Duke Albatross 1997-1999

Duke University Marine Laboratory

Four female and one male black-footed albatross (Phoebastria nigripes) were tracked using satellite telemetry during their post-breeding summer dispersal (July - September, 1997-1999). The females were tracked using transmitters that operated continuously, and the male was tracked using a duty-cycled transmitter programmed to transmit on 7-day ON:OFF cycles.

Albatross movements and foraging grounds during the post-breeding dispersal are poorly understood, despite their important conservation implications. We tracked four female black-footed albatross (Phoebastria nigripes) for 100 days during their summer (July-September, 1997-1999) post-breeding dispersal off California, and compared their movements to the distribution of fishing effort from the Japanese Eastern Pacific Ocean (EPO) longline fishery. The tracked birds foraged largely along the transition zone between the California Current and the Central Pacific Gyre, and spent 25, 24, and 51% of their time at sea within the 200 mile exclusive economic zones (EEZs) of the USA and Mexico, and the high seas (international waters) respectively. The satellite-tracked birds occupied subtropical waters (18-20 °C) targeted by longline fisheries for tuna (Thunnus spp.) and broad-bill swordfish (Xiphias gladius), and ranged disproportionately farther during daylight hours, when tuna fisheries operate. The available data suggest that albatrosses overlap temporally and spatially with longline fisheries in the northeast Pacific Ocean. However, this research cannot directly evaluate whether black-footed albatross bycatch occurs in these fisheries. The coarse temporal (monthly) and spatial (1°×1°) resolution of the fisheries data, and the dynamic nature of the fishing effort inhibited a fine-scale analysis of albatross overlap with longline fisheries. While we documented substantial spatial overlap between albatross distributions and the Japanese Eastern Pacific Ocean longline fishing effort during the 1980s, we found no co-occurrence during the 1990s. This study illustrates the value of satellite telemetry to assess national conservation responsibilities, and to identify potential interactions of protected species with fisheries not currently monitored by observer programs. Furthermore, our results underscore the need to exercise caution when interpreting satellite telemetry data for conservation purposes, because of the highly dynamic nature of pelagic fisheries.

These telemetry data were collected through the Argos system, using Telonics ST-10 transmitters (Telonics, Mesa, AZ) programmed to operate on a 90-second repetition rate. Bench-mark tests before transmitter deployment revealed the following median positional errors (in km) for different Argos location quality classes: 1.47 (lc0), 0.77 (lc1), 0.50 (lc2), 0.30 (lc3), 1.86 (lcA), 7.26 (lcB). Class B locations reached errors of up to 50 km. After removing low-quality class B locations the dataset contained 34.81% (lc0), 24.13% (lc1), 11.97% (lc2), 5.52% (lc3), 23.57% (lcA).



For further information, please refer to the references associated with this dataset.

Overview

Attributes described below represent those in the original dataset provided by the provider.
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Attributes in dataset

Attribute (table column)	Description
species	Species observed
gender	Gender
sexing_method	definition not provided
sexing_citation	definition not provided
age	Age
ageing_method	definition not provided
ageing_citation	definition not provided
telemetry_technique	definition not provided
tag_manufacturer	definition not provided
tag_model	definition not provided
series	definition not provided
tag_id_number	definition not provided
repetition_rate_(seconds)	definition not provided
duty_cycle	definition not provided
investigator_name	definition not provided
citation	definition not provided
location_quality_class	definition not provided
accuracy_metric	definition not provided
location_accuracy_(km)	definition not provided
year	Year of observation
month	Month of observation
day	Day of observation
timezone	Time zone
hours	Hours
minutes	Minutes
seconds	Seconds
latitude	Latitude of observation in decimal degrees
longitude	Longitude of observation in decimal degrees
geom	Geometry field added by OBIS-SEAMAP
oid	Unique ID number (generated by OBIS-SEAMAP)