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

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)

Shift in diet composition of Indian mackerel Rastrelliger kanagurta - an analysis in relation to climate change

The feeding regime of organisms depend on the plankton community structure which is being studied worldwide to assess the changes in marine ecosystem structure due to climate change or anthropogenic activities. An attempt is made here to study the seasonal and long term variation in feed composition of Indian mackerel over a period of 40 years and its relationship with sea surface temperature to elucidate structural changes in food composition if any over period of time and its relationship to the primary and secondary productivity in eastern Arabian Sea marine ecosystem. The diet study during 2011-2014 reported the domination of phytoplankton consisting of Coscinodiscus sp. consistently and the presence of macroplankton and fish larvae whereas the diet during 1960-1961 showed the dominance of zooplankton and copepods. It could be assumed that increase in sea surface temperature which resulted in dominance of phytoplankton community as reported elsewhere in the world is also observed in eastern Arabian Sea which is reflected in the diet regime of Indian mackerel. The results also indicate its facultative feeding behaviour by compensating the low value phytoplankton with high value macroplankton and hence can be considered as a resilient species with regard to climate change

Instance of unusual feeding habit of the Indian Mackerel, Rastrelliger kanagurta from the Mangalore Fishing Harbour

The Indian mackerel, Rastrelliger kanagurta contributes significantly to the pelagic fishery catch of Dakshina Kannada coast. The fishing season extends from Aug. to May with peak landings during September-November and April-May. Fishing is done by purseseiners, trawlers, gillnetters, ring seiners and indigeneous non mechanized crafts

Climate influence on oil sardine and Indian mackerel in Southeastern Arabian sea

The anomalies of sea surface temperature, coastal upwelling index, rainfall, multivariate ENSO index and chlorophyll a were analysed and correlated with catch rate anomalies of oil sardine and Indian mackerel exploited by purse seine along the coastal waters off Karnataka, India in South-Eastern Arabian Sea during period 1990–2014. The purse seines in Karnataka contributed on an average 75% and 65% catch of oil sardine and Indian mackerel respectively. The catch rate anomalies of oil sardine, showed a significant positive correlation with sea surface temperature and negative statistical correlation with multivariate ENSO index. Such significant relationship was not observed in the case of Indian mackerel. The relationship of those parameters to variations in catch distribution of oil sardine and Indian mackerel was explored with a generalized additive model. The GAM results indicated that for sardine, sea surface temperature ( R–sq = 0.339) with 40.8% deviance and for mackerel, chlorophyll a (R–sq =0.419) with 58.9% deviance were better than other climatological factors and can be considered as a climatological predictor of catches in the region. The study also indicated a combination of sea surface temperature and multivariate ENSO index anomalies had better deviance of 56% for oil sardin

Aberrations in the feeding behaviour of the Indian Mackerel, Rastrelliger kanagurta

The food and feeding habits of the mackerel have been studied extensively, which suggest that mackerel generally adopts either filter feeding or preying on the individual animals. Plankton consisting of copepods, diatoms and dino-flagellates and small crustaceans such as the Acetes sp. are reported in their feed. However, a deviation from the normal feeding habit was observed in the gut analysis of mackerel collected on 8th October 2013 from trawlers at Mangalore Fisheries Harbour. Among the 50 stomachs analysed 4% contained oil sardines juveniles and 2% had digested squid remains as a food item. The specimens which ranged from 192 mm to 285 mm in total length and weighed 67 g to 224 g were mature with their gonad in spent or spent recovery stages. The semi-digested oil sardine present in the gut of mackerel ranged in size from 36 to 81 mm

Enigmatic Indian Oil Sardine: An Insight

Marine capture fisheries is an important component of the fisheries sector in India, generating livelihood avenues for an estimated 3.79 million fishers directly besides those involved in the secondary and tertiary structures concerned with fish marketing, processing and exports of fish and fishery products. Sustainable harvesting of the marine fishery resources is important in a scenario where there is large scale over-capitalisation in the sector and abrupt and long-term disruptions in environmental parameters due to climate change related processes. The Indian Oil Sardine, a major single species fishery in India accounts for 17 - 20% of the total marine fish landings. At the national level, in landing volumes it is the top ranked species during most years. Among marine fishes, its importance as a favoured table fish and rich source of fish oils creates a unique position for the Indian oil sardine in terms of its economic value. However, the resource is prone to sudden fluctuations in abundance that makes it an enigma to researchers, fishers and managers. ICAR-Central Marine Fisheries Research Institute has conducted extensive research on the resource since its inception and several aspects of its biology, fishery and stock assessment have been reported periodically. Considering the importance of this resource to the marine fisheries sector of India, it is important to compile all existing information and subsequent research insights to assist its efficient management along the Indian coast. I am happy that the scientists of the Pelagic Fisheries Division of CMFRI have completed the task of compiling all recent information and analysed large amount of data collected pertaining to the Indian Oil Sardine in this document for the benefit of all stakeholders interested in knowing about this valuable fishery resource

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Not AvailableThe Indian mackerel, Rastrelliger kanagurta contributes significantly to the pelagic fishery catch of Dakshina Kannada coast. The fishing season extends from Aug. to May with peak landings during September-November and April-May. Fishing is done by purseseiners, trawlers, gillnetters, ring seiners and indigeneous non mechanized crafts.Not Availabl

Not Available

Not AvailableScomberomorus 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).Not Availabl

Not Available

Not AvailableThe feeding regime of organisms depend on the plankton community structure which is being studied worldwide to assess the changes in marine ecosystem structure due to climate change or anthropogenic activities. An attempt is made here to study the seasonal and long term variation in feed composition of Indian mackerel over a period of 40 years and its relationship with sea surface temperature to elucidate structural changes in food composition if any over period of time and its relationship to the primary and secondary productivity in eastern Arabian Sea marine ecosystem. The diet study during 2011-2014 reported the domination of phytoplankton consisting of Coscinodiscus sp. consistently and the presence of macroplankton and fish larvae whereas the diet during 1960-1961 showed the dominance of zooplankton and copepods. It could be assumed that increase in sea surface temperature which resulted in dominance of phytoplankton community as reported elsewhere in the world is also observed in eastern Arabian Sea which is reflected in the diet regime of Indian mackerel. The results also indicate its facultative feeding behaviour by compensating the low value phytoplankton with high value macroplankton and hence can be considered as a resilient species with regard to climate change.Not Availabl