Upwelling of nutrient-rich, subsurface water sustains high productivity in the ocean's eastern boundary currents. These ecosystems support a rate of fish harvest nearly 100 times the global mean and account for >20% of the world's marine fish catch. Environmental variability is thought to be the major cause of the decadal-scale biomass fluctuations characteristic of fish populations in these regions, but the mechanisms relating atmospheric physics to fish production remain unexplained. Two atmospheric conditions induce different types of upwelling in these ecosystems: coastal, alongshore wind stress, resulting in rapid upwelling (with high vertical velocity, w); and wind-stress curl, resulting in slower upwelling (low w). We show that the level of wind-stress curl has increased and that production of Pacific sardine (Sardinops sagax) varies with wind-stress curl over the past six decades. The extent of isopycnal shoaling, nutricline depth, and chlorophyll concentration in the upper ocean also correlate positively with wind-stress curl. The size structure of plankton assemblages is related to the rate of wind-forced upwelling, and sardine feed efficiently on small plankters generated by slow upwelling. Upwelling rate is a fundamental determinant of the biological structure and production in coastal pelagic ecosystems, and future changes in the magnitude and spatial gradient of wind stress may have important and differing effects on these ecosystems. Understanding of the biological mechanisms relating fisheries production to environmental variability is essential for wise management of marine resources under a changing climate.

/pdf/influence-of-ocean-winds-on-the-pelagic-ecosystem-in-54rbv42m7l.pdf

Influence of ocean winds on the pelagic ecosystem in upwelling regions

Foreword Preface 1. History of international co-operation in research Jurgen Alheit and Andrew Bakun 2. A short scientific history of the fisheries Alec D. Maccall 3. Habitats Dave Checkley, Patricia Ayon, Tim R. Baumgartner, Miguel Bernal, J. C. Coetzee, Robert Emmett, Renato Guevara, Larry Hutching, Leire Ibaibarriaga, Hideaki Nakata, Yoshioki Oozeki, Benjamin Planque, Jake Schweigert, Yorgos Stratoudakis and Carl D. Van der Lingen 4. Variability from scales in marine sediments and other historical records David B. Field, Tim R. Baumgartner, Vicente Ferreira, Dimitri Gutierrez, Hector Lozano-Montes, Renato Salvatteci and Andy Soutar 5. Decadal-scale variability in populations Jurgen Alheit, Claude Roy and Souad Kifani 6. Biophysical models Christophe Lett, Kenneth A. Rose and Bernard A. Megrey 7. Trophic dynamics Carl D. Van der Lingen, Arnaud Bertrand, Antonio Bode, Rick Brodeur, Luis Cubillos, Pepe Espinoza, Kevin Friedland, Susana Garrido, Xabier Irigoien, Todd Miller, Christian Mollman, Ruben Rodriguez Sanchez, Hiroshige Tanaka and Axel Temming 8. Impacts of fishing and climate change explored using trophic models Lynne Shannon, Marta Coll, Sergio Neira, Philippe Cury and Jean-Paul Roux 9. Current trends in the assessment and management of stocks Manuel Barange, Miguel Bernal, Maria Cristina Cergole, Luis A. Cubillos, Carryn L. Cunningham, Georgi M. Daskalov, Jose A. A. de Oliveira, Mark Dickey-Collas, Dave J. Gaughan, Kevin Hill, Larry D. Jacobson, Fritz W. Koster, Jacques Masse, Hiroshi Nishida, Miguel Niquen, Yoshioki Ooozeki, Isabella Palomera, Suzana A. Saccardo, Alberto Santojanni, Rodolfo Serra, Stylios Somarakis, Yorgos Stratoudakis, Andres Uriarte, Carl D. Van der Lingen and Akihiko Yatsu 10. Global production and economics Samuel F. Herrick, Jr., Jerrold G. Norton, Rognvaldur Hannesson, U. Rashid Sumaila, Mahfuzuddin Ahmed and Julio Pena-Torres 11. Human dimensions of the fisheries under global change Rosemary E. Ommer, Astrid C. Jarre, R. Ian Perry, Manuel Barange, Kevern Cochrane and Coleen Moloney 12.Mechanisms of low-frequency fluctuations in anchovy and sardine populations Alec D. MacCall 13. Research challenges in the twenty-first century Andrew Bakun 14. Conjectures on future climate effects on marine ecosystems dominated by small pelagic fish Pierre Freon, Francisco Werner and Francisco Chavez 15. Synthesis and perspective Dave Checkley, Andrew Bakun, Manuel A. Barange, Leonardo R. Castro, Pierre Freon, Renato Guevara-Carrasco, Samuel F. Herrick, Jr., Alec D. MacCall, Rosemary Ommer, Yoshioki Oozeki, Claude Roy, Lynne Shannon and Carl D. van der Lingen Index.

