Fibropapilloma in Bonaire

The report

At least once a month we scan the Internet for any new instance of the word "fibropapilloma." A March 22nd routine search turned up an article in the newsletter of the Sea Turtle Club of Bonaire announcing the first appearance of fibropapilloma disease on that island.

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We immediately advised the CTURTLE mailing list of this information, and informed George Balazs of the US National Marine Fisheries Service of this situation. In addition, we made email contacts in Bonaire to determine more about the appearance of this disease in that island nation.

The Sea Turtle Club of Bonaire has been especially vigilant and helpful in answering the questions we've asked about the environmental conditions surrounding Lac Bay, where the disease has been reported. Further inquiry resulted in this information:

"In June 1998 the fibropapilloma was reported for the first time. The first dead green with "fibro" was found in November 1998, the second in December and the third in January 1999. They were all big juveniles to sub-adults. All the greens with fibro were seen in or near Lac Bay."

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The interview

As a result of our contacts, Ursula was able to ask a number of questions. The answers were provided by Coen Vos and Ine Wilms:

Q. So let me ask you. In the past ten years... there been any environmental impacts to Lac Bay?

A. No major events.

Q. Runoff perhaps?

A. No run off, this is actually minimised by dams that have been constructed behind Lac, to hold rain water.

Q. Cattle/agricultural impact?

A. Just donkeys and goats, not many.

Q. I went to the Net and noticed this area has two hotels. What kind of sewage treatment do they use?

A. Those two hotels use cesspits and septic tanks, like almost everybody on Bonaire.

Q. Do streams/rivers flow into the Bay?

A. No streams or rivers into Lac Bay.

Q. Know if there are any groundwater discharges near it?

A. No, only a dried up well.

Q. Increased development in that area?

A. No, just a few houses in the neighbourhood, the two hotels and two windsurfing schools (and some local fisherman)

Q. I'd appreciate knowing the kinds of seaweeds. Notice an increase in the abundance and distribution? I mean increasing?

A. No, not that we know of.

Q. Perhaps choking formerly live coral? (That's what happened to us).

A. No, not that we know of.

Q. And two seaweeds I very much want to know about. Red Hypnea (Hypnea musciformis) and Acanthrophora spicifera. I know both grow in the Caribbean.

A. In Lac Bay we have Acanthrophora spicifera, but not the hypnea musciformis. But we do have Hypnea cervicornis. For other seaweed, see attachment 'seaweed'. This information was taken from the Base-line ecological study (1993).

Q. There is growing evidence that occurrence of FP is related to human-impacted near shore environments. Lagoonal perhaps, low flushing...?

A. Low flushing in the part of the bay where the mangroves are growing. The area is very densely populated with mangroves. So the bay itself is flushing well, but the area behind the bay is not. Until recently (maybe 15-20 years) there was more activity in the mangrove area. Local fisherman and others used creeks which they kept open by cutting away the mangroves. This has not been done for quite some time which may have resulted in less flushing.

Q. Oh... and if your island has a sewage treatment plant, where is it and how long has it been operating?

A. There's no central sewage treatment plant, nor a centralised sewage system. Two hotels have a small sewage treatment plant of their own, but they do not work properly. All the collected waste water is transported by truck to a place in the middle of the island, where it is dumped. This is not in the neighbourhood of Lac.

Q. Have you taken water samples to measure water quality specially nitrogen, phosphate and E. coli?

A. Some samples were taken for the base-line ecological study, but this research was done in 1993. We are looking for more accurate data at this moment.

Q. Just know, Ine, that Bonaire doesn't have to go this alone.

A. We appreciate that very much!

More information

We returned to the Internet, did a search for the exact phrase "bonaire sewage" and dug up a report on a proposed Bonaire sewage treatment facility. The article describes a plan that would provide for a way of processing sewage from the hotels. The consultants warn that if such a sewage treatment system is not put into place, nutrient pollution build-up on the reefs could damage or even destroy Bonaire's top tourism attraction, leading to economic disaster for the island.

In the meantime sewage from the two hotels and windsurfing schools around Lac Bay are driven by truck to the middle of the island and "dumped". We have yet to find out what "dumped" means.

The turtle

These are pictures of the stranded turtle. We would judge this turtle as having an overall tumor score of 3: heavily afflicted.

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In our experience, it takes three years for a Hawaiian green sea turtle to reach this point once it becomes FP symptomatic. This suggests this turtle showed the first subtle signs of FP some time in 1995.

Our own observations show that turtles new to our dive site require, on average, two years before they show the first hint of fibropapilloma disease. In the third year, 80% of juveniles have acquired FP. This indicates that the turtle might have been exposed to the fibropapilloma agent/insult in 1992 or 1993. It would be interesting to know more about the ecology of Lac Bay in those years.

The opportunity

At the 1996 Sea Turtle Symposium, the Sea Turtle Club Bonaire presented a poster entitled:

THE SEA TURTLE CLUB BONAIRE 1995 PROJECT: RESEARCH ON RESIDING JUVENILES, INCLUDING A PHOTO-IDENTIFICATION TRIAL

The abstract for this poster read:

The Sea Turtle Club of Bonaire is a non-profit, non-governmental organization, its main goal being the conservation of the sea turtles around the island of Bonaire (Netherlands, Antilles). A main part of the activities in 1995 consisted of in-sea research on the local juvenile green and hawksbill sea turtle populations residing in the unspoiled coral reefs and sea grass beds around Bonaire.

Through a large sighting network of divers and snorkelers, the juvenile populations have been monitored continuously for six months. More detailed information was collected through direct observations on several "turtle hotspots" around the island. Also included in the 1995 project was a photo-identification trial. The goal was to identify individual sea turtles by means of taking slides of juvenile sea turtles at a fixed location throughout the project. The location chosen was the reef in front of Lac Bay. At daytime, an estimated amount of over 30 green turtles and a few hawksbill turtles reside along this reef. The thought is that the green turtles (both juveniles and subadults) reside here all year round, migrating in to Lac Bay at night in order to forage in the sea grass beds.

Since the STCB has photo identification for 30 green sea turtles from Lac Bay in 1995, there is an unprecedented opportunity for researchers to determine the fate of these 30 in 1999!

In addition, it is important to determine what it is their green turtles feed on. As was pointed out, there are various types of algae in this bay, including Acanthrophora spicifera and Hypnea cervicornis. Both these algae are present at our dive site and in the Indian River Lagoon system, FP hotspots.

Considering that FP researchers have found "preliminary the provocative evidence" linking the presence of certain dinoflagellates to sites with high FP prevalence, and that these dinoflagellates use algae as a resting substrate, we believe that a golden opportunity has presented itself in Bonaire. We urge that algae samples from Lac Bay be examined for the presence of these organisms.


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