Category: turtles

Stony Coral Tissue Loss Disease: Threatening Caribbean Reefs, Wildlife and Ecosystems

This is a follow-up publication on Stony Coral Tissue Loss Disease. It describes the findings in the coral reefs in the Cayman Islands during a week in mid April, 2024. The travel to the island was reasonably easy and the accommodations onboard the live-aboard cruise were good. The conditions of the reef life and tropical fish however was disheartening. We have a big problem.

The featured image was made from a view of the sunset from the port on Grand Cayman island. The sunset may be symbolic of the future diving in the Caribbean. I hope that there is a recovery in the future.

As reported in four previous posts (Death in Paradise), there is a continuance of even greater proportions seen during this trip. I reported on the findings on the reefs around Roatan Island off the coast of Honduras two years ago. The condition of the reefs showed considerable loss of the polyp life because of Stony Coral Tissue Loss Disease (SCTLD). It was quite extensive and showed nearly 70% loss of life. At night the coral showed a significant loss of fluorescence because of the large dead areas of coral polyps. During the day one could see the areas of exposed stony skeleton of the reef.

The reef at multiple sites of the Cayman Islands including Grand, Little and Brack, has been devastated by the disease. The population of the reef fish is also significantly diminished. I did not make a count of the fish or of the areas of dead coral. Because of the extent of the dead coral there was no reasonable way for me to make an accurate comparison. It was very distressing. With the option to make 20 dives I made only 12. There was nothing worthwhile to see. I would estimate more than 80% to 90% loss of polyp life. 

In conversation with other experienced divers on board the ship they said that they saw similar conditions across many of the Caribbean islands from Bonaire to the Mayan coast. Generally, they were unaware of the cause of the polyp depletion but said that it looked the same as in the Caymans. The less experienced divers were unaware of the problem and were happy to be in the warm water (85.5 degrees F). There was still some interesting wildlife but is was very reduced when compared to the concentration I had seen as little as 5 years ago. 

50% of central coral head is dead. All of the surrounding coral is dead.
Coral completely over run by SCTLD.
70% of brain coral is dead. Surrounding coral is lifeless.
nderwaterOther areas typical of the reefs showing the discruction of the polyps.
Lion fish (Invasive)
Caribbean Spiny Lobster (Panulirus argus) It was good to see a lobster but formerly there were dozens.
Mating Flamingo Tongues (Cyphoma gibbosum)
Lettuce Nudibrank (Elysia crispata)
Hawksbill turtle (Eretmochelys imbricata) Critically endangered.
Rough file clam (Ctenoides scaber). Similar to the disco-clam seen in the Palau reefs.

There was still life in the Caribbean but it may be below the 100-foot depth accessible for divers and also for much of the live that requires light. The life forms that were readily apparent were mostly bottom feeding animals. Sponges and soft fans were still alive and did not seem to be affected by the SCTLD.

The effects upon the economy that are a result of reef polyp loss are not readily available, however, many of the recreational hospitality workers are questioning their future employment opportunities. I suspect that there may be some resistance in these businesses to make these issues more public.

There has been some publication of the research into the cause of the disease and it seems that researchers have identified an infection. “Results suggest that the bacterial community may be involved in SCTLD, but other members of the holobiont (i.e., viruses and Symbiodiniaceae) may contribute to lesion progression”.1, 2

Vectors and process of viral action is not yet publicized 3. One should not expect a recommended solution for a cure until much further research will be done. I anticipate that it may take decades and that the reef corals will not survive at the current rate of disease progress. This has a direct impact on the southwest coast of Florida.

If you have observed the effects of SCTLD in other areas of the Caribbean or other places in the world please engage in the SCTLD dialogue in the discussion board.

References: Where 2. and 3. are specifically related to work done in Florida reefs.

