7. The use of Interceptor as a drug against T. acroporanus. This drug was used in multiple trials at a local coral farm (Reef Savers) heavily infested with the copepods. Despite the presence of many species of corals at the time, only Acropora were colonized. Interceptor was obtained from my local veterinarian for trials. A 90 gallon tank was used to treat the many infested Acroporids and smaller tanks used to determine dosages. Dosages were initially followed according to Dortonââ"šÂ¬Ã¢"žÂ¢s protocol. Three doses were used, and it was determined that all copepods were eliminated after two doses in about forty specimens of Acropora. Verification was obtained by careful examination of each specimen under a dissecting scope. Although some copepods remained attached to the coral, they were dead showing no signs of movement or life. Even so, they were difficult to remove from the coral, even with a pipette. Dosages were increased to 10X and 100X the recommended dosage, and corals were grossly unaffected. However, it should be noted that virtually all over associated organisms died, including barnacles, polychaete worms, amphipods, copepods, and associated crustacean fauna (coral crabs) at all dose levels. Therefore, I would suggest that Interceptor appeared to be very safe for corals, but not for other organisms in tanks that may be present at a high bioload and also make the suggestion that ââ"šÂ¬Ã…"œin tankââ"šÂ¬Ã‚ treatment can result in an unacceptably and potentially dangerous loss of infauna biomass. It is my feeling that corals should be removed from tanks and treated alone in a treatment tank, regardless of the potential inconvenience of removing large, attached and established acroporids. There has been no study of the effects of the drug on corals or on other organisms that do not die outright, and there may be significant impacts that are not grossly visible.
In a separate experiment, acroporids colonized by T. acroporanus treated with a 5x dose of Interceptor resulted in the death of the corals, nor resulted in the death of all copepods, but it is unknown if the drug or other factors caused the mortality. There were also tapered elongate flatworms present at the skeleton tissue interface unaffected by Interceptor that may have played a role in the continued tissue loss, but again this is an unknown flatworm and effect of these symbionts. In any event, a second trial seemed to be relatively ineffective in killing T. acroporanus.
These conflicting studies demand the establishment of an LD50 for both parasite and corals. This aspect is currently being studied in subsequent trials in the Barse lab, Unfortunately, the associated flatworms did not survive the transport, and efforts are currently underway to provide another sample of flatworms.
It should also be noted that Inteceptor dissolves poorly in seawater, and it I suggest that the drug be dissolved in the smallest possible amount of DMSO in which it and all the filler ingredients dissolve readily, allowing a more precise dosing concentration, and DMSO does not seem to negatively impact the results on coral or parasite
8. Other treatments:
a) Rid: an over-the counter medication to treat external skin lice, the drug was effective in removing copepods. There appears to be a surfactant present indicated by a foaming action upon application that may collapse respiratory structure of the copepod. The effect on corals was moderate, with heavily colonized corals showing the most severe effects with some corals lost during treatment, although a small number. Furthermore, this treatment may be effective using more carefully controlled dosages.
b) Lugolââ"šÂ¬Ã¢"žÂ¢s solution: We used two high dose Lugolââ"šÂ¬Ã¢"žÂ¢s dips as a method of dipping to kill copepods. Within about 30 seconds, most copepods had bailed off the corals, and fallen to the bottom of the treatment vessel, rapidly dying and turning black. Several corals maintained attached to the coral but were dead. The dose level was 5m/L and up to ten minutes was tolerated by even highly colonized corals, although the effect on the coral was seriously stressful, resulting in partial bleaching, abnormally increased mucus production, and in a few cases, death. The majority of corals survived and recovered within a week and without any copepods present. The duration of treatment varied from 3-10 minutes, and examination under a dissecting scope was done every minute to assess the status of the parasites. At 10ml/L, copepods died generally within 30 seconds, with some lasting up to 2 minutes. The effects on the corals were more pronounced and resulted in significant mortality, especially at durations from 2-5 minutes. This may be a good ââ"šÂ¬Ã…"œdipââ"šÂ¬Ã‚ method for minimally colonized corals that can tolerate the high dosage of Lugolââ"šÂ¬Ã¢"žÂ¢s solution.
c) Heartguard: another veterinarian medicine comprised of a different ingredient, In general, the drug did not have a significant effect on corals or T. acroporanus.
d) Freshwater dips: these are inherently stressful to the corals, and although most tegastids abandon the host, it is not particularly effective in killing the copepods.
e) Doramectin: a saline injectible and soluble solution that is as effective as Interceptor in its minimal effects on coral and maximal effect on parasites. It is available as primarily bovine injectable and is soluble in seawater and thus provides a more controlled dose, It is, however, effective in much the same way in Inteceptor with a similar mode of action, it is harder to acquire and is expensive.
TO be continued...