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Stock-recruitment relationships for managing commercial fisheries are difficult to measure and notoriously poor, so marine ecologists have relied on larval recruitment as a proxy for how planktonic processes regulate populations and communities. However, my literature review revealed that coupling between reproductive output and recruitment in benthic populations was common, occurring in 62% of 112 studies and 64% of 81 species. Coupling was considerably stronger for studies on brooders (72%) than broadcast-spawners (46%) and taxa with short (74%) than long (56%) planktonic larval durations (PLDs); hence, it was highest for brooders with short PLDs (94%). Coupling was similar in studies on benthic animals (63%) and seagrasses and kelp (56%). Coupling was detected more often by quantifying both reproductive output and settlement (79%) than adult density and recruitment (60%). It also was detected in 83% of just 21% of studies that estimated dispersal. Coupling was even detected by 55% of the 46% of studies conducted at just one site and 58% of the 65% of studies lasting no longer than 3 years. Decoupling was detected 33 times in invertebrates and fishes, occurring more often in the plankton (48.5%) and during reproduction (45.5%) than after settlement (6%), and nine times in seagrasses and kelp, occurring more often during reproduction (44.4%) than postsettlement (33.3%) or in the plankton (22.2%). Widespread coupling between reproductive output and settlement for sedentary, benthic species suggests that the poor stock-recruitment relationships typical of vagile, wide-ranging, pelagic species may be due more to the difficulty of detecting them than decoupling.

Larval dispersal phases are a key determinant of population dynamics in recruitment-limited, coastal upwelling regions. Larvae were long considered to be highly susceptible to offshore transport, except in the lee of headlands where eddies form during upwelling conditions. We examined the spatial variation of benthic invertebrate larval assemblages in relation to the retentive upwelling shadow in northern Monterey Bay (California, USA) during strong upwelling (August 2013) and weak upwelling (October 2013). We characterized the spatial variation in physical characteristics of the water column, determined the cross-shore and depth distributions of invertebrate larvae in relation to the upwelling shadow, and examined how these physical and biological patterns change with upwelling strength. Larval abundances and environmental data (water temperature, salinity, chlorophyll a concentration) were collected simultaneously using a plankton pump and profiling CTD at 3 depths: above, within, and below the chlorophyll a maximum layer. Larvae were primarily detected near the bottom. Larvae of most taxa were positively associated with a subsurface chlorophyll a maximum layer in August, but not in October when this layer was near the surface. Adult habitat distribution was related to the spatial distribution of larvae. Larvae of nearshore taxa occurred in the inner bay, while larvae of predominately offshore taxa occurred in the outer bay. Taxa with similar adult habitat (nearshore versus offshore) co-occurred in water samples. In addition, larvae of offshore taxa were commonly associated with offshore water types. Thus, the distribution of larvae within northern Monterey Bay appears to be strongly influenced by adult habitat distribution, vertical positioning of larvae in the water column, and upwelling strength.

Marine Protected Areas (MPAs) are increasingly established globally as a spatial management tool to aid in conservation and fisheries management objectives. Assessing whether MPAs are having the desired effects on populations requires effective monitoring programs. A cornerstone of an effective monitoring program is an assessment of the statistical power of sampling designs to detect changes when they occur. We present a novel approach to power assessment that combines spatial point process models, integral projection models (IPMs) and sampling simulations to assess the power of different sample designs across a network of MPAs. We focus on the use of remotely operated vehicle (ROV) video cameras as the sampling method, though the results could be extended to other sampling methods. We use empirical data from baseline surveys of an example indicator fish species across three MPAs in California, USA as a case study. Spatial models simulated time series of spatial distributions across sites that accounted for the effects of environmental covariates, while IPMs simulated expected trends over time in abundances and sizes of fish. We tested the power of different levels of sampling effort (i.e., the number of 500-m ROV transects) and temporal replication (every 1-3 yr) to detect expected post-MPA changes in fish abundance and biomass. We found that changes in biomass are detectable earlier than changes in abundance. We also found that detectability of MPA effects was higher in sites with higher initial densities. Increasing the sampling effort had a greater effect than increasing sampling frequency on the time taken to achieve high power. High power was best achieved by combining data from multiple sites. Our approach provides a powerful tool to explore the interaction between sampling effort, spatial distributions, population dynamics, and metrics for detecting change in previously fished populations.

Evolutionary responses to opposing directions of natural selection include trade-offs, where the phenotype balances selective forces, and compensation, where other traits reduce the impact of one selective force. Zooplankton pigmentation protects from ultraviolet radiation (UVR) but attracts visual predators. This trade-off is understudied in the ocean where planktonic larvae in surface waters face ubiquitous UVR and visual predation threats. We tested whether crab larvae can behaviorally reduce UVR risk through downward swimming or expansion of photoprotective chromatophores. Then we examined whether more pigmented larvae are more heavily predated by silverside fish under natural sunlight in the tropics in three UVR treatments (visible light, visible + UVA, visible + UVA + UVB). Lastly, we tested the behavioral chromatophore response of larvae to predation threats in two light treatments. Armases ricordi avoided surface waters after exposure to sunlight with UVR. Armases ricordi, Armases americanum, and Eurypanopeus sp. consistently expanded chromatophores in UVR or visible light, while Mithraculus sculptus and Mithraculus coryphe showed no response. Fish preferred pigmented larvae on sunnier days in visible light lacking UVR. Lastly, both M. coryphe and M. sculptus unexpectedly expanded chromatophores in fish cues, but responses were inconsistent over trials and across light treatments. The more consistent larval responses to UVR than to predator cues and the lack of predator preferences in natural light conditions suggest that UVR may have a stronger influence on pigmentation than predation. This study improves our understanding of planktonic adaptation to countervailing selection caused by visual predation and exposure to UVR.

Understanding sources of variability in larval supply and transport is integral to the dynamics, structure and effective management of marine populations and communities. Yet, a barrier to this understanding is the high variability in the supply and transport of marine larvae, especially in upwelling regions where wind forcing causes dynamic circulation. Since larvae of many species complete development close to shore, resolving the relationship between oceanographic processes and nearshore larval assemblages is essential to better understand larval transport in highly productive upwelling regions. The goal of our study was to examine the effects of variation in upwelling and relaxation dynamics on the nearshore larval assemblage in northern Monterey Bay. To determine how seasonal and daily upwelling and relaxation dynamics influence the nearshore larval assemblage, we surveyed distributions of marine larvae and physical, environmental factors along a cross-shelf transect in northern Monterey Bay, USA, during August and October of 2013. Conditions in August and October differed in temperature, salinity, stratification, and chlorophyll-a fluorescence. Richness and diversity of the larval assemblage did not change appreciably, but the abundance and composition of species shifted after the influx of offshore waters. Specifically, nearshore taxa were more abundant during August, which was characterized by strong upwelling conditions, and especially more abundant with increased wind forcing leading to a retentive upwelling shadow in the northern bay. Conversely, offshore taxa were more abundant during October, which was characterized by weakened upwelling and the persistent influx of offshore water. Our study suggests that relationships between larval taxa, life history characteristics, and water types provide insights into water mass history, circulation and larval recruitment in highly dynamic upwelling regions.

