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Jan 14, 2011 12:50 PM

the "blood line" in blue fish

(From this week's top chef). Tiffany got grief for leaving the blood line in her blue fish. I've never cooked that fish, so was wondering where it is and what it looks like. They seemed to imply that leaving the skin on made it hard for her to remove it. Is it just below the skin? Is it like a vein or more like a layer? I was wondering if it was the dark layer just below the skin. Thanks for satisfying my curiosity!

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  1. Since you obviously watched the show, when Carla prepped her bluefish, she pointed out the bloodline, a reddish line that goes lengthwise down the fish. leaving the skin on would make it almost impossible to remove it. Swordfish has a bloodline as well, as do most fish, that darker, fishier tasting section is what Tiffini should have removed. Since Carla won, obviously they didn't mind the taste of the bluefish, just the bloodline.

    5 Replies
    1. re: kimfair1

      I just rewatched that scene, and as I had remembered, carla talked about the bloodline, but didn't point it out. That was kind of why I asked.

      1. re: DGresh

        Ironically I actually LIKE the darker bit far more than the rest of the fish, to the point that when fish that has it (usaully swordfish or mako) is being served in my house I usally get given all of the dark bits.

        1. re: jumpingmonk

          Oh gosh, me too. It's my favorite part of salmon by far.

          1. re: PegS

            May be not with Bluefish which is very oily and strong with the Blood Line removed.

          2. re: jumpingmonk

            I like the bloodline, too. It's like dark vs. white meat on poultry. When I get sushi some times I specifically request hamachi that includes the bloodline.

      2. Tuna and yellowtail have a big bloodline as well. I can tell you from experience that it is very fishy tasting and best removed either before or after cooking.

        1. The blood line is not unique to bluefish. You will find it in most fish. It's the dark line that often runs down the center between the two fillets and adjacent to the spinal column. If you fillet a fish you will no doubt see a blood line. Some are bigger than others and stronger in taste in some than others.

          5 Replies
          1. re: scubadoo97

            thanks for the visual scubadoo97! Just what I was looking for!

            1. re: scubadoo97

              I think scubadoo misspoke. The blood line is not adjacent to the spine, it's right under the skin, so there are actually two blood lines on a fish, running the length of each fillet. It's mainly an issue with ocean going fish near the top of the food chain such as tuna, swordfish, and blue fish. As others have noted, it's also a matter of taste and how pronounced the blood line is. I haven't cooked blue fish or swordfish in a while, but I do I cut out the blood line. Wild salmon has a substantial blood line as well, but I never remove it. Even if you leave it on it won't ruin the fillet. Just eat around it.

              1. re: Zeldog

                Zeldog is right, there is a bloodline in each filet. It is larger or more pronounced near the thicker part of the filet. As to your question of whether it is a "layer", that could be kind of true as well. I have caught and cleaned a lot of bluefish, and I always skin the filets. If I skin it very thinly, I will often have bits of the same "bloodline" across the filet, as well as the "line" along the middle of the filet. I've always been under the assumption that it is really more of a fat layer just under the skin and a fatty line along the length of the fish. It is certainly stronger tasting, and is even a different texture (raw) the the rest of the flesh. I often remove the line in larger filets.

                1. re: Cheez62

                  thank you both! The discussion on Top Chef makes lots of sense now (why she couldn't leave the skin on *and* remove it)

                2. re: Zeldog

                  I didn't misspeak but obviously there are two areas that you want to remove. The picture I attached shows the major blood line which is adjacent to the spinal column.

                  There is another area under the skin which is just under the lateral line on the side of the fish. This is the blood line you are thinking about. I was under the impression that the dark meat there was more fat than blood.

              2. I've been eating bluefish with the bloodline in it my entire life. Small bluefish are good eating, big ones aren't, blood line or no bloodline

                3 Replies
                1. re: redfish62

                  No one has mentioned that contaminates such as mercury (other heavy metals) and PCPs
                  bio-concentrate in higher concentrations in the dark red "blood line" which runs along the fillet interior to the lateral line. I always remove it in pelagic salt water fish although I do make an exception with wild Atlantic Salmon (but don't know why).

                  1. re: Chefmyron

                    I have heard and read this about toxins concentrating in the bloodline meat. My tendency is to believe it but I just did a pretty long Google search and can only find the assertion in blogs and forums similar to this. I find no authoritative source to verify the theory. Is it true that toxins concentrate in the bloodline or is it an urban legend?. Does anyone know an authoritative source based on science and research?

                  2. re: redfish62

                    I use bluefish for bait. That's about it.

                  3. As you no doubt know, many people won't eat blue-fish--for several reasons (strong oily taste, etc). When I was a stay-at-home mom & entertained a couple of times/mo, I'd sometimes serve blue-fish. My manner of cooking was to eviscerate it (it's impossible to remove all bones), to stuff it w/a tasty stuffing--usually corn-bread but not necessarily; I placed a row of sliced lemon above and below stuffing, and baked it. Leave the skin on. One might season the skin and/or brush it w/oo; however, this isn't necessary. I think that I placed a slice of aluminum foil over the top; but, don't seal it tightly. I do recall that at least some of the time I didn't follow this step. I always left the tail and head on during cooking. The result is delicious, and the bones never seemed to bother anyone if the whole fish was a very large one. I like to serve this dish with roasted acorn squash sliced in half, seeds removed, w/center drizzled w/maple syrup & butter before baking, or a squash or other substantial vegetable (turnip might be good) casserole or potato gratin (Bechamel, no cheese), etc. When deciding on side dishes, recall that the fish has a definite flavor--not too strong if you are certain to purchase a fresh fish that has not previously been frozen.