UK Basking Shark sightings from 1987 to 2016
Marine Conservation Society
Description
Basking Shark Watch is a volunteer wildlife sightings scheme whereby records of basking sharks that have been sighted are submitted by the public or organisations to MCS with significant contributions from: RSPB; The Wildlife Trusts, The Shark Trust; Manx Wildlife Trust; Hebridean Whale and Dolphin Trust.. The scheme is specific to the UK and the sightings are mostly of live animals, at the sea surface. It is not set up to record zero abundance records. The scheme records the species Cetorhinus maximus only
o find out more about MCS Wildlife Sightings Schemes, visit http://www.mcsuk.org/what_we_do/Wildlifeprotection/Reportwildlifesightings. The manager of Basking Shark Watch is Jean-Luc Slandt, MPA Principal Specialist at MCS. MCS is happy to be contacted about this dataset and can provide a limited amount of support in its use.
Whilst MCS, The Shark Trust and The Wildlife Trusts were joint lead partners for the Biodiversity Action Plan, MCS remained the holder of the UK-wide Basking Shark Watch database. This means that all sightings data from those organisations has been compiled in our data. We have also used some permanent sightings schemes that have reported sharks on an annual basis to MCS such as Hebridean Whale and Dolphin Trust, RSPB.
Geographic Description
This is a UK-wide dataset but reports of surface sightings to Basking Shark Watch are reliant on the number of potential observers present in an area. Public participation is dependent on weather conditions, public holidays, dedicated surveys and the level of promotion of the scheme. MCS attempts to mitigate for regional bias and encourage greater UK project coverage by taking a national approach to the scheme’s promotion. Records were provided with latitude and longitude to 6 decimal places. More information about the dataset can be found here: http://www.mcsuk.org/downloads/wildlife/basking_sharks/BSW20%20Report.pdf
Purpose
The basking shark (Cetorhinus maximus) is the largest fish species in the Northeast Atlantic and the second largest in the world, growing in excess of 11 metres in length and weighing up to 7 tonnes. However, much of the basking shark’s life history, movements, population dynamics and general ecology had not been described. This lack of ecological data led the Marine Conservation Society (MCS) to launch the Basking Shark Watch project in 1987 as part of its campaign to protect the basking shark. Basking Shark Watch originally aimed to provide a general indication of the geographical distribution of basking shark surface sightings around the UK coast. The project involves members of the public and independent organisations recording details of their shark sightings and the subsequent collection and analysis of these records by MCS. The scheme’s aims are to:
Maintain a database of information on relative abundance, distribution and behaviour of basking sharks in UK waters;
Collect and analyse sightings data to improve our knowledge of basking shark ecology, population dynamics and behaviour;
Support and progress the UK Basking Shark Species Action Plan, and extended protection measures in Northeast Atlantic waters; and;
Raise public awareness about basking sharks and the threats they face.
Data quality
The ability of recorders to distinguish between different marine megafauna is uncertain. MCS have publicised marine wildlife watching codes with the Shark Trust that shows distinguishing features. HWDT train observers involved in their sightings schemes. Manx WT has trained observers and runs a recording programme that MCS started collaboratively with them in 2006. When sightings occur in unusual seasons (e.g. winter) or unusual locations (e.g. southern North Sea), MCS has historically investigated. A previous study has compared results from a similar public sightings scheme with effort-based surveys and found that the basking shark sightings data closely resembled that of the survey data, both spatially and temporally. Disparities did occur and were attributed to a lack of quantifiable effort, multiple counting and animal misidentification.We have also been uncertain of a number of sighitngs, and have validated the sightings using a number of different staff and volunteers at our Ross on Wye HQ when funds and volunteers have been available. We have also - in many instances - had to generate our own lat / longs from location data, particularly prior to 2014 when the recent version of our sightings page was created that auto-generates lat / longs.
Methods
Data is compiled and gathered by the Marine Conservation Society, with significant contributions from: RSPB; The Wildlife Trusts, The Shark Trust; Manx Wildlife Trust; Hebridean Whale and Dolphin Trust. This is a citizen science scheme that records ad hoc sightings of basking sharks. Data are submitted via email, phone or an online form. Required data include: status of animal (alive or dead), behaviour if alive, number sighted, date and time of sighting, location of observer (e.g. on land or on a boat), rough location of animal (e.g. in a bay or off a headland) as well as more precise location details (town name, lat long if possible). Lat longs are added if missing, or verified if present, during the validation process. Due to the nature of the methodology, information can only be gathered on the surface behaviour of the basking sharks seen and this is likely to be only a partial reflection of the behaviour of these animals. As with all non-effort based, public participation wildlife sightings schemes, Basking Shark Watch will generate “multiple sightings”, i.e. the same animal may be reported separately by different people. More information about the dataset can be found here: http://www.mcsuk.org/downloads/wildlife/basking_sharks/BSW20%20Report.pdf
Citation
No citation information available.
Information withheld
As the basking shark is a highly migratory species, undertaking annual migrations throughout the entire continental shelf of the British Isles, to France, Spain and even Portugal and the Azores, and back again, we recommend providing the data at 1km cell resolution.
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Digitised records
Looking up... the number of records that can be accessed through the NBN Atlas. This resource was last checked for updated data on 11 Feb 2020. The most recent data was published on 11 Feb 2020.
Click to view records for the UK Basking Shark sightings from 1987 to 2016 resource.