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Declining oxygen is one of the most drastic changes in the ocean, and this trend is expected to worsen under future climate change scenarios. Spatial variability in dissolved oxygen dynamics and hypoxia exposures can drive differences in vulnerabilities of coastal ecosystems and resources, but documentation of variability at regional scales is rare in open-coast systems. Using a regional collaborative network of dissolved oxygen and temperature sensors maintained by scientists and fishing cooperatives from California, USA, and Baja California, Mexico, we characterize spatial and temporal variability in dissolved oxygen and seawater temperature dynamics in kelp forest ecosystems across 13° of latitude in the productive California Current upwelling system. We find distinct latitudinal patterns of hypoxia exposure and evidence for upwelling and respiration as regional drivers of oxygen dynamics, as well as more localized effects. This regional and small-scale spatial variability in dissolved oxygen dynamics supports the use of adaptive management at local scales, and highlights the value of collaborative, large-scale coastal monitoring networks for informing effective adaptation strategies for coastal communities and fisheries in a changing climate.

Molecular modeling of lipids has been hampered by the size of these complex, biologically important molecules. Yet, understanding the structure and energy (enthalpy) of large molecules is critical to identifying their function in chemical equilibrium and transition state theory. In this work, we use both experimental data and G4 computed results, to show that cis polyunsaturated lipids have helical conformers. We present linear functions for the enthalpy of formation ΔfH°298 and the Gibbs free energy of formation ΔfG°298 as a function of n, where n is the number of carbon atoms in a linear carboxylic acid chain. Taking ΔfH°298 of a saturated acid as a starting point, we add the enthalpy of hydrogenation ΔhydH°298 at appropriate locations on the carbon chain to model polyunsaturated fatty acids. For example, taking eicosanoic acid (C20) as a saturated starting point, we add four enthalpies of cis-dehydrogenation (ΔhydH°298) to obtain arachidonic acid (eicosa-5Z,8Z,11Z,14Z-tetraenoic acid). We compare Gaussian-4 computational results, to show evidence of helical structure. We conclude that fatty acids can have helical conformers facilitating a broad range of biological functions. Keywords: G4 Calculations, Helix, Lipid, Molecular Structure, Thermochemistry

Significance The pH of the global ocean is decreasing due to the absorption of anthropogenically emitted CO2, causing ocean acidification (OA). OA negatively impacts marine shellfish and threatens the continuing economic viability of molluscan shellfish aquaculture, a global industry valued at more than 19 billion USD. We identify traits linked to growth and lipid regulation that contribute tolerance to OA in abalone aquaculture, with broader implications for adaptation efforts in other shellfish species. We also identify evolved heritable variation for physiological resilience to OA that may be exploited in commercial and restoration aquaculture breeding programs to offset the negative consequences of continuing climate change., Ocean acidification (OA) poses a major threat to marine ecosystems and shellfish aquaculture. A promising mitigation strategy is the identification and breeding of shellfish varieties exhibiting resilience to acidification stress. We experimentally compared the effects of OA on two populations of red abalone (Haliotis rufescens), a marine mollusc important to fisheries and global aquaculture. Results from our experiments simulating captive aquaculture conditions demonstrated that abalone sourced from a strong upwelling region were tolerant of ongoing OA, whereas a captive-raised population sourced from a region of weaker upwelling exhibited significant mortality and vulnerability to OA. This difference was linked to population-specific variation in the maternal provisioning of lipids to offspring, with a positive correlation between lipid concentrations and survival under OA. This relationship also persisted in experiments on second-generation animals, and larval lipid consumption rates varied among paternal crosses, which is consistent with the presence of genetic variation for physiological traits relevant for OA survival. Across experimental trials, growth rates differed among family lineages, and the highest mortality under OA occurred in the fastest growing crosses. Identifying traits that convey resilience to OA is critical to the continued success of abalone and other shellfish production, and these mitigation efforts should be incorporated into breeding programs for commercial and restoration aquaculture.

The prevalence of disease-driven mass mortality events is increasing, but our understanding of spatial variation in their magnitude, timing and triggers are often poorly resolved. Here, we use a novel range-wide dataset comprised 48 810 surveys to quantify how sea star wasting disease affected Pycnopodia helianthoides , the sunflower sea star, across its range from Baja California, Mexico to the Aleutian Islands, USA. We found that the outbreak occurred more rapidly, killed a greater percentage of the population and left fewer survivors in the southern half of the species's range. Pycnopodia now appears to be functionally extinct (greater than 99.2% declines) from Baja California, Mexico to Cape Flattery, Washington, USA and exhibited severe declines (greater than 87.8%) from the Salish Sea to the Gulf of Alaska. The importance of temperature in predicting Pycnopodia distribution rose more than fourfold after the outbreak, suggesting latitudinal variation in outbreak severity may stem from an interaction between disease severity and warmer waters. We found no evidence of population recovery in the years since the outbreak. Natural recovery in the southern half of the range is unlikely over the short term. Thus, assisted recovery will probably be required to restore the functional role of this predator on ecologically relevant time scales.

