scholarly journals Food and feeding habits of the narrow barred Spanish mackerel, Scomberomorus commerson (Lacepede, 1800) off Karnataka, south-west coast of India

Author(s):  
K. M. Rajesh ◽  
P. Rohit ◽  
S. Thomas ◽  
V. Suprabha ◽  
G. D. Nataraja ◽  
...  

Scomberomorus commerson were collected on weekly basis during January 2012 to December 2014 at Mangalore Fishing Harbour. Stomach of 214 narrow barred Spanish mackerel measuring from 48 to 105 cm fork length (FL) for males and 45.5 to 115 cm FL for females were analysed to study their feeding habits. Fish with empty stomach were prevalent in almost all the months. Prey mainly comprised of fishes and crustaceans, with the fish component forming 99.9%. The index of relative importance (IRI) showed that the dominant prey were semi-digested fish remains (44.6%) of Sardinella longiceps (30.1%), Decapterus sp. (18.7%), whitebaits (2.5%), Rastrelliger kanagurta (1.5%) and Epinephelus spp. (1.1%), while Saurida sp. (0.7%), Megalaspis cordyla (0.5%), Scombroides sp. (0.2%) and shrimps (0.1%) were found occasionally in the gut. Index of stomach fullness (SFI) was 0.11 in August and 0.65 in January. Generally, SFI was higher during September to January and lower during February to August. The empty stomach ratio (ESR) ranged from 33.3% (August) to 92.3% (April).

1938 ◽  
Vol 59 (2) ◽  
pp. 267-307 ◽  
Author(s):  
Alastair Graham

During recent years there has been a very great advance in our knowledge of the minute structure and function of the various regions and glands of the alimentary canal of the prosobranch and pulmonate gastropods, without any corresponding increase in our understanding of the opisthobranch and, in particular, of the nudibranch gut. That the emphasis should be laid on the streptoneurous and the land-living forms is obviously due to their abundance and to the fact that they include almost all the familiar types of gastropod mollusc, but it is disappointing that, at the moment of writing, there exists only one account of the histology and function of the digestive system of either a dorid or an æolid—to confine attention to the two main types of nudibranch molluscs which occur in British waters—that of Millott (1937b). This is perhaps more noticeable when it is recalled that the nudibranchs have specialised along distinctly unusual lines, many of which are intimately associated with the food and feeding habits which the animals have adopted. The æolids, it is true, have attracted a lively interest in connexion with their possession of nematocysts, but the majority of investigators have apparently been content to trace these into the cnidosacs without concerning themselves over the other constituents of the animal's food.


2019 ◽  
Vol 66 (4) ◽  
Author(s):  
L. Remya ◽  
P.U. Zacharia ◽  
S.P. Shukla ◽  
Molly Varghese ◽  
A.K. Jaiswar ◽  
...  

The relative condition factor (Kn) based on length-weight relationship and food and feeding habits of Jones’ pony fish Eubleekeria jonesi (James, 1971) off Mandapam waters was studied during December 2016 - April 2018. The Kn values showed variations on a monthly basis with maximum value during September (1.23) for male and March (1.53) for female. Analysis of fullness of stomach of 961 samples within the size range of 51-130 mm revealed 40.87% fishes as actively fed, 36.19% as moderately fed and remaining 22.94% as poorly fed. The monthly mean fullness index (FI) was highest during September for both sexes. Highest gonadosomatic index (GSI), vacuity index (VI) and Kn value were observed during March-April in females, probably indicating a spawning peak and hence meagre feeding, which resulted in lowest fullness index (FI). Fishes of smallest length group (51-70 mm) had highest FI and minimum VI and vice versa. The values of index of relative importance (IRI) indicated that the species was planktivorous as well as detritivorous, with top priority towards crustaceans (27.6%) followed by bivalves (23.6%), foraminifera (15.4%), phytoplankton (12.5%), gastropods (9.1%) and nematodes (8.3%) in the gut contents. Diet did not show significant variation either sex-wise or size-wise.


