TABLE 1.

Methods for studying movement in freshwater fishes. Methods are broadly classified into mark-recapture and telemetry-based approaches. Technology provides the commonly used name for each method and description provides a brief summary of how the method operates. Advantages, disadvantages, and representative literature for each method are also provided.

	Technology	Description	Advantages	Disadvantages	Literature
Mark-recapture	Anchor tags	Attached to organisms as an identification tool at a tagging event and subsequent recapture	Low cost, well-established method	Limited movement information value, from only mark and recapture events	Thorstad et al. (2013)
			Can be used to estimate population size
	Passive integrated transponder tags (PIT)	Small electronic tags, often internally implanted in an organism. Researchers detect the PIT tag with a handheld device or automated station	Weigh < 1 g	Short detection distance of the readers (<1 m)	Thorstad et al. (2013)
			No battery is needed		Hedger et al. (2013)
			Lifetime of several decades
	Visible Implant Elastomer Tags (VIE)	Colored tags where elastomer is injected as a liquid and solidifies. Tags are placed beneath clear or translucent tissue and remain externally visible	Useful in a wide variety of species	Limited utility when many individuals must be tracked simultaneously	Hohn and Petrie-Hanson (2013)
			Can be used in very small organisms
			Flexible		Walsh and Winkelman, (2004)
			Biocompatible
	Close-kin mark-recapture	Employed to track individuals and populations based on genotype-derived estimates of kinship. The genetic information is collected via adipose fin clips	Only fin clip is required from fish	Molecular resources required	Bravington et al. (2016)
					Marcy-Quay et al. (2020)
Telemetry	Pop-up satellite tag (PSAT)	Archival tag that collects information for a specific period and relays that information to receivers via satellites	Enables large scale ocean migration studies of large fish	Tags are large and must be attached externally	Thorstad et al. (2013)
			Do not need to be recovered to retrieve data		Raby et al. (2017)
			Encourages public participation as a receiver array is not necessary and the public can report the captured tags
	Global positioning system tag (GPS)	Tags that gather accurate spatial information from Global Positioning System satellites and can transmit or store that information	Enables tracking of very small individuals due to radio and GPS tag miniaturization	Limited in aquatic systems because signals must be transmitted at or near the water’s surface	Sims et al. (2009)
			Very accurate	Often requires a tether to follow the fish, allowing the tag to get GPS data from near or at the water’s surface	Evans et al. (2011)
					Riding et al. (2009)
	Acoustic & Radio Arrays	A receiver array is established, then fish are tagged with acoustic or radio transmitters. Data is collected from receivers, revealing fish locations over time	Acoustic arrays work in both fresh water and saltwater. Radio arrays work in saltwater	High initial cost for establishing array	Hussey et al. (2015)
			Autonomous operation	Precision of movement information limited by the density of the receiver array	Cooke et al. (2008)
			Cost-efficient after array is established		Donaldson et al. (2014)
			Multiple species can be monitored at once	Movement information limited to the spatial coverage of the array	Enders et al. (2019)
	Predation transmitter (acoustic tag)	Acoustic tags that are sensitive to predation events. Transmitters change their acoustic identifier in response to acidic conditions in a predator’s stomach. This shift in identifier marks a predation event and tags can record the predator’s movement	Accurate (shown to verify a predation event 90% of the time)	Limited data collection time after predation event	Halfyard et al. (2017)
					Schultz et al. (2017)
			Could aid in describing aspects of predator feeding behavior and physiology		Weinz et al. (2020)
					Klinard et al. (2019)