Browsing by Author "Samways, Kurt M."
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Item An Assessment of Inner Bay of Fundy Atlantic Salmon (Salmo salar) Spawning Success in Fundy National Park(University of New Brunswick, 2023-04) Nason, Jack S. J.; Samways, Kurt M.; Pavey, Scott A.Atlantic salmon (Salmo salar) have declined precipitously throughout most of their North American range. As a result, many strategies have been implemented to try and restore Atlantic salmon (Salmo salar). One such restoration strategy, implemented by the Fundy Salmon Recovery project, involves the collection of endangered inner Bay of Fundy salmon smolts from their natal rivers to be reared at the world’s first marine conservation farm to maturity. This strategy includes both an open net ocean pen and freshwater hatchery components. Upon maturity, these salmon are returned to their natal rivers as adults. This release may be done by hand, by carrying the sexually mature salmon to the water or by carefully lowering them into pools using a helicopter, so they can naturally spawn. In my study, I aim to determine whether these differences in rearing and release strategies led to significant changes in offspring production in the adults of two Fundy National Park rivers. Single nucleotide polymorphisms (SNPs) at 185 loci were used to match parents with the next year’s offspring using Colony, a parentage analysis software. Using a fixed effects linear model, I found that there was no significant effect on offspring production caused by release strategy in both rivers. On the Point Wolfe River, rearing strategy was found to have a significant effect on offspring production – with marine-reared adults out-performing freshwater reared adults. This suggests that the marine-rearing strategy, implemented by the Fundy Salmon Recovery project can outperform, in some cases the more traditional freshwater rearing strategy in terms of releasing high-fitness adult Atlantic salmon.Item Investigating the Life History of Returning iBoF Atlantic Salmon (Salmo salar) using Passive Integrated Transponder (PIT) Technology(University of New Brunswick, 2024-02) Morrissey, Alexandra M.; Samways, Kurt M.Since the 1980s, the inner Bay of Fundy (iBoF) Atlantic salmon (Salmo salar) population has significantly declined, in which it was listed as endangered under the Species at Risk Act (SARA) in 2003. Fundy National Park (FNP) contains critical habitat for this population, including the Upper Salmon and Point Wolfe rivers, in which ongoing recovery efforts are being implemented. This study assesses current restoration strategies by evaluating the life history characteristics of successfully returning Atlantic salmon to FNP. Among the 385 salmon that returned to FNP rivers between 2016-2023, I found that fish reared in modified open net pens in the Bay of Fundy exhibited a return rate 1.59 times greater than fish reared in a traditional hatchery environment and juvenile salmon collected as wild smolt returned at a rate twofold higher than that of wild-exposed parr. It was found that maximizing wild exposure is crucial for the restoration of endangered salmon populations and should be a vital component to consider when captive-rearing fish. These findings allow users to adaptively manage and understand the different strategies currently being implemented by the Fundy Salmon Recovery program.Item Reproductive success of inner Bay of Fundy Atlantic salmon (Salmo salar) exposed to modified feeding regimes(University of New Brunswick, 2024-03) Armstrong, Kristin; Samways, Kurt M.Atlantic salmon (Salmo salar) are widely considered to be at-risk across much of their natural distribution. Reproductive success was investigated for inner Bay of Fundy (iBoF) Atlantic salmon reared from smolt to one sea winter maturity under various feeding regimes. The experiment measured fecundity, egg weight and diameter, and survival to the eyed-stage of development from 13 females and across 39 unique crosses. Fecundity and egg metrics (i.e., egg weight and diameter) did not vary significantly across feeding treatments, however egg mortality was significantly higher in the commercial-style feeding control group (SS4) than any experimental, food-limiting treatment group. Females of treatment group SS5, which experienced the second-most food limitation, produced the greatest number of eggs per centimeter fork length, as well as the lowest mortality rates. The results of this study suggest feeding limitation influences reproductive success in iBoF salmon and inform conservation strategies for the recovery of this species.Item Seasonal and Temporal Variations in the Underwater Vocal Behaviour of Weddell Seals (Leptonychotes weddellii) Near Davis, Antarctica: Insights from Passive Acoustic Monitoring(University of New Brunswick, 2024-04) Simmonds, Emma; Terhune, John M.; Samways, Kurt M.Within the Antarctic environment, marine mammals rely on sound for communication. This study investigated the vocal behaviours of Weddell