scholarly journals Feeding ecology of broadbill swordfish (Xiphias gladius) in the California Current

2021 ◽  
Author(s):  
Antonella Preti ◽  
Stephen M. Stohs ◽  
Gerard T. DiNardo ◽  
Camilo Saavedra ◽  
Ken MacKenzie ◽  
...  
Keyword(s):  
Feeding Ecology ◽  
Prey Availability ◽  
Fork Length ◽  
Stomach Contents ◽  
California Current ◽  
Large Prey ◽  
Dosidicus Gigas ◽  
Important Prey ◽  
Jumbo Squid ◽  
Xiphias Gladius

The feeding ecology of broadbill swordfish (Xiphias gladius) in the California Current was described based on analysis of stomach contents collected by federal fishery observers aboard commercial drift gillnet boats from 2007 to 2014. Prey were identified to the lowest taxonomic level and diet composition was analyzed using univariate and multivariate methods. Of 299 swordfish sampled (74 to 245 cm eye-to-fork length), 292 non-empty stomachs contained remains from 60 prey taxa. Diet consisted mainly of cephalopods but also included epipelagic and mesopelagic teleosts. Jumbo squid (Dosidicus gigas) and Gonatopsis borealis were the most important prey based on the geometric index of importance. Swordfish diet varied with body size, location and year. Jumbo squid, Gonatus spp. and Pacific hake (Merluccius productus) were more important for larger swordfish, reflecting the ability of larger specimens to catch large prey. Jumbo squid, Gonatus spp. and market squid (Doryteuthis opalescens) were more important in swordfish diet in inshore waters, while G. borealis and Pacific hake predominated offshore. Jumbo squid was more important from 2007-2010 than in 2011-2014, with Pacific hake the most important prey item in the latter period. Diet variation by area and year probably reflects differences in swordfish preference, prey availability, prey distribution, and prey abundance. The range expansion of jumbo squid that occurred during the first decade of this century may particularly explain their prominence in swordfish diet from 2007-2010. Some factors that may influence dietary variation in swordfish were identified. Standardization could make future studies more comparable for conservation monitoring purposes.

Striped marlin (Kajikia audax) diet variability off Cabo San Lucas, B.C.S., Mexico during El Niño–La Niña events

2017 ◽  
Vol 98 (6) ◽  
pp. 1513-1524 ◽  
Author(s):  
Sofía Ortega Garcia ◽  
Dana I. Arizmendi-Rodríguez ◽  
Marcela S. Zúñiga-Flores
Keyword(s):  
Annual Variation ◽  
Stomach Contents ◽  
Diet Breadth ◽  
Dosidicus Gigas ◽  
Important Prey ◽  
Jumbo Squid ◽  
Diet Variability ◽  
Analysis Of Similarity ◽  
Index Of Relative Importance ◽  
Prey Items

The stomach contents of 1261 striped marlins caught from 2007 to 2010 by the sport-fishing fleet of Cabo San Lucas, Baja California Sur, Mexico, were analysed, taking into account sea surface temperatures estimated using satellite images of the study area and the Oceanic Niño Index (ONI). The analysis allowed the identification of three anomalously cold periods during 2007, 2008 and 2010 and a warm period in 2009. The stomach content results showed 89 different prey items eaten during the study period. Of the specimens captured, 868 (69%) stomachs contained food items. The most important prey items were cephalopods (Dosidicus gigas and Argonauta spp.) and fish (Scomber japonicus, Selar crumenophthalmus and Sardinops caeruleus). Despite having a broad trophic spectrum, the striped marlin was classified as a specialist consumer, with Bi = 0.03. Based on the diet breadth value and the prey-specific index of relative importance (PSIRI), the jumbo squid, D. gigas, was the main prey species, coinciding with cold periods. On the other hand, the fishes S. caeruleus and S. japonicus showed the highest PSIRI values during the 2009 warm anomalies. Analysis of similarity showed the formation of four groups in relation to PSIRI values. According to a non-metric multidimensional scaling ordination, these groups were formed with a similarity of 30% and a stress of 0.17. These results demonstrate inter-annual variation in the diet as well as in the availability and abundance of prey items.

