https://doi.org/10.5061/dryad.cfxpnvxgn

Description of the data and file structure

Since September 2015, the Exclusive Economic Zone of Saba (Dutch Windward Islands) has been designated Yarari Marine Mammal and Shark Sanctuary. However, to effectively conserve sharks, a baseline on their diversity, population structure, habitat use, and spatiotemporal distribution is needed. We used three monitoring methods: acoustic telemetry, stereo-baited remote underwater video systems (stereo-BRUVs), and a long-term citizen science program to study reef-associated sharks, mainly Caribbean reef shark (Carcharhinus perezi) and nurse shark (Ginglymostoma cirratum) around the island of Saba during 2012-2020. Based on the stereo-BRUVs, we determined that the presence of Caribbean reef sharks (0.25±0.48 maxN/hour; mean ± s.d.) and nurse sharks (0.20±0.45 maxN/hour) was relatively high compared to other Caribbean reefs. With acoustic telemetry, we showed that the residence and site fidelity of Caribbean reef sharks is high, especially for immature individuals. In addition, we show a higher presence of Caribbean reef sharks during December-May and a lower overall presence of adult males. The citizen science program showed an increase in observations of both species between 2012 and 2020, possibly indicating an increase in abundance. We demonstrate that these three methods can be used complementary to provide an essential baseline of the diversity and spatiotemporal presence of reef-associated sharks.

Files and variables

File: StudyData.zip

Description: 

Repository structure:

1. Data

1. Sharkdata.CSV: the information on each individual shark included in the acoustic telemetry of this study.
   • species: scientific name of species detected.
   • transid: transmitter identification number.
   • stage: life stage (juv = juvenile, ad = adult)
   • length: total length in cm.
   • sex: male (m) or female (f)
   • catchdate: date of capture.
   • catchtime: time of capture.
   • location: location name of capture.
   • latitude: in decimal degrees.
   • longitude: in decimal degrees
   • catch method: capture method.
2. Receiverdata.CSV: the information on each acoustic receiver included in this study.
   • namelocation: name of the location of receiver. 
   • receiverid: unique identification number of receiver.
   • latitude: in decimal degrees.
   • longitude: in decimal degrees.
   • mooringSCF: mooring number local organizations.
   • mooringSeaSaba: mooring number local organizations.
   • recdepth: depth in meters of receiver.
   • waterdepth: water depth in meters at location.
   • date: date of installation of receiver.
   • time: time of installation.
   • deploymgentmethod: if receiver was places on standalone setup on attached on existing (dive) mooring.
3. Saba_AT.CSV: acoustic transmitter data of Caribbean reef sharks and nurse sharks.
   • Transmitter: transmitter identification number of detection.
   • Date: date and time of detection.
   • Receiver: receiver identification number.
   • Island: island where receiver was placed (=Saba)
   • Location: location name of receiver.
   • Latitude: latitude of receiver in decimal degrees.
   • Longitude: longitude of receiver in decimal degrees.
   • LocationID: identification number for site were receiver was placed.
   • Sensor_value: depth in meters.
   • Sensor_unit: meters
   • Day: day of detection.
   • Hour: hour of detection.
   • Month: month of detection.
   • Year: year of detection.
4. detind.CSV: statistics on detections per individual shark.
   • Location: location where the receiver was located.
   • Species: species detected.
   • Latitude: in decimal degrees.
   • Longitude: in decimal degrees.
   • DaysDet: number of days that a species was detected on the receiver.
   • DaysDet_P: the days detected as a proportion of study length.
5. BRUV.CSV: main stereo baited underwater video system data included in the study.
   • ID: unique deployment number.
   • Species: scientific name of species observed.
   • Depth: depth class (15, 50 or 100 meters).
   • Zone: management zone in which the site is located (RD = recreational diving zone, MU = multi-purpose zone).
   • Side: side of the island.
   • Relief: reef relief class.
   • FL_cm: fork length in centimeters.
   • Opcode: observation identification number.
   • SharkCode: code for species observed (reef for Carcharhinus perezi, and nurse for Ginglymostoma cirratum)
6. pAlldives_VC.CSV: proportion of all dives on a location that Caribbean reef and/or nurse sharks were observed.
   • id: unique id of dive site.
   • name: name of dive site.
   • lat: latitude in decimal degrees.
   • lon: longitude in decimal degrees.
   • p_CR: proportion of dives that a Caribbean reef shark was detected on this site.
   • p_NU: proportion of dives that a nurse shark was detected on this site.
   • zone: management zone in which the dive site is located (RD = recreational diving zone, MU = multi-purpose zone).
7. CPUE_VC.CSV: the number of sharks per dive observed for each dive location.
   Columns:
   • ID: unique dive identification number
   • name: name of the dive site
   • lat: latitude in decimal degrees
   • lon: longitude in decimal degrees
   • CPUE_CR: the mean number of Caribbean reef sharks observed per dive (n/dive).
   • CPUE_CR.se: the standard error number of Caribbean reef sharks observed per dive (n/dive).
   • CPUE_NU.se: the standard error number of nurse sharks observed per dive (n/dive).
   • CPUE_NU.se: the standard error number of nurse sharks observed per dive (n/dive).
   • zone: management zone in which the dive site is located (RD = recreational diving zone, MU = multi-purpose zone).

2. Code

1. func.R: user defined functions used in the main R-script.
2. master.R: main R-script used for analysis.

Code/software

R environment

Access information

Other publicly accessible locations of the data:

• n/a

Data was derived from the following sources:

• n/a