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Conservation aquaculture is becoming an important tool to support the recovery of declining marine species and meet human needs. However, this tool comes with risks as well as rewards, which must be assessed to guide aquaculture activities and recovery efforts. Olympia oysters (Ostrea lurida) provide key ecosystem functions and services along the west coast of North America, but populations have declined to the point of local extinction in some estuaries. Here, we present a species-level, range-wide approach to strategically planning the use of aquaculture to promote recovery of Olympia oysters. We identified 12 benefits of culturing Olympia oysters, including identifying climate-resilient phenotypes that add diversity to growers' portfolios. We also identified 11 key risks, including potential negative ecological and genetic consequences associated with the transfer of hatchery-raised oysters into wild populations. Informed by these trade-offs, we identified ten priority estuaries where aquaculture is most likely to benefit Olympia oyster recovery. The two highest scoring estuaries have isolated populations with extreme recruitment limitation-issues that can be addressed via aquaculture if hatchery capacity is expanded in priority areas. By integrating social criteria, we evaluated which project types would likely meet the goals of local stakeholders in each estuary. Community restoration was most broadly suited to the priority areas, with limited commercial aquaculture and no current community harvest of the species, although this is a future stakeholder goal. The framework we developed to evaluate aquaculture as a tool to support species recovery is transferable to other systems and species globally; we provide a guide to prioritizing local knowledge and developing recommendations for implementation by using transparent criteria. Our collaborative process engaging diverse stakeholders including managers, scientists, Indigenous Tribal representatives, and shellfish growers can be used elsewhere to seek win-win opportunities to expand conservation aquaculture where benefits are maximized for both people and imperiled species.

Despite the abundance of literature on organismal responses to multiple environmental stressors, most studies have not matched the timing of experimental manipulations with the temporal pattern of stressors in nature. We test the interactive effects of diel-cycling hypoxia with both warming and decreased salinities using ecologically realistic exposures. Surprisingly, we found no evidence of negative synergistic effects on Olympia oyster growth; rather, we found only additive and opposing effects of hypoxia (detrimental) and warming (beneficial). We suspect that diel-cycling provided a temporal refuge that allowed physiological compensation. We also tested for latent effects of warming and hypoxia to low-salinity tolerance using a seasonal delay between stressor events. However, we did not find a latent effect, rather a threshold survival response to low salinity that was independent of early life-history exposure to warming or hypoxia. The absence of synergism is likely the result of stressor treatments that mirror the natural timing of environmental stressors. We provide environmental context for laboratory experimental data by examining field time series environmental data from four North American west coast estuaries and find heterogeneous environmental signals that characterize each estuary, suggesting that the potential stressor exposure to oysters will drastically differ over moderate spatial scales. This heterogeneity implies that efforts to conserve and restore oysters will require an adaptive approach that incorporates knowledge of local conditions. We conclude that studies of multiple environmental stressors can be greatly improved by integrating ecologically realistic exposure and timing of stressors found in nature with organismal life-history traits.

Why does one native Olympia oyster restoration project succeed while a seemingly identical one fails? This project sought to answer the question by collecting recruitment, growth and survivorship statistics for oysters in Tomales Bay. Scientists also measured oyster predation by Atlantic oyster drills and are quantifying the effects of fouling organisms and “space competitors” (i.e., tunicates and sponges) on the availability of suitable oyster habitat. Findings are providing information on where and how to go about restoring oysters in California.

Global declines in foundation species and associated losses of biodiversity and ecosystem services have made restoration of foundation species and the habitats they create a top priority. Because restoration success has been highly variable, the field is increasingly using both experimentation and ecological theory to augment success. We conducted a meta‐analysis of studies (18) in estuarine and marine systems, which increased the abundance of top predators as a restoration approach, thus improving biogenic habitat‐forming foundation species recovery by reducing consumers. Beyond testing the general idea of whether top predator addition enhances foundation species restoration, we examined whether the degree of restoration success could be explained by classic predictors of top‐down strength, such as taxonomic identity of the foundation species and top predators, direct and indirect effects of top predators, and the latitude and duration of the study. Top predators successfully elicited a trophic cascade by decreasing consumer abundances (direct effect) and increasing foundation species recovery (indirect effect) when compared with control restoration projects without top predators. Direct effects are expected to be stronger than indirect effects, in accordance with classic ecological theory. We found no evidence of magnitude differences between direct and indirect effects of top predator addition. Increasing invertebrate top predators produced a 3.5× greater increase in the basal trophic level than adding vertebrate top predators. Despite the strong effect of predator type, the log response ratio of all foundation species types (algae, animal, and plant) increased 10‐fold in top predator addition treatments. We found diminishing effects of top predator addition as study duration increased, which supports recent developments that the positive effects of marine protected area designation decline over time. Our results highlight the promise of harnessing top‐down control via top predator addition as a mechanism to aid foundation species recovery. [ABSTRACT FROM AUTHOR]

