Marine Turtle Newsletter - Seaturtle.org

Marine Turtle Newsletter Issue Number 141

April 2014

High density loggerhead nesting beach on Dirk Hartog Island, Western Australia (see pages 9-12). Photo credit: Linda Reinhold

Articles Sea Turtle Occurrence in Baixada Santista, São Paulo, Brazil............................................................ACV Bondioli et al. Notes on Sea Turtles from the Netherlands: an Overview 1707-2013.........................................................E Goverse et al. Evidence of Leatherback Nesting Activity in Northern Bahia, Brazil.....................................................MD Gandu et al. High-density Loggerhead Sea Turtle Nesting on Dirk Hartog Island, Western Australia..........L Reinhold & A Whiting Mercury Concentration in Tissues of a Captive Green Turtle (Chelonia mydas L.)..............................MF Bezerra et al. Turtles Tagged in Developmental Habitat in Bermuda Nest in Mexico and Costa Rica............................A Meylan et al. Book Reviews Recent Publications

Marine Turtle Newsletter No. 141, 2014 - Page 1

ISSN 0839-7708

Editors:

Managing Editor:

Kelly R. Stewart The Ocean Foundation c/o Marine Mammal and Turtle Division Southwest Fisheries Science Center, NOAA-NMFS 8901 La Jolla Shores Dr. La Jolla, California 92037 USA E-mail: [email protected] Fax: +1 858-546-7003

Matthew H. Godfrey NC Sea Turtle Project NC Wildlife Resources Commission 1507 Ann St. Beaufort, NC 28516 USA E-mail: [email protected]

Michael S. Coyne SEATURTLE.ORG 1 Southampton Place Durham, NC 27705, USA E-mail: [email protected] Fax: +1 919 684-8741

Founding Editor:

Editorial Assistant:

On-line Assistant:

Nicholas Mrosovsky University of Toronto, Canada

Natalie C. Williams University of Florida, USA

ALan F. Rees University of Exeter in Cornwall, UK

Editorial Board: Brendan J. Godley & Annette C. Broderick (Editors Emeriti) University of Exeter in Cornwall, UK

Nicolas J. Pilcher Marine Research Foundation, Malaysia

George H. Balazs National Marine Fisheries Service, Hawaii, USA

Manjula Tiwari National Marine Fisheries Service, La Jolla, USA

Alan B. Bolten University of Florida, USA

ALan F. Rees University of Exeter in Cornwall, UK

Robert P. van Dam Chelonia, Inc. Puerto Rico, USA

Kartik Shanker Indian Institute of Science, Bangalore, India

Angela Formia University of Florence, Italy

Oğuz Türkozan Adnan Menderes University, Turkey

Colin Limpus Queensland Turtle Research Project, Australia

Jeanette Wyneken Florida Atlantic University, USA

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The MTN-Online is produced and managed by ALan Rees and Michael Coyne. Marine Turtle Newsletter No. 141, 2014 - Page 1

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Sea Turtle Occurrence in Baixada Santista, São Paulo, Brazil Ana Cristina Vigliar Bondioli, Amanda Fernandes & Maila Paisano Guilhon e Sá

Instituto Biodiversidade Austral, IBA, São Paulo, SP 013007-001 Brazil (E-mail: [email protected])

Five sea turtles species occur in Brazil, and regularly monitoring occurs at the primary nesting and foraging areas along the coast (Marcovaldi & Marcovaldi 1999). Other coastal areas that are less frequented by sea turtles are not as well monitored. For example, in Baixada Santista, on the central coast of São Paulo state, direct in-water observations (Sazima & Sazima 1983; Luchetta & Bondioli 2009) and records of stranded turtles (Maranho 2008) indicate that these animals visit the region, but there has not been regularly monitoring there. Baixada Santista encompasses the municipalities of Santos, São Vicente, Cubatão, Praia Grande, Mongaguá, Itanhaém, Peruíbe, Guarujá and Bertioga (Fig. 1). It suffers from a host of environmental problems, mainly due to the large concentration of human inhabitants, and ongoing industrial development, including natural resource extraction and port expansion (Silva 2010). In association with this is the issue of increased pollution and marine debris, which poses a threat to marine animals that, occur in this region (Tourinho et al. 2010, Schuyler et al. 2012). To better understand the diversity and relative occurrence of different sea turtle species in the region, we monitored the coast for reported stranded turtles from June 2010 to June 2011. We were alerted to stranded turtles through calls from concerned citizens or authorities such as IBAMA and the fire department. In each case, we collected photos and biometric data according to the method adopted by TAMAR-ICMBio, and in cases of dead animals, we necropsied the animal following Wyneken (2001). We responded to 65 stranded sea turtles in the study area. Of these records, 52 animals were found dead and 13 were still alive, but subsequently died. Three species were recorded: Chelonia mydas, Caretta caretta and Eretmochelys imbricata. All of 65 individuals were all classified as juveniles and subadults (Bjorndal et al. 1994; Moreira et al. 1994, Balptistotte et. al. 2003, Table 1). With respect

