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Costa Mesa, CA, United States

Miller E.F.,MBC Applied Environmental science | Erisman B.,University of California at San Diego
California Cooperative Oceanic Fisheries Investigations Reports | Year: 2014

Power plant entrapment monitoring data provided insights on conditions leading up to and contributing to previously documented collapses of the southern California kelp bass (Paralabrax clathratus) and barred sand bass (P. nebulifer) fisheries. Individuals from all size classes from both species were taken over time at three sites spanning nearly 100 km along the southern California coast. Size class abundance peaked in the 200 to 250 mm SL size classes, or near the minimum size limit for the two southern California fisheries (250 mm SL). Annual modal lengths remained relatively static in P. clathratus, but significantly declined in P. nebulifer with a strong downsizing after 1993. Abundance indices for each species significantly declined over nearly four decades of monitoring: 97% in P. clathratus and 86% in P. nebulifer. Evidence suggests sporadic larval settlement by each species led to occasionally abundant year classes, such as 1982 (P. clathratus) and 1994 (P. nebulifer), interspersed with several consecutive years of comparably minimal settlement. No significant correlations with common climate indices including the Multivariate ENSO Index, Pacific Decadal Oscillation, and North Pacific Gyre Oscillation were detected for either species' yearclass abundance index. The P. nebulifer year-class abundance index did significantly correlate, albeit weakly, with annual mean sea surface temperature. These results signify that, at this time, no environmental proxy for either species larval settlement exists. Source

Miller E.F.,MBC Applied Environmental science
Journal of Coastal Research | Year: 2014

On 8 March 2011, hypoxic conditions resulted in the loss of ca. 1.5 million Sardinops sagax in King Harbor, Redondo Beach, California. Uncertainty remains regarding the school's entrance into the harbor and the hydrographic conditions leading up to the event. Unusually depressed dissolved oxygen concentrations and acidic pH at 4-7 m depth in the main channel of the harbor were recorded on February 22 during permit-required power plant discharge monitoring. Similarly minimal tidal amplitude occurred on 22 February and 8 March, resulting in minimal seawater exchange within the harbor. Power plant impingement surveys at the nearby generating station began observing S. sagax in January, with an order of magnitude more individuals impinged on 3 February than any prior 24-hour survey and continued impingement occurring at above average levels through February. The data suggested the school entered in late January and might have remained through February at depth. When the 8 March neap tide occurred, hypoxic conditions developed in Basin 1, the most secluded basin, leading to the fish kill. © Coastal Education & Research Foundation 2014. Source

Parnell P.E.,University of California at San Diego | Miller E.F.,MBC Applied Environmental science | Lennert-Cody C.E.,Inter American Tropical Tuna Commission | Dayton P.K.,University of California at San Diego | And 2 more authors.
Limnology and Oceanography | Year: 2010

The nutrient climate on the inner shelf off southern California changed markedly across the 1976-1977 North Pacific climate regime shift. With respect to giant kelp (Macrocystis pyrifera) canopies off southern California, the nitrate climate shifted from relatively replete conditions prior to the regime shift to depleted conditions afterward, and the dynamics of 14 giant kelp forests appeared to change as a result. The response of giant kelp to nutrientreplete years before the regime shift was dampened compared to their response afterward. The sensitivity of these kelp-forest canopies to nutrient limitation appears to have increased since the regime shift. This intensification of physical control after 1977 is evident in the strong correlation of seawater density (σt) and M. pyrifera density. The linear fit of the percent of time the 25.1 σt isopycnal bathes the inner shelf, accounted for ∼71% of the variability in kelp density off Point Loma, and the median depth of this isopycnal has deepened ∼5 m since the regime shift. The wave climate also intensified beginning in the early 1970s. The dampened kelp response prior to the regime shift was likely due to greater biological control of kelp canopies via consumer and competitive processes (i.e., biological modulation) or decreased physical control at possibly many trophic levels. Our results suggest that the response of kelp forests to El Niño Southern Oscillation events is mediated by lower frequency climate modes that may modulate the regulatory importance of biological and physical processes on giant kelp. © 2010, by the American Society of Limnology and Oceanography, Inc. Source

Koslow J.A.,University of California at San Diego | Miller E.F.,MBC Applied Environmental science | McGowan J.A.,University of California at San Diego
Marine Ecology Progress Series | Year: 2015

The California Cooperative Oceanic Fisheries Investigations (CalCOFI) ichthyoplankton surveys and systematic sampling of southern California power plant cooling-water intakes (PPI) provide independent, complementary time series to assess fish communities off southern California from nearshore to oceanic environments. The PPI program has sampled the shallow nearshore fish community at 5 sites along the coast of southern California since 1972, while CalCOFI has sampled fish larvae along 6 transects at standard stations ranging from 35 m depth to more than 500 km offshore since 1951. Recently published analyses of these data sets led us to examine potential relationships between them. Although there was limited overlap in the taxa sampled by the 2 programs, key multivariate patterns were highly correlated between them. Both time series exhibited dramatic declines from the 1970s to the 2000s: 78% for fishes entrapped by the power plants and 72% for the overall abundance of larval fishes in the CalCOFI time series. These trends, which predominantly affected taxa with cool-water affinities, were shared by fishes across nearshore and oceanic habitats, and included several trophic guilds and many unfished or only lightly fished taxa. These declines were significantly correlated with declining zooplankton displacement volumes across the California Current System (CCS), which suggests the influence of large-scale climatic and oceanographic drivers. Over the past 4 decades, changing environmental conditions appear to have produced more losers than winners in the CCS. © 2015 Inter-Research. Source

Miller E.F.,MBC Applied Environmental science | McGowan J.A.,University of California at San Diego
Estuarine, Coastal and Shelf Science | Year: 2013

Trends in coastal fish abundance indices were examined using a novel 39-year (1972-2010) time series recorded at southern California coastal power plants. Since 1972, the annual mean abundance index significantly declined (r2=0.45, p<0.001). The mean annual biomass index likewise declined but with a large interruption in 2005-2006 when an influx of large bodied, southern species increased the annual means. Ensemble mean abundance indices for fished and unfished species declined at similar rates. Two faunal shifts were identified, 1983-1984 and 1989-1990. The ensemble mean, annual entrapment rate abundance index during the current period (1990-2010) represents only 22% of that recorded during the first and most abundant period, 1972-1983. The mean biogeographic distribution of the assemblage was non-linear over time including a shift south during the 1980s through the 1990s before shifting north in recent years. The northern shift in recent years accompanied higher variability than previously recorded and was likely related to the overall low abundance. Since the early 1980s, the mean trophic level derived from abundance declined. The observed patterns were not correlated with commonly employed composite indices such as the Pacific Decadal Oscillation, but did show some sensitivity to changes in coastal seawater temperature and density over time. Timing of the observed faunal shifts in the fish assemblage was consistent with reported oceanographic shifts. These data suggested factors beyond fishing, such as oceanographic change, have substantially impacted the coastal fishes of southern California. © 2013 Elsevier Ltd. Source

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