Ribbonfish Trichiurus Lepturus Research Articles

Spatial structure and distribution of ribbonfish Trichiurus lepturus Linnaeus, 1758 along the eastern Arabian Sea

Ribbonfish Trichiurus lepturus is one of the most important pelagic fish resources in India.The west coast of India (WCI) is considered to be the major region where the species isabundant and forms a sizeable fishery. Determining the spatio-temporal abundance of fishis a key requirement for sustainable resource harvest. This paper illustrates the spatialstructure and distribution of ribbonfish along the WCI using the geostatistical technique,semi-variogram modelling. The spatio-temporal distribution map was generated by kriginginterpolation using the global neighbourhood in the study area. The results show that theareas of higher abundance of ribbonfish shifted between seasons, abundance along thenorthern region was high during the post-monsoon, while later shifting southward up to17°N, peaking between 18°N and 19°N. Furthermore, summertime peak abundance tendedto be more coastal in the Mumbai region. Ribbonfish abundance was relatively lower alongthe southern region i.e., below 15°N year-round. This finding provides additional informationto fishery managers and policymakers which will help improve the sustainability of fisheriescoupled with traditional fisheries management measures Keywords:Arabian Sea, GIS, Geo-statistics, Species distributionmodelling, Spatiotemporal management

Analysis of bycatches from mid-water trawl fishery targeting ribbonfish Trichiurus lepturus on the north-west coast of India

Commercial trawl fisheries are closely associated with bycatch and discards and itsignificantly affects the non-target resources, biodiversity, ecosystem function and habitat.The present study analysed bycatch based on data obtained from commercially operatedmultiday midwater trawlers operating off the north-west coast of India during August2017-December 2019. The data revealed that bycatch and discards constituted about 53and 6% respectively of the trawl catch. Mid-water trawl bycatch comprised 92 Teleosts,8 Cephalopods, 12 Crustaceans and 11 Elasmobranch species. The bycatch is mainlycomprised of cuttlefishes, squids, threadfin breams, sciaenids, bullseye and lizardfishes.Further, 93.68% of the bycatch consisted of commercially important fish, hence it wasretained in the vessel. The bycatch rate was high in September (72.81±37.44 kg h-1) whereas,for discards, it was in August (16.25±10.84 kg h-1). Keywords:Arabian Sea. Bycatch, Discard, Midwater trawl,Ribbonfish

Dried fish more prone to microplastics contamination over fresh fish – Higher potential of trophic transfer to human body

Globally, microplastics (MPs) contamination in aquatic organisms is emerging as an alarming phenomenon. In the present study, we investigated MPs in three commercially important fishes (Bombay duck Harpadon nehereus, ribbon fish Trichiurus lepturus and hairfin anchovy Setipinna phasa) in fresh and dried conditions collected from two sites (Chattogram and Kuakata) of the Bay of Bengal. It was evident that fresh T. lepturus ingested highest amount of MPs through the gills (6.41 mps/g) from Chattogram followed by in the gastrointestinal tract, GIT (6.20 mps/g) and in the muscle (1.20 mps/g) from Kuakata. Among the fresh fishes, H. nehereus from Kuakata accumulated highest amount of MPs (0.21 mps/g), while S. phasa from Kuakata contained the least amount of MPs (0.06 mps/g). On the other hand, among the dried fishes, T. lepturus from Kuakata contained highest amount of MPs (46.00 mps/g), while S. phasa from Kuakata retained lowest amount of MPs (2.17 mps/g). Strangely, all the dried fishes showed significantly higher amount of MPs compared to fresh fishes from both the locations. Fiber was the most dominant type of shape of MPs which accounted 66 %, followed by fragment (27.38 %), microbeads (3.59 %), film (1.48 %), foam (1.31 %) and pellet (0.25 %). Size-wise, the major portion (39.66 %) of MPs was present to be in size range less than 0.5 mm followed by 37.67 % in the size range of 0.5–1.0 mm group and rest 22.67 % within 1.0–5.0 mm. Red (41.55 %) colored MPs was the most prominent, followed by brown (22.11 %), blue (16.32 %), pink (11.69 %), purple (5.10 %), and green (2.25 %). Among polymer types, low-density polyethylene (LDPE) was the most common (38 %), followed by polystyrene (PS-22 %), polyvinyl chloride (PVC-16 %), polyamide (PA-13 %) and ethylene-vinyl acetate (EVA-9 %). The present study confirms high occurrence of MPs in the dried fishes over the fresh fishes from the Bay of Bengal, with high potential of trophic transfer to the human body.

