Geometric morphometrics, scute patterns and biometrics of loggerhead turtles (Caretta caretta) in the central Mediterranean

We investigate for the first time allometric vs. non-allometric shape variation in sea turtles through a geometric morphometrics approach. Five body parts (carapace, plastron, top and lateral sides of the head, dorsal side of front flippers) were considered in a sample of 58 loggerhead turtles (Caretta caretta) collected in the waters around Lampedusa island, Italy, the central Mediterranean. The allometric component was moderate but significant, except for the plastron, and may represent an ontogenetic optimization in the case of the head and flippers. The predominant non-allometric component encourages further investigation with sex and origin as potential explanatory variables. We also reported the variation of marginal and prefrontal scutes of 1497 turtles, showing that: variation of marginals is mostly limited to the two anteriormost scutes, symmetry is favored, asymmetry is biased to one pattern, and the variation of marginal and prefrontal scutes are linked. Comparisons with other datasets from the Mediterranean show a high variability, more likely caused by epigenetic factors. Finally, conversion equations between the most commonly used biometrics (curved and straight carapace length, carapace width, and weight) are often needed in sea turtle research but are lacking for the Mediterranean and are here estimated from a sample of 2624 turtles.

Download Full-text

Barnacles (Cirripedia, Thoracica) and associated epibionts from sea turtles in the central Mediterranean

Crustaceana ◽

10.1163/156854012x634393 ◽

2012 ◽

Vol 85 (4-5) ◽

pp. 533-549 ◽

Cited By ~ 10

Author(s):

P. Casale ◽

M. D’Addario ◽

D. Freggi ◽

R. Argano

Keyword(s):

Sea Turtles ◽

Caretta Caretta ◽

Sea Turtle ◽

Pioneer Species ◽

Body Parts ◽

Central Mediterranean ◽

Benthic Habitats ◽

Loggerhead Sea Turtles ◽

Juvenile Mortality ◽

Host Habitat

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.

Download Full-text

Cucullanus carettae Baylis, 1923, in a loggerhead sea turtle (Caretta caretta) from the Adriatic sea: first detection and molecular characterization

Parasitology Research ◽

10.1007/s00436-020-06936-5 ◽

2020 ◽

Author(s):

L. Di Renzo ◽

L. Di Gialleonardo ◽

E. Marchiori ◽

G. Di Francesco ◽

V. Curini ◽

...

Keyword(s):

Molecular Characterization ◽

Adriatic Sea ◽

Loggerhead Turtle ◽

Caretta Caretta ◽

Sea Turtle ◽

Loggerhead Sea Turtle ◽

Coprological Examination ◽

Loggerhead Turtles ◽

Bio Monitoring ◽

The Mediterranean

Abstract Cucullanus carettae Baylis, 1923 (Nematoda: Cucullanidae) is found worldwide in loggerhead turtles (Caretta caretta). Regarding the Mediterranean, C. carettae has been identified in the Tyrrhenian and the Ionian Sea and a unique description of a Cucullanus sp. specimen in loggerheads from the Adriatic Sea has been reported in the literature so far. In the framework of a bio-monitoring project of the Abruzzo and Molise coasts, a parasitological survey was performed on stranded and by-caught sea turtles, at the Istituto Zooprofilattico of Abruzzo and Molise “G. Caporale.” During necropsy, the gastrointestinal system of 72 stranded loggerhead turtles was analyzed for the presence of endoparasites and fecal samples were collected for coprological examination. Adult C. carettae (n = 123) was found in the upper intestine of one loggerhead turtle, associated with chronic lymphoplasmocytic enteritis. Additionally, five stool samples (6.9%) were positive for Cucullanus sp. eggs. Molecular characterization of adult nematodes was carried out to study phylogenetic relationships among the Cucullanus species. To our knowledge, this is the first morphological and molecular identification of C. carettae in loggerhead turtles from the Adriatic Sea. Additional studies on the distribution of this parasite in the Mediterranean are encouraged.

