By Grace Klinger, Science Communications Fellow at Shedd Aquarium
Worldwide, the seafood industry represents $362 billion in first sale value for the global economy and accounts for roughly 59.6 million jobs. Given its economic value, it is important to keep a close eye on the way the seafood industry is managed to ensure it is viable long-term. National Seafood Month, celebrated in the month of October, raises awareness about why it’s important to support sustainable and responsible fisheries (fishing industries) and how consumers can help by choosing to eat sustainable seafood.
Sustainable seafood is seafood that is harvested in ways that allow people to enjoy seafood for years to come without leaving the fish populations unrecoverable. It allows the fishing industry to flourish while keeping the aquatic habitats, which support the fishing industry, healthy. Without sustainable fishing practices, we put the delicate balance of the food webs in the world’s oceans and lakes at risk.
Global decreases in marine fish populations have a negative impact on the fishing industry. There is an estimated 31 percent of marine species that are overfished, according to a report from the Food and Agriculture Organization of the United Nations, suggesting that more sustainable management of fisheries is needed across the globe.
One example of unsustainable fishing practices that Shedd Aquarium’s marine research team studies involves catching fish during spawning, or mating, and as fish migrate to spawning sites. Harvest during these critical windows removes large numbers of fish before they can reproduce and puts the next generation at risk. The short-term gains of fishing during these times produce massive catches and financial benefits for fishers. However, long term effects include fewer fish and jobs in subsequent years for the fishing industry and – ecologically – an increase in marine animals approaching the Endangered Species List.
For example, Caribbean snapper species are important reef fishes and a valuable seafood source. Five known snapper species have at least 20 spawning aggregation sites surrounding Cuba where many thousands of fish gather to mate. Long migration routes between far-flung spawning sites create challenges to prevent snapper overfishing. One conservation management strategy involves setting up marine protected areas near the aggregation sites and along migration routes, where no fishing is allowed, although illegal fishing and large management areas make this difficult to enforce.
Our Shedd research team partnered with researchers at the Florida Institute of Technology, University of Miami and the Institute of Marine Sciences in Havana, Cuba to try to address snapper conservation. The researchers collected data to help guide management of vulnerable snapper during their migrations and spawning times by tracking spawning events and modeling the dispersal of larvae, or baby fish, after spawning.
Why track snapper larvae too?
To ensure a “stock,” or species, is fished sustainably, it is important to know where the next generation is coming from. Understanding how fish populations are connected lets us pinpoint which areas need protection based on larvae export, or dispersal, which helps replenish populations. We can also learn if the aggregation site is “self-recruited,” meaning that the larvae are not from distant areas, but rather that they come from the local stock.
Tracking spawning events is relatively predictable because they follow the cycles of the moon. Larvae dispersal, however, is much more difficult to monitor or model. This is because of the underwater current, hurricane movements and even underwater terrain that can force larvae to stay in the same area or be transported long distances.
What Shedd’s research team found, published this year in Fisheries Oceanography, is that Cuban snapper larvae dispersal can widely vary depending on different sites around the island. While some sites exhibit high self-recruitment, other sites show far dispersal routes to other countries near Cuba, which help replenish those nations’ snapper populations. This means that there can be a high larvae export at many spawning sites, all the while larvae are being “imported” from other aggregation sites.
These high export/import sites suggest the need for aggregation protection. However, current local protection varies. To fulfill the inadequacies of the marine protected areas on the spawning and pre-spawning aggregation sites, the study suggested implementing seasonal no-fishing bans for these spawning marine fishes to ensure this fishery operates sustainably.
The Caribbean snapper is an example of how science can help ensure that seafood is sustainable by identifying problems and proposing solutions before a fish population disappears. Indeed, many fishery stocks have been rebuilt in recent years due, in part, to sustainable management practices and increased awareness of the problem of overfishing. That is why celebrations like National Seafood Month are so important – being part of the solution means being an informed consumer.
Monterey Bay Aquarium’s Seafood Watch app helps you stay up-to-date on fish stocks and “best choice” seafood options. Additionally, you can support sustainable fisheries by simply choosing seafood off the beaten path. Diversify your diet and try different types of seafood to decrease demand on shrimp, tuna and salmon, which make up more than 50 percent of seafood consumed in the U.S.
For more information about how you can be an educated seafood consumer, visit www.sheddaquarium.org/seafood.