Acoustic Telemetry Tagging Hillary Sinnott SCM 330 March 12, 2008 Hillary Sinnott SCM 330 March 12, 2008

Introduction  Acoustic Telemetry Tagging is used in the ocean to obtain a continuous record of the movement of fish  Its very useful in answering specific, fine- scale questions about the physiology and environment of marine life  It can be conducted two ways, actively and passively using digital tags involving hydrophones, GPS systems and different sensor technology  Acoustic Telemetry Tagging is used in the ocean to obtain a continuous record of the movement of fish  Its very useful in answering specific, fine- scale questions about the physiology and environment of marine life  It can be conducted two ways, actively and passively using digital tags involving hydrophones, GPS systems and different sensor technology

Introduction  For both passive and active tagging technology the first step is to attach a “pinger” or acoustic transmitter to a fish  The “pinger” sets off an acoustic pulse of a frequency of about KHZ  The pulse is then picked up from a hydrophone near by  For both passive and active tagging technology the first step is to attach a “pinger” or acoustic transmitter to a fish  The “pinger” sets off an acoustic pulse of a frequency of about KHZ  The pulse is then picked up from a hydrophone near by

Passive Telemetry  Uses a listening station where a hydrophone is mounted  Detects any tagged fish within its range of about m and logs the occurrence of these fish  Range of detection is dependent on the output power of the tags and the frequency of the transducer  Common for islands, bays and submarine canyons to use more than one listening station to detect the number and type of fish that travel in the area  Uses a listening station where a hydrophone is mounted  Detects any tagged fish within its range of about m and logs the occurrence of these fish  Range of detection is dependent on the output power of the tags and the frequency of the transducer  Common for islands, bays and submarine canyons to use more than one listening station to detect the number and type of fish that travel in the area

Hydrophone Arrays  Consists of at least 3 hydrophones  Can be towed behind a ship or placed on the sea floor  Sounds of an animal are received by the hydrophones at different times because the hydrophones are at different distances away from the animal  The “time-of-arrival” of the sound can give information about the distance and direction of the animal  Consists of at least 3 hydrophones  Can be towed behind a ship or placed on the sea floor  Sounds of an animal are received by the hydrophones at different times because the hydrophones are at different distances away from the animal  The “time-of-arrival” of the sound can give information about the distance and direction of the animal

Hydrophone Arrays

Passive Telemetry  Range in complexity  Some collect extensive data from tags while others simply record when a certain ID tag has been detected  A tag may provide a date and time of detection as well as its depth in the water column  Range in complexity  Some collect extensive data from tags while others simply record when a certain ID tag has been detected  A tag may provide a date and time of detection as well as its depth in the water column

Advantages of Passive Systems  Listening stations used for a long period of time  Certain areas can be monitored for years without disruption  General location of a number of individual fish can be monitored and documented at one time  Listening stations used for a long period of time  Certain areas can be monitored for years without disruption  General location of a number of individual fish can be monitored and documented at one time

Disadvantages of Passive Systems  Precise location of fish is very difficult to determine without a complex 3-D system  If a tagged fish leaves the covered area it is impossible to detect  Precise location of fish is very difficult to determine without a complex 3-D system  If a tagged fish leaves the covered area it is impossible to detect

Active Telemetry  The Active method is in real time  A hydrophone is mounted to a tracking vessel  A sound is released by a sonic transmitter and is then used to follow the fish  Intensity of the signal indicates the distance between the fish and the boat  The Active method is in real time  A hydrophone is mounted to a tracking vessel  A sound is released by a sonic transmitter and is then used to follow the fish  Intensity of the signal indicates the distance between the fish and the boat

Advantages of Active Systems  The exact path of the fish through the water can be obtained by a tracking vessel  Other information about the fish and its environment can be encoded by the transmitter  The depth of the water, the waters temperature, the heart rate and tail frequency of the fish and its compass heading can all be accurately recorded  The exact path of the fish through the water can be obtained by a tracking vessel  Other information about the fish and its environment can be encoded by the transmitter  The depth of the water, the waters temperature, the heart rate and tail frequency of the fish and its compass heading can all be accurately recorded

Advantages of Active Systems  Method can always know the exact location of a fish  When more sensors are added additional information about the animal and its environment may be discovered  Oxygen concentration of the water  Prey abundance  Interactions between the species and other marine life  Method can always know the exact location of a fish  When more sensors are added additional information about the animal and its environment may be discovered  Oxygen concentration of the water  Prey abundance  Interactions between the species and other marine life

Disadvantages of Active Systems  Requires the labor of a crew  Used over a short period of time, from a number of hours to just a few days  Tracking ability is dependent on the endurance of the crew and the sea conditions  Adjustment period of about 4-24 hours for the fish after observation  Requires the labor of a crew  Used over a short period of time, from a number of hours to just a few days  Tracking ability is dependent on the endurance of the crew and the sea conditions  Adjustment period of about 4-24 hours for the fish after observation

Active Study  Conducted by the Pfleger Institute of Environmental Research (PIER)  Striped Marlin  Movement patterns, stock structure and habitat preference of the species are not well understood  The large and active fish is a prime target for sport fishing and populations near Latin America, New Zealand and Australia have begun to decline in number  Conducted by the Pfleger Institute of Environmental Research (PIER)  Striped Marlin  Movement patterns, stock structure and habitat preference of the species are not well understood  The large and active fish is a prime target for sport fishing and populations near Latin America, New Zealand and Australia have begun to decline in number

Active Study  Since 2000, over 100 pop-up satellite sensor tags have been deployed off the coast of Mexico to find answers  Since deployment sensors have received data leading researchers to focus on day and night activity differences, temperature preferences and diving migration patterns of the Striped Marlin  Since 2000, over 100 pop-up satellite sensor tags have been deployed off the coast of Mexico to find answers  Since deployment sensors have received data leading researchers to focus on day and night activity differences, temperature preferences and diving migration patterns of the Striped Marlin

Pop-Up Satellite Sensor Tags

 These tags are small devices that represent a combination of archival tags and a satellite transmitter. The tag is inserted with a barb beneath the skin near the base of the dorsal fin, while the tag itself stays outside the animal.

Passive Study  Published in the Journal of Environmental Biology of Fishes  Blacktip Sharks  Examined sharks within a coastal nursery to define how individual animals use the habitats during the summer months  A number of acoustic hydrophones were used to monitor the movement patterns of the sharks over 167 days  Published in the Journal of Environmental Biology of Fishes  Blacktip Sharks  Examined sharks within a coastal nursery to define how individual animals use the habitats during the summer months  A number of acoustic hydrophones were used to monitor the movement patterns of the sharks over 167 days

Passive Study  Study focused on each animal’s utilization of space and core area within the nursery as well as the length of the sharks excursions out of the nursery  The analyzed data concludes that each shark had a small core area and underwent a “homerange” expansion in the month of July  Also, young sharks remain in the nursery up to six months suggesting that nursery protection is critical to young sharks  Study focused on each animal’s utilization of space and core area within the nursery as well as the length of the sharks excursions out of the nursery  The analyzed data concludes that each shark had a small core area and underwent a “homerange” expansion in the month of July  Also, young sharks remain in the nursery up to six months suggesting that nursery protection is critical to young sharks

Conclusion  Passive and Active Telemetry Tagging helps us better understand the behavior of marine life as well as their habitats