The post Blue Planet 2 | Episode 7 | Our Blue Planet appeared first on Exploring our Oceans .
]]>This was by far the most important episode of the series. I am sure that many viewers were troubled by the scale of some of the issues touched upon in the programme; as biological scientists, we live in this state of concern perpetually, both professionally and personally. I tend to see a disconnect amongst the public, that the world we inhabit in our cities and towns are independent of ecological relationships that existed before humans, and now around humans, particularly when it comes to ocean life. In reality, this is not the case. Humans inhabit a unique ecological niche in the history of life on Earth, in that we are the only superpredators ever to regularly predate on the adult forms of other apex predators, in every environment on Earth. There has been talk of considering the era of humans a new geological epoch, defined by extinction, climate change and a stratigraphic layer of plastic for the geologists of the future. Accepting these problems are happening, let alone confronting them, can be depressing. I can’t speak for everyone, but taking a step back, as a scientist, and thinking of these as an interesting series of problems to be understood, is at least how I have decided apply myself to it. Entire books and feature length films have been made on each of the ecological issues in this final episode, so I will only focus on overfishing.
Unlike life on land, which has been drastically modified by humans for as long as we have existed, ocean life has only become heavily exploited more recently (although setting a baseline can be contentious). We have thought of life in the ocean as this resource which will never be exhausted. Marine biologists have learned in the last few decades that this is not the case. A high profile example is the cod fishery off of Newfoundland, Canada, which was a plentiful food source for 500 years, thought to be the most productive fishery in the world. As fishing technologies improved, more fish could be caught more efficiently and in less time. After regulation failed to curb declines, the cod population completely collapsed in the early 1990s, and has still not recovered. With such a large amount of large predatory cod absent from the ecosystem, a trophic cascade occurred, where smaller fish severely declined and zooplankton, seals and crabs exploded in population. Meanwhile, cod in this area rarely reach adulthood here anymore. Managing the fishery like a resource by considering only population size, and not complex life histories and other ecological relationships, lead to this economic and biological catastrophe.
Modern fisheries science that we learn about at Southampton tries to account for this by having a ‘minimum landing size’, the idea being that to bring a fish to shore it must be large enough to have reproduced a few times to ensure the longevity of the population. Many fish become more reproductively fertile, producing more babies, as they grow, a good evolutionary strategy, as in a humanless world you are less likely to be eaten if you are bigger. Like any kind of strong selection pressure, predation pressure from fishing drives evolution. An example of the undesired result of this form of management is that cod now reach sexual maturity at a smaller size and a younger age. It is now more of an advantage for them to reproduce smaller and younger than it is to get larger, because they are small enough to fit through the holes in the legal requirement for fishing nets. Millions of years of evolution have been drastically modified by fishing pressure in a matter of decades. As we saw in episode 1, some fish change sex as they grow, meaning that fishing can skew the sex ratios to the first sex, with further implications for reproduction. We learn in our course that studying these life cycles is the best way of informing fisheries management, but fisheries is big business (worth $246 billion worldwide) and recommendations from the scientific community are sometimes opposed or lobbied against, affecting its influence on legislation. This means as well as facing challenges with ensuring scientific methods are robust, replication is adequate and your baseline is informative, whether your recommendations are taken seriously can be dependent on outside factors. There are no easy answers to these problems, but having the backing of the public does put pressure on the powers that be.
The wild caught fish that we eat is wildlife, and they shouldn’t be glossed over with the same brush as I sometimes see. Different commercially available fish are as ecologically different to each other as songbirds are to tigers. Tunas for example are apex predators, and although eating tigers, sharks and lions is unusual in the Western world, tuna consumption is extremely widespread. Imagine feeding tiger meat to your cat. Some bluefin tuna can grow to the size of a small car and have endangered or critically endagnered IUCN conservation status (on the same level as the Bengal tiger and black rhinoceros) and yet are still available at most sushi restaurants. There is always talk of ‘dolphin friendly’ tuna, but tuna themselves require urgent conservation as well. Despite improved scientific method, commercial fish species continue to decline worldwide, and faster than estimated.
