Movements and habitat use by PIT‐tagged Atlantic salmon parr in early winter: the influence of anchor ice

Abstract

1. Movements and habitat use by Atlantic salmon parr in Catamaran Brook, New Brunswick, were studied using Passive Integrated Transponder technology. The fish were tagged in the summer of 1999, and a portable reading system was used to collect data on individual positions within a riffle-pool sequence in the early winter of 1999. Two major freezing events occurred on November 11-12 (Ice 1) and November 18-19 (Ice 2) that generated significant accumulations of anchor ice in the riffle. 2. Individually tagged parr (fork length 8.4-12.6 cm, n ¼ 15) were tracked from 8 to 24 November 1999. Over this period, emigration (40%) was higher from the pool than from the riffle. Of the nine parr that were consistently located, seven parr moved <5 m up-or downstream, and two parr moved more than 10 m (maximum 23 m). Parr moved significantly more by night than by day, and diel habitat shifts were more pronounced in the pool with some of the fish moving closer to the bank at night. 3. During Ice 2, there was relatively little movement by most of the parr in the riffle beneath anchor ice up to 10 cm in thickness. Water temperature was 0.16°C above the freezing point beneath anchor ice, suggesting the existence of suitable habitats where salmon parr can avoid supercooling conditions and where they can have access to low velocity shelters. To our knowledge, these are the first data on habitat use by Atlantic salmon parr under anchor ice.

Tracking animals in freshwater with electronic tags: past, present and future

“…Conductivity presumably also influences PIT system performance [45] Compared with radio, acoustic performance is relatively unaffected by high conductivity [33,46] Can use CARTs [22] Abiotic Salinity Saline environments have very high conductivity and make VHF and HF telemetry unusable (as above)…”

Effects of artificial woody structures on Atlantic salmon habitat and populations in a Nova Scotia stream

“…The presence of larger, and presumably more dominant, fish closer to our logs suggests they may be taking advantage of positions with more drifting invertebrates as food. Also, since Brierly Brook freezes in the winter, juvenile salmonids may use the deeper water and cobble stones as refuge from ice (Cunjak and Randall, 1993;Roussel et al, 2004). More work is needed to see how parr respond to the habitat changes caused by our structures and to elucidate the importance of each of these changes.…”

Mobility and home-range use of Atlantic salmon parr over short time scales

“…In comparison to earlier studies using mark-recapture (Saunders and Gee 1964;Hesthagen 1990), visual observation (Steingrimsson and Grant 1999) or passive integrated transponder (PIT) technology Roussel et al 2000Roussel et al , 2004, radiotelemetry permitted locating fish over larger distances under a wider variety of environmental conditions. However, due to the transmitter size limitations, this methodology allows only the study of larger individual parr.…”