Bio-physical Interactions of Small Pelagic Fish Schools and Zooplankton Prey in the California Current System Over Multiple Scales

Bio-physical Interactions of Small Pelagic Fish Schools and Zooplankton Prey in the California Current System Over Multiple Scales
Author: Amanda May Kaltenberg
Publisher:
Total Pages: 262
Release: 2010
Genre: Marine ecology
ISBN:

Small pelagic fish represent a critical trophic link between plankton and large predators in marine upwelling ecosystems such as the California Current System. Populations of these fish are highly variable over time and are characterized by extreme fluctuations in abundance, which have significant ecosystem impacts. The causes driving this instability are not well understood, but several climactic and ecological factors have been hypothesized. This research investigated the linkages between habitat, plankton prey resources, and the abundance and behavior of small pelagic fish at various temporal and spatial scales (i.e., daily, weekly patterns of wind-driven upwelling, and seasonal) to understand how changes in physical and prey habitats influence trophic interactions. This research utilized a combination of stationary and shipboard acoustics, net sampling, and physical oceanography sampling approaches. A comparison of diel schooling behavior and zooplankton availability off Oregon and Monterey Bay, California revealed that changes in fish aggregation behaviors were caused by different timings of zooplankton availability in each region attributable to the extent of zooplankton diel vertical migrations. An analysis of the spatial relationships of acoustic scatterers across ocean fronts caused by wind-driven coastal upwelling indicated that upwelling may lead to a spatial mismatch between small plankton prey and schooling fish that select habitat based on their preference of warmer temperatures. The temporal patterns of zooplankton and pelagic fish abundance near the Columbia River plume were identified, finding that the seasonal appearance of small pelagic fish occurred very abruptly. The timing of fish arrival was poorly correlated with zooplankton abundance but was strongly linked with temperature, salinity, and river flow. Zooplankton abundance was highly variable with very large spikes occurring with the passage of tidally-driven river fronts. This research on the ecological and environmental factors between habitat, plankton, and small pelagic fish has revealed that both the physical habitat and prey fields play an important role in determining these interactions. Variability in the trophic interaction between small pelagic fish and zooplankton over varying scales has important ecosystem consequences, including the potential availability of these prey resources to larger predators, as well as impacts for management.

Collected Reprints

Collected Reprints
Author: Southwest Fisheries Center (U.S.)
Publisher:
Total Pages: 684
Release: 1986
Genre: Fisheries
ISBN:

Fine-scale Distributions of Plankton and Larval Fishes

Fine-scale Distributions of Plankton and Larval Fishes
Author: Adam T Greer
Publisher:
Total Pages:
Release: 2013
Genre:
ISBN:

Describing the distributions of organisms on scales relevant to individuals (1-100 m) is critical to understanding predator-prey interactions within the plankton. This has driven the development of plankton imaging technology with synoptic physical parameters (temperature, salinity, depth), which facilitates high-resolution taxonomic and spatial descriptions. We utilized a novel In Situ Ichthyoplankton Imaging System (ISIIS) that addressed some shortcomings of other imaging systems by allowing for the simultaneous sampling of both abundant (e.g., copepods, appendicularians, marine snow) and rare (e.g., fish larvae, medusae, ctenophores) members of the plankton community. The main objectives of this study were 1) to describe the physical and biological characteristics of the fine-scale environments near ubiquitous coastal features (fronts, thin layers, and internal waves), and 2) how these descriptions related to trophic interactions potentially affecting the early life stages of fishes. ISIIS was deployed in three separate environments with characteristic hydrographic regimes favorable to the formation of thin layers, internal waves, and fronts. In northern Monterey Bay, thermal stratification led to the development of thin layers of diatom aggregates dominated by Pseudo-nitzschia spp. A variety of gelatinous taxa tended to aggregate within or below thin layers, while copepods seemed to avoid the thin layers and were often found near the surface. The vertical separation of predators and prey showed support for predation avoidance by copepods, with thin layers creating a strong gradient in light levels facilitating contact predation by gelatinous zooplankton at depth. The physical environment near Stellwagen Bank was dominated by a tidally driven oscillation between high stratification and internal wave activity. Copepods were found near the surface, sometimes aggregating in a thin layer several meters shallower than the chlorophyll-a maximum. Larval fishes were found to strongly correlate with the copepods, suggesting they feed on concentrations of prey much higher than average. After the passage of internal waves, larval fish correlation with prey was reduced, while predators, which were abundant at depth, had higher correlation with larval fishes. Internal waves reduced patchiness for a variety of taxa, potentially creating less favorable planktonic habitat for larval fishes. At the shelf-slope front near Georges Bank, we investigated the impact of horizontal gradients on the distribution of plankton. Almost all plankton taxa were found in high abundance on the shelf side of the front. A particle solidity metric showed distinct habitat partitioning of different plankton taxa around the front, with copepods and appendicularians forming a near surface layer just above the convergence of isopycnals defining the front. These grazers were spatially separate from diatom aggregates, which were abundant in zones of high chlorophyll-a fluorescence. The distributions of gelatinous zooplankton and fish tended to follow isopycnals that converged at the front. Taken together, this body of work shows common 5-10 meter scale vertical extent of many planktonic taxa despite the dramatic differences in hydrographic properties.

