Herramientas basadas en indicadores tróficos para la implementación del enfoque ecosistémico en pesquerías con escasez de datos: ejemplos de Argelia y Bahía Bou-Ismail

Over the past decade, the Algerian government has undertaken several incentives financed by state subsidies, via a range of development plans for fishing activities. Although these have led to the growth and modernization of the fishing fleet and the creation of various jobs, this increased fishing pressure has not maximized production as anticipated. In fact, catch is decreasing, and there are clear signs of stock overexploitation for several species, particularly sardines, for which catches have fallen dramatically. This study analyses the impact of fishing from an ecosystem perspective, with a view to the implementation of ecosystem approach to fishery management (EAFM) at the level of Algerian fisheries. To this end, a series of trophic indicators are used. The analysis shows that ecosystems at both national level and in the Bou-Ismail Bay are excessively exploited, and are altered by overexploitation and probably eutrophication. This situation is demonstrated in particular by the decrease in the average trophic level of catch, which is synonymous with “Fishing Down Marine Food Webs” (FDMW).Durante la década pasada, el gobierno argelino puso en marcha varios incentivos de financiación estatal, a través de una serie de planes de desarrollo para actividades pesqueras. A pesar de que este hecho ha originado crecimiento y modernización en la flota pesquera, además de la creación de puestos de trabajo, este aumento de la presión pesquera no ha permitido aumentar la producción pesquera como se había previsto. De hecho, las capturas están decreciendo y hay claros signos de sobreexplotación en varias especies, particularmente la sardina, para la cual las capturas han descendido drásticamente. Este estudio analiza el impacto de la pesca desde una perspectiva ecosistémica, con vistas a implementar el enfoque ecosistémico en la ordenación pesquera argelina. Se utilizan una serie de indicadores tróficos para este fin. El análisis muestra que los ecosistemas están muy explotados, alterados por la sobreexplotación y probablemente eutrofizados, tanto a nivel nacional como en la bahía de Bou-Ismail. Esta situación ha quedado demostrada concretamente por el descenso en el nivel trófico medio de las capturas, que significa la pesca de los niveles inferiores de la cadena trófica marina

The Missing Layers: Integrating Sociocultural Values Into Marine Spatial Planning

Marine Spatial Planning (MSP) is a relatively new approach to ocean management and has been widely implemented worldwide. Ideally, MSP should be established as a public process that analyzes and distributes human activities across space and time to achieve ecological, economic and social goals, which historically have been accomplished exclusively in the political arena. However, in most cases MSP seems to be driven primarily by economic interests rather than by sociocultural goals. In this paper, we discuss how integrating the missing sociocultural layers into MSP can help to reduce governance rigidity, promote adaptability in decision-making, support environmental justice, and improve MSP acceptance and uptake. In particular, we focus on identifying possible points of connection between MSP and frameworks based on social-ecological system theory, including co-management and other democratic and empowering alternatives. We conclude by proposing a new definition of the MSP process that is more inclusive, and mindful of users’ rights and sociocultural objectives. If we bridge the gap between the dominant economic rhetoric and a de facto sociocultural-ecological system approach, we are likely to improve the chances of the MSP process succeeding on both the human and nature fronts.Postprin

A Hierarchical Bayesian Modeling Approach for the Habitat Distribution of Smooth Dogfish by Sex and Season in Inshore Coastal Waters of the US Northwest Atlantic

The Smooth Dogfish Mustelus canis is an abundant, small coastal shark occurring along the U.S. Atlantic coast. Despite being targeted by a directed fishery and having recently undergone a stock assessment that found the population neither overfished nor experiencing overfishing, little is known about the spatial and temporal distribution of this species. Here, we used catch data from the spring and fall Northeast Area Monitoring and Assessment Program\u27s fishery-independent trawl surveys conducted between 2007 and 2016 and various environmental factors to perform hierarchical Bayesian modeling as a first attempt to spatially predict adult Smooth Dogfish CPUE in U.S. northwest Atlantic Ocean waters by sex and season. Relevant environmental variables differed between both sexes and seasons. Male and female CPUEs were similarly associated with lower salinity and shallower depth in the spring. During fall, male CPUE was associated with sea surface temperature and bottom rugosity, and female CPUE was associated with chlorophyll-a concentration, bottom rugosity, and year. Habitat modeling results predicted that areas of high male and female CPUEs would overlap during spring but strongly diverge during fall, when greater predicted CPUEs for males were distributed considerably farther north. These results suggest sexual segregation among Smooth Dogfish during fall, with the springtime overlap in distribution coinciding with the pupping and mating season in this population. This difference in distribution during fall may allow for a male-only directed fishery for Smooth Dogfish in the northern extent of the species\u27 range in waters near southern New England and Georges Bank

Modelagem espacial bayesiana para riqueza de elasmobrânquios do extremo sul do Brasil

Compreender a distribuição espacial de espécies vulneráveis a exploração pesqueira pode subsidiar ações de manejo e conservação. O objetivo deste estudo foi mapear possíveis habitats essenciais para riqueza de elasmobrânquios no sul do Brasil. Os dados são oriundos de cruzeiro científico realizado em fevereiro de 2005 entre o arroio Chuí (33°45'S) e o Cabo de Santa Marta Grande (28°36'S). As informações disponíveis são posições georeferenciadas de 64 estações oceanográficas, a quantificação das capturas de elasmobrânquios e teleósteos com pesca de arrasto de fundo e o registro dos parâmetros ambientais de profundidade, temperatura e salinidade. Os dados foram ajustados a um Modelo Linear Generalizado (GLM) Bayesiano via INLA (Integrated Nested Laplace Approximations) e módulo SPDE (Stochastic Partial Differential Equations), implementados no software R. A qualidade de ajuste e o poder preditivo do modelo foram avaliados mediante DIC (Deviance Information Criterion), WAIC (Watanabe-Akaike Information Criterion) e LCPO (Logarithm Conditional Predictive Ordinate). Foram registradas 16 espécies de elasmobrânquios, cujo número variou de 1 à 9 por lance. No modelo proposto, o efeito espacial e as variáveis ambientais foram relevantes para explicar a variação da riqueza de elasmobrânquios na costa do Rio Grande do Sul. Esta abordagem estatística permite estimar a probabilidade de ocorrência das espécies em áreas não amostradas, levando em conta a autocorrelação espacial dos dados e o conhecimento dos valores das co-variávies ambientais

Modelling spatially sampled proportion processes​​

Many ecological processes are measured as proportions and are spatially sampled. In all these cases the standard procedure has long been the transformation of proportional data with the arcsine square root or logit transformation, without considering the spatial correlation in any way. This paper presents a robust regression model to analyse this kind of data using a beta regression and including a spatially correlated term within the Bayesian framework. As a practical example, we apply the proposed approach to a spatio-temporally sampled fishery discard dataset