Dispersal of benthic species in the sea is mediated primarily through small, vulnerable larvae that must survive minutes to months as members of the plankton community while being transported by strong, dynamic currents. As climate change alters ocean conditions, the dispersal of these larvae will be affected, with pervasive ecological and evolutionary consequences. We review the impacts of oceanic changes on larval transport, physiology, and behavior. We then discuss the implications for population connectivity and recruitment and evaluate life history strategies that will affect susceptibility to the effects of climate change on their dispersal patterns, with implications for understanding selective regimes in a future ocean. We find that physical oceanographic changes will impact dispersal by transporting larvae in different directions or inhibiting their movements while changing environmental factors, such as temperature, pH, salinity, oxygen, ultraviolet radiation, and turbidity, will affect the survival of larvae and alter their behavior. Reduced dispersal distance may make local adaptation more likely in well-connected populations with high genetic variation while reduced dispersal success will lower recruitment with implications for fishery stocks. Increased dispersal may spur adaptation by increasing genetic diversity among previously disconnected populations as well as increasing the likelihood of range expansions. We hypothesize that species with planktotrophic (feeding), calcifying, or weakly swimming larvae with specialized adult habitats will be most affected by climate change. We also propose that the adaptive value of retentive larval behaviors may decrease where transport trajectories follow changing climate envelopes and increase where transport trajectories drive larvae toward increasingly unsuitable conditions. Our holistic framework, combined with knowledge of regional ocean conditions and larval traits, can be used to produce powerful predictions of expected impacts on larval dispersal as well as the consequences for connectivity, range expansion, or recruitment. Based on our findings, we recommend that future studies take a holistic view of dispersal incorporating biological and oceanographic impacts of climate change rather than solely focusing on oceanography or physiology. Genetic and paleontological techniques can be used to examine evolutionary impacts of altered dispersal in a future ocean, while museum collections and expedition records can inform modern-day range shifts.

Morphological defences of plankton can include armour, spines and coloration. Spines defend from gape-limited fish predators, while pigmentation increases visibility to fishes but defends from ultraviolet radiation (UVR). Planktonic crab larvae (zoeae) exhibit inter- and intraspecific variability in the lengths of defensive spines, extent of pigmentation and body size. The determinants of this variability and the relationships among these traits are largely unknown. Larvae may employ generalized defences against the dual threats of UVR and predation or specialized defences against their primary threat, with an unknown role of allometric or phylogenetic constraints. Generalization would result in longer spines compensating for the increased predation risk imposed by darker pigments, while specialization would lead to more investment in either defence from predation (long spines) or UVR (dark pigments), at the expense of the other trait. We examined (a) the relationship between spine lengths and pigmentation, (b) the scaling of spine lengths with body size, and (c) phylogenetic constraint in spine lengths, pigmentation, and body size, among and within 21 species of laboratory-hatched and 23 species of field-collected crab larvae from Panama and California. We found a negative relationship between spine length and pigmentation among species from laboratory and field. Within species, we found a marginally significant negative relationship among field-collected larvae. Spine lengths showed positive allometric scaling with carapace length, while spine and carapace lengths, but not pigmentation, had significant phylogenetic signals. The negative relationship we observed between pigmentation and spine length supports our defence specialization hypothesis. Positive allometric scaling of spine lengths means larger larvae are better defended from predators, which may indicate that larvae face greater predation risk as they grow larger. Phylogenetic constraint may have arisen because related species encounter similar predation threats. Conversely, phylogenetic constraint in the evolution of spine lengths may induce convergent behaviours resulting in related species facing similar predation threats. Our results improve understanding of the evolution of the larval morphology of crabs, morphological defences in the plankton and evolutionary responses of morphology to multiple spatially segregated selective forces. A free Plain Language Summary can be found within the Supporting Information of this article.

Surfzone mixing and transport on a sandy, steep (∼1/8 slope), reflective beach at Carmel River State Beach, California, are described for a range of wave and alongshore flow conditions. Depth-limited wave breaking occurred close to the shore due to the steepness of the beach, creating a narrow surf/swash zone (∼10 m wide). Fluorescent Rhodamine dye was released as a slug in the surfzone, and the temporal and spatial evolution was measured using in-situ dye sensors. Dye concentration measured as a function of time reveals sharp fronts that quickly decay resulting in narrow peaks near the dye release, which subsequently broaden and decrease in peak concentration with alongshore distance. The measurements indicate two stages of mixing and transport occur inside the surfzone on the steep beach. 1) In the near-field (50 m downstream from the dye release location), the mass transport was dominated by advection. The distance to the far-field is much shorter in the alongshore on a steep beach compared with a dissipative beach. Estimates of cross-shore and alongshore diffusion coefficients (κ x , κ y ) were found to be similar in magnitude within the surfzone. Outside the surfzone in the far-field, the results suggest that the mixing processes are independent of those inside the surfzone. The mixing and transport of material observed on this steep beach are found to be analogous to that previously measured on dissipative beaches, however the diffusion coefficients within and outside the surfzone were found to be smaller on this steep beach.

Plankton live under the countervailing selective pressures of predation and ultraviolet radiation (UVR). In lakes, zooplankton are transparent reducing visibility to predatory fishes but are pigmented in the absence of fishes, hypothetically reducing UVR damage. In the sea, planktivorous fishes are widespread, so plankton typically are transparent and ascend to productive surface waters at night to forage and descend during the day to reduce visibility to predators. However, larvae of some species face the unique constraint of traveling in surface currents in the daytime during migrations between adult and larval habitats. We would expect these larvae to be transparent since companion studies demonstrated increased predation risk of pigmented larvae under strong sunlight. Paradoxically, larvae range from being darkly to lightly pigmented. We hypothesize that some larvae are more heavily pigmented to reduce UVR damage, while other species travelling in subsurface currents with low UVR might be more transparent. Linking larval morphology to depth-dependent selective pressures would add a key element to help improve predictions of larval vertical distributions, which are important for simulating larval transport trajectories. We quantitatively tested the hypothesis that selection may have favored photoprotective pigmentation for larvae in the predominantly transparent plankton community while testing the differential effects of UVA and UVB radiation. We measured larval pigmentation of 12 species of crabs and exposed them to visible light only, visible + UVA, or visible + UVA + UVB in the tropics. Controlling for phylogeny, more pigmented species survived UVR better than less pigmented species, especially on sunnier days, though intraspecific comparisons for four species were equivocal. Most species died even from UVA exposure, which has long been regarded as relatively harmless despite penetrating deeper underwater than UVB. Thus, we demonstrate with a phylogenetically controlled analysis that crab larvae are pigmented in the predominantly transparent planktonic community to protect from UVR, improving our understanding of the selective forces acting on animal coloration and the factors determining planktonic distributions, survival, and dispersal. This linkage of morphology with susceptibility will be important for developing mechanistic models of environmental stress responses to better predict larval dispersal in current and future climates.

