A geostatistical approach for the stock assessment of the edible sea urchin, Paracentrotus lividus, in four coastal zones of Southern and West Sardinia (SW Italy, Mediterranean Sea)

Addis, Piero; Secci, Marco; Manunza, Andrea; Corrias, Stefano; Niffoi, Alessio; Cau, Angelo

doi:10.1016/j.fishres.2009.07.008

Cited by 20 publications

(13 citation statements)

References 33 publications

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“…Gaussian and spherical models describe the spatial structure of sea urchins in the area, confirming a previous study conducted in Sardinia (Addis et al 2009). …”

Section: Discussionsupporting

confidence: 87%

“…values at one location are independent of values at neighbouring locations. Although conventional approaches are equally valid, they involve some limitations in the usefulness of the ecological data gathered for biomass estimates, in terms of spatial scales and the setting of their confidence limits (Addis et al 2009). In this respect, geostatistical techniques are more powerful tools for estimating the spatial distribution of marine benthic communities than conventional statistical methods because they explicitly consider spatial correlation between observations (Warren 1998, Rueda 2001.…”

Section: Introductionmentioning

confidence: 99%

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Spatial distribution patterns and population structure of the sea urchin <i>Paracentrotus lividus</i> (Echinodermata: Echinoidea), in the coastal fishery of western Sardinia: a geostatistical analysis

Addis¹,

Secci²,

Angioni³

et al. 2011

Sci. Mar.

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SUMMARY: The identification of appropriate spatial distribution patterns for the observation, analysis and management of stocks with a persistent spatial structure, such as sea urchins, is a key issue in fish ecology and fisheries research. This paper describes the development and application of a geostatistical approach for determining the spatial distribution and resilience of the population of the sea urchin Paracentrotus lividus in a fishing ground of western Sardinia (western Mediterranean). A framework combining field data collection, experimental modelling and mapping was used to identify the best-fit semivariogram, taking pre-fishing and post-fishing times into consideration. Variographic analyses indicate autocorrelation of density at small distances, while the isotropic Gaussian and spherical models are suitable for describing the spatial structure of sea urchin populations. The point kriging technique highlights a generally patchy population distribution that tends to disappear during the fishing season. Kriging maps are also useful for calculating predictable stock abundances, and thus mortality rates, by class diameters within six months of fishing. We conclude that the framework proposed is adequate for biomass estimation and assessment of sea urchin resources. This framework can therefore be regarded as a useful tool for encouraging a science-based management of this fishery.Keywords: Paracentrotus lividus, spatial distribution, geostatistics, biomass estimation, management, Western Mediterranean. RESUMEN: Modelo de distribución espacial y estructura poblacional del erizo de mar Paracentrotus lividus (Echinodermata: Echinoidea) en la pesquería costera de Cerdeña occidental (Mediterráneo occidental): aplicación de un enfoque geoestadístico. -La identificación de modelos de distribución espacial apropiados para la observación, análisis y ordenación de los stocks con estructura espacial constante, como los erizos de mar, son temas clave en la ecología de los peces e investigación de pesquerías. El presente trabajo describe el desarrollo y aplicación de un enfoque geoespacial para determinar la distribución espacial y resistencia de la población del erizo de mar (Paracentrotus lividus) en un área pesquera al oeste de Cerdeña (Mediterráneo occidental). Se utilizó un marco que combina la recolección de datos de campo, modelos experimentales y mapas, para identificar el mejor ajuste en el semivariograma, teniendo en cuenta tiempos antes y después de la pesca. Los análisis variográficos indican una autocorrelación para la densidad a pequeñas distancias, mientras que los modelos isotrópicos Gaussianos y esféricos son apropiados para describir la estructura espacial de las poblaciones del erizo de mar. La técnica del kriging puntual destaca una distribución desigual de la población que tiende a desaparecer durante la temporada de pesca. Los mapas que utilizan kriging son también útiles para calcular una abundancia fiable del stock, y por lo tanto tasas de mortalidad por clases de diámetro en un período de s...

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“…Gaussian and spherical models describe the spatial structure of sea urchins in the area, confirming a previous study conducted in Sardinia (Addis et al 2009). …”

Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Spatial distribution patterns and population structure of the sea urchin <i>Paracentrotus lividus</i> (Echinodermata: Echinoidea), in the coastal fishery of western Sardinia: a geostatistical analysis

Addis¹,

Secci²,

Angioni³

et al. 2011

Sci. Mar.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The appropriateness of the models fitted in the variographic analysis and kriging interpolations was evaluated through jack‐knife cross‐validation, which sequentially excludes one sampling point and uses the remaining data to estimate it (Addis et al., ; Isaaks & Srivastava, ). The observed and estimated biomass values were fitted to a linear regression (Addis et al., ; Castrejón et al., ). Departures from a one‐to‐one line through the origin indicate model inadequacy, and differences between the estimated and hypothetical regression co‐efficient ( b = 1) and axis intercept ( a = 0) were tested by a Student's t ‐test (Sachs, ).…”

