We’ve caught a couple of pre-reports on this, but now the full paper is available for all to read at PLoS 1. The report is based on historical fish landings reported from the Firth. This sees a healthy and diverse fishery in the early 19th century. After this date the fisheries effort intensified, and commercial landings for each species targeted in turn is seen to go through a boom followed within a few decades with collapse.

The only commercial fisheries that remain today are reported to be for Nephrops and scallops (Pecten maximus, Pectinidae). The report damns the fishing industry for forcing a repeal of the trawl ban in 1984 that had been put in place since 1889. It further argues that modern intensive Nephrops fisheries are preventing the recovery of other fish stocks.

Thurstan RH, Roberts CM (2010) Ecological Meltdown in the Firth of Clyde, Scotland: Two Centuries of Change in a Coastal Marine Ecosystem. PLoS ONE 5(7): e11767. doi:10.1371/journal.pone.0011767

Oil spills, chemical weapons, global warming, even toxic octopuses in this week’s episode. Just when you thought it couldn’t get any worse, a report has surfaced over the last two days that the levels of global marine primary production are in free-fall. This story links with our report last week, that phytoplankton actually start to bloom in the winter, when turbulence reduces the density of predators (Acepted theory of algal blooms wrong). This week global warming is blamed for increasing the temperature of surface waters, causing them to become more stratified, and reducing the chance of mixing with deeper cold water masses. The worrying thing is that this week’s report is based on evaluation of historic data for phytoplankton levels in seawater, so it looks like the feedback loop we predicted last week is already picking up speed… Our second article is a calibration exercise to allow us to quantify phytoplankton blooms from space more accurately, I hope that this will show up some errors in the estimates made in the first paper.
Read the rest of this entry »