Adding Animal Movement Data to Ocean Observing Systems
Sandra Greer, Amirix Systems, Vemco Division. Halifax, NS Canada.
The objective of this poster is to show how the idea of adding animal movement data from
current acoustic fish tags and future “Integrated Tags” to existing and future Ocean Observation
Systems provides information of high economic value and complements biologging data which
is only obtainable from larger fish because of the size of the tags.
An Emerging World Wide Fish Tracking Network
Acoustic tagging has been a well established tool for determining movements and behaviour of
free-swimming fish for decades. In recent years, there has been a significant expansion of
acoustic Passive Tracking (see Heupel, Semmens and Hobday, 2006, for a review) in which
stationary receivers log the passage or residency of tagged fish over extended periods of time.
LaCroix and Voegeli (2000) first demonstrated the feasibility of employing passive tracking
employing a long line (42 km in this case) on the ocean floor to monitor fish passage. This
concept formed the basis of the Pacific Ocean Shelf Tracking Project (POST) whose
infrastructure includes a number of acoustic curtains extending from California to Alaska with
the initial intent of determining what was happening to salmon smolt when they leave the rivers
and enter the ocean. In addition, the arrays have provided valuable data on the migration of a
number of other species.
The success of the early initiatives described above has led to an expanding number of projects
such as the Australian Acoustic Tracking and Monitoring Systems (AATAMS), Florida Atlantic
Coast Telemetry Project (FACT) and the Ocean Tracking Network (OTN). The network has two
1. All receivers are capable of detecting all transmitters
2. ID codes transmitted from each tag are unique (i.e. each individual animal can be
which combine to provide the means and motivation for various initiatives to come together as
an informal worldwide tracking network. This is allowing researchers to gather data on tagged
fish far beyond what would be possible with a project specific installation. Figure 1 shows the
extent of the network in coastal waters around the world. Not shown in the Figure, but also a
valuable source of information, are extensive arrays of receivers in various river systems and
estuaries enabling data exchange between marine and fresh water environments.
Figure 1. The Emerging Worldwide Fish Tracking Network
Table 1 summarizes the key characteristics of the existing network:
Various, ranging from a few grams suitable for very small fish
Transmitter Size and (down to 10 grams or less) to larger more powerful versions.
Life Transmitting life in excess of a year, and often extending over a
number of years, is common.
Currently, the number of fish with active transmitters is over 20,000
Number of Tagged Fish
and this number is growing.
Transmitted periodically (typically on the order of once per
All transmitters send a unique ID code. Some versions also transmit
Data Content sensor data (depth, temperature and/or acceleration being the most
Data is logged from any transmitter within range (a few hundred
Receiver Data metres to more than a kilometre depending on the particular
In the simplest versions, data is accessed by recovering the receiver.
Data Recovery Other versions support remote communication via satellite or
Table 1. Summary of Network Characteristics
Integrating Tracking Receiver with Ocean Observing Systems
The current and planned infrastructure has two major shortcomings:
1. For many species, knowledge of the nature of open ocean migration is important but, as
can be seen form Figure 1, there is virtually no coverage outside coastal waters.
2. Because of the difficulty, and often impossibility, of researchers obtaining approvals for
surface buoys, the vast majority of receivers are underwater meaning that access to data,
either by recovery of the receiver itself or acoustic upload, is infrequent, time consuming
Integration of a tracking receiver into ocean observing systems now in place addresses both
issues above. Candidate observing systems include various fixed surface buoys, Argo profiling
floats and buoys used in the Global Drifting Program. As each of these programs involves
thousands of buoys and central data collection, such integration would cause the biological data
obtained from existing tagging programs to be greatly increased. Clearly, the coverage of such
receiving sites of opportunity will be much sparser than current coastal receiving arrays which
have been installed at critical points where fish are known to pass. On the other hand, almost all
detections would have major value as has been demonstrated time and time again in the past
when extension of receiving arrays has shown fish migrations far in excess of what had been
previously assumed (see O’Dor, 2009, for example).
While integration details would be different for each type of observing system, they shouldn’t be
onerous. A basic receiver which can be polled for detection data consists of a hydrophone which
is approximately a 16 mm by 16 mm cylinder and a 5 cm by 15 cm printed circuit board which
consumes about 3milliwatts. Higher performance receivers (i.e. more range capability) are
possible if the power budget can be increased.
