Microplastic in northern anchovies (Engraulis mordax) and common murres (Uria aalge) from the Monterey Bay, California USA - Insights into prevalence, composition, and estrogenic activity

HIGH-FREQUENCY (HF) radar measurements have been employed around Monterey Bay, CA, to measure ocean surface currents since February 1992. The first array consisted of two older-generation CODAR instruments located at sites near Monterey in the south and Moss Landing, halfway around the bay to the north (Front Cover: Fig. 1). In 1994, the southern site was replaced with a newer-generation SeaSonde system at Pt. Pinos and a similar unit was installed near Santa Cruz on the northern shore of Monterey Bay. Finally, in 1996, the CODAR system in Moss Landing was replaced by a modern SeaSonde unit. Several months time series of two-dimensional surface currents have been collected for Monterey Bay since the first CODAR units were installed. These data represent the most extensive measurements collected to date from compact, directionfinding HF radar systems (Barrick and Lipa, 1997: Paduan and Graber, 1997). Indeed, Monterey Bay is the only location where continuous HF radar measurements are underway. The geometry of the bay (a curving coastline with a radius of -20 km) is ideal for a multisite HF radar network. The overwater distance is close to the typical radar range and, when three or more shore locations are utilized, the entire region can be observed without lost coverage along the baseline between radar sites. This geometry also makes Monterey Bay well suited for validation and development of the algorithms for currents, waves, and wind direction because a large ocean region is oversampled. Not only can in situ measurements within this region be compared with the remotely sensed estimates, but self-consistency (or lack thereof) in the HF radar measurements can be used to characterize errors in the radar data (Melton, 1995).

Environmental conditions and prey-switching by a seabird predator impact juvenile salmon survival

A shift in the dominant toxin-producing algal species in central California alters phycotoxins in food webs

The central California coast is a highly productive, biodiverse region that is frequently affected by the toxin-producing dinoflagellate Alexandrium catenella. Despite the consistent presence of A. catenella along our coast, very little is known about the movement of its toxins through local marine food webs. In the present study, we investigated 13 species of commercial finfish and rock crabs harvested in Monterey Bay, California for the presence of paralytic shellfish toxins (PSTs) and compared them to the presence of A. catenella and PSTs in sentinel shellfish over a 3-year period. Between 2003 and 2005, A. catenella was noted in 55% of surface water samples (n = 307) and reached a maximum concentration of 17,387 cells L−1 at our nearshore site in Monterey Bay. Peak cell densities occurred in the month of July and were associated with elevated shellfish toxicity in the summers of 2004 and 2005. When A. catenella was present, particulate PSTs were detected 71% of the time and reached a maximum concentration of 962 ng STXeq L−1. Of the 13 species tested, we frequently detected PSTs in Pacific sardines (Sardinops sagax; maximum 250 μg STXeq 100 g−1), northern anchovies (Engraulis mordax; maximum 23.2 μg STXeq 100 g−1), brown rock crabs (Cancer antennarius; maximum 49.3 μg STXeq 100 g−1) and red rock crabs (C. productus; 23.8 μg STXeq 100 g−1). PSTs were also present in one sample of Pacific herring (Clupea pallas; 13.3 μg STXeq 100 g−1) and one sample of English sole (Pleuronectes vetulus; 4.5 μg STXeq 100 g−1), and not detected in seven other species of flatfish tested. The presence of PSTs in several of these organisms reveals that toxins produced by A. catenella are more prevalent in California food webs than previously thought and also indicates potential routes of toxin transfer to higher trophic levels.Electronic supplementary materialThe online version of this article (doi:10.1007/s00227-008-1103-z) contains supplementary material, which is available to authorized users.

