Life cycles, oceanography and variability: ommastrephid squid in variable oceanographic environments

Anderson, C. I. H.; Rodhouse, P. G.

doi:10.1016/s0165-7836(01)00378-2

Cited by 132 publications

(91 citation statements)

References 31 publications

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“…For example, the high concentration of D. gigas took place in Peru- vian waters with SST between 17 and 22ºC (Waluda et al, 2006). Thus, the result of this study supports the hypothesis that SST is critical in influencing the spatial distributon of D. gigas (Anderson and Rodhouse, 2001;Nigmatullin et al, 2001). The recent catch of D. gigas along the Chilean coast between 2002 and 2005 has been reported to increase (Zúñiga et al, 2008), which is consistent with the report in the waters of 40-45°S and 100-75°W by the Chinese large mid-water trawler targeting jack mackerel (Trachurus murphyi) and the Chinese squid jigging survey from 2006 to 2008.…”

Section: Dietssupporting

confidence: 88%

Fishery biology of the jumbo flying squid <i>Dosidicus gigas</i> off the Exclusive Economic Zone of Chilean waters

Liu¹,

Chen²,

Lu³

et al. 2010

Sci. Mar.

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SUMMARY:The jumbo flying squid Dosidicus gigas is widely distributed in the eastern Pacific Ocean and supports an important fishery. Although many studies have been carried out on the biology of this species, limited biological information is available in the waters outside the Exclusive Economic Zone of Chile (EEZ) (20°S-41°S and 74°30ʹW-84°W). Three surveys were conducted in this area by the Chinese squid jigging vessels during the period from April 2006 to May 2008. The majority of the catch in the survey was from the two areas defined by 37°30ʹ-41°S and 78°30ʹ-80°W and by 25°-30°S and 76°-77°30ʹW. The sex ratio (M: F) of the catch was 1: 2.48. The mean mantle length (ML) was 376 mm for males with a range of 257-721 mm and 388.7 mm for females with a range of 236-837 mm. Two distinguished size classes, medium-and large-sized groups, were identified in this study with the medium-sized group (350-450 mm ML) consisting of 89% of the total catch. The sizes at first sexual maturity were 638 mm ML for females and 565 mm ML for males. This study suggests that all the individuals examined were hatched from March 2007 to February 2008, indicating that D. gigas might spawn all year around with a peak spawning time from November 2007 to January 2008. Most of the stomachs analyzed had food remains. The preys included three major groups: fish (mainly lanternfish), cephalopods and crustaceans, but D. gigas was the dominant species in the stomach contents, showing strong evidence of cannibalism. The information obtained from this study improves our understanding of the fishery biology of D. gigas off Chile.Keywords: Dosidicus gigas, fishery biology, Chile. RESUMEN: Biología pesquera de la pota gigante DosiDicus gigas en aguas exteriores a la Zona Económica Exclusiva de Chile. -La pota gigante Dosidicus gigas está ampliamente distribuida en el océano Pacífico oriental y soporta una pesquería importante. Aunque se han realizado muchos estudios sobre la biología de esta especie, la información existente para aguas externas a la Zona Económica Exclusiva (ZEE) de Chile (20ºS-41ºS y 74º30ʹW-84ºW) es muy limitada. Los barcos poteros chinos realizaron tres campañas en esta área entre abril de 2006 y mayo de 2008. La mayoría de las capturas en esas campañas proceden de dos áreas definidas por las coordenadas 37º31ʹS-41ºS 78º30ʹW-80ºW y 25ºS-30ºS 76ºW-77º30ʹW, respectivamente. La relación sexual (M:H) en las capturas fue de 1:2.48. La longitud media del manto (LM) fue de 376 mm para los machos con un rango que varió entre 257 y 721 mm, y de 388.7 mm para las hembras (236-837 mm). Se diferenciaron dos clases de tamaño: un grupo medio, cuya LM varió entre 350 y 450 mm representando un 89% de la captura total, y un grupo grande. La talla de primera maduración sexual fue de 638 mm para las hembras y de 565 mm para los machos. Este trabajo sugiere que todos los individuos examinados habían nacido entre marzo de 2007 y febrero de 2008, lo cual indica que D. gigas puede frezar durante todo el año, habiendo existido un pico de puesta desde n...