seals (Leptonychotes weddellii) using passive acoustic monitoring of calls recorded under landfast ice near Davis, Antarctica (68°34'S, 77°58'E), provided by the Australian Antarctic Division (AAD). Vocalizations were examined throughout austral winter and summer. I analyzed hourly data—sampled every ten days from July 24th, 2021, to December 31st, 2021—and recorded the number of calls and elements for eight minutes. Statistical analyses included generalized linear models with a negative binomial distribution. Results show increased vocalizations before dawn and after sunset until 24 hours of sunlight. Furthermore, underwater vocalizations varied across seasons, with high calling rates during winter, low calling rates during breeding season, and a sharp decline in mid-November. These findings produce insights into the vocalization trends of Weddell seals and will be utilized by AAD for environmental impact assessments.Item Tales from the Scales: Investigating the impact of restoration on smolt age class distribution & growth rates in an iBoF Atlantic salmon (Salmo salar) population(University of New Brunswick, 2022-04) Cyr, Lauren P.; Samways, Kurt M.The inner Bay of Fundy (iBoF) Atlantic salmon are a genetically distinct population of Atlantic salmon residing within the Bay of Fundy and northern Gulf of Maine, listed as endangered under the Species at Risk Act. Located in Fundy National Park (FNP), the Upper Salmon River is listed as critical habitat for iBoF salmon and has been the site of several restoration strategies: primarily, release of salmon though traditional (juvenile) and Fundy Salmon Recovery (FSR) models (natural spawning from adult releases). This study aims to evaluate the efficacy of adult releases to maintain a wild-like population, via interpretation of archived smolt scales. Aided by a novel scale-analysis script, I evaluated scales from 1240 individuals collected between 2002-2021 to assess age distributions and annual growth rates of smolt cohorts. I observed a shift towards smolt cohorts with more 2+ and 3+ smolts and increased growth rates, following implementation of FSR release strategies. The results of this study provide insight into the impact of this restoration strategy on annual smolt cohorts, which are a key aspect of maintaining a wild population.Item The importance of marine-derived nutrients from anadromous fishes to Atlantic rivers(University of New Brunswick, 2017) Samways, Kurt M.; Cunjak, RichardWith the dramatic declines in Atlantic anadromous fishes over the past century it is important to identify the relative roles marine-derived nutrients (MDNs) delivered by these fishes play in influencing freshwater food web dynamics. Rivers in New Brunswick and Nova Scotia, Canada containing Atlantic salmon (Salmo salar), alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), or sea lamprey (Petromyzon marinus) as the primary anadromous species, were chosen to study their effects on i) primary production/productivity; ii) trophic interactions; and iii) resource quality. To understand the linkages between freshwater and marine ecosystems, observational studies, experimental frameworks, and analytical techniques (including stable isotope and fatty acid analysis) were employed. Biofilm communities followed a predictable response pattern to MDN inputs, regardless of the fishes spawning strategy, timing, or MDN load being delivered. Biofilm community standing crop and gross primary productivity were greater in sites receiving MDN subsidies than reference sites. The 13C and 15N data showed that MDNs were incorporated into all trophic levels (biofilm, invertebrates, and salmon parr) across streams with anadromous fish spawning. Community-wide niche space (i.e. the trophic diversity among food webs) shifted toward the marine-nutrient source, however the total ecological niche space (i.e. magnitude of trophic diversity) did not always increase with MDN inputs. Exposure to MDN resources from spawning Atlantic salmon led to improved nutritional quality for all biota, as indicated by increased lipid stores in all trophic levels and incorporation of fatty acids. The variability in fatty acid profiles was accredited to inherent differences between trophic groups combined with assimilation of marine-derived fatty acids in the MDN treatments. Precipitous declines in fish populations have resulted in a net loss in MDN loading to a point that may no longer sustain elevated levels of productivity needed for sustaining large fish populations. The current trend of declining anadromous fish populations in Atlantic Canada means fewer nutrient-rich marine subsidies for stimulating trophic production in these river systems. Marine-derived subsidies (nutrients and lipids) benefit multiple trophic levels of freshwater organisms as well as provide a cross-ecosystem spatial subsidy. In order to maintain ecosystem function and productivity, it is critical to include MDNs for effective ecosystem management and river restoration strategies.