to the state of decomposition of the animals, 37 turtles were classified as fresh dead, 12 were moderately decomposed and 16 were highly decomposed. The majority of stranded turtles occurred in the winter (June to September, 50.8% of records), while Bugoni et al. (2001), reported that more stranded turtles occurred during the summer months (October to March). The most commonly encountered turtle was the green turtle (Table 1). The Praia Grande municipality had the highest number of strandings (40%), followed by the Guarujá municipality (30.8%), São Vicente (20%), Bertioga (7.7%) and Mongaguá (1.5%). The increased density of strandings in the cities of Praia Grande, Guarujá and São Vicente is probably related to the co-occurrence of the rocky shoreline covered by seaweed that may serve as foraging habitat for green sea turtles. We necropsied 65 animals, of all three species. We found 78.5% of the study animals had anthropogenic waste in their digestive tract (Table 2), including various types of plastic (candy wrappers, bags, plastic cups and other, classified only as plastic or hard plastic), nylon thread and fishing line, balloons, cigarette packages, pieces of wire, pieces of fabric, Styrofoam and kite pieces. The ingestion of solid waste may occur when turtles confuse waste with natural food items or they may accidentally ingest waste together with food (Balazs 1985; Laist 1987). The waste may obstruct the animal’s gastro-intestinal tract, possibly leading to death, or causing sub-lethal effects such as damage to the walls of the gastro-intestinal tract (Bjorndal 1997), reduced nutritional gain (Mccauley & Bjorndal 1999), increased time of food in the digestive system and changes in buoyancy due to accumulation of gas in the intestines (George 1997). Oceanic juveniles are often exposed to marine debris in convergence zones, and most turtle species are exposed in coastal habitats where they feed (Thomas et al. 2002). We found that 62.3% of our study turtles had plastic in them, similar to the rate of 60.5% reported by Bugoni et al. (2001) for sea turtles found in Rio Grande do Sul state at the southern end of the Brazilian coastline. In some cases, we found that one animal had more than one type of plastic in its digestive tract, pointing to widespread occurrence of plastics in the marine environment and its likely negative impacts (Derraik 2002). During necropsies, we identified food items in 20 green turtles, largely seaweeds and mangrove plants, but also some fish and crustaceans. In one loggerhead, we found a remnant of the shell of a mollusc and digested parts of fish in the intestine, typical food items of this species (Bjorndal 1997). The presence of the food items in the digestive tracts

Figure 1. Map of study area in Baixada Santista. Abbreviations indicate municipalities that compose the region. Modified of CEM/Cebrap-Centro de Estudos da Metrópole-2008.


Mean CCL±SD Mean CCW±SD (range) (range) 38.7±7.5 36.1±7.5 58 C. mydas (31.5-67.5) (28-63.5) 39.4±8.5 48.5±13.6 E. imbricata 4 (33.4-36) (32-35.6) 39.5±8.1 37.4±7.7 3 C. caretta (38.5-65) (37-63.7) Table 1. Biometric data (in cm) for stranded turtles found in Baixada Santista, Brazil, from June 2010-June 2011. CCL = curved carapace length, CCW = curved carapace width. Species

n

of these animals indicates that Baixada Santista is a feeding ground in the region, and we suggest conservation measures are needed to protect the habitat and the animals that use it (Bjorndal 1999). The Baixada Santista coastal ecosystem suffers from anthropic impacts upon its fauna and flora, which may have consequences on human health. Some environmental problems include intense industrial, port and domestic effluents placed indiscriminately into rivers and estuaries, as well as deforestation and a lack of zoning laws for careful development in areas along the outskirts of towns (Hortelani et al. 2005). Other human activities such as large-scale fisheries may also cause negative impacts to sea turtles, contributing to an increase in mortality of sea turtle populations. The intensely urbanized beaches in Baixada Santista are subject to large streams of waste, which are eventually deposited in the coastal seaweed banks used by green sea turtles for food. Furthermore, the human presence may cause other damage, such as the collisions of vessels with animals and/or disturbing them on foraging grounds (Short & Wyllie- Echeverria 1996; Hazel et al. 2007). Finally, dense human presence also complicates the recording of stranding, because carcasses are often collected by people to use as ornaments (Campbell 2002). Therefore, it is necessary to conduct an intense awareness and environmental education campaign in the region, with the objectives to improve local sanitary conditions and raise awareness about sea turtles. This in turn would help ensure that stranded sea turtles would be reported quickly to the appropriate authorities, so that they can be salvaged or rehabilitated as needed. Our study indicates the presence of these animals in the region and its use as a feeding area by green turtles. We suggest that the development of an environmental education programs and ongoing monitoring of the beaches in this region are important measures needed to generate a more complete description of the animals found in this area. In-water work with sea turtles in the region may also shed light on their behavior and migrations, may offer more information on population size, using mark-recapture techniques. Acknowledgements. The authors would like to thank the IBAMA (SISBIO 16988-2) and the Fire Department of Santos. BALAZS, G.H. 1985. Impact of ocean debris on marine turtles: entanglement and ingestion. In: Shomura, R.S. & H.O. Yoshida (Eds.). Proceedings of the Workshop on the Fate and Impact of Marine Debris. NOAA Tech Memo NMFS-SWFC-54. pp. 387429. BAPTISTOTTE, C., J.C.A. THOMÉ & K.A. BJORNDAL. 2003. Reproductive biology and conservation status of the loggerhead

