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13 resultados encontrados para: AUTOR: Gilly, William F.
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1.
Artículo
Trophic ecology of humboldt squid, dosidicus gigas, in conjunction with body size and climatic variability in the Gulf of California, Mexico
Portner, Elan J. (autor) ; Markaida Aburto, Unai (autor) ; Robinson, Carlos J. (autor) ; Gilly, William F. (autor) ;
Disponible en línea
Contenido en: Limnology and Oceanography Volumen 65 (2020), p. 732-748 ISSN: 1939-5590
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Over the past two decades, the Gulf of California (GOC) has experienced three strong El Niño events (1997–1998, 2009–2010, and 2015–2016), each of which was followed by a drastic reduction in mantle length of mature Humboldt squid, Dosidicus gigas (from >60 cm to <20 cm). However, it is unclear how the oceano-graphic changes associated with strong El Niño events affected the midwater organisms on which D. gigas feed, limiting our ability to assess the relative importance of temperature and food availability in the phenotypic response of D. gigasto environmental variability. We quantified the diet of D. gigas in the GOC before, during, and following the past three El Niño events and found that although its diet varied little across a large range of body sizes (8–85 cm), significant and predictable diet variability was observed with respect to sea surface temperature and chlorophyll-a concentration. Consumption of large numbers of relatively small, high calorie prey inboth relatively cool (anchovies) and relatively warm, productive conditions (myctophids) is likely necessary to support growth to large body sizes before maturation. When warm, unproductive conditions prevailed in the GOC, only small squid were present and had diets dominated by euphausiids and pteropods, prey with relatively low caloric value. Using a time series of diet data, this work provides unique insights into the response of a midwater forage community to oceanographic variability and the effects of environmental variability on thetrophic ecology of an oceanic predator.


2.
- Artículo con arbitraje
Cephalopods of Pacific Latin America
Markaida Aburto, Unai ; Gilly, William F. (coaut.) ;
Contenido en: Fisheries Research Vol. 173, Part2 (January 2016), p. 113–121 ISSN: 0165-7836
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Cephalopod fisheries have experienced outstanding growth in Latin America during the last quartercentury, increasing from 0.5% to 7% of total Latin American landings since 1990. Its waters account todayfor a third of world cephalopod catches, with about two-thirds of this total being landed by Latin American countries and the remainder by East Asian countries. The ommastrephid squids Dosidicus gigas and Illexargentinus have led catches worldwide, while Doryteuthis gahi is the most important loliginid. Mexico,Peru, Chile, Argentina and the Falkland Islands (Malvinas) account for 98% of landings in the region.Pacific waters account for 60% of cephalopod landings in Latin America. Mexico, Peru and Chile accountfor virtually all landings from the Pacific. This has been largely achieved through switching the targets ofnational fishing fleets to squid. There are a variety of directed fisheries for octopus, some of which raiseconcerns about sustainability. Most landings are exported to East Asia and Europe, but local cephalopodsupply has increased. Aquaculture research on octopus in Chile is experiencing a mayor advance with international impact. Cephalopod research in Latin America is progressing in response developments in the fishing industry, especially in Mexico, Peru, and Chile. Nevertheless, cephalopod consumption is still relatively low andfisheries in these countries all depend strongly on foreign markets. In the smaller countries of Central America, as well as Colombia and Ecuador, cephalopods remain negligible as a marine resource.


