Food for thought…

1. Food for thought… The sustainability of life our seas

2. Session outline • The importance of life in our seas and why we need to understand it • Food webs: from theory to practice • Interactive food web game: food for thought… • How can we manage our seas for the future? A focus on sustainable development

3. Coral Reefs Marine Environment Diversity of life Rocky Shores Deep Seas Open Oceans

4. Climate change and oxygen • Just like trees on land, tiny phytoplankton (microscopic plants) in the oceans absorb carbon dioxide from the atmosphere • Generates over 50% of the oxygen we breathe

5. Important source of protein • Building blocks of growth and repair in the body • Many of the worlds coastal populations rely on fishing as both a livelihood and source of food • Overfishing crisis?

6. Why it’s important to understand life in our seas • The actions of humans have an impact on human use of the seas, the life that lives there and the habitats that support this life • Marine pollution (sewage release, heavy metals, oil spills) • Overfishing (food web disruption) • Climate change (habitats and where plants and animals can survive) • One way of predicting human impact on the marine environment is to use food webs

7. Food webs: from theory to practice • Normally start off with a food chain… e.g. North Sea Primary producers Secondary consumers Top predators Primary consumers Light Photosythesisers Herbivores Carnivores Carnivores Cod Sun Phytoplankton Zooplankton Herring Energy transfer Energy loss MRS. GREN

9. But it’s a bit more complicated than this… • The feeding relationships between organisms in a community are better represented as a food web, because: • An organism may be the prey/predator of more than one other organism • We can see how nutrients are recycled in the food web, which is important for producers • Ecologists can better predict the effects of removing, or reducing the abundance of, one or more organisms in the community

10. Interactive food web game:Food for thought… • Split into pairs. • Person 1 is given an organism card from one of the food for thought … packs provided • Person 2 has to help connect that organism to others in the food web using the key facts on the back of the cards and the linking threads provided. Think about how the organisms feed • Place threads in the bottom of the card if eaten/used and vice versa. Try and work out which way energy is being transferred • We will then look at the effects of some real life scenarios to show that an effect on one organism disrupts every other organism in the food web

11. How can we manage our seas for the future? A focus on sustainable development What steps would you take?

12. How can we manage our seas for the future? A look at fishing Are fishing quotas the answer? • Set limits on how many tonnes of each fish species can be caught and ‘landed’ each year • PROBLEMS: fishing catches lots of different fish species all in one go. ‘Like dragging a net across a field of animals’ • Throw ‘by-catch’ back into the sea, by which time they are already dead • Causes problems for the environment

13. How can we manage our seas for the future? A look at fishing Is selective fishing gear the answer? • Big mesh sizes in nets help young fish escape so they can become big enough to reproduce • Some nets have escape panels to avoid catching big animals like dolphins e.g. dolphin friendly tuna • PROBLEM: Fishermen say they cannot catch enough fish with these forms of fishing gear to earn a living Large mesh sizes Escape panels

14. Fishing grounds No take zone ‘Spill-over’ of fish How can we manage our seas for the future? A look at fishing Are marine protected areas the answer? • Cuts an area off from fishing called a ‘no-take zone’ • Allows fish to become old enough to reproduce and excess fish ‘spill-over’ into fishing grounds • Protects habitat from destructive fishing too e.g. trawling • PROBLEM: Mixed success

15. How can we manage our seas for the future? A look at fishing Is aquaculture the answer? • Farming of fish to reduce the need to take ‘wild’ fish from the sea. • PROBLEMS: Fish farm wastes very polluting • Fish feed still relies on fish from the natural environment e.g. sand eels • Farmed fish have a much higher risk of getting diseases • Fishermen argue that aquaculture is replacing their jobs Fish farms in the Shetland Islands, Scotland

16. How can we manage our seas for the future? Probably a combination of all of these! • We have just dealt with fisheries • There are social, environmental and economic problems with managing human impact on the seas

17. How can we manage our seas for the future? So what steps would you take? • Fish species which are in higher abundance? Would people eat them and is that just delaying the problem? • Stop fishing completely? – how realistic is this? • Do we really need to eat fish? – thing about peoples diets and customs in other parts of the world • What could you do to help the situation? – The future of our seas is in your hands!

18. Take home messages • That food webs and more accurate at illustrating the feeding relationships in a community because: • An organism may be prey/predator of more than one other organism • We can see how nutrients are recycled in the food web • Ecologists can better predict the effects of removing, or reducing the abundance of, one or more organisms in the community • That human activities have an impact on food web structure in the marine environment, which can potentially result in catastrophic consequences for entire ecosystems • That we need to manage human impact on the marine environment with a view to promoting sustainable development of our seas