Debris Frequency (%) Plastic 62.3 Nylon/Fishing line 16.9 Balloon 7.5 Cigarette package 3.8 Piece of fabric 3.8 Wire 1.9 Styrofoam 1.9 Kite pieces 1.9 Total 100 Table 2. Frequencies for each residue type found in sea turtles’ digestive tracts. sea turtle (Caretta caretta) in Espírito Santo State, Brazil. Chelonian Conservation & Biology 4: 523-529. BJORNDAL, K.A., A.B. BOLTEN & C.J. LAGUEUX. 1994. Ingestion of marine debris by juvenile sea turtles in coastal Florida habitats. Marine Pollution Bulletin 28: 154-158. BJORNDAL, K.A. 1997. Foraging ecology and nutrition of sea turtles. In: Lutz P.L. & J.A. Musick (Eds.). The Biology of Sea Turtles. CRC Press, Boca Raton, Florida. pp. 199-231. BJORNDAL, K.A. 1999. Priorities for research in foraging habitats. In: Eckert K. L., K.A. Bjorndal, F.A. Abreu-Grobois & M. Donnelly (Eds.). Research and Management Techniques for the Conservation of Sea Turtles. IUCN/ SSC Marine Turtle Specialist Group Publication 4. pp. 12-18. BUGONI, L., L. KRAUSE & M. VIRGÍNIA PETRY. 2001. Marine debris and human impacts on sea turtles in southern Brazil. Marine Pollution Bulletin 42: 1330-1334. CAMPBELL, L.M. 2003. Contemporary culture, use, and conservation of sea turtles. In Lutz P.L., J.A. Musick & J. Wyneken (Eds.). The Biology of Sea Turtles Vol II. CRC Press, Boca Raton, Florida. pp. 301-332. DERRAIK, J.G.B. 2002. The pollution of the marine environment by plastic debris: a review. Marine Pollution Bulletin. 44: 842-852. DIEGUES, A.C. 2002. Povos e Águas: inventário de áreas úmidas brasileiras, 2ª Edição - São Paulo: NUPAUB-USP. GEORGE, R.H. 1997. Health problems & diseases of sea turtles. In: Lutz, P.L. & J.A. Musick (Eds.). The Biology of Sea Turtles. CRC Press, Boca Raton, Florida. pp. 363–387. HAZEL, J., I.R. LAWLER, H. MARSH & S. ROBSON. 2007. Vessel speed increases collision risk for the green turtle Chelonia mydas. Endangered Species Research 3: 105-113. HORTELLANI, M.A., J.E.S. SARKIS, J. BONETTI & C. BONETTI. 2005. Evaluation of mercury contamination in sediments from Santos - São Vicente Estuarine System, São Paulo State, Brazil. Journal of Brazilian Chemical Society 16: 1140-1149. LAIST, D.W. 1987. Overview of the biological effects of lost and discarded plastic debris in the marine environment. Marine Pollution Bulletin 18: 319-326. LUCHETTA, A.C.C.B. & A.C.V. BONDIOLI. 2009. Observação


de tartarugas marinhas em áreas de alimentação. In: V Reunión de Red ASO Tortugas, 2009, Mar del Plata. V Reunión de Red ASO Tortugas - Libro de Resumenes, 2009. MARANHO, A., M.A.M. ATHAYDE, M.C. MENDES, N.S.H.K. CARRIL & F.I. OBERG. 2008. Identificação e quantificação do encalhe de tartarugas marinhas na Baixada Santista, Estado de São Paulo no período 2007-2008. In: 11° Simpósio de Biologia Marinha 30 à 4 de Julho de 2008. Livro de Resumos, Santos, 130-131. MARCOVALDI, M.A. & G.G. MARCOVALDI. 1999. Marine turtles of Brazil: the history and structure of Projeto TAMARIBAMA. Biological Conservation 91: 35-41. MCCAULEY, S.J. & K.A. BJORNDAL. 1999. Conservation implications of dietary dilution from debris ingestion: sublethal effects in post-hatchling loggerhead sea turtles. Conservation Biology 13: 925-929. MOREIRA, L., C. BAPTISTOTTE, J. SCALFONE, J.C. THOMÉ, J.C. & A.P.L.S. DE ALMEIDA. 1995. Occurrence of Chelonia mydas on the Island of Trindade, Brazil. Marine Turtle Newsletter 70: 2.

SAZIMA, I. & M. SAZIMA. 1983. Aspectos de comportamento alimentar e dieta da tartaruga marinhas Chelonia mydas no litoral norte paulista. Boletim do Instituto Oceanográfico. 32: 199-203. SHORT, F.T. & S.WYLLIE-ECHEVERRIA, S. 1996. Natural and human-induced disturbance of seagrasses. Environmental Conservation 23: 17-27. SCHUYLER, Q., B.D. HARDESTY, C. WILCOX & K. TOWNSEND. 2012. To eat or not to eat? Debris selectivity by marine turtles. PloS One 7(7): e40884. SILVA, C.A.M. 2010. Riscos Ambientais em zonas costeiras da Baixada Santista. In: XVII Encontro Nacional de Estudos Populacionais, realizado em Caxambu- MG, Brasil. pp. 1-23. TOMÁS, J., R. GUITART, R. MATEO & J.A. RAGA. 2002. Marine debris ingestion in loggerhead sea turtles, Caretta caretta, from the Western Mediterranean. Marine Pollution Bulletin 44: 211–216. TOURINHO, P.S., J. IVAR DO SUL & G. FILLMAN. 2010. Is marine debris ingestion still a problem for the coastal marine biota of southern Brazil? Marine Pollution Bulletin 60: 396-401. WYNEKEN, J. 2001. Guide to the Anatomy of Sea Turtles. NMFS Tech Memo NMFS-SEFSC-470. 172pp.

Notes on Sea Turtles from the Netherlands: An Overview 1707-2013 Edo Goverse1,2, Max Janse3, Henk Zwartepoorte4, Peter McLean5, Pierre Bonnet6, Arthur Oosterbaan6, Maartje Hilterman7 & Esther Dondorp8

Reptile, Amphibian and Fish Conservation Netherlands (RAVON), P.O. box 1413, 6501 BK Nijmegen; 2Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 93501, 1090 EA Amsterdam, the Netherlands (E-mail: e.goverse@ uva.nl); 3Burgers’ Zoo, Antoon van Hooffplein 1, 6816 SH Arnhem, the Netherlands (E-mail: [email protected]); 4Rotterdam Zoo, Blijdorplaan 8, 3041 JG Rotterdam, the Netherlands (E-mail: [email protected]); 5SEA LIFE Scheveningen, Strandweg 13, 2586 JK, the Hague, the Netherlands (E-mail: [email protected]); 6Ecomare, Ruijslaan 92, 1796 AZ De Koog, the Netherlands (E-mail: [email protected]; [email protected]); 7IUCN National Committee of the Netherlands, Plantage Middenlaan 2K, 1018 DD Amsterdam, the Netherlands (E-mail: [email protected]); 8Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, the Netherlands (E-mail: [email protected]) 1

