Idioms are phrases that convey more than their literal meaning, occasionally drawing from real-world phenomena.
In this series, we explore a selection of idioms through the lens of research at the Institute for the Oceans and Fisheries at the University of British Columbia, uncovering if and how they connect with the natural world and scientific concepts.
Ships passing in the night
This idiom refers to fleeting or unnoticed encounters. In the world of illegal fishing, however, it takes on a much more literal and troubling meaning.
While fishing on the High Seas remains essentially unregulated, coastal nations have exclusive economic zones — extending 200 nautical miles from their shorelines — where only they have the right to catch marine resources. Unfortunately, monitoring these zones is challenging in many countries, especially, many in the Global South, contributing to the growing problem of illegal fishing.
“Illegal fishing vessels often take advantage of the cover of night, switching off their lights to avoid detection,” explains Dr. Rashid Sumaila, University Killam Professor at the Institute for the Oceans and Fisheries and the School of Public Policy and Global Affairs (SPPGA). Small vessels often literally pass by larger vessels to collect the illegally caught fish and transport it to shore for sale.
Organizations like Global Fishing Watch are using satellite technology to bring greater transparency to human activity at sea. But technology alone isn’t enough. “Legal systems must work hand-in-hand with environmental monitoring efforts to strengthen surveillance,” Sumaila says.
Stuffed to the gills
This idiom refers to someone who has eaten far too much — though it doesn’t hold up under biological scrutiny when it comes to fish.
“Gills on a fish line up anatomically to where the neck is on a human,” explains Dr. Daniel Pauly, University Killam Professor at the Institute for the Oceans and Fisheries. “When someone says they’re full ‘to the gills,’ it’s like saying they’re stuffed all the way up to their neck.”
Although unrelated to food consumption in fish, gills play a vital role in supplying the oxygen fish need to grow. According to Pauly’s Gill-Oxygen Limitation Theory, gills, which are two-dimensional surfaces, can’t keep up with the oxygen demands of a fish’s growing three-dimensional body. As a result, “fish growth is constrained by the surface area of their gills,” Pauly explains.
As climate change warms the oceans, less oxygen is available for fish to invest in growth, causing them to stop growing at smaller sizes. Additionally, some fish will no longer be able to ‘stuff themselves to the gills’ with food as the waters become too warm in lower latitude regions — prompting many species to shift their ranges toward the poles.
Once in a blue moon
This idiom refers to something rare, and the word choice is especially fitting given the somewhat infrequent yet predictable tidal patterns influenced by the moon.
“The lowest lows and the highest highs occur around the new moon and full moon,” explains Dr. Chris Harley, Professor at the Institute for the Oceans and Fisheries and Department of Zoology. As a result, there are extreme tides about every 2 weeks, and exceptionally low tides when new or full moons aligns with solstices.
Variability in the timing of low tides influences the thermal stress experienced by intertidal plants and animals. In the Salish Sea, extreme low tides often occur around midday during summer. As temperatures continue to rise with climate change, extreme low tides may push some species beyond their thermal limits, increasing the risk of localized extinctions. The 2021 heatwave saw widespread die-offs of intertidal life and was especially severe because it coincided with extremely low tides.
Also, rarer lunar cycles are worthy of this idiom. “There is an 18.6-year cycle in the moon’s orbit, with the lowest summer low tides occurring every 18-19 years,” says Harley. “So, we’ll have some extreme lows this summer.”