California abalone Haliotis spp., listed as species of concern, have been slow to recover, after 22 years of fishery closure, or are not recovering at all because of low-density populations and recruitment failure. It is not known if there is successful recruitment in populations in the wild in Southern California. This work examines, for the first time, whether newly settled abalones (

Predator–prey interactions exist on a variety of spatial and temporal scales; one of the earliest measurable responses to changes in these interactions is behavior. We examined the behavior of southern California kelp forest predators in response to a concentrated increase in the abundance of abalone during a restoration stocking experiment. We tested three hypotheses: (1) kelp forest predator density will increase following abalone stocking, (2) variations in predator characteristics will create an unequal impact on abalone, and (3) predation intensity will be greatest early in the experiment. Octopus discovered and exploited the influx of prey within the first week following stocking; their densities surged and then returned to pre-stocking levels after 2 months. This was not observed with any other predator. Damage from crustacean, fish, and octopus predation was observed on the recovered abalone shells, but were not correlated with predator densities. A larger percentage of recovered small shells had evidence of crustacean and fish predation, indicating there may be size-specific impacts of predators on abalone. Our results demonstrate that restoration stocking experiments can quantitatively test the predatory community’s response to reintroductions, as well as predation risk of newly stocked prey species when exposed to a diverse suite of predators.

Restoration and modeling of endangered species is challenging when the available data are sparse and the environmental conditions are stochastic. Using white abalone Haliotis sorenseni, a critically endangered marine broadcast spawner with spatially patchy remnant populations in southern California (USA), as an example, we developed an individual-based model that describes density-, temperature-, and habitat-dependent biological processes. Using the model, we evaluated hypothetical stocking strategies including spatial distribution and size of stocked abalone and initial density of resident abalone. Our results show that stocking strategies for the modeled white abalone populations benefited most when stocking locations had resident abalone and when stocked abalone were large in size. We also examined the potential influence of the spatial structure of the habitat (i.e. percentage of suitable habitat and spatial distribution of habitat cells), ocean warming, and poaching on restoration outcomes. We found that the percentage of suitable habitat greatly affected population dynamics, with more suitable habitat resulting in a slower decline in population growth and recruitment, as well as a higher and more stable proportion of intermediate-sized abalone. The spatial distribution (random or clustered) of habitat cells and of stocked abalone had less of an impact on model outcomes. Elevated temperature and poaching both had strong negative impacts on abalone population growth in the model. Given the spatial structure of the habitat and population, ocean warming and poaching are considered critical factors in the development of restoration strategies for endangered broadcast spawners.

Marine kelp forests, among the most productive ecosystems on our planet, are in danger. The increase in the frequency and intensity of extreme climatic events such as marine heat waves is compromising kelp forests' capacity to produce goods and services (such as biomass of commercial fisheries, coastal protection, nutrient cycling, carbon sequestration, and recreational opportunities) that are worth billions of dollars to humanity. However, despite increasing climate-change advocacy and the overwhelming evidence demonstrating social and ecological impacts of climate change, political denial and inaction are jeopardizing society's ability to respond adequately to the multifaceted consequences of the accelerating pace of climate-driven loss of marine forests.

In the northeast Pacific, the sea urchins Mesocentrotus franciscanus and Strongylocentrotus purpuratus are ecologically important species that play a dominant role in intertidal and subtidal rocky ecosystems. M. franciscanus are the basis for important commercial fisheries and serve as an indigenous traditional food resource as well as model species in developmental research. Both species are important ecosystem structuring species (ecosystem engineers) that control the flow of resources within marine communities. Recent work continues to reveal factors that shape their population dynamics, role in the ecosystem, and how climate change may alter both of these. Over the past decade, the coast-wide collapse of the predatory sea star Pycnopodia helianthoides and a massive, long-lasting marine heat wave corresponded with historically stable, kelp forests transitioning to species-poor barrens dominated by M. franciscanus and S. purpuratus. In contrast, some sea urchin populations have experienced declines due to disease in southern California, toxins in northern California, expanding populations of the sea otter Enhydra lutris in Alaska and British Columbia or the recovery of sea urchin predators in California's marine protected areas. Such radical changes in population dynamics have direct and indirect consequences for the productivity and diversity of kelp forests. In northern California, the recent destruction of the kelp forest by sea urchins has had cascading impacts resulting in the collapse of both the commercial M. franciscanus and recreational red abalone, Haliotis rufescens, fisheries. Currently, there are efforts to ameliorate the proliferation of barrens or poor quality of sea urchin roe include kelp restoration through culling, sea urchin ranching, and plans for rebuilding populations of sea urchin predators. A looming question for both sea urchins and kelp forests is how climate change will affect reproduction and recruitment via larval production, development, ocean transport, budding, survival and settlement, and how these processes vary across space and time. Research continues to reveal both physiological sensitivity and resilience to effects of climate change of sea urchins, such as warming, food deficiencies, hypoxia, salinity, low pH, and ocean circulation. How both climatic effects and the ecological factors that impact the dynamics of sea urchin populations, and the ecosystems they control, remains a critical area of research for these ecologically, culturally, and commercially important species.

We have computed the Gaussian G4 structures, enthalpies of formation, and Gibbs free energies of formation of four trans-1,2-dialkylcyclopentanes. Aside from their intrinsic interest as products of petroleum refining, we wish to use these simple trans-1,2-dialkylcyclopentanes as a database in the study of larger, more complicated molecules like prostanoic acid and its derivatives, the prostaglandins.

