The ocean and its inhabitants aren't static, so why do we manage them as if they are?

Ocean wildlife spotting tours don’t necessarily run year-round, instead only going out on the water when the primary species of interest is likely to be in the area.  You may go out and see so much wildlife you can barely count, or you may go out and return without seeing anything.  If you are a fisher, you may have a number of different spots you fish from, or you may use a ‘fish finder’ that points you to where they are most likely to be.  If you could see the smaller critters – the zooplankton, the larval stages of larger marine species (including some that eventually become largely sedentary), you would see that they too move.  In the ocean, creatures move.  Some move short distances, some may cross the global ocean.  

The ocean itself is highly dynamic – not just over space, but over time.  This variability in turn gives rise to variability in primary production - and this means that the preferred habitat and vital food resources also shift in time and space, giving rise to a patchy distribution of mobile species, like pelagic fishes, zooplankton, and sea turtles.


So, we have an ocean that is dynamic in both time and space.  We have species that are dynamic in abundance and distribution across time and space.  And we have people, using the ocean differently across time and space.  Yet we draw lines in the ocean, managing our use of it as if everything fitted into nice neat little boxes.  People like lines.  Lines denote boundaries, allowing us to categorise and compartmentalise the natural world neatly.  We have our Exclusive Economic Zones (EEZs) denoting countries territories.  We have marine protected areas that can look after key habitats.  But when dealing with the ocean we can see that the world doesn’t necessarily fit into such neat little boxes.  Management placed in a fixed area can work really well for some things but when dealing with mobile species – and indeed mobile people, we need something else to enhance static spatial management measures.  As outlined in a paper lead by Rebecca Lewison of San Diego State University, a team of researchers from around the globe (including myself) dynamic ocean management could be just what we need.

In a nutshell, dynamic ocean management is “management that changes in space and time in response to the shifting nature of the ocean and its users based on the integration of new biological, oceanographic, social, or economic data”.  On the face of it, it’s pretty straight forward, but think about it a little more and you can see that there is a lot of things that management would need to become adaptive to, and that some good data would be needed.  This is not an insurmountable task though.  As the paper highlights, there are a number of different types of dynamic ocean management already emerging.  Each differs slightly from each other in terms of complexity, data requirements, end-user dissemination, and so on.  For example, in British Columbia there are examples of salmon fisheries using stock estimates and in-season genetic analysis to ensure that different populations of chum salmon aren’t overexploited.  In Australia, bycatch of the critically endangered southern bluefin tuna in the Eastern Australian longline fishery with the use of a habitat model that is used to predict where the tuna’s habitat is.  Areas where the tuna are most likely to be are closed to fishers who do not have a quota to catch the tuna.  In the US, WhaleALERT uses acoustic buoys that detects whales in the Stellwagen Bank National Marine Sanctuary, and advises users of mandatory and voluntary speed limits designed to reduce ship strikes.  On the east coast of America it is even been used in a scallop fishery to reduce unwanted fish catch by the scallopers.

What these examples highlight is one of the beauties of dynamic ocean management – it’s near real-time approach.  Ocean users are only asked to restrict activities at the time and in the places where they are most likely to cause harm.  Australian fishers are only excluded from areas when the tuna are most likely to be there; vessels are only asked to slow down when whales are actually detected.  And then there is climate change.  We know from countless studies that marine populations are shifting ranges (see my post here for example).  Just as fisheries would need to adapt to the changing distributions of the critters they want to catch, so to do ocean managers.  In some cases, dynamic ocean management strategies may make this somewhat arduous task a little easier.  After all this is pro-active, not reactive management.

The concept of dynamic ocean management, be it for a mobile marine protected area, a fishery management tool, or even conflict avoidance tool, is still in its infancy.  The authors note that “applying the least labor intensive and most efficient technological and analytical approach will support long-term sustainability of programs by decreasing costs of continued maintenance”.  They also note amongst other things the importance of stakeholder participation in the process, and the need for more evaluations of the dynamic approaches already in effect.  Dynamic ocean management is not the one tool to solve the problems we have created in the ocean.  Nothing can be that.  But should the approach become implemented in more and more places, then it can play a role in conserving marine life – and allowing our continued sustainable use of the ocean.

The paper which was published in BioScience is freely available here.  Although the paper deals with a complex issue, it is well written and not overly technical in language.  Definitely worth a read (and I’m not just saying that because I was one of the authors!)

Image: Credit: Ben Ramirez/Flickr  (CC BY 2.0)