Over exploitation
Since the mechanisation of fisheries began in the late 19th Century humans have in many cases over-exploited fish stocks, leading to reduced populations of wild fish and diminishing incomes for the fishing industry. With a collapse of fish populations taking place in many parts of the planet, scientists are working to understanding the complex webs of marine biodiversity and ecosystems so that fishing effort can be managed in a sustainable way.
NOC is not a Fisheries research lab – our partners at CEFAS and Marine Scotland are the UK experts – but we do provide advice and research in a number of areas, particularly for deep-sea impacts.
Managed properly, fish should be a sustainable resource. This relies upon good governance and sound scientific advice. It is generally recognised that the present system of managing fisheries effort in the EU, the Common Fisheries Policy (CFP), has failed to either protect fish stocks or to protect the livelihoods of fishermen. The reasons are mainly to do with economic, social and political pressures being allowed to over-rule scientific advice, and a lack of understanding of how the ecosystem works as a whole. Fortunately the CFP is due for reform on an ‘ecosystems’ basis from 2013 – a process where NOC has provided input - and the European Commission has promised action to redress the failings of the current system. The evidence base for assessing the impact of fisheries, especially in deeper waters, relies in part on the science provided by NOC and our partners. Bottom trawling is by far the most damaging form of fisheries, and has been likened to ‘chopping down forests to catch the squirrels’. Our scientists have been able to demonstrate the impact of bottom trawling on fragile habitats such as cold-water coral reefs, and to demonstrate the very long time periods – in the order of decades or longer – that are required for the seabed to be restored to its pre-disturbance state.
We have also learned that not all changes in fish stocks are down to human over-exploitation. Rising sea temperatures have consequences for the distribution of fish larvae and prey species, leading stocks such as cod to move northwards into colder waters. Warmer water species are beginning to enter UK waters, along with less-welcome ‘alien invasive species’ carried from far away in the ballast water of ships. Ocean acidification (the reduction in ocean water pH caused by adding extra carbon dioxide through the burning of fossil fuels) is also expected to have consequences on marine ecosystems, although these are not yet fully understood.
Exploitation is not always about living marine resources. The oceans contain millions of tonnes of minerals and aggregates, today only exploited in shallow coastal waters, but as technology improves and land-based resources become depleted we are seeing the start of a new industry of deep-sea mining, especially for precious metals and the rare-earth minerals required for advanced electronic systems. NOC scientists are at the forefront of understanding deep ocean mineral deposits, in advising industry how to exploit the resources without severe ecological impacts, and also on the legal basis of claims to seabed resources.
Web resources:
- Reform of Common Fisheries Policy: http://ec.europa.eu/fisheries/reform/
- CEFAS marine fisheries pages: http://www.cefas.defra.gov.uk/our-science/fisheries-information.aspx
- Marine Scotland: http://www.scotland.gov.uk/Topics/marine
