At least 7.3m tons of fish (usually dead or dying) are thought to be discarded each year from marine fisheries around the world. But these estimates come mostly from observations of large-scale industrial fisheries. Limited attention has been paid to small-scale fisheries, which are assumed to have low discard rates – some
Britain’s seagrass is a refuge for numerous species of fish, stabilises sandy beaches, and helps to lock away the carbon which humans produce. The meadows that surround the country’s coast have been called the “canaries of the sea”, due to their sensitivity to a changing environment. And like a canary
Fishing in seagrass occurs around the globe; if there is seagrass (and people) there is fishing. Still, the nature and extent of fisheries in seagrass is poorly understood. It is a prerequisite for natural resource management to understand resource exploitation, therefore we decided to investigate this further. Seagrasses are plants that
At least 7.3m tons of fish (usually dead or dying) are thought to be discarded each year from marine fisheries around the world. But these estimates come mostly from observations of large-scale industrial fisheries. Limited attention has been paid to small-scale fisheries, which are assumed to have low discard rates – some estimate as little as 3.7% total catch, compared to more than 60% for some large-scale shrimp trawlers. Small-scale or artisanal fisheries – for which there is no universal definition – are generally considered more sustainable than their large-scale industrial counterparts, but there is increasing evidence that shows this is not always the case. They employ more than 99% of the world’s 51m fishers and likely account for more than half of the total global fisheries catches. A Sri Lankan fisherman. One of the biggest problems for both large and small-scale fisheries around the globe is bycatch – fish and other marine organisms caught when the fishers are targeting something else. Powerful images of turtles and dolphins caught in fishing gear have caught the sympathy of the general public, but unintentional landings of fish aren’t as evocative. The truth is, however, that fish bycatch is a big issue. Progress is being made in Europe within large-scale fisheries thanks to campaigns such as the Fish Fight. But small-scale fisheries – though there is increasing recognition outside that they are “too big to ignore” – are only just beginning to recognise the fish bycatch and discard problem. Catch and bycatch. Our newly published research has found that artisanal fisheries in Sri Lanka are throwing away more marine species than they keep. For every fishing trip in one of Sri Lanka’s largest lagoons, Puttalam Lagoon, fishermen could be throwing away more than 50 fish. What’s more, of the 62 species recorded in the survey, more than 80% were routinely discarded. The reasons for this practice are unclear but sometimes it is because the individual fish are too small – or they are species without a high market value. We found that fishers targeting shrimp in particular caught more non-target species and had higher discards than those targeting fish. This is particularly worrying at a time when Sri Lankan shrimp exports are increasing, after the EU granted the country improved access to its market. Fishers in Puttalam Lagoon discard non-target catch onshore. Potentially 90% of the world’s fish stocks are threatened by over-fishing – when more fish are caught than the population can replace. And the “tell-tale” signs of over-fishing are now being observed in Sri Lanka and across other research sites in the Indo-Pacific region. Fishers in these locations have told us and other researchers that they are catching much less fish than they were five years ago. But this is not just an ecological issue, it is a social one too. In this era of increasing food insecurity, our findings highlight a serious concern for Sri Lanka. This unwanted seafood could be used to provide protein for the poorest in society. Instead, we found that fish with high nutritional value is being eaten by feral dogs and birds. Unwanted fish end up as quick and easy meals for animals. Billions of people worldwide rely daily on fish for protein, while 50m people also rely on catching fish for work. But, if the levels of bycatch and discard continue, the livelihoods and food security of the people that depend on these fisheries will be under threat. If the problem is not managed, there won’t be any fish left in the waters. There is one ray of hope for Sri Lanka, however. There are some small-scale fishery cooperatives which maximise long-term community benefits by dealing with the threats of fisheries mismanagement, livelihood insecurity and poverty. Communities with successful and inclusive cooperatives are better off than those without. Cooperatives have the potential to empower small-scale fishers against environmental and socioeconomic shocks, but the problem in Puttalam Lagoon is that these cooperatives are not operating across all levels of society. Fishing cooperatives do exist, but there could be more. If the bycatch and discards issue is going to be solved over the long-term, we need to look at combining sustainable management practices with community schemes to reduce unnecessary seafood waste all over the world. Together the millions of small-scale fishers all over the world have an immense amount of power, they just need to realise it. This article was originally published on The Conversation. Read the original article.
