On Saturday the 24th October 2020 the globe will be cerebrating World Fish Migration Day to raise awareness on the importance of free-flowing rivers and the migration of the highly important ichthyofauna (fish). In the wake of an increasingly urbanised and transformed world, the conservation and rehabilitation of natural areas is becoming more and more essential for the survival of the human race as a species. In the context of World Fish Migration Day, the most important natural area of concern would be free flowing rivers. These systems are the freshwater equivalent of a wilderness area, or open spaces as they provide crucial habitat for various aquatic faunal species, as well as support the survival of both the anthropogenic and natural environments in which they preside. Free flowing rivers are systems that are largely unaffected by anthropogenically induced changes to the flow, connectivity and ultimately functionality of the valuable resource. In these systems, water flow, geomorphological processes and faunal migratory routes are unhindered and the rivers are allowed the freedom to dance across their respective flood plains unchecked by human development. This ultimately allows for associated faunal lifecycles, specifically fish, and micro-processes to thrive and provide numerous Ecosystem Services (ESS) to the surrounding anthropogenic and natural environments alike. However, according to research conducted by the World Wildlife Fund (WWF) only one third of the worlds 246 longest rivers (approximately 1,000 km) remain free-flowing, unimpeded by dams, weirs, roads and other barriers. This has proven negative impacts on the overall health and availability of fish species on a global level.
We as a race often take advantage of our position at the top of the food chain, forgetting that the majority of the resource we as mankind depend on come from the lower reaches starting from phytoplankton, which make up approximately 95% of the primary producers on earth. Fish form a pivotal role in the food web at various levels, accounting for a large portion of the essential nutrients and proteins required by humans. According to the Food and Agriculture Organisation (FAO), in 2013 fish accounted for 17 % of the global populations intake of animal protein and 6.7 % of all protein consumed. Based on the human population growth rate of 1.05 % per annum (WorldoMeter, 2020), it is assumed that this figure has increased drastically since then. The dependency of coastal and riverine based areas of poverty on the fish population for their livelihoods and primary source of food should also be highlighted as this is a significant aspect to consider when discussing the importance on free-flowing rivers providing this resource to the less-developed portion of our nations.
How can you help conserve or improve the quality of the environment in which fish migrations occur? Simply living a more environmental conscious lifestyle would be a starting point for all of us- less litter, more recycling, implementing water conservation techniques and lending a helping hand in river and beach clean-ups. Be more attentive to your micro-impact on the receiving environment and help conserve and improve the environment in which these vital migratory processes take place. On a higher level, it is imperative that all developers, environmental specialists, Environmental Assessment Practitioners (EAP) and competent authorities think twice before creating further impeding features within our invaluable river and wetland systems. Consider the no-go option more intently, or implement mitigation measures that will encourage the natural migratory processes to continue in a sustainable manner along-side development. These may include the use of more stormwater infrastructure (i.e. culverts), the development of species-specific fish ladders or aquaculture downstream of development.
On a lighter note, have a great 2020 World Fish Migration Day and remember, “fish are friends not food!” (Finding Nemo, 2003