Sitting at the end of the wooden jetty, I watch the line of longboats ease out of the harbour towards the start of the race. Even close to the water, the heat is intense, and I don’t envy the crews – each with four rowers and a cox – who will tackle this triangular open-sea course of about three miles in the baking August sun. They are an amiable bunch who have travelled with their longboats, all built to the same basic design, from coastal settlements across west Wales to compete in the Aberystwyth leg of the summer series of races. The support for the exhausted crews at the finish line, the mouth of the harbour, is enthusiastically vocal. Many of the folk here know each other well and the sport seems more collaborative than competitive – often loaning gear, boats or even crew members to other teams. Needing shade, I head back towards town, pausing to chat with a friend who asks if I had seen the otter that was spotted weaving between the moored fishing boats. I had missed it, of course, but resolved to return on a day when there is less activity in the river. Some days later, I am back at the harbour. Heading out determined to see an elusive mammal such as an otter is clearly an act of folly, so I tell myself it is just a walk – but I keep my eyes open nonetheless. The stone quayside opposite the raft of fishing boats provides a good vantage point, and I sit in the sunshine with my feet dangling over the wall. It is much cooler now, with a hint of the turning season in the softening light. A cormorant preens itself on the top of a marker post, gulls stand around on the edge of the weed patches waiting for the tide to fall, but of the otter there is no sign – except that everywhere I look I imagine I can see one. Each puff of wind disturbing the water, every swirl of the current or rise and fall of weed at the edge of the stream is for an instant a moving, living creature. With a sigh, I haul myself up and continue my walk. Next time, I tell myself, next time. Country diary is on Twitter/X at @gdncountrydiary Under the Changing Skies: The Best of the Guardian’s Country Diary, 2018-2024 (Guardian Faber) is published on 26 September; pre-order now at the guardianbookshop.com and get a 20% discount