Britain’s seagrass is a refuge for numerous species of fish, stabilises sandy beaches, and helps to lock away the carbon which humans produce. The meadows that surround the country’s coast have been called the “canaries of the sea”, due to their sensitivity to a changing environment. And like a canary in a coal mine, their health can be used as an indicator of the condition of coastal areas. We know that the seagrass meadows surrounding the UK are in a perilous state of decline, and our recently published research has now uncovered one of the biggest causes. Our study suggests that a major driver of seagrass decline is nutrient pollution from sewage and livestock waste. Though a new finding, it sadly comes as no surprise, given that about 40% of rivers in England and Wales are polluted with sewage. This nutrient pollution puts the long term viability of seagrass meadows in doubt. Over-enrichment results in the suffocation of seagrass. The nutrients cause microscopic algae – called epiphytes – to smother the seagrass leaves, decreasing their ability to capture light, ultimately killing them, and destroying the habitat for fish and other marine animals. Â The seagrass, Zostera marina, covered in epiphytes. In addition to this environmental impact, we found that several areas, including the Thames waterway seagrass, and a meadow in Studland Bay, Dorset – which are popular with swimmers and boaters – were considerably enriched in nutrients from sewage, livestock effluent and/or human waste. Despite this, neither location, nor any other we identified with the same problem, were classed as unsuitable for swimmers. Outdated treatment Clearly, we have a massive problem at hand – but water companies, farmers and the government have not done and are still not doing enough to prevent it. Though efforts have been made to develop a British marine protected area network, and EU legislation has improved water quality in the last few decades, we have found these initiatives to be insufficient. Ten of the 11 sites we studied were in areas with designated EU protection, but most of these seagrass meadows were still polluted with nutrients derived from urban sewage and livestock waste. So how has this happened? Analysis of the seagrass tissues points to constant sewage exposure. Old and outdated water treatment facilities are one of the likely culprits, resulting in discharges of untreated sewage during times of heavy rainfall. These are legal, but evidently the capacity of these facilities is insufficient to handle the country’s needs, and waterways are suffering because of it. There is also the problem of livestock waste. Farming is now one of the UK’s leading causes of water pollution, and inefficiencies in storage and disposal of slurry mean that it ends up in rivers and coastal waters. Local and national Evidently, in addition to national and international initiatives, we need to start quickly identifying and understanding all local threats to seagrass. Especially if we are going to harmonise conservation goals with sustainable economic development. Only by finding out specifically where the nutrients affecting seagrass areas have come from can we really start to think about a targeted solution for each meadow. Unfortunately, to date, the conservation of specific seagrass meadows is rarely based on the explicit consideration of local threats and drivers. Instead, projects focus on conserving seagrass as part of a broader plan, incorporating other specific habitats or species. While this may be effective at dealing with problems such as fisheries impacts, and is certainly a step forward for the marine environment, it doesn’t deal with the persistent and chronic problem of pollution – which can go largely unnoticed. Poor water quality isn’t just a problem for seagrass in the British Isles, it’s a global concern. But if we want to solve it, we must look beyond “protecting” seagrasses with legislation, and challenge the way we think about marine protection overall. Serious infrastructure changes and better management of river catchments – for example, restoration of riverbanks – are vital if we are going to develop long term waste water management plans that span both land and sea. You can read the study, Tracking Nitrogen Source Using δ15N Reveals Human and Agricultural Drivers of Seagrass Degradation across the British Isles, here. This article was originally published on The Conversation. Read the original article.
Fishing in seagrass occurs around the globe; if there is seagrass (and people) there is fishing. Still, the nature and extent of fisheries in seagrass is poorly understood. It is a prerequisite for natural resource management to understand resource exploitation, therefore we decided to investigate this further. Seagrasses are plants that grow in the shallow ocean. The seagrass attracts many different types of animals, to live, forage, or seek shelter. These animals are collected by humans for subsistence (food), commercial and recreational purposes. Across the globe the reasons for fishing differs, it is more common to fish for recreational purposes in countries where the economic situation is better, while in countries with more challenged economies fishing for subsistence is very important. Interestingly, because seagrasses grow in nearshore environments, almost all types of fishing gears are used. Close to shore in many areas of the world the seagrass gets exposed during spring low tides making it possible to walk in the seagrass meadows. Many people take advantage of the low tide and walk across the seagrass meadows collecting invertebrates, such as mussels and sea cucumbers, often with bare hand or simple fishing gear like sticks. This type of fishery is commonly referred to as gleaning or invertebrate harvesting and is conducted by men, women and children. Gleaning is especially common and important for people with limited resources. Static nets are also used in the intertidal zone, the area where the tides raise and fall, catching fish when the tides come in. It is very common to use hook and line and fishing nets in seagrass. Unfortunately, very destructive fishing gears such as bottom trawls, poison, dynamite, and rakes are also occasionally used. Women and children walk across seagrass meadows at low tide in indonesia collecting resources that they can eat (Photo: Benjamin Jones) On a global scale, anything found in the seagrass that can be eaten, sold, used as bait or sold as a curio is targeted. Globally, the most commonly targeted invertebrates in seagrass appear to be crabs and bivalves (mussels). The most commonly exploited finfish from seagrass are mullet, herring, and snapper. The target species varies greatly across the globe, for example in areas with high biodiversity (many types of species), the number of target species is often higher than in areas with low biodiversity. This pattern often corresponds with colder water fewer species, warmer water more species. Species groups that are least commonly targeted are sea cucumbers, small fish for drying, aquarium trade species, seahorses, and sharks. People access the seagrass fishing grounds by walking, swimming, snorkelling, free diving, use of canoes, scuba diving, use of sailboats and motorboats. Crabs and bivalves appear to be the most commonly targeted invertebrates across the globe (Photo: Benjamin Jones) Seagrass meadows receive limited management attention compared to other nearshore marine habitats. Fisheries management does not yet target seagrass. But seagrass fisheries are diverse and important to people the world over. We, authors, hope that these findings, now systematically and scientifically investigated, will highlight the importance of seagrass for fisheries around the globe. Source: ‘Global significance of seagrass fishery activity’ by Lina Mtwana Nordlund, Richard K.F. Unsworth, Martin Gullström, Leanne C. Cullen-Unsworth. Published in Fish & Fisheries 2017. Arial footage of a nearshore environment with patchy seagrass, in the upper left corner there is a fishing boat and along the right edge there is a long fishing net deployed (blue in color), Tanzania. Drone pilot and photo LM Nordlund.
