Coral Reef Research Foundation | Reef Fisheries
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Reef Fisheries

At CRRF we are involved in fishery data collection to help address knowledge gaps that can preclude effective management of reef fisheries.

Much of the fish that supplies local markets and personal consumption in Palau is caught from the near-shore barrier reef and lagoon. However it is widely regarded form long-term fishermen that the abundance and size of reef fish have decreased in the last two decades. Fortunately there has been renewed interest in fisheries management to stem the decline.

To best guide management decisions, we need to understand the status of the stock along with biological information to determine the growth and maturity of the many species caught. To assess the stocks with limited information, data-poor stock assessment techniques have been developed to help bridge the gap between the expensive data-rich assessments conducted only for the most valuable fisheries in the world, and the vast majority of smaller fisheries, especially those on coral reefs that support millions of fishers. Data-poor stock assessment methods in its simplest form require information on the size structure of the population along with an estimate of local size at maturity and or asymptotic length.

At CRRF we are involved in fishery data collection to help address knowledge gaps that can preclude effective management of reef fisheries. We employ novel technology to improve the efficiency of data collection and can provide accurate species identifications for the hundreds of species caught on coral reefs in the Pacific. We are currently working on determining the size at maturity of important commercial species and using new methods to answer these questions efficiently.

Dr. Steven Lindfield is the lead on reef fisheries projects, coming from a commercial fishing family in Australia; he has been studying coral reef fish and fisheries in Micronesia since 2010.

Current projects

Size at maturity of eight fishery targeted species.

Although size at maturity (Lm) is a necessary parameter for assessing the sustainability of a fish stock and implementing management such as size limits, the Lm of most coral reef species has not been determined. Furthermore, the maximum size and size at maturity of a given species varies between geographic areas, making it essential to measure this parameter at the national level. We are currently working to generate accurate measures of Lm for eight fishery-targeted species, adding to available preliminary data for 12 commonly fished species in Palau (see Prince et al. 2015). To do this, we dissect fish across a range of sizes and collect their gonads for histological inspection. We also collect fish ear-bones (otoliths) and tissue samples for genetic analysis.

Species we are working on: Caranx melampygus, Aprion virescens, Monotaxis grandoculis, Plectorhincus lineatus, Epinphelus polyphekadion, Lutjanus bohar, Hipposcarus longiceps, Lethrinus olivaceus.

Palau’s reef fisheries: changes in size and spawning potential from past to present.

This project first analyzed stereo-video footage collected by Steve Lindfield and the Bureau of Marine Resources at the main reef fish market in Palau. These data collected over a 3-month period resulted in length measurements of 2675 fish from 86 different species. These size frequencies were then compared to data collected in the 1980-90s for the main eight species in the catch. A new data-poor stock assessment technique, the length-based assessment of spawning potential ratio (LB-SPR) was then applied to these species and we found the majority of fishery-targeted species in Palau are currently at a low level of reproductive potential or are quickly approaching a level where potential for stock replenishment is impaired. These data will provide a good baseline to track the hopeful recovery of reef fish stocks into the future with increased fisheries management and awareness of the previous declines.