Where reefs are restaurants, challenge is keeping them stocked

Coral and reef fish on scuba diving excursion to Black Rock. (© Conservation International/photo by Edgardo Ochoa)

Hawaii’s coral reefs are more than just a picturesque tourist destination — for local communities, they’re a critical source of food.

The challenge? Ensuring that they continue to remain so.

In a scientific paper published earlier this week in the open-access journal PeerJ, scientists David Delaney of the University of Hawai‘i at Mānoa and Jack Kittinger of Conservation International (CI) made the case for getting communities themselves involved in protecting these fisheries.

Doing so requires sufficient information on how much is being caught and where — information that few local anglers are willing to give up so easily. But by compiling catch data, the scientists were able to develop the clearest picture of shore-based fishing in Hawai‘i yet obtained — revealing fishing patterns in a place where fishing is a way of life.

In the interview below, Delaney and Kittinger to discuss their findings.

Question: Where are local people fishing in the Hawaiian Islands and how?

David Delaney (DD): In terms of where people are fishing, the highest estimates were on O‘ahu, which is the most populated island in the archipelago. Drilling down even further, Pearl Harbor, a densely populated bay in urban Honolulu, had the highest estimate, with just over 100,000 hours of non-vessel-based fishing, nearly all of which was line fishing. The amount of fishing was generally lower on less populated areas of the main Hawaiian Islands.

Q: Your research was based on conducting “creel surveys.” What does this mean, and why is it important?

DD: The name creel survey comes from the woven basket, or creel, that some freshwater anglers use to hold their catch. A creel survey is a study to quantify how much fishing is happening, what fishing gears are being used, how much is being caught, what species are caught, and how effective fishers are at catching the fish.

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Jack Kittinger (JK): Have you ever asked a fisher where they landed their catch? Good luck getting that information out of them! Fishers are often understandably protective about their favorite spots, gear and methods. The creel survey is an opportunity to finally glean this information.

 For this study, we looked at a range of these surveys — 18 in total — that have been done by, or directly with, communities in Hawai‘i. These local surveying efforts largely meant the community was surveying themselves. These surveys required some 10,000 hours to complete — they’re a treasure trove of data and information on coral reef fisheries. Dave was then able to bring all that complex information together so we can start to understand patterns in catch, effort and more effective options for management to keep fisheries healthy and to support the livelihoods of fishers.

 Q: Did anything in your findings surprise you?

JK: One major finding that sticks out is just how much of these fishers’ catch is going into local households. Very little of this catch is being sold — it is primarily kept for home consumption or given away, an important practice of sharing that has cultural origins and is part of maintaining social kinship ties at the community level. We are starting to realize that if these fisheries continue to decline, it will have a real impact on food security.

Critically, this study, together with our previous work on the value of coral reef fisheries, is making the benefits of these reef fisheries more visible. We know now that these reef fisheries provide more than 7 million meals per year, that most of the catch from these fisheries goes directly into local households, supporting food security and that the overall value of these fisheries is [between] US$ 10 million and US$ 16 million.

Q: You reported a high occurrence of illegal fishing at some locations. What can be done to address this?

DD: To put it simply, local monitoring is an effective tool for reducing illegal fishing. To best monitor illegal fishing, we need to get communities engaged, and these creel surveys have been an effective way to get people to put “eyes on the reef.” Because fishing is generally higher on weekends and holidays during non-winter months, monitoring those times and locations could lead to a better understanding of fishing activities and better enforcement of current regulations.

Fish provide food security and recreational fisheries provide cultural value for the people of Hawai‘i, particularly in rural areas. Ultimately, individuals, communities, non-profits, businesses, state and federal government all have to collaborate to protect and restore our reefs and the fisheries benefits that we rely on.

Q: What needs to be done to help make Hawaii’s reef fisheries sustainable?

JK: The gold standard in fisheries management — indeed on of the most fundamental pieces of information that we need to make good management decisions — is called “catch per unit effort.” What is this? If it takes me an hour to catch enough food to feed my family in geography A, and twice as much time in geography B (assuming all things are equal), then in general it’s a pretty fair assumption that the fishery in geography B has less fish and is in a poorer state.

Taking it a step further, by assessing the catch per unit effort for different types of fishing gear (net and spear vs. line, for example), we can start to look at options like gear-based management for restoring or sustaining fisheries. Paired with better information on the status of the fish stock in a given location, this then opens up a powerful space where we can start to develop effective controls on effort (who can fish, when and where) and on catch (how much can we fish without outstripping the ability of fisheries to replenish themselves).

These are called input and output controls, respectively, and for them to work we absolutely have to pair these different interventions with effective enforcement (so “free riders” don’t game the system to everyone’s detriment), and strong monitoring and assessment (so we can know what is and isn’t working, and why). In coral reefs where these rules are in place, they are generally healthier and better able to support local families.

David Delaney is a scientist at the University of Hawai‘i at Mānoa. Jack Kittinger is senior director of CI’s Global Aquaculture and Fisheries program. Eva Schemmel is the science adviser for CI Hawai‘i .

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