Section: Methodsmentioning

confidence: 99%

Spatio‐temporal variation in biomass of the deep‐sea red crab Chaceon affinis in Gran Canaria Island (Canary Islands, Eastern‐Central Atlantic)

2017

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The spatial and temporal biomass distribution of Chaceon affinis and its vulnerability to fishing activity in Gran Canaria (Canary Islands) were investigated. The first goal was to assess the influence of the slope steepness and substrate on the size of crab patches, size of the crabs, and crab biomass. The second goal was to evaluate spatial and temporal variation in the biomass over a 15‐month period. The last goal was to assess the influence of fishing activity upon the reduction in the biomass over the same 15‐month period. Only two or three locations in the sampling area generated high‐biomass contour patches. When these patches were superimposed on the isobath lines, they were coincident with the main depth range described for the species in the area. The map of the biomass values clearly showed three structures with cores of the highest biomass in both muddy and rocky‐muddy areas. The biomass was higher on muddy than on rocky‐muddy bottoms. Biomass was twice as high when steepness was reduced to one third between isobaths of 500 and 900 m. The size of crab patches increases linearly with the decrease in slope steepness. The spatial structure of crabs remained fairly stable over time, showing that biomass changes with depth over time. Maps of the estimated biomass values over the 15‐month period showed the same two main patches over time with the cores of highest biomass separated by a distance of between 4.2 and 4.5 km. Although the bathymetric distribution by sexes showed temporal changes, with a displacement to deeper areas made by both sexes over the studied period, only a partial temporal segregation between males and females was observed. During the study period, crabs underwent a significant decline in biomass and this was consistent with the combined catches of both commercial and experimental fishing in the area. Due to its low mobility, C. affinis is highly vulnerable to local depletion by intensive fishing efforts.

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“…Due to the high market demand for its gonads in both Mediterranean and non-Mediterranean areas (Pais, Chessa, Serra, Ruiu, Meloni & Donno 2007), natural populations are exposed to over fishing in many European coastal areas. This often causes a sharp decline in the abundance of wild stocks (Boudouresque & Verlaque 2007;Pais et al 2007;Addis, Secci, Manunza, Corrias, Niffoi & Cau 2009).…”

Section: Introductionmentioning

confidence: 99%

Effects of on-demand feeding on sea urchin larvae (Paracentrotus lividus ; Lamarck, 1816), development, survival and microalgae utilization

et al. 2016

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This study compared the growth of sea urchin Paracentrotus lividus larvae cultured using two different rearing methods: a variable method based on a variable amount of feed (microalgae) and seawater exchange (30% or 50%) established according to the phytoplankton concentration in the larval cultures and a fixed method characterized by a fixed amount of feed and seawater exchange. Three microalgae diets, Isochrysis sp. (Tahitian strain, T-Iso), Chaetoceros gracilis and a 50:50 mixed diet, were tested with both rearing methods. Larval development and survival were assessed at the 6-arm pluteus stage (P6), competence (Cp) and metamorphosis (Mt). Data showed that the variable method reduced the requirements for phytoplankton and seawater exchange. Indeed, through the optimization of feed rations, it was possible to reduce the production of debris and settled phytoplankton, minimizing the need for water exchanges. Higher larval survival resulted at Cp and Mt stages for those reared with the variable method as opposed to the fixed one. Survival and development were also influenced by the tested dietary treatments: at Mt stage, the mixed diet resulted in a higher larval survival (63.3 AE 8.9%) than T-Iso (19.7 AE 12.1%) and C. gracilis (23.4 AE 15.1%) (P < 0.05). These results suggest that the use of the variable method improves the larval survival and development and also it reduces resource consumption (phytoplankton, seawater use and work effort), which in turn could potentially improve the hatchery production of P. lividus. Effects of on-demand feeding on sea urchin larvae B Gianni et al.

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A geostatistical approach for the stock assessment of the edible sea urchin, Paracentrotus lividus, in four coastal zones of Southern and West Sardinia (SW Italy, Mediterranean Sea)

Cited by 20 publications

References 33 publications

Spatial distribution patterns and population structure of the sea urchin <i>Paracentrotus lividus</i> (Echinodermata: Echinoidea), in the coastal fishery of western Sardinia: a geostatistical analysis

Spatial distribution patterns and population structure of the sea urchin <i>Paracentrotus lividus</i> (Echinodermata: Echinoidea), in the coastal fishery of western Sardinia: a geostatistical analysis

Spatio‐temporal variation in biomass of the deep‐sea red crab Chaceon affinis in Gran Canaria Island (Canary Islands, Eastern‐Central Atlantic)

Effects of on-demand feeding on sea urchin larvae (Paracentrotus lividus ; Lamarck, 1816), development, survival and microalgae utilization

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