Yoshioki Oozeki

Climate change and small pelagic fish

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.

Growth and Survival of Pacific Saury Cololabis saira in the Kuroshio-Oyashio Transitional Waters

Growth and mortality rates of larval and early juvenile Pacific saury Cololabis saira were estimated for spring and autumn spawning seasons in the Kuroshio-Oyashio transitional waters and for winter spawning season in the Kuroshio waters in 9 years from 1990–1998, based on quantitative fish sampling and otolith daily ring readings. Growth and mortality rates were more variable in the Kuroshio-Oyashio transitional waters than in the Kuroshio waters. The estimated production of 40-mm preschooling juveniles was a positive function of larval production in the hatching length class (5.9–9.9 mm) in the Kuroshio waters. In the Kuroshio-Oyashio transitional waters, rather than larval production in the hatching length class, cumulative survival through the larval and early juvenile stages determined the juvenile production. Variable growth and survival rates of saury observed in the transitional waters seem to be associated with large environmental variability in the waters, including shifts of the Kuroshio and Oyashio fronts and development of streamers and eddies between the fronts.

Growth effect on the otolith and somatic size relationship in Japanese anchovy and sardine larvae

Relationships between otolith and somatic sizes were examined for Japanese anchovy Engraulis japonicus and sardine Sardinops melanostictus larvae collected broadly in the western North Pacific, based on a substantial data set derived from a previous paper. Allometric formulae showed close fits to the relationships between otolith radius and standard length, and the formulae differed between anchovy and sardine larvae. Despite the high correlations, the effect of somatic growth rate on the otolith and somatic size relationship (the ‘growth effect’) was significantly detected for both anchovy and sardine larvae. Slower growing larvae tended to have larger otoliths than faster growing conspecifics at the same somatic size. This growth effect was more obvious for sardine larvae than for anchovy larvae, probably because of their differential responses of somatic growth to temperature shifts. The growth effect could lead to the possibility of biases in the backcalculation and size estimation processes. As the growth effect is considered to be a general phenomenon and its extent to be species-specific, the relationship between otolith and somatic size and its uncoupling should be scrutinized before application of techniques based on the otolith and somatic size correlation.

Predation dynamics of mackerel on larval and juvenile anchovy: is capture success linked to prey condition?

We tested whether the predation dynamics of chub mackerel Scomber japonicus and spotted mackerel S. australasicus on young anchovy Engraulis japonicus relates to individual growth characteristics of the prey and could account for the growth-selective survival predicted by recruitment hypotheses. Juvenile and adult mackerel were sampled along with their young anchovy prey field in 2004 (juvenile mackerel and larval anchovy) and 2005 (adult mackerel and juvenile anchovy) off the Pacific coast of Honshu, Japan. The recent 5-day mean growth rate of larval and juvenile survivors and prey found in the stomach of mackerel was estimated from the otolith microstructure. No significant difference was found between the recent growth of larval or juvenile survivors and that of preyed individuals. We conclude that despite a relatively small body size, the high activity level and predation skills displayed by mackerel prevent fast-growing larvae and early juveniles from benefitting in terms of the expected survival advantage over slow-growers. Hence, growth-selective predation mortality of larval fish would depend on the feeding ecology of the predator rather than predator size. Selection for fast growth is more likely to occur under predation pressure from invertebrate organisms and small pelagic fish specialized on zooplankton, such as herring and anchovy.

Effective time closures: quantifying the conservation benefits of input control for the Pacific chub mackerel fishery

Restricting human access to a specific wildlife species, community, or ecosystem, i.e., input control, is one of the most popular tools to control human impacts for natural resource management and wildlife conservation. However, quantitative evaluations of input control are generally difficult, because it is unclear how much human impacts can actually be reduced by the control. We present a model framework to quantify the effectiveness of input control using day closures to reduce actual fishing impact by considering the observed fishery dynamics. The model framework was applied to the management of the Pacific stock of the chub mackerel (Scomber japonicus) fishery, in which fishing was suspended for one day following any day when the total mackerel catch exceeded a threshold level. We evaluated the management measure according to the following steps: (1) we fitted the daily observed catch and fishing effort data to a generalized linear model (GLM) or generalized autoregressive state-space model (GASSM), (2) we conducted population dynamics simulations based on annual catches randomly generated from the parameters estimated in the first step, (3) we quantified the effectiveness of day closures by comparing the results of two simulation scenarios with and without day closures, and (4) we conducted additional simulations based on different sets of explanatory variables and statistical models (sensitivity analysis). In the first step, we found that the GASSM explained the observed data far better than the simple GLM. The model parameterized with the estimates from the GASSM demonstrated that the day closures implemented from 2004 to 2009 would have decreased exploitation fractions by ~10% every year and increased the 2009 stock biomass by 37-46% (median), relative to the values without day closures. The sensitivity analysis revealed that the effectiveness of day closures was particularly influenced by autoregressive processes in the fishery data and by positive relationships between fishing effort and total biomass. Those results indicated the importance of human behavioral dynamics under input control in quantifying the conservation benefit of natural resource management and the applicability of our model framework to the evaluation of the input controls that are actually implemented.

Where are the eggs of the Pacific saury,Cololabis saira?

T he Pacific saury, Cololabis saira (Brevoort), is one of the most important pelagic species for Japanese fisheries. The species produces a large number of larvae, up to 3000 individ./(km 2 day) year around in the Northwestern Pacific Ocean (Watanabe and Lo, 1989), the eggs usually being attached by filaments to floating objects such as drifting seaweed (e.g., Sargassum spp.); with unattached eggs being rarely observed (Konishi, 1981; Shyojima, 1981). However, it has been pointed out that the amount of floating material necessary to support the estimated amount of saury eggs in the ocean surface layer is not sufficient to explain the observed abundance of saury larvae (Fukushima, 1981). The present study attempts to clarify the depth layer where unattached eggs of Pacific saury may be distributed. The specific gravity of saury eggs was measured for various developmental stages. Using these estimates of specific gravity, the fate of unattached saury eggs was predicted.

Revisiting morphological identification of Japanese jack mackerel Trachurus japonicus eggs preserved in formalin

Since formalin-preserved eggs of Japanese jack mackerel Trachurus japonicus have been considered difficult to identify, egg abundance of this species has not been estimated, and subsequently information on their spawning habitat is limited. The present study provides a practical identification of Japanese jack mackerel eggs from formalin-preserved samples based on morphological characteristics with validations through DNA sequencing and a rearing experiment. Eggs obtained by artificial fertilization from mature adults were reared in the laboratory, and developmental changes of morphological characteristics in the formalin-preserved samples were examined. The morphological descriptions were detailed to identify jack mackerel eggs from field-captured egg samples preserved in formalin. Moreover, the identification was validated through DNA sequencing and a rearing experiment. Overall, the diagnostic characteristic for identification was the egg diameter and the segmentation of the yolk, which was maintained in formalin-preserved samples even long after fixation. The presented morphological description with its developmental changes for formalin-preserved eggs is anticipated to promote stock assessments and biological studies for jack mackerel based on the egg and larval surveys.

Climate Change and Small Pelagic Fish: Index

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.

Climate Change and Small Pelagic Fish: Contents

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.