2024 Onward

Permanent URI for this collectionhttps://hdl.handle.net/1807/137423

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Semi-pelagic self-adjusting otter boards: effects on the catching performance of a demersal trawl
(Canadian Science Publishing, 2024-01-01) Eighani, Morteza; Malta, Tiago Alexandre Matias da Veiga; Melli, Valentina; O'Neill, Finbarr G
In this study, we investigate whether replacing conventional seabed-contacting otter boards with semi-pelagic self-adjusting otter boards (SAO), which have the ability to maintain a given height above the seabed, affects catch efficiency of a demersal fish trawl. Experimental fishing trials, using the alternate haul method, were conducted in the Kattegat and Skagerrak with three otter board configurations using: conventional seabed-contacting otter boards; the SAO set to maintain a target height over the seabed of 1 m; and the SAO set to maintain a target height 5 m. Replacing conventional otter boards with SAO resulted in a loss of catch efficiency for haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), and plaice (Hippoglossoides platessoides), while no significant difference was found for cod (Gadus morhua), common dab (Limanda limanda) and lemon sole (Microstomus kitt). When comparing the SAO - 1m and SAO - 5m, it was observed that SAO - 5m resulted in a loss of catch efficiency for haddock and plaice, a minimal reduction for cod and no significant difference for whiting, common dab, and lemon sole.
Spatiotemporal dynamics of spawning habitat distribution of American shad (Alosa sapidissima) in the Hudson River Estuary under multi stressors
(Canadian Science Publishing, 2024-01-04) Chang, Hsiao-Yun; Pendleton, Richard; Kenney, Gregg; McKown, Kim; Eakin, William; Maniscalco, John; Chen, Yong
Diadromous fishes, known for their extensive migrations between freshwater and marine ecosystems, are highly vulnerable to environmental fluctuations and human activities, making them prone to population declines. Despite awareness of climate change impacts and habitat limitations, the remaining spawning habitat's biogeography is understudied. The present study focuses on the Hudson River Estuary (HRE) American shad (Alosa sapidissima) population which is experiencing historically low stock levels, as a case study to investigate the spatiotemporal distribution of its existing spawning habitat. Generalized Additive Models were used to investigate the effect of some environmental (e.g. temperature, river bottom type) and sampling variables (e.g. sampling location and time) on the spatial distribution of the American shad. Our results provide compelling evidence of an optimal spawning habitat for the American shad, suggesting that environmental factors may not be the primary drivers shaping the distribution of their spawning grounds. The significant relationships between the distribution of spawning habitat and spawning stock biomass indicates that factors beyond the HRE are likely to play the most significant roles in the shad population.
Estimating fish production in wetlands
(Canadian Science Publishing, 2024-01-23) Tucker, Caroline M; Giacomini , Henrique C.; Mandrak, Nicholas E.; Wang, Lifei; De Kerckhove, Derrick
Fish production integrates changes in biomass from growth, reproduction, and mortality, and is a useful indicator for fisheries management. However, calculation of fish production has been limited by the intensive requirements for data on abundance, biomass, age structure, and vital rates, and so it is uncommon to find estimates of fish production for wetlands. We developed an approach to directly estimate production that is suitable for data-limited systems: a continuous time model of production describing individual growth over short time intervals with continuous time models of abundance and biomass over longer timescales. We applied this model for 18 Great Lakes coastal wetlands (BLCW) on Lake Ontario, including Big Island Wetland (BIW). In BIW, most species were dominated in abundance and biomass by younger cohorts and, as a result, these young, fast-growing individuals contributed disproportionately to fish production. In total, BIW produced 336.1 kg/ha/year of fish and the other 17 neighbouring ranged between 447.7-1119.9 kg/ha/year. These are some of the first estimates of fish production for GLCW, highlighting their value for managing Great Lakes fisheries.
Ecological connectivity of invasive and native fishes in a historic navigation waterway
(Canadian Science Publishing, 2024-01-29) Bergman, Jordanna Nicole; Bennett, Joseph R.; Minelga, Valerie; Vis, Chantal; Fisk, Aaron T; Cooke, Steven J.
