Isaac Szabo's Image

Isaac Szabo (USA) witnesses the abundance of life in a freshwater stream as a river chub’s nest attracts other species.

Lying in a stream in western Virginia, USA, Isaac could just about make out an orange glow. To his delight, as he approached, colourful fish appeared out of the haze.

During spring spawning, male river chubs carry rocks and pebbles sometimes as far as 10 metres to form a mound among which the female can lay her eggs, sheltered from currents and predators.

This male’s nest-building diligence had not gone unnoticed. An array of other fish species joined to add their eggs to the perfected site, potentially increasing their collective chance of survival.

In instances like this, the river chub acts as a keystone species - an organism that helps to hold the ecosystem together and support biodiversity. It does just this by providing important nesting opportunities for other freshwater fish.