Observations on feeding habits of the common dolphinfish, Coryphaena hippurus (Linnaeus 1758) from the western Bay of Bengal

2021 ◽  
Vol 34 ◽  
pp. 24
Author(s):  
Shubhadeep Ghosh ◽  
Satishkumar Mamidi ◽  
Manas Hoshalli Munivenkatappa ◽  
Prathibha Rohit ◽  
Abdussamad Eruppakkottil Median ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Prey Species ◽  
Niche Breadth ◽  
Feeding Habits ◽  
Weight Ratio ◽  
Primary Study ◽  
Feeding Intensity ◽  
Coryphaena Hippurus ◽  
Dietary Niche ◽  
Western Bay Of Bengal

Coryphaena hippurus is a large pelagic species and constitutes an important by-catch in drift gillnet, trolling and long-line fishing gears operated along the Bay of Bengal, northeastern Indian Ocean. The present study, first from the region, is aimed at deciphering the feeding dynamics from 1150 individuals collected from 2017 to 2019. 32.17% of the fishes had empty stomachs or was with food traces, 45.57% had partially-full stomachs and 22.26% had full stomachs. The feeding intensity was inferred through stomach filling and predator-prey weight ratio, which was higher in May and lower in January, and increasing as increase in the fish size. Coryphaena hippurus is considered a piscivorous pelagic predator as pelagic teleosts contribute more than half of the prey species. Major prey species were big-eye scad (27.3%), squid (10.3%), crabs (9.3%), Indian mackerel (7.2%), Indian scad (5.9%), whitebaits (5.7%) and sardines (5.4%). Scads and crabs were abundantly preyed during summer and winter, while clupeids and engraulids in monsoon; however, no significant variations were observed in prey composition between sizes. Trophic Level was 4.22 ± 0.15 and Levins Standardized Niche Breadth Index was 0.30. Dietary niche breadth was higher during summer (0.48) and monsoon (0.33) and in fishes measuring 60.0–74.9 cm (0.51) and below 45.0 cm (0.48) indicating generalised feeding. This primary study from Bay of Bengal is the first comprehensive report on trophodynamics for the species and would contribute to its management using trophic interactions.

scholarly journals Understanding the Trophodynamics of Yellowfin Tuna, Thunnus albacares (Bonnaterre, 1788) from the Western Bay of Bengal

2020 ◽  
Vol 20 (12) ◽  
pp. 857-866
Author(s):  
Mamidi Satish Kumar ◽  
Shubhadeep Ghosh
Keyword(s):  
Bay Of Bengal ◽  
Niche Breadth ◽  
Feeding Habits ◽  
Feeding Strategy ◽  
Fork Length ◽  
Thunnus Albacares ◽  
Feeding Preferences ◽  
Feeding Intensity ◽  
Food And Feeding ◽  
Western Bay Of Bengal

The trophodynamics of Thunnus albacares (Bonnaterre, 1788) from the western Bay of Bengal was studied during 2012 – 2015. Feeding intensity revealed that 34.6 % of the fishes had empty-trace stomachs, 52.77% of the fishes had quarter full-half full stomachs and 12.44% of the fishes had three fourth full-gorged stomachs. Feeding intensity increased with an increase in body size of the fishes with high prey to predator weight ratios and with a third of the fishes above 160 cm fork length possessing three fourth full-gorged stomachs. Cephalopods (47%) dominated the prey constituents, followed by semi digested finfishes and shellfishes (28%), finfishes (16%) and crustaceans (9%). Significant shifts in prey items were observed with an increase in fish size. Though squids were predominant in the diet, however, with the increase in size, feeding shift has clearly been observed towards finfishes. Feeding preferences did not vary between sexes. Annual and seasonal similarities were recorded in their food and feeding habits. Prey-specific abundance indicated a relative specialized feeding pattern with high occurence of species belonging to the orders Teuthidae and Perciformes. Levins Standardized Niche Breadth Index of 0.16 indicated limited niche width in the feeding strategy of Thunnus albacares.

Feeding habits of John Dory, Zeus faber, off the Portuguese continental coast

1999 ◽  
Vol 79 (2) ◽  
pp. 333-340 ◽  
Author(s):  
Alexandra Silva
Keyword(s):  
Prey Species ◽  
Feeding Habits ◽  
Parallel Evolution ◽  
Stomach Contents ◽  
Abundant Species ◽  
Temporal Variations ◽  
Food Composition ◽  
Diet Shift ◽  
Feeding Intensity ◽  
Zeus Faber

The feeding habits of John Dory (Zeus faber) were studied, based on the analysis of stomach contents from fish sampled in five groundfish surveys. These surveys were carried out off the Portuguese coast during different seasons between 1990 and 1992. The main aspects of feeding biology analysed in this paper are: ontogenetic diet changes, temporal variations in food composition and feeding intensity. Multivariate methods were used to investigate ontogenetic diet shifts. Two main length groups were identified: 8.0–24.9 cm fish, feeding mainly on dragonets and silvery pout, and 25.0–55.9 cm fish whose diet was mainly composed of blue whiting and snipefish. A transitional phase (24.0–30.9 cm fish) with a mixed food composition was observed. This ontogenetic diet shift does not seem to correspond to any important change in body morphology but it does coincide with the onset of sexual maturity in the species.John Dory switched from a diet of small prey species with more pronounced benthic behaviour to a diet of larger schooling pelagic species. This suggests parallel evolution to more pelagic foraging behaviour. However, John Dory feeding habits appear to be largely controlled by the availability and accessibility of prey species: (i) the diet of adult John Dory is dominated by very abundant species; (ii) shifts in the main prey items between different times of the year and between different areas seem to be related both with their absolute and relative abundance in the environment and with the overlap between the depth distribution of predator and prey.

