A shift from target species to ecosystem restoration has generated interest in developing fishways that are capable of passing entire fish communities. Although a number of multispecies fishways now exist in North America, evaluations of these fishways are lacking. We used a passive integrated transponder antenna array to quantify passage success and passage duration of fish using a vertical slot fishway (85 m in length, 2.65 m elevation rise, 12 regular pools and 2 turning basins) at a low head dam on the Richelieu River in Quebec, Canada. Fourteen of the 18 tagged species re-ascended the fishway, and passage efficiency was highly variable among species (range 25%-100%); however, it was >50% for five of the species well represented in this study (n > 10) (Atlantic salmon, channel catfish, smallmouth bass, walleye and white sucker). Passage duration was likewise highly variable both among and within species (e.g. 1.0-452.9 h for smallmouth bass, 2.4-237.5 h for shorthead redhorse). Although this fishway design was not uniformly successful in passing fish of all species, this study does reveal the species that have problems with ascent and provides an estimate on the time spent in the fishway that is an important component of passage delay. Such information could be used to inform future design refinements to facilitate passage of the entire assemblage with minimal delay.

We compared detection efficiency for three lengths (12, 23 and 32 mm) of half‐duplex (HDX) passive integrated transponder (PIT) tags for both manual tracking and fixed array applications. In a stream we used a wand‐type manual tracking antenna and determined that detection efficiency was considerably influenced by tag size (i.e., 20% for 12 mm, 43% for 23 mm, and 81% for 32 mm) and water depth. Vertical and horizontal read range also varied among tag sizes (lower for smaller tags) and orientation (12‐mm and 23‐mm tags oriented perpendicularly failed to read in the horizontal test). Using a fixed PIT array, we also compared the detection efficiency of the same three sizes of PIT tags in Shorthead Redhorse Moxostoma macrolepidotum released into a fishway. Again, detection efficiency increased with tag size: 12 mm = 55.8 ± 9.2% (mean ± SE), 23 mm = 91.0 ± 1.8%, and 32 mm = 97.0 ± 1.5%. When using PIT telemetry on smaller fish species and/or life stages, we suggest that researchers consider the tag size, as the diminished detection efficiency of 12‐mm tags could introduce a bias and impede the ability to address some research questions. Received July 11, 2012; accepted September 20, 2012

Few studies have been conducted to evaluate the effectiveness of nature‐like fishways, particularly in low gradient warmwater streams with diverse fish communities. We evaluated a nature‐like fishway that was installed to facilitate upstream passage at a low head dam on Indian Creek near Spencerville, Ontario, Canada. A passive integrated transponder (PIT) array was used to quantify attraction and passage efficiency for 391 PIT tagged warmwater fish, represented by seven species. Attraction efficiency for the three most common species, common shiner (Luxilus cornutus), creek chub (Semotilus atromaculatus) and white sucker (Catostomus commersonii), was 63.3%, 83.7% and 65.6%, respectively, and passage efficiencies were 5.1%, 38.4% and 25%, respectively. Creek chub were able to locate the fishway in less time than white sucker and common shiner; however, took longer to successfully pass. Manipulation of creek chub release locations was used to separate issues of attraction and passage and revealed that passage efficiency was highest (76.2%) for those released within the fishway and intermediate for those released at the entrance (42.1%). This multispecies fishway improved stream connectivity, but additional work is needed to fine tune its configuration. Similar projects that engage stakeholders in nature‐like fishway construction are a promising approach for the thousands of small dams that occur on low gradient streams around the globe, but those studies should incorporate a biological evaluation to ensure that attraction and passage efficiency are optimised.

No abstract

The consequences of stress on the behaviour of wild creek chub Semotilus atromaculatus outside the reproductive period were studied using a single intra-coelomic injection of cortisol, suspended in coconut butter, to experimentally raise plasma cortisol levels. Behaviour between cortisol-treated, sham-treated (injected with coconut butter) and control S. atromaculatus was compared in a mesocosm system, using a passive integrated transponder array, and in a natural stream system (excluding shams), using surgically implanted radio transmitters. While laboratory time-course studies revealed that the cortisol injection provided a physiologically relevant challenge, causing prolonged (c. 3 days) elevations of plasma cortisol similar to that achieved with a standardized chasing protocol, no differences in fine-scale movements were observed between cortisol-treated, sham-treated and control S. atromaculatus nor in the large-scale movements of cortisol-treated and control S. atromaculatus. Moreover, no differences were observed in diel activity patterns among treatments. Differential mortality, however, occurred starting 10 days after treatment where cortisol-treated S. atromaculatus exhibited nearly twice as many mortalities as shams and controls. These results suggest that, although the experimental manipulation of cortisol titres was sufficient to cause mortality in some individuals, there were compensatory mechanisms that maintained behaviours (i.e. including activity and movement) prior to death. This study is one of the first to use experimental cortisol implants outside a laboratory environment and during the non-reproductive period and yields insight into how wild animals respond to additional challenges (in this case elevated cortisol) using ecologically meaningful endpoints.