Time scales for fish
How did experts determine that the maximum a Golden mahseer ever lived was 50 years? The subject came up recently when keen angler, Major Sanjay S Dadhwal (retd), hooked a mahseer from the Gobind Sagar. Following an earlier request from Prof MS Johal, who is a fisheries researcher at Panjab University (PU), Chandigarh, Major Dadhwal duly removed a few scales, freed the mahseer, and couriered the scales to the PU. Writes Vikram jit SinghUpdated: Nov 08, 2014 23:26 IST
A GREEN DIWALI
It was heartening to note how many children had turned votaries of a 'Green Diwali' this year. Never mind if newspapers still painted a gloomy picture on Diwali pollution the next day! And, not all kids were merely parroting a parental or a teacher's script. There was a genuine feeling amongst kids to usher in a non-obnoxious celebration limited to candles, 'phuljharis' and a few 'anars'. Kid columns in tricity newspapers also reflect this as many scrawls, paintings and drawings stem from an innocent concern for saving our planet from ourselves!
Wandering in the jungles in late autumn also affords such celebratory spectacles. I was struck by the profusion of petite pink flowers blooming without a worry from low shrubs. These shrubs run astride jungle paths that meander merrily amid a greenery that is steadily acquiring pastels and hues of khakis and drab brown. If the flowers remind one of tiny 'diyas' whose wicker is lit by a mellowing winter sunshine, the cloud of small, creamish Rice Leaffolder moths that arise when the shrubs are ruffled bring to mind the exuberance of a releasing 'anar'. (These moths are also seen clinging to verandah ceilings and are eyed greedily by lizards braving the deepening chill. Lizards tuck into these moths to build fat reserves for hibernation.)
Charmed by these pink delights (which also invite comparison with elegantly painted fingernails!), I sought the expertise of botanist Dr Nidhan Singh. ``This plant is Peristrophe paniculata, a native of South-east Asia and Malaysia and basically a weed. It has spread through the sub-continent. The plant is actually a multi-branched herb but gives a shrub-like appearance in aggregation. Though this belongs to Acanthaceae-the family of 'Vasaka' (Adhatoda vasica) which is a valuable medicinal plant- this particular shrub is not valued for its medicinal properties," said Dr Singh.
TIME SCALES FOR FISH
How did experts determine that the maximum a Golden mahseer ever lived was 50 years? The subject came up recently when keen angler, Major Sanjay S Dadhwal (retd), hooked a mahseer from the Gobind Sagar. Following an earlier request from Prof MS Johal, who is a fisheries researcher at Panjab University (PU), Chandigarh, Major Dadhwal duly removed a few scales, freed the mahseer, and couriered the scales to the PU. Major Dadhwal also spread the word among fellow anglers to similarly dispatch scales to the PU so as to further research in fish biodiversity.
After studying scales with specialised equipment, Prof Johal concluded that Major Dadhwal's mahseer had completed 11 years. "Scales form the protective covering of most fish (excluding Mulee, Singhara and Singhi). The number of scales is species-specific and continues to grow through a fish's life. Scales record all events in a fish's life such as unfavourable conditions, high fish density, disease and change in water quality. In this region, almost all fish start breeding during the first year of their life and the number of breeding or spawning marks corresponds with the age of the fish in years. Due to some reasons, such as failure of the monsoon (which otherwise acts as a trigger for spawning), fish do not record this mark. Fish biologists can check for this missing mark by employing appropriate techniques and statistical parameters,'' explains Prof Johal.
Photo Caption:Maj. Dadhwal with the 11-year-old mahseer. Photo Credits: AMIT DHAWAN
"On the basis of earlier data and records of mahseer from Gobind Sagar, the length of Major Dadhwal's fish should be more than 84 cm. Major Dadhwal informed me that the length was around 90cm. There is no significant difference between observed length, and length as estimated from earlier data. In general, the overall growth rate of Major Dadhwal's fish has decreased (15 %) indicating that Gobind Sagar has less food for mahseer as compared to earlier years," said Prof Johal.
GRAINS FROM GUTS
Like unashamed guests who come early and stay late, the vulnerable species, Yellow-eyed pigeon, has descended on Tal Chhapar wildlife sanctuary in Churu, Rajasthan, in an estimated number of 2,000 this autumn. The pigeons, which migrate from Central Asia, have got so comfortable at Tal Chhapar that each year they lengthen their sojourn here! This bird is also the lost pigeon of the Punjab. Colloquially named the 'Salara' in Punjab, the pigeon would arrive in thousands till the Green Revolution robbed it of a diet of pulses/mustard. It was also a favoured game bird for shikaris.
Photo caption: Yellow-eyed pigeons at Tal Chhapar.Photo credits:SS POONIA
Currently, this pigeon also migrates to Jorbeer carcass dump and other spots near Bikaner. Ornithologist Dr Vibhu Prakash has observed these pigeons feeding on grains spilling out of the guts of rotting carcasses. Due to multiple threats, no more than 20,000 mature individuals survive globally.
First Published: Nov 08, 2014 22:28 IST