Neonate survival en handled broods of the Olive Ridley Turtle Lepidochelys olivacea (Testudines: Cheloniidae) in El Verde, Sinaloa, Mexico

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1 Neonate survival en handled roods of the Olive Ridley Turtle Lepidohelys olivaea (Testudines: Cheloniidae) in El Verde, Sinaloa, Mexio Luis A. Rendón M. and Armando A. Ortega-Salas Instituto de Cienias del Mar y Limnología, UNAM, Joel Montes Camarena s/n, Mazatlán 82, Sinaloa; ortsal@marl.unam.mx Reeived 18-IX-212 Correted 19-XII-212 Aepted 3-I-213 ABSTRACT We worked in the protetive and onservation area of the Olive Ridley Turtle Lepidohelys olivaea in the eahes of Estero Verde, Sinaloa, Mexio (24 season). The position in the eah does not affet survival. We found nests until the preferential nesting site loated at the eginning of the seond sandy erm in a zone free of vegetation; and the latter presented a slight inrease in survival. Speimens handled for 2-5 hours survived less (R 2 =,82). KEY WORDS Inidene of turtles, management, survival, proteted area, onservation. RESUMEN Traajamos en la zona de proteión y onservaión de la tortuga golfina Lepidohelys olivaea en las playas del Estero el Verde, Sinaloa, Méxio, en la temporada 24. La posiión en la playa no afeta la supervivenia. Hallamos nidadas hasta el sitio preferenial de anidaión uiado al iniio de la segunda erma arenosa en zona lire de vegetaión; estas últimas representaron un ligero inremento en la supervivenia. Un manejo de 2 a 5 horas redue la supervivenia (R 2 =,82). PALABRAS CLAVE Inidenia de tortugas, manejo, sorevivenia, zona de proteión, onservaión. The olive ridley turtle Lepidohelys olivaea (Eshsholtz, 1829), is one of the most aundant sea turtles (Limpus, 1995). The atmosphere of the nesting eahes and the environment in the halls of inuation, it is very important to study the iology of reprodution and nesting (Rihardson, 2); therefore, a ontinuous nesting eahes, monitoring as well as also an effetive monitoring, will provide important information for the effetiveness of hathing in the nests is greater. The site on the eah eah gender hoose to nest, seems to e related to the size and the average weight of the animal, turtles of the genus Lepidohelys arrive at Sandy arrier eahes and usually go up until the first erm or terrae, where it is ommon that they nest eahes and usually go up until the first erm or terrae, where it is ommon that they nest together at the first attempt in learanes of vegetation, unless they find an ostale as roots, stones or stiks uried, eause then seek a new site lose to the first, where will try again to dig the nest (Marquez, 1996). In agreement with Limpus, Baker & Milar (1979) and Parmenter (198) all handling (exavation, transportation and re-seeding) should e within two hours of the oviposition of the eggs or eggs should e left in plae at least 25 days to redue the impat of the movement whih leads to mortality. It is important to determine limits of protetion, the areas of highest inidene of nesting turtles, so implement monitoring plans to improve handling of roods tehniques and also that these areas are somewhat etter sheltered, without removing the importane and time zones with lower quantities, sine the entire area represents an important potential in the onservation of this ody. On the other hand would in etter shape luthes exposed to predators or looting. Cuadernos de Investigaión UNED (ISSN: ) Vol. 5(1), Junio,

2 METHODOLOGY El Verde Camaho eah (Fig. 1) is loated 1km approximately to the North of the ity of Mazatlán, Sinaloa on the Mexian Paifi oast. Corresponds to a proteted natural area in the form of reservation and site of refuge area for the protetion, onservation, reforestation, development and Control of the different speies of turtle marine El Verde eah, ,85 N ,92 W and ,48 N ,15 W. Patrols were onduted for the monitoring the area and olletion of nests reorded numer of eggs, time of olletion and time of reseeded luth. Cluth data is laeled and the perentage of hathing or survival of eggs, estalished position, whih orresponds to the preferential nesting site of the turtle, olive ridley on the eah, aording to Marquez (1996). The nesting area was marked y stakes every 15m to have 1 stakes within the overage area. Cluthes were moved to the Protetion Center loated near the area of protetion, re-seeding in polyurethane oxes, and arrangement in an inuation room. Development of the proessing of the data We used Exel and Statistial version 5.1 (StatSoft In., Tulsa, OK). ANOVA was performed to see if there were differenes in survival etween y handling time. The Kruskal-Wallis test was used to determine whether there are differenes in the average of turtles that ome to spawn along the areas of the protetion of El Verde. Later the Student-Newman-Keuls multiple omparison test was used (Montgomery, 1991), an ANOVA was applied to determine differenes in the perentage of survival y area. Quelite River Protetion Center El Verde El Verde Estuary Mazatlán City Gulf of California Protetion and Conservation Area ,5 1 1:1 km FIG. 1. Zone of the sea turtle protetion L. olivaea, El Verde. 138 Researh Journal of the Costa Rian Distane Eduation University (ISSN: ) Vol. 5(1), June, 213

