Behavioural response of Sea Lamprey (Petromyzon marinus) to acoustic stimuli in a small stream

Sea lamprey are invasive in the Laurentian Great Lakes and parasitically feed on valued fishes. Migration barriers and selective pesticides are used to control sea lamprey, but there is a desire to develop additional control tools such as traps with non-physical deterrents. Sound has been used as a deterrent for other invasive species but its potential for manipulating sea lamprey behavior in natural stream conditions remains untested. Here, behavioral responses of upstream migrating adult sea lamprey in response to low frequency sounds of 70 or 90 Hz was tracked in a small stream (8 m wide) using passive integrated transponder (PIT) telemetry. The low frequency sounds shifted sea lamprey distribution with up to 30% more sea lamprey detected on PIT antennas without sound compared to PIT antennas with sound playing. Future studies could continue testing low frequency sounds in larger rivers with larger speakers for use as a natural deterrent at sea lamprey barriers to push sea lamprey toward traps.

Long-toed Salamander (Ambystoma macrodactylum) hibernacula in Waterton Lakes National Park revealed using Passive Integrated Transponder telemetry

Long-toed Salamanders (Ambystoma macrodactylum) spend most of their lives on land; however, their fossorial nature makes studying their use of habitat difficult. Using Passive Integrated Transponder (PIT) telemetry over two years, we found and characterized nine overwintering sites of Long-toed Salamanders in the vicinity of Linnet Lake and Stable Pond in Waterton Lakes National Park, excavating five of them. These sites were typically associated with stumps and decaying root systems that gave the salamanders access to deep subterranean hibernacula. Overwintering sites were located up to 168 m from the shores of breeding ponds. Given the importance of such terrestrial sites to these populations of Long-toed Salamanders, it is vital that conservation efforts include the preservation of these features and ensure that a sufficient area surrounding breeding ponds remains undisturbed.

Utilization of pit telemetry to assess microhabitat affinities of stream-dwelling female crayfish during reproductive seclusion

Stream habitat-use of female crayfish during brooding of eggs and hatchlings is a poorly studied aspect of crayfish life history and ecology. Our goal was to use passive integrated transponder (PIT) technology to describe diurnal habitat-use patterns of females of two crayfish species during reproductive seclusion. PIT tags were externally attached to female Cambarus friaufi in Pine Creek, Tennessee, USA and Orconectes meeki meeki in Rock Creek, Missouri, USA. Crayfish were tracked with a portable detector and habitatuse was assessed in 2008 for C. friaufi and 2009 for O. m. meeki. PIT tags proved to be a highly effective tool for relocating crayfish, with = 85% of tagged individuals located at least once. Substrate roughness was identified as the most important variable for both species during brooding, followed by additional substrate-related variables, water velocity, and water depth. Cambarus friaufi, however, was more of a generalist and used microhabitat variables in close proportion to availability, whereas O. m. meeki showed more specialized use of brooding habitat variables. Our results suggest that female crayfish reproductive seclusion is closely linked to sufficiently heterogeneous substrate. Reductions in substrate quality could potentially alter crayfish reproductive capacity, thus impacting biodiversity and productivity of streams.

Portable PIT detector as a new tool for non-disruptively locating individually tagged amphibians in the field: a case study with Pyrenean brook salamanders (Calotriton asper)

Passive Integrated Transponder (PIT) telemetry has recently been adapted for locating PIT-tagged fish in shallow waters using portable detectors. In the present study, we tested this method for adult amphibians (Pyrenean brook salamanders, Calotriton asper) PIT-tagged with 12-mm transponders in a headwater rocky stream. PIT telemetry performances were compared with a conventional hand-capture method, i.e. visual searching and overturning movable stones in the streambed. The mean efficiency of the portable detector (88.2% ± 5.2, s.e.) was significantly higher than hand-capture (51.1% ± 6.4) and the operator progressed, on average, four times faster. Time efficiencies were, on average, 0.92 (±0.15) and 0.12 (±0.04) adult salamanders per minute with the portable detector and by hand-capture, respectively. The efficiency of the portable detector was negatively correlated with the percentage of large stones on the streambed. The time needed to prospect a section was positively correlated with the abundance of PIT-tagged adult salamanders, spring inlets and undercut banks. Because PIT telemetry is less disruptive than hand-capture for both salamanders and their habitat, it is a promising and non-disruptive method for developing studies on the ecology and management of amphibians in shallow waters.