A three dimensional coastal ocean system for Monterey Bay (MOB) is developed using numerical grid generation to study the summer circulation. The system is a primitive equation coastal ocean modeling system, which consists of a coastal ocean model, numerical grid generation routines, and a grid package which allows the model to be coupled to model grids. In this coastal ocean system, a curvilinear nearly-orthogonal (CNO) grid is used to enhance the model numerical solution. The MOB model has 28 sigma vertical levels, and the CNO coastlinefollowing numerical grid has 131 x 131 grid points, which cover a domain of 150 km by 150 km. The model has horizontal resolutions of 200 m to 2 km, free surface dynamics, and realistic coastlines and bottom bathymetry. The model code is written for a multi-block grid, but a single-block CNO grid is demonstrated for the MOB simulations. The MOB model and the associated grid are used to simulate summer circulation and reproduce the MOB basic physics such as coastal currents and upwelling locations.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 287:23-32 (2005) - doi:10.3354/meps287023 Physical-biological coupling in Monterey Bay, California: topographic influences on phytoplankton ecology John P. Ryan*, Francisco P. Chavez, James G. Bellingham Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, California 95039-9644, USA *Email: ryjo@mbari.org ABSTRACT: Physical-biological couplings impacting phytoplankton ecology are examined with synoptic, high-resolution observations of Monterey Bay, California. Influences of submarine canyon and shelf break topography on the physical-biological couplings are supported by 2 case studies. In the first case study, benthic-pelagic coupling was observed in southern shelf waters where a turbid plume extended from the bottom at ~60 m deep to the base of a phytoplankton layer centered at ~10 m deep. The alongshelf scale of the plume ranged from ~5 km near the bottom to ~1 km at its intersection with the phytoplankton layer. In situ and remote sensing data support the influence of Monterey Canyon on circulation forcing the benthic-pelagic coupling. In the second case study, a frontal zone and adjacent waters were rapidly surveyed over ~20 km2 of the northern shelf. The front was associated with an isopycnal ridge/trough structure, surface slick, and frontal eddy <1 km in diameter. The magnitude and vertical location of a chlorophyll maximum layer were closely coupled with the physical environment through the frontal zone. The layer was dispersed by the isopycnal ridge and frontal eddy, and concentrated in the isopycnal trough and along the periphery of the eddy. Influence of an internal wave generated by interaction of tidal currents with the shelf break is supported by the observed surface slick, measured water velocities, and the proximity and orientation of the shelf break. Significant and persistent influences of topography on phytoplankton ecology in Monterey Bay are indicated. KEY WORDS: Physical-biological coupling · Topographic influence · Fronts · Eddies · Phytoplankton · Benthic-pelagic coupling · Submarine canyons · Autonomous underwater vehicle Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 287. Online publication date: February 18, 2005 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2005 Inter-Research.

Globally, small-scale fisheries are influenced by dynamic climate, governance, and market drivers, which present social and ecological challenges and opportunities. It is difficult to manage fisheries adaptively for fluctuating drivers, except to allow participants to shift effort among multiple fisheries. Adapting to changing conditions allows small-scale fishery participants to survive economic and environmental disturbances and benefit from optimal conditions. This study explores the relative influence of large-scale drivers on shifts in effort and outcomes among three closely linked fisheries in Monterey Bay since the Magnuson-Stevens Fisheries Conservation and Management Act of 1976. In this region, Pacific sardine (Sardinops sagax), northern anchovy (Engraulis mordax), and market squid (Loligo opalescens) fisheries comprise a tightly linked system where shifting focus among fisheries is a key element to adaptive capacity and reduced social and ecological vulnerability. Using a cluster analysis of landings, we identify four modes from 1974 to 2012 that are dominated (i.e., a given species accounting for the plurality of landings) by squid, sardine, anchovy, or lack any dominance, and seven points of transition among these periods. This approach enables us to determine which drivers are associated with each mode and each transition. Overall, we show that market and climate drivers are predominantly attributed to dominance transitions. Model selection of external drivers indicates that governance phases, reflected as perceived abundance, dictate long-term outcomes. Our findings suggest that globally, small-scale fishery managers should consider enabling shifts in effort among fisheries and retaining existing flexibility, as adaptive capacity is a critical determinant for social and ecological resilience.