In this descriptive case study, project-based learning is presented as a teaching model that combines elements from other learning strategies. High school students participating in an intertidal monitoring project built around this model increased their content knowledge related to the ecology of the intertidal zone and improved their scientific investigation skills. Several aspects of project-based instruction are considered critical to success. Projects grounded in authentic scientific research develop scientific investigation skills through real world application. Alignment of scientific and educational goals enhances learning when the project is conducted in a sound pedagogical manner while maintaining scientific authenticity. Student teamwork builds a scientific community and makes the work more manageable. One of the most critical elements for success is a long-term commitment to project activities with connections between the project and related curricular topics. Flexibility of the school curriculum enables required content to be connected to the project's thematic base. These connections provide students with a common knowledge foundation and make it easier for educators to build such projects into their curricula. (Contains 2 figures and 1 table.)

The study of "zonation", the distribution of plants and animals into distinct spatial areas, is a great way to introduce students to basic ecological concepts. Students can conduct methodical, quantifying surveys of zones in areas as diverse as mudflats, beaches, forests, wetlands, and fields. Students collect data from these areas with field ecology techniques such as transects and quadrats, which allow students to estimate how many different kinds of organisms exist in an area or to describe relative abundance. This article describes a lesson sequence in which students gain an understanding about quantitative sampling techniques and how to effectively evaluate which methods work best for different surveys or in different types of areas. The lesson sequence described in this article can be accomplished within one month as a standalone unit or incorporated into a larger unit of study in ecology. Providing students with an opportunity to conduct scientific work in a field setting is valuable, especially when the experience is connected to ongoing learning. Zonation mapping is an easy and powerful way for students to put their field experience into a larger scientific context, while also providing a concrete example of ecological concepts that is much more relevant to students than an abstract text example could ever be. (Contains 5 figures.)

More non-native species (NNS) are reported from harbors, estuaries and protected embayments than in wave-exposed, open-coast habitats. In California (USA), hundreds of NNS have become established in international ports, and dozens are known from smaller estuaries. In contrast, only 22 NNS are reported from the state's 1350 km of open coast. As a result, the perception that open-coast habitats are not vulnerable to invasions has persisted. Management and monitoring focuses on ports and estuaries; the last major monitoring effort on the open coast occurred in 2004. Much of the species-rich Central California coast is now part of a network of marine protected areas (MPAs). We surveyed 12 wave-swept rocky intertidal and eight subtidal sites (from 37°53'40N 122°42'30W to 36°31'16N 121°56'22W) for NNS. At least one NNS was detected at half of the sites surveyed, but most were not widespread or abundant. One exception, a bryozoan in the Watersipora spp. complex, known primarily from ports and estuaries, was found at multiple sites, and was abundant at some. Another non-native, the alga Caulacanthus ustulatus, was abundant at a single site. MPAs were just as likely as sites outside of MPAs to have NNS. For subtidal sites, proximity to a harbor was correlated with the abundance of non-natives. Our findings suggest that our study area is still relatively uninvaded, but the success of Watersipora within some of these highly diverse rocky shore sites underscores the potential vulnerability of high-value open-coast systems to invasions., Author(s): Chela J. Zabin [sup.1] , Michelle Marraffini [sup.1] , Steve I. Lonhart [sup.2] , Linda McCann [sup.1] , Lina Ceballos [sup.1] , Chad King [sup.2] , James Watanabe [sup.3] [...]

Thirteen benthic rocky intertidal communities were quantitatively assessed on Maui, Moloka'i, O'ahu, and Hawai'i Island between the years 2004 and 2007. Our goals were to test for differences in invertebrate and macroalgal abundance and composition to understand how these tropical communities are organized. Percentage cover surveys revealed a diverse intertidal system with 49 macroalgal, 1 cyanobacterial, and 31 invertebrate taxa. Shores were frequently dominated by a few macroalgae and mollusks, and at two sites these organisms were distributed in discrete vertical bands. Common intertidal taxa included the introduced alga Acanthophora spicifera; species in the macroalgal genera Padina, Sargassum, and Laurencia; turf forms of algae; and the mollusks Siphonaria normalis, Nerita picea, and species of littorine snails. Multivariate statistics found community structure to vary among sites and years, but there was lack of evidence for island-specific or substratum-specific assemblages. SIMPROF analysis revealed support for 11 different types of structure. This first description of community-level patterns at multiple intertidal sites along the Main Hawaiian Islands documents substantial spatial variation both among and within shores, as well as substantial temporal variation for select sites. These findings are in contrast to the characterization of a homogeneous tropical system and thus suggest that biotic and abiotic factors in the Main Hawaiian Islands act on a local scale to drive structure., SYSTEMATIC MONITORING of ecological communities provides a baseline from which to measure human impacts in the long term (Murray et al. 2006) and in the short term allows for early [...]

ABSTRACT Oyster shell may be taken from one bay and placed in another for a variety of purposes, including the restoration or enhancement of native oysters or other native species. [...]