I am sometimes asked: as a concerned citizen, what can I do in the face of these problems? Honestly, there is no easy answer. Some of the things I would recommend have been suggested a thousand times before, but I will make a few suggestions anyway:
Despite grave threats facing the ocean, life is remarkably resilient, and where beneficial alternatives are provided, there are success stories. Despite resistance from the fishing industry, no-take zones like those in New Zealand have proved highly successful at restoring fully mature fish and species not seen in decades, protecting biodiversity and then being available for fishing as well. For us, the four-year Blue Belt plan aims to protect 4 million square kilometres of marine habitat, an area larger than India, across 7 UK Overseas Territories. Ultimately, getting business to prioritise conservation, and large scale international cooperation on legislation are ultimate goals, but these large scale changes always begin with small groups of scientist, campaigners and passionate citizens. Some of this has come from our university. If you can convince your place of work to waste less food or use less plastic, then why not do it? You can also go here to check if your local MP is on board with the Blue Belt plan, and contact them to tell them to vote in its favour. As a country with the fifth largest area of marine habitat in its jurisdiction, having this go through UK parliament would be globally significant.
The public engagement from this new Blue Planet series has been extremely heartening. It was so popular in China that it slowed down the internet there, and is the third most watched series of the last five years. I look forward to seeing what people inspired by the series will do in the future.
Feel free to ask me any further questions on Twitter @kieranyes.
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]]>The post Blue Planet 2 | Episode 6 | Coasts appeared first on Exploring our Oceans .
]]>We have a tendency to take our coastlines for granted. It is by far the most accessible and relatable marine habitat, with thousands flocking there every day for their primary source of food, watersports, or just to relax. The UN estimates 40% of the world’s population live in coastal areas. They provide the most extensive economic and social benefits of any natural habitat, encompassing 77% of the services provided to us by all ecosystems. It is where most of us began our love for the sea. In the UK, you are never more than 70 miles away from it. Yet it is easy to forget it is a place of extremes, and as important as any other marine habitat.
Coastal species have to endure excruciating changes in their environment twice a day. Marine animals can be categorised based on their preferences and adaptability to two primary conditions: temperature and salinity (‘saltiness’). A change in salt might be nothing to one of us as we are osmoregulators (we regulate our internal environment) – for an osmoconformer, like a sea cucumber or starfish, this can be devastating. Too little salt, and your internal water diffuses out, and too much, and outside water will pass in until your cells burst. In the ocean, these conditions remain relatively stable – you can assume that they are unlikely to change dramatically in the next few metres, or few hours. However, if you live in the intertidal zone, you are likely to be bombarded with really hot temperatures at low tide, dramatic changes in salinity if you live in an estuary or at a river mouth, and running out of oxygen if you are caught in a rockpool. To make matters worse, the coast itself is constantly shifting, as shown in the programme. You have to be very hardy and resilient to live here.
Coastal management is a huge challenge anywhere in the world – there is always a trade off between using the coastline for economic and recreational ventures, but not at the sacrifice of the coast’s ecology and longevity. Although only covering 20% of the Earth’s surface, 41% of the world’s population are coastal inhabitants. For example Guyana, a country larger than the UK, 90% of its population lives on a narrow coastal plane, and only a narrow sea wall protects its inhabitants from the ocean. 21 of the world’s 33 megacities are found on the coast, including Tokyo, Lagos, New York and Buenos Aires. With a globally increasing population, how do we ensure coastlines are sustainably developed and not overxploited?
