Jellyfish 
All coastal upwelling systems globally are subject to strong anthropogenic pressures, such as intense fishing, pollution, and climate change, which are furthering the increase of massive jellyfish blooms. Overfishing and unintended capture of species that feed on jellyfish, such as small pelagic fishes and sea turtles, has led to the “jellyfication” of some ecosystems. One of the most important pieces of evidence of “jellyfication” comes from the Benguela upwelling ecosystem in Namibia where the decades-long overfishing of commercially important pelagic fish, who compete with jellyfish for food and also feed on jellyfish eggs and larvae, led to spectacular and sustained changes that have affected all trophic levels. 

No longer having their small pelagic fish competitors, jellyfish thrived and dominated in this ecosystem producing a collapse of fishing yields. On the other hand, increasing plastic and glass pollution in the ocean offers jellyfish increased substrates where their larvae can attach, an important part of the life cycle of jellyfish. These artificial substrates provided by plastic, glass, and even concrete in the ocean appear to be preferred by jellyfish larvae more than the natural ones (pebbles, rocks, or shells). Ultimately, the increase of anthropogenic substrates for attachment leads to a rapid population growth, in massive numbers, of jellyfish. Add to these the increasing temperatures due to climate change, and we may see further expansion of jellyfish populations. But some people are already brainstorming how to make jellyfish useful. Check GoJelly to learn more about their ‘gelatinous solution to plastic pollution’. 

Small-scale fisheries
For those of us who love seafood, it is important to know how our seafood was captured, because we may be inadvertently impacting other species, many of them at risk of extinction. Fisheries’ bycatch, the unintended capture of marine animals, is the largest threat to sea turtles, seabirds, dolphins, and other marine animals as they get injured or die as a result of their interactions with fishing gear. But fisheries provide food and employment for millions of people worldwide, especially small-scale fisheries (small fishing vessels that rely on manual work), which are responsible for landing nearly half of the world’s seafood and employ more people than other fisheries. In fact, more than 90% of fishers worldwide participate in small-scale fisheries! 

Fortunately, researchers have developed and tested tools to reduce capturing endangered and protected animals such as sea turtles and dolphins. Implementing these bycatch mitigation tools will ensure the sustainability of fisheries, where fishers continue to support the communities that rely on them while also protecting marine animals. Read this article to learn more about how a Peruvian NGO is working with small-scale fisheries to save the critically endangered Eastern Pacific Leatherback population, featured in this TED Ed video. And we can also do our part by making sure we are eating sustainably captured seafood (harvested in ways that don’t harm other wildlife) by checking the labels of packages and learning what seafood is in season. The Monterey Bay Aquarium Seafood Watch is a great source for looking up the sustainability of various seafood.

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