon Kidneys

You can also see a dissection of the fish urogenital system here: http://necropsymanual.net/en/teleosts-anatomy/excretory-and-osmo-regulatory-system/, though I can't tell what fish species they're dissecting.

  • $\begingroup$ Are you going to upvote my question considering that you took the time to answer it? $\endgroup$ Apr 11, 2017 at 3:54
  • $\begingroup$ I just did. Sorry, I'm new here-- is that generally expected? $\endgroup$
    – Kara
    Apr 11, 2017 at 11:55
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    $\begingroup$ @Kara welcome to bio.SE! Like any community-driven Q&A site, we hope that you vote frequently so as to acknowledge the efforts of others (or help to downvote bad/wrong answers once you have enough rep). However, you should only vote when and how you want to -- no one should pressure you to do so. It's perfectly acceptable to answer a question that you don't think qualifies for an upvote (or even one that you downvote). See here for more info. $\endgroup$ Apr 11, 2017 at 12:10

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