SPRING INTO THE SUMMER

DAFFODILS are already bursting into flower, the hedgerows are full of hawthorn blossom and, on a warm evening, the first fly hatches are starting to gather. After another mild winter, spring is now well under way and life below the surface is adapting just as it is above. Water temperatures can remain surprisingly low for much longer than above the surface. Dip your hand in the water and you will feel just how much cooler it is. Even now most fisheries will have reached only six or seven degrees centigrade, and this has a distinct effect on the behaviour of the fish.

Changing water temperatures

Cool temperatures mean fish need less food and will soon eat their fill. With appetites suppressed, thanks in part to them carrying a bulk of developing eggs, you can see that hot days do not necessarily guarantee good sport. What is more likely to happen on hot, still days is that the water will begin to stratify. The top foot or two will be warmed by the sun and can become several degrees warmer than the water below. Normally these layers will break down as the sun sinks below the horizon, forming on the next warm day. Carp are the most obvious fish to make the most of this warm surface water and will often bask near the top. Their dark backs will also absorb the suns energy directly, giving them a feeling of warmth. With the carp spending much of the time up in the water, it is no surprise that zigging can be such an effective method at this time of the year. Most stillwaters will become much clearer over the winter months, primarily because the suspended algae significantly drops. As the water warms these single-celled plants begin to divide once more and their numbers can rapidly build up. First, species of diatoms which give the water a brown hue, come to dominate, but in the coming weeks the algae overtake them and the water turns green as the first algal bloom on the year takes hold. There is a similar succession taking place among the aquatic plants. First it is the fastgrowing filamentous algae that will take hold and often coat the lakebed in a sludgy film, before the stemmed plants, such as Canadian Pondweed, begin to grow and eventually outcompete the simpler plants. Water lilies initially produce submerged leaves that look almost like underwater lettuce before they send up longer stems that eventually reach the surface and carry the floating leaves.

On the cusp of a new season, changes are afoot above and below water “Carp are the most obvious fish to make the most of warm surface water”