First week of the New Year, and in the small hatchery that is supplied with spring water, the Brown Trout eggs that were stripped in November have hatched. The 5mm orange eggs sit in baskets in a trough of running water. Because the spring water is a constant 10 degrees it is possible to estimate within a few days when the eggs will hatch, the colder the water the longer the eggs take to hatch. At 10 degrees the eggs hatch out around Christmas time, the newly hatched elevens lie on the bottom of the tank absorbing their yolk sac for around 2 weeks before swimming up to the water’s surface and feeding like normal fish.
This week one of my daily tasks has been to clean up the small transparent egg shells that litter the tank and any dead eggs or alevins, I do this with a pipette and siphon, gently moving the alevins around by blowing the pipette and hoovering up any shells or dead alevins with the siphon. Because the fertilisation is carried out artificially, and the eggs receive a higher level of care than in a wild environment many eggs hatch that would not normally make it in the wild. It is not uncommon to see two headed or two tailed alevins; many have deformed spines some enlarged heads. These genetic deformities invariably die in time, as they are unable to compete successfully for food or shelter.
The spring water in the hatchery is “old water” drawn from the chalk aquifer it has been filtered over time, is alkali and can be depleted in dissolved Oxygen and high in dissolved Nitrogen. This can be a problem to fish raised on spring water in a hatchery. Similar to the “bends” bubbles of Nitrogen form inside the alevin or fry, showing as a dot on the fry’s head or an air bubble inside the yolk sac. So far this year this has not been a problem, but occasionally in previous years I have found it necessary to “bash” the water around as it falls into the tank, mixing it with the air to replace the dissolved Nitrogen with Dissolved Oxygen.
As I write it is raining heavily, the river certainly needs the rain. To date we have had a relatively dry winter, we need lots through January, February and early March before everything else starts to take a drink. The aquifers are below what you would expect for this time of year. A wet winter can have a significant effect on mid to late season fishing when the river is solely maintained by water from the aquifers. Weed growth and fly life are far more abundant after a wet winter and fishing much the better for it.
Tomorrow we have our third shoot of the season, my employer’s children, grand children and friends will shoot, my friends and family will beat. By early afternoon we will have a bag of anywhere between 6 and 60, chiefly comprising pheasant and partridge with the odd duck, goose, snipe, woodcock, and pigeon. We will all sit down together in my employer’s house, Guns and Beaters, and have lunch all afternoon. It’s a great days shooting enjoyed by all who take part..The backend of this week has been spent preparing for tomorrows shoot, and clearing my employer’s house of Christmas decorations.