Regulated waterways, interconnected by navigation barriers (locks, dams), are uniquely difficult to manage given interest in enabling native species connectivity while minimizing invasions. Canada’s historic Rideau Canal Waterway, a 202-km navigable route located in eastern Ontario and connected by 23 lockstations, embodies this challenge. The lock(s) and water-control dam that compose each lockstation may respectively offer a connectivity pathway, though to what extent is unclear. We used acoustic telemetry (native largemouth bass [Micropterus nigricans], northern pike [Esox lucius]; invasive common carp [Cyprinus carpio]; n=224) to evaluate fish connectivity relative to lock operations and environmental data over three years (2019-2021). Thirty-five passages by 23 native fishes were recorded, with 49% of passages through locks. No common carp passages were detected; movements indicate they favour higher-flow areas downstream of dams, regions with no pathway upstream. Most passages were downstream and, of concern to obligate upstream migrators, we found that multi-flight and higher-lift locks appear impassable to upstream movements. Our results suggest these lockstations limit, but not entirely restrict, connectivity.
Epigenetic age estimation in a long-lived, deepwater scorpionfish: insights into epigenetic clock development
(Canadian Science Publishing, 2024-02-05) Weber, D. Nick; Fields, Andrew T.; Chamberlin, Derek W.; Patterson, William F.; Portnoy, David S.
Age estimates are essential for fisheries assessment and management, but deepwater (>200 m) fishes are often difficult to age using traditional techniques. Therefore, age-predictive epigenetic clocks were developed for a model deepwater reef fish, blackbelly rosefish Helicolenus dactylopterus, using two tissue types (fin clips and muscle; n = 61 individuals; 9−60 years) and Δ14C-validated consensus age estimates. The influence of biological information (length and sex) on epigenetic clock accuracy, and the potential for developing a multi-tissue clock, were also assessed. Bisulfite-converted restriction site-associated DNA sequencing (bsRADseq) was used to identify CpG sites (cytosines followed by guanines) exhibiting age-correlated DNA methylation, and epigenetic clocks showed strong agreement (R
Electronic tags reveal high migratory diversity within largest Atlantic halibut (Hippoglossus hippoglossus) stock
(Canadian Science Publishing, 2024-02-05) Ransier, Krista Tomaselli; Gatti, Paul; Le Bris, Arnault; den Heyer, Cornelia; Claireaux, Guy; Wringe, Brendan F.; Fisher, Jonathan AD
Growing evidence suggests that complex spatial structure occurs within the Scotian Shelf and southern Grand Banks (SSGB) Atlantic halibut stock, yet large knowledge gaps remain about migratory and spawning behaviors. Here, 71 pop-up satellite archival tags were deployed on large Atlantic halibut (FL: 87 - 166 cm) between 2012 and 2020. Migration tracks were successfully reconstructed for 43 fish using a hidden Markov geolocation model, and temperature and depth time series were available for nine fish (total n = 52). Five migratory behaviors were identified: shelf residency, slope residency, shelf-channel migration, shelf-slope migration, and dispersal. The high-resolution data for four of 20 physically recovered tags provided evidence for putative female spawning behavior in deep channels on the continental shelf and along the continental slope between January and February. Additionally, four halibut displayed previously undocumented periods of sustained, oscillatory vertical movement along the continental slope between November and February. The high migratory diversity observed in the SSGB stock supports the existence of multiple resident and migratory contingents in the stock in the apparent absence of significant genetic structure.
Revisiting the influence of top-down and bottom-up pressures on Wa hia hé:ta (yellow perch Perca flavescens Mitchill, 1814) population dynamics in Kaniatarowanenneh (the Upper St. Lawrence River): Implications for collaborative research
(Canadian Science Publishing, 2024-02-20) Perron, Mary Ann C; Charette, Cristina; Francis, Abraham T.; Holden, Courtney; Moyle, Madeleine; Boyle, John; Franceschini, Jaclyn; Hickey, Brian MBC; Nurse, Amanda; Ridal, Jeffrey J.; Shuji, Kaz; Windle, Matthew J.S.; Wylie-Arbic, Mackenzie; McGaughey, Leigh J.