Feeding ecology of black anglerfish Lophius budegassa: seasonal, bathymetric and ontogenetic shifts

2006 ◽  
Vol 86 (4) ◽  
pp. 877-884 ◽  
Author(s):  
Izaskun Preciado ◽  
Francisco Velasco ◽  
Ignacio Olaso ◽  
Jorge Landa
Keyword(s):  
North Atlantic ◽  
Feeding Ecology ◽  
Diet Composition ◽  
Atlantic Coast ◽  
Stomach Contents ◽  
Large Prey ◽  
Age Classes ◽  
Feeding Intensity ◽  
Merluccius Merluccius ◽  
Important Prey

The diet of black anglerfish Lophius budegassa is described for the Cantabrian Sea (North Atlantic coast of Spain) from seasonal samples obtained onboard commercial vessels from January 1993 to December 1994. The stomach contents of fish caught on the continental shelf were examined, and differences in the diet in relation to age-class, season and depth were studied. The age-classes were grouped according to a cluster analysis of diet composition. As a result, three groups were obtained: the first two corresponded to juveniles between 2 and 7 years old, and the third one corresponded to adults between 8 and 15 years old. Although Micromesistius poutassou was an important prey for all ages, the youngest black anglerfish fed mainly on small benthic fish. In contrast, large prey species such as Phycis blennoides and Merluccius merluccius were eaten almost exclusively by adults. The diet composition changed during the year. The changes in the diet of black anglerfish older than 3 years were more related to seasonal differences than to between-size differences. These seasonal shifts were mainly marked by the varying importance of Trachurus trachurus and M. merluccius in their diet. Feeding intensity also showed seasonal variations, with a significant decrease in autumn. An indirect effect of depth on the feeding ecology of black anglerfish was also found, since both age and diet composition changed with depth.

Stable isotopes in jumbo squid (Dosidicus gigas) beaks to estimate its trophic position: comparison between stomach contents and stable isotopes

2006 ◽  
Vol 86 (2) ◽  
pp. 437-445 ◽  
Author(s):  
R.I. Ruiz-Cooley ◽  
Unai Markaida ◽  
D. Gendron ◽  
S. Aguíñiga
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Trophic Position ◽  
Stomach Contents ◽  
Isotope Ratios ◽  
Trophic Relationships ◽  
Dosidicus Gigas ◽  
Jumbo Squid ◽  
C And N ◽  
Biomass Increase

Stomach contents and carbon (C) and nitrogen (N) stable isotope analysis were used to evaluate trophic relationships of jumbo squid, Dosidicus gigas. Buccal masses, beaks and stomach contents of large and medium maturing-sized jumbo squid and muscle from its main prey, the myctophid Benthosema panamense, were collected in the Gulf of California, Mexico during 1996, 1997 and 1999. Both the quantified C and N-isotope ratios in muscle, and stomach content analysis revealed that larger-sized maturing squid showed a higher trophic position than medium-sized individuals. However, a discrepancy between stomach contents versus stable isotope analyses was found in evaluating trophic relationships. Simple dilution models as a function of growth were used to estimate the C and N renewal dietary shift for jumbo squid. Estimates of the initial C and N pools in D. gigas with an initial age of 70 days and 210 days indicated isotopic shifts of 32% after a threefold biomass increase and 25% after a fourfold biomass increase, respectively. Additionally, beak samples of jumbo squid were evaluated as an alternative tissue to estimate squid trophic position using stable isotopes. The results showed a significant correlation between stable isotope ratios from muscle and beak samples. Muscle isotope values were higher than beak by 1% and 4% for δ13C and δ15N respectively. A test with jumbo squid beaks collected from a stomach of a stranded sperm whale confirmed the viability of this method.

scholarly journals Prey availability influences the diet of Scinax fuscomarginatus in a Cerrado area, Central Brazil

2020 ◽  
pp. 169-175
Author(s):  
G. Michelin ◽  
K. Ceron ◽  
D. J. Santana
Keyword(s):  
Prey Availability ◽  
Stomach Contents ◽  
Selectivity Index ◽  
Generalist Predators ◽  
Mato Grosso ◽  
Central Brazil ◽  
Important Prey ◽  
Prey Composition ◽  
Generalist Diet ◽  
Mato Grosso Do Sul