Pelagic Nutrient Cycles

Pelagic Nutrient Cycles
Author: Tom Andersen
Publisher: Springer Science & Business Media
Total Pages: 291
Release: 2013-06-29
Genre: Science
ISBN: 3662034182

An analysis of the interactions between pelagic food web processes and element cycling in lakes. While some findings are examined in terms of classical concepts from the ecological theory of predator-prey systems, special emphasis is placed on exploring how stoichiometric relationships between primary producers and herbivores influence the stability and persistence of planktonic food webs. The author develops simple dynamic models of the cycling of mineral nutrients through plankton algae and grazers, and then goes on to explore them both analytically and numerically. The results thus obtained are of great interest to both theoretical and experimental ecologists. Moreover, the models themselves are of immense practical use in the area of lake management.

Ecosystems of California

Ecosystems of California
Author: Harold Mooney
Publisher: Univ of California Press
Total Pages: 1008
Release: 2016-01-19
Genre: Nature
ISBN: 0520278801

This long-anticipated reference and sourcebook for CaliforniaÕs remarkable ecological abundance provides an integrated assessment of each major ecosystem typeÑits distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of CaliforniaÕs ecological patterns and the history of the stateÕs various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the stateÕs ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of CaliforniaÕs environment and curious naturalists.

Understanding Apex Predator and Pelagic Fish Habitat Utilization in the California Current System by Integrating Animal Tracking With in Situ Oceanographic Observations

Understanding Apex Predator and Pelagic Fish Habitat Utilization in the California Current System by Integrating Animal Tracking With in Situ Oceanographic Observations
Author:
Publisher:
Total Pages: 10
Release: 2007
Genre:
ISBN:

This study will develop a dynamic, ecosystem-based approach to map and understand habitat utilization by top predators in the CCS. Specifically, our objectives are: (1) To map critical habitats of predators in the California Current System; (2) To link the movement patterns of these predators to physical and biological ocean features, in order to: 1. determine how ocean dynamics act to aggregate diverse organisms; 2. define the stability and community structure around biological hot spots; 3. define the persistence of hot spots in space and time; 4. examine the relationships among different species in the context of habitat utilization; 5. identify the influence of top down and bottom up processes and their influence on dynamics of hot spots; (3) To map habitat distribution of commercially-viable and threatened fish stocks in the CCS, based on predator distribution and behavior from tracking data; (4) To quantify the seasonal and inter-annual variability of mesoscale ocean features (potential hot spots) in the CCS, from remotely sensed and in situ data; (5) To contribute a significant quantity of high-resolution in situ oceanographic data from animal tags to coastal and global ocean observing programs; (6) To provide critical advice to fisheries managers on the distribution of commercially-viable fish stocks in relation to oceanographic variability; (7) To develop and test models that allow for the prediction of animal abundance and distribution based on the physical environment.

Trophic Dynamics of Marine Nekton and Zooplankton Within the Northern California Current Pelagic Ecosystem

Trophic Dynamics of Marine Nekton and Zooplankton Within the Northern California Current Pelagic Ecosystem
Author: Todd William Miller
Publisher:
Total Pages: 228
Release: 2006
Genre: Food chains (Ecology)
ISBN:

The Northern California Current (NCC) ecosystem exhibits extreme seasonal, interannual and interdecadal shifts in the abiotic environment and shifts in primary and higher production. This variability is also apparent in the spatial structure of the ecosystem with nearshore-shelf waters (