3.
- Artículo con arbitraje
Prolonged decline of jumbo squid (Dosidicus gigas) landings in the Gulf of California is associated with chronically low wind stress and decreased chlorophyll a after El Niño 2009–2010
Robinson, Carlos J. ; Gómez Gutiérrez, Jaime (coaut.) ; Markaida Aburto, Unai (coaut.) ; Gilly, William F. (coaut.) ;
Contenido en: Fisheries Research Vol. 173, Part 2 (January 2016), p. 128–138 ISSN: 0165-7836
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Dosidicus gigas (jumbo or Humboldt squid) is an ecologically relevant predator in the Gulf of California, Mexico, where it supports an economically valuable fishery. The commercial jumbo squid fishery in the Gulf declined steeply after an El Niño event in 2009–2010, and subsequent landings have remained at historically low levels in the relevant squid fishing centers (Guaymas, Sonora, and Santa Rosalía, Baja California Sur). In this paper, we examined wind speed and chlorophyll a concentrations on the jumbo squid fishing grounds as factors that would be expected to be relevant to this prolonged period of low landings. Analysis from local weather stations, remote sensing, and fishery data showed that low jumbo squid landings from 2010 to 2015 occurred during a period of abnormally weak winter/spring winds and extremely low chlorophyll a concentrations off the East Guaymas Basin. Results indicate that the squid fishing area in the Guaymas region has been chronically impoverished during this period, and that this area may no longer be a productive habitat for jumbo squid. In response to this decreased productivity, size-at-maturity of jumbo squid showed a drastic decrease over the same period. Results are compared with the effect of El Niño 1997–1998 on the jumbo squid fishery and size-at-maturity of this species in the Gulf of California. The key difference between the recovery phases for El Niño 1997–1998 versus El Niño 2009–2010 was the anomalously low wind intensity as measured in the Guaymas fishing area after 2009.


4.
- Capítulo de libro con arbitraje
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Dosidicus gigas, humboldt squid
Rui, Rosa ; Yamashiro, Carmen (coaut.) ; Markaida Aburto, Unai (coaut.) ; Rodhouse, Paul G. K. (coaut.) ; Waluda, Claire M. (coaut.) ; Salinas Zavala, César Augusto (coaut.) ; Keyl, Friedemann (coaut.) ; O´Dor, Ron (coaut.) ; Stewart, Julia S. (coaut.) ; Gilly, William F. (coaut.) ;
Contenido en: Advances in squid biology, ecology and fisheries: myopsid squids New York : Nova Science Publishers, 2013 p. 169-206 ISBN:1-62808331X, 978-1628083316
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Dosidicus gigas (Humboldt or jumbo squid) (Orbigny, 1835) is the largest ommastrephid squid, reaching up to 1.2m mantle length and 65kg in weight. This pelagic squid is endemic to the eastern Pacific Ocean and is particularly abundant in the highly productive waters of the California and Humboldt Current systems, and the Costa Rica Dome upwelling region. The intra-specific population structure of D. gigas is complex, since this species quickly responds to environmental variability driven by El Niño and LaNiña events in both current systems by rapidly changing its biological characteristics, such as somatic and reproductive investment. Oocyte development is asynchronous and the potential fecundity averages around 18–21 million oocytes; the maximum value estimated (32 million oocytes) is the largest ever recorded for any cephalopod so far. Hatching occurs between 6 to 9 days after fertilization at 18°C, but temperatures below 15°C and above 25°C do not allow complete embryonic development. D. gigas passes through a posthatching paralarval stage called the rhynchoteuthion and during this stage the two tentacles are fused into a well-developed proboscis. During the paralarval and subsequent juvenile stages Humboldt squid have a monthly growth rate of up to 80 mm in mantle length, and grow up 60 mm per month in the later stages. This is the highest growth rate reported for any cephalopod species, and enables this species to reach the reported maximum mantle lengths in a short lifespan (12 to 24 months). Although the lack of population structure across its large range suggests a high level of gene flow and substantial horizontal migration, specific migratory pathways in the Pacific Ocean have not yet been demonstrated. Long-distance migration is an important element in the lifehistory of Humboldt squid and may be associated with differential growth rates and size and at full maturity.

The recent poleward range expansion of D. gigasis likely associated with warmer periods following El Niño/La Niña events, an ongoing expansion of the oxygen minimum zone (OMZ) in the Eastern Pacific, and changing ecosystem interactions including food availability, competition and predation. Humboldt squid feed primarily on small mesopelagic (midwater) fishes, crustaceans, and cephalopods as well as commercially important coastal fishes and squid in the recently expanded range. Typical daily behavior involves vertical migrations from near-surface waters at nighttime to mesopelagic depths above or within the OMZ during the daytime. Whereas the OMZ restricts the depth distribution of many competing vertebrate predators to the upper surface layers due to limited hypoxia tolerance, D. gigas circumvents similar restrictions via metabolic suppression. In addition to its critical role both as prey and predator in the eastern Pacific, D. gigas is an economically important species and the target of what has recently become the world’s largest invertebrate fishery.