Extreme climatic events have recently impacted marine ecosystems around the world, including foundation species such as corals and kelps. Here, we describe the rapid climate-driven catastrophic shift in 2014 from a previously robust kelp forest to unproductive large scale urchin barrens in northern California. Bull kelp canopy was reduced by >90% along more than 350 km of coastline. Twenty years of kelp ecosystem surveys reveal the timing and magnitude of events, including mass mortalities of sea stars (2013-), intense ocean warming (2014–2017), and sea urchin barrens (2015-). Multiple stressors led to the unprecedented and long-lasting decline of the kelp forest. Kelp deforestation triggered mass (80%) abalone mortality (2017) resulting in the closure in 2018 of the recreational abalone fishery worth an estimated $44 M and the collapse of the north coast commercial red sea urchin fishery (2015-) worth $3 M. Key questions remain such as the relative roles of ocean warming and sea star disease in the massive purple sea urchin population increase. Science and policy will need to partner to better understand drivers, build climate-resilient fisheries and kelp forest recovery strategies in order to restore essential kelp forest ecosystem services.

White abalone Haliotis sorenseni was listed as endangered in 2001 because of severe declines throughout southern California due to overfishing. Populations continue to decline despite the closure of the fishery in 1996. There has been little to no evidence of recruitment in southern California from population surveys and in artificial reefs targeting white abalone recruitment since the listing of the species. A 13-y time series of white abalone abundance in prime habitat, surveyed with a remote-operated vehicle, was used in a population viability analysis to quantify: (1) the population decline and (2) the time to reach a quasi-extinction threshold. The annual decline in the population is 12%, which is comparable to adult natural mortality rates for abalone species. The quasi-extinction threshold of 1,000 individuals is met within 15 y. These results confirm that the white abalone populations in southern California are at high risk of extinction, and highlight the importance of active stocking and restoration for the species. To inform restoration, a deterministic density-dependent size-based matrix model was developed to investigate different stocking scenarios, incorporating an innovative method for modeling low populations by setting the reproductive term as a function of adult density to mimic a reproductive Allee effect. A minimum density of 0.14 abalone/m2 of stocked juveniles led to a maximum population growth rate (λ) of more than or equal to 1 for the model population within 10 y but that recovery was poor (mean λ15–20 ≤ 1.0) over time if the level of juvenile stocking was less than 0.23 abalone/m2 in the model population. The innovative approach of incorporating adult density into the reproductive term in the model quantitatively shows how low population densities can impact threatened and endangered species, and may be widely used for other species. These results can not only help guide stocking strategies but also allow for the quantitative evaluation of white abalone under the guidance of the IUCN Red List of Threatened Species, suggesting that white abalone should be considered Critically Endangered.

A restoration program including wild population surveys, captive breeding, health monitoring, recovery site preparation, and recovery modeling has been implemented to restore white abalone (Haliotis sorenseni) populations in California. White abalone once supported a lucrative fishery and are now endangered, nearing extinction at less than 1% of baseline abundances. Recent deep water surveys indicate that populations continue to decline with no signs of recruitment, despite the closure of the fishery in 1996. Four sites with artificial reefs (n=12/site) in optimal white abalone habitat were established. No wild white abalone have been found at these sites. Captive abalone were spawned in the spring of each year from 2012 to 2015. Each year, the production of 1-y-old abalone has increased in the captive breeding program from approximately 20 in 2012, to 150 in 2013 and an estimated 2,000 in 2014. In 2015, the breeding program reached two milestones: (1) most successful spawning season to date and ...

Recruitment is a central question in both ecology and fisheries biology. Little is known however about early life history stages, such as the larval and newly settled stages of marine invertebrates. No one has captured wild larval or newly settled red abalone (Haliotis rufescens) in California even though this species supports a recreational fishery. A sampling program has been developed to capture larval (290 µm), newly settled (290–2,000 µm), and juvenile (2–20 mm) red abalone in northern California from 2007 to 2015. Plankton nets were used to capture larval abalone using depth integrated tows in nearshore rocky habitats. Newly settled abalone were collected on cobbles covered in crustose coralline algae. Larval and newly settled abalone were identified to species using shell morphology confirmed with genetic techniques using polymerase chain reaction restriction fragment length polymorphism with two restriction enzymes. Artificial reefs were constructed of cinder blocks and sampled each year ...

Understanding spatial and temporal patterns in the recruitment of marine invertebrates with complex life histories remains a critical knowledge gap in marine ecology and fisheries. As marine invertebrates are facing multiple stressors from overfishing and climatic stress, it is important to evaluate the conditions that facilitate recruitment in low-density populations. The red abalone Haliotis rufescens historically supported an economically important fishery in California, but the fishery was sequentially closed as stocks declined, and the last fished area was closed in 2018 following the collapse of the kelp forests in Northern California. Here, red abalone recruitment was evaluated annually from 2012 to 2016 and monthly from 2016 to 2017 in Central California where red abalone naturally occur in highly aggregated but low-density populations because of sea otter predation. Trends in wind-driven upwelling, temperature, wave forces, and food resources (kelp) were evaluated over the same time period as factors that could affect recruitment patterns. Recruitment was annually consistent except in 2015, when recruitment declined by 76%, likely because of reproductive failure during the second year of the North Pacific marine heat wave. The monthly recruitment assessment was the first field assessment of red abalone recruitment over a full year, and it showed that red abalone can recruit year-round. There were no clear recruitment patterns associated with seasonal wind-driven upwelling or relaxation patterns, and kelp density was constant over the study period; however, conditions at the study sites included three key features that may provide optimal conditions for consistent recruitment: (1) spatial abalone aggregation, (2) a sheltered embayment that may retain larvae, and (3) persistent algal food resources. These results can inform statewide and global abalone recovery and management programs.

