Bubbles from the Naturalist Jerry's tank - by Jerry Ligon

Information on 2008 Moray Mortality on Bonaire

LATEST INFO ON MORAY MORTALITY ON BONAIRE, FALL 2008

We became alarmed in mid-summer when dead moray eels started being reported here on Bonaire. I posted a request on Bonairetalk.com in order to establish a forum where visiting divers could report their sightings, and I put the word out at Bonaire Dive and Adventure, where I am employed, for divers to report to me directly when sighting any morays that seem abnormal in any way. Sure enough, the reports started coming in through these two venues. By late October, I had recorded 50 dead morays, with many more being seen I am sure, but not reported.

Following is the preliminary report sent back to Bonaire after Professor Bert Williams visited Bonaire.

 

REPORT ON THE EXAMINATION OF A MORAY EEL MORTALITY IN BONAIRE

Ernest H.(Bert) Williams, Jr., Department of Marine Sciences, PO Box 9013, University of Puerto Rico at Mayagüez, Puerto Rico 00681

Lucy Bunkley-Williams, Department of Biology, PO Box 9012, University of Puerto Rico at Mayagüez, Puerto Rico 00681

In July moray eels began dying in Bonaire, Netherlands Antilles. We were notified and Bert was invited by Ramon de Leon of Bonaire National Marine Park, STINAPA, and Rita Peachey of CIEE Research Station to investigate. Rita had already conducted a number of necropsies and Ramon and Jerry Login were keeping summaries of the mortalities.

Bert traveled from Mayagüez in western Puerto Rico, to San Juan, and to Bonaire 21 October 2008. CIEE had been obtaining rather fresh eels for necropsies, but while he was there, they only obtained decomposed ones that were not much use for isolating a pathogen.

Two dead eels were reported, but not collected almost in front of the lab 22 October. When they received no new cases on 23 October, Rita and Bert snorkeled in the area for 1.5 hrs looking for dead eels.

At the "eleventh hour" 25 October around 4 PM, they obtained a fresh eel. Bert was able to take mucus samples to preserve in ethanol and in buffered formalin and tissue samples of the hemorrhagic intestine and body wall. He also prepared and examined microscopically samples of external mucus, mucus from the intestine, mucus from hemorrhagic areas of the intestine, gill smears, and gross gills. Early the next day, Bert traveled back to Puerto Rico with the preserved samples.

We think we have isolated a possible pathogen, but tests are still pending. We are preparing the mucus samples for electron microscope examination. We are preparing the samples of hemorrhagic intestine tissue for histological sectioning and analysis. Unfortunately, a strike closed the University for a week and held up our study.

In cooperation with Ramon and Jerry, we have assembled a list of 75 individual fish that died. Most (65, 93.3%) of these were morays (Family Muraenidae) and snake eels (Family Ophichthidae) (43 Spotted Moray, Gymnothorax moringa; 13 Green Moray, Gymnothorax funebris; 7 Mulatto Conger [Viper Moray], Enchelycore nigricans; 4 Sharptail Eel, Myrichthys breviceps; 1 Chain Moray, Echidna catenata; 1 Goldentail Moray, Gymnothorax miliaris; 1 Purplemouth Moray, Gymnothorax vicinus). A few (5, 6.7%) were other species (2 parrotfish [Family Scaridae], 1 Creole Wrasse, Clepticus parrae [Family Labridae]; 1 French Angelfish, Pomacanthus paru [Family Pomacanthidae]; 1 Yellowtail Snapper, Ocyurus chrysurus [Family Lutjanidae]). We are still trying to create a complete list with all the records recorded by Ramon and Jerry, to confirm all of the identifications (such as the "parrotfish" above), record the latitude and longitudes of each locality, and list the those observers who reported each dead fish.

We have not received the complete necropsy reports and photographs, but I believe only Spotted Morays, Green Morays, and a Purplemouth Moray have been necropsied. Possibly, 2 Mulatto Congers were examined the day after I left. We can probably safely assume that the other two species of moray eels were suffering from the same condition, although it would have been preferable to examine each species. We can be less certain about the snake eels and much less certain about the four or five other fish species in four different families. Examining some of the non-eel species is particularly important in resolving how broad this event was in attacking fishes of different species and different habitats and behaviors. Unfortunately, we have not been able to obtain samples of any of those fishes.

Roberto Hensen and Mark Vermeij examined moray eels form a similar mortality that occurred in Bonaire in 1995. Eric Newton gave Bert Roberto's e-mail address. Bert contacted Roberto about the kill. Ramon also e-mailed Roberto and contacted Mark. Roberto remembered little about the mortality except that it was relatively short. Mark remembered that the eels had head and lateral line lesions. We need to know what time of the year the mortalities occurred, where in Bonaire, which species of moray eels died, and how many. Roberto thought there was a report, but could not find a copy.

We have learned of another moray eel mortality on another Caribbean island in another year. We are in contact with biologists from this island and are trying to obtain the details of the event. We cannot be certain the two are related until we have more information.

If there was a third event on another Caribbean island, then there may be more. We also need to obtain as many records from the present event as possible, particularly in the beginning of the event to accurately establish when it began. We have prepared an announcement requesting records from the members of the Association of Marine Laboratories of the Caribbean, the AMLC Newsletter, Coral List, and other fish, disease, and diving networks. We need as many details from as many events as possible.