3 The data proessing was done in the Instituto de Cienias del Mar y Limnología de la UNAM. RESULTS A susample of the olleted roods omprising from May 28 to 13 of Septemer 24, whih is the time of greatest aundane of luthes (Fig. 2) was used for this study. The preferred nesting site of the turtle, olive Ridley on the eah (Fig. 3) was estalished and its effet on survival in neonates was analyzed; Tale 1 shows the numer of eggs, neonates living and survival perentage results. Numer of nest Apr. Sep. Fe. Jul. De Time FIG. 2. Numer of nests in the time series representative of the site. Survival was not affeted y position (ANOVA p=,1624, Fig. 4). The numer of roods found y position indiates that there is a preferene in nesting in positions 3 and 4, while position 6 seemed to e avoided (Fig. 5). The numer of eggs remains onstant, ut the perentage of survival had a slight inrease in position 6. We ategorized four groups of handling time: to,5,,5 to 1, 1 to 2 and 2 to 5 hours, that speifies timeout handling of luthes. With longer handling of the luth (olletion, transport and reseeded luth), there is a derease in the perentage hathing; F (3,31)=4,3289, p=,52. The 2 to 5 hour period was the worst (Tukey). The mean numer of turtles varied with setions of the eah (Kruskall-Wallis ANOVA, Fig. 6). Zone 1 (,25) is different from zones 3 and 4; zone 2 (,77) is different from zone 4. Test of multiple omparisons (SNK) The zone 1 and 2 are the most similar. There were also differenes in the perentage of survival etween the four areas (ANOVA p=,22; zone 3 differed from others (Tukey). Summary regression: Total mortality= -,2865 * (management time in minutes) + 95,369; with a R 2 =,8218 (Fig. 7); survival = 75% and mortality = 25%. DISCUSSION The olive ridley turtle spawned all of 24, the highest proportion of turtles nesting ourred in August. The months with the highest numer of rood overs the period etween June and Novemer. Aording to Flores (1985) the inuation of the parrot turtle nest (Lepidohelys kempii) in Ranho Nuevo eahes, Tamaulipas naturally presents a slightly higher numer 8 L. olivaea m Sea FIG. 3. of the turtle nesting on the eah olive ridley L. olivaea. Adapted from Marquez (1996). Cuadernos de Investigaión UNED (ISSN: ) Vol. 5(1), Junio,

4 TABLE 1 Results of average numer of eggs, neonates living and perentage of survival y nest position. Numer of eggs Neonates living % Survival 2 9,5±19,19 48±27,5 52±28,5 3 94,2±2,8 48±29,8 49,9±3,1 4 95±18,86 48,2±24,8 52±27,1 5 95,5±21,62 55±25,9 58±26,7 6 94,2±15,1 63±31,9 69±32,2 The results are desried in media and standard deviation. Survival perentage a a a a a a a d a FIG. 6. Numer of roods per area and position. Survival (%) FIG. 4. Graphial ANOVA etween the preferential nesting on the eah site and the hathing. Perentage ars denote a,95% onfidene interval. 6 Numer of neonates Time (minutes) FIG. 7. Regression analysis of linear type with negative slope etween (Y) the numer of live neonates (total mortality) and (X) time management (Y=-,29X + 95,38 R 2 =, Numer of nests Numer of eggs Survival perentage FIG. 5. Numer of roods, survival perentage and numer of eggs y preferential site of nesting (position). of neonates live ompared with the nests transplanted to pens or polyurethane oxes. Boulon (2) says that the first and est option for handling is always eggs in situ protetion. In situ protetion in this area is very diffiult due to the looting and predation of luthes and turtles for this that the management (exavation, transportation and reseeded), is the est option. Aording to Marquez (1996), the position of the luth on the eah or the site on the eah eah gender hoose to nest is harateristi of eah speies and appears to e related to the size and the weight average of the animal. So the tortoises of the genus Lepidohelys arrive at Sandy arrier eahes and usually go up until the first erm or terrae, where it is ommon that nesting at the first attempt in learanes of vegetation, unless they are 1 Researh Journal of the Costa Rian Distane Eduation University (ISSN: ) Vol. 5(1), June, 213