To assess competition between commercial fisheries and California sea lion (Zalophus californianus) in Monterey Bay, California I estimated sea lion seasonal abundance, seasonal food habits, annual fish consumption, and percentages of hooked fish taken by sea lions in commercial and recreational salmon fisheries during 1997 and 1998. Aerial and ground surveys indicated that peak numbers of sea lions occurred during their spring and fall migration. While sahnon occurred in the sea lion diet year-round, sea lions primarily consumed schooling prey such as market squid (Loligo opalescens), Pacific sardine (Sardinops sagax), and northern anchovy (Engraulis mordax). Increased depredation of the salmon catch by sea lions in 1998 was most likely the result of the large 1997-1998 El Nino event. Hooked salmon from the fisheries were likely the majority of salmon in the sea lion diet. Assessing the impact of sea lions and other natural predators on prey populations is difficult, but necessary for effective fisheries management.

A barotropic tidal model is developed for the Monterey Bay (MOB) region, based on the multi-block grid code but using only a single-block grid. The model has realistic bathymetry with high resolution of 2 km x 2 km and covers a domain of 160 km x 160 km. The model is forced on the boundaries by four semi-diurnal (M2,S2,N2,K2) and four diurnal (K1,O1,P1,Q1) tidal constituents. The model study covers the one-month period of June 1996, and comparisons are made between the model output water levels and the tide gauge station data from Monterey, Moss Landing, and Santa Cruz. The model is used to study barotropic tides and their sensitivity to various open boundary conditions (OBC). Two common OBC, the clamped and the Reid and Bodine (RB) conditions, and a modified RB OBC are used to study barotropic tides. It is found that the barotropic model tide in the MOB region is very sensitive to the OBC. The two commonly used OBC reproduce the surface elevation reasonably well, but do not filter out long wave energy from the interior of the model domain for the MOB region. They may work well for shallow water applications, but changes are required for regions with steep bathymetry. For the MOB region the modified OBC developed in this study gives better results than the two commonly used OBC.

Thin layers of phytoplankton have an important impact on coastal ocean ecology. The high spatial and temporal variability of such layers makes autonomous underwater vehicles (AUVs) ideal for their study. At the Monterey Bay Aquarium Research Institute (MBARI, Moss Landing, CA), the authors have used an AUV for obtaining repeated high-resolution surveys of thin layers in Monterey Bay, CA. The AUV is equipped with ten "gulpers" that can capture water samples when some feature is detected. In this paper, the authors present an adaptive triggering method for an AUV to capture water samples at chlorophyll fluorescence peaks in a thin layer. The algorithm keeps track of the fluorescence background level and the peaks' baseline in real time to ensure that detection is tuned to the ambient conditions. The algorithm crosschecks for concurrent high values of optical backscattering to ensure that sampling targets true particle peaks and not simply physiologically controlled fluorescence peaks. To let the AUV capture the thin layer's peak without delay, the algorithm takes advantage of the vehicle's sawtooth (i.e., yo-yo) trajectory: in one yo-yo cycle, the vehicle makes two crossings of the thin layer. On the first crossing, the vehicle detects the layer's fluorescence peak and saves the peak height; on the second crossing, as the fluorescence measurement reaches the saved peak height (plus meeting additional timing and depth conditions), a sampling is triggered. Based on the thin layer's vertical position in the vehicle's yo-yo profiles, the algorithm selects the pair of detection and triggering crossings so as to minimize the spacing between them. We use the algorithm to postprocess a data set of 20 AUV missions in the 2005 Layered Organization in the Coastal Ocean (LOCO) Experiment in Monterey Bay, CA, and compare its performance with that of a threshold triggering method. In October 2009, the presented method was field tested in an AUV mission in northern Monterey Bay, CA.

Marine bird aggregations associated with the tidally-driven plume and plume fronts of the Columbia River

Marine predator–prey interactions are often influenced by oceanographic processes that aggregate prey. We examined density distributions of seabirds and prey fish associated with the Columbia River plume to determine whether variation in plume size (i.e., volume or surface area) or location influences predator–prey interactions. Common murre (Uria aalge), sooty shearwater (Ardenna grisea), and forage fish, including northern anchovy (Engraulis mordax) and juvenile salmon (Oncorhynchus spp.), occurred disproportionately in plume waters relative to adjacent marine waters. Water clarity, an indicator of plume-influenced waters, was a significant predictor of seabird and prey densities throughout the survey area. Murres occurred within 20 km of the plume center of gravity, whereas shearwaters occurred ∼100 km north of the plume center of gravity, concurrent with the highest densities of prey fish. Global indices of collocation were relatively low between murres and prey compared with the high values between shearwaters and prey. Seabird densities were negatively correlated with plume size, suggesting that seabirds concentrate in the plume to maximize foraging effort. We conclude that variation in Columbia River plume size and location influences predator distributions, which increases predation pressure on prey, including threatened salmonid species.