We demonstrate an apparent trait-mediated indirect interaction (TMII) of predators on primary producers in a natural community by altering prey behavior over short and long time scales. Small predatory sea stars (Leptasterias spp.) caused herbivorous snails (Tegula funebralis) added to rocky intertidal tidepools to quickly flee into refuge microhabitats outside tidepools within days, and this was associated with a 58% increase in microalgal growth after 2 weeks. Similarly, removing sea stars caused snails to increase use of tidepools for 1–10 months. After adding sea stars to tidepools, snails quickly fled and then consistently increased use of refuges outside tidepools for 10 months. This was associated with average increases of 59% for microalgal growth over 1 month and 254% for macroalgal growth over 8 months inside tidepools. In 63 unmanipulated tidepools, densities of sea stars and snails were negatively correlated. High densities of snails were associated with unpalatable algal species and bare rock, while high densities of sea stars were associated with palatable algal species, suggesting that this apparent TMII may have community-level impacts. Though multiple lines of evidence suggest TMIIs were likely operating in this system, it was not possible to experimentally partition the relative contributions of TMIIs and density-mediated indirect interactions (DMIIs), so further caging experiments are necessary to distinguish their relative strengths. Overall, we suggest that predators can benefit primary producers by changing prey behavior even when predators and prey are unrestrained by cages or mesocosms, embedded in complex communities, and observed over multiple time scales.

Larval transport by marine organisms is regulated by a combination of vertical swimming behavior and seasonal reproductive timing, but recent studies suggest horizontal swimming behaviors may also be important. Larvae in highly productive coastal upwelling regions are especially vulnerable to offshore transport and must employ effective dispersal “strategies” to return onshore to suitable settlement sites. Using a primitive-equation numerical model, we investigate how horizontal swimming affects nearshore larval supply and potential settlement and connectivity during climatological spring and summer in central California, a region of persistent coastal upwelling within the California Current System. The addition of shoreward swimming with speeds of 1–7 cm s−1 increases nearshore larval supply by a factor of 1.4–13, depending on the speed, timing of its onset, and the vertical swimming behavior of the larvae, which included both diel and ontogenetic vertical migrations. Nearshore larval supply increases approximately linearly with swimming speed integrated over the pelagic larval duration. While pelagic connectivity increases with shoreward swimming for all vertical behaviors investigated, spatial patterns of connectivity, when standardized by nearshore larval supply, are similar with and without horizontal behavior. Onshore swimming broadens the alongshore extent of areas that can act as effective source regions in central California, increasing potential dispersal distances 11–26%. A related statistic, the reverse pelagic connectivity, reveals Monterey Bay and the Gulf of the Farallones as important source regions that should be considered when adaptively managing California's network of marine protected areas.

The Intermittent Upwelling Hypothesis (IUH) posits that subsidies of larvae and phytoplankton to intertidal communities should vary unimodally along a gradient of upwelling from persistent upwelling to persistent downwelling with most subsidies occurring where upwelling is of intermediate strength and intermittent. Furthermore, the hypothesis states that larvae and phytoplankton are transported far offshore by strong, persistent upwelling and fail to subsidize nearshore communities, whereas weak upwelling or downwelling reduces nutrients for phytoplankton production limiting food for larvae and nearshore communities. We review studies conducted at sea and onshore and reanalyze published data to test the IUH and evaluate alternative hypotheses. To test the hypothesis, we examine five predictions that must hold if the IUH is true. (1) Larvae should inhabit the surface Ekman layer where they are transported offshore during upwelling. Larvae of many intertidal taxa occur deeper in the water column where currents flow shoreward during upwelling. (2) Larvae of nearshore species should occur farther offshore during upwelling than during relaxation or downwelling. Larvae of many nearshore species remain within several kilometers of shore during both conditions. (3) Larval settlement in intertidal communities should be lower during upwelling than relaxation or downwelling. Daily larval settlement has not observed to be higher during relaxation or downwelling events; settlement has most often been seen to vary with the fortnightly tidal cycle likely due to onshore larval transport by internal tides. (4) Larval settlement and recruitment in intertidal communities should be lower in areas of strong, persistent upwelling than where upwelling is weaker and less persistent. Recruitment of mussels and barnacles to artificial and natural substrates did not vary with the strength of upwelling, but did vary inversely with two measures of desiccation potential, and directly with indicators of surf zone hydrodynamics; larval recruitment was higher where surf zones were more dissipative with rip currents. (5) Phytoplankton subsidies to nearshore communities should be highest where upwelling is moderate and intermittent. Like larval subsidies, phytoplankton subsidies varied spatially with surf zone hydrodynamics rather than upwelling. This reconsideration of the evidence for the IUH finds the hypothesis unsupported.

Understanding the conditions that drive variation in recruitment of key estuarine species can be important for effective conservation and management of their populations. The Olympia oyster (Ostrea lurida) is native to the Pacific coast of North America and has been a target of conservation efforts, though relatively little information on larval recruitment exists across much of its range. This study examined the recruitment of Olympia oysters at biweekly to monthly intervals at four sites in northern San Francisco Bay from 2010 to 2015 (except 2013). Mean monthly temperatures warmed at all sites during the study, while winter (January–April) mean monthly salinity decreased significantly during a wet year (2011), but otherwise remained high as a result of a drought. A recurring peak in oyster recruitment was identified in mid-estuary, in conditions corresponding to a salinity range of 25–30 and >16 °C at the time of settlement (April–November). Higher average salinities and temperatures were positively correlated with greater peak recruitment. Interannual variation in the timing of favorable conditions for recruitment at each site appears to explain geographic and temporal variation in recruitment onset. Higher winter/spring salinities and warmer temperatures at the time of recruitment corresponded with earlier recruitment onset within individual sites. Across all sites, higher winter/spring salinities were also correlated with earlier onset and earlier peak recruitment. Lower winter salinities during 2011 also resulted in a downstream shift in the location of peak recruitment.

Surf zones, regions of breaking waves, are at the interface between the shore and coastal ocean. Surf zone hydrodynamics may affect delivery of phytoplankton subsidies to the intertidal zone. Over a month of daily sampling at an intermediate surf zone with bathymetric rip currents and a reflective surf zone, we measured surf zone hydrodynamics and compared concentrations of coastal phytoplankton taxa in the surf zones to concentrations offshore. At the intermediate surf zone, ~80% of the variability in the concentration of coastal phytoplankton taxa within the surf zone was explained by their variation offshore; however, concentrations were much higher and lower than those offshore in samples from a bathymetric rip current and over the adjacent shoal, respectively. Hydrodynamics at this intermediate surf zone did not hinder the delivery of coastal phytoplankton to the surf zone, but the bathymetric rip current system appeared to redistribute phytoplankton concentrating them within eddies. At the reflective shore, we sampled surf zones at a beach and two adjacent rocky intertidal sites. Concentrations of typical coastal phytoplankton taxa were usually an order of magnitude or more lower than those offshore, even when offshore samples were collected just 20 m beyond the breakers. The phytoplankton assemblages inside and outside the surf zone often appeared to be disconnected. Surf zone hydrodynamics at the steep, reflective shore coupled with low phytoplankton concentrations in near-surface water appeared to limit delivery of phytoplankton subsidies to the surf zone. Surf zone hydrodynamics may be a key factor in the alongshore variation in phytoplankton subsidies to coastal communities.