Kaniatarowanenneh (St. Lawrence River) is the outflow of one of the world’s largest freshwater ecosystems and its ecological health has implications for resource management. The population dynamics of an ecologically and economically important fish, the Wa hia hé:ta, Mohawk for yellow perch (Perca flavescens Mitchill, 1814), are considered by including data that extends to the past century to redress temporal gaps in comparative literature. We found both a significant top-down effect from piscivorous fish as well as a significant bottom-up effect related to total phosphorus on yellow perch relative abundance in the Lake Ontario-Upper St. Lawrence system. Regarding the bottom-up effect, the current state of yellow perch reflects the population size prior to cultural eutrophication (pre-1940s/50s) likely responding to the re-oligotrophication of the system. These findings emphasize the importance of considering historical records in fish population dynamics research to incorporate shifting population baselines into fisheries management. The study also demonstrates the need for collaborative approaches that bring critical new insights and multivocality.
Northern cod re-establish historical migration patterns linked to capelin: insights from pop-up satellite archival tags
(Canadian Science Publishing, 2024-02-29) Rose, George A; Rowe, Sherrylynn
In May of 2012 to 2015, 90 large (85-117 cm) Northern cod (Gadus morhua) with pop-up satellite archival tags (PSATs) set to release one year later were released from offshore spawning aggregations on the northeast Newfoundland shelf. Forty-nine (54%) transmitted or were recovered; 82% migrated inshore, 15% remained offshore (balance predated). Geo-locations were based on release, capture, and surfacing positions, and at tag-recorded depths
Effects of temperature, body size, and sex on the standard metabolic rates of a sexually dimorphic freshwater piscivore, walleye (Sander vitreus)
(Canadian Science Publishing, 2024-03-04) Bihun, Christian Joseph; Murphy, Megan K.; Johnson, Timothy B.; Fisk, Aaron T; Guzzo, Matthew M; Madenjian, Charles P; Raby, Graham
Walleye (Sander vitreus) are a sexually dimorphic freshwater piscivore that have long been studied using bioenergetics modeling, yet robust estimates of metabolic rates for use in those models have been lacking. Therefore, we quantified the effects of body mass, water temperature, and sex, on standard metabolic rate (SMR). We estimated SMR across temperatures ranging 0.5-24 °C using intermittent-flow respirometry for male (n = 54) and female (n = 53) walleye raised in hatchery conditions. We found a significant interaction between sex and temperature, whereby males had lower SMR below 16 °C, but increased such that SMR was ~16% higher than females at 22 °C. The mass-scaling coefficient, b, was similar for both sexes at a value around 1. These estimates of metabolic rate are the first to be generated using respirometry for adult walleye and differ slightly from those being used by previous bioenergetics models, which may have underestimated the energetic costs of SMR, and did not include sex-specific estimates for metabolism.
Effects of temperature, body size, and sex on the standard metabolic rates of a sexually dimorphic freshwater piscivore, walleye (Sander vitreus)
(Canadian Science Publishing, 2024-03-04) Bihun, Christian Joseph; Murphy, Megan K.; Johnson, Timothy B.; Fisk, Aaron T; Guzzo, Matthew M; Madenjian, Charles P; Raby, Graham
Walleye (Sander vitreus) are a sexually dimorphic freshwater piscivore that have long been studied using bioenergetics modeling, yet robust estimates of metabolic rates for use in those models have been lacking. Therefore, we quantified the effects of body mass, water temperature, and sex, on standard metabolic rate (SMR). We estimated SMR across temperatures ranging 0.5-24 °C using intermittent-flow respirometry for male (n = 54) and female (n = 53) walleye raised in hatchery conditions. We found a significant interaction between sex and temperature, whereby males had lower SMR below 16 °C, but increased such that SMR was ~16% higher than females at 22 °C. The mass-scaling coefficient, b, was similar for both sexes at a value around 1. These estimates of metabolic rate are the first to be generated using respirometry for adult walleye and differ slightly from those being used by previous bioenergetics models, which may have underestimated the energetic costs of SMR, and did not include sex-specific estimates for metabolism.