/pdf/climate-change-and-small-pelagic-fish-2vxlat8boo.pdf

Climate Change and Small Pelagic Fish

During the 1930s and 1940s, Pacific sardines (Sardinops sagax) supported an important fishery in Pacific Northwest waters, but after their population crashed in the mid-1950s, they were rarely observed in this region. Starting in the mid-1990s, sardines resumed migrating into Northwest waters to spawn and feed. Pacific sardines now support a relatively large purse seine fishery centered off the Columbia River. From 1994 to 1998, we identified the abundance and distribution of Pacific sardine eggs and larvae in Northwest waters. The highest egg densities were observed in June 1996. During all years, eggs were associated with surface temperatures between 14˚ and 15˚C. From 1998 to 2004, surface-trawl surveys, primarily on the continental shelf, identified the temporal and spatial distribution and abundance patterns of juvenile and adult Pacific sardines. Adult sardines generally do not over-winter off the Northwest, but migrate north from California in the spring (May‐June) when surface temperatures exceed 12˚C. However, juvenile sardines over-winter in nearshore coastal waters. During most years, few 0-age juveniles were captured, indicating relatively poor spawning success; however, high densities of 0-age sardines were observed in fall of 2003 and 2004, indicating successful spawning. During the summer, sardines are most abundant on the shelf in cool ( 30 S) coastal waters, with their highest densities occurring in northern Oregon/Washington waters. Sardines are non-selective planktonic filter feeders; prey include copepods, euphausiids, and phytoplankton. Sardines are important prey of Northwest fishes, such as sharks, salmon, Pacific hake (Merluccius productus), and jack mackerel (Trachurus symmetricus).

https://www.calcofi.org/publications/calcofireports/v46/Vol_46_Emmett_et_al_Pacific_Sardine.pdf

Pacific sardine (sardinops sagax ) abundance, distribution, and ecological relationships in the pacific northwest

Contrasting spawning temperature optima: Why are anchovy and sardine regime shifts synchronous across the North Pacific?

Zwolinski, J. P., Emmett, R. L., and Demer, D. A. 2011. Predicting habitat to optimize sampling of Pacific sardine (Sardinops sagax). – ICES Journal of Marine Science, 68: 867–879.More than 40 years after the collapse of the fishery for Pacific sardine, a renewed fishery has emerged off the west coasts of the United States and Canada. The daily egg production method (DEPM) and acoustic-trawl surveys are performed annually and, to minimize the uncertainties in the estimates, sampling effort needs to be allocated optimally. Here, based on a 12-year dataset including the presence/absence of sardine eggs and concomitant remotely sensed oceanographic variables, a probabilistic generalized additive model is developed to predict spatio-temporal distributions of habitat for the northern stock of Pacific sardine in the California Current. Significant relationships are identified between eggs and sea surface temperature, chlorophyll a concentration, and the gradient of sea surface altitude. The model accurately predicts the habitat and seasonal migration pattern of sardine, irrespective of spawning condition. The predictions of potential habitat are validated extensively by fishery landings and net-sample data from the northeast Pacific. The predicted habitat can be used to optimize the time and location of the DEPM, acoustic-trawl, and aerial surveys of sardine. The method developed and illustrated may be applicable too to studies of other stocks of sardine and other epipelagic fish in other eastern boundary, upwelling regions.

/pdf/predicting-habitat-to-optimize-sampling-of-pacific-sardine-50trfxna2n.pdf

Predicting habitat to optimize sampling of Pacific sardine (Sardinops sagax)

Recent work has examined the structure of stocks, races, or subpopulations in the recovering Pacific sardine (Sardinops sagax) biomass of the northeast Pacific Ocean. Individual fish characteristics do not clearly indicate the geographic origin of birth, but collections of sardines from different areas show some heterogeneity in growth rate, time of birth and recruitment, blood type, and number of vertebrae. Even when heterogeneity is in question, precautionary management principles, which reduce the risk of overfishing, should support management of stocks of fish in different areas as independent stocks. The sardines of the northeast Pacific have been estimated to have up to three subpopulations based on tagging, size-at-age, isolated spawning centers, blood groups, vertebral column counts, estimated natural mortality rate, or bimodal seasons of recruitment. Spawning centers are thought to occur off the Gulf of California (GOCAL), Baja California Sur inshore (BSI) and Central California offshore (CCO). Cursory genetic examinations of sardines from these areas neither support nor refute these divisions. Genetic analysis of S. sagax from four far-flung sardine habitat sectors of the Pacific basin can be described as “shallow,” meaning the separation of all the species in the Pacific is relatively recent. However, on the time scale of fisheries management, decades, the separation of the two stocks on the Pacific coast, BSI and CCO, appears chronic in that the collapse of the northern stock did not stimulate an apparent replacement from the southern stock in decades. Therefore, it would be prudent to institute separate management measures that define the boundary between GOCAL and BSI and the boundary between BSI and CCO regardless of the genetic or habitat basis for stock separation. Three datarich bases for describing the two stocks’ modern isolation should be used to design careful studies of representative samples of sardines at the boundaries between the stocks for devising the most practical method for allocating catches among the neighboring stocks. This paper reviews existing data to see which might be applied to a precautionary approach to managing the revived Pacific sardine fisheries. It also examines what advances in our knowledge of these stocks and the methods used to assess them may be required to ensure an adequate spawning biomass and yield of the sardine fisheries for the northeast Pacific stock(s).

http://www.calcofi.org/publications/calcofireports/v46/Vol_46_Smith_History_Of_Subpopulation_Structure.pdf

A history of proposals for subpopulation structure in the pacific sardine (sardinops sagax) population off western north america

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Paul E. Smith

Author Tools

Chat about Author

Papers

A history of proposals for subpopulation structure in the pacific sardine (sardinops sagax) population off western north america