Marine turtles are regularly found along the north-western part of the European Continental Shelf. Leatherback turtles (Dermochelys coriacea) use the area for foraging and are frequently observed (Doyle et al. 2008; Godley et al. 1998). They may occasionally enter the North Sea from the north, passing between Scotland and Norway. They are likely able to find their way out of the North Sea. These leatherback turtles are believed to originate from the Guianas and the Caribbean region. Other species, like the loggerhead turtle (Caretta caretta) and the Kemp’s ridley (Lepidochelys kempii), travel along the North Atlantic Gyre and on occasion individuals pass through the English Channel towards the North Sea. Green turtles (Chelonia mydas) found at the European Continental Shelf have unknown origins. In 1972 Brongersma compiled all marine turtle records for the European North Atlantic Ocean. Although most cases were well documented, Brongersma reconstructed some. Historically, most

marine turtle sightings and strandings have occurred along the coasts of France, Great Britain and Ireland (Gasc et al. 1997). Occasionally, however, sea turtles are observed in Dutch waters or found stranded on Dutch beaches. The Netherlands is located on the North Sea between Belgium and Germany, and borders the United Kingdom at sea. Twenty-one records of four species were reported for the Netherlands between 1707 and 1971. Due to their infrequent appearance, sea turtles did not receive much attention from Dutch herpetologists. However, the latest published atlas on the distribution of amphibians and reptiles in the Netherlands included a chapter on sea turtles (Hoogmoed 2009). In this publication 25 new records from 1972 to 2008 were described and discussed. Subsequently, an additional four records were added to the national database on sea turtles. This article presents an overview of all known sea turtle records in the Netherlands, which are also listed in Table 1 and shown in Fig. 1.


Year

Location

Province

Map ID Cond

Ref

Kemp’s ridley 1954 Scharendijke, Schouwen

Zeeland

29

alive

1

1970 Midsland, Terschelling

Friesland

7

alive

1

2007 IJmuiden

Noord-Holland

19

alive

2

2008 Westenschouwen, Schouwen

Zeeland

30

alive

2, 4

2011

Zuid-Holland

26

alive

6

Monster

Loggerhead turtle 1707 Wijkmeer, Beverwijk (IJmuiden)

Noord-Holland

19

alive

1

1894 Ouddorp, GoereeOverflakkee

Zuid-Holland

28

alive

1

1927 Scheveningen

Zuid-Holland

24

alive

1

1954 Noordwijk

Zuid-Holland

22

dead

1

1959 Noordwijk

Zuid-Holland

22

dead

1

1998 Vlissingen

Zeeland

36

dead

2

2007 Vlieland

Friesland

9

dead

2

2008 Grootte Keeten

Noord-Holland

13

alive

2, 3

Green turtle 1889 Westkapelle, Walcheren

Zeeland

33

dead

1

1889 Westkapelle, Walcheren

Zeeland

33

dead

1

1889 Westkapelle, Walcheren

Zeeland

33

alive

1

1934 Callantsoog

Noord-Holland

14

dead

1

1934 IJmuiden

Noord-Holland

19

dead

1

1934 Katwijk

Zuid-Holland

23

dead

1

1934 Goeree-Overflakkee

Zuid-Holland

28

dead

1

1937 Katwijk

Zuid-Holland

23

dead

1

1952 Petten

Noord-Holland

15

alive

1

1968 Brown Ridge

North Sea

16

plastron 1

1998 Ameland

Friesland

6

plastron 2

34

sighting 1

1961 12.5 nautical miles north Noord-Holland of Texel

8

dead

1

1968 Ameland

Friesland

6

dead

1

1972 Hondsbossche Zeewering, Petten

Noord-Holland

15

dead

2

1973 Oosterschelde

Zeeland

Leatherback 1777 Domburg, Walcheren

Zeeland

31

sighting 2

1973 Bergen aan Zee/Egmond Noord-Holland aan Zee

17

dead

2

1977 Ameland

Friesland

6

alive

2

1977 Monster

Zuid-Holland

26

dead

2

1980 10 nautical miles north of Schiermonnikoog

Groningen

4

sighting 2

1981 35 nautical miles north of Terschelling

Friesland

1

alive, died

2

1983 Langevelderslag, Noordwijk

Zuid-Holland

21

dead

2

Figure 1. Schematic map of the Netherlands with locations of sea turtle strandings and sightings (1707-2013). Chelonia mydas. In 1889, three green turtles were found stranded in the province of Zeeland. Even though one was found alive, it later succumbed to its injuries. These turtles originated from an American ship transporting animals to the Antwerp Zoo in Belgium, and dead or weak turtles were thrown overboard into the river Scheldt (Brongersma 1972). Four more green turtles were found in 1934 and one in 1937. Four of these had inscriptions in the carapace, which suggested they were caught for the commercial turtle meat, leather, and soup industry in Europe (Brongersma 1972). Two plastron parts were found; one in a fishing net at Brown Ridge, North Sea (1968); the other on a beach on the island of Ameland, Friesland (1998; Brongersma 1972). Hoogmoed (2009) suggested that these were the remains of adult green sea turtles thrown overboard in the 1930s during transport to Hamburg. In 1952 a small living green turtle with a curved carapace length (CCL) of 36 cm washed ashore near Petten, Noord-Holland (Brongersma 1972). At that time the European commercial turtle industry was already closed. Caretta caretta. The oldest record of a sea turtle in the Netherlands dates from 02 October 1707. Based on a drawing of this specimen, Brongersma (1961) concluded that it was a loggerhead turtle. The turtle was displayed in a pub in Amsterdam until it died a few days later. Other stranded loggerheads were recorded in 1894, 1927, 1954 and 1959 (Brongersma 1972). Three loggerhead turtle strandings have been recorded more recently. On 05 August 1998, a loggerhead was found at Vlissingen, Zeeland. This turtle was in a late stage of

