Nesting activity of Olive ridley and effect of artificial shade at Cascajilloso Beach, a new inhabited nesting site in Pacific Panama
Data files
Oct 10, 2023 version files 49.29 KB
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Airtemp_rainfall.txt
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Corr_temp_inc.txt
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correl_hemb_neo.txt
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General_data.txt
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hatching_success_per_seasons.txt
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incubation_days_seasons.txt
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README.md
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Size_fem_season.txt
Abstract
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.
README
This README file was generated on 2023-03-27 by Eric E. Flores.
GENERAL INFORMATION
- Title of Dataset: Nesting activity of Olive ridley and effect of artificial shade at Cascajilloso Beach, a new inhabited nesting site in Pacific Panama.
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 PanamaEmail: 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
- Date of data collection (single date, range, approximate date): 2019-2021
- Geographic location of data collection: Cascajilloso beach, Panama
- 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
- Licenses/restrictions placed on the data: CC0 1.0 Universal (CC0 1.0) Public Domain
- Links to publications that cite or use the data: None
- Links to other publicly accessible locations of the data: None
- Links/relationships to ancillary data sets: None
- Was data derived from another source? No A. If yes, list source(s): NA
- 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
- 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
- Relationship between files, if important: None
- Additional related data collected that was not included in the current data package: None
- 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)
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DATA-SPECIFIC INFORMATION FOR: General data.txt
- Number of variables: 10
- Number of cases/rows: 595
- 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
- Missing data codes: NA (not applicable)
- Specialized formats or other abbreviations used: None
#########################################################################
DATA-SPECIFIC INFORMATION FOR: hatching success per season.txt
- Number of variables: 4
- Number of cases/rows: 241
- 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
- Missing data codes: None
- Specialized formats or other abbreviations used: None
#########################################################################
DATA-SPECIFIC INFORMATION FOR: incubation days_season.txt
- Number of variables: 2
- Number of cases/rows: 239
- Variable List:
- year: year of the nesting season (i.e. 2019, 2020, 2021)
- inc_days: incubation days of each nest in a given season
- Missing data codes: None
- Specialized formats or other abbreviations used: None
#########################################################################
DATA-SPECIFIC INFORMATION FOR: Size_fem_season.txt
- Number of variables: 4
- Number of cases/rows: 112
- 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
- Missing data codes: None
- Specialized formats or other abbreviations used: None
#########################################################################
DATA-SPECIFIC INFORMATION FOR: Corr_temp_inc.txt
- Number of variables: 6
- Number of cases/rows: 9
- 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
- Missing data codes: NA (not applicable)
- Specialized formats or other abbreviations used: None
#########################################################################
DATA-SPECIFIC INFORMATION FOR: Airtemp_rainfall.txt
- Number of variables: 6
- Number of cases/rows: 123
- 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
- Missing data codes: NA (not applicable)
- Specialized formats or other abbreviations used: None
####################################################
DATA-SPECIFIC INFORMATION FOR: correl_hemb_neo.txt
- Number of variables: 5
- Number of cases/rows: 11
- 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
- Missing data codes: NA (not applicable)
- Specialized formats or other abbreviations used: None
Methods
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. L. olivacea, Chelonia mydas and Eretmochelys imbricata 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: Cocos nucifera, Terminalia catappa, Canavalia rosea, Sphageticola trilobata 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 m2 (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 m2 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 < 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.
Usage notes
All the data files can be open using MSExcel.