Ocean Idioms

This idiom means to go unnoticed or undealt with — but when a humpback whale becomes entangled in aquaculture facilities, the problem is impossible to ignore.

As humpback whales have returned in growing numbers to feed in the inshore waters of British Columbia (BC), their presence increasingly overlaps with marine fish farms. From 2008 to 2021, eight humpbacks were found entangled in aquaculture facilities. Five were successfully freed through human intervention, while three died. Most were young whales, still learning to navigate their environment, and were typically caught in predator nets or anchor lines.

“Humpback entanglements at aquaculture sites accounted for less than six percent of reported entanglement cases in BC, but without human intervention, all eight entanglements would have likely been fatal,” said Dr. Andrew Trites, Director of the Marine Mammal Research Unit at the Institute for the Oceans and Fisheries. “Allowing humpback whales to slip through the net is not an option—their survival relies on us reducing their risk of becoming entangled and responding quickly and collaboratively to free them when incidents do occur.”

Plenty of fish in the sea

This idiom is often used to suggest that there are many other options out there, but in a literal sense, this idiom does not ring true for the world’s fish stocks.

Historically, global estimates of fish catches relied on incomplete data sources, leaving major gaps in our understanding of the true scale of extractions from the ocean. “We undertook the task of counting the world’s marine catches for our 2016 Global Atlas of Marine Fisheries and freely available database,” said Dr. Daniel Pauly, University Killam Professor at the Institute for the Oceans and Fisheries and Principal Investigator of the Sea Around Us. By reconstructing estimated catches from 1950 to the near-present across 273 Exclusive Economic Zones, “we show that not only is the global catch much greater than previously reported, but it’s also been declining at a much quicker rate.”

Climate change and overfishing are the leading drivers of this decline. “Through unselective fishing gear such as bottom trawlers, we continue to extract young fish that haven’t had the opportunity to reproduce,” says Dr. Pauly. “At the rate we are going, the idiom will soon change to: ‘There are no fish in the sea.’”

Fish out of water

This idiom refers to someone who is out of place in unfamiliar surroundings. While preserved fish specimens in museums, which are literally out of water, might seem out of place, they actually play an important role in research.

Length-weight relationships (LWR) help scientists estimate species abundance to assess ecosystem health and support fisheries management. However, calculating LWR usually requires many specimens of the same species, which isn’t possible for rare or deep-sea fish. “We proposed another approach to estimate LWR: using preserved museum specimens of fish,” said Dr. Nicolas Bailly, Biodiversity Informatics Specialist in the Sea Around Us at the Institute for the Oceans and Fisheries (IOF) and Fish Curatorial Assistant at the Beaty Biodiversity Museum (BBM).

The BBM houses over 300,000 preserved fish specimens, primarily from British Columbia but also from around the world, with some collected over 100 years ago. In a collaboration between the IOF and BBM, researchers measured around 300 specimens from species that previously lacked LWR data. “We are aware of the biases involved with this method,” says Dr. Bailly. “But we showed that, with some verification, these estimates are reliable enough to support ecological and fisheries research.”

A deep dive

This idiom refers to an in-depth examination of a subject — and when it comes to the role of scuba diving in ocean sustainability, a thorough investigation revealed just how impactful this sector can be.

Beyond being a fun hobby, scuba diving contributes between $8.5 and $20.4 billion to the global economy annually, supporting up to 124,000 jobs across 170 countries. "Unlike mass tourism operations that can harm local communities and marine environments, dive tourism, when managed well, can be economically viable, socially equitable and environmentally sustainable," said Anna Schuhbauer, postdoctoral fellow at the Institute for the Oceans and Fisheries.

Divers consistently seek out marine protected areas— places where ocean life thrives under conservation safeguards. "With a vested interest in healthy ecosystems and abundant marine life, dive operators are natural allies in conservation efforts,” says Schuhbauer.