Prey availability in an environment may change seasonally and these changes should be considered as determinant factors for the diets of anurans. Scinax species are generalist predators that feed on arthropods, but data concernning their diet in relation to prey availability are lacking. In this study, we describe the diet of Scinax fuscomarginatus by evaluating its possibly generalist diet related to prey availability in its environment. We studied the diet of Scinax fuscomarginatus by analysing the stomach contents of 48 individuals captured in the Campo Grande municipality, Mato Grosso do Sul state, Brazil. We found eight prey categories, the most common and most representative being Hemiptera. The selectivity index of the two most important prey varied inversely between dry and wet seasons. Prey availability also varied between seasons. These results suggest a temporal pattern in prey composition and in the diet of Scinax fuscomarginatus.

scholarly journals Intraspecific variation in the diet of the Mexican garter snakeThamnophis eques

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4036 ◽  
Author(s):  
Javier Manjarrez ◽  
Martha Pacheco-Tinoco ◽  
Crystian S. Venegas-Barrera
Keyword(s):  
Intraspecific Variation ◽  
Resource Competition ◽  
Prey Availability ◽  
General Pattern ◽  
Stomach Contents ◽  
Large Prey ◽  
Male And Female ◽  
Males And Females ◽  
Prey Items

The Mexican Garter Snake (Thamnophis eques)is a terrestrial-aquatic generalist that feeds on both aquatic and terrestrial prey. We describe size-related variation and sexual variation in the diet ofT. equesthrough analysis of 262 samples of identifiable stomach contents in snakes from 23 locations on the Mexican Plateau. The snakeT. equeswe studied consumed mostly fish, followed in lesser amounts by leeches, earthworms, frogs, and tadpoles. Correspondence analysis suggested that the frequency of consumption of various prey items differed between the categories of age but not between sex of snakes, and the general pattern was a reduction of prey item diversity with size of snake. Snake length was correlated positively with mass of ingested prey. Large snakes consumed large prey and continued to consume smaller prey. In general, no differences were found between the prey taxa of male and female snakes, although males ate two times more tadpoles than females. Males and females did not differ in the mass of leeches, earthworms, fishes, frogs and tadpoles that they ate, and males and females that ate each prey taxon were similar in length. We discuss proximate and functional determinants of diet and suggest that the observed intraspecific variation inT. equescould be explored by temporal variation in prey availability, proportions of snake size classes and possible sexual dimorphism in head traits and prey dimensions to assess the role of intersexual resource competition.

Food and feeding habits of jumbo squid Dosidicus gigas (Cephalopoda: Ommastrephidae) from the Gulf of California, Mexico

2003 ◽  
Vol 83 (3) ◽  
pp. 507-522 ◽  
Author(s):  
Unai Markaida ◽  
Oscar Sosa-Nishizaki
Keyword(s):  
Gulf Of California ◽  
Environmental Changes ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Dosidicus Gigas ◽  
Fish Prey ◽  
Monthly Basis ◽  
Jumbo Squid ◽  
Food And Feeding ◽  
Northern Anchovy

Stomach contents of 533 jumbo squid, Dosidicus gigas, ranging between 14·5 and 87·5 cm dorsal mantle length were collected on a monthly basis in the central Gulf of California from November 1995 to April 1997. Fish prey were identified by sagittal otoliths, cephalopods by beaks and crustaceans by exoskeletal features. The diet was dominated by Benthosema panamense, an abundant near-shore nyctoepipelagic myctophid that forms dense aggregations. Another myctophid, Triphoturus mexicanus, several micronektonic squid, pelagic red crab and small pelagic fish such as northern anchovy and Pacific sardine played a secondary role. The largest differences in diet were due to spatial and monthly changes, while differences regarding squid size or sex were smaller. Prey size (averaging 5–7 cm) and prey number did not vary with size of jumbo squid. Jumbo squid in the slopes of the Guaymas basin feed on abundant schooling mesopelagic micronekton of annual nature with a quick response to environmental changes, which could partly explain the large annual fluctuations of this commercial resource.