Download Full-text

Is the Spanish coast within the regular nesting range of the Mediterranean loggerhead sea turtle (Caretta caretta)?

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315408001768 ◽

2008 ◽

Vol 88 (7) ◽

pp. 1509-1512 ◽

Cited By ~ 8

Author(s):

Jesús Tomás ◽

Manel Gazo ◽

Carla Álvarez ◽

Patricia Gozalbes ◽

Diana Perdiguero ◽

...

Keyword(s):

Mediterranean Sea ◽

Caretta Caretta ◽

Sea Turtle ◽

Mediterranean Coast ◽

Loggerhead Sea Turtle ◽

Spanish Coast ◽

North Eastern ◽

The Mediterranean

We report the information on loggerhead sea turtle (Caretta caretta) nesting events which occurred on the Spanish Mediterranean coast in 2006. Two clutches of 78 and 82 eggs were discovered in the provinces of Valencia (eastern Spain) and Barcelona (north-eastern Spain). We discuss the increasing number of reports of sea turtle nests in Spain within the context of the nesting range of this species in the Mediterranean Sea.

Download Full-text

Movements, Behaviors and Threats to Loggerhead Turtles (Caretta caretta) in the Mediterranean Sea

10.17918/etd-4379 ◽

2021 ◽

Author(s):

Samir Harshad Patel

Keyword(s):

Mediterranean Sea ◽

Caretta Caretta ◽

Loggerhead Turtles ◽

The Mediterranean

Download Full-text

By-catch frequency and size differentiation in loggerhead turtles as a function of surface longline gear type in the western Mediterranean Sea

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315412001841 ◽

2013 ◽

Vol 93 (5) ◽

pp. 1423-1427 ◽

Cited By ~ 11

Author(s):

José Carlos Báez ◽

David Macías ◽

Juan Antonio Camiñas ◽

José María Ortiz de Urbina ◽

Salvador García-Barcelona ◽

...

Keyword(s):

Mediterranean Sea ◽

Sea Turtle ◽

Western Mediterranean ◽

Catch Per Unit Effort ◽

Size Selectivity ◽

Loggerhead Turtles ◽

The Mediterranean ◽

By Catch ◽

Catch Rates ◽

The Impact

Fisheries by-catch is considered to be a major threat to loggerhead turtles in the Mediterranean Sea. Technical differences in both gear configurations (e.g. hook and bait type) and fisheries operations carried out by the Spanish Mediterranean surface longline fleet could have an effect on by-catch rates and size selectivity. The aim of the present study was to test the differences in by-catch per unit effort and body size of loggerhead sea turtles caught using different gear types in the Mediterranean surface longline fishery. Our results suggest that differences in the gear type used have an effect on catch rates and size selectivity. Thus, surface longliners targeting albacore (LLALB) using smaller hooks tend to capture smaller loggerheads but have the highest by-catch per unit of effort (BPUE), whereas other longlines, such as surface longliners targeting bluefin tuna (LLJAP) and traditional surface longliners targeting swordfish (LLHB), using larger hooks tend to select the larger animals; moreover, LLHB had the lowest BPUE. Disproportionate rates of fisheries-induced mortality on certain size/age-classes can differentially affect sea turtle populations, as each sea turtle age-class contributes differently to current and future reproduction. Thus, fisheries management should not only be focusing on preserving the large juvenile and mature turtles, but also on reducing the total by-catch. Thus, we recommend encouraging the use of LLHB versus other surface gears. We suggest that it is very important to take into account the gear type (and its particular catch rates) when making inferences about the impact of longline fisheries on sea turtle populations.

Download Full-text

The genetic structure of the loggerhead sea turtle (Caretta caretta) in the Mediterranean as revealed by nuclear and mitochondrial DNA and its conservation implications

Conservation Genetics ◽

10.1007/s10592-006-9224-8 ◽

2006 ◽

Vol 8 (4) ◽

pp. 761-775 ◽

Cited By ~ 72

Author(s):

C. Carreras ◽

M. Pascual ◽

L. Cardona ◽

A. Aguilar ◽

D. Margaritoulis ◽

...

