Dosidicus gigas (Humboldt/Jumbo Squid)

GPO87

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A squid that hardly needs introduction, Dosidicus gigas (aka. the Humboldt Squid aka. jumbo squid aka diablo rojo, is the only member of the genus Dosidicus.



The Humbolt is well know for its aggresive attitude, as well as a behavior known as "flashing". Flashing is a sudden change in color between red and white skin tones, by the quick contraction of chromatophores.

The range of Humbolt Squid were commonly thought to exist primarily in the tropical Pacific. However, in recent years, that distribution has expanded along the entire Coastline of North and South America.

Info at: http://tolweb.org/Dosidicus/19945
 

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DWhatley

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Dosidicus Research Papers

Extreme Plasticity in Life‐History Strategy Allows a Migratory Predator (Jumbo Squid) to Cope With a Changing Climate
HJ Hoving, WF Gilly, U Markaida, KJ Benoit‐Bird… - Global Change Biology, 2013
Full article freely available without subscription

Abstract

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 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 2010-2012, small squid were abundant and matured at an unusually small mantle-length (
 

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Maturation, Age, and Growth Estimation of the Jumbo Squid Dosidicus gigas (Cephalopoda: Ommastrephidae) in the Central Region of the Gulf of California

Casimiro Quiñonez Velázquez , Agustín Hernández Herrera , Iván Velázquez-Abunader and Nicolas Filauri Valencia 2013

Full article requires subscription to BioOne


ABSTRACT In this study, the statolith microstructure of the jumbo squid Dosidicus gigas was used to determine age, individual growth, and changes in sexual maturity off the west coast of the central region of the Gulf of California during 2000 and 2002. The number of individuals sampled was 3,369 with a sex ratio of 1.8:1 (female to male). The size at first maturity (ML50%) in males varied between 46 cm and 56 cm, which was less than that seen in females (76–79 cm). The age of 251 squid was analyzed, and the growth of each sex was described by fitting the Gompertz and logistic models to the age-mantle length (ML) data. The Gompertz model best described the growth of the jumbo squid, and no significant differences were detected between sexes (ARSS, F = 0.73, P = 0.54). The parameters estimated for the combined data were ML∞ = 143.3 cm and g (growth coefficient at inflection point) = 0.004/y and t[SUB]0[/SUB] (age at inflection point) = 259.5 days. From the hatch date frequency distribution, a permanent incorporation of small individuals (ML,
 
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DWhatley

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Comprehensive Model of Jumbo Squid Dosidicus gigas Trophic Ecology in the Northern Humboldt Current System
Ana Alegre,Frédéric Ménard,Ricardo Tafur,Pepe Espinoza,Juan Argüelles,Víctor Maehara,Oswaldo Flores,Monique Simier,Arnaud Bertrand
2014 (Full paper)

Abstract
The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?). Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters.
 

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Trace element concentrations in the top predator jumbo squid (Dosidicus gigas) from the Gulf of California Joana Raimundo, Carlos Vale,
Rui Rosa 2013 (subscription)


Abstract
Jumbo (or Humboldt) squid, Dosidicus gigas, is a large jet-propelled top oceanic predator off the Eastern Pacific. The present study reports, for the first time, concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd and Pb in gills, mantle and digestive gland of this powerful pelagic squid in the Gulf of California. Zinc and Cu were the most abundant elements. All elements, with the exception of As, were largely stored in digestive gland; particularly Cd that reached concentrations between 57 and 509 µg g−1. Significant relationships between tissues were found for Co (digestive gland–gills), As (gills–mantle) and Cd (digestive gland–mantle). Proportionality of Cd concentrations between mantle and digestive gland suggested that detoxification capacity by digestive gland was insufficient to avoid the transfer of this element to mantle and other tissues. Nonetheless, Cd concentrations in the mantle were always below the regulatory limit and, therefore lack of constraints for human consumption. On the basis of the fishery landings, one may estimate that up to 1 t of Cd can be annually removed by jumbo squid fisheries.

(dwhatley)It would seem removing a ton of Cadmium from the ocean each year may not be a bad thing.
 

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REPRODUCTION AND EARLY LIFE OF THE HUMBOLDT SQUID Danielle Joy Staaf (@Danna ) 2010 (full pdf)

A little Humboldt side reading if you are so inclined :sagrin:

Abstract
Dosidicus gigas, the Humboldt squid, is endemic to the eastern Pacific, and its range has been expanding poleward in recent years. It is a voracious predator of small fish and invertebrates and prominent prey for large fish and mammals, including humans. Very little is known about Humboldt squid reproduction, development, and early life stages. To study the behavior, including dispersal capabilities, of paralarval D. gigas, I analyzed video of animals swimming in the laboratory, and determined that paralarvae are active swimmers that engage in hop-and-sink behavior. Control of the mantle aperture allows them to engage in slow swimming, in which water is leaked through the mantle aperture, and fast jetting, in which the mantle aperture is tightly
closed and all water is expelled through the siphon—as is typical of adult jetting. A theoretical model of squid swimming was built to study the importance of aperture control during the jet cycle. This model predicts that active reduction of the aperture during jetting increases hydrodynamic efficiency, and that squid of large sizes can constrain the risk of embolism by increasing aperture size and decreasing jet frequency to values comparable to empirical measurements. Connectivity among populations of D. gigas throughout the range of this species was assessed with a population genetic approach, in which D. gigas was compared to the co-occurring squid Sthenoteuthis oualaniensis. In D. gigas, only two weakly differentiated populations were evident, with a biogeographic break at 5-6° N. I uncovered four deeply divergent clades in S. oualaniensis, including one which aligns with previous descriptions in the literature of Sthenoteuthis sp. nov. Breaks between clades of S. oualaniensis also occurred at 5-6° N. Range overlap between these two species occurs in the eastern tropical Pacific (ETP), a region both are believed to use as spawning grounds. I looked for paralarvae of D. gigas and S. oualaniensis in surface and subsurface net tows taken in the ETP from 1998 to 2006, and found that abundance was much greater in surface than subsurface tows. I then used a Generalized Linear Model approach to assess the importance of in situ oceanographic variables as predictors of paralarval incidence. ivSea surface temperature was found to be a strong predictor of incidence in both surface and subsurface tows, with the probability of paralarval capture rising
monotonically from near zero at 15 °C to 0.9 at 30 °C. The apparent lack of paralarvae at surface temperatures below 15 °C raises a question of whether D. gigas can spawn in the temperate and even subpolar waters of its expanded range. I conducted in vitro fertilization studies and found the optimal temperature range for successful laboratory development of D. gigas is 15-25° C.
 

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Isolation and characterization of microsatellites for jumbo squid Dosidicus gigas (Ommastrephidae)
ANA M. MILLÁN-MÁRQUEZ1, CÉSAR SALINAS-ZAVALA, PEDRO CRUZ1 and DEVON E. PEARSE 2014 (pdf)

The aim of this study was to isolate and characterize microsatellite markers in D. gigas for later use in population genetic studies. We describe nine polymorphic microsatellites, although most of them have a deficit of heterozygotes apparently caused by a high frequency of null alleles.
 

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Advances in Squid Biology, Ecology and Fisheries: Myopsid Squids. p. 169-206.

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\U+2013\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 18ÀC, but temperatures below 15ÀC and above 25ÀC 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\U+2019\s largest invertebrate fishery.
 

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