13% arrive dead with strong necrosis severity. 100% of the batch died after 2 weeks with the same symptom. No virus (double tested for 8 virus include strains of ANHPD and NHPb). Shrimp tissue shows yellow colonies around 6x10^5/ml and green around 4x10^3/ml. Bacilus counting in esterelized ozone water used for water exchange showed 3x10^6/ml concentration but did not reduce the shrimp vibrio countings. Tough!!

Hi Fabio,

As you asked: "How melanosis can appear so fast/"

MELANOSIS in shrimp is a harmless but objectionable discoloration or darkening, occurring primarily along the swimmerets, head, tail, and nearby shell areas, before spreading further along shell edges and through the body... which can appear faster than melanization.

https://www.seagrantfish.lsu.edu/program/Melanosis-Fact-Sheet.pdf

Whereas MELANIZATION is a lesion induced by an innate defense reaction to pathogens in infected shrimp to kill and isolate and localize the infection... which can take longer as a reaction compared to melanosis.

https://www.sciencedirect.com/science/article/pii/S0145305X17302665

MELANOSIS in dead shrimp is not the same as MELANIZATION in living shrimp

Nelson.

Tough? No. Just a very basic elementary catchy clever question that can trick any novice pathologist into a trap in his/her very own territorial line or area of profession.

https://www.goodreads.com/quotes/311993-intention-is-one-of-the-most-powerful-forces-there-is

Very much like asking the etiology (or in layman's language, called as causative agent) of the pinpoint pale-hemorrhagic-like discolorations localized between the hepatic crest and submarginal crest of the carapace of this shrimp asked many years ago in another shrimp forum.

https://teacheratsea.files.wordpress.com/2015/06/northern-white-shrimp-litopenaeus-setiferus.jpg

No one answered the question (actually just a tricky question designed to trap someone). Neither did I answer the question... because it is not a sincere question.

No need because it is just a normal phenotypic coloration for this species of shrimp... Litopeneus setiferus (Carl Linnaeus, 1767).

Pathologists study anatomical alterations (called LESIONS, examples, hypertrophy, atrophy, hyperplasia, necrosis, etc.), both gross, microscopic, and ultrastructural in LIVING ANIMALS as a result of tissue reactions to insults caused by (1) genetic predilection e.g. neoplasm, (2) physical agents e.g. radiation, (3) mechanical agents e.g. blunt trauma, (4) chemical agents e.g. poisoning, or (5) foreign biological agents e.g. bacteria, viruses, protozoa, fungi.

While anatomical changes in DEAD ANIMALS are just called outcomes of AUTOLYSIS.

https://www.pathologyoutlines.com/imgau/forensicspostmortemFrench09.jpg

A thing of interest to Forensic Science Investigators and Morticians and Undertakers in the world of the dead in humans.

In addition, NECROSIS only happens in living tissues while the animal is still alive.

AUTOLYSIS, on the other hand, only happens in dead tissues after the animal has died.

Fabio Higa I would demand a refund. There is no excuse for this. 20 hours is not a long shipment. We
received a shipment after 52 hours and they had nothing like what you saw. I am sure these animals showed some
level of this necrosis before they were shipped. Hope it works out for you.

Thanks Hank Bauman ! I was afraid about that too... because of that I came to the shrimp list to see if it´s possible shrimp necrosis happen in less than 24h. Best regards, Fabio

Fabio,

The melanotic areas are localized on the traumatic impact areas of the shrimp shown on the photograph i.e. on the dorsal surface of the 3rd and 6th body segments.

The dorsal surface of the 3rd and 6th body segments are the areas prone to blunt trauma when the shrimp backflip to make an escape reaction that could hit hard objects damaging these areas... especially when a shrimp backflips while being handled and falls on the floor and backflips again multiple times.

With blunt trauma in these areas, necrosis is an inevitable sequela. Although necrosis is often followed with a melanization reaction by the shrimp to close the damaged area that always becomes infected with secondary infection by opportunistic bacteria or saprophytic fungi or a mixture of both, the thing is melanization happens slowly (besides being always preceded by hemocytic infiltration) and cannot occur at the extent shown in the image in under a day (20 hours).... because melanization is a chronic lesion in arthropod (e.g. shrimp, crab, lobster, insect, etc.)

https://www.medicinenet.com/script/main/art.asp?articlekey=2728

However, If those discolorations as shown in the photograph are indeed melanization as a result of necrosis due to blunt trauma that got infected, then it could most likely have progressed to melanosis due to either:

(1) Autolysis because of delay of recovery when the shrimp with blunt trauma injury died long after it has been released in the tank and not at reception after a 20-hour flight... more likely this is the scenario.

(2) Or a shrimp with severe melanized blunt trauma on the 3rd and 6th segments was included in the shipment that died early during transit that underwent autolysis along the way... less likely this is the scenario.

Nelson

Fabio,

Regarding refund as mentioned by Hank, there was one incident in a government-accredited shrimp hatchery on the island of Cebu here in my country, that received a shipment batch of SPF broodstock from an SPF broodstock supplier in Hawaii with a very low fertility rate.