1. A meta-analysis of the stony coral tissue loss disease microbiome finds key bacteria in unaffected and lesion tissue in diseased colonies

2. Microbial Community Shifts Associated With the Ongoing Stony Coral Tissue Loss Disease Outbreak on the Florida Reef Tract

3. Viral-Like Particles Are Associated With Endosymbiont Pathology in Florida Corals Affected by Stony Coral Tissue Loss Disease

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#SCTLD #Stony coral tissue loss disease #coral #turtle #nudibrank # Flamingo tongue #coral polyp #file clam

Cooperation of Wildlife and People: Bonita Bay Pond #47’s Ecological Success – Part #1

This is a story of cooperation among people and wildlife in the Bonita Bay community. This description is divided into three postings including the macro biology, micro biology and geochemistry. Pond #47 is in my backyard. The freshwater pond was inundated by sea water to a depth of 10.3 feet above MSL. The flood was a climatic challenge to the entire four square mile community property including all 64 retention ponds. The good news is that recovery is well on the way to near normal conditions.

This first of three postings shows the macro biologic content of the pond. This small body of water is in the Bonita Bay residential community in the city of Bonita Springs, Florida. It was artificially constructed nearly 40 years ago as part of a larger hydraulic system intended to manage the surface water of the community property. The property is bounded by Spring Creek to the north, Imperial River to the south, Bonita Bay to the west and highway 41 to the east. There are five animal phyla represented here and they are all thriving. There are also four plant phyla.

The featured picture is one of hundreds of halloween pennant dragonflies that were so full of beautiful color. I had to share it with all of you.

Fish:

Net casting was done to collect fish samples and to check the varieties. It shows the net hitting the water, the clarity and depth, and the light-colored ring patterns in the water are spawning nests created by resident tilapia in the sandy bottom. Other techniques included fly casting and spin casting with artificial bait. Six fish species were caught from the Anchorage Pond #47. They included Mayan Cichlid, Blue Gill, Tilapia, Largemouth Bass, and Snook. Numerous minnows were seen but not caught. Neighbors who regularly fish the pond suggest that there are more Tilapia and fewer Snook since the Ian hurricane. 

Blue gill on top, Tilapia (?) on bottom
Tilapia or Gulf Killfish (Non-Native)
Mayan Cichlid (Mayaheros urophthalmus) (invasive)
Snook (Centropomus undecimalis) (Non-native)

Reptiles:

Alligators and turtles live easily in the pond. The alligator population is variable and although it usually has one. During mating season there were at least two. The turtle population is greater than the alligators and from observation there are always at least four swimming near the surface. During the day these reptiles and crawl out of the ponds to lie on the banks.

Soft shell turtle  (Apalone ferox)
Mating alligators
We’re done.

Marine Crustaceans:

One marine crustacean type was found. Three Blue crabs were found in the water along the shore. These were probably brought in by the hurricane.

Blue crab (female), (Callinectes sapidus)

Birds:

The number and species of wading birds is highly dependent upon season and weather. The birds may select those areas of the shoreline which are favorable to their food and which may be protected from predators by alligators. Here are some of the birds in the shore line vegetation hunting and eating with the alligator in their midst. The osprey was standing quietly watching from the close by tree. These birds were seen in March/April. The birds included Great Blue Herron, white and tricolored Herron, Ibis, ducks, Wood Stories, Anhinga, and Osprey.

Blue Herron
Anhinga caught a Mayan Cyclid
Great White Herron caught a minnow
Stork and Herron ignoring one another
Tricolor Herron searching for fish
Ibis in group of about twenty
American Osprey (Pandion haliaetus) waiting in tree

Insects:

The most obvious insect which could be attributed to the pond were standing or feeding on the pound shore line. The dragonflies observed were exclusively the Halloween Pennants and were in the hundreds. The White Peacock butterflies were flying about in small groups or pairs just on shore near the grass.

Halloween Pennant Dragonfly, (Celithemis eponina)
White Peacock butterfly (Anartia jatrophae)

The diversity of the wild life supports the eutrophic designation of the pond. Further examples of this follow in the next two presentations. They include the plants and the microflora with geochemistry. Be sure to see them too!

This story is similar to the previous posting on a river restoration project found in Fulda, Germany.

