DOI: 10.5061/dryad.bk3j9kdhd
title: Nesting activity of Olive ridley and effect of artificial shade at Cascajilloso Beach, a new inhabited nesting site in Pacific Panama

description: Sea turtle nesting activity on newly monitored beaches yields important
 data to support future regional and global conservation assessments. Here
 we report on nesting activity of Olive Ridley (Lepidochelys olivacea) at
 Cascajilloso Beach in Pacific Panama based on data from a new hatchery
 during seasons 2019, 2020 and 2021. Besides, we conducted a field
 experiment analyzing the effects of artificial shading on hatchlings’
 biometric characteristics, hatching success and the incubation period.
 Nesting activity based on number of egg clutches transferred to the
 hatchery reached a peak between September (33%) and October (25%). Curved
 carapace length (CCL) of nesting females (64.3–66.2 cm) was similar to
 other populations of the Eastern Tropical Pacific (ETP). The number of egg
 clutches was 80 in 2019, 74 in 2020 and 108 in 2021, however, the clutch
 size was slightly smaller (91.5 to 94.5 eggs) compared with other
 populations of the ETP. This could be a phenotypic variation of nesting
 females at this beach. The ability to move egg clutches to the hatchery
 was affected during 2020 season due to COVID-19 restrictions. Heavy
 rainfall during the incubation period influenced the nest temperatures
 registered under artificial shade and unshaded treatments (maximum average
 29.9 °C), potentially resulting in males. The warmer temperatures in our
 experimental nests produced heavier hatchlings contrary to general
 assumptions, but this was also related to straight carapace length only
 after a threshold value of 40 mm. Hatchlings under the artificial shade
 were able to grow to a certain size but potentially at the cost of storing
 less mass (trade-off). The ongoing beach patrolling and hatchery
 management techniques with long-term baseline data collection are needed
 to secure the nesting population of L. olivacea at this recently surveyed
 beach.
description: Study
 site Cascajilloso Beach is located
 on the west coast of the Azuero Peninsula in Pacific Panama (7°22'N,
 80°54'W, Figure 1). The beach length is 6.7 km and beach width is 30
 m. <em>L. olivacea</em>, <em>Chelonia mydas</em>
 and <em>Eretmochelys imbricata</em> are reported to nest at
 the site (Flores et al. 2021). The sand is gray to black with the Pavo
 river mouth bordering the southern extreme of the beach. The vegetation of
 the beach includes: <em>Cocos nucifera, Terminalia catappa,
 Canavalia rosea, Sphageticola trilobata </em>and some grasses
 (Flores et al., 2021).  Beach patrolling and nesting
 females Beach patrols were conducted on
 foot every night when possible and depending on meteorological conditions
 during the nesting seasons. The patrol team was composed of two park
 rangers from MiAmbiente and occasionally a community member from Arenas
 town. Patrol duration (hours) was calculated from the time a beach survey
 started until the time it ended. We also calculated the per-kilometer
 patrol duration (hours per km), defined as the patrol duration for each
 night divided by the length (km) of the beach.
 Each nesting female was
 measured for her curved carapace length (CCL) and curved carapace width
 (CCW) using a flexible measuring tape and Inconel flipper tags (Style 681,
 National Band and Tag Company, Newport, Kentucky, USA) were used to mark
 encountered females. Flipper tags were applied to the left front flipper
 (Balazs, 1999). Many nesting females left the beach before they could be
 measured yet their egg clutches were transferred to the
 hatchery. Cascajilloso Beach
 hatchery A hatchery with a maximum
 capacity of 176 nests was constructed in 2019. Inside the hatchery, an
 area of 0.25 m<sup>2</sup> (50 cm x 50 cm) was used to
 transfer each relocated nest. The hatchery was protected with chain link
 mesh and a 30 cm high black plastic sheet all around to avoid the
 intrusion of crabs and other predators. Prior to the start of each season,
 the sand was cleaned, sieved and exposed to sunlight during 15 days prior
 to the transfer of the first nests. Only during the 2020 season, the sand
 was extra treated with a dilution of Clorox® as a disinfectant because of
 the presence of mites in some of the nests during 2019. The date that the
 egg clutch was laid was registered in a logbook and the predicted hatch
 date was calculated to be between 45 to 55 days. A circular anti-insect
 netting was placed on top of each nest to protect it from parasite wasps
 and other insects. Once hatched, hatchlings were immediately released into
 the sea to avoid being attacked by predators. Hatching date was noted as the
 day disturbances were found on the surface of the nest caused by either
 hatchlings underneath or emerging hatchlings (see Castheloge et al.,
 2018). The number of dead and live hatchlings from each nest were counted
 and hatching success was determined as the number of hatchlings (dead and
 alive) divided by the total number of eggs in the nest. Incubation success
 was calculated as the number of hatchlings successfully released into the
 sea divided by the total number of
 eggs.   Artificial shade
 experiment During August 2020 an area 6
 m<sup>2</sup> and 2 m high inside the hatchery was used for
 the artificial shade treatment in which an 80% shade cloth was used above