scholarly journals Breeding timing and nest predation rate of sympatric scops owls with different dietary niche breadth

2015 ◽  
Vol 93 (11) ◽  
pp. 841-847 ◽  
Author(s):  
M. Toyama ◽  
N. Kotaka ◽  
I. Koizumi
Keyword(s):  
Nest Predation ◽  
Life History Traits ◽  
Prey Species ◽  
Niche Breadth ◽  
Predation Rate ◽  
Subtropical Forest ◽  
Stabilizing Selection ◽  
Main Prey ◽  
Dietary Niche ◽  
Otus Elegans

Breeding timing is one of the key life-history traits considered to be under strong stabilizing selection, such that offspring should be born when food resources are most abundant. Predation, however, may also affect the breeding timing because nest predation is a leading mortality for many species, although this possibility has been less considered. Here, we examined the possible effects of nest predation on breeding timing by comparing sympatric scops owls in a subtropical forest where only reptilian predators are present. The Japanese Scops Owl (Otus semitorques Temminck and Schlegel, 1844), a dietary generalist, bred one month earlier than the specialist Ryukyu Scops Owl (Otus elegans (Cassin, 1852)). The breeding timing of the Ryukyu Scops Owl matched with the emergence of their main prey species, but also matched with predator activity. Accordingly, the predation rate on eggs or nestlings was 7.5 times higher in the Ryukyu Scops Owl (13.9%; 21 out of 150 nests) than in the Japanese Scops Owl (1.9%; 1 out of 52 nests). Clutch size, on the other hand, was significantly larger in the Ryukyu Scops Owl than in the Japanese Scops Owl, possibly compensating loss from predation. Although alternative explanations still remain, our results suggest that the food generalist might have adjusted its breeding timing to avoid nest predation, whereas the breeding timing of the specialist might have been constrained by the availability of its main prey items.

Reproductive and feeding biology of unicorn leatherjacket, Aluterus monoceros from the Bay of Bengal, Northern Indian Ocean

2021 ◽  
pp. 1-13
Author(s):  
Shubhadeep Ghosh ◽  
Manas Munivenkatappa Hoshalli ◽  
Satishkumar Mamidi ◽  
Prathibha Rohit ◽  
Gopalakrishnan Achamveetil
Keyword(s):  
Indian Ocean ◽  
Bay Of Bengal ◽  
Feeding Activity ◽  
Northern Indian Ocean ◽  
Feeding Intensity ◽  
Comprehensive Information ◽  
Significant Difference ◽  
Size At Sexual Maturity ◽  
Western Bay Of Bengal ◽  
Prey Items

Abstract No prior comprehensive information on the reproductive biology and trophodynamics of Aluterus monoceros was globally available. The present study was performed on 1036 individuals landed along the western Bay of Bengal during 2017 to 2019. Length ranged between 25.3–64.4 cm in females (mean at 48.34 cm) and from 21.5–64.1 cm in males (mean at 47.83 cm). Growth was negatively allometric with no significant difference between sexes. Sex ratio (F:M) was 1.03 with variations based on sizes and months. Size at sexual maturity for females and males was 40.85 and 41.60 cm, respectively. The species spawned throughout the year with major and minor peaks during February to May and October and November. Absolute fecundity increased linearly with length and weight and ranged from 33,640 eggs to 12,39,202 eggs. Stomachs were empty or with trace amounts of food in 59.17%, part-full in 34.07% and full in 6.76% of the fishes. Stomach vacuity and fullness and predator–prey weight ratios varied with an increase in body size, implying higher feeding intensity in large-sized fishes. Feeding activity was more intense during June–August and less during the peak spawning months. The species is omnivorous and a bottom feeder. Teleosts contributed the most to the prey items (43.23% by Index of Preponderance) implying preference for carnivory. Ontogenetic shifts and seasonal variations in prey items were observed. The present study provides paramount information that can significantly contribute to the management and conservation of monacanthid stocks in northern Indian Ocean.

scholarly journals Preliminary analysis of the feeding habits of batoids from the genera Mobula and Myliobatis in Northern Peru

2019 ◽  
Vol 53 (3) ◽  
pp. 367 ◽  
Author(s):  
Javier Jesús Coasaca-Céspedes ◽  
Eduardo Segura-Cobeña ◽  
Rebeca Montero-Taboada ◽  
Adriana Gonzalez-Pestana ◽  
Eliana Alfaro-Córdova ◽  
...  
Keyword(s):  
Trophic Level ◽  
Preliminary Analysis ◽  
Feeding Behaviour ◽  
Niche Breadth ◽  
Feeding Habits ◽  
Small Scale ◽  
Dietary Niche ◽  
Baseline Information ◽  
Northern Peru

Abstract.- This study provides baseline information on the feeding habits of five batoid species from the genera Mobula and Myliobatis sampled from the small-scale driftnet fishery in northern Peru. The diets of Mobula mobular, Mobula munkiana and Mobula thurstoni consisted mainly of euphausiids. Dietary niche breadth indicated a pelagic feeding behaviour of a specialist and a trophic level of a secondary predator for both M. mobular and M. munkiana. In contrast, Myliobatis chilensis and Myliobatis peruvianus consumed mostly gastropods and crustaceans. Dietary niche breadth indicated a feeding behaviour of a benthic specialist and a trophic level of a secondary predator for Myliobatis chilensis.

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