Diet of Hydromedusa tectifera (Testudines-Chelidae) in a mountain stream of Córdoba province, Argentina

2009 ◽  
Vol 30 (4) ◽  
pp. 545-554 ◽  
Author(s):  
Julián Lescano ◽  
Marcelo Bonino ◽  
Gerardo Leynaud ◽  
José Haro
Keyword(s):  
Diversity Index ◽  
Stomach Contents ◽  
Detrended Correspondence Analysis ◽  
Mountain Streams ◽  
Mountain Stream ◽  
Relative Importance ◽  
Size Classes ◽  
Food Items ◽  
Index Of Relative Importance ◽  
Morisita Index

AbstractThe diet of Hydromedusa tectifera occurring in two mountain streams in the province of Córdoba is described through a comparative analysis of 154 individuals. Turtles were manually captured between August 2005 and August 2006 from streams at the localities of Tanti and Flor Serrana. Before being released, turtles were stomach-flushed, and sex and carapace length were recorded. The stomach contents were observed under stereomicroscope; prey items were identified and classified according to size and volume. The importance of the different items was quantified using the Index of Relative Importance (IRI). Similarity in the diet between sexes and among size classes and seasons of an annual cycle was evaluated using the simplified Morisita index. Trophic breadth was estimated with the Shannon diversity index. Detrended Correspondence Analysis (DCA) was used to evaluate differences in the diet between categories (sex, size classes). Forty-seven food items belonging to the following taxa were identified: leeches, annelids, gastropods, arachnids, insects, and fishes. According to the IRI value, the most important items in the diet of H. tectifera were larvae of Trichoptera (IRI = 33.5), fishes (IRI = 30), and naiads of Odonata (IRI = 25.2). The relative importance of the items varied with size of turtles but not with sex. Size of prey consumed increased with increasing turtle size. A greater trophic breadth was observed in smaller individuals.

scholarly journals Diet of the freshwater stingray Potamotrygon motoro (Chondrichthyes: Potamotrygonidae) on Marajó Island (Pará, Brazil)

2010 ◽  
Vol 70 (1) ◽  
pp. 155-162 ◽  
Author(s):  
MP. Almeida ◽  
PMO. Lins ◽  
P. Charvet-Almeida ◽  
RB. Barthem
Keyword(s):  
Stomach Contents ◽  
Relative Importance ◽  
Food Items ◽  
Freshwater Stingray ◽  
Marajó Island ◽  
Index Of Relative Importance

The stomach contents of 137 examples of Potamotrygon motoro caught in 3 locations (Muaná, Afuá and Lake Arari) on Marajó Island were analysed. The values of the Index of Relative Importance (IRI) and its respective percentage (%IRI) were calculated. The level of repletion 1 (¼ full) was the most representative for both sexes, as well as for immature and mature specimens. Most of the food items found were well-digested. The food items identification indicated the presence of 15 orders, including insects, mollusks, crustaceans, annelids and fish. Differences in diet were observed among the locations studied when comparing %IRI, crustaceans being the most preferred in Afuá, fish in Lake Arari and mollusks in Muaná.

Diets of commercially exploited fish from Bass Strait and adjacent Victorian Waters, south-eastern Australia

1984 ◽  
Vol 35 (5) ◽  
pp. 549 ◽  
Author(s):  
N Coleman ◽  
M Mobley
Keyword(s):  
Stomach Contents ◽  
Relative Importance ◽  
Food Items ◽  
South Eastern ◽  
Major Food ◽  
Eastern Australia ◽  
Commercial Species ◽  
Index Of Relative Importance ◽  
South Eastern Australia

Stomach contents were analysed to investigate the diets of 52 commercial species of fish. Fish were collected from Bass Strait and adjacent Victorian waters, south-eastern Australia; samples effectively covered the whole of the Victorian coast. Particular emphasis was placed on estimating the importance of arrow squid, Nototodarus gouldri in the diets of the species investigated. For most of the species investigated, the major food items (expressed as the proportion of stomach contents by number, weight and volume or through the calculation of the Index of Relative Importance) were fish or crustaceans. Cephalopods were found in the diets of 21 species but provided a major proportion of the stomach contents in only six species. Arrow squid did not appear to be a major item in the diets of any of the species investigated. For those species that eat large amounts of cephalopods, it appears to be octopus, rather than squid, that is of most significance in the diet.

scholarly journals Seasonal variation on diet of juvenile Elops saurus Linnaeus, 1766 (Ladyfish) in the Parnaiba River Delta