 ground on top of a wooden post structure. The clutches of 11 nesting
 females were collected at the beach after females finished laying. In no
 less than two hours (Limpus et al., 1979) each clutch was transferred to
 the hatchery using a split-clutch design, in which half of the clutch was
 randomly transferred to the shaded area and the other half to the unshaded
 area of the hatchery. A humidity and temperature data logger sensor Tempo
 Disc® (Blue Maestro, London UK) was buried at the center of each
 experimental treatment clutch.. Each sensor was calibrated against an
 anemo-thermo-hygrometer Skywatch model ATMOS (JDC Electronic SA,
 Switzerland) and set to register temperature every 15 min. An air
 temperature and humidity CS125 sensor (Campbell Scientific, USA) connected
 to a CR200 datalogger (Campbell Scientific, USA) was also installed 1.5 m
 above ground near the hatchery to measure these variables every hour. Due
 to damage the datalogger stopped recording on day 61 of the overall
 incubation period. Rainfall data was downloaded for the location of
 Cascajilloso Beach from the PERSIANN (Precipitation Estimation from
 Remotely Sensed Information using Artificial Neural Networks) system
 developed by the Center for Hydrometeorology and Remote Sensing (CHRS) at
 the University of California, Irvine (https://chrsdata.eng.uci.edu/). For each hatchling, the hatching date was recorded. Straight carapace length (SCL) was measured using a caliper Mitutoyo® (Mitutoyo American Corporation, USA). Body mass was measured using a digital scale AWS® model 100 CAL (American Weight Scales, Georgia USA). Each Tempo Disc datalogger was retrieved, the data were downloaded, and daily average temperature was calculated. However, due to the extremely wet conditions, 50 % of dataloggers failed to record data (five under unshaded treatment and six under shaded treatment). Hatching success and incubation success were also calculated for the experimental nests and were excluded from the overall 2020 season dataset. This is because the experimental clutches only had half of the eggs laid by females compared to those in the rest of the hatchery so as to allow comparison with seasons 2019 and 2021. After the biometric measurements were recorded the hatchlings were released into the sea.  Statistical analysis Prior to analyses, data was inspected for normality. When parametric assumptions were not met, non-parametric tests were performed. To compare the effect of artificial shade and direct sunlight on hatching success, incubation period and body mass, we used a Generalized Mixed Model (GLMM) with treatment as fixed factor and female tag number as a random factor and corresponding error structure. To test differences among nesting seasons of the measured variables we conducted non-parametric Kruskal-Wallis tests. Correlations among variables were tested using non-parametric Spearman rank correlation tests. P &lt; 0.05 was considered statistically significant, and models were simplified by backward elimination starting with the interaction term(s) where appropriate. Statistical analyses were conducted using R v.4.1.2 (R Development Core Team, 2021). All values reported in the results are means ± SD, unless otherwise indicated.
description: All the data files can be open using MSExcel.
description: This README file was generated on 2023-03-27 by Eric E. Flores. GENERAL
 INFORMATION 1. Title of Dataset: Nesting activity of Olive ridley and
 effect of artificial shade at Cascajilloso Beach, a new inhabited nesting
 site in Pacific Panama. 2. Author Information A. Principal Investigator
 Contact Information Name: Eric E. Flores Institution: Coiba Scientific
 Station (COIBA AIP) Address: Gustavo Lara street, building 145B, City of
 Knowledge, Clayton, PO Box 0843-01853, Panama, Republic of Panama ```
 Email: eflores@coiba.org.pa ``` B. Associate or Co-investigator Contact
 Information Name: Joelbin Rafael De La Cruz Institution: Ministry of
 Environment of Panama, Protected Areas and Biodiversity Directorate
 Address: Bldg. 804, Albrook, Ancon, Panama, Republic of Panama ``` Email:
 jcruza@miambiente.gob.pa ``` 3. Date of data collection (single date,
 range, approximate date): 2019-2021 4. Geographic location of data
 collection: Cascajilloso beach, Panama 5. Information about funding
 sources that supported the collection of the data: Secretaría Nacional de
 Ciencia Teconologya e Innovación, Grant Number 13-2020 SHARING/ACCESS
 INFORMATION 1. Licenses/restrictions placed on the data: CC0 1.0 Universal
 (CC0 1.0) Public Domain 2. Links to publications that cite or use the
 data: None 3. Links to other publicly accessible locations of the data:
 None 4. Links/relationships to ancillary data sets: None 5. Was data
 derived from another source? No A. If yes, list source(s): NA 6.
 Recommended citation for this dataset: Flores De Gracia, Eric Enrique; De
 la Cruz, Joelbin (2023). Nesting activity of Olive ridley and effect of
 artificial shade at Cascajilloso Beach, a new inhabited nesting site in
 Pacific Panama [Dataset]. Dryad. https://doi.org/10.5061/dryad.bk3j9kdhd
 DATA & FILE OVERVIEW 1. File List: A) General data.txt B) hatching
 success per season.txt C) incubation days\_season.txt D)
 Size\_fem\_season.txt E) Corr\_temp\_inc.txt F) Airtemp\_rainfall.txt G)
 correl\_hemb\_neo.txt 2. Relationship between files, if important: None 3.