Many curves have been proposed and debated to model individual growth of marine invertebrates. Broadly, they fall into two classes, first order (e.g. von Bertalanffy) and sigmoidal (e.g. Gompertz). We provide an innovative approach which demonstrates that the growth curves are not mutually exclusive but that either may arise from a simple three-stage growth model with two steps (k1 and k2) depending on the ratio of the growth parameters . The new approach predicts sigmoidal growth when is close to 1, but if either growth from stage A to stage B or B to C is fast relative to the other, the slower of the two steps becomes the growth limiting step and the model reduces to first order growth. The resulting curves indicate that there is a substantial difference in the estimated size at time t during the period of active growth. This novel two-step rate model generates a growth surface that allows for changes in the rate parameters over time as reflected in the new parameter n(t) = k1(t) - k2(t). The added degree of freedom brings about individual growth trajectories across the growth surface that is not easily mapped using conventional growth modeling techniques. This two (or more) stage growth model yields a growth surface that allows for a wide range of growth trajectories, accommodating staged growth, growth lags, as well as indeterminate growth and can help resolve debates as to which growth curves should be used to model animal growth. This flexibility can improve estimates of growth parameters used in population models influencing model outcomes and ultimately management decisions.=

Identifying appropriate ecological conditions for population restoration is important for endangered species such as black abalone (Haliotis cracherodii) in California, but limited information exists regarding restoration locations. Using a combination of ancient and historical archaeological data and modern commercial fishing records, four optimal locations for restoration based on past relative abundances of black abalone were identified: north-western, north-eastern, and south-central San Miguel Island and western San Nicolas Island. These locations around California's Channel Islands have supported dense black abalone populations for at least 10 000 years and may offer optimal environmental conditions to enhance the success of black abalone restoration. The strategy outlined here illustrates the promise of integrating prehistoric, historical, and modern fishery data to inform restoration of threatened and endangered abalone, oysters, and other shellfish around the world. Copyright © 2015 John Wiley & Sons, Ltd.

Ocean acidification (OA) increasingly threatens marine systems, and is especially harmful to calcifying organisms. One important question is whether OA will alter species interactions. Crustose coralline algae (CCA) provide space and chemical cues for larval settlement. CCA have shown strongly negative responses to OA in previous studies, including disruption of settlement cues to corals. In California, CCA provide cues for seven species of harvested, threatened, and endangered abalone. We exposed four common CCA genera and a crustose calcifying red algae, Peyssonnelia (collectively CCRA) from California to three pCO2 levels ranging from 419–2,013 µatm for four months. We then evaluated abalone (Haliotis rufescens) settlement under ambient conditions among the CCRA and non-algal controls that had been previously exposed to the pCO2 treatments. Abalone settlement and metamorphosis increased from 11% in the absence of CCRA to 45–69% when CCRA were present, with minor variation among CCRA genera. Though all CCRA genera reduced growth during exposure to increased pCO2, abalone settlement was unaffected by prior CCRA exposure to increased pCO2. Thus, we find no impacts of OA exposure history on CCRA provision of settlement cues. Additionally, there appears to be functional redundancy in genera of CCRA providing cues to abalone, which may further buffer OA effects.

Extreme environmental events that trigger mass mortalities are making fisheries management more challenging. Catastrophic events can have unforeseen impacts on fished resources outside the scope of fishery models and management plans. Mass mortality events (MME) that rapidly reduce densities can decrease the productivity of Haliotis spp. abalone and other benthic free spawning marine invertebrates that require minimum densities for reproductive success. Density-based indicators using fishery-independent measures of density on the fishing grounds serve as an important alternative source of information for management. In northern California, this approach is used to manage the recreational red abalone Haliotis rufescens fishery using densities at key fished sites to guide management. In 2011, a harmful algal bloom (HAB) impacted the southern region of the fishery providing a test of the density-based indicators. Surveys following the HAB revealed a 35% decrease in average density in the southern portion and a decrease in the fishery overall. Empirical fishery-independent density surveys could be used in a range of fisheries for detection of impacts from nonclimate-related stressors such as overfishing and pollution as well as climate-related stressors such as warming, acidification, hypoxia, and disease bolstering climate-ready management. Ecosystem indicators may also be used as early indicators of future changes to productivity. As climate change is predicted to increase the intensity and frequency of MME, managers will need to use sensitive indicators to inform effective climate-ready management responses.

