Ecology of Freshwater Fish最新文献

Curtis, K., Sanders, A., Urbanic, M., Israel, G., McCombs, C., Pastura, L., Matter, S. F., & Booth, M. T. (2024). The influence of flow on movement of a headwater specialist in an intermittent urban headwater stream. Ecology of Freshwater Fish, 33, e12744. https://doi.org/10.1111/eff.12744

In the originally published article, co-author Connor McCombs was inadvertently left off the author list. The correct author list is as follows:

Katherine Curtis, Adam Sanders, Megan Urbanic, Gabriyelle Israel, Connor McCombs, Logan Pastura, Stephen F. Matter and Michael T. Booth

Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA

This has been corrected in the online version of the article.

We apologise for this error.

In May of 2023, about 100 scientists met for the sixth time over ~25 years for the ‘Advances in the Population Dynamics of Stream Salmonids’ Symposium. This symposium, created by the father of brown trout ecology, Dr. Javier Lobón-Cerviá and colleagues, grew out of intriguing conversations regarding the regulation of the population dynamics of salmonids, as long ago as the 1980s. The first symposium was in the quaint coastal town of Luarca, Spain, in 1998 and started out small with less than ~50 scientists in attendance. The second symposium, also more modest in numbers (~85 scientists), was held in 2006 in millenary Leon in the NW of Spain, a town proud of its history and its Cathedral of nearly 2000 square metres of stained glass and in-credible (free!) tapas. The third was in 2010 back in the stunning fishing town of Luarca, where our numbers grew substantially to more than 115, we moved into a fancy new conference hall, and we feasted on fresh seafood. The fourth was in 2015 and held in Girona (101 scientists), in the NE of Spain, where we all felt ethereal while giving our talks in a stunning cathedral-like hall and where we experienced the strong Catalonian culture and cuisine. This was followed by a meeting in Granada, Spain, in 2019, where we strolled the halls and gardens of the magnificent Alhambra after riveting days of science talks.

Finally, in May of 2023, we met in lovely and lively Majorca, one of Spain's Balearic Islands in the Mediterranean, and convened at the University of Balearic Islands. We ate delicious foods, as Majorca has many cultural influences, and toured a magnificent cave, where we were serenaded by live classical music. We met with old friends and new friends and shared new experiences, and our numbers of participants grew yet again. Topics covered included the roles of tributaries, influences on growth rates, recruitment, dispersal and migration, genetics, spawning, habitat, innovative conservation, restoration and management, habitat, and even beer and salmon, to name just a few. At each iteration, we have received new fresh faces and perspectives, but our alumni base has held strong, offering continuity in the advancement of the study of the population dynamics of stream salmonids.

Selected proceedings from the May 2023 Majorca symposium follow. The articles cover a wide range of topics, from eco-evolutionary dynamics to how to measure biologically relevant temperature in fish, for example. In this way, these proceedings show the importance of understanding and studying stream living salmonids at a wide range of scales.

P.B. and L.A.V. both equally conceived of and wrote this short introduction.

The authors declare no conflicts of interest.

Dispersal is a ubiquitous ecological process that has been extensively studied in many plants and animals. Anadromous salmonids are an interesting system for examining dispersal, in part because of their well-known philopatric behaviour, but also because of the conservation challenges related to the dispersal of hatchery-origin fish. Building on earlier work, we provide an updated systematic review of dispersal and gene flow in anadromous salmonids. In particular, we compared studies on the dispersal of anadromous salmonids from wild and hatchery origins, including studies providing estimates of dispersal rates, observations of dispersal and results from modelling studies. We reviewed 228 studies and found these were unevenly distributed among species, with Atlantic salmon, Chinook salmon and sea trout being well-represented. Our results showcase considerable variability in estimated dispersal rates within and across studies, which is likely related to the different methodologies, dispersal propensities across species and populations, and spatial extents considered. Overall, our results confirmed a higher tendency of hatchery fish to disperse relative to wild fish, but we also found some variation across species that warrants further study. Moreover, we found that dispersal propensity tended to decline exponentially with distance and that the drivers of dispersal varied considerably among studies. Additionally, we highlight various facets of dispersal captured across this suite of studies, including variation in terminology, methods and metrics for characterising dispersal, and the spatio-temporal scales considered. Finally, our review revealed that few studies considered, and even fewer assessed, the implications of dispersal for the conservation and management of anadromous salmonids.

The management of intraspecific diversity in many species is usually disconnected from eco-evolutionary processes happening in natura. A classic example is embodied in the problem of introgression in hybridized fish populations, wherein management practices are generally unaware of any selective process at work, and therefore generally rely on numbers (adding or removing individuals) to reduce introgression. Such an example can be observed in the French Alps, where native Mediterranea (MED) brown trout have been highly introgressed through decades of stocking with domesticated Atlantic (ATL) brown trout. Recently however, new results shed light on a potential selective mechanism that may affect differentially the fitness of MED and ATL genes depending on the environment (GxE interaction). Using a demogenetic agent-based model able to account for such GxE interaction, we simulate a management scenario implemented in 2005 by some biodiversity managers and scientists, who attempted to restore the Mediterranea gene pool using translocation of near pure MED individuals in Atlantic-dominated areas. We show that the model is unable to recreate the observed introgression dynamics if the GxE interaction is not included. This finding implies that (i) eco-evolutionary mechanisms can have large effects on introgression dynamics on very short time scales and (ii) management of intraspecific diversity should increasingly rely on these natural mechanisms, so as to improve management targets and facilitate adaptation to rapid environmental changes.