I have noticed that the UK’s coastlines are a severely underrated habitat among many wildlife enthusiasts. Since the establishment of Lundy Island as the first MCZ (Marine Conservation Zone) in January 2010, a total of 50 sites now make up an area the same size as Wales. These are designated to protect rare and threatened species, and also the wide diversity of life found here. We were lucky enough to conduct some camera drop surveys of the maerl beds of the Fal Special Area of Conservation – a red calcareous algae, superficially similar to corals – of which the UK has in several locations. Maerl can be up to 8000 years old, and provide habitat for rare species like Couch’s goby, much like coral reefs do in the tropics. Additionally mudflats, estuaries and sandbanks are not the most glamorous marine habitats but have still been highlighted for conservation as part of global efforts to conserve biodiversity. Just as an example to the importance of this Blue Belt initiative, seagulls are a red list species in the UK due to their overall declines across the country due to habitat loss. This will come as a surprise to many. They are widely considered pests as they have been increasing in urban areas, partly because of abundant food, and partly because they have nowhere else to go.
Appreciating and conserving the marine environment does not just encompass tropical coral reefs, the great whales of the open ocean and the polar ice caps that many of us will only ever admire through a screen. Declines in biodiversity are all-encompassing and are essential for the future of habitats, and ultimately, our own wellbeing. We in the UK are just as responsible for protecting our marine species as any other country, and you don’t have to fly to the tropics to be close to the Blue Planet.
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]]>The post Blue Planet 2 | Episode 5 | Green Seas appeared first on Exploring our Oceans .
]]>There is plenty about this episode to talk about. Phytoplankton – an umbrella term for a menagerie of different photosynthesizing organisms – prop up all other life in the ocean and provide 50% of oxygen for the entire Earth. Despite only covering 0.1% of the Earth’s surface, ‘blue forests’ (seagrass meadows, kelp forests, salt marshes and mangroves) capture about a third of carbon dioxide produced since the Industrial Revolution. Stacey Felgate’s excellent post talked a great deal about ‘blue carbon’ and wetland decline’s consequences for global climate change. Elin correctly predicted sea otter trophic cascades making an appearance – there are fascinating other examples of this from Yellowstone Park to the extinction of giant Ice Age animals. The scenes showing octopus and cephalopod ingenuity could warrant several extensive essays on some of their incredible capabilities, and equally some of the challenges with defining ‘intelligence’ in order to study animal cognition.
I’ll talk specifically about mangrove forests, a tropical coastal habitat characterised by marine adapted trees. Mangroves are an extremely interesting, and extreme, habitat. They have to endure the dramatic changes in salinity and temperature that characterise the intertidal zone. To cope with living in salty water, the mangrove trees have had to evolve to excrete salt from their leaves or by depositing it in roots or bark. These trees are also considered ‘viviparous’ – meaning they give birth to live young (it sounds strange, but this is the correct term!) – as young trees fall straight out of the adult tree and stick straight into the sand or mud like daggers. These ‘baby trees’ are called propagules, and in other cases they may float for weeks across the ocean. Mangroves only cover 0.1% of the Earth’s surface, but account for around 14% of total terrestrial carbon input to the ocean. They provide a link between the ocean and the land, which an extensive menagerie of different species utilise and have adapted to.
As well as being home to many species of juvenile fish, they also provide shelter and resources for dolphins, manatees and dugongs, hundreds of species of birds, and even monkeys. Borneo’s distinguished proboscis monkey is a mangrove specialist. Biodiversity value aside, charismatic animals attract tourists and fish nurseries promote the availability of fish for consumption, particularly important when the majority of people around them rely on fish for their primary source of protein. The tree roots also stabilise the environment, making it easier for other species to live in. The role of mangroves in storm and tsunami protection has provided more incentives to protect them, particularly as extreme storms are becoming more frequent with climate change.
The simple fact is, if you are eating cheap shrimp today, it almost certainly comes from a turbid, pesticide-and-antibiotic filled, virus-ridden pond in the tropical clines of one of the world’s poorest countries
But not all is hopeless – mangrove restoration projects exist all over the world, and are reasonably successful. More robust protection is needed worldwide, and this starts with awareness, which Blue Planet II is doing superbly, and will continue to into the future. And, of course, think twice next time you buy cheap shrimp.
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