With thanks to my colleague (Ari) who’s a member of the WAVMA, he’s shared this new finding. For a long time, HLLE has been a difficult to diagnose condition because of the multifactorial nature. New evidence suggests the use of activated charcoal is contributory.
And in another article, it found that the loose/powdery lignite carbon is worse than pelleted carbon.
It’s these new gems of relevant and practical information that I’m definitely including for my next edition of Fish Vetting Essentials.
Check out the abstract of one of the mentioned articles below:
Effects of full-stream carbon filtration on the development of head and lateral line erosion syndrome (HLLES) in ocean surgeon.
Source
Walt Disney World Resort, Epcot, The Seas, 2016 North Avenue of the Stars, Lake Buena Vista, Florida 32803, USA. andy.m.stamper@disney.com
Abstract
Head and lateral line erosion syndrome (HLLES) is a common but very poorly understood disease of marine aquarium fish. One suspected etiology is the use of granulated activated carbon (GAC) to filter the water. Seventy-two ocean surgeons Acanthurus bahianus were distributed among three carbon-negative control systems and three GAC-treated systems such that each tank contained approximately the same total body mass. Each replicate system was made up of two 250-L circular tanks with a common filtration system (6 fish per tank, 12 fish per replicate system). The GAC-treated tanks were exposed to full-stream, extruded coconut shell activated carbon, which produced a mean total organic carbon content of 0.4 mg/L. The results of this study indicate that extruded coconut shell activated carbon filtering at full-stream rates can cause HLLES-type lesions in ocean surgeons. The HLLES developed exponentially over 15 d, beginning in the chin region. This was followed by pitting in the cheek region, which expanded until erosions coalesced. Once the carbon was discontinued, the processes reversed in a mean time of 49 d. As the lesions healed, they reverted from the coalesced to the pitted stage and then darkened before returning to normal.
Certainly never investigated as a Government aquaculture facility but almost surely stamped on as as aquaculture staff were presenting with symptoms of noise stress (in air) and subsequent hearing loss.
A hole in the head outbreak occurred in a marine aquaculture facility, no carbon involved, that coincided with in air noise levels that breached WHOS Standards and in turn generated over the top underwater noise levels.
Given better understanding of underwater noise impact on marine organisms now I would suggest that the fish may have experienced massive stress from extreme noise levels that has been show to dramatically change hormone levels.
Hole in the head is associated with stress isn’t it?
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That’s a possibility, but I’ve not come across papers finding associations between noise and HLLE. In murray cod, a condition termed erosive dermatitis with similar gross presentation was associated with using well water. Seems to be more a syndrome than a disease.
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