Changes in the diet of predatory ribbonfish Trichiurus lepturus Linnaeus, 1758 with increasing body size along Chennai coast

In recent years, it has been recognised that predatory fishes are rapidly declining in marine habitats. Hence, gathering information on biological characteristics such as dietary dynamics of predatory fishes has assumed importance. Considering this, the dietary dynamics of the predatory ribbonfish Trichiuruslepturusfrom Chennai coast was assessed by analysing the stomach condition and contents, with reference to body size. Representatives of the Order Clupeiformes (Index of relative importance, IRI 33.7%) comprising oilsardine, lesser sardines and anchovies were the major prey items of T. lepturus. Predation by T. lepturus was aided by morphological adaptations, such as dentition, hard and spinous gill rakers, short stomach, high body depth-total length ratio of 1: 17.1 and large mouth (gape area of 1534 mm2 in adult fish).With increasing body size, the capacity to predate upon relatively larger prey increased. The differences in diet composition between ribbonfish of small, medium and large size were well-represented byIRI, prey specific abundance and cluster analysis. The fish is a top predator (trophic level: 4.17) and a specialist feeder (niche breadth: 2.63). As specialist feeders have a narrow choice of food, they are more vulnerable to fishing. It is important that management of multispecies fisheries should focus more on the sensitive predatory species.

GIS based mapping of spatio-temporal distribution pattern of ribbonfish Trichiurus lepturus (Linnaeus, 1758) along Saurashtra coast, India

Identification of spatio-temporal distribution of fish species represents fundamental information for stock assessment which in turn is essential for formulation of fishery management plans as well as for GIS based decision making. This study investigated the spatio-temporal distribution and abundance of different life stages of ribbonfish, Trichiurus lepturus (Linnaeus, 1758) off Saurashtra coast. Geographical coordinates of fishing and allied information on the time of fishing, depth of the fishing area as well as catch details were collected using a structured schedule, from selected trawlers operated from Veraval. Information was mapped using a GIS software to get the spatio-temporal distribution of the species. It was observed that juveniles were more abundant along the south Saurashtra coast whereas subadults and adults showed a discontinuous distribution with abundance in the waters off south Saurashtra as well as north Saurashtra coasts.

Spatio-Temporal Variation in Length-Weight Relationships and Condition of the Ribbonfish Trichiurus lepturus (Linnaeus, 1758): Implications for Fisheries Management.

Knowledge of length-weight relationships for commercially exploited fish is an important tool for assessing and managing of fish stocks. However, analyses of length-weight relationship fisheries data typically do not consider the inherent differences in length-weight relationships for fish caught from different habitats, seasons, or years, and this can affect the utility of these data for developing condition indices or calculating fisheries biomass. Here, we investigated length-weight relationships for ribbonfish Trichiurus lepturus in the waters of the Arabian Sea off Oman collected during three periods (2001–02, 2007–08, and 2014–15) and showed that a multivariate modelling approach that considers the areas and seasons in which ribbonfish were caught improved estimation of length-weight relationships. We used the outputs of these models to explore spatio-temporal variations in condition indices and relative weights among ribbonfish, revealing fish of 85–125 cm were in the best overall condition. We also found that condition differed according to where and when fish were caught, with condition lowest during spring and pre-south-west monsoon periods and highest during and after the south-west monsoons. We interpret these differences to be a consequence of variability in temperature and food availability. Based on our findings, we suggest fishing during seasons that have the lowest impact on fish condition and which are commercially most viable; such fishery management would enhance fisheries conservation and economic revenue in the region.

