10 Search Results

Insufficient service life and the resulting need for battery replacements have been a great challenge for implantable electronic devices. This is particularly true for animal tracking applications, because recapturing animals is often unlikely once they are released to the wild. To tackle this problem, we developed a biomechanical energy harvester that uses a Macro Fiber Composite™ (MFC) piezoelectric beam to harvest the mechanical energy from animals’ body bending movements as the power source for implantable and wearable devices. Prototypes of an underwater acoustic transmitter using this technology were subdermally implanted into juvenile white sturgeon and their energy harvesting performance wasmore » evaluated through the device’s transmissions. Additionally, the fish successfully recovered from the implantation surgery and freely swam inside a tank. The transmitter prototypes in the fish continually transmitted signals for a period up to 5 weeks. A benchtop test setup was also created to emulate the fish’s body bending, estimate the device’s energy harvesting performance in the live fish, and perform accelerated fatigue testing of the energy harvester by applying test parameters learned from a video study of the fish’s body movement and behavior characteristics. The gradual depolarization of the piezoelectric ceramic material in the MFC under cyclic mechanical loading was the main limiting factor for the life span of the energy harvester. Pathways for improvement are proposed to achieve long-term efficacy of powering implantable and wearable electronic devices.« less

During downstream passage of hydroelectric facilities, fish can be injured by rapid decompression; this is especially noted during hydroturbine passage. The rapid decrease in pressure can cause barotrauma as undissolved gas expands according to Boyle’s law. However, it is difficult to see barotrauma occurring within the body of the fish in real time. In order to determine if transparent fish could provide greater insight into barotrauma, five species of transparent tropical fish were exposed to rapid decompressions so internal injuries could be viewed noninvasively. Before and after photos were taken to review the injuries and high speed video allowed observationsmore » of barotrauma pathways in vivo. High speed video recordings show the expansion of the swim bladder and subsequent release of gas through the mouth and gills, and into the body cavity when the swim bladder ruptured. Post-decompression photographs show that many internal injuries were visible and included hemorrhaging and the presence of emphysema within the body cavity and tissues. These observations provide new opportunities to understand the pathways and effects of barotrauma.« less

The current minimum size for tagging Chinook Salmon Oncorhynchus tshawytscha with acoustic transmitters is = 95 mm fork length (FL). Using a new injectable acoustic transmitter (AT), our objective was to determine a minimum size for tagging Chinook Salmon. We measured survival and transmitter and tissue retention after exposure to rapid pressure changes (n = 399) or shear forces (n = 308). Fish (69–107 mm FL) were implanted with an AT (0.22 g; AT-only) or an AT and a passive integrated transponder (PIT; 0.10 g; AT+PIT) tag through a 3-mm incision with no sutures, or did not receive an incisionmore » or tag (control). Survival and transmitter and tissue retention following pressure changes was significantly lower for AT-only (0.70) and AT+PIT (0.54) fish compared to controls (0.85). No transmitters were expelled but 2.2% of AT-only and 12.5% of AT+PIT fish had tissue or a transmitter protruding. Following shear exposure, survival and transmitter and tissue retention was significantly lower for AT-only (0.70) and AT+PIT (0.61) fish compared to controls (0.98). Here, tissue expulsion described 87% of AT-only and 80% of AT+PIT mortalities. In both tests fish larger than 85–88 mm FL had a higher probability of survival and tissue and transmitter retention than smaller fish. We recommend the minimum size for tagging continue to be 95 mm FL, using a 3-mm incision with no sutures.« less