Table 1 (left panel). All sightings and strandings of marine turtles in the Netherlands. Cond=Condition of turtle at time of observation. Ref=References: 1=Brongersma 1972; 2=Hoogmoed 2009; 3=Goverse et al. 2009a; 4=Goverse et al. 2009b; 5=Goverse et al. 2010; 6=Goverse et al. 2012.


Province

Map ID Cond

1984 3 nautical miles north of Terschelling

Friesland

5

sighting 2

1987 14 nautic mile north of Den Helder

Noord-Holland

10

sighting 2

1987 Wijk aan Zee

Noord-Holland

18

dead

2

1990 Vlissingen

Zeeland

36

dead

2

1992 4 nautical miles west of Westkapelle, Walcheren

Zeeland

32

alive, died

2

1995 20 nautical miles from Schouwen-Duiveland

Zeeland

27

alive, died

2

1997 Terschelling

Friesland

7

sighting 2

1998 Zandvoort

Zuid-Holland

20

dead

2002 35 nautical miles northwest of Vlieland

Friesland

2

sighting 2

2002 47 nautical miles northwest of Texel

Noord-Holland

3

alive, died

2005 Ouddorp, GoereeOverflakkee

Zuid-Holland

28

sighting 2

2009 Huisduinen, Den Helder

Noord-Holland

12

dead

2009 Texel

Noord-Holland

11

sighting 5

2009 23 nautical miles northwest of GoereeOverflakkee

Zuid-Holland

25

dead

5

alive, died

1

Year

Location

Ref

2

2

5

Unidentified hard-shelled turtle 1971 Valkenisse, Walcheren

Zeeland

35

Table 1 continued (from previous page). decomposition, and the head was missing (Hoogmoed 2009). On 02 March 2007, a small, dead loggerhead turtle (CCL 25 cm) washed ashore on a beach on the island of Vlieland, Friesland (Hoogmoed 2009). On 23 October 23 2008, a loggerhead turtle was found stranded at Groote Keeten, Noord-Holland (Goverse et al. 2009a). It was brought to the Seal Rescue Point at Callantsoog. This turtle was immediately sent to the seal and bird rescue center Ecomare, Texel. The turtle was in poor condition, with a relatively fresh wound at the base of the missing right front flipper. In addition, large amounts of gooseneck barnacles were also removed from the hind flippers. Because the rescue center did not have any experience with sea turtles, the turtle was transported on the following day to Burgers' Zoo at Arnhem. The turtle had a CCL of 52 cm with a weight of 15 kg. At the zoo, it was found that both eyes were infected and the turtle floated on the surface at an angle that suggested pneumonia. The turtle was kept in a 3 meters diameter, 50 cm deep basin. Over the next two weeks the water temperature was slowly increased to 25°C. Antibiotics were administered, and after 20 days the turtle could stay at the bottom of the tank. The turtle began to eat after eight days and fed on herring (Clupea harengus), squid, anchovy (Engraulis encrasicolus), whiting (Merlangius merlangus) and moon jellyfish (Aurelia aurita), along with supplemental multivitamins. The turtle weighed 19 kg after 4 weeks. Releasing it back into the North Sea was not an option due to the temperature of the water. Rehabilitated turtles from the United Kingdom are sent to Gran Canaria, Canary

Islands, Spain (Penrose & Gander 2010). In the case of this turtle, it was decided to release the loggerhead from the coast of Portugal (Goverse et al. 2009a). On 22 July 2009, the turtle was sent to Zoomarine Albufeira, Algarve, Portugal, where it was tagged and released successfully 15 miles from the coast on 07 August 2009. Lepidochelys kempii. Brongersma (1972) described the two records of Kemp’s ridleys, occurring in 1954 and 1970. A third stranding was recorded on 13 January 2007 near IJmuiden, NoordHolland. This small turtle (CCL 23.6 cm) was found alive but died soon afterwards. On 21 November 2008, another small, living Kemp’s ridley (CCL 25.0 cm) was found near Westenschouwen, Zeeland (Epperly et al. 2013; Goverse et al. 2009b). It was partly buried in the sand, and the carapace was covered with oil. The turtle was in poor condition and was immediately brought to the Rotterdam Zoo for rehabilitation. At intake, the turtle weighed 2.24 kg, looked very weak, and swam out of balance, suggesting pneumonia. The water temperature was slowly increased from 14°C on the date of arrival to 22°C on 30 November. On 12 December, the turtle started to eat European sprat (Sprattus sprattus), and its weight increased to 2.49 kg. This Kemp’s ridley joined the loggerhead transport of 22 July 2009, to Zoomarine Albufeira, Algarve, Portugal, for rehabilitation. Up until that point the staff of the Rotterdam Zoo had assumed it was a young loggerhead turtle. In Portugal, however, the turtle was identified as a Kemp’s ridley, which caused the release plan to be modified. Kemp’s ridley turtle nesting sites are restricted to a number of beaches along the Gulf of Mexico, and most posthatchlings and immature turtles remain within the Gulf of Mexico. However, some hatchlings and immature turtles journey across the Atlantic Ocean (Plotkin 2007). To date, it is unknown if Kemp’s ridley turtles can return successfully from Europe back to the Gulf of Mexico on their own. In three cases stranded Kemp’s ridleys from Europe were transported overseas to the U.S.A. to be released; one from France (Pritchard 1996), and two from the United Kingdom (pers. com. R. Penrose 2009; Penrose & Gander 2010). Zoomarine Albufeira also decided to transport the Kemp’s ridley to the U.S.A. However, the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 delayed the release by a year. Finally, on 29 November 2011, the Kemp's turtle arrived at Mote Marine Lab in Florida, U.S.A. After a short quarantine period it was released on 27 December 2011 at Lido Beach, Florida. Prior to its release, the turtle’s CCL measured 54.5 cm with a mass of 31 kg (Epperly et al. 2013). On 10 December 2011 another Kemp’s ridley was found (Goverse