Feeding preference of adult females of ribbonfish Trichiurus lepturus through prey proximate-composition and caloric values

In the present study we analysed the proximate-composition and caloric values of the preferred prey consumed by ribbonfish, Trichiurus lepturus L. 1758 (adult females), that are distributed in the inner continental shelf from northern Rio de Janeiro State, southeastern Brazil (~22ºS), assessing the potential of nutritional and energetic approach as a tool to understand the feeding selective pattern of this marine top carnivore. The preferred prey of this predator composed of fish co-specifics, Pellona harroweri, Chirocentrodon bleekerianus, Lycengraulis grossidens, Peprilus paru, squid Doryteuthis plei, and shrimp Xiphopenaeus kroyeri were collected from 2007 to 2010 for proximate-composition (water, protein, lipid, ash, and carbohydrate) and caloric value analyses. The correspondence analysis showed that protein is the main component in the prey species (61.32% of variance explained), standing out from the other nutrients. Lipid has the highest percentage related to L. grossidens, ash to X. kroyeri and carbohydrate to D. plei. The strong correlations between protein and caloric value (positive) and lipid and caloric value (negative) indicated that T. lepturus is attending its energy demand through the prey protein content. This work elucidated the feeding preference of adult females of T. lepturus in relation to nutritional and caloric content of their preferred prey. The species showed food selectivity to prey that provide more energy per ingested biomass, so that the feeding events can maximize the predator's caloric gain, which is obtained by a protein-based diet.

Diet overlap of immigrant narrow-barred Spanish mackerel Scomberomorus commerson (Lac., 1802) and the largehead hairtail ribbonfish Trichiurus lepturus (L., 1758) in the Egyptian Mediterranean coast

The immigrant S. commerson (Lac., 1802) represents more than 2% of the total Egyptian catch and its distribution stretches from East to West along the Egyptian Mediterranean coast. The feeding habits of T. lepturus and S. commerson were investigated through stomach content analysis of specimens collected from Abu Qir Bay (Egypt) on a seasonal basis from November 1999 to January 2001 using daytime purse seines. The food content range of T. lepturus was wide, including Engraulis encrasicolus, Gobius spp., Sardinella aurita, Sardina pilchardus, fish eggs, amphipods, copepods and shrimps. The main diet constituents of S. commerson included Engraulis encrasicolus, Sardinella aurita, Sardina pilchardus and shrimps. Seasonal variations of feeding activity indicated that food consumption was highest in spring to autumn for T. lepturus and in summer and autumn for S. commerson. The diet overlap in terms of number and weight between the two species was high. Food composition was related to fish size in both examined fishes. Small T. lepturus (less than 30 cm) fed mainly on crustaceans, while larger samples (more than 59 cm) fed only on fishes. Teleosts were the most important food item for S. commerson of all sizes, while this species became piscivorous when larger than 40 cm in length.

Food and feeding habits of ribbonfish Trichiurus lepturus in coastal waters of south-western Taiwan

The catch of ribbonfish Trichiurus lepturus in the coastal waters of south-western Taiwan has significantly declined in recent years. To examine the effects of exploitation on the feeding habits of ribbonfish, 1570 specimens were collected on a monthly basis during March 2002-March 2003 from the landings by trawlers operating in the coastal waters of south-western Taiwan. The size of the ribbonfish ranged from 83–298 mm, preanal length (PL), with a peak at 201–250 mm PL. Although they fed on shrimps and squid, fishes including Benthosema pterotum, Bregmaceros lanceolatus and Encrasicholina heteroloba were their main food items. In particular, B. pterotum was the most important food all year except during summer No evidence of cannibalism was found in this study. No differences between day and night were found in the feeding activity of T. lepturus. However, B. pterotum and Acetes intermedius were the most important prey in the daytime, whereas B. lanceolatus, B. pterotum and E. heteroloba were at night. Feeding activity and the number of food items increased with increasing size of ribbonfish. Their feeding intensity in February to June, the main spawning season, was significantly greater than in other months. Changes in the food and feeding habits of this species before and after the recent period of heavy exploitation are discussed in detail in this study.

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＶＩＩＩ 若狭湾西部海域におけるタチウオの日周期的鉛直移動

To clarify diurnal movements of a ribbon fish Trichiurus lepturus, exploratory fishing expedi-tions utilizing handline, longline and observations through fish finder were made at the mouth of Maixuru Bay, the western Wakasa Bay, on 5 and 8 June, 1985. Hourly angling and observations of echo traces of T. lepturus indicated that the fish signicantly showed diurnal vertical migration.T. lepturus mainly distributed from middle tosurface layers and made scattering school in nighttime. T. lepturus descended to bottom layer until just before sunrise, and made dense school at bottom layer in daytime. T. lepturus ascended and scattered from middle to surface layers in twilight. Feeding activity of T. lepturus was increased in twilights. Diurnal movements of T. lepturus synchronized with that of anchovy Engraulis japonicus which was thelr main food in this area. This sychronizing might brought T. lepturus to increase chances of encounter wih the food. Bottom longliners at this area also synchronized their managements with diurnal movomots of the fish to effeciently catch them.

