|Scientific Name:||Puntius denisonii|
|Species Authority:||(Day, 1865)|
Labeo denisonii Day, 1865
|Taxonomic Notes:||Puntius denisonii was described by Day (1865) from Mundakkayam, Kerala, southern India.|
|Red List Category & Criteria:||Endangered A2acde+3cde; B2ab(iii) ver 3.1|
|Assessor/s:||Ali, A., Raghavan, R. & Dahanukar, N.|
|Reviewer/s:||Gopalakrishnan, A., Rema Devi, K.R., Shaji, C.P., Arunachalam, M., Johnson, J.A., Vidyadhar, A., Rahul, K., Krishna , K.K. & Molur, S.|
|Contributor/s:||Molur, S., Bogutskaya, N. & Rema Devi, K.R.|
Puntius denisonii has been assessed as Endangered as populations have declined by more than 50% in the recent past due to indiscriminate exploitation for the international aquarium pet trade. These declines are expected to continue in the foreseeable future unless local management plans, as well as national and international legislations are created and implemented. The species also has a restricted range with an area of occupancy of less than 300 km² with continuing decline in quality of key habitats.
Puntius denisonii is endemic to the Western Ghats where it occurs as fragmented populations in the states of Kerala and Karnataka (Raghavan et al. 2010, Prasad et al. 2008). Known from the rivers Chandragiri (Biju 2005, Kurup et al. 2004), Valapatanam (Biju 2005), Karyangod (Kurup and Radhakrishnan 2006), Chaliyar (Shaji et al. 2000), Kuttiyadi (R. Raghavan and A. Ali pers.obs.), Bharatapuzha (Kurup et al. 2004), Sullya (R. Raghavan and A. Ali pers.comm), Kuppam, Iritti, Anjarakandipuzha and Bhavani River in Chavadiar (Mercy 2010; A. Gopalakrishnan pers. comm.).
Populations have also been reported from Chalakudi (Radhakrishnan and Kurup 2006), Periyar (Thomas 2004), Manimala (Thomas 2004), Achenkovil (Kurup et al. 2004), and Pampa (Thomas 2004). These localities however represent P. chalakkudiensis (A. Gopalakrishnan pers. comm.).
Native:India (Karnataka, Kerala)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The total population of P. denisonii is unknown. However the species is considered to be rare (Radhakrishnan and Kurup 2006, Kurup and Radhakrishnan 2006). Studies conducted at Cochin University of Science and Technology have indicated that populations of P. denisonii has declined at a rate of 70% at key collection sites (Kurup and Radhakrishnan 2006). A recent ongoing study by the Conservation Research Group, St. Albert's College, Kochi has observed that the species is overfished in Valapatanam River (exploitation rate E = 0.596) in Kerala (Raghavan 2010). In another completed study by MPEDA, based on the secondary data collected from the collectors, the catch by the collectors increased from 2003 to 2007 in Valapattanam, Kuttiyadi, Chalayar and Chandragiri rivers (Mercy and Malika 2010).|
|Habitat and Ecology:||P. denisonii is a stream dwelling fish with an affinity towards rocky pools, edges with thick overhanging vegetation along its banks (Radhakrishnan 2006; Raghavan et al. 2009). However they have also been observed from a wide variety of riverine habitats including run, glide and riffles with sand, gravel, cobbles and boulders as substrates (Biju 2005). They are gregarious and often appear in shoals. The species is known to spawn during the North East Monsoon in the months of November-January (Manoj et al. 2010; R. Raghavan and A. Ali pers. obs.).|
|Major Threat(s):||Collection for the international aquarium pet trade is the single major threat to P. denisonii (Mittal 2009, Prasad et al. 2007). Harvest of 'yet to be mature' juveniles as well as brooders is a major concern as the fishery is unregulated and 'open access'. In addition, there is an on-going decline in habitat quality at prime habitats of P. denisonii due to pollution from plantations as well as domestic sources. Destructive fishing for larger food fish using dynamites and plant poisons also affect P. denisonii as they share habitats with the larger cyprinids.|
To regulate the harvest and trade of this cyprinid, the Government of Kerala (India) has initiated management plans including fixing total allowable catch (TAC), restrictions on gear size, closed seasons. There are also plans to demarcate certain key P. denisonii habitats as sanctuaries and no take zones (Mittal 2009). Although the captive breeding technology for this species has been developed by both researchers and hobbyists (Manoj et al. 2010; Mathew 2008; Mercy et al. 2010), commercial scale operations have not started. There are reports that P. denisonii is being captive bred in Indonesia and Singapore and exported (Mittal 2009), but the impacts of such operations on the collection and exports from India is yet to be understood.
Life history studies on the species have been conducted by Radhakrishnan and Kurup (2008) and Harikrishnan et al. (2008) studied the population dynamics in \the rivers of Kerala. Distinct genetic stocks identified in Chandragiri, Valapattanam and Chaliyar rivers (Lijo unpublished PhD thesis, NBFGR).
A species specific conservation plan requires urgent attention.
|Citation:||Ali, A., Raghavan, R. & Dahanukar, N. 2011. Puntius denisonii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 20 April 2014.|
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