Canadian Journal of Fisheries and Aquatic Sciences, 2008
The performance of an array of data-logging single frequency acoustic receivers in the Caloosahat... more The performance of an array of data-logging single frequency acoustic receivers in the Caloosahatchee River (Florida, USA) was examined and the results incorporated into a positioning algorithm for animals tracked within the system. The mean code detection efficiency across all individual receivers and all download periods was 0.414 detections per synchronization code. On average, the code rejection coefficient was approximately 4%, indicating that it was only a minor factor in reducing code detection efficiency. There were significant performance differences between stations and download periods, but no interaction between these two factors for all three metrics. Code detection efficiency, the rejection coefficient, and the noise quotient all showed significant variations with distance from the river mouth and time since deployment. Comparison of position estimates with and without efficiency produced small differences for bull sharks (Carcharhinus leucas) and cownose rays (Rhinoptera bonasus) monitored via this system. Root mean square errors were higher for cownose rays (48 m) than for bull sharks (23 m). Mean differences for individuals were always slightly downstream because of the increasing code detection efficiency of upriver receivers. The results of this comparison indicated that the inclusion of code detection efficiency did not significantly improve the results of the positioning algorithm.
Elasmobranchs living in rivers and estuaries may be highly susceptible to environmental and anthr... more Elasmobranchs living in rivers and estuaries may be highly susceptible to environmental and anthropogenic changes to coastal habitats. To address this, patterns of movement of 67 juvenile bull sharks (Carcharhinus leucas) were examined in the Caloosahatchee River between 2003 and 2006 using an array of 25 acoustic receivers. Individuals were monitored for periods of 1-460 days with most present for periods of weeks to months. Individuals utilised the entire monitored section of the river (∼27 km) and also moved upriver beyond the extent of the acoustic array. Daily activity spaces of individuals ranged from 0 to 14 km with most <5 km. Monthly mean home ranges were 0.9-5.6 km and although home-range sizes were consistent through time, location of individuals within the river changed through time. Individuals moved upstream during the day and downstream at night and this pattern persisted across years. Based on data collected from depth transmitters in 2006, individuals swam closer to the surface at night and remained in deeper water during the day, suggesting further diurnal patterns in habitat use. Long-term consistent use of this habitat by young C. leucas suggests this population is highly dependent on the Caloosahatchee River as a nursery area.
21 cownose rays Rhinoptera bonasus were tagged and tracked within Pine Island Sound estuary, Flor... more 21 cownose rays Rhinoptera bonasus were tagged and tracked within Pine Island Sound estuary, Florida, using passive acoustic telemetry. Residence time of individuals ranged between 1 and 102 days. No relationship was detected between ray activity and tidal stage or time of day. Minimum convex polygons (MCP) and kernel utilization distributions (KUD) were calculated over several time frames to demonstrate the extent of an animal's home range and core areas of use. Total MCPs ranged between 0Á81 and 71Á78 km 2 (mean ¼ 22Á01 km 2 ), with daily MCPs as large as 25Á8 km 2 . Total 95% KUDs ranged between 0Á18 and 62Á44 km 2 (mean ¼ 22Á63 km 2 ), while total 50% KUDs were smaller, ranging from 0Á09 to 9Á68 km 2 (mean ¼ 3Á33 km 2 ). Both MCP and KUD areas exhibited a positive relationship with residence time and R. bonasus size. As mobile, pelagic swimmers capable of traversing large distances, these data show that cownose rays travel extensively throughout this estuary, yet may remain within very small areas for extended periods.
Passive acoustic telemetry was used to monitor the movements of cownose rays (Rhinoptera bonasus)... more Passive acoustic telemetry was used to monitor the movements of cownose rays (Rhinoptera bonasus) within the Caloosahatchee River estuary in Southwest Florida. Twelve rays were tracked within the river between January 2004 and May 2005 for periods up to 234 days. Linear home range was calculated for all individuals and ranged between 0 and 18.4 km (daily) and 1 and 22.3 km (overall). Ray position within the river was compared to changing water quality parameters throughout the study. Although home range size did not increase with increasing salinity, individ-uals did occur farther upriver with decreasing flow rates and increasing salinity. There were no differences detected between day and night distribution patterns. Movement and presence patterns demonstrated significant use of the estuarine river over all months, indicating that cownose rays in southwest Florida may not undertake long seasonal migrations as established for other parts of their range.