2020 ◽  
Vol 32 ◽  
Author(s):  
Tatiane Araujo Santos ◽  
Thamires Souza Gonçalves ◽  
Patricia Silva do Nascimento ◽  
Cézar Augusto Freire Fernandes ◽  
Francisca Edna de Andrade Cunha
Keyword(s):  
High Frequency ◽  
Rainy Season ◽  
Stomach Contents ◽  
Dry Season ◽  
River Delta ◽  
Frequency Of Occurrence ◽  
Relative Importance ◽  
Dry Period ◽  
Food Items ◽  
Importance Index

Abstract: Aim Identify seasonal variations in the diet of juvenile living in the estuary of the Parnaíba River Delta. Methods Food items were identified through analysis of stomach contents, and later submitted to analysis by regular methods for Frequency of Occurrence (FO), Frequency Numerical (FN), Gravimetric Frequency (FW) and Relative Importance Index (IRI). Results Juvenile diet of Elops saurus that inhabit the lagoons in the Parnaíba delta was composed in order decreasing of importance by Osteichthyes (Teleostei), Insecta and Crustacea in addition to Polychaeta and Nematoda. It was also observed a high frequency of occurrence of fragments of plastics in the diet. In the rainy season, 17 items were recorded in the diet, whereas in the dry season only 7 items were present. Relative Importance Index showed high presence of the Teleostei fish (69.93%) on diet of E. saurus during the rainy season, whereas during the dry period the insects of the families Corixidae (43.25%) and Dysticidae (39.16%). Conclusions With the study it was possible to identify that juvenile are piscivorous in the rainy season when there is a higher availability of prey in the environment and insectivores in the dry season when it reduces the supply of food, indicating feeding flexibility to environmental alterations.

scholarly journals Spatial and seasonal changes in the diet of Oligosarcus hepsetus (Characiformes, Characidae) in a Brazilian Reservoir

2005 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
F. G Araújo ◽  
C. C Andrade ◽  
R. N Santos ◽  
A. F. G. N Santos ◽  
L. N Santos
Keyword(s):  
Seasonal Changes ◽  
Prey Capture ◽  
Gut Contents ◽  
Relative Importance ◽  
Food Items ◽  
Dietary Shifts ◽  
Index Of Relative Importance ◽  
Almost All ◽  
Previous Autumn ◽  
Very High

We assessed spatial and seasonal changes in the diet of Oligosarcus hepsetus in order to describe the strategy developed by this species that allows their very high abundance in Lajes reservoir, Rio de Janeiro, Brazil. Fish samplings were carried out using gill nets, deployed during ca. 12 and 24 hours, between April 2001 and May 2002. A total of 289 individuals were examined, of which 97 showed gut contents. We used the index of relative importance (IRI) to compare probable dietary shifts, and the frequency of occurrence (% OC) to analyze possible ontogenetic influences on feeding. O. hepsetus showed carnivorous habits, feeding preferably on fish and insects, the latter of which occurred in 71.0% of the guts presenting contents. O. hepsetus consumed different items along the three reservoir zones: insects (61.0% IRI) and Cichla monoculus (38.9% IRI) in the lower zone; Lepidoptera (57.0% IRI) in the middle zone; and C. monoculus (77.0% IRI) in the upper zone. Food items changed seasonally with C. monoculus predominating in autumn 2001, and Hymenoptera and Lepidoptera in the winter. In spring almost all food was Lepidoptera (99.8% IRI), while in the summer Hemiptera dominated in the diet. In autumn 2002 Hemiptera (97.0% IRI) was dominant, in significant contrast with the previous autumn. Individuals smaller than 190 mm SL fed heavily on insects, while fishes predominated in the diet of individuals larger than 190 mm SL. Shifts in prey-capture ability among length classes suggest decreasing intraspecific competition. A higher food plasticity seems to be the strategy employed by this opportunist species, which used food resources available in the reservoir.