Planktonic larvae are thought to be very susceptible to offshore advection in upwelling regimes, increasing dispersal and decreasing recruitment. However, larvae of 42 species of nearshore benthic crustaceans primarily developed on the inner shelf at locations both in (98.5%) and away (99.8%) from a perennial upwelling center in the upwelling season of a recruitment-limited region characterized by persistent, strong, upwelling. During three cross-shelf cruises conducted at each location, larvae of 21 species remained on the inner shelf at both sites by occurring beneath seaward-flowing surface currents while larvae of other species migrated to midshelf (four species) or offshore (14 species) by initially developing near the surface. Postlarvae apparently returned to shore either deep in landward-flowing upwelled water or near the surface where behavior allows them to be transported shoreward by internal waves, diel wind cycles or wind relaxation events. Thus, recruitment limitation in upwelling regimes does not appear to be caused by larval mortality from offshore transport, requiring new research directions to advance our understanding of population dynamics, structure and connectivity.

We investigated whether cross-shore distributions of coastal phytoplankton to the surf zone are controlled by hydrodynamics and their biological characteristics. Data from a rip-channeled beach indicate that concentrations of phytoplankton are higher in the surf zone than offshore. To examine how phytoplankton is transported toward the shore, we used a coupled biophysical model, comprised of a 3D physical model of coastal dynamics and an individual-based model (IBM) for tracking phytoplankton on the rip-channeled beach. Waves and wind in the biophysical model were parameterized by the conditions during the sampling period. Previous studies indicated that growth rates of phytoplankton can be enhanced by high turbulence, which might contribute to high phytoplankton concentration in the surf zone. Some numerical and laboratory works showed that turbulence can also increase the downward velocity of phytoplankton, which could be carried by onshore bottom currents and remain in the surf zone. Furthermore, we adapted the IBM with the theoretical model of diurnal vertical migration (DVM) for phytoplankton. The theoretical DVM works as follows: in the morning, phytoplankton cells adhere to air bubbles and stay at the surface and close to the shore in the daytime because onshore wind and surface current direction is usually onshore; in the late afternoon, the cells switch their attachment from air bubbles to sand grains and sink to the bottom where the water flow is normally onshore at night. Finally, depth-varying growth of phytoplankton was also incorporated into the DVM module. Simulations using neutral passive particles do not give the expected results of observed patterns. All tested mechanisms, i.e., wind- and wave-driven currents, rip-current circulation, turbulence-driven growth and sinking, DVM, and depth-varying growth, enhanced onshore phytoplankton migration and cell concentrations in the surf zone, indicating that both biological traits and physical factors can be essential to phytoplankton cross-shore transport and spatial variability. Our model is open to be modified and re-parameterized, followed by further analysis and validation, so that it can be more adequate for ecological assessment of coastal areas.

Plankton are transported onshore, providing subsidies of food and new recruits to surf-zone and intertidal communities. The transport of plankton to the surf zone is influenced by wind, wave, and tidal forcing, and whether they enter the surf zone depends on alongshore variation in surf-zone hydrodynamics caused by the interaction of breaking waves with coastal morphology. Areas with gently sloping shores and wide surf zones typically have orders-of-magnitude-higher concentrations of plankton in the surf zone and dense larval settlement in intertidal communities because of the presence of bathymetric rip currents, which are absent in areas with steep shores and narrow surf zones. These striking differences in subsidies have profound consequences; areas with greater subsidies support more productive surf-zone communities and possibly more productive rocky intertidal communities. Recognition of the importance of spatial subsidies for rocky community dynamics has recently advanced ecological theory, and incorporating surf-zone hydrodynamics would be an especially fruitful line of investigation.

Surf zone hydrodynamics vary along shorelines potentially affecting the delivery of larvae and zooplankton subsidies to intertidal communities, and, hence, the intensity of postsettlement interactions, growth and reproduction of filter-feeding foundation species and planktivorous fishes. We investigated the ability of zooplankton assemblages to enter the wide surf zone of the rip-channeled, more dissipative beach at Sand City, California, and the narrow surf zone of the steep reflective beach at nearby Carmel River State Beach. Every day for a month, we surveyed zooplankton inside and outside the surf zone and concomitant larval settlement of the dominant invertebrate onshore at each site in this upwelling regime. At the more dissipative surf zone, all zooplankters were far more concentrated inside than outside the surf zone. Many taxa increased in the surf zone and the predominant invertebrate on beaches, Emerita analoga, settled abundantly when prevailing northwesterly winds relaxed and waves were small. At the reflective surf zone, concentrations of zooplankters of most taxa were far greater outside than inside the surf zone, and many taxa increased in the surf zone when waves were small. Twice as many taxa were positively correlated inside and outside the surf zone at the dissipative than the reflective surf zone, indicating that zooplankters were more freely exchanged although behavior also played a role. Thus, spatial and temporal variation in surf zone hydrodynamics may regulate subsidies of zooplankton food and larval recruits to nearshore communities with potential cascading effects on community dynamics and structure.

Larvae in the coastal ocean are transported toward shore by a variety of mechanisms. Crossing the surf zone is the last step in a shoreward migration and surf zones may act as semipermeable barriers altering delivery of larvae to the shore. We related variation in the structure of intertidal barnacle populations to surf zone width (surf zone hydrodynamics proxy), wave height, alongshore wind stress (upwelling proxy), solar radiation, and latitude at 40 rocky intertidal sites from San Diego, California to the Olympic Peninsula, Washington. We measured daily settlement and weekly recruitment of barnacles at selected sites and related these measures to surf zone width. Chthamalus density varied inversely with that of Balanus, and the density of Balanus and new recruits was negatively related to solar radiation. Across the region, long-term mean wave height and an indicator of upwelling intensity and frequency did not explain variation in Balanus or new recruit densities. Balanus and new recruit densities, daily settlement, and weekly recruitment were up to three orders of magnitude higher at sites with wide (>50 m), more dissipative surf zones with bathymetric rip currents than at sites with narrow (

Nearly all of our understanding of rocky inter-tidal ecology comes from studies conducted at low tide. To study inter-tidal organisms at high tide, we anchored waterproof digital GoPro® video cameras in wave-exposed tidepools and recorded the daytime movements of the black turban snail, Tegula funebralis, over the tidal cycle between May and August 2012 near Bodega Bay, California. Overall, snails moved more quickly and presumably foraged more during low tides and on days with warmer air and perhaps water temperatures. This is similar to other ectotherms that exhibit increased metabolic rates, movement and foraging in warmer conditions. Snails also moved less during flood and high tides, may have moved downward in tidepools at flood tides, and showed evidence of reduced activity on days with larger waves. This inactivity and refuge seeking may have been a strategy to avoid dislodgment by waves. Analysis of snail trajectories showed foraging bouts indicated by alternating zig-zagging and straight movement. There was no effect of temperature, wave height, or tidal phase on distribution of snail turning angles, suggesting that they may have foraged consistently but moved faster during warm conditions and low tides, thereby grazing a larger area. This is one of few direct recordings of inter-tidal organisms on wave-exposed rocky shores during high tide. The methods used here are easily transferable to other studies, which are needed to increase our understanding of behaviors that structure rocky shore communities during high tide.

