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Author ORCID Identifier

https://orcid.org/0000-0002-5183-1969

AccessType

Campus-Only Access for Five (5) Years

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Environmental Conservation

Year Degree Awarded

2019

Month Degree Awarded

September

First Advisor

Andy Danylchuk

Subject Categories

Aquaculture and Fisheries

Abstract

Artisanal coral reef fisheries are vital to food security and economic opportunity in coastal communities throughout the developing world. However, these fisheries are becoming increasingly threatened by over exploitation, and a basic understanding of the species harvested, and their life history is required to promote effective fisheries management. Such is the case on Anaa Atoll in the Tuamotu Archipelago of French Polynesia where the community depends on the harvest of coral reef fisheries. The purpose of this dissertation was to provide an assessment of the atoll’s fisheries, with an emphasis on bonefish; the community’s most valued fisheries resource. To do so, I utilized a combination of fisheries techniques including a creel survey to broadly describe artisanal fishing in Anaa Atoll; life history studies to describe their age, growth, reproductive characteristics and mortality; conventional mark and recapture to obtain a basic understanding of their movements and population size; acoustic telemetry to describe the spatiotemporal characteristics of bonefish spawning migrations and their overlap with the artisanal trap fishery; and applying data limited length-based fisheries methodologies to deliver an assessment of the populations spawning stock. My results indicate that Bonefish (Albula glossodonta) comprised 25% of the overall catch in the artisanal fishery and reached a maximum age that is below the 20-year longevity of the genus (8 years in males and 10 years in females). Differential growth patterns existed between the two sexes (L∞= 58, 78 cm FL andK = 0.38, 0.21 for males and females, respectively). Males attained sexual maturity at 43 cm FL (~3 years) whereas females matured at 48 cm FL (~4 years). Over the course of the study, I tagged and released 2,509 bonefish and 12.27 % were recaptured over a period of 3 years, 94% of which were recaptured by artisanal fish traps located in the migratory corridors of the atoll. Acoustic telemetry revealed that the spawning movements of bonefish into these corridors coincided with the waning gibbous moon during the austral winter and fall and were restricted to the northern section of the atoll, with 99.6% of all detections at offshore spawning habitats occurring adjacent to the atoll’s artisanal fish trap complex. An assessment of the bonefish spawning stock across a three-year period (2016 to 2018) indicates that the annual Spawning Potential Ratio (SPR) of the population was between 7-11% for each of the sampling years, well below the biological reference point F40%. The extreme right-tail values of every fisheries indicator and biological reference point suggests that the fishery was overexploited and in urgent need of management. To this aim, I used a hybrid system of outreach and youth education, to build social cohesion and support the renaissance of traditional management of this fisheries resource. In response, the community of Anaa Atoll 1) established an Educational Managed Marine Area (EMMA), which overlaps with the bonefish migratory corridor adjacent to Tukuhora village where the population is heavily exploited and 2) instated a temporal Rāhui inside the EMMA during the peak months of the spawning season. Considering these positive management outcomes, the results provide an important reference point from which the recovery of this population can be monitored in future years.

DOI

https://doi.org/10.7275/15162622

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