Patterns in the diet of Illex argentinus (Cephalopoda: Ommastrephidae) from the Falkland Islands jigging fishery

Mouat, Beth; Collins, Martin A.; Pompert, J.

doi:10.1016/s0165-7836(01)00229-6

Cited by 34 publications

(28 citation statements)

References 15 publications

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“…These results are consistent with those reported for squids inhabiting the northern region of the species distribution (Ivanovic & Brunetti 1994, Santos & Haimovici 1997, Bazzino & Quiñones 2001 and contrary to those reported for squids of the southern region, where the most consumed prey are pelagic crustaceans (e.g. Themisto gaudichaudii) (Ivanovic & Brunetti 1994, Mouat et al 2001, Ivanovic 2000, Laptikhovsky 2002.…”

Section: Discussionsupporting

confidence: 90%

Section: Discussioncontrasting

confidence: 55%

“…In the present study, 5 species could be identified in the stomach contents of Illex argentinus. The prey spectrum consumed by squids in San Matias Gulf is low when compared with previous studies conducted with individuals from the outer shelf and slope (Ivanovic & Brunetti 1994, Santos & Haimovici 1997, Mouat et al 2001.Illex argentinus is an opportunistic predator, and its diet varies along the continental shelf and slope, depending on the availability of potential prey (Ivanovic & Brunetti 1994). In the San Matias Gulf, individuals of both spawning groups, regardless of size class, fed on the same prey with a predominance of fishes.…”

mentioning

confidence: 74%

“…Argentine shortfin squid Illex argentinus (Castellanos, 1960) is not an exception to this rule and is an important link in the trophic web of the Argentinean shelf community (Angelescu & Prenski 1987, Ivanovic 2000, Santos & Haimovici 2001, KoenAlonso & Yodzis 2005. However, the diet of this species changes among regions along its geographical distribution range (Ivanovic & Brunetti 1994, Santos & Haimovici 1997, Ivanovic 2000, Bazzino & Quiñones 2001, Mouat et. al 2001, Laptikhovsky 2002; thus the role that I. argentinus plays in the trophic web may change among regions as well.…”

Section: Introductionmentioning

confidence: 99%

“…al 2001, Laptikhovsky 2002; thus the role that I. argentinus plays in the trophic web may change among regions as well. At present, all research of I. argentinus diet has been conducted with specimens caught on the outer shelf and slope south of 26°S (Ivanovic & Brunetti 1994, Santos & Haimovici 1997, Bazzino & Quiñones 2001, Mouat et. al 2001, Laptikhovsky 2002, and coastal regions were neglected.…”

Section: Introductionmentioning

confidence: 99%

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Diet of spring and summer spawning groups of Illex argentinus inhabiting coastal waters in San Matias Gulf (northern Patagonia, Argentina)

Crespi-Abril¹,

Trivellini²

2011

Aquat. Biol.

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To study the diet of 2 coastal spawning groups of Illex argentinus, we analyzed the stomach contents of 3645 specimens (10 to 36 cm in mantle length). More than half (58%) of observed stomachs were empty. There were no differences in the prey consumed between specimens of different sex and maturity stages. Additionally, no differences were observed in the diet among individuals belonging to either the summer or spring spawning groups. The most frequent prey item was fishes (0.79 frequency of occurrence), followed by cephalopods (0.18) and lastly by crustaceans (0.09). The seasonal variation of empty stomach frequency and the mean stomach fullness revealed that squids fed more actively in spring and summer and mainly preyed upon small pelagic fishes. KEY WORDS: Illex argentinus · Near-shore waters · Diet · CephalopodsResale or republication not permitted without written consent of the publisher Aquat Biol 14: 99-103, 2011 MATERIALS AND METHODSSamples were obtained with 21 surveys while onboard trawling from vessels which were operating in the San Matias Gulf (42°S, 64.5°W) between June 2005 and October 2007. Tows were conducted during the day with a bottom trawl net (120 mm mesh size) at approx. 4 knots within the deep range, 90 to 150 m. A total of 3645 individuals of both spawning groups (1516 SSG and 2129 SpSG) were collected and were preserved chilled for posterior dissection in the laboratory. During dissection, the stomach of each individual was extracted and supplementary biological information of each specimen was recorded: dorsal mantle length to the nearest cm, sex, and macroscopic maturity condition (Nigmatullin 1989). To analyze the data, maturity stage (I to VII) was grouped into 3 categories as defined by Laptikhovsky & Nigmatullin (1993): immature individuals (stages I and II), physiologically mature individuals (stages III and IV), and functionally mature individuals (stages V, VI and VII).Stomachs were analyzed under 60× magnification, and the hard structures found in the contents were stored and used for prey identification to species level. To determine what the species consumed, identification keys (Clarke 1986, Boschi et al. 1992, Gosztonyi & Kuba 1996, Volpedo & Echeverría 2000 and reference material were used. In the cases of stomachs without hard structures, tissue remains (i.e. muscle, gladius, crystalline, exoskeletons) were used to assign prey into main categories such as fishes, cephalopods or crustaceans. Additionally, for each specimen the stomach fullness (SF) was recorded following the scale proposed by Amaratunga & Durward (1978): 0 = empty, 1 = half full, 2 = full, 3 = distended.A generalized linear model (GLM) was fitted to data (McCullagh & Nelder 1998) to compare the frequency of prey consumed using the maturity condition of individuals, spawning group and sex as covariates. In this model, the dependent variable was the frequency of stomachs corresponding to each category of the covariates and was assumed to follow a Poisson distribution. The function used to lin...

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Section: Discussionsupporting

confidence: 90%

Section: Discussioncontrasting

confidence: 55%

mentioning

confidence: 74%