Recent mass mortalities of two predatory sea star species provided an unprecedented opportunity to test the effect of predators on rocky intertidal prey. Mass mortalities provide insight that manipulative experiments cannot because they alter ecosystems on a larger scale, for longer time periods, and remove both organisms and their cues from the environment. We examined shifts in population size structure, vertical zonation, and use of emersed refuge habitats outside tidepools by the abundant herbivorous black turban snail Tegula funebralis, both before and after the successive mortalities of two predatory sea stars. The small cryptic predator Leptasterias spp. suffered a localized but extreme mortality event in November 2010, followed by two mass mortalities of the keystone predator Pisaster ochraceus in August 2011 and autumn 2013. After the local extinction of Leptasterias, the population size of Tegula more than doubled. Also, since Leptasterias primarily inhabited only mid to low intertidal tidepools at this site, small and medium sized snails (which are preferred by Leptasterias) shifted lower in the intertidal and into tidepools after the mortality of Leptasterias. After the mortality of Pisaster in August 2011, large snails did not shift lower in the intertidal zone despite being preferred by Pisaster. Small and medium sized snails became denser in the higher zone and outside tidepools, which was not likely due to Pisaster mortality. Previous studies concluded that Pisaster maintained vertical size gradients of snails, but our data implicate the overlooked predator Leptasterias as the primary cause. This natural experiment indicated that (1) predators exert top-down control over prey population sizes and lower limits, (2) vertical zonation of prey are dynamic and controlled in part by prey behavior, and (3) predators exert the strongest effects on more vulnerable individuals, which typically inhabit stressful habitats higher on the shore or outside tidepools to avoid predation. Because the mass mortalities of two predators drastically reduced both the predation pressure and the chemical cues of predators in the environment, we were able to investigate both the effects of predators on prey populations and the effects on mobile prey behavior.

Recruitment of marine fishes is largely determined by biological and environmental factors acting on early-life stages. Subtle changes in larval condition in response to their environment can result in order-of-magnitude differences in year-class-strength. Overlap of larval production and favorable feeding conditions drives recruitment for many temperate marine fishes, but challenges associated with studying marine larvae have made it difficult to assess how environmental processes act on individual larvae to affect their growth and survival. We conducted a 2-yr study in an upwelling system to assess the influence of regional productivity, temperature, and larval condition in explaining growth in rockfishes (Sebastes spp.). We employed otolith microstructure and satellite imagery to measure initial larval growth and estimate the productivity and temperature experienced by individuals to determine their relative importance in subsequent growth at metamorphosis. We compared model performance using indexed environmental conditions scaled over three different regions. In both years, net primary productivity explained the most variation in pre-metamorphic growth relative to temperature and initial growth. This relationship was consistent across spatial regions, although model fit was highest using indices scaled to the south continental shelf region. Recent settlement, juvenile recruitment, and individual growth were significantly higher in a year when productivity bloomed earlier and individual larvae experienced higher levels of productivity. Thus, this link between regional scale productivity, growth, and subsequent year-class strength supports the hypothesis that large-scale oceanographic processes stimulating upwelling and secondary production are primary drivers of larval growth and recruitment in rockfishes.

Larvae of intertidal species develop at sea and must return to adult habitats to replenish populations. Similarly, nutrients, detritus and plankton provide important subsidies spurring growth and reproduction of macroalgae and filter-feeding invertebrates that form the foundation of intertidal communities. Together, these factors determine the density and intensity of interactions among community members. We hypothesized that spatial variation in surfzone hydrodynamics affects the delivery of plankton subsidies. We compared entire zooplankton communities inside and outside the surf zone daily while monitoring physical conditions for one month each at two shores with different surfzone characteristics. Opposite cross-shore distributions of larvae and other zooplankters occurred at the two sites: zooplankton was much more abundant inside the mildly sloping dissipative surf zone (DSZ) with rip currents and was more abundant outside the steep reflective surf zone (RSZ). Biophysical numerical simulations demonstrated that zooplankters were concentrated in rip channels of the DSZ and were mostly unable to enter the RSZ, indicating the hydrodynamic processes behind the observed spatial variation of zooplankters in the surf zone. Differences in the concentration of larvae and other zooplankters between the inner shelf and surf zone may be an underappreciated, key determinant of spatial variation in inshore communities.

Ecological connectivity can influence the distributions of diversity and productivity among ecosystems, but relationships among multiple marine ecosystems remain relatively uncharacterized. Sandy beaches are recipient ecosystems that support coastal food webs through deposits of drift macrophytes (wrack), and serve as test cases for exploring within-seascape connectivity. We present results from the first comprehensive survey of geographic and temporal patterns of wrack cover and composition on beaches along the North Central Coast of California and test the role of local donor ecosystems and physical factors in predicting wrack distribution. We surveyed wrack at 17 beaches in August 2010, and monthly at a subset of 10 beaches for 13 months. We estimated explanatory variables of (1) local donor ecosystem cover (kelp forests, rocky intertidal, and bays and estuaries), (2) biomass transport, and (3) beach morphology. Regression analyses were used to evaluate relationships among the cover of six key wrack categories and the explanatory variables above, for two time periods. We found persistent geographic variation in wrack composition and detected significant relationships between wrack cover and cover of local donor ecosystems for five of the six wrack categories (Nereocystis, Zostera, Postelsia, mixed red algae, and mixed brown algae). Transport mechanisms (wind exposure, swell exposure) or attributes of the recipient ecosystem (beach width, beach slope) explained additional spatial variation for three of the six wrack categories (Zostera, Phyllospadix, and mixed red algae). Our results support the concept of considering ecological connectivity (particularly the role of donor ecosystems upon which recipient ecosystems rely) in the design and management of protected areas.

Several studies on trait-mediated indirect interactions (TMIIs) have shown that predators can initiate trophic cascades by altering prey behaviour. Although it is well recognized that individual prey state alters antipredator and foraging behaviour, few studies explore whether this state-dependent prey behaviour can alter the strength of the ensuing tritrophic cascade. Here, we link state-dependent individual behaviour to community processes by experimentally testing whether hunger level and body size of prey altered antipredator behaviour and thus changed the strength of trophic cascades between predators and primary producers. In rocky intertidal tide pools on the California Coast, waterborne cues from the predatory seastar Leptasterias spp. (Stimpson) can cause the herbivorous snail Tegula (Chlorostoma) funebralis (A. Adams) to reduce grazing and flee tide pools, resulting in positive indirect effects on tide pool microalgae. However, we show that the strength of this behaviourally-mediated cascade may be contingent on prey hunger level and body size. During short field experiments at low tide, medium-sized snails that were either newly collected from the field or fed for 1�week in the laboratory mediated strong TMIIs because they grazed less when seastars were present. In contrast, no TMIIs occurred when medium-sized snails had been starved for 1�week because they continued grazing regardless of seastar presence. Newly collected small snails fled from seastars but did not mediate cascades because they ate little algae. Despite reaching an apparent size refuge from predation, many newly collected large snails fled from seastars, but those individuals that remained tended to graze the algae more quickly, resulting in unexpected negative indirect effects of seastars on algae cover. The implication of this pattern for the natural system is unclear. Because average hunger level and size of snails vary over time and space in nature, a mosaic of TMII strength may exist. Overall, the strength of tritrophic TMIIs in tide pools depended on individual prey state, supporting model predictions and adding to sparse empirical evidence. This outcome suggests that patterns occurring system-wide over the long term may be influenced by the state-dependent decisions made by the individuals present.

