HOLOTHURIA FLORIDANA PDF

Print Send Add Share. Notes General Note: Holothuria floridana is found throughout the Florida Keys, USA with different distributional patterns occurring between large and small phenotypes. Their abundances are high in seagrass beds, where they can significantly reduce benthic microalgae. Environmental variables and sediment characteristics also correlate with their distribution and abundances in these areas. To understand their morphological adaptations, ossicles and reproductive organs were compared.

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Print Send Add Share. Notes General Note: Holothuria floridana is found throughout the Florida Keys, USA with different distributional patterns occurring between large and small phenotypes. Their abundances are high in seagrass beds, where they can significantly reduce benthic microalgae. Environmental variables and sediment characteristics also correlate with their distribution and abundances in these areas. To understand their morphological adaptations, ossicles and reproductive organs were compared.

Large and small H. A tethering study was conducted to interpret their relative susceptibility to predation. Predation occurred most often in the lower Keys, in hard-bottom habitats, and on small H.

To assess foraging impacts on sediment characteristics, an enclosure study was conducted in which H. Addition of H. Vegetative cover-abundance, sediment depth, canopy height and sediment characteristics were measured to understand correlates with H. Sediment depth, percent cover-abundances of Thalassia testudinum, total macroalgae and sediment chlorophyll a were significant drivers of their distribution.

In sum, this knowledge will help build a foundation for conservation and informed management. Furthermore, potential food sources for higher trophic predators, such as sea turtles, and seagrass health, which has already been declining in the Florida Bay, will be negatively impacted with overharvesting.

They have supported me throughout my life and have continued doing so through out my duration here at University of Florida. I want to acknowledge Dr. Donald Behringer for being my advisor and all his h elp guiding me through my project He has pr ovided me with a wealth of knowledge on experimental design and experimentation.

I woul d also like to acknowledge my committee members; Dr. Shirl ey Baker and Dr. Antonio Baeza for helping me strengthen and centralize my project and providi ng me with intellectual input I am also grateful for Karen B ray and Cynthia Hight, who provided me with important deadlines throughout my time here.

Without their help, my plan of study would not have been kept up to date and I would not have taken the most influential classes that I did. I would also like to thank Dr. Ed Phlips Leslie Landauer, and Dr. Patrick Baker for their involvement in processing my chlorophyll a and grain size sediment samples. I could not have asked for better mentors for understanding the methodology Furthermore, in analyzing and interpreting my data I want to give an incredible thanks to James Colee, as he explained statistical tests to me in the most basic of ter ms, allowing me to easily manipulate my data Finally, I would like to acknowledge every friend and family membe r that has helped me conduct field survey in the Florida Keys as they were the backbone to my project.

Grain size distribution was used as a covariate. Contribution strengt h of each variable is denoted in standardized coefficients beta column, which determines if the respective Black ovals denote all study sites per each objective. An imaginary line of demarcation is seen s. Error bars represent 1 SE. The dorsal body wall was cut, posterior to anterior, to keep mesentery in t act. Foam rubber was used to prevent holothurians from escaping or entering, while allowing light penetration.

T heir abundances are high in seagrass beds, where they can significan tly reduce benthic microalgae. Environmental variables and sediment characteristics also correlate with their distribution and abundances in these areas T o understand their morphological adaptations, ossicles and reproductive organs were compared Large and small H.

Predation occurred most often in the lower Keys in hard bottom habitats, and on sma ll H. Vegetative cover abundance, sediment depth, canopy height and sediment characteristics were measured to PAGE 12 12 understand correlates with H.

Sediment depth, percent cover abundances of Thalassia testudinum, total macroalgae and sediment chlorophyll a were significant drivers of their distribution. Furthermore, potential food sources for higher trophic predators, such as sea turtles, and seagras s health, which has already been declining in the Florida Bay, will be negatively impacted with overharvesting.

Each species has special i zed shapes and s izes to their ossicles, which are used in taxonomic determinat ion at the species level and to identify juveniles with phenotypic traits that differ from the ir adult counterparts Massin ; Michonneau et al. Previous assessments have relied on ossicle examination as the primary means of species verification and differentiation However, DNA e.

