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Full-Text Articles in Marine Biology

Resolving Variability In Size Structure In An Individual-Based Model For The North Pacific Krill, Euphausia Pacifica, Roxanne Robertson Jan 2021

Resolving Variability In Size Structure In An Individual-Based Model For The North Pacific Krill, Euphausia Pacifica, Roxanne Robertson

Cal Poly Humboldt theses and projects

Individual-based models (IBMs) have emerged as a powerful tool for ecological research and are particularly well suited to studies of plankton ecology. In this thesis, I develop an IBM for the North Pacific krill, Euphausia pacifica, with the goal of replicating observed variability in size-structure in the northern California Current Ecosystem. Krill, and E. pacifica in particular, are central to the structure and function of the California Current Ecosystem. Their response to environmental forcing translates climate variability to higher trophic levels and underpins broader ecosystem responses. Recent observations indicate environmental and climate-related shifts in E. pacifica size distributions, which …


Response Of Coastal Ichthyoplankton Assemblages Off Northern California To Seasonal Oceanographic And Climate Variability, Blair M. Winnacott Jan 2021

Response Of Coastal Ichthyoplankton Assemblages Off Northern California To Seasonal Oceanographic And Climate Variability, Blair M. Winnacott

Cal Poly Humboldt theses and projects

This study analyzed samples collected along the Trinidad Head Line (41°N) to characterize variability in the ichthyoplankton assemblage in coastal waters off northern California from late 2007 through 2019, a period during which a major marine heatwave (MHW; late 2014-16) strongly perturbed the ecosystem. I augmented visual identification with genetic techniques to resolve the species composition of visually cryptic larval rockfishes (Sebastes spp.). While taxonomic composition off northern California was largely similar to studies off Oregon and Washington, and cross-shelf structure and seasonal patterns in species’ abundance were generally consistent with the distribution and phenology of parental stocks, interannual …


Changes In Prey Mortality: The Efects Of Multiple Predators And Temperature On California Mussels, Wesley Hull Jan 2020

Changes In Prey Mortality: The Efects Of Multiple Predators And Temperature On California Mussels, Wesley Hull

Cal Poly Humboldt theses and projects

Organisms serve as prey to a variety of predators within natural systems, detecting threats through physical and chemical means. While predator feeding behavior is also affected by the presence of other predators, it is unclear whether differing modes of detection have similar effects on predator feeding behavior. In rocky intertidal zones in northern California, the California mussel (Mytilus californianus) is a competitively dominant foundation species consumed by a variety of predators. I quantified the individual and combined effects of ochre star (Pisaster ochraceus) and rock crab (Romaleon antennarium) predation on mussels by implementing mussel …


Spatial Variability In Recruitment Of Chilipepper Rockfish (Sebastes Goodei) In The California Current System, Laura K. Solinger Jan 2019

Spatial Variability In Recruitment Of Chilipepper Rockfish (Sebastes Goodei) In The California Current System, Laura K. Solinger

Cal Poly Humboldt theses and projects

Properly describing variability in population dynamics (e.g., growth, fecundity, recruitment) is expected to improve management of important fisheries stocks (Maunder & Piner, 2014). As recruitment to most fish stocks is determined during early life history stages (Houde, 1997; Iles & Beverton, 2000), and early life history stages are influenced by oceanographic conditions (Bjorkstedt et al. 2002; Laidig, 2010), understanding how environmental stochasticity influences recruitment deviations has potential to improve estimates of stock productivity and how productivity might change over time to support more effective management. Chilipepper Rockfish (Sebastes goodei) are an important commercial species that is managed as …


The Effects Of Ocean Acidification And Reduced Oxygen On The Behavior And Physiology Of Juvenile Rockfish, Corianna H. Flannery Jan 2018

The Effects Of Ocean Acidification And Reduced Oxygen On The Behavior And Physiology Of Juvenile Rockfish, Corianna H. Flannery

Cal Poly Humboldt theses and projects

As climate change progresses, the frequency and duration of upwelling events that bring low pH, low dissolved oxygen (DO) water to nearshore habitats are expected to increase. In addition, long-term global changes in ocean pH and DO are expected to occur within the next few decades to centuries. Locally, there have been documented reductions in near-shore pH along with the expansion of oxygen minimum zones within the California Current System. However, very few studies have investigated the potential interactive effect of these stressors on temperate reef fish. For this thesis, two sets of laboratory experiments were conducted to determine the …


Multiscale Habitat Suitability Modeling For Canary Rockfish (Sebastes Pinniger) Along The Northern California Coast, Portia N. Saucedo Jan 2017

Multiscale Habitat Suitability Modeling For Canary Rockfish (Sebastes Pinniger) Along The Northern California Coast, Portia N. Saucedo

Cal Poly Humboldt theses and projects

Detailed spatially-explicit data of the potential habitat of commercially important rockfish species are a critical component for the purposes of marine conservation, evaluation, and planning. Predictive habitat modeling techniques are widely used to identify suitable habitat in un-surveyed regions. This study elucidates the predicted distribution of canary rockfish (Sebastes pinniger) along the largely un-surveyed northern California coast using data from visual underwater surveys and predictive terrain complexity covariates. I used Maximum Entropy (MaxEnt) modelling software to identify regions of suitable habitat for S. pinniger greater than nine cm in total length at two spatial scales. The results of …