Nearshore kelp forest ecosystems are highly vulnerable to climate change and ocean warming, which can alter community dynamics and change the trajectory of species recovery in unpredictable ways. Abalone (Haliotis spp.) populations in the Southern California Bight (SCB) are still recovering from a combination of overfishing and disease, despite the closure of the fisheries 20 years ago and active restoration programs for abalone species in the region. For this study, abalone recruitment and sea urchin populations were surveyed in artificial habitats (16–22 m) across a spatial and temporal climatic gradient in southern California from 2010 to 2017 to inform the development of climate-ready abalone restoration programs. The SCB encompasses warm and cool islands, and experienced two periods of ocean conditions—cool (2010–2013) and warm ocean conditions (2014–2016). Dive surveys of the artificial habitats revealed that juvenile abalone recruitment remained low during the study period, suggesting that recovery is slow. Warm-water years favored recruitment of juvenile pink (Haliotis corrugata) and green abalone (Haliotis fulgens), with the highest abalone recruitment observed at Catalina Island. Endangered white abalone (Haliotis sorenseni) were not observed despite placing the artificial habitats in suitable deep rocky reefs, which is further evidence supporting their endangered species status. The coolest site, San Diego, had little abalone recruitment, with a few juvenile red abalone (Haliotis rufescens) and threaded (Haliotis kamtschatkana) abalone present. Sea urchin abundance and diversity increased during the warm period, with the largest increase at Catalina Island. During the warm period, Coronado sea urchin (Centrostephanus coronatus) increased in abundance, coincident with a decrease in the commercially valuable temperate red sea urchin (Mesocentrotus franciscanus). Potential shifts in the sea urchin assemblage to warm-water sea urchins may negatively impact recovering abalone populations and the red sea urchin fishery. Climate-ready abalone restoration will require ecosystem-based monitoring, tracking on not only abalone recruitment but also sea urchins, algal abundances, ocean temperature, and kelp forest communities as climate change may lead to complex and unexpected ecosystem interactions.

Historically, Point Loma had the highest fishery landings of pink abalone (Haliotis corrugata Wood 1828) along the California coast. The current status of the population in this key location is described using population and aggregation surveys from 2004 to 2007. We developed a size-based matrix model to assess the recovery potential of this low-density population. We incorporated fecundity parameters into the model, modified by empirical nearest-neighbor distance, aggregation size, sex ratio, and size-frequency data, to evaluate their influence on the population growth rate. We found the density of the population (∼170 abalone/ha) is an order of magnitude less than the minimum spawning density (2,000 abalone/ha) used by the California Department of Fish and Wildlife for abalone management. The average aggregation size was ∼2 abalone, and more than 50% of the abalone were solitary (no neighbors within a 2.5-m distance). The average nearest-neighbor distance was greater than 5 m in all 3 y, corres...

Population declines of pink (Haliotis corrugata) and green (Haliotis fulgens) abalone in southern California forced the closure of the fisheries in 1995. Overfishing was the main factor contributing to decreasing landings, and in 2004 both pink and green abalone were identified as species of concern. Translocation of adults, moving solitary abalone together to create dense aggregations, is one of the strategies that has been proposed to overcome Allee effects and to enhance spawning success and recovery. Pink (n = 35) and green (n = 113) abalone were tagged and translocated to recovery sites with preexisting pink (n = 13) and green (n = 26) abalone. Translocation and preexisting abalone were tagged and monitored to determine their long-term survival, persistence at the site, and movement at 2 islands in southern California. The mortality associated with the tagging and translocations was low (

Red abalone (Haliotis rufescens) were assessed inside and outside a “de facto” reserve before fishing, after 3 and then 6 years of fishing. In just 3 years, there was a 65% decline (p 72% decline). Before fishing began, the intertidal density at the reserve was 86% greater (p = 0.001) than at a nearby fished site, however after 3 years of fishing there was no difference (p = 0.764). Abalone fishing report cards revealed a 950% increase in local catch once the reserve site was opened, however after just 1.5 years of fishing, catch declined sharply (59%) compared to the previous year. In 3 years, mean abalone catch per hour declined significantly (p

Northern abalone (Haliotis kamtschatkana kamtschatkana) is a federally listed species of concern. The status of northern abalone and the characteristics of the habitats they associate with were determined showing that northern abalone have declined dramatically in Washington State with present day abundances

Changes in ocean temperature can have direct and indirect effects on the population dynamics of marine invertebrates. We examined the impacts of warm water, starvation, and disease on reproduction in red abalone (Haliotis rufescens). We found that sperm production was highly sensitive to warm water and starvation, suggesting there may be a dramatic temperature threshold above which sperm production fails. Wild males from northern (72%) and southern (81%) California had sperm. In contrast, only 30% of the males exposed to warm water (18C) for 6 mo or starvation for 13 mo had sperm, with spermatogenesis dropping dramatically from 300,000 presperm cells/mm 3 (wild) to 46,000 presperm cells/mm 3 (warm water) and 84,000 presperm cells/mm 3 (starvation). In a longer warm-water experiment (12 mo), males had total reproductive failure in temperatures greater than 16C, irrespective of food treatment. Egg production was less sensitive to warm water, but was impacted more by starvation, especially food quantity relative to quality. Wild females from northern (97%) and southern (100%) California had mature oocytes averaging 3 million eggs and 21 million eggs, respectively. Females exposed to 18C water for 6 mo had diminished fecundity, averaging only 400,000 mature eggs whereas females in the starvation experiment did not produce any mature eggs. Normal sperm and egg production was found in abalone testing positive for Rickettsiales-like-prokaryote (RLP), the agent of Withering Syndrome in cool water. However, abalone with RLP also exposed to warm water developed the disease withering syndrome and did not produce any mature gametes. The temperature-mediated lethal and sublethal effects on red abalone reproduction described here, combined with temperature's known impacts on abalone growth, kelp abundance, and disease status, clearly demonstrate population-level consequences. We suggest that temperature needs to be explicitly incorporated into red abalone recovery and management planning, because California's ocean has warmed and is predicted to warm in the future.

