seals on ice

Haul-out Mode: It’s Not Just for Pinnipeds

seals on iceThe haul-out function is much more useful than first meets the eye. Not only will it alert you if the tag comes out of the water but it also improves Argos tag initialization results by extending the initialization transmission duration due to the slower haul-out repetition rate.

Hauling-out is generally associated with pinniped behavior because they “haul-out” of the water onto dry land. Haul-outs usually happen between foraging generally for resting or mating. In research, information on haul-out behavior is necessary for population estimates and conservation.

Beyond studying when a pinniped is out of the water, haul-out mode can also be used as a way to determine if your study animal washed ashore or was landed onto a boat. If haul-out mode is enabled, it will raise the haul-out flag in your tag data. We’ve seen use cases where haul-out flags helped researchers determine that sharks were taken by poachers. Haul-out mode is also useful when enabled in towed or asset tracking tags to help determine when a tag or sensor package has separated from the animal.

In tag programming, haul-out will start when a user-defined number of consecutive minutes pass in which the tag is “sufficiently dry.” “Sufficiently dry” means having enough dry readings measured—once per second—in a minute. Haul-out ends when enough wet readings occur in a minute.

Fastloc® GPS SPLASH tags include a haul-out option. When this is enabled, GPS snapshots are attempted during the haul-out and post-haul-out. The Haul-out.csv file will contain the haul-out number, start time, end time, and duration.

The haul-out data product is one tool to identify haul-out events. However, when monitoring things like sea turtle nesting events, we also recommend enabling Percentage Dry Timelines and DDN (Dry, Deep, Neither) data products for further evidence that a nesting attempt occurred.

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