The Demise of the marine Predators - Paper!

Poached Sharks in the Galapagos - click for detail.

From the Conclusions.

By using a modelling approach, our study outlined and confirmed 3 main trends about the impact of global fishing on ecosystems:

• the impacts are considerably greater for predators,
• are concentrated in coastal areas
• and have gradually expanded from northern to equatorial and southern waters.
  

We showed that the long-term operations of fisheries have severely reduced the biomass of predators in their historical fishing grounds, and that this trend is spreading rapidly to areas developed more recently.

To conclude, in the last decade many studies have reported the effects of fishing at multiple scales, through field studies, metrics, models and the analysis of time-series.
The one trend consistently observed is that fishing truncates a considerable portion of the biomass pyramid of ecosystems. Although the current global modelling approach focused on the effects of fishing only from the standpoint of direct biomass removal, the prediction of generalized predator decline implies widespread and fundamental changes to both the structure and the functioning of global marine communities.

Modelling the effects of fishing on the biomass of the world’s oceans from 1950 to 2006
Laura Tremblay-Boyer, Didier Gascue, Reg Watson, Villy Christensen, Daniel Pauly

Synopsis here, Abstract here and full open-source paper here.