Multiple signs of ecosystem change in the zooplankton community of a large temperate lake
(Canadian Science Publishing, 2024-03-06) Young, Joelle D; Jarjanazi, Hamdi; Palmer, Michelle
Large lakes, such as Lake Simcoe, Ontario, Canada, are undergoing significant change due to local and global stressors. Uni- and multivariate analyses of Lake Simcoe’s zooplankton community from 1986 to 2012 indicated multiple events of ecosystem change that were synchronous across three lake stations. In the mid-1990s, shifts in zooplankton species abundance and richness, and total cladoceran body size were strongly correlated with the invasion of the zooplanktivore, Bythotrephes cederstroemii. In the early 2000s, additional shifts in zooplankton abundance, as well as copepod body size, coincided with increased water clarity (linked to filter feeding by the invader Dreissena polymorpha) and hypolimnetic water temperature. Further community changes occurred in the 2000s when Bythotrephes declined and many vulnerable cladoceran species recovered. However, the Lake Simcoe community did not fully return to its pre-invasion state as the cold-water herbivores, Daphnia longiremis and Daphnia pulicaria, remained absent. The Lake Simcoe zooplankton community illustrates ongoing ecosystem change that propagated throughout the lake food web, and may be reflected in other lakes experiencing global stressors of climate change and species invasions.
A systemic approach to analyzing post-collapse adaptations in the Bay of Biscay anchovy fishery
(Canadian Science Publishing, 2024-03-11) Beckensteiner, Jennifer; Villasante, Sebastian; Charles, Anthony; Petitgas, Pierre; Le Grand, Christelle; Thebaud, Olivier
The Bay of Biscay anchovy fishery system has undergone important transformations following a closure from 2005 to 2010. Through a multidisciplinary and systemic approach, combining analyses of fisheries and market data with interviews with key stakeholders, we analyze adaptive responses of the main system components in France and Spain, considering how the fishing sector and fishery management institutions have adapted to changes. Focusing on the question “what has been lost and gained following the collapse?”, we find that while the anchovy stock has recovered, the fishery system has not returned to its pre-collapse status with important socio-economic features having been lost. We highlight the need for holistic consideration of multiple system components and diverse stakeholders’ perspectives. The perceived losses and gains from the anchovy fishery collapse and aftermath are found to vary across the players in the fishery system, depending as well on the management objectives and scales being considered. Such retrospective analysis can serve as a basis for understanding the long-term responses to social-ecological changes in fisheries, and identifying the role of governance mechanisms in supporting adaptations that maintain sustainable fishery systems in the face of future potential shocks.
Estimating whisker growth rates and foraging profiles for northern fur seal pups and adult females using stable isotope analysis
(Canadian Science Publishing, 2024-03-30) Howard, Tanner; Orr, Anthony AJ; Narel, Kimberly; Kurle, Carolyn
Changing ratios of stable carbon (δ
Stable isotope analysis provides novel insights for measuring lake ecosystem recovery following acidification
(Canadian Science Publishing, 2024-04-02) Dawson, Jade; Guzzo, Matthew M; Gunn, John M; Emilson, Erik J.S.; McCann, Kevin S.; Edwards, Brie
Unstable and simplified freshwater food webs impair the resilience of Canadian fisheries facing environmental stressors. This study utilizes stable isotope analyses to assess trophic recovery to explore food web resiliency in lakes historically impacted by metal mining in Sudbury, Ontario. Carbon (δ 13C) and nitrogen (δ 15N) stable isotope ratios were quantified in yellow perch (Perca flavescens), smallmouth bass (Micropterus dolomieu), and baseline organisms to develop quantitative population metrics and describe dietary niche partitioning. The most severely damaged lake with a barren watershed had the lowest trophic positioning, smallest body size and niche area, and greatest niche overlap among fish species. Semi-barren and forested watershed lakes were more similar to reference lakes in isotopic metrics; however elevated niche overlap and reduced trophic positioning suggests recovery in these lakes is ongoing. We found that including stable isotope analyses in lake recovery studies provided critical insights not captured by traditional biomonitoring approaches.
