The value of ecosystem services in global marine kelp forests.

While marine kelp forests have provided valuable ecosystem services for millennia, the global ecological and economic value of those services is largely unresolved. Kelp forests are diminishing in many regions worldwide, and efforts to manage these ecosystems are hindered without accurate estimates of the value of the services that kelp forests provide to human societies. Here, we present a global estimate of the ecological and economic potential of three key ecosystem services - fisheries production, nutrient cycling, and carbon removal provided by six major forest forming kelp genera (Ecklonia, Laminaria, Lessonia, Macrocystis, Nereocystis, and Saccharina). Each of these genera creates a potential value of between $64,400 and $147,100/hectare each year. Collectively, they generate between $465 and $562 billion/year worldwide, with an average of $500 billion. These values are primarily driven by fisheries production (mean $29,900, 904 Kg/Ha/year) and nitrogen removal ($73,800, 657 Kg N/Ha/year), though kelp forests are also estimated to sequester 4.91 megatons of carbon from the atmosphere/year highlighting their potential as blue carbon systems for climate change mitigation. These findings highlight the ecological and economic value of kelp forests to society and will facilitate better informed marine management and conservation decisions.

Redesigning harvest strategies for sustainable fishery management in the face of extreme environmental variability.

Short-lived, fast-growing species that contribute greatly to global capture fisheries are sensitive to fluctuations in the environment. Uncertainties in exact stock-environment relationships have meant that environmental variability and extremes have been difficult to integrate directly into fisheries management. We applied a management strategy evaluation approach for one of Australia's large prawn stocks to test the robustness of harvest control rules to environmental variability. The model ensemble included coupled environmental-population models and an alternative catchability scenario fitted to historical catch per unit effort data. We compared the efficacy of alternative management actions to conserve marine resources under a variable environment while accounting for fisher livelihoods. Model fits to catch per unit effort were reasonably good and similar across operating models (OMs). For models that were coupled to the environment, environmental parameters for El Niño years were estimated with good associated precision, and OM3 had a lower AIC score (77.61)  than the base model (OM1, 80.39), whereas OM2 (AIC 82.41) had a similar AIC score, suggesting the OMs were all plausible model alternatives. Our model testing resulted in a plausible subset of management options, and stakeholders selected a permanent closure of the first fishing season based on overall performance of this option; ability to reduce the risk of fishery closure and stock collapse; robustness to uncertainties; and ease of implementation. Our simulation approach enabled the selection of an optimal yet pragmatic solution for addressing economic and conservation objectives under a variable environment with extreme events.

Rediseño de las Estrategias de Captura para el Manejo de Pesquerías Sustentables de Caraa una Variabilidad Ambiental Extrema Resumen Las especies de vida corta y rápido crecimiento que contribuyen enormemente a la captura mundial de las pesquerías son sensibles a las fluctuaciones en el ambiente. La incertidumbre en torno a las relaciones exactas entre el ambiente y el stock ha representado una dificultad para integrar directamente la variabilidad y los extremos ambientales a la gestión de las pesquerías. Aplicamos un enfoque de evaluación de estrategia de manejo (EEM) para uno de los stocks de camarones de Australia y así analizar la solidez de las reglas de control de captura para la variabilidad ambiental. El ensamblado modelo incluyó modelos ambientales-poblacionales emparejados y un escenario alternativo de capturabilidad ajustado a los datos históricos de esfuerzo de captura por unidad. Comparamos la eficiencia de acciones alternativas de manejo para conservar los recursos marinos bajo un ambiente variable teniendo en cuenta el sustento de los pescadores. Los ajustes del modelo para el esfuerzo de captura por unidad fueron razonablemente buenos y similares en los modelos operantes (MO). Para los modelos que estuvieron emparejados con el ambiente, los parámetros ambientales para los años de El Niño estuvieron estimados con una buena precisión asociada, y el MO3 tuvo un puntaje AIC menor (77.61) que el modelo base (MO1, 80.39), mientras que el MO2 (AIC 82.41) tuvo un puntaje AIC similar, lo que sugiere que los MO eran todos modelos plausibles alternativos. Nuestro análisis de los modelos resultó en un subconjunto plausible de opciones de manejo, y los actores seleccionaron un cierre permanente de la primera temporada de pesca con base en el desempeño general de esta opción, la habilidad para reducir el riesgo del cierre de la pesquería y el colapso del stock, la solidez ante las incertidumbres y la facilidad de implementación. Nuestra estrategia de simulación permitió la selección de una solución óptima pero pragmática para abordar los objetivos económicos y de conservación bajo un ambiente variable con eventos extremos.