To acquire 3-D tracking data on juvenile salmonids, Juvenile Salmon Acoustic Telemetry System (JSATS) cabled hydrophone arrays were deployed in the forebays of two dams on the Snake River and at a mid-reach reservoir between the dams. The depth distributions of fish were estimated by statistical analyses performed on large 3-D tracking data sets from ~33,500 individual acoustic tagged yearling and subyearling Chinook salmon and juvenile steelhead at the two dams in 2012 and subyearling Chinook salmon at the two dams and the mid-reach reservoir in 2013. This research investigated the correlation between vertical migration behavior and passage routes. Themore » depth distributions of fish within the forebays of the dams were significantly different from fish passing the mid-reach reservoir. Fish residing deeper in the forebay tended to pass the dam using deeper powerhouse routes. This difference in depth distributions indicated that the depth distribution of fish at the mid-reach reservoir was not related to behaviors of fish passing through certain routes of the adjacent dams. For fish that were detected deeper than 17.5 m in the forebays, the probability of powerhouse passage (i.e., turbine) increased significantly. Another important finding was the variation in depth distributions during dam passage associated with the diel period, especially the crepuscular periods.« less

Little is known about the three-dimensional depth distributions in rivers of individually marked fish that are in close proximity to hydropower facilities. Knowledge of the depth distributions of fish approaching dams can be used to understand how vulnerable fish are to injuries such as barotrauma as they pass through dams. To predict the possibility of barotrauma injury caused by pressure changes during turbine passage, it is necessary to understand fish behaviour relative to acclimation depth in dam forebays as they approach turbines. A guiding study was conducted using high-resolution three-dimensional tracking results of salmonids implanted with Juvenile Salmon Acoustic Telemetrymore » System transmitters to investigate the depth distributions of subyearling and yearling Chinook salmon ( Oncorhynchus tshawytscha ) and juvenile steelhead ( Oncorhynchus mykiss ) passing two dams on the Snake River in Washington State. Multiple approaches were evaluated to describe the depth at which fish were acclimated, and statistical analyses were performed on large data sets extracted from ~28 000 individually tagged fish during 2012 and 2013. Our study identified patterns of depth distributions of juvenile salmonids in forebays prior to passage through turbines or juvenile bypass systems. This research indicates that the median depth at which juvenile salmonids approached turbines ranged from 2.8 to 12.2 m, with the depths varying by species/life history, year, location (which dam) and diel period (between day and night). One of the most enlightening findings was the difference in dam passage associated with the diel period. The amount of time that turbine-passed fish spent in the immediate forebay prior to entering the powerhouse was much lower during the night than during the day. This research will allow scientists to understand turbine-passage survival better and enable them to assess more accurately the effects of dam passage on juvenile salmon survival.« less

Turbine-passed fish are exposed to rapid decreases in pressure which can cause barotrauma. The presence of an implanted telemetry tag increases the likelihood of injury or death from exposure to pressure changes, thus potentially biasing studies evaluating survival of turbine-passed fish. Therefore, a neutrally buoyant externally attached tag was developed to eliminate this bias in turbine passage studies. This new tag was designed not to add excess mass in water or take up space in the coelom, having an effective tag burden of zero with the goal of reducing pressure related biases to turbine survival studies. To determine if thismore » new tag affects fish performance or susceptibility to predation, it was evaluated in the field relative to internally implanted acoustic transmitters (JSATS; Juvenile Salmon Acoustic Telemetry System) used widely for survival studies of juvenile salmonids. Survival and travel time through the study reach was compared between fish with either tag type in an area of high predation in the Snake and Columbia rivers, Washington. An additional group of fish affixed with neutrally-buoyant dummy external tags were implanted with passive integrated transponder (PIT) tags and recovered further downstream to assess external tag retention and injury. There were no significant differences in survival to the first detection site, 12 river kilometers (rkm) downstream of release. Travel times were also similar between groups. Conversely, externally-tagged fish had reduced survival (or elevated tag loss) to the second detection site, 65 rkm downstream. In addition, the retention study revealed that tag loss was first observed in fish recaptured approximately 9 days after release. Results suggest that this new tag may be viable for short term (<8 days) single-dam turbine-passage studies and under these situations, may alleviate the turbine passage-related bias encountered when using internal tags, however further research is needed to confirm this.« less