Estimating spawning Green Sturgeon (Acipenser medirostris Ayres, 1854) abundance in the Sacramento River using side-scan sonar and N-mixture models
(Canadian Science Publishing, 2024-04-07) Battaile, Brian Charles; Mora, Ethan A.; Lehman, Brendan; Dudley, Peter N
Current estimates of the threatened southern distinct population segment of the North American Green Sturgeon (Acipenser medirostris) combine a plot-sampling density estimator with DIDSON and ARIS sonar data. From 2020 to 2022, we annually collected images of all known Green Sturgeon aggregations and compared the established method to an N-mixture model using side-scan sonar images. We compared 18 different N-mixture model combinations and chose an overdispersed Poisson model that produced estimated abundances of 742, 1286 and 1208 for 2020-2022 respectively. These numbers are ~2 times greater than the previous method and if sustained, would fulfill a key criterion for Green Sturgeon recovery. N-mixture models are known to be sensitive to violations of assumptions, such as the highly dispersed data from our study that caused serious issues, and we recommend practitioners make judicious use of overdispersion and goodness of fit tests and to be able to identify parameter confounding between detectability and abundance estimates. For our Green Sturgeon, we recommend simpler population estimates, and to focus future energy on reducing variability in the data collection process.
A probabilistic foundation for the study of larval fish feeding, growth, and mortality rates
(Canadian Science Publishing, 2024-04-25) Pepin, Pierre
Survival through the larval phase is predicated on the probabilities of successful feeding, which dictates growth rates, and the probabilities of encountering predators. Here I perform a synthesis of feeding, growth, and mortality rates estimated during several studies from coastal Newfoundland, Canada, to provide a description of the probability distribution that can serve as a foundation of the expected distribution of vital rates. The standardized observations clearly follow that of skewed distributions, appropriately fit to a probability gamma distribution, with feeding demonstrating a stronger degree of skewness than either mortality or growth, possibly because each vital rate integrates prey-predator interactions over different time scales. Commonality in the underlying form of the distribution of vital rates in larval fish, along with clear functional relationships between gamma parameters, represents a probabilistic basis of expectations against which observations from prior or new studies can be contrasted. An example of the use of such expectations demonstrates that they can provide useful contextual information about the contrast among observations and our ability to identify their relationship with environmental drivers.
Declines and shifts in morphological diversity of ciscoes (Coregonus spp.) in lakes Huron and Michigan, 1917-2019
(Canadian Science Publishing, 2024-04-25) Fedorowicz, Paul; Kao, Yu-Chun; Ackiss, Amanda; Anweiler, Katie; Honsey, Andrew E.
Ciscoes (Coregonus spp.) were historically abundant and ecologically important in Laurentian Great Lakes ecosystems. Despite well-documented declines in their abundance and taxonomic diversity, declines in morphological diversity remain understudied. This knowledge gap is especially pertinent for lakes Michigan and Huron, which have each lost six of eight historical species. Improved understanding of historical and contemporary morphological diversity of Great Lakes ciscoes can inform ongoing restoration efforts and further elucidate the factors that contributed to declines. Our goal was to characterize shifts in morphological diversity of ciscoes in lakes Michigan and Huron over a century (1917-2019). We analyzed size-corrected morphometric and meristic measurements from three periods: Early (1917-1923), Middle (1950-1972), and Contemporary (2015-2019). We then identified morphologically distinct clusters while remaining agnostic to species identifications. We found that morphological diversity and the number of distinct clusters declined over time. We then leveraged species identifications to highlight key species losses and examine morphological shifts among extant species. Our findings provide insights into the historical and contemporary morphological diversity of ciscoes and will inform restoration efforts.
