Third Level Assessment– Aquatic and Riparian Habitat
Striped Bass & American eels
Striped Bass & Atlantic Eels
Striped bass have been detected only at one location in the Pollett, a short distance above its confluence with the main stem of the Peticodiac (Figure 8). While the causeway gates were closed, striped bass were excluded from the Petitcodiac upstream of Moncton (Locke et al. 2003). Like salmon, striped bass are anadromous, however, though they use the upper estuary and lower freshwater reaches of the Petitcodiac River as nursery habitat in which juveniles feed, mature bass are not known to spawn there (AMEC, 2005). The nearest spawning river is the Stewiacke in Nova Scotia (DFO, 2010a).
The gates were opened in 2010, and by 2011 striped bass were being detected by the trap FFHR operates at the head-of-tide in Salisbury. Genetic analysis of tissue collected at the FNT during the 2013 field season confirmed their ancestry (Mazerolle, 2014). These fish are expanding their nursery range into habitat upstream of the causeway, an area they had historically occupied prior to construction of the causeway in 1968. In August 2022, multiple 40+ cm striped bass were observed during a snorkle survey of the Pollett River. These, which was the same pool a short distance upstream of the confluence of the Pollett with the main stem of the Petitcodiac where they had previously been seen at approximately the same time of year in 2018, 2019, and 2020. The only year out of the last five when striped bass were not seen at that location was 2021 when a seal was observed in that pool. It is likely that the seal may have dispersed or eaten any striped bass it found there that year. It is noteworthy that this location (Figure 8a) is upstream of several salmon redd sites (Figure 7), and so striped bass are clearly now accessing salmon spawning habitat on the Pollett- with potential to prey on juvenile salmon.
Several anglers have independently reported catching striped bass on the main stem of the Petitcodiac as far upstream as the Village of Petitcodiac. Despite minor differences between 2021 and 2022, striped bass have made a strong return to the Petitcodiac, aided in part by the new channel under the bridge.
American eels were encountered at numerous sites (Figure 8a) the full length of the Pollett. Eels have been seen while electrofishing, in the Rotary Screw Trap (RST), and in Mechanic Lake at the very top of the Pollett – in eel pots. While the causeway gates were closed on the Petitcodiac, eels had more success than salmon or striped bass navigating the fishway and accessing the upper reaches of the river. Being catadromous, instead of anadromous like salmon, the eel population was less vulnerable to extirpation as they are not dependent upon consistently accessing a river to perpetuate future generations within that river. Instead, their spawning takes place in the Sargasso Sea, and young eels arrive at and reside in different rivers than those in which their parents had lived (COSEWIC, 2006b). This allowed for a steady stream of incoming eels, arriving to colonize the river anew each generation. The fact they are found at the very top of the Pollett in Mechanic Lake indicates that they can be assumed to be at least periodically present at any location downstream of that point. This suggests that eels have access to the entire Pollett watershed, which despite Gordon Falls is not surprising given the ability of this species to spend extended periods of time out of water while navigating overland around barriers (Van Den Avyle 1984), as well as the ability of juveniles to climb damp vertical surfaces.
