Reproductive environment of the decreasing Indian river shad in Asian inland waters: disentangling the climate change and indiscriminative fishing threats
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Title |
Reproductive environment of the decreasing Indian river shad in Asian inland waters: disentangling the climate change and indiscriminative fishing threats
Not Available |
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Creator |
Uttam Kumar Sarkar
Koushik Roy Gunjan Karnatak Malay Naskar Mishal Puthiyottil Snigdha Baksi Lianthuamluaia Lianthuamluaia Suman Kumari Bandana Das Ghosh Basanta Kumar Das |
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Subject |
Breeding thresholds
Breeding phenology Mesh size Pre-spawning girth Gudusia chapra Freshwater clupeids |
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Description |
Not Available
The regional climate has significantly warmed with erratically declining annual rainfall and intensified downpour within a narrower span of monsoon months, which led to an increased trophic state (≈algae) in most inland waters. Freshwater clupeids vitally control the aquatic food chain by grazing on algae. Despite increasing food availability, IUCN Red List® revealed 16 freshwater clupeids with a decreasing population trend. We investigated one such species’ reproductive dependencies, Gudusia chapra (Indian river shad), in the lower Gangetic drainage (India) under a mixed context of climate change and overfishing. Monthly rainfall (≥ 60–100 mm) and water temperature (≥ 31–32 °C) are key breeding cues for females. The regional climate seems inclined to fulfill these through the significant part of the breeding season, and indeed the species has maintained consistent breeding phenology over 20 years. Other breeding thresholds relevant to fishing include size at first maturity (≥ 6.8 cm; reduced by ~ 25–36%) and pre-spawning girth (Girthspawn50 ≥ 7 cm; first record). Girthspawn50 is a proxy of the minimum mesh size requirement of fishing nets to allow safe passage of “gravid” females ( + 22%bulged abdomen) and breed. The operational fishing nets (3–10 cm mesh) probably have been indulged in indiscriminative fishing of gravid females for generations. Under a favorably changing climate and food availability, existing evidence suggests a fishery-induced evolution in regional females (to circumvent such mesh sizes) through earlier maturation/puberty at smaller sizes. It could be an early warning sign of population collapse (smaller females → lessening fecundity → fewer offspring). Overfishing seemed to be a bigger threat than climate change. Not Available |
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Date |
2021-08-11T06:30:45Z
2021-08-11T06:30:45Z 2021-02-14 |
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Type |
Research Paper
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Identifier |
Sarkar, U. K., Roy, K., Karnatak, G., Naskar, M., Puthiyottil, M., Baksi, S., ... & Das, B. K. (2021). Reproductive environment of the decreasing Indian river shad in Asian inland waters: disentangling the climate change and indiscriminative fishing threats. Environmental Science and Pollution Research, 28(23), 30207-30218.
Not Available http://krishi.icar.gov.in/jspui/handle/123456789/54639 |
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Language |
English
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Relation |
Not Available;
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Publisher |
Springer
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