5.
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Extreme plasticity in life-history strategy allows a migratory predator (jumbo squid) to cope with a changing climate
Gilly, William F. ; Hoving, Henk-Jan T. (coaut.) ; Markaida Aburto, Unai (coaut.) ; Benoit Bird, Kelly J. (coaut.) ; Brown, Zachary W. (coaut.) ; Daniel, Patrick (coaut.) ; Fieldk, John C. (coaut.) ; Parassenti, Li Z. (coaut.) ; Liu, Bilin (coaut.) ; Campos, Bernardita (coaut.) ;
Contenido en: Global Change Biology Vol. 19, no. 7 (July 2013), p. 2089–2103 ISSN: 1365-2486
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Resumen en: Inglés |
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Dosidicus gigas (jumbo or Humboldt squid) is a semelparous, major predator of the eastern Pacific that is ecologically and commercially important. In the Gulf of California, these animals mature at large size (>55 cm mantle length) in 1–1.5 years and have supported a major commercial fishery in the Guaymas Basin during the last 20 years. An El Niño event in 2009–2010, was accompanied by a collapse of this fishery, and squid in the region showed major changes in the distribution and life-history strategy. Large squid abandoned seasonal coastal-shelf habitats in 2010 and instead were found in the Salsipuedes Basin to the north, an area buffered from the effects of El Niño by tidal upwelling and a well-mixed water column. The commercial fishery also relocated to this region. Although large squid were not found in the Guaymas Basin from 2010 to 2012, small squid were abundant and matured at an unusually small mantle-length (<30 cm) and young age (approximately 6 months). Juvenile squid thus appeared to respond to El Niño with an alternative life-history trajectory in which gigantism and high fecundity in normally productive coastal-shelf habitats were traded for accelerated reproduction at small size in an offshore environment. Both small and large mature squid, were present in the Salsipuedes Basin during 2011, indicating that both life- history strategies can coexist. Hydro-acoustic data, reveal that squid biomass in this study area nearly doubled between 2010 and 2011, primarily due to a large increase in small squid that were not susceptible to the fishery. Such a climate-driven switch in size-at-maturity may allow D. gigas to rapidly adapt to and cope with El Niño. This ability is likely to be an important factor in conjunction with longerterm climate-change and the potential ecological impacts of this invasive predator on marine ecosystems.


6.
- Artículo con arbitraje
Behavioral ecology of jumbo squid (Dosidicus gigas) in relation to oxygen minimum zones
Stewart, Julia S. ; Fieldb, John C. (coaut.) ; Markaida Aburto, Unai (coaut.) ; Gilly, William F. (coaut.) ;
Contenido en: Deep Sea Research Part II: Topical Studies in Oceanography doi.org/10.1016/j.dsr2.2012.06.005 (28 June 2012), p. 1-12 ISSN: 0967-0645
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Habitat utilization, behavior and food habits of the jumbo or Humboldt squid, Dosidicusgigas, were compared between an area recently inhabited in the northern California Current System (CCS) and a historically established area of residence in the Gulf of California (GOC). Low dissolved oxygen concentrations at midwater depths define the oxygenminimum zone (OMZ), an important environmental feature in both areas. We analyzed vertical diving behavior and diet of D. gigas and hydrographic properties of the water column to ascertain the extent to which squid utilized the OMZ in the two areas. The upper boundary of the OMZ has been shoaling in recent decades in the CCS, and this phenomenon has been proposed to vertically compress the pelagic environment inhabited by aerobic predators. A shoaling OMZ will also bring mesopelagic communities into a depth range with more illumination during daytime, making these organisms more vulnerable to predation by visual predators (i.e. jumbosquid). Because the OMZ in the GOC is considerably shallower than in the CCS, our study provides insight into the behavioral plasticity of jumbosquid and how they may respond to a shoaling OMZ in the CCS. We propose that shoaling OMZs are likely to be favorable to jumbosquid and could be a key indirect factor behind the recent range expansion of this highly migratory predator.