International and national guidelines and regulations to limit the inadvertent transfer of non-native species on the submerged surfaces of vessels and mobile infrastructure are progressing. However, methods to assess compliance must be developed to assist both regulators and industry. While there is a history of biofouling inspections in maritime industries, including commercial shipping and infrastructure, such surveys are tailored for vessel safety and performance rather than being driven by biosecurity purposes. Thus, these inspections are likely inadequate for confirming compliance with biosecurity regulations. To determine regulatory compliance, agencies will likely rely on a combination of risk profiling, assessment of documentation of biofouling management, archival data and images, and real-time in-water surveys made by divers or remotely operated vehicles (ROVs) specific to biosecurity regulations. Divers may exceed ROVs at finding organisms in recesses and other topographically complex areas, and when regulations require confirmation of species identity or viability. In contrast, ROVs may be well suited for regulations that establish upper thresholds on biofouling levels with little concern for organism identity or condition. Several factors will inform how a survey is conducted, including cost, the type of data required by regulations, environmental conditions, safety, and logistics. Survey designs and requirements should be transparent to manage industry's expectations of border procedures, to increase the efficiency with which industry and agencies manage biofouling and potentially align the evaluation of best practices in hull and niche area maintenance across jurisdictions. [ABSTRACT FROM AUTHOR]

Invasive species remain a major environmental problem in the world's oceans. Managing the vectors of introduction is the most effective means of mitigating this problem, but current risk assessments and management strategies are largely focused on species, not on vectors and certainly not on multiple simultaneous vectors. To highlight the issue that multiple vectors contribute to invasions, we analyzed the historical and contemporary contributions of eight maritime vectors to the establishment of nonindigenous species in California, where most species were associated with two to six vectors. Vessel biofouling looms larger than ballast water as a major vector and a management opportunity, but aquaculture risk appears reduced from historic levels. Standardized data on species abundances in each vector are lacking for a robust cross-vector assessment, which could be obtained in a proof-of-concept "vector blitz." Management must shift away from one or two target vectors to coordination across multiple vectors. [ABSTRACT FROM AUTHOR]

The intertidal zone of tropical islands is particularly poorly known. In contrast, temperate locations such as California's Monterey Bay are fairly well studied. However, even in these locations, studies have tended to focus on a few species or locations. Here we present the results of the first broadscale surveys of invertebrate, fish and algal species richness from a tropical island, Oahu, Hawaii, and a temperate mainland coast, Central California. Data were gathered through surveys of 10 sites in the early 1970s and again in the mid-1990s in San Mateo and Santa Cruz counties, California, and of nine sites in 2001-2005 on Oahu. Surveys were conducted in a similar manner allowing for a comparison between Oahu and Central California and, for California, a comparison between time periods 24 years apart. We report a previously undocumented richness of intertidal species in both locations: 516 for Oahu and 801 for Central California. Surprisingly, when differences in search efforts are controlled, overall (alpha) diversity appears to be similar between locations, although site level (beta) diversity is much higher in California. Species richness in California generally increased along a wave exposure gradient and distance from an urban area. Much higher numbers of both invasive and endemic species were found on Oahu. In California, more invertebrate species were found in the 1990s, likely due to an improvement in taxonomic resources since the 1970s, and species composition was different in the two surveys due to the high incidence of rare species. Although some southern species increased in number between the two time periods and some northern species decreased, we detected little evidence of change favoring southern or northern species. These results are in line with recent findings that water temperatures in the Monterey Bay have been in a cooling trend since the 1980s, in contrast to many locations elsewhere in the world. [ABSTRACT FROM AUTHOR]

Thirteen benthic rocky intertidal communities were quantitatively assessed on Maui, Moloka'i, O'ahu, and Hawai'i Island between the years 2004 and 2007. Our goals were to test for differences in invertebrate and macroalgal abundance and composition to understand how these tropical communities are organized. Percentage cover surveys revealed a diverse intertidal system with 49 macroalgal, 1 cyanobacterial, and 31 invertebrate taxa. Shores were frequently dominated by a few macroalgae and mollusks, and at two sites these organisms were distributed in discrete vertical bands. Common intertidal taxa included the introduced alga Acanthophora spicifera; species in the macroalgal genera Padina, Sargassum, and Laurencia; turf forms of algae; and the mollusks Siphonaria normalis, Nerita picea, and species of littorine snails. Multivariate statistics found community structure to vary among sites and years, but there was lack of evidence for island-specific or substratum-specific assemblages. SIMPROF analysis revealed support for 11 different types of structure. This first description of community-level patterns at multiple intertidal sites along the Main Hawaiian Islands documents substantial spatial variation both among and within shores, as well as substantial temporal variation for select sites. These findings are in contrast to the characterization of a homogeneous tropical system and thus suggest that biotic and abiotic factors in the Main Hawaiian Islands act on a local scale to drive structure. [ABSTRACT FROM AUTHOR]