scholarly journals Meiofauna Life on Loggerhead Sea Turtles-Diversely Structured Abundance and Biodiversity Hotspots That Challenge the Meiofauna Paradox

Diversity ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 203
Author(s):  
Jeroen Ingels ◽  
Yirina Valdes ◽  
Letícia P. Pontes ◽  
Alexsandra C. Silva ◽  
Patrícia F. Neres ◽  
...  

Sea turtles migrate thousands of miles annually between foraging and breeding areas, carrying dozens of epibiont species with them on their journeys. Most sea turtle epibiont studies have focused on large-sized organisms, those visible to the naked eye. Here, we report previously undocumented levels of epibiont abundance and biodiversity for loggerhead sea turtles (Caretta caretta), by focusing on the microscopic meiofauna. During the peak of the 2018 loggerhead nesting season at St. George Island, Florida, USA, we sampled all epibionts from 24 carapaces. From the subsamples, we identified 38,874 meiofauna individuals belonging to 20 higher taxa. This means 810,753 individuals were recovered in our survey, with an average of 33,781 individuals per carapace. Of 6992 identified nematodes, 111 different genera were observed. To our knowledge, such levels of sea turtle epibiont abundance and diversity have never been recorded. Loggerhead carapaces are without doubt hotspots of meiofaunal and nematode diversity, especially compared to other non-sedimentary substrates. The posterior carapace sections harbored higher diversity and evenness compared to the anterior and middle sections, suggesting increased colonization and potentially facilitation favoring posterior carapace epibiosis, or increased disturbance on the anterior and middle carapace sections. Our findings also shed new light on the meiofauna paradox: “How do small, benthic meiofauna organisms become cosmopolitan over large geographic ranges?” Considering high loggerhead epibiont colonization, the large distances loggerheads migrate for reproduction and feeding, and the evolutionary age and sheer numbers of sea turtles worldwide, potentially large-scale exchange and dispersal for meiofauna through phoresis is implied. We distinguished different groups of loggerhead carapaces based on divergent epibiont communities, suggesting distinct epibiont colonization processes. These epibiont observations hold potential for investigating loggerhead movements and, hence, their conservation.

2019 ◽  
Vol 10 (1) ◽  
pp. 163-174
Author(s):  
Jacob A. Lasala ◽  
Colin Hughes ◽  
Jeanette Wyneken

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Frederic Vandeperre ◽  
Hugo Parra ◽  
Christopher K. Pham ◽  
Miguel Machete ◽  
Marco Santos ◽  
...  

Abstract After hatching, juveniles of most sea turtle species undertake long migrations across ocean basins and remain in oceanic habitats for several years. Assessing population abundance and demographic parameters during this oceanic stage is challenging. Two long-recognized deficiencies in population assessment are (i) reliance on trends in numbers of nests or reproductive females at nesting beaches and (ii) ignorance of factors regulating recruitment to the early oceanic stage. To address these critical gaps, we examined 15 years of standardized loggerhead sighting data collected opportunistically by fisheries observers in the Azores archipelago. From 2001 to 2015, 429 loggerheads were sighted during 67,922 km of survey effort. We used a model-based approach to evaluate the influence of environmental factors and present the first estimates of relative abundance of oceanic-stage juvenile sea turtles. During this period, relative abundance of loggerheads in the Azores tracked annual nest abundance at source rookeries in Florida when adjusted for a 3-year lag. This concurrence of abundance patterns indicates that recruitment to the oceanic stage is more dependent on nest abundance at source rookeries than on stochastic processes derived from short term climatic variability, as previously believed.


Author(s):  
J.C. Eiras ◽  
T. Dellinger ◽  
A.J. Davies ◽  
G. Costa ◽  
A.P. Alves de Matos

Intracytoplasmic inclusion bodies were detected in the mature red blood cells of twenty juvenile loggerhead sea turtles, Caretta caretta, captured in Madeira. The bodies were mostly single, round to oval, frequently irregular in outline, and their diameter varied from 0.5 to 2.0 μm. Most bodies were associated with small granular areas, often in the form of a tail or projection. In some cells, only granular areas were apparent. The nuclei of most erythrocytes were irregular in outline but degeneration of red blood cells was not observed. The identity of these intraerythrocytic structures is not clear but they may be viral or rickettsial in nature.


2020 ◽  
Vol 48 (1) ◽  
pp. 146-149
Author(s):  
Helena Fernández-Sanz ◽  
Fabián Castillo Romero ◽  
Joaquín Rivera Rodríguez ◽  
Noé López Paz ◽  
Gabriel Arturo Zaragoza Aguilar ◽  
...  

The loggerhead sea turtle (Caretta caretta) is an endangered species which distributes around the west coast of the Baja California Peninsula. In Baja California Sur, the conservation efforts for this species were focused in the Gulf of Ulloa; however, within the Pacific coast of the Baja California Peninsula, Sebastián Vizcaíno Bay (SVB) biological active center suit the optimal conditions for the presence of loggerheads. This study aimed to investigate SVB as a potential foraging area for loggerheads. Between July and August 2018, three prospective surveys were conducted, in search of marine turtles in SVB. A total of three loggerhead turtles and one eastern Pacific green turtle (Chelonia mydas) were captured; biometric data were recorded, and organisms were classified as juveniles. This is the first report of the loggerhead sea turtles in the SVB and given the oceanographic characteristics of the bay, it is a potential foraging and development area for the species.