2016 ◽  
Vol 63 (4) ◽  
Author(s):  
K. M. Rajesh ◽  
Prathibha Rohit ◽  
E. M. Abdussamad

Fishery, diet composition and reproductive biology of the dolphinfish Coryphaena hippurus (Linnaeus, 1758) landed along Karnataka Coast during 2013-15 were studied. The estimated average landing of the species in India during the study period was 7975 t of which Karnataka contributed 2.73% (218 t). The fish is mainly exploited by gillnet and also by troll lines operated from trawlers. A few stray specimens were also landed by purse seines. The fork length (FL) was in the range of 32-128 cm and fishes in the length range (FL) of 55-90 cm dominated the catch, contributing 79.8% of the total landings. The most dominant prey item, in terms of occurrence (70.57%) and weight (83.18%) were finfishes followed by cephalopods (19.62% by occurrence and 13.66% by weight) and crustaceans (7.01% occurrence and 1.32% by weight). The index of relative importance (IRI ) values were 85.3, 13.39 and 0.68% respectively for fish, cephalopods and crustaceans respectively. Sex ratio (1:2.05) indicated dominance of females in the fishery. Presence of mature and spent specimens throughout the year suggests that the species spawns all through the year. Peak spawning period was from June to September. This coincided with gradual increase in gonadosomatic index (GSI) values ahead of May which reached a peak during August-September.


2021 ◽  
Vol 9 (12) ◽  
pp. 1346
Author(s):  
Jinn-Shing Weng ◽  
Li-Chi Cheng ◽  
Yun-Sin Lo ◽  
Jen-Chieh Shiao ◽  
Jia-Sin He ◽  
...  

The narrow-barred Spanish mackerel Scomberomorus commerson is an economically essential species; however, few studies have investigated its demographic structure in the northwestern Pacific, which includes Taiwan’s waters. This study examined the growth parameters, age composition, mortality, and sex ratio of S. commerson catches by examining sagittal otoliths and other biological data collected in a 3-year project from June 2018 to June 2021. The transverse sections of sagittal otoliths exhibited alternating translucent and opaque zones, in annual cycles, and this observation was validated by otolith edge analysis. Opaque zones began to form in October; the growth peaked in December and lasted until March. Growth parameters were estimated for female (L∞ = 144.1 cm fork length [FL], k = 0.39 y−1, to = −0.85 y) and male (L∞ = 136.0 cm FL, k = 0.32 y−1, to = −1.49 y) specimens. The maximum recorded FL, body weight, and age were 159.0 cm, 27 kg, and 9.2 y for female and 135.0 cm, 17.8 kg, and 7.2 y for male specimens. Rapid growth was observed for both sexes, with FL reaching 66.8 ± 14.2 cm in female specimens and 70.1 ± 11.0 cm in male specimens during the first year of life. An age–length key based on the direct otolith aging and FL dataset (N = 646) was used to estimate the age composition of 3-year catches measured at landing (N = 16,133). The results verified that the S. commerson currently caught in the central Taiwan Strait are mainly young fish aged 1+ to 2+ y. The estimated fishing mortality (0.27 y−1) and exploitation rate (0.30) suggested that overfishing was not occurring in this stock. The findings of this study have helped clarify the population dynamics of the S. commerson in the Taiwan Strait, and the biological parameters reported herein can aid the management and conservation to ensure the sustainability of this species in this region.


2016 ◽  
Vol 63 (4) ◽  
Author(s):  
P. P. Manojkumar ◽  
P. P. Pavithran

Composition of the diet of greater lizardfish Saurida tumbil (Bloch, 1795), caught from northern Kerala, south-west coast of India was studied and described. The stomachs of 1981 specimens were collected between January, 2012 and June, 2014. Analysis of stomach contents based on index of relative importance (IRI) revealed that this species is exclusively piscivorous. Contrary to other benthic predators of the study area, it mainly feeds on pelagic and demersal fishes(IRI = 63.2), molluscs (IRI = 17.86), crustaceans (IRI = 18.33) and other miscellaneous items (IRI = 2.54). The diet of S. tumbil were found to be related to the seasonal availability of resources, occurrence of juveniles of certain species and on the migration of fishes from nearby places to the study area. Significant changes in prey items were observed between predator length groups, but a positive, significant relationship was recorded between prey size and predator size (p<0.05). Statistical analysis indicated a uniform representation of different diets in the stomach. Maximum similarity in diet between different food items was found in April and November.


