Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery

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Introduction

Bycatch in small-scale fisheries

The Galapagos handline fishery

Aims of this study

Materials and Methods

Fishery observations

Bycatch estimates

Species composition

Prediction of bycatch sizes

Interview surveys

Results

Bycatch estimates

Landing composition

Bycatch composition and sizes

Interview surveys

Perception of historical changes of bycatch

Discussion

Species composition

Bycatch estimates

Historical changes of bycatch

Management suggestions

Conclusions

Supplemental Information

Fitting parameters of the length-weight relationship for species where these information were not available in the literature

Fitting parameters (a and b) of the length-weight relationship and the number of individuals measured (n).

DOI: 10.7717/peerj.995/supp-1

List of bycatch species that were mentioned by interviewed fishers once

Shows the species that were mentioned once by interviewees as well as the reasons to not land these species.

DOI: 10.7717/peerj.995/supp-2

Raw data of onboard observations about catch and bycatch of the Galapagos handline fishery 2012

The data show the fishing sites (numbered), the geographic position of the fishing site (latitude and longitude), the date of the fishing trip, the time when the fishers started their fishing activity and the duration of the activity at each fishing site. Indicated is the family and the species of the caught fish (no catch indicates sites where no fish was caught). Furthermore, it shows the total length of the caught fish (TL) and whether it belonged to landings or to bycatch. The catch category indicates what happened to the fish after it was caught (catch = landed, used as bait, discarded dead, discarded alive or personal use). Finally, it shows the fitting parameters of the length-weight relationship of each species and the estimated weight of each individual that was caught during the monitoring.

DOI: 10.7717/peerj.995/supp-3

Additional Information and Declarations

Competing Interests

The authors declare there are no competing interests.

Author Contributions

Johanna S. Zimmerhackel conceived and designed the experiments, performed the experiments, analyzed the data, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.

Anna C. Schuhbauer conceived and designed the experiments, performed the experiments, contributed reagents/materials/analysis tools, prepared figures and/or tables, reviewed drafts of the paper.

Paolo Usseglio performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, reviewed drafts of the paper.

Lena C. Heel conceived and designed the experiments, performed the experiments, prepared figures and/or tables, reviewed drafts of the paper.

Pelayo Salinas-de-León analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, reviewed drafts of the paper.

Human Ethics

The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):

The research was approved by the Galapagos National Park under the annual research plan of the Charles Darwin Foundation (POA 2012, number 86).

Field Study Permissions

The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers):

The research was approved by the Galapagos National Park under the annual research plan of the Charles Darwin Foundation (POA 2012, number 86).

Funding

This study was funded by the Galapagos Conservation Trust, the Lindblad National Geographic Fund (LX 04-14), WildAid, and the Helmsley Charitable Trust (2015PG-CON001). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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