Effects of climate‐driven primary production change on marine food webs: implications for fisheries and conservation

Abstract

Climate change is altering the rate and distribution of primary production in the world's oceans. Primary production is critical to maintaining biodiversity and supporting fishery catches, but predicting the response of populations to primary production change is complicated by predation and competition interactions. We simulated the effects of change in primary production on diverse marine ecosystems across a wide latitudinal range in Australia using the marine food web model Ecosim. We link models of primary production of lower trophic levels (phytoplankton and benthic producers) under climate change with Ecosim to predict changes in fishery catch, fishery value, biomass of animals of conservation interest, and indicators of community composition. Under a plausible climate change scenario, primary production will increase around Australia and generally this benefits fisheries catch and value and leads to increased biomass of threatened marine animals such as turtles and sharks. However, community composition is not strongly affected. Sensitivity analyses indicate overall positive linear responses of functional groups to primary production change.Responses are robust to the ecosystem type and the complexity of the model used. However, model formulations with more complex predation and competition interactions can reverse the expected responses for some species, resulting in catch declines for some fished species and localized declines of turtle and marine mammal populations under primary productivity increases. We conclude that climate-driven primary production change needs to be considered by marine ecosystem managers and more specifically, that production increases can simultaneously benefit fisheries and conservation. Greater focus on incorporating predation and competition interactions into models will significantly improve the ability to identify species and industries most at risk from climate change.

North Atlantic summers have warmed more than winters since 1353, and the response of marine zooplankton

“…Added variability in cod recruitment also exists as a consequence of stock specific responses to: (i) temperature [e.g., stocks at different positions in cod's distributional range responding differently (51) and/or changing their spawning locations (52)], (ii) wind and current induced changes in the distribution of cod eggs and larvae (53) and (iii) variable responses to NAO (46,54). Thus whereas in certain areas warming climate will lead to increased fishery yields (18) it appears that cod yields in the East Atlantic may be altered as a consequence of enhanced summer warming of waters at the time when their food, C. finmarchicus, is most sensitive to those changes. Such fluctuations in fish stocks have major economic and social consequences (7) and thus a detailed understanding of climate-induced changes, such as the inclusion of ecological knock-on effects (55), is required.…”

“…Therefore a key requirement for preserving biodiversity and supporting sustainable fishing is to understand the climatic effects in the lower levels of food webs (18). At present, general circulation models treat the marine environment in a simplified way, lacking the detail required for investigating the impacts of climate on marine ecosystems (7) beyond phytoplanktonic trophic levels.…”

Fitoplancton y zooplancton en el área marina protegida de Isla Gorgona, Colombia, y su relación con variables oceanográficas en estaciones lluviosa y seca

“…La importancia ecológica de esta comunidad radica, en que los patrones de variación temporal y espacial de su estructura, abundancia o biomasa pueden, en conjunto con otras variables físico-químicas de la columna de agua (e.g. temperatura, salinidad, oxígeno disuelto y nutrientes), modular la estructura de las comunidades bentónicas, así como la disponibilidad y viabilidad de recursos pesqueros comerciales de una región (Lalli & Parsons, 1997;Miller, 2004;Brown et al, 2010). isla Gorgona (2º58'10" N -78º11'05" W) es el área insular más extensa (13.3km 2 ) en la zona sur del Pacífico colombiano.…”

Marine projections of warming and ocean acidification in the Australasian region

“…Fabricius et al, 2011). Furthermore, it is likely that these changes will impact on the important ecosystems services that these marine environments provide such as fisheries, tourism, coastal protection and food security (Cooley et al, 2005;Brown, et al, 2010). In this context, projecting and understanding how Australia's climate may change, together with its potential impact on Australia's marine environment, is critical for the management of marine resources now and into the future.…”