Recent syntheses on the evolutionary causes of dispersal have focused on dispersal as a direct adaptation, but many traits that influence dispersal have other functions, raising the question: when is dispersal 'for' dispersal? We review and critically evaluate the ecological causes of selection on traits that give rise to dispersal in marine and terrestrial organisms. In the sea, passive dispersal is relatively easy and specific morphological, behavioural, and physiological adaptations for dispersal are rare. Instead, there may often be selection to limit dispersal. On land, dispersal is relatively difficult without specific adaptations, which are relatively common. Although selection for dispersal is expected in both systems and traits leading to dispersal are often linked to fitness, systems may differ in the extent to which dispersal in nature arises from direct selection for dispersal or as a by-product of selection on traits with other functions. Our analysis highlights incompleteness of theories that assume a simple and direct relationship between dispersal and fitness, not just insofar as they ignore a vast array of taxa in the marine realm, but also because they may be missing critically important effects of traits influencing dispersal in all realms.

Demographic connectivity is fundamental to the persistence and resilience of metapopulations, but our understanding of the link between reproduction and recruitment is notoriously poor in open-coast marine populations. We provide the first evidence of high local retention and limited connectivity among populations spanning 700 km along an open coast in an upwelling system. Using extensive field measurements of fecundity, population size and settlement in concert with a Bayesian inverse modelling approach, we estimated that, on average, Petrolisthes cinctipes larvae disperse only 6.9 km (±25.0 km s.d.) from natal populations, despite spending approximately six weeks in an open-coast system that was once assumed to be broadly dispersive. This estimate differed substantially from our prior dispersal estimate (153.9 km) based on currents and larval duration and behaviour, revealing the importance of employing demographic data in larval dispersal estimates. Based on this estimate, we predict that demographic connectivity occurs predominantly among neighbouring populations less than 30 km apart. Comprehensive studies of larval production, settlement and connectivity are needed to advance an understanding of the ecology and evolution of life in the sea as well as to conserve ecosystems. Our novel approach provides a tractable framework for addressing these questions for species occurring in discrete coastal populations.

Most harmful algal blooms (HAB) originate away from the shore and, for them to endanger human health, they must be first transported to shore after which they must enter the surf zone where they can be feed upon by filter feeders. The last step in this sequence, entrance into the surf zone, depends on surf zone hydrodynamics. During two 30-day periods, we sampled Pseudo-nitzschia and particulate domoic acid (pDA) in and offshore of a more dissipative surf zone at Sand City, California (2010) and sampled Pseudo-nitzschia in and out of reflective surf zones at a beach and rocky shores at Carmel River State Beach, California (2011). At Sand City, we measured domoic acid in sand crabs, Emerita analoga. In the more dissipative surf zone, concentrations of Pseudo-nitzschia and pDA were an order of magnitude higher in samples from a rip current than in samples collected just seaward of the surf zone and were 1000 times more abundant than in samples from the shoals separating rip currents. Domoic acid was present in all the Emerita samples and varied directly with the concentration of pDA and Pseudo-nitzschia in the rip current. In the more reflective surf zones, Pseudo-nitzschia concentrations were 1-2 orders of magnitude lower than in samples from 125 and 20m from shore. Surf zone hydrodynamics affects the ingress of Pseudo-nitzschia into surf zones and the exposure of intertidal organisms to HABs on the inner shelf.

Seamounts have generally been identified as locations that can promote elevated productivity, biomass and predator biodiversity. These properties attract seamount-associated fisheries where elevated harvests can be obtained relative to surrounding areas. There exists large variation in the geological and oceanographic environment among the thousands of locations that fall within the broad definition of seamount. Global seamount surveys have revealed that not all seamounts are hotspots of biodiversity, and there remains a strong need to understand the mechanisms that underlie variation in species richness observed. We examined the process of fish species assembly at El Bajo Espiritu Santo (EBES) seamount in the Gulf of California over a five-year study period. To effectively quantify the relative abundance of fast-moving and schooling fishes in a 'blue water' habitat, we developed a simplified underwater visual census (UVC) methodology and analysis framework suitable for this setting and applicable to future studies in similar environments. We found correlations between seasonally changing community structure and variability in oceanographic conditions. Individual species responses to thermal habitat at EBES revealed three distinct assemblages, a 'fall assemblage' tracking warmer overall temperature, a 'spring assemblage' correlated with cooler temperature, and a 'year-round assemblage' with no significant response to temperature. Species richness was greatest in spring, when cool and warm water masses stratified the water column and a greater number of species from all three assemblages co-occurred. We discuss our findings in the context of potential mechanisms that could account for predator biodiversity at shallow seamounts.

Larvae of benthic marine organisms are released amid high densities of suspension feeding and predatory adults and are highly subject to being consumed, even by conspecifics or their own parent. During laboratory feeding trials conducted in June 2006, female shore crabs (Hemigrapsus oregonensis) from Stege Marsh in San Francisco Bay (37°54.530' N, 122°19.734' W) that released their larvae during the previous 24 h ate fewer conspecific larvae than females that had not recently released larvae, though the behavior was not repeated during similar trials in 2007. Additionally, the number of larvae eaten increased with increasing starvation time, and hungrier females showed a trend toward eating more larvae from a different species (Carcinus maenas) than larvae of conspecifics. Thus, suppression of suspension feeding may reduce conspecific predation of newly released larvae, but this response partially depends on hunger level. This is the first time crabs have been shown to suppress feeding to reduce cannibalism of larvae, and this behavior could affect reproductive success and population dynamics. © 2014 Blackwell Verlag GmbH.

Coastal development has generated multiple stressors in marine and estuarine ecosystems, including habitat degradation and pollutant exposure, but the effects of these stressors on the ecology of fishes remain poorly understood. We studied the separate and combined effects of an acute 4 h sublethal exposure of the pyrethroid pesticide esfenvalerate and structural habitat complexity on behavior and predation risk of larval topsmelt (Atherinops affinis). Larvae were exposed to four nominal esfenvalerate concentrations (control, 0.12, 0.59, 1.18 μg/L), before placement into 12 L mesocosms with a three-spine stickleback (Gasterosteus aculeatus) predator. Five treatments of artificial eelgrass included a (1) uniform and (2) patchy distribution of eelgrass at a low density (500 shoots per m(2)), a (3) uniform and (4) patchy distribution of eelgrass at a high density (1,000 shoots per m(2)), and (5) the absence of eelgrass. The capture success of predators and aggregative behavior of prey were observed in each mesocosm for 10 min of each trial, and mortality of prey was recorded after 60 min. Exposure to esfenvalerate increased the proportion of larvae with swimming abnormalities. Surprisingly, prey mortality did not increase linearly with pesticide exposure but increased with habitat structure (density of eelgrass), which may have been a consequence of compensating predator behavior. The degree of prey aggregation decreased with both habitat structure and pesticide exposure, suggesting that anti-predator behaviors by prey may have been hampered by the interactive effects of both of these factors.