Developing management plans for sprat (Sprattus sprattus) in the Celtic Sea consistent with an Ecosystem Approach to Fisheries
(Canadian Science Publishing, 2024-04-25) Kell, Laurence T.; Bentley, Jacob; Feary, David; Egan, Afra; Nolan, Cormac
Sprat are commercially valuable and are an important component of the North-East Atlantic ecosystem as major predators of zooplankton, competitors with herring, and prey for piscivorous fish, marine mammals, and seabirds. Despite this, insufficient information exists for Celtic Seas sprat, one of five North-East Atlantic stocks, to estimate stock status. To ensure the sustainable exploitation of sprat, the health of the Celtic Seas ecosystem and the wider fisheries sector, we conduct a Management Strategy Evaluation to stress test the current single-species advice framework. The aim is to evaluate whether ecosystem objectives can be achieved under single-species maximum sustainable yield and precautionary advice frameworks. An Operating Model was conditioned on life-history theory and strategic information from ecosystem models. We showed that in-year advice using an empirical rule could achieve management objectives and help balance the trade-offs between fishing activities and ecosystem health. The approach allows ecosystem understanding to be incorporated within existing precautionary and maximum sustainable yield frameworks to provide a robust management framework that can meet multiple objectives despite uncertainty.
Variation in estuary use patterns of juvenile Chinook salmon in the Fraser River, BC
(Canadian Science Publishing, 2024-05-03) Scott, David Christopher; Chalifour, Lia; MacDuffee, Misty; Baum, Julia K.; Beacham, Terry; Rondeau, Eric B.; Hinch, Scott G
Juvenile Pacific salmon (Oncorhynchus spp.) use estuary habitats to varying degrees with some species and populations thought to rely heavily on these areas for early growth. In the Fraser River, British Columbia, there are 18 distinct Conservation Units of Chinook salmon (O. tshawytscha), and all but one is of conservation concern. Our study compares the outmigration timing, size, and habitat use of juvenile Chinook salmon in the Fraser River estuary. Over five years (2016-2020) we captured 6,493 juvenile Chinook salmon, with 3,318 sampled for stock identification. Fraser River Chinook salmon extensively used estuary habitats, but patterns varied considerably by population. Juvenile Chinook salmon from the Lower Fraser River were most abundant and present the longest, arriving the smallest in late March and early April, and captured until July. South Thompson ocean-type Chinook salmon entered the estuary later, starting to arrive in late May or early June and remaining present until mid-August. Overall, juvenile Chinook salmon varied considerably in their estuary use across populations. Understanding this variation can inform differences in productivity and guide recovery actions.
Enhancing data-limited assessments with random effects: A case study on Korea chub mackerel (Scomber japonicus)
(Canadian Science Publishing, 2024-05-29) Kim, Kyuhan; Sibanda, Nokuthaba; Arnold, Richard; A'mar, Teresa
In a state-space framework, temporal variations in fishery-dependent processes can be modeled as random effects. This modeling flexibility makes state-space models (SSMs) powerful tools for data-limited assessments. Though SSMs enable the model-based inference of the unobserved processes, their flexibility can lead to overfitting and non-identifiability issues. To address these challenges, we developed a suite of state-space length-based age-structured models and applied them to the Korean chub mackerel (Scomber japonicus) stock. Our research demonstrated that incorporating temporal variations in fishery-dependent processes can rectify model mis-specification but may compromise robustness, which can be diagnosed through a series of model checking processes. To tackle non-identifiability, we used a non-degenerate estimator, implementing a gamma distribution as a penalty for the standard deviation parameters of observation errors. This penalty function enabled the simultaneous estimation of both process and observation error variances with minimal bias, a notably challenging task in SSMs. These results highlight the importance of model checking and the effectiveness of the penalized approach in estimating SSMs. Additionally, we discussed novel assessment outcomes for the mackerel stock.

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