Regardless many species within the Indo Pacific show different color patterns yet have little to no change in their COI sequences Michonneau et al. Fu rthermore, holothurians show morphological adaptations and live in a variety of habitats including tropica l intertidal zones, hard bottom, seagrass bed s, and deep sea bathyal continental slopes Hamel and Mercier ; Toral Grande ; Toral Grande et al.

Thus ossicle and genetic examination are critical in determining species relationships Few studies have focused on trophic position in holothurians. Although, predator prey relationships were examined in literature review by Francour which documented 76 predators on all holothurians including 26 species of fish, 19 species of sea stars, and 17 specie s of crustaceans as the most important.

Many stu dies have set out to determine predatory species, but a few have shown that it is difficult to disce rn if the predation events are sc avenging, or induced through starvation Bourjon and Vasquez Seastar s represent the main predators PAGE 14 14 of holothurians, followed by several fish species. In response to predation holothurians have adap ted defensive mechanisms which include toxicity Bakus ; Bingham and Braithwait ; Castillo ; Van Dyck et al.

J uvenile holo thurians have also been documented to remain cryptic in their behavior possibly as a predator avoidance mechanism Slater et al. A study by So et al. A similar combination of predation and fishing pressure is seen in Parastichopus californicus, which are fished commercially and preyed upon by the sea otter, Enhydra lutris.

Eff ects of H olothurian F oraging on Sediment C haracteristics Holothuria atra and Stichopus chloronotus both commercially important tropical holothurians forage on sediment in the Great Barrier Reef of Australia Uthicke Their bioturbation disturbs th e sediment, which promotes aeration and stratification of the interstitial dissolved organic matter Massin ; Uthicke As the sediment passe s through the gut passage nutrients are regenerated.

Ultimately, H. Alternatively, H. Moriarty et al. Similarly, a study by Michio et al. Alternatively, a n increase in total alkalinity can occur as the holothurian digests the organic matter within the sediment, which ultimately disso lves CaCO 3 and can buffer changes in seawater pH Sc hneider et al.

Similar f eeding strategies have been observed in holothurians inhabiting seagrass beds Wolkenhauer et al. One such tropical holothurian, H. W hen H. Algae is superior in nutrient uptake to seagrass and can pose a threat by intercepting light and blocking diffusion of carbon and oxy gen through the seagrass blades Sand Jensen ; Sand Jensen et al.

M icroalgal biomass can be reduced by C. H olothurians in Banco Chinchorro, Mexico prefer waters with low flow and a high organic sediment accumulation, and were consistently found in seag rass habitats Fuente Betancourt et al.

Alternatively H. These two commercially valuable holothurians are within the same genus and play similar roles in nutrient recycling, but are found in different habitats where the organic content varies These distributional patterns have also been documented in different lifestages within a single species. J uvenile Australostichopus molli s are found in extreme abund ances within sediments characterized as having high nitrogen content, a high pheopigment:chlorophyll a ratio and small grain size as opposed to their adult coun terpart that inhabit sites with higher chlorophyll a content, coarser grain sizes and lower tot al organic content Slater et al.

H olothurians are found throughout Florida, USA, but there is little information on their ecological or distributional patterns Florida is a peninsula with the most southern tip consisting o f a tropical chai n of islands, the Florida Keys This chain of islands is surrounded by the Atlantic Ocean on the southern side, and the Gulf of Mexico and Fl orida Bay on the northern side Figure 1 1.

The upper and middle Keys are comprised of Key Largo limestone whereas the lower Keys are separated with na rrow channels and finger banks characterized by oolitic Miami limestone Hoffmeister The har d bottom habitats are comprised of sponges, octocorals and scleractinian corals with red, green and brown macroalgae interspersed within, housing organisms such as spiny lobsters, stone crabs, turban snails and holothurians Behringer and Butler Alt ernatively, the seagrass habitats are characterized by deep sediments and rooted vascular plants such as Thalassia testudinum, Halodule wrightii, and Syringodium filiforme Zieman et al.

Multiple specie s of holothurians span the east and west coast s of Florida, but here I focus on Holothuria floridana which is found within seagrass and hard bottom habitats, in th e middle and lower Florida Keys Marine Ornamental Fisheries The global trade of marine orn amental species, including reef fish and invertebrates has al.