Fundamental knowledge of mortality during the planktonic phase of the typical marine life cycle is essential to understanding population dynamics and managing marine resources. However, estimating larval mortality is extremely challenging, because the fate of microscopic larvae cannot be tracked as they develop for weeks in ocean currents. We used a two-pronged approach to provide reliable estimates of larval mortality: (1) frequent, long-term sampling where the combination of larval behaviors and recirculation greatly reduces larval transport to and from the study area, and (2) an improved method of calculating larval mortality that consists of a vertical life table with a negative binomial distribution to account for the notorious patchiness of plankton. Larval mortality rates of our study species (barnacles and crabs) were ≤0.14 larvae/d, which produce survivorships over an order of magnitude higher than commonly determined for marine larvae. These estimates are reliable because they were similar for species with similar dispersal patterns. They are conservative because they were conducted in a highly advective upwelling system, and they may be even lower in other systems using our approach. Until other systems can be tested, our improved estimates should be used to inform future models of population dynamics and the evolution of life histories in the sea.

The effectiveness of larval behavior in regulating transport between well-mixed, low-inflow estuaries and coastal waters in seasonally arid climates is poorly known. We determined the flux of an assemblage of benthic crustacean larvae relative to physical conditions between a shallow estuary and coastal waters on the upwelling coast of northern California (38°18′N, 123°03′W) from 29 to 31 March 2006. We detected larval behaviors that regulate transport in adjacent coastal waters and other estuaries for only two taxa in the low-inflow estuary, but they were apparent for taxa outside the estuary. Vertical mixing in the shallow estuary may have overwhelmed larvae of some species, or salinity fluctuations may have been too slight to cue tidal vertical migrations. Nevertheless, all larval stages of species that complete development in nearshore coastal waters were present in the estuary, because they remained low in the water column reducing seaward advection or they were readily exchanged between the estuary and open coast by tidal flows. Weak tidal flows and gravitational circulation at the head of the estuary reduced seaward transport during development for species that completed development nearshore, whereas larval release during nocturnal ebb tides enhanced seaward transport for species that develop offshore. Thus, nonselective tidal processes dominated larval transport for most species back and forth between the low-inflow estuary and open coastal waters, whereas in adjacent open coastal waters, larval behavior in the presence of wind-induced shear was more important in regulating migrations between adult and larval habitats along this upwelling coast. © 2014 Coastal and Estuarine Research Federation.

Highly advective upwelling systems along the western margins of continents are widely believed to transport larvae far offshore in surface currents resulting in larval wastage, limited recruitment, and increased population connectivity. However, suites of larval behaviors effectively mediate interspecific differences in the extent of cross-shelf migrations between nearshore adult habitats and offshore larval habitats. Interspecific differences in behavior determining whether larvae complete development in estuaries or migrate to the continental shelf are evident in large estuaries, but they sometimes may be disrupted by turbulent tidal flow or the absence of a low-salinity cue in shallow, low-flow estuaries, which are widespread in upwelling systems. Larvae of most species on the continental shelf complete development in the coastal boundary layer of reduced flow, whereas other species migrate to the mid- or outer shelf depending on how much time is spent in surface currents. These migrations are maintained across latitudinal differences in the strength and persistence of upwelling, in upwelling jets at headlands, over upwelling-relaxation cycles, and among years of varying upwelling intensity. Incorporating larval behaviors into numerical models demonstrates that larvae recruit closer to home and in higher numbers than when larvae disperse passively or remain in surface currents.

Competent larvae of intertidal invertebrates have to migrate toward shore for settlement; however, their migration through the surf zone is not understood. We investigated larval transport mechanisms at a rip-channeled beach. Because tracking larvae in the surf zone is infeasible, we used a three-dimensional biophysical model to simulate the processes. The coupled model consists of a physical module for currents and waves, and a biological module for adding larval traits and behaviors as well as Stokes drift to Lagrangian particles. Model calculations were performed with and without onshore wind forcing. Without wind, wave-driven onshore streaming occurs in the bottom boundary layer outside the surf zone. With onshore wind, onshore currents occur near the surface. In the surf zone, offshore-directed rip currents and compensating onshore-directed currents over shoals are formed in both no-wind and wind cases. In the biological module, neutral, negative, and positive buoyant particles were released offshore. Additionally, particles either sank in the presence of turbulence or not. Two scenarios achieved successful onshore migration: Negatively buoyant larvae without wind forcing sink in the turbulent bottom boundary layer and are carried onshore by streaming; positively buoyant larvae drift toward shore in wind-driven surface currents to the surf zone, then sink in the turbulent surf zone and remain near the bottom while transported shoreward. In both cases, the larval concentration is highest in the rip channel, consistent with field data. This successful result is only obtained if turbulence-dependent sinking behavior and Stokes drift are included in the transport of larvae. © 2014, by the Association for the Sciences of Limnology and Oceanography, Inc.

Many marine species minimize predation during hatching or spawning by releasing larvae or gametes synchronously during nocturnal spring ebb tides. Propagules are then rapidly transported away from high densities of predatory fishes into deeper waters under the cover of darkness. Females also suspend foraging in the presence of predators, but it is unknown whether they are able to delay releasing larvae. In a previous study, we found that larval release is only weakly synchronized to the safe period in a cold upwelling region, although the study was conducted on outdoor seawater tables in the absence of tides that reinforce endogenous rhythms. In this study, we experimentally determined whether larval release 1) is better synchronized in the field and 2) delayed in the presence of predatory fishes. Larval release was weakly synchronized to tidal amplitude, tidal and diel cycles, occurring from late flood to late ebb tide on both intermediate and spring tides during twilight as well as darkness. Weak synchrony likely arises because cold temperatures extend incubation of externally brooded embryos, increasing exposure to environmental variation. Larval release was not delayed in the presence of predatory fishes; nor was refuge use or other behaviors of females altered by fishes. Behaviors were not affected by predators presumably because larvae are already being released near the safe period from refuges. Our results likely apply to other cold regions of the world, but it remains to be determined whether predators alter the activities of nonovigerous female and male shore crabs, which may not spend as much time in refuges as ovigerous females, potentially resulting in cascading effects on communities. © 2014 Elsevier B.V.

Demographic connectivity is a fundamental process influencing the dynamics and persistence of spatially structured populations. Consequently, quantifying connectivity is essential for properly designing networks of protected areas so that they achieve their core ecological objective of maintaining population persistence. Recently, many empirical studies in marine systems have provided essential, and historically challenging to obtain, data on patterns of larval dispersal and export from marine protected areas (MPAs). Here, we review the empirical studies that have directly quantified the origins and destinations of individual larvae and assess those studies' relevance to the theory of population persistence and MPA design objectives. We found that empirical studies often do not measure or present quantities that are relevant to assessing population persistence, even though most studies were motivated or contextualized by MPA applications. Persistence of spatial populations, like nonspatial populations, depends on replacement, whether individuals reproduce enough in their lifetime to replace themselves. In spatial populations, one needs to account for the effect of larval dispersal on future recruitment back to the local population through local retention and other connectivity pathways. The most commonly reported descriptor of larval dispersal was the fraction of recruitment from local origin (self-recruitment). Self-recruitment does not inform persistence-based MPA design because it is a fraction of those arriving, not a fraction of those leaving (local retention), so contains no information on replacement. Some studies presented connectivity matrices, which can inform assessments of persistence with additional knowledge of survival and fecundity after recruitment. Some studies collected data in addition to larval dispersal that could inform assessments of population persistence but which were not presented in that way. We describe how three pieces of empirical information are needed to fully describe population persistence in a network of MPAs: (1) lifetime fecundity, (2) the proportion of larvae that are locally retained (or the full connectivity matrix), and (3) survival rate after recruitment. We conclude by linking theory and data to provide detailed guidance to empiricists and practitioners on field sampling design and data presentation that better informs the MPA objective of population persistence.