Abstract A substantial percentage of the Pacific salmon Oncorhynchus spp. and steelhead O. mykiss smolts that emigrate to the ocean each year are smaller than 110 mm (fork length). However, relatively few researchers have implanted acoustic transmitters in fish of this size, and none have reported minimum fish lengths below 110 mm for which the tag burden did not negatively influence growth or survival. The influence of a surgically implanted acoustic microtransmitter and a passive integrated transponder (PIT) tag on the growth and survival of hatchery-reared juvenile Chinook salmon was examined over a period of 30 d. Growth and survivalmore » were compared between treatment (tagged) and control (untagged) fish within three size-groups (80–89, 90–99, and 100–109 mm). The acoustic microtransmitter and PIT tag implanted in our study had a combined weight of 0.74 g; the combined tag burden for implanted fish ranged from 4.5% to 15.7%. The results indicated that growth and survival among implanted juvenile Chinook salmon were size dependent. Significant differences in growth rate and survival were observed between treatment and control fish in the 80–89-mm group. The survival of implanted fish smaller than 11.1 g (tag burden, >6.7%) and the growth of fish smaller than 9.0 g (tag burden, >8.2%) were negatively affected by the implantation or presence of an acoustic microtransmitter and PIT tag. The results of this study will aid researchers in determining the minimum fish size suitable for use in acoustic telemetry studies that estimate the short-term (30-d) survival and growth of juvenile salmonids.« less

Abstract A new coded electromyogram (CEMG) transmitter was recently introduced to the market to allow broader application and greater flexibility of configurations than the conventional noncoded version. CEMG transmitters were implanted into 20 steelhead Oncorhynchus mykiss and calibrated to swimming speed in a respirometer to determine the relationship between swimming speed and the output of the transmitters and also to determine how the output of a single transmitter varied when implanted in multiple fish. Linear regression models showed a strong positive relationship between the output from CEMG transmitters and swimming speed. However, grouping signals from multiple transmitters produced a lessmore » accurate relationship between CEMG output and swimming speed than using signals from individual transmitters. The results, therefore, do not suggest that the CEMG transmitters acted similarly in all fish. Calibration data from one transmitter were not readily transferable among multiple fish implanted with the same transmitter, suggesting that the same transmitter implanted in multiple fish also performed dissimilarly. These results indicate that experimental designs that require more precise estimates of muscular activity should use individual fish–CEMG transmitter calibrations. Variation in fish length, fish weight, location of transmitter implantation (distance from snout), and distance between the electrode tips did not account for the variation in models. The smaller size of the new CEMG transmitters will allow them to be used in a larger range of fish species and sizes. The fact that the transmitter has a coded transmission reduces the likelihood of interference from outside signals and allows multiple fish to be continuously logged on a single receiver. This could lead to reduced project costs because fewer receivers may be needed. However, one downfall of this new transmitter is that it has a smaller range of output, which may lead to lower accuracy in estimating swimming speeds.« less

Abstract Maturing female anadromous salmonids receiving intraperitoneally implanted telemetry transmitters (tags) may experience difficulty depositing eggs during natural spawning. We allocated maturing adult female steelhead Oncorhynchus mykiss to three treatment groups: (1) fish whose tags were surgically implanted in the body cavity (internal), (2) fish whose tags were implanted between the skin and muscle tissue (subdermal), and (3) nontagged fish. The steelhead were then allowed to spawn in an experimental channel. Internally tagged females retained significantly more eggs than did the subdermally tagged and nontagged control groups; subdermally tagged and nontagged control fish did not differ significantly. Females in themore » internally tagged, subdermally tagged, and nontagged groups retained an average of 49, 11, and 2% of their eggs, respectively. The onset of sexual activity did not differ significantly among treatments. Postspawning mortality was 70% for internally and subdermally tagged females and 0% for nontagged females. Each research or monitoring program should weigh the costs associated with transmitter use (where they are known) against the value of information obtained and should carefully evaluate assumptions about transmitter effects. For these reasons, the use of electromyogram electrodes and other telemetry transmitters for monitoring imperiled fish populations should be employed with caution. We suggest that subdermal implantation techniques be considered in future studies during the reproductive period to reduce egg retention caused by internally implanted transmitters.« less