Eggs-per-recruit (EPR) models are widely used for management of invertebrate fisheries to provide guidance to managers about the magnitude of egg production for a given level of instantaneous annual fishing mortality (F). We constructed a deterministic size-based EPR model that utilizes size-specific natural mortality rates and egg production for red abalone Haliotis rufescens in California. We analyzed the sensitivity of the model to alterations in biological parameters, modeled the effect of incidental mortality of sublegal individuals on EPR, and modeled the effects of various management actions, including incorporation of a slot size limit, incorporation of a harvest refugium, and alternative legal minimum size limits. Model results were more sensitive to alterations in growth parameters and lower mortality estimates than to changes in upper mortality estimates or fecundity parameters. When F increased from 0.0 to 0.1 per year, EPR exhibited a large decline from 100% to 70%. Only the incorporation of a harvest refugium and an increase in the minimum size limit produced increases in the percent of maximum EPR. Implementing a slot limit of 152.4-203.2 mm maximum shell length (MSL) decreased the EPR value, indicating the importance of egg production by red abalone that are smaller than the current minimum size limit of 177.8 mm MSL. Because of the sensitivity of model predictions to changes in certain biological parameters, we recommend caution when applying EPR models to management, particularly for regions without spatially explicit parameter values. Despite this sensitivity, EPR models provide a heuristic framework for exploring the potential impacts of proposed fishery management strategies (e.g., harvest refugia), establishing biological reference points, examining how spatial and temporal variability in biological parameters affects egg production, and providing a guide for prioritizing research to improve data quality used for red abalone management.

We estimate annual growth and mortality of red abalone, Haliotis rufescens, in northern California using tag recapture data applied to multiple growth and mortality models. We investigate seven growth models of the form, Lt+1 ¼ Lt + f ðLtÞ; where Lt is the shell length at tagging (time t), Lt+1, is the shell length one year later, and the function f(Lt )i s a model of the change in length DL. Abalone are drawn from a broad range of sizes (shell lengths 5-222 mm) tagged and recaptured one year later (n ¼ 231) in the Point Cabrillo Reserve in northern California. We present the results for seven growth models, rank the fit of the models (using the sum of the squared residuals) selecting the Richards, Gaussian, Ricker, and von Bertalanffy models (in that order) as most appropriate for these variable growth data. The von Bertalanffy model yields the shortest time to fishery (recreational legal size is 178 mm) as it slightly overestimates early growth. The Ricker model yields the longest time to enter the fishery underestimating early growth. We present a table of abalone sizes as a function of time for the Gaussian model, from which we estimate the number of years to grow into the fishery (12.0 ± 1 y). Because differences among the applicable models are not great, we use the growth parameters generated by the simple von Bertalanffy model (LN and K )t o estimate mortality. The results are consistent among our five mortality estimates ranging from 0.11-0.23 per year. Estimates of the number of years to enter the fishery and mortality estimates, as well as knowledge of how model selection can influence these estimates, is important for fishery management. Informed fishery management for red abalone is critical because the fishery in northern California is the last open abalone fishery in the state.

Estimates of size-specific mortality were made for red abalone, Haliotis rufescens, from mark-recapture data for three size classes at six sites in California. Instantaneous mortality for the smallest size class (≤100 mm) was 0.67 y−1 (0.52–0.84 y−1, mean ± S.E.) to 1.02 y−1 (0.84–1.24 y−1, mean ± S.E.) and decreased with increasing size in both northern and southern California. Mortality was spatially variable for legal size abalone (>178 mm), 0.05 y−1 (0.0–0.14 y−1, mean ± S.E.) to 1.35 y−1 (1.17–1.56 y−1, mean ± S.E.) in northern California and varied temporally in southern California, 0.27 y−1 (0.15–0.42 y−1, mean ± S.E.) to 0.89 y−1 (0.73–1.08 y−1, mean ± S.E.). Estimates of fishing mortality were 0.97 y−1 (±0.21S.E.) and 1.29 y−1 (±0.17S.E.) at two sites in northern California. Understanding the spatial and temporal dynamics of mortality estimates is critical for fishery management and conservation.

Lingcod, Ophiodon elongatus Girard, have a 3-month pelagic larval stage and are an important recreational and commercial species on the west coast of North America. Cytochrome-c oxidase I sequences from tissue samples were used to characterize population structure and infer patterns of gene flow from California to Alaska. No significant genetic structure was found when estimates of Wright’s FST (i.e., ΦST) were generated among all populations sampled. Nesting populations within regions, however, indicated that the inner coast of Washington State is distinct, a result corroborating previous allozyme work. Coalescent-based estimates of gene flow indicate that although migration can be high from an evolutionary perspective, nearly half of all comparisons among populations showed no gene flow in at least one direction. From an ecological perspective, moderate migration rates (Nm < 10) among most populations provide surprisingly limited connectivity at large (∼ 1,000 km) and small (∼100 km) spatial scales. Coalescent-based estimates also show that gene flow between the inner and the outer coasts is asymmetric, a result consistent with prevailing surface currents. Because the expected inter-locus variances for coalescent-based estimates of gene flow are likely large, future work will benefit from analyses of nuclear DNA markers. However, limited demographic connectivity on large spatial scales may help explain why stock recovery has been uneven, with greater recovery in the northern (87% rebuilt) than in the southern (24% rebuilt) fishery region, supporting a regional management strategy. These results suggest that despite a 3-month pelagic larval stage, some areas may be effectively closed with respect to both population dynamics and fishery management issues.