Currently, more than 45 countries supply reef fish and invertebrates for the aquarium trade, w hich includes over species globally Wood ; Rhyne et al. A shift to miniature reef ecosystem tanks has increased the need for multiple niche satisfying invertebrates such as shrimp, crabs, starfish, snails and holothurians It has been esti mated that about , households in the USA alone have marine aquaria and about 1.

I nvertebrates are not only suffering an increase in demand in th e ornamental aquaria trade, but many are simultaneously fished for food, as are holothurians Rhyne et al. Holothurians feed upon detritus and algae within home aquaria but are also highly sought after within the Asian food industry where the dried body wall is a high protein delicacy, know as b che de mer Conand ; Wolkenhauer et al.

Malaysian processing plants also commercially produce gamat oil from sea cucumber by products thought to be a home PAGE 18 18 remedy for ailments Baine and Choo Poh Sze ; Conand I ncreasing market demands pair ed with unregulated fisheries increases the possibility of fishery collapse Purcell A n increase in e xploited holothurian species has persistently occurred where 40 species were under harvest in Conand , 47 species two years later Tora l Granda et al.

The Western Central Pacific has been experiencing high rates of holothurian overexploitation in boom and bust export prices and demand from Asian countries have steadily increased Kinch et al. Recently, overharves ting has reached the Caribbean where not much is known about the biology or ecology of the species in the trade Toral Grande In some countries, economically important fisheries such as the queen conch Strombus gigas and the spiny lobster Panulirus argus have been overexploited, pushing interest toward holothurians as an economic resource Fuente Betancourt et al.

In Florida, landings quadrupled from to 4 FWC In response the Florida Fish and Wildlife Conservation Commission set a commercial harvest limit of holothurians per day and now require identification of landed species This multi specific holothurian fishery is mainly in the Florida K eys with few landings in other areas of the state. However, Holothuria floridana is the most abundant and targeted more often than other species. Co mpared to other holothurians not much is known about this species, other than a few studies pertaining to their growth and reproductive cycles Edwards ; Edwards ; Engstrom There is a fundamental lack of ecological knowledge about how they affect the areas they forage in, their trophic importance and what drives their distribution As sustaina ble management tends to be a reactionary discipline this knowledge will provide critical proactive information PAGE 19 19 Figure 1 1.

The study are a in the Florida Keys is interspersed with seagrass and hard bottom habitats throughout the Florida B ay and westerly towards the GOM Black ovals denote all study sites per each objective. S ponges, octocorals, scleractinian corals, and patches of red, green, and brown macroalgae are the sessile fauna overlaying the limestone bedrock, that create the 3 dimensional structure of hard bottom habitats Hoffmeister ; Behringer and Butl er Small H.

The latter do not show different col or morphologies or cryptic behavioral traits While the former are fished for the aquarium trade the latter are fished for food The cryptic hiding behavior of the small morph has been seen in other species of holothurians Hamel and Mercier ; Mercier e t al. P redation pressure may drive the morphology and behavior of H. Seagrass beds and hard bottom habitats intersperse throughout Florida B ay and westerly towards the GOM ; seagrass beds are characterized as having deep sediments and rooted vascular plants that contribute a substantial portion of organic carbon to the tro phic web Behringer and PAGE 21 21 Butler Seagrass beds are also crucia l in providing a habitat for juvenile fish a foraging ground for many large fish and invertebrates protect coastlines from erosion and are important in nutrient recycling Grech et al.

Prior work has shown that H. They reduce the amount of benthic microalgae and total organic content within the sediment Wolkenhauer et al. H floridana inhabit similar foraging habit at s as H. The objective of this chapter was to understand the trophic importance of H. To answer these questions I address the following objectives. Methods Objective 1: Ossicle and R eproductiv e Comparison between Hard bottom and Seagrass M orphologies of Holothuria flori dana The ossicles of holothurians are unique to each species Massin et al.

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Florida sea cucumber

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The Florida sea cucumber Holothuria floridana , is a species of marine invertebrate in the family Holothuriidae. It is found on the seabed just below the low tide mark in Florida , the Gulf of Mexico , the Bahamas and the Caribbean. It has an elongated cylindrical shape with a tough, leathery skin with blunt conical protuberances. On the underside it has several rows of short tube feet.

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