The use of a coastal estuary by bonnethead sharks, Sphyrna tiburo, was examined by acoustic monit... more The use of a coastal estuary by bonnethead sharks, Sphyrna tiburo, was examined by acoustic monitoring, gillnet sampling and tagrecapture studies. Acoustic monitoring data were used to define the residency and movement patterns of sharks within Pine Island Sound, Charlotte Harbor, Florida. Sharks were monitored for periods of 1-173 days with individuals regularly moving in and out of the detection range of the acoustic system. Patterns of movement could not be correlated with tidal level or time of day. Home range sizes within the Pine Island Sound population were typically small with individuals using core areas on a daily basis. However, core areas shifted within the study site over time resulting in eventual usage of most of the available habitat. Gillnet sampling revealed that S. tiburo were abundant in shallow water near seagrass beds, but that presence of individuals at specific sites was variable. Tag-recapture data showed that most individuals remained within the Pine Island Sound region over time and did not appear to undergo long coastal migrations. The movement and residence patterns of S. tiburo suggest that individuals are resident within the estuary, but do not show site fidelity to specific areas within the estuary.
We isolated 40 microsatellite markers for the endangered Atlantic, and Pacific goliath grouper, E... more We isolated 40 microsatellite markers for the endangered Atlantic, and Pacific goliath grouper, Epinephelus itajara and E. quinquefasciatus. Loci were characterized using samples of E. itajara (n = 52) and E. quinquefasciatus (n = 10). Twenty-nine loci were polymorphic. For E. itajara and E. quinquefasciatus, respectively, mean numbers of alleles per locus were 5.2 and 4.3 and mean observed heterozygosities were 0.46 and 0.63. Three loci departed from Hardy-Weinberg equilibrium expectations in the E. itajara sample. Allele frequencies differed significantly between the two taxa for each polymorphic locus.
Canadian Journal of Fisheries and Aquatic Sciences, 2008
The performance of an array of data-logging single frequency acoustic receivers in the Caloosahat... more The performance of an array of data-logging single frequency acoustic receivers in the Caloosahatchee River (Florida, USA) was examined and the results incorporated into a positioning algorithm for animals tracked within the system. The mean code detection efficiency across all individual receivers and all download periods was 0.414 detections per synchronization code. On average, the code rejection coefficient was approximately 4%, indicating that it was only a minor factor in reducing code detection efficiency. There were significant performance differences between stations and download periods, but no interaction between these two factors for all three metrics. Code detection efficiency, the rejection coefficient, and the noise quotient all showed significant variations with distance from the river mouth and time since deployment. Comparison of position estimates with and without efficiency produced small differences for bull sharks (Carcharhinus leucas) and cownose rays (Rhinoptera bonasus) monitored via this system. Root mean square errors were higher for cownose rays (48 m) than for bull sharks (23 m). Mean differences for individuals were always slightly downstream because of the increasing code detection efficiency of upriver receivers. The results of this comparison indicated that the inclusion of code detection efficiency did not significantly improve the results of the positioning algorithm.
Elasmobranchs living in rivers and estuaries may be highly susceptible to environmental and anthr... more Elasmobranchs living in rivers and estuaries may be highly susceptible to environmental and anthropogenic changes to coastal habitats. To address this, patterns of movement of 67 juvenile bull sharks (Carcharhinus leucas) were examined in the Caloosahatchee River between 2003 and 2006 using an array of 25 acoustic receivers. Individuals were monitored for periods of 1-460 days with most present for periods of weeks to months. Individuals utilised the entire monitored section of the river (∼27 km) and also moved upriver beyond the extent of the acoustic array. Daily activity spaces of individuals ranged from 0 to 14 km with most <5 km. Monthly mean home ranges were 0.9-5.6 km and although home-range sizes were consistent through time, location of individuals within the river changed through time. Individuals moved upstream during the day and downstream at night and this pattern persisted across years. Based on data collected from depth transmitters in 2006, individuals swam closer to the surface at night and remained in deeper water during the day, suggesting further diurnal patterns in habitat use. Long-term consistent use of this habitat by young C. leucas suggests this population is highly dependent on the Caloosahatchee River as a nursery area.