5 an ostale as roots, roks or uried stiks, eause they will then seek a new site lose to the first, where will try again to dig the nest. In this ase refers to the loation of the roods of L. olivaea in position 2 to 5, for this the position of the luthes work inluded 2 through 6 is a position aove desried y Marquez (1996), although only ourred in the first two areas proaly sine these eah areas are more gentle slope on the other hand y omparing the perentage of survival etween positions we an see an inrease in the numer of infants live in position 6, whih is not listed as typial of the genus Lepidohelys, although the omparison of analysis of variane test indiates that there are no signifiant differenes, we an speulate otherwise with a 1 inrease in the perentage of survival. Harry & Limpus (1989) reommended that the eggs should not e moved at all in a span of 3 hours to 21 days after the oviposition. Garduño & Cervantes (1996), determine that survival in natural nests to the transplant is larger, in this ase the deisive variale is time management, eause the nests that are left in situ, not sujeted to a disturane y management is greater survival, also explained that the revival of nests may e affeted y the manipulation of eggs, sine after polarized the germinal dis in the emryo tilt or any slight hange in the, will inrease mortality. Naranjo (1989) explains that in the transplanted nests, the management does not affet if done with the greatest of are. Boulon (2) explains that after one period of more than 12 hours of eing nest, eggs should not ollet, sine the emryo adheres to the inside of the shell and the movement is fatal. This study found that after two hours of management time survival perentage dereases y, there is a linear trend that explains that mortality inreases with the inrease of management time and dereases the survival of infants orn. This allows information to implement monitoring plans to redue the time etween and redue luth handling times. Manipulation time represents a point of great relevane for the development of the fieldwork. The areas of highest inidene of turtles allowed us to estalish monitoring systems fousing on the areas where the highest proportion of nesting females ome. ACKNOWLEDGEMENTS We thank M. Ariniega-Rossano and the Working Group of the 24 season of El Verde CPCTM. We also thank to A. Núñez-Pastén and S. Rendón R. REFERENCES Boulon, R.H. Jr. (2). Reduión de las Amenazas a los Huevos y Las Crías: Proteión in situ. In K.E. Ekert, K.A. Bjorndal, F.A. Areu-Groois & M. Donnely (Eds.), Ténias De Investigaión Y Manejo Para La Conservaión De Las Tortugas Marinas. UINCN/CSE grupo Espeialista de Tortugas Marinas Puliaión No.192. Flores, S.I. (1985). Contriuión al estudio iologio de los nidos in situ de la tortuga lora Lepidohelys kempii (Garman, 198), en Ranho Nuevo, Aldama, Tamaulipas, Méxio. Tesis Profesional. Esuela de Cienias Biológias. Universidad del Noroeste. Tampio, Méxio. Fowler J. & Cohen, L. (199). Pratial Statistis for Field Biology. Primera puliaión. Trowridge, Wiltshire, Great Britain: Redwood Books. Garduño, A.M. & Cervantes H.E. (1996). Influenia de la temperatura y la humedad en la sorevivenia de nidos in situ y en orral de tortuga arey Eretmohelys imriata en las Coloradas, Yuatán, Méxio. INP. SEMARNAP. Cien. Pesq. 12, 9-97 Harry, J.L. & Limpus, C.J. (1989). Low-temperature protetion o marine turtle eggs during long-distane reloation. Austral. Wild. Res. 16, Limpus, C.J., Baker, V. & Millar, J.D. (1979). Movement-indued mortality of loggerhead eggs. Herpetol. 35, Limpus, C.J. (1995). Gloal overview of the status of marine turtles: a 1995 viewpoint. In Biology and onservation of sea turtles. Washington, D.C., USA: Smithsonian Institution Press. Márquez, M.R. (1996). Las tortugas marinas y nuestro tiempo. Fondo de Cultura Eonómia, Méxio. Montgomery, D. (1991). Diseño y análisis de experimentos. Méxio D.F., Méxio: Ieroameriana. Naranjo, G.A. (1989). Caraterístias del medio amiente de inuaión natural y su influenia en el porentaje de elosión de huevos de tortuga negra (Chelonia agassizi: Cheloniidae) en las playas de Colola y Maruata, Mihoaán. Tesis. Esuela de Biología. Universidad Mihoaana de San Niolás de Hidalgo. Morelia, Mihoaán, Méxio. Parmenter, C.J. (198). Inuation of the eggs of the green sea turtle, Chelonia mydas, in Torres Strait, Australia: the effet of movement on hathaility. Aust. Wild. Res. 7, Rihardson, J.I. (2). Prioridades Para Los Estudios Sore La Biología De La Reproduión y de la Anidaión. In Ténias De Investigaión Y Manejo Para La Conservaión De Las Tortugas Marinas. UINCN/CSE grupo Espeialista de Tortugas Marinas Puliaión No Cuadernos de Investigaión UNED (ISSN: ) Vol. 5(1), Junio,

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