Future Integrated Tags will Fill in the Data Gaps
Biologging tags of various types have been invaluable for “the collection of habitat utilization,
movement patterns and behaviour of large marine predators” as they move through the ocean
(see Costa, 2009, for example). However, for the large majority of species too small to carry
these tags, one of two compromise approaches is used:
1. Archival Tags which store sensor values in memory with data recovered when and if the
fish is recaptured
2. Acoustic Telemetry Tags as described above which transmits sensor data in real time
Each approach, of course, has its limitations. With Archival Tags, no data is recovered unless the
fish is recaptured while, with Telemetry Tags, no data is available for the time that the tag is not
near a receiver (potentially significant in the case of migrating fish). The Integrated Tag concept
now under development combines the features of both approaches and adds a small acoustic
modem which uploads stored sensor data when in the presence of a compatible receiver (i.e. the
same role as is performed by a satellite transmitter in many biologging tags).
Two capabilities significantly enhance the value of this type of tag:
1. Geolocation calculates rough geographic position based on data from on board light,
temperature and depth sensors
2. Business Card Sensor is essentially a miniature acoustic receiver within the tag which
logs the ID code of any other fish which comes within range.
While these sensors are not feasible for the smallest acoustic tag, tags will be significantly
smaller than biologging tags permitting them to be used on fish weighing on the order of one
kilogram or more. Versions of Integrated Tags without one or both of these capabilities also have
the potential to deliver more useful data than is currently possible and would be usable on
The integration of acoustic telemetry receivers into existing and future ocean observing systems
and the development of Integrated Tags of various types will provide a great deal more data from
existing tagging programs as well as create additional new types of data which to date have only
been obtainable from fish large enough to carry biologging tags or which are likely to be
recaptured making the use of archival tags realistic. Figure 2 shows how this information comes
together and how increasing any “dimension” – number of simple or integrated tags, number of
dedicated receivers, receivers integrated with ocean observatories or mobile receivers – creates
the potential for higher quality data on where fish went, what they experienced and their
interaction with other fish.
Global Tracking Database
Current Data Enhancements through Current Development
ID and sensor data for each and Proposed Collaborations
tagged fish for times the tag Significant increase in number of receiving sites
is within range of receivers including open ocean detections
Position accuracy a few A growing database of fish interactions and
hundred metres (normal) or movements from detections by Business Card
a few metres with Sensors in fish or biologging tags attached to
positioning arrays Pelagic fish or Marine Mammals
Opportunities to collect data archives (sensors,
geopositioning) from much smaller fish than
biologging tags require without recapturing
Current Receivers Potential Business
Standalone integrated with Card Sensors
Receivers fixed Ocean Integrated into
(>15,000 today) Observing Buoys Biologging Tags
(Argo, GDP, etc.)
to any compatible Detectable by any Receiver
Detectable by any Receiver
Receiver within within range
ID and Current Current
Value of Sensors Archival Data Value of
(Archive available (Depth, Temp., Sensors
if Tag recovered) Acceleration, IDs of
Archival Tag with Acoustic
Archival Tag (some with
Modem (some with
Business Card Sensor)
Business Card Sensor)
Detectable by any Receiver or Legend
Business Card Sensor within range
Existing Tags usable to fish as small as 10 grams
Tags in development suitable for fish down to
about 1 kg
Current capability supported by Biological
Potential capability in collaboration with Ocean
Current Telemetry Tags Observing System Community
(>20,000 active and
growing) Potential capability in collaboration with Biologging
Figure 2. Global Tracking Database enhancements provided by integration of
tracking receivers into Ocean Observatory Systems and Integrated Tag development
Costa, D.P. (2009) TOPP as a Marine Life Observatory: Using Electronic tags to monitor the
movements, behaviour and habitats of marine vertebrates. Community White Paper
OceanObs’09. Ocean Observing 2009
Heupel, M. R., J. M. Semmens and A. J. Hobday (2006). Automated acoustic tracking of aquatic
animals: scales, design and deployment of listening station arrays. Marine and Freshwater
Research 57(1): 1-13.
Lacroix, G.L., and Voegeli, F. A. 2000. Development of automated monitoring systems for
ultrasonic transmitters. In Advances in fish telemetry. Edited by A. Moore and I. Russell.
CEFAS, Lowestoft. pp. 37-50.
O’dor, Ron (2009) The Ocean Tracking Network. Community White Paper OceanObs’09.
Ocean Observing 2009