Publication:
Comparison of handline, underwater visual census (UVC), and remote underwater video (RUV) used by fisheries-independent programs to assess reef fish abundance and biomass

dc.contributor.advisor Cruz Motta, Juan J.
dc.contributor.author López González, Leysa
dc.contributor.college College of Arts and Sciences - Sciences en_US
dc.contributor.committee Rosario, Aida
dc.contributor.committee Appeldoorn, Richard S.
dc.contributor.department Department of Marine Sciences en_US
dc.contributor.representative Huérfano Moreno, Víctor A.
dc.date.accessioned 2022-10-04T12:00:20Z
dc.date.available 2022-10-04T12:00:20Z
dc.date.issued 2022-08-08
dc.description.abstract Concerning declines in fish populations have ecological and socio-economic implications, jeopardizing the source of income and food security of millions of families. The purpose of fisheries independent programs is to implement cost-effective robust monitoring approaches necessary to assess spatiotemporal changes in fish structure and composition to help policymakers create appropriate management plans. Several methods have been employed by these programs resulting in different conclusions. We compared four different methods: two methods based on visual censuses (UVC: transect and roving), one method based on remote underwater videos (RUV), and handline (HL) to determine differences among the methods and establish whether the differences are complementary. All methods were simultaneously performed in a total of 13 sites on the east (Fajardo) for a total of 26 observations and 9 on the southwest (La Parguera Natural Reserve, LPNR) of Puerto Rico with a total of 42 observations. Multivariate analysis revealed that there are significant dissimilarities between the methods evidenced by the higher species diversity, abundances, and biomass observed in UVC and RUV. Higher spatiotemporal variability was associated with HL than with UVC and RUV, which were similar to each other. The method with the highest number of unique species was UVC (31) followed by HL (4) and RUV (3). Differences were also observed in fish groups assessed with HL detecting fewer species consisting mainly of the family Serranidae, while other important fish groups, such as individuals from families Scaridae and Acanthuridae, were observed in UVC and RUV. Univariate analysis for commercially important species also showed that UVC and RUV methods are more precise and time efficient than HL. A complementary association between that transect and roving was observed with the latter increasing the diversity observed during surveys. As a result, a multi-gear approach is recommended depending on the aims of the studies. UVC and RUV serve to gauge a broader range of fish structure and composition, while HL should be implemented in cases where age and sex data are necessary. en_US
dc.description.abstract La disminución de poblaciones de peces tiene implicaciones ecológicas y socioeconómicas poniendo en peligro la fuente de ingresos y seguridad alimentaria de millones de familias. El propósito de los programas independientes de pesquería es implementar monitoreos necesarios para evaluar los cambios espaciotemporales en la estructura y composición de las poblaciones de peces para ayudar a las agencias manejadores a crear planes apropiados. Estos programas han empleado varios métodos que han dado lugar a diferentes conclusiones, por esto comparamos cuatro métodos diferentes: dos censos visuales (UVC: transecto y nado aleatorio), un método de video (RUV) y pesca de mano (HL) para determinar las diferencias entre los métodos y establecer si estas diferencias son complementarias. Todos los métodos se realizaron simultáneamente en un total de 13 sitios en el este (Fajardo) para un total de 26 observaciones y 9 en el suroeste (Reserva Natural La Parguera) de Puerto Rico con un total de 42 observaciones. El análisis multivariado reveló que existen diferencias significativas entre los métodos evidenciados por la mayor diversidad, abundancia y biomasa de especies observadas en UVC y RUV. Se asoció mayor variabilidad espaciotemporal a HL que a UVC y RUV, que fueron más similares entre sí. El método con mayor número de especies únicas fue UVC (31) seguido por HL (4) y RUV (3). También se observaron diferencias en los grupos de peces evaluados con HL detectando menos especies principalmente de las familias Serranidae mientras que otros grupos importantes, como Scaridae y Acanthuridae, se observaron en UVC y RUV. El análisis univariado para especies comercialmente importantes también mostro que los métodos UVC y RUV son más precisos y eficientes en términos de tiempo de muestreo que HL. Se observo una asociación complementaria entre transecto y nado aleatorio, en el cual el nado aleatorio aumentó la diversidad. Como resultado se recomienda un enfoque de múltiples artes dependiendo de los objetivos de los estudios. UVV y RUV sirven para medir una gama más amplia de la estructura y composición del ensamblaje de peces, mientras que HL debe implementarse en los casos en que se necesitan datos de edad y sexo. en_US
dc.description.graduationSemester Fall en_US
dc.description.graduationYear 2022 en_US
dc.identifier.uri https://hdl.handle.net/20.500.11801/2969
dc.language.iso en en_US
dc.rights Attribution 3.0 United States *
dc.rights.holder (c) 2022 Leysa López-González en_US
dc.rights.uri http://creativecommons.org/licenses/by/3.0/us/ *
dc.subject Fisheries management en_US
dc.subject Fisheries independent programs en_US
dc.subject Handline en_US
dc.subject Underwater remote video en_US
dc.subject Visual census en_US
dc.subject.lcsh Coral reef fisheries--Research en_US
dc.subject.lcsh Reef fishes--Habitat--Monitoring--Technique en_US
dc.subject.lcsh Coral reef ecology--Research--Puerto Rico en_US
dc.subject.lcsh Reef fishes--Monitoring--Puerto Rico--Fajardo en_US
dc.subject.lcsh Reef fishes--Monitoring--Puerto Rico--Reserva Natural de La Parguera en_US
dc.subject.lcsh Biomass en_US
dc.title Comparison of handline, underwater visual census (UVC), and remote underwater video (RUV) used by fisheries-independent programs to assess reef fish abundance and biomass en_US
dc.type Thesis en_US
dspace.entity.type Publication
thesis.degree.discipline Marine Sciences en_US
thesis.degree.level M.S. en_US
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