Nav: Home

Understanding how fishers fish on coral reefs can inform fishery management strategies

July 31, 2017

A Dartmouth study of spearfishing on a Caribbean coral reef illustrates how understanding the process of fishing can help in developing management strategies to address overfishing and coral reef protection worldwide. Understanding which fish are targeted, when, why and where in a coral reef habitat, are important details that extend beyond catch limits or even bans that so often define fishing regulations. The findings are published in PLOS ONE.

This study examines spearfishing in a rural village in northwest Dominican Republic, where this type of artisanal fishing serves as the main source of livelihood for residents in this community and throughout the Caribbean. In coral reefs and seagrass beds, finfish such as parrotfish, grouper and grunt, and invertebrates such as lobster, conch and crab, are among the species that are highly sought after, for their market value in addition to fulfilling subsistence needs.

Parrotfish are a staple in Dominicans' diet but they also play a vital role in the health of coral reefs, as these herbivores eat macroalgae or large algae that compete with coral, and help prevent algae from overgrowing, which could smother coral and take over reefs.

Spearfishing may be one of the most selective fishing methods, as fishers have up until the last possible second to determine which fish to target. Using cameras mounted onto spearguns, researchers investigated the differences between fishers who free dove (in waters less than 10 meters deep), and those who dove with compressed air (in waters between 10 and 35 meters deep), to see how the different equipment affects which fish are targeted. By analyzing video footage, the different types of fish observed and caught were catalogued, and classified by market value, along with other data documenting fishers' decision-making.

Compressor divers encountered more higher quality fish, caught each fish more efficiently, and caught 69 percent of the fish that they targeted or 28 percent more than freedivers. It is likely that compressor divers encountered more fish given that they had access to deeper reefs.

Parrotfish were targeted the most. Even though they did not fall into the highest market value category, parrotfish accounted for nearly half of the encounters in which no other types of fish were present, or 40 percent of such opportunities for compressor divers and 50 percent for freedivers.

"Spearfishing underlies the economic and social organization of this community, but also degrades fishery resources when left unmanaged," says lead author Tyler Pavlowich, a Ph.D. candidate in the ecology, evolution, ecosystems and society graduate program at Dartmouth.

In considering management strategies to protect parrotfish populations from overfishing on coral reefs, the data illustrate how an outright ban on parrotfish could severely eliminate opportunities for fishers. Prohibiting compressor diving, another option being considered, would also inherently limit fishers' opportunities and restrict how many fish they can catch. This study helps inform the difficult decisions of how to restrict fishing to safeguard ecosystems without imparting undue hardship for fishers.

To help ensure the health of marine ecosystems, last month, the Dominican Republic government issued a two year ban on the capture and commercialization of parrotfish, as well as prohibitions on catching long spine urchin (another important herbivore on reefs) and all sharks and rays. Whether the ban can be effectively enforced remains to be seen, as a lack of resources often makes enforcement)measures challenging.

The study is part of Pavlowich's dissertation, which also explores possible fishery management strategies that take into account the life-history of stoplight parrotfish, an ecologically- and economically-important parrotfish species, as well as other options for fishing restrictions in the area. It is an ongoing collaboration with members of the Buen Hombre community and with AgroFrontera, a non-governmental organization in the Dominican Republic, which is working to address sustainable agriculture and sustainable fisheries in the country.

Lead author Tyler Pavlowich is available for comment at: Anne Kapuscinski, professor of environmental studies and the Sherman Fairchild Distinguished Professor in Sustainability Science, served as the study's co-author.
Broadcast studios: Dartmouth has TV and radio studios available for interviews. For more information, visit:

Dartmouth College

Related Coral Reefs Articles:

3-D printed coral could help endangered reefs
Threats to coral reefs are everywhere--rising water temperatures, ocean acidification, coral bleaching, fishing and other human activities.
Actions to save coral reefs could benefit all ecosystems
Scientists say bolder actions to protect the world's coral reefs will benefit all ecosystems, human livelihoods and improve food security.
Coral reefs shifting away from equator
Coral reefs are retreating from equatorial waters and establishing new reefs in more temperate regions, according to new research in the journal Marine Ecology Progress Series.
Protecting coral reefs in a deteriorating environment
A new report examines novel approaches for saving coral reefs imperiled by climate change, and how local decision-makers can assess the risks and benefits of intervention.
Coral reefs can't return from acid trip
When put to the test, corals and coralline algae are not able to acclimatise to ocean acidification.
New eDNA technology used to quickly assess coral reefs
Scientists at the University of Hawai`i at Mānoa Department of Biology have developed a technique for measuring the amount of living coral on a reef by analyzing DNA in small samples of seawater.
Global warming disrupts recovery of coral reefs
The damage caused to the Great Barrier Reef by global warming has compromised the capacity of its corals to recover, according to new research published today in Nature.
Coral reefs near equator less affected by ocean warming
Ocean warming is threatening coral reefs globally, with persistent thermal stress events degrading coral reefs worldwide, but a new study has found that corals at or near the equator are affected less than corals elsewhere.
How sponges undermine coral reefs from within
Coral reefs are demolished from within, by bio-eroding sponges. Seeking refuge from predators, these sponges bore tunnels into the carbonate coral structures, thus weakening the reefs.
A glimmer of hope for the world's coral reefs
The future of the world's coral reefs is uncertain, as the impact of global heating continues to escalate.
More Coral Reefs News and Coral Reefs Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.