21 cownose rays Rhinoptera bonasus were tagged and tracked within Pine Island Sound estuary, Flor... more 21 cownose rays Rhinoptera bonasus were tagged and tracked within Pine Island Sound estuary, Florida, using passive acoustic telemetry. Residence time of individuals ranged between 1 and 102 days. No relationship was detected between ray activity and tidal stage or time of day. Minimum convex polygons (MCP) and kernel utilization distributions (KUD) were calculated over several time frames to demonstrate the extent of an animal's home range and core areas of use. Total MCPs ranged between 0Á81 and 71Á78 km 2 (mean ¼ 22Á01 km 2 ), with daily MCPs as large as 25Á8 km 2 . Total 95% KUDs ranged between 0Á18 and 62Á44 km 2 (mean ¼ 22Á63 km 2 ), while total 50% KUDs were smaller, ranging from 0Á09 to 9Á68 km 2 (mean ¼ 3Á33 km 2 ). Both MCP and KUD areas exhibited a positive relationship with residence time and R. bonasus size. As mobile, pelagic swimmers capable of traversing large distances, these data show that cownose rays travel extensively throughout this estuary, yet may remain within very small areas for extended periods.
Passive acoustic telemetry was used to monitor the movements of cownose rays (Rhinoptera bonasus)... more Passive acoustic telemetry was used to monitor the movements of cownose rays (Rhinoptera bonasus) within the Caloosahatchee River estuary in Southwest Florida. Twelve rays were tracked within the river between January 2004 and May 2005 for periods up to 234 days. Linear home range was calculated for all individuals and ranged between 0 and 18.4 km (daily) and 1 and 22.3 km (overall). Ray position within the river was compared to changing water quality parameters throughout the study. Although home range size did not increase with increasing salinity, individ-uals did occur farther upriver with decreasing flow rates and increasing salinity. There were no differences detected between day and night distribution patterns. Movement and presence patterns demonstrated significant use of the estuarine river over all months, indicating that cownose rays in southwest Florida may not undertake long seasonal migrations as established for other parts of their range.
The use of a coastal estuary by bonnethead sharks, Sphyrna tiburo, was examined by acoustic monit... more The use of a coastal estuary by bonnethead sharks, Sphyrna tiburo, was examined by acoustic monitoring, gillnet sampling and tagrecapture studies. Acoustic monitoring data were used to define the residency and movement patterns of sharks within Pine Island Sound, Charlotte Harbor, Florida. Sharks were monitored for periods of 1-173 days with individuals regularly moving in and out of the detection range of the acoustic system. Patterns of movement could not be correlated with tidal level or time of day. Home range sizes within the Pine Island Sound population were typically small with individuals using core areas on a daily basis. However, core areas shifted within the study site over time resulting in eventual usage of most of the available habitat. Gillnet sampling revealed that S. tiburo were abundant in shallow water near seagrass beds, but that presence of individuals at specific sites was variable. Tag-recapture data showed that most individuals remained within the Pine Island Sound region over time and did not appear to undergo long coastal migrations. The movement and residence patterns of S. tiburo suggest that individuals are resident within the estuary, but do not show site fidelity to specific areas within the estuary.
We isolated 40 microsatellite markers for the endangered Atlantic, and Pacific goliath grouper, E... more We isolated 40 microsatellite markers for the endangered Atlantic, and Pacific goliath grouper, Epinephelus itajara and E. quinquefasciatus. Loci were characterized using samples of E. itajara (n = 52) and E. quinquefasciatus (n = 10). Twenty-nine loci were polymorphic. For E. itajara and E. quinquefasciatus, respectively, mean numbers of alleles per locus were 5.2 and 4.3 and mean observed heterozygosities were 0.46 and 0.63. Three loci departed from Hardy-Weinberg equilibrium expectations in the E. itajara sample. Allele frequencies differed significantly between the two taxa for each polymorphic locus.
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