DOI: 10.5061/dryad.m0cfxppcx
title: Revealing elasmobranch distributions in turbid coastal waters: insights from environmental DNA and particle tracking

description: Many sharks, rays, and skates are highly threatened and vulnerable to
 overexploitation, as such reliable monitoring of elasmobranchs is key to
 effective management and conservation. The mobile and elusive nature of
 these species makes monitoring challenging, particularly in temperate
 waters with low visibility. Environmental DNA (eDNA) methods present an
 opportunity to study these species in the absence of visual identification
 or invasive techniques. However, eDNA data alone can be difficult to
 interpret for species monitoring, particularly in a marine setting where
 its distribution can be influenced by water currents. In this study, we
 investigated the spatial and temporal distribution of elasmobranch species
 in two Special Areas for Conservation (SAC) off the coast of Wales. We
 took monthly eDNA samples for one year (starting September 2020 and March
 2022 for the northern and southern SACs, respectively), and used
 metabarcoding to reveal the presence of elasmobranch species. We combined
 these data with hydrodynamic modelling and particle tracking methods to
 simulate the potential origins of the detected eDNA. We detected 11
 elasmobranch species, including the Critically Endangered angelshark
 (Squatina squatina) and tope (Galeorhinus galeus). Most detections were in
 the spring and fewest in the autumn. The particle tracking simulations
 predicted that eDNA was shed, on average, approximately 7 km and 15 km (in
 the northern and southern SACs, respectively) from the sampling stations
 at which it was detected. These results show that the two SACs represent
 important areas for elasmobranchs in the United Kingdom and demonstrate
 that eDNA methods combined with particle tracking simulations can
 represent a new frontier for monitoring marine species.
description: # Revealing elasmobranch distributions in turbid coastal waters: insights
 from environmental DNA and particle tracking
 [https://doi.org/10.5061/dryad.m0cfxppcx](https://doi.org/10.5061/dryad.m0cfxppcx) ## Description of the data and file structure Revealing elasmobranch distributions in turbid coastal waters: insights from environmental DNA and particle tracking Raw sequence FASTQ data from 8 experimental run files from Illumina MiSeq paired-end sequencing of the Elas02 barcode. Files are named according to the sample location and date; "`Site-Date_Sequencer information.fastq`" i.e. AB-1020_S22_L001_R1_001.fastq is the data from site AB in October 2020 Where the Site is replaced by NegExt/NEG and NTC, it means negative extraction controls (DNA extraction control) and negative template controls (PCR control) respectively. All samples were processed with a corresponding negative control, designated with a 0 after the sample location ID e.g. "AB0_..." Sample locations are as follows: | **Location** | **Site** | **Latitude** | **Longitude** | | :----------- | :------- | :----------- | :------------ | | PLAS | AB | 52.5292 | -4.0492 | | PLAS | BA | 52.7177 | -4.0531 | | PLAS | BL | 52.9112 | -4.1906 | | PLAS | BO | 52.4802 | -4.0528 | | PLAS | CA | 52.8728 | -4.449 | | PLAS | DY | 52.7853 | -4.126 | | PLAS | HA | 52.8618 | -4.1275 | | PLAS | PE | 52.908 | -4.316 | | PLAS | PO | 52.8083 | -4.5508 | | PLAS | TY | 52.5823 | -4.1004 | | CBAE | TS | 51.6674 | -4.7014 | | CBAE | SA | 51.7112 | -4.6966 | | CBAE | PE | 51.7402 | -4.5586 | | CBAE | FE | 51.7692 | -4.3705 | | CBAE | SI | 51.7372 | -4.3565 | | CBAE | PB | 51.6742 | -4.3146 | | CBAE | BU | 51.6789 | -4.2359 | | CBAE | LL | 51.5941 | -4.2953 | | CBAE | PO | 51.5435 | -4.2072 | | CBAE | CA | 51.5683 | -4.0325 | PLAS: Pen Llŷn a'r Sarnau CBAE: Carmarthen Bay and Estuaries Data runs 5 and 6 did not produce results that were used in the analysis and are therefore not included here. ### Files and variables #### File: Data\_Run\_1.zip **Description:** FASTQ files from PLAS samples September to December 2020 #### File: Data\_Run\_2.zip **Description:** FASTQ files from PLAS samples January to April 2021 #### File: Data\_Run\_3.zip **Description:** FASTQ files from PLAS samples May to August 2021 #### File: Data\_Run\_4.zip **Description:** FASTQ files from CBAE samples March to June 2022 #### File: Data\_Run\_7.zip **Description:** FASTQ files from CBAE samples January to February 2022 #### File: Museum\_Run\_1.zip **Description:**  Rerun FASTQ files from CBAE samples July to December 2022 #### File: Museum\_Run\_2.zip **Description:** FASTQ files from CBAE samples November and December 2022 ## Code/software Analysed using the SimpleMetaPipeline (Williams et al. 2024) [J-Cos/SimpleMetaPipeline: 2.0.2](https://zenodo.org/records/11153890) ## Access information Other publicly accessible locations of the data: * Particle tracking and analysis scripts are available here: [https://zenodo.org/records/14391532](https://zenodo.org/records/14391532) Data was derived from the following sources: * environmental DNA samples from filtered water and MiSeq sequencing