Red Bluff, CA, United States
Red Bluff, CA, United States

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Erisman B.E.,University of California at San Diego | Allen L.G.,California State University, Northridge | Claisse J.T.,Occidental College | Pondella D.J.,Occidental College | And 2 more authors.
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2011

Fisheries that target fish spawning aggregations can exhibit hyperstability, in which catch per unit effort (CPUE) remains elevated as stock abundance declines, but empirical support is limited. We compiled several fishery-dependent and fishery-independent data sets to assess stock trends in the barred sand bass (Paralabrax nebulifer) and the kelp bass (Paral-abrax clathratus) in southern California, USA, evaluate the interaction between spawning aggregations and fishing activities, and test for hyperstability. Annual and seasonal trends from fisheries and population data indicate that regional stocks of both species have collapsed in response to overfishing of spawning aggregations and changes in environmental conditions. The aggregating behavior of fish and persistent targeting of spawning aggregations by recreational fisheries combined to produce a hyperstable relationship between CPUE and stock abundance in both species, which created the illusion that population levels were stable and masked fishery collapses. Differences in the rate of decline between the two species may be related to the size, duration, and spatial distribution of their spawning aggregations. Results of this study provide empirical evidence of hyperstability in aggregation-based fisheries and demonstrate that CPUE data be used with caution and given low weight when fishery-independent data are available.

Miller E.F.,MBC Applied Environmental science | Williams J.P.,Occidental College | Pondella D.J.,Occidental College
California Cooperative Oceanic Fisheries Investigations Reports | Year: 2011

Larval Genyonemus lineatus and Seriphus politus collected using bongo frames fatted with 0.333 mm mesh nets between December 2003 and September 2004 of Huntington Beach, California, were examined to characterize their daily growth patterns. Samples from one net were fixed in a 4% buffered formalin-seawater solution while those from the other net were preserved in 70% ethanol. All formalin-fixed samples were transferred to 70% ethanol ~72 hours after collection. Growth was best described by a linear equation for G. lineatus (L = -0.833 + 0.242A; R 2 = 0.84) and a power function for S. poli-tus (L = 0.825 × A 0.647; R 2 = 0.76). Sufficient S. politus were available to analyze seasonal effects on growth rate; no significant differences were detected. No significant difference in the S. politus growth rate between preservation media was detected for samples collected on September 1, 2004.

Miller E.F.,MBC Applied Environmental science | Pondella II D.J.,Occidental College | Beck D.S.,MBC Applied Environmental science | Herbinson K.T.,ACT Environmental
ICES Journal of Marine Science | Year: 2011

A unique 38-year time-series of power-plant entrapment data collected across ∼170 km of the southern California coastline was examined to describe the decadal-scale trends in common Southern California Bight sciaenid abundance in relation to oceanographic conditions. Adult catches for five of seven species declined at differing rates and severity. Declines of up to 94% were detected in historically common species such as Genyonemus lineatus, whereas historically less abundant species have increased dramatically, e.g. Umbrina roncador (2626%). Over time, the entrapped community became increasingly influenced by species with more southerly distributions, indicated by a significant decline in the average latitudinal midpoint of the community. This shift was significantly related to rising ocean temperature and took place in the early to mid-1980s. The observed species-specific abundance changes in all species except Atractoscion nobilis were significantly correlated with sea surface temperature, nearshore plankton volumetric biomass, G. lineatus or Seriphus politus nearshore larval density, or a combination of these. Patterns in A. nobilis abundance were the most isolated, likely reflecting its standing as an intensively fished species, unlike the other six species evaluated. The consistent relationship with environmental indices strongly supported the notion of a faunal shift driven by bottom-up forcing. © 2011 International Council for the Exploration of the Sea.

Field J.C.,National Oceanic and Atmospheric Administration | MacCall A.D.,National Oceanic and Atmospheric Administration | Ralston S.,National Oceanic and Atmospheric Administration | Love M.S.,University of California at Santa Barbara | Miller E.F.,MBC Applied Environmental science
California Cooperative Oceanic Fisheries Investigations Reports | Year: 2010

Bocaccio (Sebastes paucispinis) has been one of the most important species of rockfish to both commercial and recreational fisheries in California Current waters over the last century. Actions taken to rebuild the stock of bocaccio residing off of California have been responsible for dramatic changes on both commercial and recreational groundfish management and total allowable yields of most groundfish species in California waters over the last decade, including a virtual cessation of commercial and recreational fishing in 2003. In retrospect, it was determined that a strong 1999 year class was moving through the fishery at that time, resulting in high catch rates during a period in which management sought to drastically reduce catch. This results in a paradox, in which rebuilding requires strong year classes, which requires further constraints on fishing during periods in which the condition of the stock seems to be improving. Although this paradox exists for all stocks undergoing rebuilding, it is particularly pronounced for bocaccio as they have among the greatest variability in recruitment observed in any species of West Coast rockfish, as well as very rapid growth and very young age at recruitment to the recreational fishery. Consequently, accurate indices of the strength of incoming year classes both improve stock assessment estimates of future (near term) abundance trends, as well as aid regulators in making management decisions during those infrequent periods of high abundance of young fish. We discuss several indices of recruitment strength based on data on young bocaccio, evaluate their relative performance in the early detection of strong year classes, and consider both the oceanographic factors that may drive recruitment variability, as well as the spatial patterns of recruitment events which may aid in interpreting these indices.

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.

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.

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.

Miller E.F.,MBC Applied Environmental science | Schiff K.,Southern California Coastal Water Research Project
California Cooperative Oceanic Fisheries Investigations Reports | Year: 2012

Despite intense localized monitoring, few regional assessments of demersal fish assemblages are conducted in the Southern California Bight (SCB). The goal of this study was to describe temporal changes in regional-scale SCB demersal fish assemblages (density, biomass, size class) in relation to regional environmental changes (temperature and related climate indices). Nearly 600 small otter trawls were conducted by collaborating agencies between 3 and 200 m depth during the summers of 1994, 1998, 2003, and 2008 under a standardized sampling plan. Summer water temperature at depth between 1950 and 2008 has remained relatively stable although temperatures in 1998 and 2008 were above the long-term mean while the 1994 and 2003 temperatures were at or below the mean. Mean demersal fish density increased each survey between 1994 and 2003 before declining in 2008, while mean biomass increased each survey since 1994 reaching its maximum in 2008. Based on community similarity analyses, the 1998 survey was appreciably different than the other three surveys, with 2003 and 2008 being the most similar. This could be the result of anomalously warm-water conditions recorded during the 1997-98 El Niño and the resultant temporary pole ward expansion of numerous species. Although the sample size was limited to four regional surveys, the best predictors of mean demersal fish density and biomass were the Northern Pacific Gyre Oscillation and the Multivariate El Niño-Southern Oscillation Index. Increasing temperature, or similar patterns in environmental indices, resulted in reduced density and biomass. Furthermore, habitat valuation revealed a trend of increasing value with depth and latitude with the southern inner shelf areas scoring the lowest habitat value. With the addition of more data, regional surveys such as these surveys provide a good foundation on which to analyze changes in demersal fish assemblages.

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.

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.

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