The hatchery in Cebu, owned by a very honest-multi-millionaire man of integrity, received a shipment replacement after he notified the broodstock supplier in Hawaii… The two have a very long business relationship and the first time that the hatchery in Cebu complained after many many many and many importations of high-quality broodstocks over the years from the supplier in Hawaii.

But never any narrated case-story like yours, not even a single incident of transit melanosis accompanied later by all-out broodstock mortality.

Nelson

Fabio, I would do a thorough dry out and disinfection of the facility before receiving another batch of brood.

Extreme severe eroded transit necrosis progressing to melanization then ultimately ending in melanosis in under 20-hours followed by all-out broodstock mortality.

A narrated case-story like yours, which I find, being a pathologist myself, Pathologically very strange, and scientifically hard to believe... because in this case as narrated by your story, it cannot be that the shrimp in the discussion, developed melanization during transit that progressed to melanosis in under 20-hour after it died while still in transit.

Hank Bauman, the necropsy image of the dead shrimp (LEFT IMAGE) with autolytic melanosis manifestations on the 3rd segment and 6th segment, in addition to having eroded melanocytic telson and bilateral fractured antennal flagella, is dated December 27, 2019... It is a 9-month old picture.

Thanks Hank Bauman. I did a full facility dryout before receive them and twice after mortality happened - 40 days fallout ... Even using separated and isolated quarantain tanks.

All shrimp were tagged and sampled individually. All broodstock tested in two different locations after arrival.

Hi Fabio Higa, sorry to hear about your loss. What were the water parameters on arrival? Also did you acclimate for PH? Having 13% mortality on arrival, but then having 87% die within 2 weeks with no disease diagnosis is really strange. I do not know the source of the Broodstock (and I do not want to know), but obviously this batch went through some rough handling somewhere along the way. Just curious what the arrival parameters and acclimation parameters were.

Thanks Robin Pearl. All parameters were normal and we monitor the climatization within all parameters before stock at the quarentaine tanks ( I don´t remember now). All shrimps, from each bag were keep isolated till our test confirm no pathogens presence. Those ones didn´t make it, unfortunatly. Sure those animals suffer a lot during travelling and because of this I´m asking about the melanization time frame. I know if you pack in the wrong time, during molting or pre-molting this can happen with broodstock, but not so fast as we saw when the animals were alive. Not recovering also was quite surprising showing that we had an abnormal situation.

Problems always happen in shrimp farming and here is not a question to blame or name any company or someone, but how to fix it and avoid those issues in the future. We all still learning with shrimp, so sharing information and asking for help at the shrimp list, is something people supose to don´t judge, and try to help the best way you can. Sadly shrimp farming knowledge always means deal with ego, envy and lies from others. More complicate in this digital era, where "respect" is something frequently forgot in any socialization, showing radical deep intolerance with other opinnion.

For intolerant people where public atack someone without knowledge or judging because a ceritificate degree in from their name diserve only one thing: banment from live with others and ostracism to learn how to deal with people in proper maners. For me i just forget those people exist!

Best regards, Fabio

We ship hundreds of thousands of broodstock annually and the travel time can be between 24 and 60 hours. We generally have very good survivals (generally 98%+), but sometimes there are shipments with long delays or unusual handling. Most of the time the main culprit is temperature related. If the animals are packed and shipped in the correct temperature, and the shipper maintains the proper temperature along the way during the whole shipment, then the broodstock nearly always arrive in good condition. Next time you reorder the broodstock have the shipper include a disposable temperature logger. They are inexpensive and the data is usually very surprising. We have seen airlines put the boxes in the refrigerated storage and have seen temperatures decline to about 10C, and we have seen instances where during transfer at a distant airport, the temperatures rose to well over 25 degrees C before cooling back down at arrival.

If only to bring enlightenment to this mystery, I would like to add the following explanation from an objective perspective:

(1) Decomposition in dead animals can be hastened by warmer temperature but the shipment occurred during winter (December 27, 2019) on a 20-hour air shipment (less than a day) when it was cold.

(2) Also, severe melanization doesn’t happen in live shrimp in 20-hour. It takes time for melanization to develop and become severe. More so when caused by blunt trauma leading to secondary infection on the anatomical parts of the shrimp prone to impact injury.

(3) Even those pathogens that are known to stimulate a direct melanization-defense reaction in shrimp take time to develop e.g. Fusarium and Paramoeba.

(a) Fungus
https://www.researchgate.net/figure/Images-of-L-vannamei-gills-A-Normal-gill-of-L-vannamei-B-Black-gill-of-diseased-L_fig1_283655004

(b) Protozoa
https://www.aquaculturealliance.org/advocate/detection-of-an-amoebic-parasite-in-cultured-paci%EF%AC%81c-white-shrimp/

(4) And the lesions caused by these ubiquitous opportunistic Fusarium and Paramoeba occur on the parts of the shrimp not prone to impact injury i.e. gills inside the gill chamber that is covered by the carapace.

(5) Finally, Localized chronic septic necrobiotic melanization as a healing reaction of the injured shrimp due to blunt trauma injury takes time to develop and this condition is not a contagious condition and the other shrimp in the bucket are apparently healthy lacking any manifestation of blunt trauma injury.