Figure 2. The number of natural strandings and sightings (n=40) (excluding the 10 green turtles that were shipped to Europe and thrown overboard).


et al. 2012). This turtle was found stranded alive near the village of Monster, Zuid-Holland. With the help of the animal rescue team, the turtle was immediately brought to SEA LIFE Scheveningen in Zuid-Holland. This turtle had a CCL of 30 cm and weighed 1.85 kg. The turtle was placed in a 24°C tank, and medical care, such as iodine for small carapacial wounds, and antibiotics were given. After a month the turtle began eating. Again, the decision was made to return this Kemp’s ridley to the U.S.A. for release in the Gulf of Mexico. On 01 November 2012, the turtle was transported to Houston, Texas, and further transported to the Animal Rehabilitation Keep (ARK) in Port Aransas, Texas. After acclimatisation the turtle was successfully released in the Gulf of Mexico on 09 November 2012. Both rehabilitated Kemps’ ridleys were equipped with satellite transmitters; their tracks could be viewed via www.seaturtle.org. Dermochelys coriacea. Prior to 1971, only three records of leatherback turtles in the Netherlands are known in the scientific literature (Brongersma 1972). The oldest record dates from 1777. The other two records are from 1961 and 1968 (one sighting and one stranding, respectively). The substantial increase of observations after Brongersma (1972) is striking. For the period between 1972 and 2005, Hoogmoed (2009) documented nineteen new records. This includes seven dead turtles, seven sightings and five live turtles. Of the latter group, four were caught but died soon after and ended up in the collection of zoological museums. In 2009, another three leatherbacks were recorded (Goverse et al. 2010). The first one was found stranded on 20 September 2009, on a beach near Huisduinen, Noord-Holland. The carcass exhibited injuries consistent with a boat propeller but whether this caused the turtle’s death is unknown. A week later a sighting was reported near the shore of the island of Texel. This turtle was observed several times in the same area between 27 September and 18 October 2009. On 07 October 2009, a dead leatherback was taken out of the sea 23 nautical miles northwest of Goeree-Overflakkee, Zuid-Holland. The carcass was handed over to Naturalis Biodiversity Center. Cheloniidae. One unidentified hard-shelled sea turtle was documented by Brongersma (1972). This sea turtle was found alive in 1971 near Valkenisse, Zeeland. The turtle was put in fresh water but died a few days later and was buried to get rid of the smell. Fig. 2 shows all natural strandings and sightings in the Netherlands by decadal increments (n=40). Although there is a recorded increase in observations, the numbers are too small to draw any conclusions. Witt et al. (2007) reported an increasing trend for the number of leatherback turtle sightings and strandings at the European continental shelf. They stated that this trend is likely reflective of increasing awareness and promotion of public reporting schemes for marine vertebrates, but it may, in part, also reflect an increasing number of leatherbacks in the Northern Atlantic (Turtle Expert Working Group 2007). Increased boat traffic may also contribute to the increase in observations. Additionally, factors that could have contributed to increased observations include the number of visitors on beaches, which has increased enormously since the time period covered by Brongersma (1972). Also, the information infrastructure has improved concurrently during this time, so sightings and strandings are more likely to be reported to the relevant institutions and local media. This may explain, at least for the Netherlands, the increased number of leatherback records compared to the period reported by Brongersma (1972); three records before 1972 versus 22 records after 1972.

Figure 3. All natural strandings and sightings presented per month. Two of the 40 documented strandings did not have an associated month recorded (Un=unknown species, Cm=Chelonia mydas, Lk=Lepidochelys kempii, Cc=Caretta caretta, Dc=Dermochelys coriacea). Most strandings and sightings (84%) with a documented month occurred between August and December (Fig. 3). Records of leatherback turtles in the North-eastern Atlantic show a seasonal pattern, increasing during summer and declining during late autumn and winter (Witt et al. 2007). In the Netherlands, 88% (n=24) of the leatherback observations were between August and December. These turtles may have entered the North Sea after leaving their foraging grounds. However, patterns of seasonal occupation inferred from public sightings records must be interpreted with caution as they lack correction for spatial and temporal (seasonal) bias in survey effort (Witt et al. 2007). The numbers of observed hard-shelled turtles are to small to detect a trend. Eleven of the 15 stranded hard-shelled sea turtles were alive when found, but most died soon after finding. Most stranded turtles were very weak, cold-stunned, ill, and/or treated incorrectly. The three latest stranded sea turtles in the Netherlands were fortunate. They were the first successfully rehabilitated sea turtles for the country. As long as sea turtle species are listed on the IUCN Red List of Threatened Species we believe we should make all efforts to save each turtle we can. In absence of a stranding protocol, we took the initiative to develop one (www.ravon.nl). Hopefully this will help increase the chances of survival for any future stranded sea turtles. Acknowledgements. Thanks to all the team members and organisations that were involved in the rehabilitation of the three rehabilitated sea turtles. BRONGERSMA, L.D. 1961. Notes upon some sea turtles. Zoologische Verhandelingen 51: 1-46. BRONGERSMA, L.D. 1972. European Atlantic turtles. Zoologische Verhandelingen 121: 1-318. DOYLE, T.K., J.D.R. HOUGHTON, P.F. O'SUILLEABHAIN, V.J. HOBSON, F. MARNELL, J. DAVENPORT & G.C. HAYS. 2008. Leatherback turtles satellite-tagged in European waters. Endangered Species Research 4: 23-31. EPPERLY, S.P., A. NUNES, H. ZWARTEPOORTE, L. BYRD, M. KOPERSKI, L. STOKES, M. BRAGANÇA, A.D. TUCKER & C.R. SASSO. 2013. Repatriation of a Kemp's Ridley from the Eastern North Atlantic to the Gulf of Mexico. Marine Turtle Newsletter 136: 1-2. GASC, J.P., A. CABELA, J. CRNOBRNJA-ISAILOVIC, D.


