Cetacean sightings in Ghana and Ivorycoast
Marijke de Boer
Dataset credit
Marijke N. de Boer
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Contacts
Role | Name | Organization | |
Primary contact |
Marijke de Boer |
Wageningen Marine Research, University of Wageningen |
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Data entry |
Ei Fujioka |
Duke University |
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Citation
Halpin, P.N., A.J. Read, E. Fujioka, B.D. Best, B. Donnelly, L.J. Hazen, C. Kot, K. Urian, E. LaBrecque, A. Dimatteo, J. Cleary, C. Good, L.B. Crowder, and K.D. Hyrenbach. 2009. OBIS-SEAMAP: The world data center for marine mammal, sea bird, and sea turtle distributions. Oceanography. 22(2):104-115.
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Abstract
Within the Gulf of Guinea the information on the cetacean abundance and distribution is scarce. A cetacean survey took place during geophysical surveys (2013–2014) along the coasts of Ghana and Côte d’Ivoire. Due to large group-sizes, melon-headed whales were the most abundant (0.34 animals km−1) followed by Fraser’s dolphins and short-finned pilot whales. Range state records were confirmed for melon-headed whale and Fraser’s dolphin in Ivoirian waters and ten further species represented first at-sea sightings. Fraser’s dolphins, melon-headed whales, pantropical spotted dolphins, bottlenose dolphins, and pilot whales were recorded in areas with the highest fishing densities. Melon-headed whales, pilot whales, and rough-toothed dolphins were observed in vicinity of trawlers; bottlenose dolphins, pantropical spotted dolphins, and pilot whales in vicinity of canoes. The poor knowledge on population trends of cetaceans in this unique upwelling region, together with a high demand for cetacean products for human consumption (as “marine bushmeat”) may lead to a potential decline of some species that may go unnoticed. These new insights can provide a foundation for the urgently required risk assessments of cetacean mortality in fisheries within the northern Gulf of Guinea.
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Purpose
The objective of this study was to gather new information on the poorly monitored local cetacean populations in order to understand the threat posed by interactions with fisheries either due to unintended bycatch (entanglement) or direct capture. The information presented provides a valuable insight into the occurrence, relative abundance, and at-sea distribution of cetaceans and an indication as to which cetacean species appear to be under the greatest fishing pressure. As such, these findings provide new directions for future assessments of fishing pressure on cetaceans through incidental catches and directed takes.
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Supplemental information
Information regarding location of fishing vessels is available upon request
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References
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Attributes
Overview
This section explains attributes included in the original dataset.
OBIS-SEAMAP restricts the attributes available to the public to date/time, lat/lon and species names/counts only.
Should you need other attributes described here, you are encouraged to contact the data provider.
Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downloadable online. Other attributes may be obtained upon provider's permission.
Attributes in dataset
Attribute (table column) | Description |
oid | Unique ID number (generated by OBIS-SEAMAP) |
sighting_no | Sighting Number |
date_time | Date and time at local time zone |
datetime_utc | Date and time at UTC |
observer | The name of the observer who first sighted the animal |
latitude | Latitude in decimal degrees |
longitude | Longitude in decimal degrees |
depth | Water depth (metres) |
species | Species name |
latin_name | Latin name |
sp_tsn | Taxonomic Serial Number added by OBIS-SEAMAP |
certainty | Certainty |
bearing | Bearing to animal |
range_of_animal | Range of animal (metres) |
total_number | Total number of animals sighted |
num_adults | Number of adults |
num_juveniles | Number of juveniles |
num_calves | Number of calves (visual sightings only) |
photo | Photo (yes/no) |
behaviour | Behaviour |
direction_relative | Direction of travel (relative to ship) |
direction_compass | Direction of travel (compass points) |
sea_state | Sea state |
swell | Swell |
visibility | Visibility |
glare | Glare |
precipation | Precipation |
sst | SST in celsius |
timezone_h | Time zone added by OBIS-SEAMAP |
geom | Geometry field added by OBIS-SEAMAP |
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Visit contributors' websites #1 #2
OBIS-SEAMAP ID | 2018 |
Seabirds | 0 |
Marine mammals | 315 |
Sea turtles | 0 |
Rays and sharks | 0 |
Other species | 0 |
Non spatial | 0 |
Non species | 0 |
Total | 315 |
Date, Begin | 2013-04-18 |
Date, End | 2014-05-24 |
Temporal prec. | 111110 |
Latitude | 3.60 - 4.87 |
Longitude | -3.44 - -1.85 |
Coord. prec. | 5 decimal digits |
Platform | Boat |
Data type | Animal sighting |
Effort | N/A |
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Traveled (km) | 0 |
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Registered | 2019-10-03 |
Updated | 2019-10-14 |
Status | Published |
Sharing policy |
CC-BY-NC (Minimum) |
Shared with |
OBIS
GBIF (via DOI) |
See metadata in static HTML |
See metadata in FGDC XML |
See download history / statistics |
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