Matrix models are critical for conservation planning of endangered species or any species with limited data. Sufficient growth data to construct growth-transition matrices required for size-structured population dynamics models may be lacking using traditional methods. We present a simple semi-empirical method for converting limited growth data into estimated transition probabilities required as elements in structured matrix models. Rather than approximating transition probabilities by counting actual transition frequencies between sparsely populated size classes, we assume that a selected function represents the entire data set, we obtain the model parameters by conventional curve fitting, and we construct the matrix model from the assumed model function. To illustrate the method, we use a sparse, scattered sample of growth data from the endangered white abalone. We use the slope and intercept of the von Bertalanffy model function to determine the growthtransition matrix elements, where the paucity and or scatter of the data preclude using the traditional counting method. The method we propose can accommodate both linear and non-linear mappings of size into growth rate, as we demonstrate with a Gaussian function which has been used to model growth of red abalone and red sea urchins. We illustrate how our method can convert confidence intervals from the model function into confidence intervals for the matrix elements. We suggest that this modelling procedure, which is simple to use and is suitable in data poor situations, will be broadly applicable for conservation practitioners in developing quantitative models to evaluate the population viability of endangered species.

The interactive effects of ocean climate and fishing pressure on nearshore rockfishes (Sebastes spp.) were examined using historical commercial passenger fishing vessel catch records from California. Principal component analysis was used to characterize the dominant patterns in catch per unit effort (CPUE) over time (1957–1999) and space (10′ latitude × 10′ longitude blocks). Ocean climate explained 60% of the variation in CPUE and revealed opposite responses in northern and southern California. In warm El Niño years, CPUE was 4.2 times higher in the north and 1.8 times lower in the south. CPUE responded similarly to low-frequency climate shifts by increasing in the north and decreasing in the south after 1976–1977. Four geographic regions responded as discrete units to environmental forcing and fishing intensity: North, Central, South, and Channel Islands. Over time, annual fish landings declined sharply in the South, with fishing effort remaining stationary and high relative to that in the other regions. In the North, landings and fishing effort remained tightly coupled, with effort an order of magnitude lower than in the South. These findings support a management strategy for nearshore rockfishes in California based on regional responses to ocean climate and fishing intensity.

Size, growth, and density have been studied for North American Pacific coast sea urchins Strongylocentrotus purpuratus, S. droebachiensis, S. polyacanthus, Mesocentrotus (Strongylocentrotus) franciscanus, Lytechinus pictus, Centrostephanus coronatus, and Arbacia stellata by various workers at diverse sites and for varying lengths of time from 1956 to present. Numerous peer-reviewed publications have used some of these data but some data have appeared only in graduate theses or the gray literature. There also are data that have never appeared outside original data sheets. Motivation for studies has included fisheries management and environmental monitoring of sewer and power plant outfalls as well as changes associated with disease epidemics. Studies also have focused on kelp restoration, community effects of sea otters, basic sea urchin biology, and monitoring. The data sets presented here are a historical record of size, density, and growth for a common group of marine invertebrates in intertidal and nearshore environments that can be used to test hypotheses concerning future changes associated with fisheries practices, shifts of predator distributions, climate and ecosystem changes, and ocean acidification along the Pacific Coast of North America and islands of the north Pacific. No copyright restrictions apply. Please credit this paper when using the data.

Mass mortalities in natural populations, particularly those that leave few survivors over large spatial areas, may cause long-term ecological perturbations. Yet mass mortalities may remain undocumented or poorly described due to challenges in responding rapidly to unforeseen events, scarcity of baseline data, and difficulties in quantifying rare or patchily distributed species, especially in remote or marine systems. Better chronicling the geographic pattern and intensity of mass mortalities is especially critical in the face of global changes predicted to alter regional disturbance regimes. Here, we couple replicated post-mortality surveys with preceding long-term surveys and historical data to describe a rapid and severe mass mortality of rocky shore invertebrates along the north-central California coast of the northeastern Pacific Ocean. In late August 2011, formerly abundant intertidal populations of the purple sea urchin (Strongylocentrotus purpuratus, a well-known ecosystem engineer), and the predatory six-armed sea star (Leptasterias sp.) were functionally extirpated from ~100 km of coastline. Other invertebrates, including the gumboot chiton (Cryptochiton stelleri) the ochre sea star (Pisaster ochraceus), and subtidal populations of purple sea urchins also exhibited elevated mortality. The pattern and extent of mortality suggest the potential for long-term population, community, and ecosystem consequences, recovery from which may depend on the different dispersal abilities of the affected species.