If we can obtain details from all three (or more) events, we may be able to establish commonality and find what initiated the events. Bert believes he has a pretty good guess, but Lucy wants more information before she will accept his idea. Bert believes he is close to confirming what started these events. This is the most difficult thing to learn retroactively in mortalities. It is also the most important thing.

I believe we will establish what started the events and the disease agent which took advantage of weakened animals to continue the events. We intend to publish this information with all those involved in this investigation.

Then, in late November, 2008, Kara Kozak, a student at CIEE, a newly arrived center for marine education here on Bonaire, presented a power point presentation to the public, which summarized the findings reported back to us from Dr. Williams, from Puerto Rico, and from the professors at CIEE, who were working in conjunction with Dr. WIlliams. CIEE staff were performing autopsys on the collected dead eels and one can download their findings.

Also, a very revealing video, taken by one of the visiting divers, diving on Bari Reef, shows the final death throes of a spotted moray. See this video on Youtube by clicking on the following:

COMMENTS FROM JERRY

in SUMMARY, THE EELS WERE BEING AFFECTED BY A BACTERIA, CALLED VIBRIO. ONE OF THE SPECIES OF THIS GENUS IS THE CAUSATIVE AGENT IN HUMAN CHOLERA. IT SEEMS PRETTY GRUESOME FOR ANY CREATURE TO BE INFECTED WITH THIS TYPE OF BACTERIA, WHICH CAUSES ALL STOMACH CONTENTS TO LIQUEFY, AND ABDOMINAL PAIN WITH BLEEDING FROM THE GASTRO-INTESTINAL TRACT, RAPID LOSS OF WATER FROM THE SYSTEM, AND IN EXTREME CASES, DEATH.

THEN, WE HAD A BLESSING IN DISGUISE, WHEN ON OCTOBER 13, HURRICANE OMAR FORMED NORTH OF BONAIRE. WE RECEIVED HEAVY SURF WHICH POUNDED THE LEEWARD SIDE OF BONAIRE WHERE MOST OF BONAIRE CONDUCTS LIFE. MANY CORAL HEADS WERE OVERTURNED, SPONGES WHERE BROKEN, AND VEGETATION WAS KILLED BY THE MASSIVE SEA SRAY OF SALT WATER. IT WAS QUITE REVEALING TO SEE THE VEGETATION ALONG THE ROAD AT 1000 STEPS TOTALLY DEAD, WHICH IS 50 OR SO FEET AWAY FROM THE OCEAN. THIS ALSO OCCURRED ALONG THE ENTIRE WESTERN COAST OF BONAIRE. THE CAPPUCCINO BAR, OUT ON KAREL'S BAR DOCK WAS TOTALLY DESTROYED AS WERE A LOT OF PIERS ON BONAIRE.

THE GOOD NEWS FROM THIS NATURAL PHENOMENON WAS THAT IT MUST HAVE CLEANSED BONAIRE OF THE SOURCE OF BACTERIA BECAUSE ONLY A FEW MORAYS WERE FOUND DEAD AFTER OMAR. THOSE THAT WERE FOUND DEAD WERE MOST LIKELY INFECTED JUST BEFORE OMAR, BECAUSE SINCE OMAR, NO MORE DEAD MORAYS.

ON RECENT DIVES, DURING DECEMBER AND JANUARY, I HAVE NOT SEEN NOR HEARD OF ANY REPORTS OF DEAD MORAYS. THE HEALTHY MORAYS THAT I AM SEEING ARE MOSTLY IMMATURE, WHICH SEEMS TO INDICATE THAT THIS NEW AGE CLASS APPEAR TO BE HEALTHY. OMAR ALSO CLEANSED OUT ALL THE THICK REDDISH ALGAE THAT WAS COVERING THE BOTTOM AND SECTIONS OF CORAL RUBBLE ALONG THE ENTIRE WESTERN COASTLINE OF BONAIRE AND MANY SECTIONS OF KLEIN. THIS SOURCE OF ALGAE WAS DETERMINED TO BE THE SIGNATURE OF A DEATH WARRANT FOR BONAIRE'S FAMOUS REEFS. RESORTS WERE INSTRUCTED TO NO LONGER FORGET ABOUT HAVING FULL SEPTIC COLLECTION SYSTEMS PUMPED OUT AND HAULED TO THE CENTER OF THE ISLAND. ALL RESORTS, HOPEFULLY ARE NOT ALLOWING THEIR SEWAGE TO ACCUMULATE AND OVERFLOW TO THE COASTAL REEFS, BY INSTITUTING A REGULAR SCHEDULE OF HAULING BY THE "HONEY TRUCKS". THIS TEMPORARY SOLUTION IS A PLAN TO ALLOW FOR THE CESSATION OF CORAL DAMAGE UNTIL THE SEWAGE TREATMENT PLANT CAN BE BUILT, WHICH NOW LOOKS LIKE 2012. AS RAMON POINTED OUT IN HIS MESSAGE TO THE ISLAND OF BONAIRE, "THE CORAL CANNOT WAIT THAT LONG WITHOUT BEING DESTROYED.