Effects of Fisheries on Seabird Community Ecology

Wagner, Eric L.; Boersma, P. Dee

doi:10.1080/10641262.2011.562568

Cited by 42 publications

(30 citation statements)

References 107 publications

(149 reference statements)

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“…The effect of fisheries on Southern Ocean seabird populations through the harvest of intermediate trophic level species remains largely unexplored (Wagner & Boersma 2011). Studies using predator− prey models or ecosystem models remain largely theo retical (May et al 1979) and often suffer from a shortage of empirical data (Hill et al 2006).…”

Section: Effects Of Fisheries Bycatch On Demography and Population Dymentioning

confidence: 99%

Effects of climate change and fisheries bycatch on Southern Ocean seabirds: a review

Barbraud¹,

Rolland²,

Jenouvrier³

et al. 2012

Mar. Ecol. Prog. Ser.

136

129

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Over the last century, major climate changes and intense human exploitation of natural living resources have occurred in the Southern Ocean, potentially affecting its ecosystems up to top marine predators. Fisheries may also directly affect seabirds through bycatch and additional food resources provided by discards. The past 20 yr of research has seen an increasing number of studies investigating the effects of climate change and fisheries activities on Southern Ocean seabirds. Here, we review these studies in order to identify patterns in changes in distribution, phenology, demography and population dynamics in response to changes in climate and fisheries bycatch. Shifts in distribution and breeding phenology were documented in parallel to increases in sea-surface temperatures and changes in sea-ice cover. Above all warm sea-surface temperatures negatively affected demographic parameters, although exceptions were found. Relationships suggest non-linear effects of sea-ice cover on demographic parameters and population dynamics, with optimum sea-ice cover conditions appearing to be the rule. Fishing efforts were mainly negatively related to survival rates, and only for a few species positively related to breeding success. A handful of studies found that chronic mortality of immature birds due to fisheries negatively affected populations. Climate factors and fisheries bycatch may simultaneously affect demographic parameters in a complex way, which can be integrated in population models to project population trajectories under future climate or fisheries scenarios. Needed are studies that integrate other environmental factors, trophic levels, foraging behaviour, climate−fisheries interactions, and the mechanisms underlying phenotypic plasticity, such as some pioneering studies conducted elsewhere.

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Section: Effects Of Fisheries Bycatch On Demography and Population Dymentioning

confidence: 99%

Effects of climate change and fisheries bycatch on Southern Ocean seabirds: a review

Barbraud¹,

Rolland²,

Jenouvrier³

et al. 2012

Mar. Ecol. Prog. Ser.

136

129

View full text Add to dashboard Cite

show abstract

“…These foraging opportunities can appear beneficial to seabirds, as fishery discards may comprise a substantial part of their diet (e.g. Freeman and Wilson, 2002;Wagner and Boersma, 2011). However, there can also be negative consequences to this behaviour, e.g.…”

Section: Introductionmentioning

confidence: 97%

Controlling trawler waste discharge to reduce seabird mortality

et al. 2012

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“…Morissette et al (2012) used the mTL C and derived a new indicator, the mean trophic level of marine mammal consumption, to evaluate the trophic levels targeted by fisheries with those consumed by marine mammals in several ecosystems. This approach is intriguing because elucidating the direct and indirect interactions between fisheries and marine predators is of great interest to fisheries scientists and managers globally (e.g., Read 2008;Wagner and Boersma 2011). In this way, these indicators may be useful in screening for ecosystems or latitudes where there may be a potential for conflict among predators and fisheries for similar prey items.…”

Section: Introductionmentioning

confidence: 98%

Are We Catching What They Eat? Moving Beyond Trends in the Mean Trophic Level of Catch

Rountos

Frisk²,

Pikitch³

2015

Fisheries

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Fisheries | www.fisheries.org 377 ¿Estamos pescando lo que ellos comen? Más allá de las tendencias del nivel trófico medio de la captura El nivel trófico promedio de las capturas pesqueras se utiliza comúnmente para describir y evaluar las tendencias de las pesquerías a través del tiempo. Si bien su utilidad como indicador de la salud relativa de las pesquerías en ecosistemas marinos ha sido un tema de intenso debate, el cálculo de esta métrica es claro. En el presente artículo se aplicó este indicador junto con uno nuevo, el nivel trófico promedio del consumo de los depredadores, a 40 modelos Ecopath alrededor del mundo. Juntas, estas dos medidas fueron utilizadas para detectar dónde las pesquerías y los depredadores marinos pueden estar incidiendo en niveles tróficos similares de las presas. De forma global, los niveles tróficos promedio capturados por todas las pesquerías de escama fueron similares a aquellos consumidos por mamíferos marinos, pero sensiblemente más altos que aquellos consumidos por aves marinas y grandes peces depredadores. No se encontraron diferencias significativas entre los niveles tróficos que utilizan las pesquerías de peces forrajeros y los depredadores. Estos indicadores pueden aportar información útil para el manejo de las pesquerías basado en el ecosistema, especialmente cuando la información sobre los depredadores y las interacciones con las pesquerías es limitada o no está disponible.The mean trophic level of fisheries catch is commonly used to describe and assess temporal trends in fisheries. Though its value as an indicator to evaluate the relative health of fisheries in marine ecosystems has been hotly debated, the metric calculated is clear. We applied this indicator along with a relatively new indicator, the mean trophic level of predator consumption, to 40 Ecopath models around the world. Together, these measures were used to detect where fisheries and marine predators may be targeting similar trophic levels of prey. Globally, the mean trophic levels caught by all fisheries and finfish fisheries were similar to those consumed by marine mammals but significantly higher than those consumed by seabirds and large predatory fish. We found no significant differences between the median trophic levels targeted by forage fisheries and predators. These indicators can inform ecosystembased management, especially when information on predators and fishery interactions are limited or unavailable.

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Effects of Fisheries on Seabird Community Ecology

Cited by 42 publications

References 107 publications

Effects of climate change and fisheries bycatch on Southern Ocean seabirds: a review

Effects of climate change and fisheries bycatch on Southern Ocean seabirds: a review

Controlling trawler waste discharge to reduce seabird mortality

Are We Catching What They Eat? Moving Beyond Trends in the Mean Trophic Level of Catch

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