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See the discussion board to engage with like minded naturalists and photographers or to open a new topic to share your thoughts. https://evergladesark.com/2024/04/25/discussion-board/

#Pond #Recovery #fish #insects #crustaceans # dragonfly # butterfly # turtle # Herron # Mayan Cichlid #Snook # Blue gill #bass #Osprey #White Peacock #alligator

Costal Wetlands Ecosystems of SWFL, Part 4, Turtle Nest and Gender Assignment

While walking along a very low traffic area on the southern end shoreline of Fort Myers beach, turtle activity was easily seen. The nest was two meters inside of the bird restricted area. A closer investigation was ill advised. The turtle traveled about 40 meters from the shore in the early morning to lay her eggs, bury them and then returned to the sea. There was no sign of other human traffic in the area. The picture was made at approximately 9:00 AM.

The Green sea turtle in the feature image was made in the Caribbean in a reef system 5 miles off of the coast of Belize.

For a more comprehensive description of instrumentation see the previous posting on Soil Thermometer Exploration. Also see Costal Wetlands in SWFL Part 2

Path from shore to nest appears to be from a green turtle. There is no center tail track between the fin marks.
Soil temperature 26.4 C, 3 meters from nest at 20 cm depth.
Sea turtle egg nest recently buried
Green Sea Turtle 80 feet under water, in reef 5 miles off the coast of Belize.

Using my foot print in the sand as a reference you can see that the path is little wider than one meter (~120 cm). Turtle fin prints have an alternating step pattern and there is no central groove in the sand in the center of the track between the fin prints. The more common turtle here would be the Logger Head. The markings of this track suggests that this was made by a Green Sea Turtle. Considering the activity, the distance from the water, the opening a hole in the sand, the laying of estimated 80 eggs, the covering of the eggs with sand and the returning to the water, this experience must have taken at least two hours. There were no other predator foot prints on the sand.

Proposed research:

Observation: Sea turtles and apparently many reptiles exhibit temperature dependent sex determination (TDSD)*. A sufficient level of research on TDSD has been done. My recordings over the last two days in nearby sand areas at various times suggest that the sand temperature should rise from the noted 26.4 C to a higher temperature between 29 C and 31 C by mid day. If the average temperatures remain in that range or lower during the entire day, there should be significantly more than 20% male offspring. With the knowledge from previous research the more appropriate prediction would be at least 80% female hatchlings.

There is a problem with failure to have gender diversity from turtle hatchlings on the beaches of Florida***. Findings in Florida beaches show abnormally high percentage of female hatchlings. This is apparently the result of average higher temperatures. It is also projected that with rising temperatures the shortfall in the male population will result in a colony population insufficient to sustain its current level. I suggest a simple attempt to reverse the gender trend. Here is a pilot project proposal:

Purpose: Is it possible to control sand temperature thereby controling the gender of turtle hatchlings at the beach?

The null hypothesis: The sand temperature at a depth equal to or greater than 20 cm would rise to 30 C or more for a significant period during the day regardless of attempts to stabilize it.

Method: Measure the change in sand temperature in a specific location of costal beach. It should be continuously recorded relative to change in time consistent with a projected egg incubation period. Include the variables of a specified period of the year and selected location. Test an interventional variable such as application of a controlled volume of sea water to the surface of the sand in the test location. The water volume should be less than the absorptive capacity and capillary action of the sand below 10 cm.

Discussion: If the null hypothesis is disproven and data revealed a regular pattern of temperature stabilization within a specific range at a depth of 20 cm, one should be able to predict the male / female ratio of the expected hatchings**. If this research shows a favorable result there may be a remedy for the diversity shortfall. Proactively, the genetic population of the nest might be regulated by cooling the nest through the timely addition of a controlled volume of water. The effect of the water would be immediate cooling of the surface and a delayed effect resulting from water evaporation. If this is effective it would thwart the risk of having an excess of female turtles or an insufficiency of male turtles. If this pilot study shows benefit this may be applied to a larger area such as selected nests along several miles of beach. A volunteer effort could support this type of effort. Please read the thought provoking references below.

If you are interested in the effort to support gender diversity in the turtle populations please share your comments.

References:

*TDSD via STAT phosphorylation at the warmer, female-producing temperature

**Figuring out the genes that let reptiles use temperature to determine sex

***Hotter summers mean Florida’s turtles are mostly born female

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#turtles #nest #temperature #reptile #gender #TDGD #sand #beach #thermometer #eggs #reptile #population

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