Density Estimates of Harbour Porpoises Phocoena Phocoena at Eight Coastal Sites in Ireland

2014 ◽  
Vol 114B (1) ◽  
pp. 19-34
Author(s):  
Simon Berrow ◽  
Ronan Hickey ◽  
Ian O'Connor ◽  
David McGrath
Keyword(s):  
Phocoena Phocoena ◽  
Density Estimates

Short Note: A Record of Twin Fetuses in a Harbor Porpoise (Phocoena phocoena) Stranded on the Dutch Coast

2014 ◽  
Vol 40 (4) ◽  
pp. 394-397 ◽  
Author(s):  
Lonneke L. IJsseldijk ◽  
Andrea Gröne ◽  
Sjoukje Hiemstra ◽  
Jeroen Hoekendijk ◽  
Lineke Begeman
Keyword(s):  
Short Note ◽  
Phocoena Phocoena ◽  
Harbor Porpoise ◽  
Dutch Coast

Rehabilitation and Homing Behavior of a Satellite-Tracked Harbor Porpoise (Phocoena phocoena)

2008 ◽  
Vol 34 (1) ◽  
pp. 1-8 ◽  
Author(s):  
David T. Schofield ◽  
Greg Early ◽  
Frederick W. Wenzel ◽  
Keith Matassa ◽  
Cindi Perry ◽  
...  
Keyword(s):  
Phocoena Phocoena ◽  
Harbor Porpoise ◽  
Homing Behavior

Effect of Pile-Driving Playback Sound Level on Fish-Catching Efficiency in Harbor Porpoises (Phocoena phocoena)

2019 ◽  
Vol 45 (4) ◽  
pp. 398-410 ◽  
Author(s):  
Ronald A. Kastelein ◽  
Léonie A. E. Huijser ◽  
Suzanne Cornelisse ◽  
Lean Helder-Hoek ◽  
Nancy Jennings ◽  
...  
Keyword(s):  
Sound Level ◽  
Pile Driving ◽  
Phocoena Phocoena ◽  
Harbor Porpoises

Behavioral Responses of Harbor Porpoises (Phocoena phocoena) to U.S. Navy 53C Sonar Signals in Noise

2019 ◽  
Vol 45 (4) ◽  
pp. 359-366
Author(s):  
Ronald A. Kastelein ◽  
Michael A. Ainslie ◽  
Ruby van Kester
Keyword(s):  
Behavioral Responses ◽  
Phocoena Phocoena ◽  
Harbor Porpoises

Short Note: Predation of Harbour Porpoises (Phocoena phocoena) by Grey Seals (Halichoerus grypus) in Wales

2015 ◽  
Vol 41 (2) ◽  
pp. 188-191 ◽  
Author(s):  
Thomas Stringell ◽  
Dave Hill ◽  
Dafydd Rees ◽  
Ffion Rees ◽  
Padrig Rees ◽  
...  
Keyword(s):  
Short Note ◽  
Halichoerus Grypus ◽  
Phocoena Phocoena

scholarly journals Evaluating Alternative Flight Plans in Thermal Drone Wildlife Surveys—Simulation Study

2021 ◽  
Vol 13 (6) ◽  
pp. 1102
Author(s):  
Julia Witczuk ◽  
Stanisław Pagacz
Keyword(s):  
Computer Simulations ◽  
Survey Design ◽  
Distance Sampling ◽  
Line Of Sight ◽  
Density Estimates ◽  
Accuracy And Precision ◽  
Survey Costs ◽  
Random Survey ◽  
Density Population

The rapidly developing technology of unmanned aerial vehicles (drones) extends to the availability of aerial surveys for wildlife research and management. However, regulations limiting drone operations to visual line of sight (VLOS) seriously affect the design of surveys, as flight paths must be concentrated within small sampling blocks. Such a design is inferior to spatially unrestricted randomized designs available if operations beyond visual line of sight (BVLOS) are allowed. We used computer simulations to assess whether the VLOS rule affects the accuracy and precision of wildlife density estimates derived from drone collected data. We tested two alternative flight plans (VLOS vs. BVLOS) in simulated surveys of low-, medium- and high-density populations of a hypothetical ungulate species with three levels of effort (one to three repetitions). The population density was estimated using the ratio estimate and distance sampling method. The observed differences in the accuracy and precision of estimates from the VLOS and BVLOS surveys were relatively small and negligible. Only in the case of the low-density population (2 ind./100 ha) surveyed once was the VLOS design inferior to BVLOS, delivering biased and less precise estimates. These results show that while the VLOS regulations complicate survey logistics and interfere with random survey design, the quality of derived estimates does not have to be compromised. We advise testing alternative survey variants with the aid of computer simulations to achieve reliable estimates while minimizing survey costs.

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