Collaborative fisheries research programs engage stakeholders in data collection efforts, often with the benefit of increasing transparency about the status and management of natural resources. These programs are particularly important in marine systems, where management of recreational and commercial fisheries have historically been contentious. One such program is the California Collaborative Fisheries Research Program (CCFRP), which was designed in 2006 to engage recreational anglers in the scientific process and evaluate the efficacy of California's network of marine protected areas. CCFRP began on the Central Coast of California and expanded statewide in 2017 to include six partner institutions in three regions: Northern, Central, and Southern California. To date, over 2,000 volunteer anglers have participated in the program, with many anglers volunteering for multiple years. However, the impacts of outreach, education, and collaborative research on those anglers at the statewide scale are currently unknown. Thus, the objective of the current study was to survey the statewide pool of volunteer anglers to assess the degree to which participation in CCFRP has influenced angler perceptions of MPAs, fisheries management, and conservation. We received 259 completed surveys out of a pool of 1,386 active anglers, equating to an 18.7% response rate. Participation in CCFRP resulted in a significant, positive impact on anglers' attitudes towards MPAs in California across all regions. Anglers who participated in six or more CCFRP fishing trips had a more positive perception of MPAs than those who participated in fewer trips. Volunteer anglers across all regions perceived that they caught larger fishes, a higher abundance of fishes, and a greater diversity of species inside MPAs, consistent with the ecological findings of the program. These results highlight the benefits of involving community members in collaborative scientific research. Collaboration between researchers and the broader community increases transparency and trust between stakeholders, and results in greater understanding of natural resource dynamics, ultimately producing better management outcomes. [ABSTRACT FROM AUTHOR]

The timing of vertical migrations by newly-hatched larvae determines the extent of transport away from adult populations and exposure to predatory fishes, but it is largely unknown whether larval swimming behavior is a fixed trait or changes adaptively in response to different ocean conditions that are encountered between habitats. We determined whether larvae of the shore crab, Pachygrapsus crassipes, hatched in the San Francisco Estuary and those hatched nearby on the outer coast undertake tidal and diel vertical migrations. Vertical swimming of larvae that were released by females collected from the two locations were recorded in the laboratory for up to four days in constant darkness without a tidal cycle to detect the presence of endogenous tidal and diel vertical migrations. P. crassipes larvae from the outer coast population did not exhibit rhythmic vertical migrations, remaining near the surface throughout the day, whereas larvae from the estuarine population did undertake complex vertical migrations relative to tidal and diel cycles. Although current patterns differ on the open coast and in the estuary, remaining in surface waters at both locations would favor seaward transport of larvae to offshore nursery areas. However, undertaking tidal vertical migrations in estuaries would expedite seaward transport while increasing the risk of fish predation during the daytime. The differences in behaviors are likely phenotypic, because larvae came from neighboring populations and intermingle in offshore larval nursery areas. This spatial variation in larval swimming behavior among habitats enhances transport to offshore nursery areas. © 2013.

Using an implementation of the Region Ocean Modeling System, we investigate the influence of larval vertical swimming on spring dispersal for nearshore invertebrate species in the California Current System (CCS), with a focus on central California and the Bodega Bay area. Larvae are given a suite of idealized behaviors designed to reveal the importance of the surface boundary layer (SBL) to transport and settlement. Larvae remain near 5 m, 30 m, or transition between these depths using various strategies, including diel vertical migration (DVM) and ontogenetic vertical migration. Some behaviors result in modeled densities qualitatively similar to observed cross-shelf larval distributions. By remaining primarily below the SBL, larvae released from central California are 500 times more likely to be retained within 5 km of the coast at 30 days from release relative to those that stay near surface, and 145 times more likely to settle along the coast within a 30 to 60 day pelagic larval duration. For most behaviors, nearshore retention over time could be approximated as a modified exponential decay process. Vertical swimming also greatly affects alongshore dispersal, with each behavior resulting in a unique structure of alongshore settlement. Maintaining a depth near 30 m increases settlement throughout most of the CCS by at least an order of magnitude relative to passive larvae. Remaining near surface reduces settlement from Pt. Conception to Pt. Arena, but has less of an effect north of Cape Mendocino. Relative to passive larvae, DVM increases settlement in regional "hotspots," but does not greatly alter overall recruitment in the CCS, and ontogenetic vertical migration increases settlement for central California regions south of Bodega Bay. © 2013 Patrick T. Drake, Christopher A. Edwards, Steven G. Morgan and Edward P. Dever.

Genetic diversity has emerged as an important source of variation in the ecological properties of populations, but there are few studies of genetic diversity effects on colonisation processes. This relative scarcity of studies is surprising given the influence of colonisation on species coexistence, invasion, and population persistence. Here, we manipulated relatedness in experimental populations of colonising larvae in four sessile marine invertebrates. We then examined the influence of coloniser relatedness on the number, spatial arrangement and phenotype of colonisers following permanent settlement. Overall, relatedness influenced colonisation in all four species, but the effects of relatedness on colonisation differed among species. The variable responses of species to manipulations of relatedness likely reflect differences in intensity of inter- and intra-specific competition among adults, as well as the differential consequences of larval behaviours for each species. Relatedness appears to play an underappreciated role in the colonisation process, and we recommend that future studies of genetic diversity effects consider not only adult stages - the focus of most work to date - but also the importance of genetic diversity in early life history stages. © 2012 The Authors. Oikos © 2012 Nordic Society Oikos.

The objective of this study was to evaluate the efficacy of integrating a traditional sediment quality triad approach with selected sublethal chronic indicators in resident species in assessing sediment quality in four salt marshes in northern California, USA. These included the highly contaminated (Stege Marsh) and relatively clean (China Camp) marshes in San Francisco Bay and two reference marshes in Tomales Bay. Toxicity potential of contaminants and benthic macroinvertebrate survey showed significant differences between contaminated and reference marshes. Sublethal responses (e.g., apoptotic DNA fragmentation, lipid accumulation, and glycogen depletion) in livers of longjaw mudsucker (Gillichthys mirabilis) and embryo abnormality in lined shore crab (Pachygrapsus crassipes) also clearly distinguished contaminated and reference marshes, while other responses (e.g., cytochrome P450, metallothionein) did not. This study demonstrates that additional chronic sublethal responses in resident species under field exposure conditions can be readily combined with sediment quality triads for an expanded multiple lines of evidence approach. This confirmatory step may be warranted in environments like salt marshes in which natural variables may affect interpretation of toxicity test data. Qualitative and quantitative integration of the portfolio of responses in resident species and traditional approach can support a more comprehensive and informative sediment quality assessment in salt marshes and possibly other habitat types as well.