DOLMEN, K. GROSSENBACHER, P. HAFFNER, J. LESCURE, H. MARTENS, J.P. MARTÍNEZ RICA, H. MAURIN, M.E. OLIVEIRA, T.S. SOFIANIDOU, M. VEITH & A. ZUIDERWIJK. 1997. Atlas of amphibians and reptiles in Europe. Societas Europaea Herpetologica and Muséum National d’Hostoire Naturelle (IEGB/SPN), Paris. 496pp. GODLEY, B.J., M.J. GAYWOOD, R.J. LAW, C.J. MCCARTHY, C. MCKENZIE, I.A.P. PATTERSON, R.S. PENROSE, R.J. REID & H.M. ROSS. 1998. Patterns of marine turtle mortality in British waters (1992-1996) with reference to tissue contaminant levels. Journal of the Marine Biological Association of the United Kingdom 78: 973-984. GOVERSE, E., J. DRUBBEL & F. GRÜNEWALD. 2012. Nederlandse Kemps zeeschildpadden in het nieuws. RAVON 43 14: 17-19. GOVERSE, E., M.L. HILTERMAN, P. BONNET & R. DE RUITER. 2010. De lederschildpad: spectaculaire nieuwe waarnemingen in Nederland en een statusoverzicht. RAVON 35 12: 5-10. GOVERSE, E., M. HILTERMAN, M. JANSE, A. OOSTERBAAN & H. ZWARTEPOORTE. 2009a. Dikkopschildpad: Een bijzondere dwaalgast in Nederland. RAVON 32 11: 8-12. GOVERSE, E., M.L. HILTERMAN, M. JANSE & H. ZWARTEPOORTE. 2009b. Kemps zeeschildpad: een nòg bijzonderder dwaalgast in Nederland. RAVON 33 11: 38-43.

HOOGMOED, M.S. 2009. Zeeschildpadden. In: Creemers R.C.M. & J.J.C.W. van Delft (Eds.). De Amfibieën en Reptielen van Nederland. Nederlandse Fauna 9. Nationaal Historisch Museum Naturalis, KNNV Uitgeverij, European Invertebrate SurveyNederland. pp. 339-351. PENROSE, R.S. & L.R. GANDER. 2010. British Isles & Republic of Ireland Marine Turtle Strandings & Sightings Annual Report 2009. Marine Environmental Monitoring, Penwalk, Llechryd, Cardigan, Ceredigion, West Wales. 25pp. PLOTKIN, P.T (Ed.). 2007. Biology and conservation of ridley turtles. John Hopkins University Press, Baltimore. 356pp. PRITCHARD, P.C.H. 1996. Kemp's ridley, lost in France, returns to Florida. Florida Naturalist 69: 13, 22. TURTLE EXPERT WORKING GROUP. 2007. An assessment of the leatherback turtle population in the Atlantic Ocean. NOAA Technical Memorandum NMFS-SEFSC-555. 116pp. WITT M.J., A.C. BRODERICK, D.J. JOHNS, C. MARTIN, R. PENROSE, M.S. HOOGMOED & B.J. GODLEY. 2007. Prey landscapes help identify potential foraging habitats for leatherback turtles in the northeast Atlantic. Marine Ecology Progress Series 337: 231-243.

High-density Loggerhead Sea Turtle Nesting on Dirk Hartog Island, Western Australia Linda Reinhold1 & Andrea Whiting2

Department of Parks and Wildlife, 61 Knight Terrace, Denham WA 6537, Australia (E-mail: [email protected]) 2 PO Box 1212, Bentley DC, WA 6983, Australia (E-mail: [email protected])

1

The Western Australian population of loggerhead turtles, Caretta caretta, is recognized as a single genetic stock (Dutton et al. 2002; FitzSimmons et al. 1996; Limpus 2008). Nesting spans approximately 520 km from Steep Point (southwest of Denham) to the Muiron Islands (northeast of Exmouth) (Baldwin et al. 2003). Dirk Hartog Island is close to the southern end of this range. Nesting loggerheads have been flipper-tagged on Dirk Hartog Island nearly every year since 1993/94 (the 1994/95, 1995/96 and 2006/07 seasons were missed) as part of a mark-recapture program started by the Western Australian Marine Turtle Project, which is part of the Department of Parks and Wildlife (WAMTP, DPaW) (Prince 1994, 2000). Each year the number of peak-season nesting females tagged is counted, but a reliable estimate requires next-day track counts to account for those individuals missed during night surveys. In addition, spatial and temporal tagging effort has differed between years. Although tagged nesting females have been counted, morning surveys have not been conducted. Thus, mark-recapture data was the only way annual nesting numbers could be consistently quantified. The most recently published annual nesting population estimate for Dirk Hartog Island was approximately 1,000 or more individuals, based on late 1990s mark-recapture sample data (Baldwin et al. 2003). However, during some years with trained teams patrolling all beaches (1998, 1999, 2000, 2008) 1,400 turtles were tagged