Crustaceana ◽  
2012 ◽  
Vol 85 (4-5) ◽  
pp. 533-549 ◽  
Author(s):  
P. Casale ◽  
M. D’Addario ◽  
D. Freggi ◽  
R. Argano

The association patterns and ecology of sea turtle epibionts, and especially obligate epibionts, are still poorly known. Epibiont communities were investigated in the central Mediterranean Sea in relation to the host habitat and seven species of barnacles, three amphipods, one crab, and one tanaid were found on 117 loggerhead sea turtles, Caretta caretta. Particular attention was given to barnacles, some of them being obligate turtle epibionts, with a total of 3330 individuals examined, among which high intraspecific aggregation was observed. Results indicate that (i) the species composition of barnacles varies among turtles frequenting not only different geographic areas but also different habitats in the same area, (ii) different species have marked preferences for hosts frequenting pelagic vs. benthic habitats, and also (iii) for body parts of the host representing microhabitats with different features and trophic opportunities, (iv) settlement is favoured by the presence of conspecific individuals and possibly also (v) by individuals of related species, notably Chelonibia testudinaria that may act as a pioneer species, and finally (vi) barnacles show rapid turnover on turtles, with relatively short lives, rapid growth, and high juvenile mortality.


Author(s):  
José C. Rocha Júnior ◽  
Joseph B. Pfaller ◽  
Ricardo Corbetta ◽  
Luciana Veríssimo

Studies of sea turtle epibiosis have focused on the diversity and ecology of facultative commensalisms and less attention has been given to parasitic associations, in which the epibiont species derives nutrients from the tissue of the host turtle. We present the first description and quantitative survey of the parasitic isopods Excorallana costata, Excorallana bicornis and Excorallana oculata on loggerhead (N = 79) and hawksbill turtles (N = 23), and E. costata on olive ridley turtles (N = 9), nesting on Praia do Forte, Bahia, Brazil during the 2009–2010 season. Excorallana costata was the most common isopod species (N = 651), followed by E. bicornis (N = 77) and E. oculata (N = 20). Patterns include: (1) E. costata exhibited a higher frequency and intensity of parasitism than E. bicornis and E. oculata and (2) loggerheads hosted parasitic isopods at a higher frequency and intensity than hawksbills and olive ridleys. We also detected temporal shifts in the occurrence and intensity of parasitism across the nesting season, which strongly suggests that turtles were parasitized by all three isopod species during their internesting periods. Because parasitic isopods were observed only rarely prior to the 2009–2010 turtle-nesting season and have continued to be common in subsequent seasons, it is important to gain a better understanding of the basic biology of these interactions, the reasons for their recent emergence, and the potential biological impacts on turtle, as well as isopod, populations.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Kimberly Smelker ◽  
Lauren Smith ◽  
Michael Arendt ◽  
Jeffrey Schwenter ◽  
David Rostal ◽  
...  

Vitellogenin is the egg yolk precursor protein produced by oviparous vertebrates. As endogenous estrogen increases during early reproductive activity, hepatic production of vitellogenin is induced and is assumed to be complete in female sea turtles before the first nesting event. Until the present study, innate production of vitellogenin has not been described in free-ranging sea turtles. Our study describes circulating concentrations of vitellogenin in loggerhead sea turtles (Caretta caretta) from the Northwest Atlantic Ocean. We collected blood samples from juveniles and adults via in-water captures off the coast of the Southeast USA from May to August, and from nesting females in June and July at Hutchinson Island, Florida. All samples were analyzed using an in-house ELISA developed specifically to measureCaretta carettavitellogenin concentration. As expected, plasma vitellogenin declined in nesting turtles as the nesting season progressed, although it still remained relatively elevated at the end of the season. In addition, mean vitellogenin concentration in nesting turtles was 1,000 times greater than that measured in samples from in-water captures. Our results suggest that vitellogenesis may continue throughout the nesting season, albeit at a decreasing rate. Further, vitellogenin detected in turtles captured in-water may have resulted from exposure to endocrine disrupting chemicals.


Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1408
Author(s):  
Antonino Gentile ◽  
Tullia Amato ◽  
Andrea Gustinelli ◽  
Maria Letizia Fioravanti ◽  
Delia Gambino ◽  
...  

We provide new data on the presence of helminth parasites in 64 individual loggerhead sea turtles Caretta caretta stranded along the coasts of Sicily and the northwest Adriatic Sea between June 2014 and August 2016. The necropsy examination revealed 31 individuals (48.4%) positive for endoparasites, showing a greater prevalence of trematodes than nematodes. In particular, seven species and a single genus of Trematoda (Hapalotrema) and a single species and genus of Nematoda (Kathlania) were identified. Among the Digenea flukes the species with the highest prevalence of infection were Rhytidodes gelatinosus (34.6%) and Hapalotrema sp. (33.3%), while among the Nematoda they were Kathlania sp. (33.3%) and Sulcascaris sulcata (33.3%). Analysis of variance (ANOVA) was applied among the recovery sites of the stranded loggerhead sea turtles and prevalence of endoparasites was used to highlight any relationship between the parasites and the origin of the hosts. ANOVA showed significant differences (p < 0.001) among the data used.


Zootaxa ◽  
2019 ◽  
Vol 4695 (5) ◽  
pp. 497-500
Author(s):  
RYOTA HAYASHI ◽  
MASANORI OKANISHI

We describe the first occurrence of the widely occurring brittlestar Ophiactis savignyi (Müller & Troschel, 1842) as epibionts on Caretta caretta (Linnaeus, 1758), the loggerhead sea turtles. On the sea turtle epibionts, the coronulid barnacles were well studied as listed in Hayashi (2013), and recently some crustaceans were collected from loggerhead sea turtles and described as new species (Tanabe et al. 2017; Tanaka and Hayashi 2019). In contrast, echinoderm epibionts listed from sea turtles are poorly understood (Table 1) and this study represents the novel discovery of an ophiuroid, which was not previously known to occur on the surface of this species. 


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