Keyword(s):

Mitochondrial Dna ◽

Genetic Structure ◽

Caretta Caretta ◽

Sea Turtle ◽

Loggerhead Sea Turtle ◽

Conservation Implications ◽

The Mediterranean

Download Full-text

Allometry, condition factor and growth of the swimming blue crab Portunus segnis in the Gulf of Gabes, Southeastern Tunisia (Central Mediterranean)

Mediterranean Marine Science ◽

10.12681/mms.14515 ◽

2019 ◽

Vol 20 (3) ◽

pp. 566

Author(s):

OLFA BEN ABDALLAH-BEN HADJ HAMIDA ◽

NADER BEN HADJ HAMIDA ◽

HOUDA CHAOUCH ◽

HECHMI MISSAOUI

Keyword(s):

Carapace Length ◽

Condition Factor ◽

Growth Parameters ◽

Carapace Width ◽

Central Mediterranean ◽

Gulf Of Gabes ◽

Gulf Of Gabès ◽

Significant Difference ◽

The Mediterranean ◽

Portunus Segnis

The blue swimming crab Portunus segnis (Forskål, 1775) is one of the earliest Lessepsian invaders of the Mediterranean Sea, and is recorded since decades in various areas of the Mediterranean. Its presence in the southeastern Tunisian coasts (Gulf of Gabes) is, however, very recent. Allometry, condition factor and growth of P. segnis were studied along the Gulf of Gabes coasts. Sampling was performed by artisanal fishing gears as well as trawl net during a one-year period (October 2015 to September 2016) as processed 4971 crabs were collected. The crab carapace width (CW) ranged from 45 to 168 mm for males and 50 to 159 mm for females. The crab carapace length (CL) was 22.02-89.20 mm and 38.70-85.28 mm, respectively for males and females. The carapace width-carapace length, carapace width- front, carapace width-carapace height and carapace width-weight relationships were studied in separate sexes of crab. The covariance analysis indicates a significant difference between the two sexes with respect to the carapace width-carapace length and the carapace width-weight relationships. The condition factor ranged between 0.0042 and 0.0118 with a mean of 0.0078. The condition factor decreased with increasing crab size. The Von Bertalanffy growth parameters CW∞, K and t0 were estimated on the basis of Length-frequency modal progression analysis methods. The mean values of L∞ (mm), K (year-1) and t0 would be, respectively, 206.48 mm, 1.34 and -0.130 for males; 183.89 mm, 1.42 and -0.127 for females and, 190.60 mm, 1.02 and -0.177 for combined sexes.

Download Full-text

The conservation of loggerhead turtles in Zakynthos, Greece

Oryx ◽

10.1017/s0030605300034529 ◽

1990 ◽

Vol 24 (1) ◽

pp. 15-22 ◽

Cited By ~ 3

Author(s):

Lynda M. Warren ◽

Eleni Antonopoulou

Keyword(s):

Prime Factor ◽

Caretta Caretta ◽

Local Economy ◽

Tourist Industry ◽

Human Interference ◽

Conservation Measures ◽

Loggerhead Turtles ◽

The Mediterranean

The population of loggerhead turtles Caretta caretta nesting on the island of Zakynthos, Greece, the largest known rookery in the Mediterranean, is in danger of dying out because of the effects of human interference. Tourism is a prime factor in causing problems, which include direct disturbance of nesting females, compaction of the sand and obstruction of access, photic pollution affecting the hatchlings and accidental damage to adults from speed boats. Attempts are being made to conserve the turtles, and a recent Ministerial Decision should be of help, but implementation of conservation measures is difficult to achieve. This is because the local economy is highly dependent on the tourist industry and there is an understandable reluctance to see this curtailed in any way just to protect the turtles.

Download Full-text