A positive effect of climate change that is helping to support a £30m industry has been uncovered by new research. Ocean warming in UK waters is increasing stocks of the great scallop Pecten maximus, according to the study published in the journal Marine Biology. However the researchers have warned that further rises in water temperatures could have the opposite effect on scallops and better management of these fisheries is needed to protect sensitive seabed habitats.

The findings have emerged from the analysis of 20 years of data by scientists at Bangor University and the Universities of York and Liverpool. Dr Bryce Beukers-Stewart, from the University of York's Environment Department, said: "It's great to provide some good news about one of our fisheries for a change. However, scallop fisheries are difficult to manage and have a history of boom and bust around the world. "We must ensure this valuable resource is fished in a way that maximises yields and reproduction to ensure healthy stocks in the future."

Dr Samuel Shephard, who led the analysis and is now at the Galway-Mayo Institute of Technology, said: "Temperature can be a strong driver of growth and reproduction in scallops, and this was expressed across almost two decades of ocean warming. It was disconcerting to see first-hand how climate change may affect important fisheries."

The study focused on the scallop fishery around the Isle of Man which has been surveyed since 1990. It found that numbers of young scallops each year were, on average, positively related to water temperature in the spring when they were spawned. The gonads of adult scallops were also larger, indicating higher egg production, in warmer years.

While the research suggests that climate change is helping support scallop populations they face other pressures including dredging on sensitive seabed habitats. Professor Mike Kaiser, from the School of Ocean Science at Bangor University, said: "The scallop industry in the UK has the potential to be even more valuable in the future, but this will only happen if European and national legislation is introduced to control effort and to deal with the issue of latent capacity in the fleet. These climate-related benefits could easily be erased by an uncontrolled increase in landings and fishing activity."

A continued growth in ocean temperatures and greenhouse gas emissions, raising the acidity levels of the water, could also eventually affect the ability of scallops to form proper shells and cause widespread mortality.

Journal reference:
   1. Shephard et al. Strengthening recruitment of exploited scallops Pecten maximus with ocean warming. Marine Biology, 2009; DOI: 10.1007/s00227-009-1298-7

(ScienceDaily*, 13/10/2009)

*Adapted from materials provided by University of York