Hard prey specialists or opportunistic generalists? An examination of the diet of the cownose ray, Rhinoptera bonasus

2007 ◽  
Vol 58 (1) ◽  
pp. 135 ◽  
Author(s):  
A. B. Collins ◽  
M. R. Heupel ◽  
R. E. Hueter ◽  
P. J. Motta
Keyword(s):  
Feeding Behaviour ◽  
Stomach Contents ◽  
Relative Importance ◽  
Charlotte Harbor ◽  
Severe Damage ◽  
Important Prey ◽  
Cownose Ray ◽  
Rhinoptera Bonasus ◽  
Group Feeding ◽  
Index Of Relative Importance

Atlantic cownose rays (Rhinoptera bonasus) are benthic, suction feeders whose foraging activities have been implicated in severe damage to commercial shellfish industries. With jaws highly modified for durophagy, it has been assumed that R. bonasus are crushing specialists that feed primarily upon hard molluscan prey. Stomach contents from R. bonasus caught within Florida’s Charlotte Harbor estuary between July 2003 and July 2004 were analysed using the index of relative importance (IRI) to determine most important prey types. Prey items were identified from 38 families and fell into nine distinctive groups. The three most dominant prey groups were crustaceans (%IRI = 55.31), polychaetes (%IRI = 25.20) and bivalves (%IRI = 12.58). Shoalmates had more similar diets than non-shoalmates, suggesting group feeding. Most small or softer-bodied prey consumed were relatively intact, indicating lack of prey processing and capture through suction feeding. All larger, harder-bodied prey showed evidence of crushing (fractured and broken shells). Although R. bonasus has been characterised as a hard prey specialist, these results suggest it may behave as an opportunistic generalist, modifying feeding behaviour to consume readily available prey.

scholarly journals Feeding habits of Aspitrigla cuculus (L., 1758) (red gurnard), Lepidotrigla cavillone (Lac., 1802) (large scale gurnard) and Trigloporus lastoviza (Brunn., 1768) (rock gurnard) around Cyclades and Dodecanese Islands (E. Mediterranean)

2000 ◽  
Vol 1 (1) ◽  
pp. 91 ◽  
Author(s):  
A. TERRATS ◽  
G. PETRAKIS ◽  
C. PAPACONSTANTINOU
Keyword(s):  
Large Scale ◽  
Eastern Mediterranean ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Frequency Of Occurrence ◽  
Relative Importance ◽  
Bottom Trawling ◽  
Percentage Frequency ◽  
Index Of Relative Importance

The feeding habits of the three most abundant gurnard species, red gurnard (Aspitrigla cuculus), large scale gurnard (Lepidotrigla cavillone) and rock gurnard (Trigloporus lastoviza) in the eastern Mediterranean (Dodecanese and Cyclades, Greece) are examined. The stomach contents of the gurnard specimens collected in April and September 1996 by bottom trawling were analyzed. The % frequency of occurrence, % number and % weight of prey types in the stomach contents were evaluated. By weight, Mysidacea and Decapoda dominated in the diet of the three species in both seasons, however the Index of Relative Importance, as well as the percentage frequency of occurrence varied. Rock gurnard presented the most diverse diet whereas the diet of large scale and red gurnard were more specialized. High overlap in terms of number was found between rock and large scale gurnard in May. Rock gurnard had the most divers diet in both seasons.

scholarly journals Aspectos da alimentação natural de Larimus breviceps Cuvier, 1830, proveniente do litoral norte da Paraíba, Brasil

2020 ◽  
Vol 1 (52) ◽  
pp. 185
Author(s):  
Andreza Da Silva Nascimento ◽  
Jonas De Assis Almeida Ramos
Keyword(s):  
Feeding Habits ◽  
Food Composition ◽  
Marine Debris ◽  
Northern Coast ◽  
Relative Importance ◽  
Synthetic Material ◽  
Fish Feeding ◽  
Food Items ◽  
Index Of Relative Importance ◽  
Social Importance

<p>The knowledge of natural fish feeding is important to understand the species feeding habits and how they interact with the environment. In addition to that, this kind of research can provide relevant data to improve the capture of these animals, considering their economy and social importance. This study aimed to analyze the food composition of Larimus breviceps specimens from the northern coast of Cabedelo city, evaluating the importance of each food item for their diet. The specimens came from the local artisanal fisheries. In laboratory, the individuals were identified, measured and dissected to remove the stomachs content and then examined. Three different analyzes were performed, percentage by frequency of occurrence, by number and by weight, then the index of relative importance (IRI%) was computed. In total, 30 stomachs were analyzed, 15 distinct food items were identified, the most representative prey were fish fragments, Copepoda, Gammaridae, Decapoda (shrimp), algal fragments and synthetic material. Given the results, the diet of this species becomes more diversified as young individuals reach the adults size, and ingest marine debris which indicates an anthropogenic impact.</p>