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Section: Dietssupporting

confidence: 88%

Fishery biology of the jumbo flying squid <i>Dosidicus gigas</i> off the Exclusive Economic Zone of Chilean waters

Liu¹,

Chen²,

Lu³

et al. 2010

Sci. Mar.

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“…Such characteristics make cephalopod populations sensitive to environmental fluctuations; thus their abundance tends to fluctuate more than that of long-lived, slow growing species. Migration patterns, population size and geographic distribution of cephalopods are particularly susceptible to changes in oceanographic conditions (Anderson & Rodhouse 2001, Boyle & Rodhouse 2005, Dawe et al 2007, Semmens et al 2007). The jumbo squid Dosidicus gigas (d'Orbigny, 1835) is the most abundant squid in the HCS.…”

Section: Introductionmentioning

confidence: 99%

Genetic diversity and demographic history of Dosidicus gigas (Cephalopoda: Ommastrephidae) in the Humboldt Current System

Ibáñez¹,

Cubillos²,

Tafur³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…Furthermore, our study focussed only on acoustic targets that formed discrete and regular schools, which reduces the likelihood of siphonophores biasing our results because they do not aggregate densely. Although squid, such as Martial hyadesi and Loligo gahi, have been reported around South Georgia, particularly during austral winter (June), these organisms have a distribution that is highly associated with the Antarctic Polar Front and are found predominantly in regions beyond the WCB (Anderson and Rodhouse, 2001;Gonzalez and Rodhouse, 1998;Rodhouse et al, 1996). Ground-truthed acoustic observations also showed that aggregations of squid in the region tended to have a relatively weak acoustic response and exhibit positive S v120-38 kHz backscatter (Goss et al, 2001;), so we advocate that squid were an unlikely source of bias in the study.…”

Section: Target Identificationmentioning

confidence: 99%

School characteristics of mesopelagic fish at South Georgia

Saunders

Fielding

Thorpe

et al. 2013

Deep Sea Research Part I: Oceanographic Research Papers

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In this paper, we describe the variation in myctophid schools characteristics at South Georgia using multi-frequency acoustic data collected annually between November 2007 and January 2012. We studied the relationship between the proximity of land and the distribution and schooling characteristics of myctophid fish. We also examined patterns in schooling behaviour in relation to oceanographic data. Fish schools were identified using a dualfrequency dB identification method (S v120-38 kHz ), where negative S v120-38 kHz is indicative of gas-bearing organisms, such as swimbladdered fish. Available net data were used to provide information on the meosopelagic fish community in the region. School morphometrics (e.g. length, thickness, area) data were extracted and pooled according to their distance from the shore (0-30 km, 30-60 km, 60-90 km, 90-120 km). A total of 578 schools were detected in the survey region and there was high variation in school backscattering strength (NASC), length, height, perimeter, depth and horizontal distribution between surveys, including distinct inter-annual variation in these parameters when surveys were conducted in the same season (2009)(2010)(2011)(2012). Schools were distributed predominantly on-shelf (0-500 m isobaths) during some summer surveys (2007 and 2012) and predominantly off-shelf on others (>500 2 m isobaths; 2009, 2010 and 2011). There was also evidence of bathymetric separation in the horizontal distribution of schools. Schools observed in the late-season in 2008 had the greatest NASC, largest height and the deepest depth distribution. Most schools occurred at depths between ~60-300 m, but they did not occupy the same water masses during each survey. Schools became progressively thinner, shallower and acoustically weaker with increasing distance to land, whilst school length and perimeter increased correspondingly.The change in fish schooling behaviour between environments could be a response to a combination of local predatory threats over short spatial/temporal scales and differences in oceanographic conditions, such as current velocity. The trend could also be evidence of spatial habitat partitioning of myctophids, with different schooling species, or different lifestages, orientating along a bathymetric gradient at South Georgia.

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Life cycles, oceanography and variability: ommastrephid squid in variable oceanographic environments

Cited by 132 publications

References 31 publications

Fishery biology of the jumbo flying squid <i>Dosidicus gigas</i> off the Exclusive Economic Zone of Chilean waters

Fishery biology of the jumbo flying squid <i>Dosidicus gigas</i> off the Exclusive Economic Zone of Chilean waters

Genetic diversity and demographic history of Dosidicus gigas (Cephalopoda: Ommastrephidae) in the Humboldt Current System

School characteristics of mesopelagic fish at South Georgia

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