Energetic Trade‐Offs Faced by Brown Trout During Ontogeny and Reproduction

Berg, Ole Kristian; Fleming, Ian A.

doi:10.1002/9781119268352.ch8

Cited by 2 publications

(2 citation statements)

References 80 publications

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“…Moreover, a decreased reproductive output will not only have implications for the persistence of the local population but may also negatively affect the neighbouring population by a reduced supply of recruits. Apart from having a direct influence on the number of offspring a female may produce, empirical evidence exists that the amount of energy a female has available to invest into egg production will also affect egg quality, and this in turn the offspring's fitness (Bagenal, 1969;Crespi and Semeniuk, 2004;Berg and Fleming, 2017).…”

Section: Population Dynamicsmentioning

confidence: 99%

How artificial potential field algorithms can help to simulate trade-offs in movement behaviour of reef fishes

et al. 2022

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IntroductionSpace use patterns in fish result from the interactions between individual movement behaviour and characteristics of the environment. Herbivorous parrotfishes, for instance, are constrained by the availability of resources and different predation risks. The resulting spatial distribution of the fish population can strongly influence community composition and ecosystem resilience.MethodsIn a novel approach, we combine individual-based modelling (IBM) with an artificial potential field algorithm to realistically represent fish movements and the decision-making process. Potential field algorithms, which are popular methods in mobile robot path planning, efficiently generate the best paths for an entity to navigate through vector fields of repellent and attracting forces. In our model the repellent and attracting forces are predation risk and food availability, both implemented as separate grid-based vector fields. The coupling of individual fish bioenergetics with a navigation capacity provides a mechanistic basis to analyse how the habitat structure influences population dynamics and space utilization.ResultsModel results indicate that movement patterns and the resulting spatial distributions strongly depend on habitat fragmentation with the bioenergetic capacity to spawn and reproduce being particularly susceptible processes at the individual level. The resulting spatial distributions of the population are more irregularly distributed among coral reef patches the more the coral reef habitat becomes fragmented and reduced.DiscussionThis heterogeneity can have strong implications for the delivered ecosystem functioning, e.g., by concentrating or diluting the grazing effort. Our results also highlight the importance of incorporating individual foraging-path patterns and the spatial exploitation of microhabitats into marine spatial planning by considering the effects of fragmentation. The integration of potential fields into IBMs represents a promising strategy to advance our understanding of complex decision-making in animals by implementing a more realistic and dynamic decision-making process, in which each fish weighs different rewards and risks of the environment. This information may help to identify core areas and essential habitat patches and assist in effective marine spatial management.

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Section: Population Dynamicsmentioning

confidence: 99%

How artificial potential field algorithms can help to simulate trade-offs in movement behaviour of reef fishes

et al. 2022

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“…Notably absent from this list is population reproductive structure—the proportion of the population in different reproductive stages or phases. Reproductive structure is expected to vary with somatic growth rates and energetic status, as determined by environmental conditions and competition (Berg and Fleming 2017; Manabe et al 2018), and is expected to have a strong influence on the reproductive potential of a population. The present study was motivated by the need for more rigorous assessments of reproductive structure in wild fish populations to better understand the linkage between somatic growth, energetic status, reproductive dynamics, and recruitment.…”

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confidence: 99%

Population Reproductive Structure of Rainbow Trout Determined by Histology and Advancing Methods to Assign Sex and Assess Spawning Capability

Crossman

Webb

Korman³

et al. 2022

Trans Am Fish Soc

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Rainbow Trout Oncorhynchus mykiss have been intensively studied and gametogenesis has been described, but the use of reproductive indices in field studies has not been widely applied when assessing variability in growth or recruitment dynamics. We integrated descriptions for gametogenesis within the framework of standardized terminology for reproductive development in teleosts to develop sex‐specific criteria for assignment of reproductive phases. We used these descriptions and histological analysis of gonad tissue collected from Rainbow Trout in the Colorado River downstream from Glen Canyon Dam to quantify season‐, size‐, and sex‐specific variation in population reproductive structure. The accuracy of nonlethal methods (manual expression and ultrasonography) was evaluated for assigning sex by comparing estimates with those determined by histology. Rainbow Trout were sampled through an annual spawning cycle from October 2018 to April 2019. Spawning capable males were available across the entire period, with a higher proportion earlier in the season compared to later. Females were spawning capable in October, with a peak in February; by April, they were in the early developing phase, indicating that spawning had ended. Elevated levels of atresia (19% for fall spawners) and evidence for delayed maturation were identified, suggesting energetic limitations on the reproductive potential of the population. For both sexes, the probability of being spawning capable increased with fork length, with minimum sizes of ≥283 mm for females and ≥187 mm for males. Sex assignment using ultrasonography was more accurate (46%) than manual expression of gametes (9%), as only a small proportion of males and females expressed gametes. Probabilities of correct sex assignment using ultrasonography were strongly influenced by reproductive phase, with spawning capable fish (females: 100%; males: 77%) having significantly higher probabilities of correct sex assignment compared to immature fish. Furthermore, probabilities of correct sex assignment increased with fish size and were higher for females than for males. Results provide a framework for quantifying spawning capability and population reproductive structure in ongoing research to better understand the drivers of recruitment variability in aquatic ecosystems.

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Energetic Trade‐Offs Faced by Brown Trout During Ontogeny and Reproduction

Cited by 2 publications

References 80 publications

How artificial potential field algorithms can help to simulate trade-offs in movement behaviour of reef fishes

How artificial potential field algorithms can help to simulate trade-offs in movement behaviour of reef fishes

Population Reproductive Structure of Rainbow Trout Determined by Histology and Advancing Methods to Assign Sex and Assess Spawning Capability

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