Tag: behavior

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Autumn movements of fin whales (Balaenoptera physalus) from Svalbard, Norway, revealed by satellite tracking

Lydersen and colleagues set out to investigate fin whales and their migratory paths using satellite tracking. Tags were deployed on 25 fin whales and stayed attached for a range of 6 to 95 days with an average duration of 33. It was found that 10 of the 25 individuals stayed within the study region, and 15 individuals travelled out of the immediate study area and tracks varied among individuals. Environmental variables such as ocean depth, sea surface temperature, and distance to the nearest coast were extracted from geodatabases given the location of the whales. In this case, Lydersen extracted bathymetry data from the ETOPO 1 Arc-Minute global relief data set from the National Geophysical Data Center, NOAA, sea surface temperature from the Extended Reconstructed Sea Surface Temperature (ERSST) v5, and finally distance to the nearest coast from the land file (1:10 m) from www.naturalearthdata.com.

Track maps of whales are an incredible tool in both visualizing and analyzing whale movements. These tracks provide important information on foraging behavior, activity level, and migratory destinations or lack thereof. The locations that satellite tags transmit allow for extraction of environmental variables from a variety of geodatabases, such as those listed above, that can provide further insight into whale behavior and foraging strategies.

Lydersen, C., Vacquié-Garcia, J., Heide-Jørgensen, M.P., Øien, N., Guinet, C. & Kovacs, K.M. (2020) Autumn movements of fin whales (Balaenoptera physalus) from Svalbard, Norway, revealed by satellite tracking. Scientific Reports, 10, 16966.

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Diving behavior of sperm whales in relation to behavior of a major prey species, the jumbo squid, in the Gulf of California, Mexico

Sperm whales in the Gulf of California prey heavily upon jumbo squid, which has been verified through stomach content analysis and stable isotope analysis, although sperm whale hunting behavior has remained understudied. Davis and colleagues attached satellite dive recorders to 5 sperm whales and 3 jumbo squid to investigate the diving behavior of these two mesopelagic predators. This study found that sperm whales dive and hunt within the same depth ranges that jumbo squid persist, around 100 to 500 meters deep. Results also indicate that squid may be more susceptible to predation following surfacing events in which they feed, and at depths of greater than 250 meters where oxygen content of the water is decreased.

This study showed the use of geographic data to analyze the predator-prey interactions in a marine environment. Maps within the paper, which show bathymetry layered beneath whale tracks, exemplify the use of GIS software ArcView to show the spatial content of both species within the study region of the Guaymas Basin of Baja California. Annotated maps implemented both spatial and temporal data to show the tracks of the 5 sperm whales over the duration of the study. Although this study did not make use geographic information science, the use of maps and visual context is vital to investigating species behavior and movement trends. Tracks such as these are directly applicable to data I am working with, but at a shorter temporal scale.

Davis, R., Jaquet, N., Gendron, D., Markaida, U., Bazzino, G. & Gilly, W. (2007) Diving behavior of sperm whales in relation to behavior of a major prey species, the jumbo squid, in the Gulf of California, Mexico. Marine Ecology Progress Series, 333, 291–302.