2017 ◽  
Vol 9 (2) ◽  
pp. 161-168
Author(s):  
Rama Chandra Ganesh PATURI ◽  
Sarvabhowma Chakravarty MYLA

The food and feeding habits of the shrimp Solenocera melantho off Visakhapatnam coast were studied qualitatively and quantitatively. Feeding intensity differs in relation to gender, size, season and stage of maturity. Detritus was the major component of the food consumed, followed by crustaceans, molluscs, foraminiferans, fish remains, eggs; sand was also found as one of the gut contents. Diet preference in males and females was similar, but varied with size and season. The index of preponderance of detritus was 50.88% in males and 47.16% in females. Variation in feeding intensity was noticed in relation to size, months and season. The overall feeding intensity in males and females was categorized as actively fed (21.52% and 40.78% respectively), moderately fed (22.07%, 19.72%) and poorly fed (14.07%, 27.03%) respectively. S. melantho may designate as an omnivorous detritivore with scavenging activity. 


2020 ◽  
Vol 20 (12) ◽  
pp. 857-866
Author(s):  
Mamidi Satish Kumar ◽  
Shubhadeep Ghosh

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.


Author(s):  
Izza Mahdiana Apriliani ◽  
Lantun P. Dewanti ◽  
Herman Hamdani ◽  
Soraya Gigentika ◽  
Rachmad Cesario ◽  
...  

Analyzing the selectivity of gillnet fishing gear using two different mesh sizes, namely 3.5 and 4 inches. Gillnets of these mesh sizes are commonly used by fishermen in Fish Landing Base (PPI) Cikidang, Pangandaran Regency, West Jawa. A total of 8 fishing trips were conducted at the coastal waters around PPI Cikidang, Pangandaran Regency, West Java from August 2018 to January 2019  using gillnet fishing gear As for each trip, 2-3 times the operation of the tool is carried out. The operation of the fishing gear is carried out with the help of vessels measuring 2-3 Gross Tonnage (GT). The catch obtained was differentiated based on the main catch and bycatch and the amount is calculated for analysis of the proportion of the catch. Mackerel (Scomberomorus commerson) is caught as the main catch, the fork length was measured for analysis of the length frequency distribution and selectivity curves. The operation of gillnets with a mesh size of 3.5 inches obtained a higher proportion of bycatch compared to gillnets with a mesh size of 4 inches. In addition, the length distribution of mackerel caught by gillnets with a mesh size of 3,5 inches is smaller (27-49 cm FL) compared to a mesh size of 4 inches (40-55 cm FL). Based on the distribution of length distribution, gillnets with a mesh size of 3.5 inches are more dominant in catching mackerel in a smaller size class interval than gillnets with a mesh size of 4 inches. Meanwhile, based on the selectivity curve for the length of mackerel with a 50% chance of being caught, it shows that gillnets with a mesh size of 3.5 or 4 inches are selective in catching mackerel, this is because the chances of catching fish at more than L50 are high.


2020 ◽  
Vol 8 (12) ◽  
pp. 939-945
Author(s):  
Tiehoua Kone ◽  
◽  
Irene Kessia Fokouo Kouakou ◽  
Vincent Kadjo ◽  
Konan Nda ◽  
...  

Mugil cephalus is a permanent and abundant fish species in coastal, estuarine or lagoon ecosystems. This species was sampled in the lagoon of Grand-Lahou (Cote dIvoire) for the study of its diet and its feeding ethology. Stomachs were removed and their contents identified using identification keys to determine the diet. 88 specimens of M. cephalus were examined for food and feeding habits. 42 (47.72%) of the fish had empty stomach. Analysis of stomach contents showed that phytoplankton is the most consumed with a numerical percentage of occurrence of 94.98% (Cyanobacteria, Chlorophytes, Diatoms) and a percentage of occurrence is 64.9%. The proportion of zooplankton is 4.98% (cladocerans, copepods, foraminifera, rotifers and nematodes) according to the numerical percentage and 18.77% according to the frequency of occurrence. Detritus has an occurrence percentage of 8.43 %. Diet is mainly composed of diatom.


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