Large dams significantly impact river ecosystems by disrupting connectivity, altering physicochemical variables, and modifying flow regimes. These modifications influence the spatial and temporal dynamics of biological processes and species distributions. While much research has focused on potamodromous species, there remains a gap in understanding the recovery gradients of resident species in dam-altered rivers. This study examines the responses of larvae of a resident species, the mandarin fish (Siniperca chuatsi), to environmental alterations caused by the Three Gorges Dam (TGD) in the middle reach of the Yangtze River. We hypothesized that larval abundance, feeding, growth, and survival would exhibit longitudinal recovery gradients, improving with the increased distance from the TGD. Our results confirm this hypothesis, showing that larvae further from the TGD exhibited higher abundance, increased feeding intensity, enhanced growth rates, improved survival rate, and earlier peak abundance and hatching dates. Key environmental factors, including water temperature and discharge, increased downstream, while transparency decreased. Major tributary inputs significantly contributed to these recovery gradients. The observed longitudinal gradients in larval attributes mirrored environmental changes, underscoring the TGD impact on population recruitment. These results highlight the broader implications of dam-induced changes on resident species recruitment, potentially affecting entire fish communities. Our study contributes to understanding the distinct spatial patterns of population trends, providing valuable insights for designing more effective conservation and management practices for resident freshwater fishes in large regulated rivers.

Hybridisation is a complex process that begins with mating. Females have more to lose with each hybrid fertilisation than males, so they should avoid it. Even if females choose con-specific males as preferred mates, they often cannot control which additional males release sperm during spawning. Polyandry is ubiquitous and may result in hetero-specific sperm competition between males of different species. In such cases, cryptic female choice (the ability to bias paternity towards certain males under sperm competition) is the last line of defence to prevent hybridisation of her eggs and is highly adaptive if it enables con-specific sperm preference. Such seems to be the case with the hybridisation of Atlantic salmon (Salmo salar) and brown trout (S. trutta) in their native Europe. Under hetero-specific sperm competition, hybrid fertilisations in these fish are reported to be reduced via ovarian fluid-mediated cryptic female choice. It is not known, however, whether the strength of this mechanism is dependent on reinforcement and thus, the historical sympatry/allopatry of hybridising populations. Brown trout are one of the world's worst invasive species. Ecological impacts arise through competition with other species (e.g. Galaxids in the southern hemisphere, Oncorhynchus in western North America). Eastern North America contains native salmonids that evolved in the absence of brown trout but have gametes that are compatible. The 140 -year-old brown trout invasion of Newfoundland is ground zero to study these potential interactions. Their relatively low spread rate across the island may be the result of inherent poor productivity, but data suggest it could also be a function of hybridisation with native Atlantic salmon and brook char (Salvelinus fontinalis).

Tracking of animal migrations using telemetry technologies needs to take into consideration the burden that the tag exerts on the animal. Here, we examined the potential impacts of acoustic tags of two sizes (nominally a ‘V6’ [smaller] and ‘V7’ [larger]) on the downstream riverine migration success and behaviour of wild Atlantic salmon (Salmo salar L.) smolts. One hundred fish were tagged with either a V6 or V7 tag. Tag burden (tag: fish weight) ranged from 1.88% to 7.39% and differed significantly between fish tagged with the V6 (mean [SD] = 3.63% [0.51%]) and the V7 tags (mean [SD] = 5.84% [0.95%]). There was no significant difference in the in-river migration failure between the two groups when tested with a time-to-event analysis. There were also no differences in other elements of the migratory behaviour (rate of movement, time of detection and residency time) between the two tagging groups. These data support the use of acoustic tracking for monitoring smolt migration and highlight that tagging of smaller smolts at up to 7.39% tag burden to gain a more representative understanding of migration success and behaviours across a smolt population.

Migratory fish species have been particularly impacted by changes to the hydrologic and climatic cues to which migration and spawning behaviours have been adapted across generations. While conservation and recovery programs increasingly implement flow management actions to promote successful migration and spawning, uncertainty regarding how spawning migration phenology responds to changing environmental conditions can limit the ability to effectively target such recovery actions. Here, we use a Bayesian hierarchical modelling framework to analyse spawning migration phenology of individually tagged June suckers (Chasmistes liorus) – a federally threatened, long-lived, iteroparous, adfluvial species endemic to Utah Lake (Utah, USA) and its tributaries. We then examine how annual hydrologic and thermal conditions relate to different components of annual migration phenology, including peak migration date, in-stream residence time, and among-individual variation in migration timing. Peak migration date occurred earlier in years with warmer spring air temperatures (a proxy for water temperatures), though this effect interacted with peak runoff timing. Both residence time and among-individual variation in migration timing were greater in years with larger spring discharge and later peak flows. Residence time was also longer in warmer years. These results highlight how natural and anthropogenic changes to river flow and thermal regimes are likely to impact June sucker migration timing and duration, and our approach can be applied to other migratory species to identify the external drivers of the different components of migration phenology.

The recent miniaturisation of implantable temperature recording tags has made measuring the water temperatures fish experience in the wild possible, but there may be a body size-dependent delay in implanted tag response time to changes in external temperature. To determine whether fish body size affects the response rate of implanted temperature tags, we implanted 20 Salvelinus fontinalis (127–228 mm fork length (FL), 15.1–120.4 g) with temperature recording tags and subjected them to rapid temperature changes (±8°C in less than 2 seconds) in the laboratory. We found that thermal transfer rates, and the lag in temperature tag response rate, was positively correlated with fish size, but the direction of temperature change (colder or warmer) had no significant effect. In fish exposed to a slower rate of temperature change (2°C h⁻¹) implanted tags did not show a response lag. Understanding the limitations of this important technology is crucial to determining the utility of the data it produces and its ability to accurately measure fish thermal experience in the wild.