Abalone populations have declined dramatically in southern California. The white abalone ( Haliotis sorenseni) is now ( 2001) on the federal endangered species list. To aid in the restoration of white, pink ( H. corrugata), and green abalone ( H. fulgens), productive marine protected areas need to be selected. We used spatially explicit fishery data (1950–1995) to identify the most productive marine areas in southern California. To assess the role of existing marine protected areas we compared fishery-independent data (1983–2001) inside protected and fished areas. San Clemente Island produced the greatest cumulative catches of white, pink, and green abalone, the most white abalone per hectare of deep reef (25–65 m), and the most green abalone per kilometer of rocky shoreline. Santa Barbara Island, however, produced 10 times more pink abalone per hectare of kelp canopy, making this area an excellent candidate for restoration and protection. Pink abalone surveyed in the Kelp Forest Monitoring Program were most abundant at three sites surrounding Anacapa Island: (1) protected, (2) protected but less visible, and (3) fished. The protected sites, despite having lower abundances of pink abalone initially (1983), had significantly more abalone ( H = 9.0; df = 2; p = 0.011) than the nearby fished site over time. Size-frequency distributions revealed that the protected site had more (30%) commercial-size abalone (≥158 mm shell length) than the less visable site (6%) or the fished site (2%). Mean size was significantly larger at the protected site, yielding the highest estimate of biomass and potential egg production (2555 million eggs/site/year) of all the sites. Marine protected areas need to be selected and enforced so that abalone-restoration efforts can be enacted before remnant populations die. Restoration sites for a wide variety of depleted species can be selected based on previous levels of productivity identified by spatially explicit data. Resumen: Las poblaciones de abalon han declinado dramaticamente en California meridional. El abalon blanco ( Haliotis sorenseni) ahora (2001) esta en la lista federal de especies en peligro de extincion. Para ayudar a la restauracion del abalon blanco, el rosado ( H. corrugata) y el verde ( H. fulgens), se necesita seleccionar areas marinas protegidas productivas. Utilizamos datos de la industria pesquera (1950–1995) espacialmente explicitos para identificar las areas marinas mas productivas de California meridional. Para evaluar el papel de las areas marinas protegidas existentes comparamos datos independientes de la industria pesquera (1983–2001) dentro de areas protegidas y areas explotadas. La isla de San Clemente produjo las mayores capturas acumulativas de abalon blanco, rosado y verde, la mayor densidad de abalon blanco por hectarea de arrecife profundo (25–65 m), y la mayor densidad de abalon verde por kilometro de litoral rocoso. Sin embargo, la isla de Santa Barbara produjo 10 veces mas abalon rosado por hectarea de quelpo, haciendo esta area un candidato excelente para la restauracion y proteccion. Los abalones rosados examinados en el Programa de Monitoreo del Bosque de Quelpo fueron mas abundantes en tres sitios alrededor de la isla de Anacapa: (1) protegido, (2) protegido, pero menos visible y (3) explotado. Los sitios protegidos, a pesar de tener menor abundancia de abalon rosado inicialmente (1983), en el largo plazo tenian significativamente mas abalon ( H = 9.0; gl = 2; p = 0.011) que el sitio explotado proximo. La distribucion de frecuencias de tamano revelo que el sitio protegido tenia mas (30%) abalon de talla comercial (≥158 mm longitud de la concha) que el sitio no regulado (6%) o el sitio explotado (2%). La talla promedio era perceptiblemente mas grande en el sitio protegido, rindiendo la estimacion mas alta de biomasa y de produccion potencial de huevos (2555 millones de huevos/sitio/ano) comparadas con los otros sitios. Las areas marinas protegidas deben ser seleccionadas y reguladas para poder decretar esfuerzos de restauracion del abalon antes de que las poblaciones remanentes mueran. Los sitios de restauracion para una amplia variedad de poblaciones agotadas se pueden seleccionar con base en los niveles de la productividad anteriores identificados por datos espacialmente explicitos.

Toxic spills, hypoxia, disease outbreaks and toxin-producing algal blooms are all possible causes of mass mortality events, but in many cases it can be difficult to pinpoint the cause of death. Here we present a new approach that we name â ̃ forensic genomicsâ (tm), combining field surveys, toxin testing and genomic scans. Forensic genomics queries allele frequencies of surviving animals for signatures of agents causing mass mortality and, where genetic diversity is high, is uniquely suited to identify natural selection in action. As a proof of concept, we use this approach to investigate the causes of an invertebrate mass mortality event, and its genetic effects on an abalone population. Our results support that a harmful algal bloom producing a yessotoxin was a major causative agent to the event. © 2014 Macmillan Publishers Limited.

Marine protected areas (MPAs) designed to provide harvest refugia for red sea urchins ( Strongylocen- trotus franciscanus ) offer a unique opportunity to study the indirect effects of urchin fishing on subtidal communi- ties. Sea urchins may provide important cryptic microhabitat for juvenile abalone sheltering beneath urchin spines in shallow habitats worldwide. We investigated the abundance of juvenile (3-90 mm) red abalone, ( Haliotis rufescens ) and the rare flat ( � 90 mm) abalone ( H. walallensis ) on protected and fished rocky reefs in California. Abalone abundance surveys were conducted inside 24 � 30 m plots on three protected reefs with red sea urchins present and three fished reefs where red sea urchins were removed by commercial or experimental fishing. Signifi- cantly more juvenile abalone were found in 1996 and 1997 on protected reefs with urchins present than on fished reefs ( � 2 � 188, df � 1, p � 0.001). Juvenile red abalone abundance was not correlated with local adult red aba- lone abundance or habitat rugosity. One-third of the juveniles inside the MPAs were found under the urchins' spine canopy, as were a suite of unfished marine organisms. In the laboratory, juvenile abalone survived better ( � 2 � 7.31, df � 1, p � 0.01) in crab predation experiments in which red sea urchins were available as shelter. Fishing red urchins reduced structural complexity, potentially decreasing microhabitat available for juve- nile abalone. This example demonstrates how MPAs designed for one fished species may help other species, illus- trating their usefulness for ecosystem-based fishery management and marine conservation.