Why does this matter? Aquaculture depends on fishmeal and fish oil made by grinding down wild-caught fish such as anchovies and sardines to use as feed. Rising ocean temperatures are disrupting those species, with pelagic fish including jack mackerel and anchovy moving south in search of cooler water, shifting to greater depths and showing irregular migration patterns. Aquaculture produced 103 million mt of aquatic animals in 2024, 53% of total aquatic animal production and virtually all of the industry’s growth since the late 1980s, while capture fisheries have plateaued at around 92 million mt.

How does El Nino work? – El Nino weakens coastal upwelling, the process that normally pulls deep, nutrient-rich water to the surface to feed the plankton at the base of the marine food web. With less upwelling, biological productivity drops and contracts closer to shore. As a result, fish move to find better conditions elsewhere. Mark Gold, director of California Cooperative Oceanic Fisheries Investigations (CalCOFI), expects that if the current El Nino follows a similar pattern to 2014-2016, anchovy numbers could stay strong while sardine abundance stays low. Some species boom, others collapse, and the pattern is difficult to predict in advance.

A historic event, not a one-off – World Meteorological Organization (WMO) Secretary-General Celeste Saulo has said the world needs to prepare for a potentially strong El Nino, noting the most recent event in 2023-24 was among the five strongest on record. In Peru, which typically supplies around 20% of the world’s fishmeal, fishing in the North-Central anchovy season was suspended in June after boats had caught only 25% of the season’s total permitted quota, leaving most of the season’s planned catch uncaught.

The International Fishmeal and Fish Oil Organisation (IFFO) has said El Nino conditions continue to strengthen and are forecast to persist into early 2027, with a new scientific monitoring operation now assessing anchovy distribution to determine whether fishing can resume at all. The longer a stronger El Nino lasts, the longer producers go without knowing where their catch will be. For a supply chain built on catching specific species in specific places, that kind of unpredictability leaves producers with a choice: absorb the uncertainty or turn to feed that was never tied to the ocean in the first place.

Feed sources insulated from the ocean – Producers are already working to remove that risk. Enthos, for example, produces protein and oil from black soldier fly larvae reared on organic waste, a source of aquaculture feed that doesn’t rely on anchovies, sardines or any other wild-caught fish. Because its feedstock has no connection to wild fish stocks, ocean temperatures or migration patterns, an insect-based feed input is unaffected by what pelagic species do. As a historically strong El Nino makes the ocean less predictable, that independence from wild catch becomes even more valuable.

The bottom line – Aquaculture’s growth has been built on the assumption of a predictable ocean. That assumption no longer holds. Feed sources that don’t depend on the ocean’s behaviour aren’t a sustainability add-on anymore. They are protection against a supply shock still to come.