Compositional trends of fisheries in the River Ganges, India

Abstract

Monthly surveys of local fisheries from five principal landing sites on the River Ganges at Bhagalpur, India, were conducted from 2001 to 2007. Fishes of a range of sizes with mostly periodic-type life-history strategies, including many catfishes and carps, dominated the catch. Average annual yield (total mean monthly catch in units of biomass) was highly variable but trended downward during the study. Statistical ordination revealed associations between assemblage composition and hydrological seasons. Overall yields in this reach of the River Ganges tended to be greatest when the annual flood pulse was sustained longer. Patterns of average stock yields and inter-annual variability of yields were associated with species life-history strategies, with the most abundant and least variable species having periodic-type strategies of seasonal spawning, high fecundity, small eggs and no parental care. Although not appearing to have declined precipitously during the study, many stocks in this stretch of the River Ganges, including those of the largest and most valuable species, nonetheless seemed to remain below historical yield levels because of multiple impacts, including chronic intense fishing and other anthropogenic impacts.K E Y W O R D S : assemblage structure, fish community, flood pulse, floodplain, life-history strategy.

Identifying potential causes of fish declines through local ecological knowledge of fishers in the Ganga River, eastern Bihar, India

“…In general, information on spawning season, reproductive strategies, habitat associations and other ecological data from LEK matched closely with published literature on freshwater fish life histories (Montana et al, ; Qasim & Qayyum, ; Talwar & Jhingran, ; Vass, Mondal, Samanta, Suresh, & Katiha, ; Vass, Tyagi, Singh, & Pathak, ; Welcomme, Winemiller, & Cowx, ; Winemiller, ; Zeug & Winemiller, ). This information was used to find explanations for causes of declines fishers attributed to different species.…”

“…An adverse outcome of conflicts has been distress-induced labour migration of fishers to distant regions, many having by now permanently exited the dangerous setting (Kelkar, 2018). The department's association with fishers has existed since 1999 through long-term fisheries monitoring and research conducted in conservation programmes for endangered Ganges river dolphins and other biodiversity (Choudhary et al, 2015;Choudhary, Smith, Dey, Dey, & Prakash, 2006;Montana, Choudhary, Dey, & Winemiller, 2011). Documenting long-term F I G U R E 1 Map showing locations of fishing settlements in the Bhagalpur district, Bihar, India, from which local ecological knowledge (LEK) data were compiled for our study [Colour figure can be viewed at wileyonlinelibrary.com] insights from local ecological knowledge (LEK) is thus important to place environmental and social change in perspective, for the management of fisheries in the Ganga river-floodplain ecosystem.…”

Influence of seasons, habitat sanctuaries, gears and environmental variables on the catches of hilsa shad (Tenualosa ilisha) in Bangladesh waters

“…This shower slightly increasing trend and 2006 and 2007 pH level from 7.3 to 7.5 was quite stable. In the present study, the pH tended to be higher than those reported by Montana (2011), which was suitable for breeding and nursery of hilsa. Overall, the environmental variables in the present study was found to be consistent with those reported by several researchers (Sharif 2017a, b;Montana 2011;Ahsan 2014).…”

“…70 -8.30 and 7.9 -8.40 for breeding and nursery activities, respectively, while the salinity was <0.1 ppt. Montana (2011) found the pH level of 6.5 in 2003 summer to 7.5 in summer, monsoon and winter at the River Ganges at Bhagalpur, India. This shower slightly increasing trend and 2006 and 2007 pH level from 7.3 to 7.5 was quite stable.…”

Water Quality Influences on Fish Occurrences in Sungai Pahang, Maran District, Pahang, Malaysia

“…The range of ammonia, nitrate, phosphate, TSS, temperature and DO readings were considered high throughout the study period. According to Montana et al (2011) and Singh (2007), this phenomenon happened due to seasonal response to watershed geology, topography, vegetation and hydrology. As observed in our study, during the rainy season, for example for TSS, the range was very high because of the high concentration of sediments carried by the river.…”