Iranian Journal of Ichthyology
Volume:8 Issue: 2, Jun 2021

The feeding habits of the endemic cyprinid fish, Hypselobarbus thomassi (Day, 1874) was studied based on the monthly sampling in the Kallada River, Kerala, India from April 2010 to March 2011. Gut contents of 183 fish specimens were analysed and quantified using occurrence and volumetric methods. Analysis of the gut contents showed that semidigested plant matter (22.11%) was the most preferred food item of the fish followed by Bacillariophyceae (19.80%), Chlorophyceae (19.38%), semi-digested animal matter (11.21%), soil particles (9.20%), seeds of plants (6.70%), Cyanophyceae (5.51%) and miscellaneous items (6.08%). The results indicated that H. thomassi is an omnivorous-stenophagic-column feeder. The gastrosomatic index (GaSI) ranged from 3.28-7.33 with an increment from August to November coincides with the spawning season and energy preservation for gonadal development. The information on feeding ecology of H. thomassi, a critically endangered fresh water fish from Western Ghats biodiversity hotspot would be useful towards formulating proper conservation plan for the species in its natural range.

This paper contributed data on otoliths morphometry and their relationships with the size of Periophthalmodon septemradiatus. A total of 135 specimens (86 males and 49 females) were collected from the five sites in branches of the Bassac River, Vietnam. Length, width, and weight of left otoliths were similar to those of the right otoliths. These otolith parameters of did not change with gender, but vary significantly in five sites, reaching the highest point in the upstream of Bassac River in Binh Duc, Long Xuyen, An Giang where fish total length and body weight reached the highest values. The otolith length, width, and weight had strong relationships with fish total length and body weight due to the high value of determination coefficients (r2 ). Among the three dimensions of otoliths, otolith length was the most positive relationship with fish size since r2 of this regression reaches the highest value. The results suggested that otolith dimensions could be used for fish size determination.

The Sefidrud stone loach/Berg loach, Oxynoemacheilus bergianus, is native to the Eurasia and little is known about this species. Some biological characteristics of the species were examined in 358 specimens collected monthly from the Kordan River in Alborz Province, by dip and seine nets during September 2013 to August 2014. The total length range was 32.36-74.36mm (50.95±10.3SD), and the total weight range was 0.31-4.06g (1/12±0.68SD). The maximum age of the specimens, based on otoliths, was 5+ years for females and 4+ years for males. Based on macroscopic gonad observation, the age of maturity was 2+ for females and 1+ for males. Sex ratio was 1M:0.9F and maturation cycle consisted of five stages. The gonadosomatic index indicated that reproduction of the fish in the river system occurred between March and June, with the highest average value of 9.47 for males in April and 13.42 for females in May. Oocyte diameter ranged from 0.15 to 1.33mm, with a mean value of 0.44mm. Absolute fecundity ranged between 360 and 2560 eggs, with a mean of 1130±670 eggs. Absolute fecundity and total length (r2 = 0.58) and total weight (r2 = 0.66) were moderately correlated. The mean relative fecundity was 580±190 eggs per gram of body weight. Therefore, O. bergianus is a species with a premature sexual maturity, high fecundity than that of other loaches and reproduction happen gradually in March to June.

The Northern Bay of Bengal (NBoB) contributes largely towards the fish production of India and its neighboring countries. A pioneering attempt was made to understand temporal variability of the fish assemblage (exclusively to those of fisheries interest) of the NBoB (20°20ʹ–21°30ʹN and 87°30ʹ–89°E) in relation to sea surface temperature (SST) (C), sea surface salinity (SSS), and chlorophyll-a (Chl-a) (g/l) changes. Between 2006 and 2015, the inter-annual variations of SST, SSS, and Chl-a were minor. Seasonal variability of SST, SSS, and Chl-a was observed and a yearly bi-modal peak of Chl-a production was evident. Inter-annual variability of the species dominance (D) was most plausibly explained by the SST*Chl-a (Δ AIC = 0) model. Variation of evenness index (J) was explained most plausibility by the Chl-a (Δ AIC = 0) model. Seasonal variability of SST and Chl-a levels, possibly influence the fish community of the NBoB, therefore, a regular monitoring programme is suggested for understanding the long-term changes of the fish assemblage of the NBoB.

This paper deals with three new distributional records of gobies viz. Amblyeleotris downingi Randall, 1994, Psammogobius biocellatus (Valenciennes, 1837), and Valenciennea muralis (Valenciennes, 1837) from Bangladeshi waters in the northernmost part of the Bay of Bengal. The examined specimens are identified and described by morphomeristic characteristics in addition to DNA barcoding based on mitochondrial COI gene. The COI barcode sequence of Amblyeleotris downingi is submitted for the first time in the GenBank. In addition, an updated checklist of gobies of the country is also compiled in this paper.

The von Bertalanffy growth model (VBGM) is often preferred in the estimation of growth parameters and curves in bony fishes but is rarely evaluated for its accuracy. The aim of this study is to prove that the growth period of some demersal fish species is biphasic. Two growth models (two-phase growth model (TPGM) and VBGM) were used to estimate the growth parameters of the mentioned species and the results were compared by Akaike's Information Criterion (AIC). In 11 cases out of 15 which were tested for different sexes and combined sets, TPGM was determined to reveal more reliable estimations and provides better goodness of fit according to Akaike's Information Criterion (AIC), Δi, and w criteria. It is also found that VBGM tended to yield higher L∞ values and therefore should not be considered as the unique model. It is concluded that the two-phase growth model was the best model for overall cases in this study and it is recommended that comparisons should be performed among different models before the construction of a growth curve for any fish species.

A checklist of marine fishes from the coastal areas of Jakhau and Mandvi, Gulf of Kachchh, west coast of Gujarat, India, was compiled through the fish collection from December 2013 to March 2015. On examination, a total of 20 orders, 47 families and 96 species were recorded. Of these four species were recorded from class Elasmobranchii and 92 species from class Actinopterygii. The Family Carangidae showed species dominance with 10 individuals, while the order Eupercaria is dominated with 18 numbers of species. The checklist contains 10 Not evaluated species, 6 Data deficient species, 68 Least concern species, 5 near-threatened species, 4 Vulnerable, 2 Endangered, and 1 Critically endangered species as per IUCN red list records. Of the total 96 species, the Jakhau sampling site reported 74 species; Mandvi sampling site reported 77 species, while 54 species were reported common from both the sites. Deveximentum indicium (Monkolprasit, 1973) was reported for the first time from Jakhau sampling station of Gulf of Kachchh, Gujarat. Further research is needed for better understanding and conservation of such species. The detailed study of fish habitats in the Kachchh Gulf will provide an insight into diversity and exposures to habitat destruction.

The present study aimed to the evaluation the effects of age, sex and hormonal treatment on the plasma and hematological parameters of Aristichthys nobilis. A total of 80 fish in four treatments, including, four different ages :9-months,1, 2 and 3 years old males and females injected by pituitary gland. Based on the results, age was caused an increases in red blood cell (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), Hemoglobin (Hb) and Haematocrite, neutrophil and lymphocyte percent (P<0.05). Also, there was no significant difference between age groups in WBC and monocytes (P>0.05). The plasma biochemical parameters, including calcium, glucose, cholesterol, triglycerides, protein and phosphorus changed with age and hormonal treatment respectively. The parameters of the hematocrit, hemoglobin, RBC, WBC, MCV, MCH, lymphocyte, calcium, glucose, cholesterol, triglyceride and phosphorus also showed sex dependent differences. But, there was no significant difference between plasma and hematological parameters before and after the hormonal injection in both sexes.