Foraging ecology and movement patterns of jumbo squid (Dosidicus gigas) in the California Current System

2013 ◽  
Vol 95 ◽  
pp. 37-51 ◽  
Author(s):  
John C. Field ◽  
Carl Elliger ◽  
Ken Baltz ◽  
Graham E. Gillespie ◽  
William F. Gilly ◽  
...  
Keyword(s):  
Foraging Ecology ◽  
Current System ◽  
California Current ◽  
Movement Patterns ◽  
Dosidicus Gigas ◽  
California Current System ◽  
Jumbo Squid

scholarly journals Intraspecific variation in the diet of the Mexican garter snake Thamnophis eques

2016 ◽  
Author(s):  
Javier Manjarrez ◽  
Martha Pacheco-Tinoco ◽  
Crystian S Venegas-Barrera
Keyword(s):  
Intraspecific Variation ◽  
Resource Competition ◽  
Prey Availability ◽  
General Pattern ◽  
Stomach Contents ◽  
Garter Snake ◽  
Large Prey ◽  
Garter Snakes ◽  
Males And Females ◽  
Prey Items

The Mexican Garter Snake (Thamnophis eques) is a terrestrial-aquatic generalist because it feeds on both aquatic and terrestrial prey. We describe size-related variation and slight sexual variation in the diet of Thamnophis eques through analysis of 262 samples of identifiable stomach contents in snakes from 23 locations on the Mexican Plateau. The Mexican Garter Snakes we studied ate prey items mostly fish, followed in lesser amounts, respectively, by leeches, earthworms, frogs, and tadpoles. Correspondence analysis suggested that the frequency of consumption of various prey items differed between the categories of age and sex of snakes, and the general pattern was a reduction of prey item diversity with size of snake. Snake length was correlated positively with mass of ingested prey. Large snakes consumed large prey and continued to consume smaller prey. In general, no differences were found between the prey taxa of male and female snakes, although males ate two times more tadpoles than females. Males and females did not differ in the mass of leeches, earthworms, fishes, frogs and tadpoles that they ate, and males and females that ate each prey taxon were similar in length. We discuss proximate and functional determinants of diet and suggest that the observed intraspecific variation in Mexican Garter Snakes could be explored by temporal variation in prey availability, proportions of snake size classes and possible sexual dimorphism in head traits and prey dimensions to assess the role of intersexual resource competition.

scholarly journals Intraspecific variation in the diet of the Mexican garter snake Thamnophis eques

2016 ◽  
Author(s):  
Javier Manjarrez ◽  
Martha Pacheco-Tinoco ◽  
Crystian S Venegas-Barrera
Keyword(s):  
Intraspecific Variation ◽  
Resource Competition ◽  
Prey Availability ◽  
General Pattern ◽  
Stomach Contents ◽  
Garter Snake ◽  
Large Prey ◽  
Garter Snakes ◽  
Males And Females ◽  
Prey Items

The Mexican Garter Snake (Thamnophis eques) is a terrestrial-aquatic generalist because it feeds on both aquatic and terrestrial prey. We describe size-related variation and slight sexual variation in the diet of Thamnophis eques through analysis of 262 samples of identifiable stomach contents in snakes from 23 locations on the Mexican Plateau. The Mexican Garter Snakes we studied ate prey items mostly fish, followed in lesser amounts, respectively, by leeches, earthworms, frogs, and tadpoles. Correspondence analysis suggested that the frequency of consumption of various prey items differed between the categories of age and sex of snakes, and the general pattern was a reduction of prey item diversity with size of snake. Snake length was correlated positively with mass of ingested prey. Large snakes consumed large prey and continued to consume smaller prey. In general, no differences were found between the prey taxa of male and female snakes, although males ate two times more tadpoles than females. Males and females did not differ in the mass of leeches, earthworms, fishes, frogs and tadpoles that they ate, and males and females that ate each prey taxon were similar in length. We discuss proximate and functional determinants of diet and suggest that the observed intraspecific variation in Mexican Garter Snakes could be explored by temporal variation in prey availability, proportions of snake size classes and possible sexual dimorphism in head traits and prey dimensions to assess the role of intersexual resource competition.

Sign in / Sign up

Export Citation Format

Share Document