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How to Produce Dark-Colored Shrimp
Ramon Castillo (email@example.com): A regular buyer of our shrimp has asked us to produce dark-colored shrimp (Penaeus vannamei) because that’s what the Philippine market prefers. I have tried three postlarvae suppliers, but I’m still producing light-colored shrimp. Our cement tanks are painted gray, and our water is very dark, almost like dark coffee. Are P. vannamei dark colored because of the food they eat? Our shrimp rely almost exclusively on dry feeds—no algae or plankton—because we grow them indoors.
Aedrian Ortiz (firstname.lastname@example.org): Hi Ramon, the only thing you need to do is paint the tanks black. Like chameleons, shrimp mimic the color of their surroundings. Don’t expect black shrimp, but you will get darker shrimp. We used to feed our shrimp astaxanthin to produce darker shrimp, but then, by accident, we realized that we could save money by using black liners in our tanks.
Daniel Gruenberg (email@example.com): Yes, I agree with Aedrian. Paint the tanks black. Feeding copepods also helps produce a darker color, and shrimp that feed on copepods turn a darker red when they’re cooked.
Ramon Castillo (firstname.lastname@example.org): Hello Aedrian and Daniel, many thanks for the reply. I will paint my tanks black. Actually my customer has been telling me to do that, but I was not convinced that it would work. Once our second greenhouse is up and running, I’ll shut down the first greenhouse and paint its tanks black.
Nelson Gerundo (email@example.com): Ramon, I agree with Aedrian and Daniel. Paint your tanks black. In 2009, the journal Aquaculture carried a study titled Effect of Background Colour on the Distribution of Astaxanthin in Black Tiger Prawn (Penaeus monodon): Effective Method for Improvement of Cooked Colour by R.K. Tume, A.L. Sikes, S. Tabrett and D.M. Smith. You can check it out at the following link: http://www.apfa.com.au/wp-content/uploads/2010/03/prawn-colour.pdf [Editor, If this link does not work, cut and paste it into your web browser's address bar and hit return.]
Eric Pinon (firstname.lastname@example.org): Ramon, a darker environment (tank color, pond soil) will stimulate the expansion of chromatophores in the shrimp’s shell. Then, at harvest, put them into an icy, high-salinity brine, and they will retain the dark color better.
Daniel Gruenberg (email@example.com): I uploaded this photo (“Organic BT Pigmentation”, June 30, 2013) of our organic tiger shrimp (P. monodon) to the photos section of the Shrimp List. We put a lot of effort into making sure they got maximum pigmentation.
Nelson Gerundo (firstname.lastname@example.org): Daniel, Whoa! Your tigers look great. This is how tigers should look—a dark olive green interspersed by alternating black and white stripes from the base of the carapace down to the last abdominal segment. They are also clean, smooth, firm, shinny and have no sign of rot on the antennal scale and the tail fans.
Daniel, did you select only your best looking shrimp for the above photo? Just kidding, big smile.
Daniel Gruenberg (email@example.com): I get that comment often. I sell full containers of that product and get a premium price for it. Only customers willing to pay a high price get the best stuff!
I should note that those tigers were grown in open ponds that contained lots of copepods and diatoms, not in tanks painted black. When cooked they turn a deep burgundy-red and bright white. I also believe that the deep-colored product has superior fragrance and taste.
I have an interesting anecdote regarding these shrimp. We would often ship samples to Japan for taste testing and evaluation. Our secretary in Japan was a single mother with a daughter in junior high school. The mother would make “Ebi-fry”—deep fried, breaded shrimp—for her daughter because it was her favorite food. After her daughter ate my shrimp, she would no longer eat store-bought shrimp because she could not forget the taste of our tigers!
Nelson Gerundo (firstname.lastname@example.org): I agree with you. Kids love shrimp tempura. In the past, I often ate at “Saisaki” (an all-you-can-eat Japanese buffet restaurant in the Philippines) and noticed kids going first to the Ebi tempura trays and then to he other food items on the buffet table. Old folks would tend to raid the sashimi counter first.
John Birkett (email@example.com): Ramon, to get darker shrimp, try a black cover on top of your tanks.
Nelson Gerundo (firstname.lastname@example.org): Ramon, do you have a picture that you can share with us that shows the gross morphological appearance of your tank-grown shrimp?
To show you the typical coloration of the shrimp reared in a local outdoor pond in our country, I uploaded this picture (“Litopenaeus vannamei, Boone, 1931”, July 2, 2013) to the photos section of the Shrimp List. The shrimp were produced on an intensive farm somewhere north of Luzon, Philippines, and had an average weight of 15 grams after 100 days of growout.
Buyers at our local wholesale market prefer this color.
I did some minor tweaking of the picture in Adobe’s Lightroom 3 and Apple’s iPhoto.
Nelson Gerundo (email@example.com): Ramon, I uploaded another picture (“Penaeus vannamei, Boon 1931, July 2, 2013”) to the photo section of the Shrimp List. It’s a picture from another intensive shrimp farm somewhere south of Luzon, Philippines. The average weight of the shrimp in this picture is about 30 grams after roughly 150 days of growout.
Nelson Gerundo (firstname.lastname@example.org): Daniel, here is a picture (“A. Tribute", October 11, 2012) that I uploaded to the photos section of the Shrimp List. It shows the desirable dark olive green coloration of a live tiger shrimp with alternating black and white stripes from the base of the head down to the tail.
Ramon Castillo (email@example.com): Hello Nelson, I forgot to take pictures of our shrimp during the harvest two weeks ago. But again, our customer mentioned that he prefers darker shrimp. After my next harvest, I promise to take pictures.
In the pictures that you uploaded, the shrimp are much darker than the ones we are producing.
Patrick Wood: (firstname.lastname@example.org): The more you process and wash the shrimp the lighter they become. Many processing plants just scrub the color right out. To get the best color with whole vannamei, it’s best to cook live shrimp.
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