Healthy marine ecosystems not only attract tourists but also support local economies and strengthen incentives to protect biodiversity. As a result, literally taking a deep dive has the potential to contribute to transformative change in marine ecosystems.

Healthy as a horse

This idiom refers to being strong and well. And the Project Seahorse team at the Institute for the Oceans and Fisheries (IOF) is working to ensure just that, for our oceans. With seahorses at the heart of their mission, they conduct research and rally action that protects marine ecosystems that are so valuable for seahorses and countless other species.

Their recently published paper, led by IOF alum Tanvi Vaidyanathan, introduces a practical 5-Question Approach to guide countries toward more sustainable trade in wildlife. It helps decision-makers assess where wildlife is found, what pressures they face, what management is in place, if it’s being implemented, and how populations are responding.

This innovative 5-Question tool is already being deployed to guide national conservation action in the Philippines, Indonesia, and most recently in Sri Lanka. We see huge potential for its application across many species, from sharks to sea cucumbers.

“It’s deeply gratifying to see my research contributing to national conservation strategies around the world. It makes me hopeful that thoughtful, evidence-based inquiry can drive more effective and sustainable management of species and their habitats—one question at a time,” said Vaidyanathan.

In hot water

This idiom refers to being in trouble: a perfect description for the impacts of marine heatwaves on fish stocks.

Marine heatwaves (MHWs)—periods of extremely high ocean temperatures—have increased in frequency, intensity, and duration due to increases in anthropogenic greenhouse gas emissions since the early 20th century.

“High ocean temperatures can, in part, reduce the capacity of habitats to support fish stocks,” explains Dr. William Cheung, Professor and Director of the Institute for the Oceans and Fisheries. When these temperatures persist over extended periods, they can limit growth and reproduction, increase mortality, and ultimately lead to lower biomass and shifts in species geographic ranges. Sensitivity to MHWs varies between species and regions. “Some fish populations are already living near the upper limit of the temperatures they can tolerate, have a narrower temperature tolerance range or are particularly vulnerable to rapid temperature changes.”

MHWs are expected to become more frequent in the future, compounding the long-term effects of climate change. “Considering MHWs with long-term ocean warming are expected to double the magnitude of impacts of climate change on fish populations by 2050, it’s likely that previous assessments have underestimated the risks facing fish stocks under climate change,” explains Cheung. Without swift mitigation and adaptation measures, both fisheries and the people who rely on them could find themselves in hot water!

A drop in the ocean

This idiom describes something so small it seems insignificant, but that cannot be said for pollutants in the ocean, which can have far-reaching consequences for marine biodiversity.

Many pollutants entering marine environments do not break down easily and can persist for years or even decades. These so-called “forever chemicals” tend to be widely used in everyday products such as food packaging, non-stick cookware, firefighting foam, and clothing. “Many pollutants are harmful even at low concentrations,” explains Dr. Juan José Alava, Honorary Research Associate at the Institute for the Oceans and Fisheries and founder of the Ocean Pollution Research Unit.

Forever chemicals can accumulate in the marine food web, impacting top predators such as the endangered southern resident and threatened Bigg’s (transient) killer whales along the BC coast. These pollutants can even transfer from mothers to calves before birth. Bioaccumulation poses health risks not only to wildlife but also to Indigenous people who strongly rely on traditional seafood.

The problem is compounded by the myth that dilution — simply dispersing or dissolving pollutants— is enough to solve it. “Dilution is not the solution to pollution,” cautions Alava. While a pollutant might seem like just a drop in the ocean, its impacts can be anything but small. “There is a need for preventive pollution measures and proper treatment before pollutants reach our oceans,” says Alava.

Having a whale of a time

This idiom means to enjoy oneself—but not all killer whale populations will be having a whale of a time as they navigate seasonal changes across their range.

In British Columbia, two populations of resident killer whales feed on their favourite meal: Chinook salmon. While northern resident killer whales have been steadily increasing in numbers over the past few decades, southern residents have not.

