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The Skimmer on Marine Ecosystems and Management

Editor’s note: In 2016, roughly one-third of the total value of the world’s trade of fish and fish products was invertebrates. (They were approximately one-fifth of the global fish trade by live weight.) To learn more about the state and future of invertebrate fisheries management, The Skimmer interviewed Heike Lotze, a professor in the Department of Biology at Dalhousie University in Halifax, Canada. In this interview, we discuss several of her papers published over the past decade on the recent expansion, ecosystem effects, and management of invertebrate fisheries, including a recent synthesis “Ecosystem effects of invertebrate fisheries” published in Fish and Fisheries in 2017.

The Skimmer: As global catch of invertebrates increases, what impacts are invertebrate fisheries having on marine ecosystems?

Lotze: Invertebrate catches have increased more than six-fold globally since the 1950s. Catches include all major species groups – from lobster, shrimp, and crabs (crustaceans) to octopus, cuttlefish and squid (cephalopods) to mussels and snails (mollusks) to sea urchins and sea cucumbers (echinoderms). In many countries, invertebrates are some of the most lucrative commercial fisheries and provide coastal communities with valuable livelihoods and associated benefits. The global increase in catches has been accompanied by the spatial expansion of invertebrate fisheries: many more countries are engaging in fishing invertebrates, and many more areas within countries are now fishing invertebrates. For example, sea urchin and sea cucumber are now fished around the globe, and fishing for invertebrates has expanded from shallow to deeper waters to maintain or enhance catch levels. Fisheries have further shifted from large- to smaller-sized individuals and from high- to lesser-valued species, usually in response to declining catches and following a ‘fishing down the value-chain’ pattern.

Many people may think it is ‘just’ invertebrates, but these species play important ecological roles in marine ecosystems. These roles are often more diverse than the roles that fish play, consequently the impacts of invertebrate fisheries on other species and marine ecosystems are more varied than those of finfish fisheries. For example:

  • Many invertebrates are important prey for higher trophic level species, such as fish, whales, turtles, and seabirds, and reducing invertebrate abundance can have ripple effects through marine food webs, comparable to those of forage fish;
  • Many mussels, oysters, and sponges enhance biodiversity by creating three-dimensional structures that are important habitat for other species – for settlement, finding food, finding shelter, breeding, and nursery grounds;
  • Many invertebrates filter feed which improves water quality and clarity and provides benefits to other organisms, including humans;
  • Herbivore grazers, such as many urchins and gastropods, act as lawn mowers keeping algal carpets in check; and
  • Detritivore sea stars and sea cucumbers clean up ocean floors as the scavengers of the sea.
The Skimmer on Marine Ecosystems and Management

Editor’s Note: From the Archives calls attention to past Skimmer/MEAM articles whose perspectives and insight remain relevant.

Coverage of social media usually focuses on how social media platforms (e.g., Twitter, Facebook) can be used to communicate with and educate stakeholders and the general public. But social media also provides publicly available information on how people are using and feeling about the marine environment. Learn how social media and other digital data are being used for marine conservation and management.

The Skimmer on Marine Ecosystems and Management

Editor’s note: We’ve all read about how ocean noise can harm marine mammals. New research reveals that it can have profound impacts on lower trophic levels as well, with likely consequences for marine ecosystems. Catch up on the latest research with this month’s Skimmer.

A little background on sound in the ocean

The Skimmer on Marine Ecosystems and Management

Editor’s note: Heather Welch is a research associate with the University of California at Santa Cruz and the (US) NOAA Southwest Fisheries Science Center’s Environmental Research Division. The Skimmer spoke with her about her research, which focuses on understanding and planning for the spatial and temporal dynamics of large-scale marine processes.
 

The Skimmer: We last covered dynamic ocean management and dynamic ocean management tools in 2014. Can you tell us a bit about how the field has progressed since then?

One area of progress is that dynamic ocean management is now better located within the larger field of dynamic management, allowing us to borrow concepts and methodologies from more established disciplines. Weather science has been developing dynamic management tools such as weather forecasts and hurricane forecast tracks for over a century. While on land, established dynamic management tools track floods, wildfires, and disease outbreaks. Understanding the parallels between dynamic ocean management and dynamic management in other realms allows us to leverage lessons learned and avoid reinventing the wheel.

Another area of advancement is that dynamic ocean management tools are moving towards producing forecasts. Initially, tools were producing hindcasts and nowcasts, i.e., predicting where species were last month and where species are today, respectively. Now, dynamic ocean management tools are forecasting species distributions days to seasons in advance. For example, the Atlantic Sturgeon Risk Model predicts Atlantic sturgeon habitat one to three days in advance to help fishers avoid the bycatch of these endangered fish. A seasonal forecasting system in the Great Australia Bight predicts the distribution of Southern bluefin tuna several months into the future to help fishers efficiently locate and harvest their target species. These types of forecasts give end-users time to plan ahead for future conditions.

Lastly, dynamic ocean management is moving from single-species tools to multi-species tools that can address greater proportions of biodiversity. Single-species management was a natural starting point for the field, but established methodologies and technological advances now allow for more complex tools. For example, TurtleWatch helps fishers avoid the bycatch of loggerhead and leatherback turtles. On the US west coast, EcoCast helps fishers maintain their target catch of swordfish while avoiding the bycatch of loggerhead turtles, California sea lions, and blue sharks.
 

The Skimmer on Marine Ecosystems and Management

In case you missed it, last month’s issue of The Skimmer featured original articles:

The Skimmer on Marine Ecosystems and Management

In recent years, stakeholder engagement has been widely recognized as integral to effective marine conservation, marine ecosystem-based management, and marine spatial planning. There are many different definitions of the term ”stakeholder”, but at its most inclusive, it is any “person, organization, or group with an interest (professional or societal) or an influence on the marine environment or who is influenced directly or indirectly by activities and management decisions.” The list of stakeholders engaged in any marine conservation or management process depends on the context of the specific project, but, in practice, typical stakeholders engaged in marine conservation and management processes include local industries, coastal residents, management agencies, and conservation organizations.

The world is changing rapidly though. New information and technologies, new forms of social interaction (often fostered by social media), increases in tourism around the globe, shifting economies, globalization, global climate change, and other factors make it critical to continually reexamine traditional views of who ocean stakeholders are, their relative importance, and how we engage them.

In this issue of The Skimmer, we feature three recent studies that highlight new (or often underrepresented) voices in ocean management processes, as well as thoughts on how these voices can be brought into decision making for marine ecosystems.

The Skimmer on Marine Ecosystems and Management

Editor’s note: The Slimmer Skimmer is a new feature to give a brief update on a topic critical to marine ecosystem management.

We are starting off our Slimmer Skimmer series with one of fisheries subsidies. The World Trade Organization is currently working to make an end-of-the year deadline (their own, as well as one for the Sustainable Development Goals) to end harmful types of fisheries subsidies. Not all fisheries subsidies are harmful – fisheries management is commonly considered a subsidy, for instance – but the harmful ones encourage overfishing and have substantial negative impacts on marine ecosystems.

Please let us know what you think of this type of feature and if there is anything that you feel we should cover in this format in the future.

So let’s start with a few basics – what are fisheries subsidies?

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