during each two-week peak period alone (WAMTP unpublished data), indicating annual nesting numbers greater than previously estimated. Remote area logistics constrain the tagging effort to two weeks each season. This pilot study used an alternative approach to estimating the numbers of loggerheads nesting at the peak of each season by using counts of turtle tracks and nesting success. Until a more recent mark-recapture analysis is conducted, this method allows repeatable counts of peak nesting numbers to be compared yearly. This is the first application of track count and nesting success methodology to the Dirk Hartog Island loggerhead sea turtle rookery. Study site. The northern end of Dirk Hartog Island National Park (25°29’S, 112°59’E) is located in the Shark Bay Marine Park and the World Heritage Area. This protected area is an important nesting habitat for the majority of loggerheads from the Western Australian population. The nesting season extends from November into April (Prince 1994), with the peak of the nesting season occurring in midJanuary (Baldwin et al. 2003). Occasional turtle tracks are observed throughout the year (Bob Prince, pers. comm. 2011). Green turtle, Chelonia mydas, tracks have also been occasionally recorded on Dirk Hartog Island (2008/09, 2009/10 and 2011/12). The rookery is composed of five nesting beaches, interspersed with areas of rocky shore (Fig. 1). The nesting habitat used in this study measured 2.1 km in length. This was a normal length of sand


compared with other seasons, but sometimes, whole beaches are stripped of sand during cyclones, building back before the following season. Loggerhead nesting on Dirk Hartog Island is not restricted to these beaches. Other beaches extend south and west of these five survey sites, with southern low-density nesting extending beyond Cape Levillain, as well as intermittently westward around to the lighthouse precinct at Cape Inscription, on other beaches of Dirk Hartog Island and on the mainland to the south of the study site, at Steep Point (Pam Dickenson, pers. comm. 2011). Track counts are defined as the total number of tracks, including both successful and unsuccessful nesting attempts. From 6-18 January 2011, nesting turtle tracks were counted at sunrise each day by foot or quadbike (all-terrain vehicle-ATV) across the five study site beaches. The new tracks were crossed each day either by ATV tire tracks (Beach 5), or by a drag (a looped rope attached to a length of chain spaced by a stick) pulled behind the person counting on foot (Beaches 1, 2, 3 and 4). The lower-density adjacent beaches to the southeast and west were also counted for tracks. This pilot study, of counting daily nesting attempts, ran alongside the annual markrecapture program (Prince 2000). As part of the tagging program during the years before and after this study, turtles were tagged regardless of whether they had finished laying their eggs. This meant that turtles often had to emerge more than once because their first nesting attempt was aborted due to human disturbance, thus biasing any track counts. To obtain natural track counts for the one season of this pilot study, the tagging teams had an added stipulation not to disturb any turtles for tagging unless they had laid their eggs, or were already heading back to the water. Tagging teams also took care not to disturb neighboring turtles. Nesting success varies with beach geomorphology. On Beach 4, turtles often encounter rocks while digging egg chambers. On any of the beaches, turtles also occasionally disturb each other because of the high density of nesting within the study site. For three of the 113°00’E

Cape Inscription

25°20’S

25°29’S

112°59’E

nights during the study period, undisturbed nesting success was quantified over 1.6 km, encompassing 76% of the main nesting beaches. During these three nights, from 19:30 to 05:30, surveyors were assigned a section of beach (ranging from 50 m to 300 m in length) at which to tally the number of turtles coming ashore and designate if a clutch of eggs was laid in each instance. Nesting success was calculated as the proportion of turtles completing successful oviposition divided by the total number coming ashore for each beach section (Limpus et al. 2003). Quantifying nesting success makes track counts meaningful, as the moisture content and depth of sand over beachrock can change seasonally, affecting the proportion of tracks resulting in successful nests. The measurement of undisturbed nesting success may also become a significant parameter for assessing long-term changes in beach quality. The nesting success rate was multiplied by the daily track count (total number of nesting attempts, regardless of whether they laid eggs or not) to give the number of clutches laid on each section of beach per night over the 13-day survey, during mid-season. Several beaches differing in topography, sand texture and rockiness were sampled to more accurately match any resulting differences in nesting success with individual beach track count data. Each clutch laid represents one female. The internesting interval for loggerheads is typically approximately 14 days (Dodd 1988). Density parameters were calculated at mid-season (January) (clutches km-1 night-1) to enable comparison with data gathered at other loggerhead rookeries, including high-density beaches of Masirah Island, Oman (Ross 1998). It was beyond the scope of this pilot study to extrapolate the mid-season data to estimate nesting numbers for the entire season. During the 13-day survey, daily track counts averaged 165 per night (min: 102, max: 253) for the total 2.1 km comprising the five rookery beaches. When the track surveys from the adjacent lowerdensity beaches to the southeast and west were included, average daily track count increased to 193 (min: 121, max: 289 tracks per night, Table 1). To derive an estimate of 113°01’E nesting success, 125 (8%) out of the total 1590 tracks on the five beaches were sampled for successful egg laying. Out of the sample size of 125 turtles, 92 turtles laid and 33 did not lay, giving a nesting success rate of 73.6% for the rookery (Table 1). Loggerhead nesting success was highest (87.5%) at the open sandy stretch of Beach 1, and lowest (30%) on Beach 4. A chi-square test identified significant differences in nesting success between beaches (Beach 1: B4 χ2=22.5, df=1, p=