Dr. Andrew Trites, Professor at the Institute for the Oceans and Fisheries, offers insight into why the populations are faring so differently. “Both populations have access to different Chinook runs in different places at different times of the year.” Unlike northern residents, who live in waters between southern British Columbia to southern Alaska, southern residents feed in waters as far south as California.

While southern residents were found to have greater access to Chinook in summer than their northern counterparts, their numbers remain low in comparison. Chinook have declined throughout the Pacific, which appears to be affecting southern residents more severely. “Any food shortages that might explain the low numbers of southern residents appears to be happening in winter and spring, when they are farther south of British Columbia,” says Trites. Understanding the threats that limit this population in each season across their range is essential to preventing their extinction.

Life comes in waves

This idiom refers to the up-and-down nature of life. In the context of coastal ecosystems, this ebb and flow isn’t just metaphorical — it’s literal.

“Life in the ocean is cyclical,” explains Dr. Anna McLaskey, Research Associate at the Institute for the Oceans and Fisheries. “Activities and populations vary over the course of a day, across seasons, and over years.” Strong changes in sunlight, temperature, and winds drive these seasonal waves of life in British Columbia’s waters.

Phytoplankton — the microscopic plants that form the base of the marine food web — “grow exponentially during the first extended period of calm, sunny days in spring,” says McLaskey. This spring bloom feeds a surge in zooplankton, whose growing populations graze down the initial wave of phytoplankton. But this isn’t the end of the cycle — instead, it “allows a more diverse community of smaller phytoplankton to take its place.”

As the seasons shift, so do the diets and feeding strategies of zooplankton. During the winter months, “life may slow down, but it doesn’t stop. Carnivores are active and many omnivores switch to other foods like nanoflagellates — tiny organisms that eat bacteria,” McLaskey explains. Seasonal ‘waves’ in phytoplankton and zooplankton communities ultimately determine the quantity and quality of food available to consumers at higher trophic levels, such as fish and marine mammals.

Smoke on the water

This idiom warns: trouble is brewing. As climate change alters wildfire regimes, that warning is extended to aquatic ecosystems.

Wildfires play an important role in moving materials from the land to freshwater and marine environments, supporting nutrient cycling and aquatic food webs. However, “as fire seasons become longer and more intense in British Columbia, we may see increasing and prolonged inputs of fire-derived materials to both freshwater and coastal ecosystems, with consequences for water quality, carbon cycling, and marine food webs,” explains Emily Brown, who undertook this work as a part of her MSc at the Institute for the Oceans and Fisheries (IOF).

In the Fraser River Basin, up to 16.3% of changes in water quality could be linked to wildfire activity. “This demonstrates that fire plays such a significant role in water quality in this region and should encourage managers to monitor water quality more closely after wildfires,” said Brian Hunt, Associate Professor at the IOF. Understanding how wildfires affect aquatic systems is crucial to protecting them from even more ‘smoke on the water’ under future climate change.

Taking a nosedive

This idiom is often used to describe something suddenly descending—like a malfunctioning airplane. But for pinnipeds such as seals and sea lions, a nosedive is just another day in the ocean.

Pinnipeds are uniquely adapted to dive and stay underwater on a single breath for extended periods. As part of her PhD research at the Institute for the Oceans and Fisheries and UBC Department of Zoology, Dr. Rhea Storlund studied what makes this possible.

“Routine dive behaviour in pinnipeds is tied to their anatomy,” she explained. Contrary to the idiom’s suggestion, the key structure isn’t the nose—it’s the aortic bulb, a portion of the heart that is relatively enlarged in pinnipeds. “Individuals with larger aortic bulbs can spend more time foraging during typical dives.”

As climate change alters marine communities and human disturbances like vessel traffic increase, pinnipeds may be required to dive for longer durations. Despite their remarkable adaptations, “animals with smaller aortic bulbs may be less able to adjust their diving to reach deeper or more dispersed prey, potentially making them more vulnerable to environmental change,” Storlund 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.”

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.