 Additional related data collected that was not included in the current
 data package: None 4. Are there multiple versions of the dataset? No A. If
 yes, name of file(s) that was updated: NA (not applicable) i. Why was the
 file updated? NA (not applicable) ii. When was the file updated? NA (not
 applicable)
 #########################################################################
 DATA-SPECIFIC INFORMATION FOR: General data.txt 1. Number of variables: 10
 2. Number of cases/rows: 595 3. Variable List: * fem.id: unique code for
 each sea turtle nesting female which eggs were used in the artificial
 shade vs unshaded treatment experiment * hactchl\_id: numeric code for
 each hatchling of a given sea turtle female in each treatment * trt:
 experimental treatment (i.e. sol = unshaded treatment; som = artificial
 shade treatment) * scl: straight carapace length of hatchlings in mm in
 each treatment * mass: body mass of hatchlings in grams in each treatment
 * inc\_days: incubation days of hatchlings in each treatment * clutch:
 clutch size of each sea turtle female in each treatment * hatchlings:
 number of live hatchlings from each sea turtle female in each treatment *
 Tprom: average temperature of each nest during the incubation period in °C
 in each treatment * Tsecthird: average temperature of each nest during the
 second third of incubation period in °C in each treatment 4. Missing data
 codes: NA (not applicable) 5. Specialized formats or other abbreviations
 used: None
 #########################################################################
 DATA-SPECIFIC INFORMATION FOR: hatching success per season.txt 1. Number
 of variables: 4 2. Number of cases/rows: 241 3. Variable List: * year:
 year of the nesting season (i.e. 2019, 2020, 2021) * clutch: clutch size
 of each sea turtle nesting female in a given season * hs: hatching success
 in decimals * is: incubation success in decimals 4. Missing data codes:
 None 5. Specialized formats or other abbreviations used: None
 #########################################################################
 DATA-SPECIFIC INFORMATION FOR: incubation days\_season.txt 1. Number of
 variables: 2 2. Number of cases/rows: 239 3. Variable List: * year: year
 of the nesting season (i.e. 2019, 2020, 2021) * inc\_days: incubation days
 of each nest in a given season 4. Missing data codes: None 5. Specialized
 formats or other abbreviations used: None
 #########################################################################
 DATA-SPECIFIC INFORMATION FOR: Size\_fem\_season.txt 1. Number of
 variables: 4 2. Number of cases/rows: 112 3. Variable List: * year: year
 of the nesting season (i.e. 2019, 2020, 2021) * ccl: curved carapace
 length in cm from each nesting female in each nesting season * ccw: curved
 carapace width in cm from each nesting female in each nesting season *
 eggs: number of eggs in a clutch of each sea turtle nesting female in each
 nesting season 4. Missing data codes: None 5. Specialized formats or other
 abbreviations used: None
 #########################################################################
 DATA-SPECIFIC INFORMATION FOR: Corr\_temp\_inc.txt 1. Number of variables:
 6 2. Number of cases/rows: 9 3. Variable List: * trt: experimental
 treatment (i.e. sol = unshaded treatment; som = artificial shade
 treatment) * inc\_days: incubation days of hatchlings in each treatment *
 Tprom: average temperature of each nest during the incubation period in °C
 in each treatment * mass: body mass of hatchlings in grams in each
 treatment * scl: straight carapace length of hatchlings in mm in each
 treatment 4. Missing data codes: NA (not applicable) 5. Specialized
 formats or other abbreviations used: None
 #########################################################################
 DATA-SPECIFIC INFORMATION FOR: Airtemp\_rainfall.txt 1. Number of
 variables: 6 2. Number of cases/rows: 123 3. Variable List: * date: date
 of the year (format dd/mm/year) * Incubation\_days: days corresponding to
 the first day of incubation of nests in the hatchery in the first season
 (i.e. 2019) until the last day of incubation of nests of the last season
 (i.e. 2021) * Mean\_temp: Average air temperature measured near the
 hatchery in °C * Max\_temp: Maximum air temperature measured near the
 hatchery in °C * Min\_temp: Minimum air temperature measured near the
 hatchery in °C * Rain: Total rainfall for each day in mm 4. Missing data
 codes: NA (not applicable) 5. Specialized formats or other abbreviations
 used: None ####################################################
 DATA-SPECIFIC INFORMATION FOR: correl\_hemb\_neo.txt 1. Number of
 variables: 5 2. Number of cases/rows: 11 3. Variable List: * fem.id:
 unique code for each sea turtle nesting female which eggs were used in the
 artificial shade vs unshaded treatment experiment * ccl: curved carapace
 length in cm from each nesting female in each nesting season * sclsol:
 straight carapace length in cm for hatchlings in the unshaded treatment *
 sclsom: straight carapace length in cm for hatchlings in the artificial
 shade treatment * ccw: curved carapace width in cm from each nesting
 female in each nesting season 4. Missing data codes: NA (not applicable)
 5. Specialized formats or other abbreviations used: None