Dr Roger Munro reveals the cycles and rhythms dictating fish behaviour and explains how mastering these biological clocks will super-charge your catches
One summer, many years ago, while fishing alone on Mumbles pier, I cast my bait out on two Daiwa Sandstorm bass rods just as the neap tide reached bottom water. Apart from a couple of dogfish, which I caught during the first two hours of the flooding tide, my efforts were fruitless. An hour after low water I was joined by an elderly angler who set up just one rod with a single 1/0 hook attached to a 12-inch-long flowing snood sitting just above a 1oz tear-drop sinker. He then promptly sat on one of the available benches and did nothing. Two hours later he was still sitting there – doing nothing. Intrigued by his long spell of inactivity, I casually asked him if he was going to do any fishing. He looked at his watch and said, “I’ll give it another five minutes.” True to his word, he baited his single hook with one king ragworm and dropped it between the pier stanchion supports. During the next two hours he caught red mullet, grey mullet, trigger fish, bass, dogfish, black bream, pollack, dragonet, corkwing wrasse, pouting and a three-bearded rockling, all with king ragworm bait. Two hours after he started fishing (an hour before top water) he stopped, packed up and went home. Impressed by his catch-rate, I followed his example the following day. I didn’t quite match his tally but I did catch several fish all within the same two-hour period. Although I fished the last hour of the flood and almost all of the ebb, I only managed to catch one school bass during this period. This remarkable experience reinforced my long-held belief that fish forage in response to set feeding cycles governed by an in-built biological clock.
They also have well-recognised biological clocks for spawning and mating. During summer nights in the 1980s, residents of houseboats in San Francisco Bay were subjected to a mysterious humming noise which, just like clockwork, started suddenly during late evenings and stopped just as abruptly in the mornings. The sound was so loud that it drowned out conversations and disrupted sleep. This noise was caused by male Plainfin Midshipman fish singing at nights to attract mates.
ROCK HOPPING GOBIES
Although feeding and spawning cycles are crucial in governing a fish’s behaviour, light and tide are also two important factors acting to help learning behaviour in many species. One of the best recognised of these behaviours involves the impressive escape response in rock-pool gobies. When threatened, the gobies jump from their pool into a neighbouring one. The accuracy
