Assessing Assemblage Composition of Reproductively Mature Resource Fishes at a Community Based Subsistence Fishing Area (CBSFA)

Rebecca M Weible,Cynthia L Hunter,Alan M Friedlander,Ku‘Ulei S Rodgers

doi:10.3390/d13030114

Rebecca M Weible, Cynthia L Hunter + Show 2 more

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https://doi.org/10.3390/d13030114

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Abstract

Nearshore fisheries in Hawai‘i have been steadily decreasing for over a century. Marine protected areas (MPAs) have been utilized as a method to both conserve biodiversity and enhance fisheries. The composition of resource fishes within and directly outside of the recently established Hā‘ena Community Based Subsistence Fishing Area (CBSFA) on the island of Kaua‘i were assessed to determine temporal and spatial patterns in assemblage structure. In situ visual surveys of fishes, invertebrates, and benthos were conducted using a stratified random sampling design to evaluate the efficacy of the MPA between 2016 and 2020. L50 values—defined as the size at which half of the individuals in a population have reached reproductive maturity—were used as proxies for identifying reproductively mature resource fishes both inside and outside the CBSFA. Surveys between 2016 and 2020 did not indicate strong temporal or spatial changes in overall resource fish assemblage structure; however, some species-specific changes were evident. Although overall resource species diversity and richness were significantly higher by 2020 inside the MPA boundaries, there is currently no strong evidence for a reserve effect.

Highlights

Between 2013 and 2014 on the nearshore shallow reef flats before the regulations were approved [12]. These baseline surveys were not spatially representative of the areas covered in the 2016–2020 surveys and were not included in this study. This current study focuses on monitoring assemblage composition patterns of reproductively mature resource fish species throughout the full five-year monitoring period in an attempt to determine the efficacy of the Community Based Subsistence Fishing Area (CBSFA)
Results of this study suggest continuing annual surveys to evaluate long-term trends in order to better predict how resource fish assemblages may be changing within the current management regime
Determining the habitat types and benthic structures that are benefical to specific resource fishes at the Hā‘ena CBSFA is crucial in assessing any emerging patterns of assemblage composition

Summary

Introduction

Marine protected areas (MPAs) have been increasingly employed as an effective method for managing overfished nearshore coral reef ecosystems [1,2]. MPAs have been shown to increase fish biomass, diversity, and reproductive output within the protected area, as well as enhance adjacent areas via adult and larval spillover [1,3]. MPAs are not a panacea for overfished stocks, poor habitat quality, or ineffective management or enforcement [1,3,4,5,6]. The effectiveness of a MPA is often reliant on careful consideration of key features, such as size, shape, configuration, larval connectivity and recruitment, life-history traits, habitat types, enforcement, and community support [3,5,6,7]

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