Swordfish Xiphias gladius diet in the Florida Straits

2020 ◽  
Vol 96 (4) ◽  
pp. 695-706
Author(s):  
Amy M Heemsoth ◽  
Amy C Hirons ◽  
Caroline M Collatos ◽  
David W Kerstetter
Keyword(s):  
Diet Composition ◽  
Stomach Contents ◽  
Relative Importance ◽  
Crustacean Species ◽  
Index Of Relative Importance ◽  
Xiphias Gladius ◽  
Florida Straits ◽  
Prey Length ◽  
Positive Significant Correlation

Swordfish Xiphias gladius inhabit the Florida Straits year-round and provide a significant role in the food web as top-level predators. However, little is known about the diet composition and thus ecological role of swordfish in Florida. This study investigated swordfish diet by analyzing stomach contents of 131 swordfish in the Florida Straits from April 2007 to December 2008. Identifiable species included 13 teleost species, 3 cephalopod species, and 1 crustacean species. Cephalopods dominated the swordfish diet by weight (72.4%) and number (69.9%), and ranked highest in importance in the diet by the index of relative importance (IRI; 81.5%). Teleosts occurred the most (99.1%) but represented the second highest importance in diet by weight (25.2%), number (26.3%), and IRI (17.6%). Illex sp. was the prey with the greatest dietary importance, followed by unidentifiable ommastrephid squids. Stomach fullness index values ranged from 0 (empty) to 8.98 (mean = 0.37). A positive significant correlation between swordfish length and prey length was found (r2 = 0.104, P = 0.037), and no significant correlations were found between swordfish weight and prey weight (r2 = –0.075, P = 0.065). This is the first study to report a comprehensive diet of swordfish inhabiting waters in the Florida Straits region and suggests swordfish may be opportunistic feeders, altering their diet when abundance or presence of prey changes.

Feeding ecology of the piked spurdog Squalus megalops (Chondrichthyes: Squalidae) in the Gulf of Gabès (central Mediterranean Sea)

2018 ◽  
Vol 69 (1) ◽  
pp. 48
Author(s):  
Sondes Marouani ◽  
Hasna Kadri ◽  
Sami Karaa ◽  
Mohamed Nejmeddine Bradai
Keyword(s):  
Feeding Ecology ◽  
Trophic Position ◽  
Stomach Contents ◽  
Size Class ◽  
Relative Importance ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Index Of Relative Importance ◽  
Three Factor

The present study investigated the feeding ecology of the piked spurdog (Squalus megalops) in the Gulf of Gabès (Tunisia) with regard to sex, size class and season. A study of stomach contents from the 630 individuals examined showed that the species consumed teleosts (percentage index of relative importance (%IRI)=80.32), cephalopods (%IRI=11.96) and crustaceans (%IRI=7.68). A three-factor multivariate analysis of variance (MANOVA) demonstrated significant differences in diet related to size, season and sex. Trophic position analysis revealed that S. megalops is a secondary consumer throughout its life. Quantitative analysis indicated that the species is a generalist feeder with an ontogenetic change in preferred prey from crustaceans to teleosts. The niche breadths of S. megalops in both sexes were broad.

Comparison of the Diet of Feral Cats From Rural and Pastoral Western Australia.

1996 ◽  
Vol 23 (4) ◽  
pp. 475 ◽  
Author(s):  
GR Martin ◽  
LE Twigg ◽  
DJ Robinson
Keyword(s):  
Western Australia ◽  
Management Strategies ◽  
Stomach Contents ◽  
Important Food ◽  
Food Category ◽  
Feral Cats ◽  
Food Items ◽  
Dietary Breadth ◽  
Index Of Relative Importance ◽  
Future Management

The stomach contents of 93 cats from rural and pastoral Western Australia were compared using the number and biomass of food items, and by calculating an Index of Relative Importance for each food category. Species of small native mammals (e.g. dasyurids, rodents) and geckos were significantly (P < 0.03) more prevalent in the diet of pastoral cats, and rural cats consumed greater (P < 0.03) quantities of introduced rodents and rabbits. Several other groups of native animals (e.g. snakes, skinks, agamids) were also more prevalent in the stomachs of pastoral cats (P < 0.10). Birds and orthopterans were important food items to cats from both habitats. There was reasonable dietary overlap (mean = 0.71) between the cats from both habitats, but the dietary breadth of the pastoral cats (mean = 0.44) was two-fold greater than that of the rural cats (mean = 0.21). These findings are compared with previous studies, and are discussed with respect to possible implications for future management strategies for feral cats.

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