In this study, we present the levels of organochlorine (∑DDT, ∑HCH, ∑chlordane, HCB, and ∑PCBs) and metal (Pb, Hg, and Se) contaminants and their relationship to stable carbon and nitrogen isotope values in the Gulf of the Farallones marine food web. This food web consisted of two species of euphausiids (Euphausia pacifica and Thysanoessa spinifera), two fish species [short-bellied rockfish (Sebastes jordani) and anchovy (Engraulis mordax)], four bird species [common murre (Uria aalge), Brandt's cormorant (Phalacrocorax penicillatus), rhinoceros auklet (Cerorhinca monocerata), and pigeon guillemot (Cepphus columba)], and the northern sea lion (Eumetopias jubatus). We used a novel method of using egg albumen to determine stable isotope values. The values of δ13C ranged from −20.1‰ in the euphausiids to −15.0‰ in the northern sea lion and were consistant with a pelagic/offshore vs benthic/inshore results found in other studies. Values of δ15N in the Gulf of the Farallones food web ranged from 11.2‰ in the e...

Forage fishes are key energy conduits that transfer primary and secondary productivity to higher trophic levels. As novel environmental conditions caused by climate change alter ecosystems and predator-prey dynamics, there is a critical need to understand how forage fish control bottom-up forcing of food web dynamics. In the northeast Pacific, northern anchovy (Engraulis mordax) is an important forage species with high interannual variability in population size that subsequently impacts the foraging and reproductive ecology of marine predators. Anchovy habitat suitability from a species distribution model (SDM) was assessed as an indicator of the diet, distribution and reproduction of four predator species. Across 22 years (1998-2019), this anchovy ecosystem indicator (AEI) was significantly positively correlated with diet composition of all species and the distribution of common murres (Uria aalge), Brandt's cormorants (Phalacrocorax penicillatus) and California sea lions (Zalophus californianus), but not rhinoceros auklets (Cerorhinca monocerata). The capacity for the AEI to explain variability in predator reproduction varied by species but was strongest with cormorants and sea lions. The AEI demonstrates the utility of forage SDMs in creating ecosystem indicators to guide ecosystem-based management.

**Abstract:** The Columbia River on the west coast of the United States is the 21st largest river in the world in terms of annual mean flow. Freshwater discharge from the Columbia River flows into the northern California Current Ecosystem, one of the most productive marine food webs in the world. A large, dynamic plume is formed at the mouth of the river, which has a strong regional influence on nearshore oceanography and productivity. Using at-sea surveys, land-based surveys, and satellite telemetry, we demonstrated that the plume also strongly affects the distribution, abundance, and habitat preferences of seabirds and seabird prey. Specifically, we found that two numerically dominant piscivorous seabirds, common murres (Uria aalge) and sooty shearwaters (Ardenna grisea), aggregate in large numbers in this region, preferentially select plume habitat, and respond to spatial and temporal changes in plume dynamics. Coastal pelagic fishes consumed by seabirds such as northern anchovy (Engraulis mordax) are disproportionately more abundant in plume waters compared to adjacent waters, suggesting that foraging birds use the plume to increase prey encounter probabilities. Plume effects are evident in both summer and winter, although the dynamics driving winter use of the plume are not well-understood. Given predicted changes in freshwater runoff with climate change, and high levels of human use of the Columbia River and other large rivers for commercial and recreational activities, we suggest that river plumes are under-appreciated regions of global conservation importance for seabirds. **Authors:** Jeannette Zamon¹, Elizabeth Phillips², Josh Adams³ ¹NOAA Fisheries - Pt. Adams Research Station, ²NOAA Fisheries - Northwest Fisheries Science Center, ³US Geological Survey