Short-Term Fidelity, Habitat Use and Vertical Movement Behavior of the Black Rockfish Sebastes schlegelii as Determined by Acoustic Telemetry.

Yingqiu Zhang,Qinzeng Xu,Josep Alós,Hui Liu,Hongsheng Yang,Qiang Xu,Jeffrey Buckel

doi:10.1371/journal.pone.0134381

Abstract

The recent miniaturization of acoustic tracking devices has allowed fishery managers and scientists to collect spatial and temporal data for sustainable fishery management. The spatial and temporal dimensions of fish behavior (movement and/or vertical migrations) are particularly relevant for rockfishes (Sebastes spp.) because most rockfish species are long-lived and have high site fidelity, increasing their vulnerability to overexploitation. In this study, we describe the short-term (with a tracking period of up to 46 d) spatial behavior, as determined by acoustic tracking, of the black rockfish Sebastes schlegelii, a species subject to overexploitation in the Yellow Sea of China. The average residence index (the ratio of detected days to the total period from release to the last detection) in the study area was 0.92 ± 0.13, and most of the tagged fish were detected by only one region of the acoustic receiver array, suggesting relatively high site fidelity to the study area. Acoustic tracking also suggested that this species is more frequently detected during the day than at night in our study area. However, the diel detection periodicity (24 h) was only evident for certain periods of the tracking time, as revealed by a continuous wavelet transform. The habitat selection index of tagged S. schlegelii suggested that S. schlegelii preferred natural reefs, mixed sand/artificial reef bottoms and mixed bottoms of boulder, cobble, gravel and artificial reefs. The preference of this species for the artificial reefs that were recently deployed in the study area suggests that artificial seascapes may be effective management tools to attract individuals. The vertical movement of tagged S. schlegelii was mostly characterized by bottom dwelling behavior, and there was high individual variability in the vertical migration pattern. Our results have important implications for S. schlegelii catchability, the implementation of marine protected areas, and the identification of key species habitats, and our study provides novel information for future studies on the sustainability of this important marine resource in eastern China.

Highlights

The historical exploitation of naturally reproducing fish populations has led to the overexploitation of many stocks and serious effects on natural systems, societies and economies worldwide [1,2,3,4,5,6]
Fish movement is rarely considered in stock assessments, movement is a key parameter in the population structure of many species (e.g., Atlantic bluefin tuna Thunnus thynnus [12]) and the potential survival benefits provided by marine protected areas (MPAs) [13]
The spatial coverage of seagrass was quantified by a Simrad EY60 split-beam device run at 200 kHz along closely spaced routes parallel to the shelf in the shallow waters of the Qiansan Islets (< 20 m deep, see S3 Fig for visualization of the trajectory), and the results suggested that the seagrass was mainly distributed in shallower waters < 15 m deep (Fig 1 (C))

Summary

Introduction

The historical exploitation of naturally reproducing fish populations has led to the overexploitation of many stocks and serious effects on natural systems, societies and economies worldwide [1,2,3,4,5,6]. A primary factor in the overexploitation of marine resources is poor spatial knowledge of fish stocks [7,8,9,10,11]. An understanding of the spatial dimension of the fish stock is integral to the sustainability of fisheries. Such understanding enables us to identify the expected distribution of resources or the consequences of selective fishing [14,15,16]. Traditional fishery management is typically based on homogeneous scenarios, and the spatial component is frequently overlooked [7,18]

Methods

Results

Conclusion