Reproductive biology of Puntius denisonii, an endemic and threatened aquarium fish of the Western Ghats and its implications for conservation

Abstract

This study presents fundamental information on the reproductive biology of Puntius denisonii, an endemic and threatened aquarium fish of the Western Ghats Hotspot. Results are based on the observations from three river systems, Chandragiri, Valapattannam and Chaliyar. Maximum observed total length in P. denisonii was 162mm and 132mm for males and females, respectively. Males attained sexual maturity at a lower size than females with mean size at first maturity determined as 85.33±1.52 mm for males and 95.66±1.15 mm for females. Puntius denisonii spawned from October to March with minor differences in the peak breeding months between the three river systems, which were studied. Sex ratio deviated significantly from 1:1 and was skewed in favour of males. Absolute fecundity varied from 376 (fish of 102mm total length) to 1098 (fish of 106mm total length) eggs. Currently, the closed seasons for P. denisonii have been put in place during June, July and October based on the (mis)assumption that the species breeds during these three months. However, the results of the present study have helped us to understand more about the reproductive biology of the species so as to recommend more appropriate seasonal closures. The months from October until March need to be designated as a closed season for protecting the breeding population of P. denisonii.

Species Distribution Modeling And Assessment of Environmental Drivers Responsible To Distribution And Preferred Niche of Critically Endangered Endemic Ornamental Freshwater Fish Species of The Genus Sahyadria

“…Similarly, 'Solar Radiation' in April, 'Temperature Annual Range', 'Temperature Seasonality' and 'Logarithmic of the accumulation' are the important environmental factors in de ning the ecological niche of S. chalakkudiensis. The Jackknife test further provide more information about these predictors suggesting that 'Temperature' and 'Solar radiation' in January and December are the limiting factors in distribution of S. denisonii because these months are breeding periods of this species with peak Gonado Somatic Index (GSI) (Solomon et al, 2011). Similarly, 'Solar radiation' and 'Temperature' in January as well as February are critical for distribution of S. chalakkudiensis associated with breeding of this species during these months.…”

Diversity, distribution, and conservation status of fish species in Kallar Stream, Achankovil River, Western Ghats of Kerala, India

“…Though a large share of the population of the species including threatened ones are protected within the reserve forest area, destructive fishing practices employed by the local people outside the forest area targeting mainly the migratory and nocturnal fish species such as the catadromous anguillid eels, spiny eels, and catfishes may certainly result in disruption of proper recruitment to the stock and subsequent population decline. Moreover, this type of fishing practice may have a serious negative impact on the breeding and recruitment of non-targeted species; as the majority of the hill stream fishes including most of the threatened fishes are known to breed during the post monsoon months of November to February (Ali & Prasad 2007;Thampy 2009;Solomon et al 2011). Hence, there is an urgent need for declaring a fishing ban or closed season during these months for protecting the breeding populations and ensure proper recruitment.…”

Reproductive biology of the endemic cyprinid fishHypselobarbus thomassi(Day, 1874) from Kallada River in the Western Ghats, India

“…Knowledge of fish fecundity had much relevance to study the population dynamics and successful management and exploitation of fish stocks (Alam & Das, 1996). The fecundity of H. thomassi is similar to that of some other cyprinid species ie., 26–302 oocytes for Puntius vittatus (Ibrahim, 1957), 305–1168 oocytes for Barilius bendelisis (Desai & Karamchandani, 1967), 692–1392 oocytes for Glyptothorax kashmirensis (Kaul, 1994), 800–2126 oocytes for Nemacheilus triangularis (Ritakumari & Nair, 1978), 376 to 1,098 oocytes for Sahyadria denisonii (Simmy et al., 2011) and 426–823 oocytes for Puntius pookodensis (Seena, Jose, Annamercy, Eapen, & Nair, 2012). The fecundity of fishes varied between species, stocks, water temperature, environmental condition and food supply and its quantity (Bromage, Hardiman, Jones, Springate, & Bye, 1990; Johnson et al., 1997).…”