The demand for trendy sushi restaurant menu items, coupled with steadily rising seafood consumption in general, has become a threat to marine ecosystem conservation efforts. To accommodate the growing demand for fish, many endangered fish species are labelled under generic, misleading names so that they can be sold in the market. Moreover, overfishing decreases the ocean’s ability to withstand the various impacts of climate change.

The Varsity set out to investigate overexploitation by the fishing industry in marine ecosystems.

Overfishing has gone global

Ecosystem overfishing (EOF) is described as an unsustainable fishing practice which threatens not only specific fish populations, but the larger marine ecosystems as well. A recent study highlighted how being overly focused on target populations without considering the larger ecosystem is a problematic approach to fishery management.

The researchers who did the study described a way to effectively detect ecosystem overfishing based on widely available satellite data. They constructed measurement indices based on the ratios between the populations of fish and the percentage of those populations being fished. For high-income nations, these indices are much more efficient than piecing together data on fish species, population by population. Since the monitoring and enforcement of fisheries is lacking in many low-income nations, easy indicators of EOF are both pragmatic and valuable.

According to the results of the study, “the occurrence of EOF in [large marine ecosystems] is consistently detected across all indicators.”

Tropical regions have been the marine ecosystems worst affected by EOF, which makes them particularly vulnerable to the implications of climate change. Rising ocean temperatures prompt fish populations to migrate to higher latitudes. Without shifting associated fisheries to accommodate the migration trends, more pressure is exerted on the tropical marine ecosystems. Based on these observations, it seems likely that a global abundance of EOF is happening right now.

The ocean’s health crisis

The United Nations’ Food and Agriculture Organization (FAO) pointed out that one-third of fish stock worldwide is experiencing depletion due to “overfishing and habitat destruction.” Marine organisms are already impacted by climate-induced changes in the ocean. With all the additional stress from overfishing, the ocean is undergoing a health crisis, which includes a loss of biodiversity.

Overfishing has already done damage to ecosystems by restructuring their food chains. Essentially, fish species at the top of food chains are being disproportionately fished out of the ecosystem. The absence of these valuable species leads to gradual effects trickling down the marine food chain. Such unsustainable fishing practices result in a serial depletion of marine ecosystems, which is also known as “trophic cascade.”

Having healthy fish stock is critical to the overall functioning of ocean ecosystems, as well as certain planetary functions. For instance, the ocean is known to play an indispensable role in regulating carbon in the atmosphere. Therefore, revitalizing the ocean’s biodiversity by ending overfishing will also strengthen the ocean’s overall health and the Earth’s response to climate change.

The Canadian tragedy of the Atlantic cod

The problem of overfishing is also deeply rooted in Canada’s past and present, as can be seen in the collapse of the Atlantic cod fishery. For almost 500 years, the Newfoundland North Atlantic cod stock was deemed one of the largest sources of fish in the world. 

However, after two billion individual cod were lost to years of unregulated fishing, only one per cent of the historical population was left. The Canadian government issued the 1992 Cod Moratorium subsequent to the collapse of the cod population in order to put an end to cod fishing in the hopes of preserving the population.

Almost 30 years after the 1992 Cod Moratorium, the question of whether the Newfoundland cod population will recover still remains unanswered. Scientists are concerned about the possibility that the Newfoundland cod population will never recover under the current management of the federal Fishery Department.

The federal government’s cod population rebuilding plans, released last December, prompted both scientists and fish harvesters to call on Ottawa for revisions. According to a CBC report, the long-anticipated plan “ignores the latest science [and] sets no timelines,” which puts the future of Newfoundland fishery in jeopardy.

Back to the sushi menu

US researchers have revealed the prevalence of mislabelled seafood in places like grocery stores, fish markets, and even sushi restaurants.

In a sample used in the case study, seven species of rockfish were sold under the generic name of “Pacific red snapper” on the menus of sushi restaurants across California and Washington. Shockingly, the researchers found that 56 per cent of the rockfish samples they identified were “species listed as overfished by the [US] National Marine Fisheries Service.” In a separate trial, using DNA forensics, they were also able to identify 11 different species from three taxonomic families of fish in 77 fish fillet samples labeled “Pacific red snapper.” When food providers can  sell all rockfish under one common label, it impedes consumers from making informed choices.

The ambiguity that leads to food providers mislabelling fish species arises in the process of mixed-species fisheries selling all their products under one generic name. For example, the generic label ‘salmon’ includes multiple endangered species. This phenomenon is commonly seen in seafood markets, and these mislabelled fish end up listed under ambiguous menu item descriptions in sushi restaurants.

Seafood retailers commonly relabel less expensive species of fish to appear to be more expensive or of higher quality. Such misnaming and substitution is illegal if the seafood is transported across states or the US international border. The challenge is that laws about labelling seafood are not under US federal jurisdiction. Although the US and Canada have placed numerous restrictions and regulations on rockfish fisheries, there is a period from the time of catch to the final point of sale when fish are not consistently identified, which makes them hard to regulate.

No matter how educated consumers are on the subject of sustainable seafood consumption, once information about the fish they’re consuming reaches the marketplace, it’s inaccurate — so consumers are not able to make informed decisions.  Hence, pushing governmental action to eliminate misleading vernacular names in seafood markets is a significant step toward preventing the depletion of fish stock. Meanwhile, consumers rely on organizations such as the World Wildlife Fund to collaborate with seafood retailers and offer environmentally sound choices that sustain ocean health in the long term.