7.
Artículo
Horizontal movements, vertical-habitat utilization and diet of the jumbo squid (Dosidicus gigas) in the Pacific Ocean off Baja California Sur, Mexico
Bazzino, Gastón ; Gilly, William F. (coaut.) ; Markaida Aburto, Unai (coaut.) ; Salinas Zavala, César Augusto (coaut.) ; Ramos Castillejos, Jorge (coaut.) ;
Contenido en: Progress in Oceanography Vol. 86, no. 1-2 (July-August 2010), p. 59-71 ISSN: 0079-6611
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We deployed four pop-up archival-transmitting (PAT) tags on jumbo squid (Dosidicus gigas) collected in the Pacific Ocean off the main entrance to Magdalena Bay on the Baja California peninsula in June 2005. This is the first successful deployment of PAT tags on jumbo squid in an area outside the Gulf of California. Summary data were obtained through the ARGOS satellite system for three of the tags; the fourth tag was physically recovered. All of the tagged squid tended to remain on the shallow continental shelf for several days after tagging and then moved offshore into deeper water. Three of the four squid appeared to migrate in a general southerly direction while the fourth remained offshore of Magdalena Bay. All of the squid spent most daylight hours at depths that were associated with the hypoxic oxygen minimum layer, and at night they spent a majority of time in the upper 50 m of the water column. Stomach content analysis and tag temperature–depth data during the first days after tagging revealed that the squid were feeding on pelagic red crabs (Pleuroncodes planipes) and several larger, neritic fishes over the continental shelf off Magdalena Bay during a seasonal nearshore upwelling. Comparison of our results with those previously collected in the Gulf of California reveal that Dosidicus gigas can vary its behavior and diet to suit local environmental conditions. This adaptability is likely to be an important factor in the ability of D. gigas to invade and colonize new areas.


8.
- Artículo con arbitraje
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Dosidicus gigas and Sthenoteuthis oualaniensis (Teuthoidea: Ommastrephidae: Ommastrephinae) are abundant, ecologically important squid that co-occur in the eastern tropical Pacific. Little is known about the genetic basis of population structure in either species, although the presence of 2 species within S. oualaniensis has been suggested. We report here on a comparative population genetic study of D. gigas and S. oualaniensis using the mitochondrial marker NADH dehydrogenase subunit 2. Despite the high potential for dispersal in these active swimmers, both species exhibit a distinct biogeographic break at 5 to 6° N. S. oualaniensis contains multiple deeply divergent, geographically segregated clades, whereas D. gigas shows only mild divergence between northern and southern hemisphere populations. We suggest that dispersal and genetic mixing across the eastern tropical Pacific may be impeded by both oceanographic and ecological factors.


9.
Artículo
Food and feeding of jumbo squid Dosidicus gigas in the central Gulf of California during 2005-2007
Markaida Aburto, Unai ; Gilly, William F. (coaut.) ; Salinas Zavala, César Augusto (coaut.) ; Rosas Luis, Rigoberto (coaut.) ; Booth, J. T. Ashley (coaut.) ;
Contenido en: California Cooperative Oceanic Fisheries Investigations Reports Vol. 49 (2008), 90-103 ISSN: 0575-3317

10.
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Perspectives on dosidicus gigas in a changing world
Gilly, William F. (autor) ; Markaida Aburto, Unai (autor) ;
Disponible en línea
Contenido en: The role of squid in open ocean ecosystems / Robert J. Olson, Jock W. Young (Eds.) Honolulu, Hawaii, United States : Report of a GLOBEC-CLIOTOP/PFRP workshop, 2006 p. 81-90
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