Development of the sense organs of ribbonfish Trichiurus lepturus larvae and juveniles.

The morphology of the sense organs of the larvae and juveniles of the ribbonfish Trichiurus lepturus in Wakasa Bay was examined to obtain insights on changes in behavior and habitats with growth of the fish. Development of the sense organs proceeded in accord with the rest of the morphological development of the larvae and juveniles. Sense organs required for feeding were formed at the onset of exogenous feeding. The taste buds first appeared at the begining of the postlarval period and increased in number in association with the pharyngeal teeth and gill arches. During the late phase postlarval period, the lateral line canal on the head and the olfactory rescue were formed. The retinae became duplex and developed horizontal cells in three layers; this is inferred to be advantageous for a piscivorous feeding habit. The presence of well developed sense organs synchronized with the active migration of postlarvae from offshre to coastal waters.

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＶＩＩ 若狭湾西部海域におけるタチウオの成熟と産卵

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＶＩＩ 若狭湾西部海域におけるタチウオの成熟と産卵

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＶＩ 若狭湾西部海域におけるタチウオの年齢と成長

Favourite preys for ribbon fish Trichiurus lepturus (1.9-397.0mm in anal length) were described, based upon the progressive changes in the gut contents with growth. 512 ribbon fish were caught by larva net, beach seine, beam trawl, set net, purse seine, gill net and Danish seine during the years from 1980 to 1983 in the western Wakasa Bay. The occurrence method and the number method were used in the analysis of the food habit of the fish.The ribbon fish of less than 20mm in anal length was zooplankton feeder. The food habit of the fish 20-100mm length was carnivorous and the main foods of the fish were Natantia, Mysidacea and Pisces (mainly anchovy larvae). The fish of more than 100mm length had the piscivorous food habit and the main foods were anchovy and sardine.A particular size of the ribbon fish, which started feeding on other fishes in the western Wakasa Bay, was smaller than that of the East and Yellow China Sea, the adjacent waters of Tsushima and Osaka Bay. In common with each area, however, the fish of more than 250mm in anal length had the piscivorous food habit.The ribbon fish even at the early post larval stage had high feeding ability and positively fed on copepods such as Paracalanus parvus and Paracalanus sp., while the foods of 8 species at the same stage appeared in the same survey area were phytoplankton, nauplii and copepodites. This ability of the post larval ribbon fish seemed to be closely related to larger size of the egg and the larvae hatched than those of 8 species. Because the ribbon fish spawned smaller number of eggs than those of 8 species, the high ability of feeding at the early post larval stage is very important for their effective survival.The main gut contents of the fish of less than 10mm in anal length were pelagic copepods such as Paracalanus parvus, Paracalanus sp. and Clausocalanus sp. and 10-20mm length were females of Acartia erythraea which made swarms and generally occurred on or slightly above the bottom near the shore. The change of the main food from the pelagic copepods to the epibenthic copepod suggested that the ribbon fish of 10-20mm in anal length shifted their habitats from offshore to the bottom layer near the shore.

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＩＶ 若狭湾西部海域におけるタチウオの食性

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＩＶ 若狭湾西部海域におけるタチウオの食性

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＩＩＩ タチウオの産卵場，産卵習性，分布様式

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＩＩＩ タチウオの産卵場，産卵習性，分布様式

若狭湾西部海域におけるタチウオの漁業生物学的研究 ＩＩ 若狭湾西部海域におけるタチウオの産卵期と性比

This paper deals with the spawning season and sex ration of ribbon fish Trichiurus lepturus in the western Warasa Bay from June, 1981 to February, 1983, which were caught by longline, trolling, set net, purse seine and Danish seine. It was found that the spawning season was from June to September and the highest value fo gonad index of both sexes were shown from July to August. In the early spawning season. maturation of gonad was found in large sized fish more than 300 mm of anal length, and maturation made progress in orde of size. Just before the spawning season, schools of larger fish with the sexratio 1 : 1appeared in this area. In the spawning season. females and males dominated the near shore and offshore, respectively. It was suggested that the difference in the distribution of the sexes was concerned with the mating system.