The unintended consequences of simplifying the sea: making the case for complexity

So here’s the old news….fish targeted by fisheries have been in decline for some time.  Removal or reduction of populations can alter ecological interactions, meaning that other species may become more abundant (or less) in their place.  This is typically done through something called competitive release (the species you compete with are gone, so there is more of a given resource for you) or trophic cascades (as one predator species is removed, its prey becomes more abundant because nothing is eating it.  Of course that means that there is more of those species to nibble away at whatever they eat, causing a population decline in that prey species).

Here’s the new..Prawns are really important to UK fisheries….about £110 million per year important, making them the move valuable of the UK fisheries.

Leigh Howarth and colleagues at the University of York, UK argue that this multi-million pound industry only came about because of overexploitation of other marine species – and that industry is not built on solid grounds.

It seems that the paper has some backing from the industry too, with the Sustainable Inshore Fisheries Trust – a Scottish based charity – supporting the findings.

For those with access to the journal ‘Fish and Fisheries’ you can see the original paper here

If you don’t have journal access, you can read the press release which gives an overview of the paper.

Image: The ecological effects of intensive fishing. From left to right, fishing effort increases over time. As a result, large predatory fish become depleted and fishers are forced to target new species.  Image made available with the press release.

Social-ecological vulnerability of coral reef fisheries to climatic shocks

Just as climate change is altering reef-associated species behaviour, ecology , and community structure below the water, so it too is impacting those on land.  That includes people.  The FAO have taken a look at the socio-ecological impacts of climate climate change and ocean acidification on a human community in Kenya that utilizes reefs for their livelihoods and survival.

Here’s the blurb from the FAO:

“This [FAO] circular examines the vulnerability of coral reef social-ecological communities to one effect of climate change, coral bleaching. The objective was to develop and test in Kenya a community-level vulnerability assessment approach that incorporated both ecological and socio-economic dimensions of vulnerability in order to target and guide interventions to reduce vulnerability.

In addition to a range of direct threats such as siltation, overfishing and coral disease, coral reefs are now threatened by climate change. Climate impacts on coral reefs and associated fisheries include:
increasing seawater temperatures;

  • changes in water chemistry (acidification);
  • changes in seasonality;
  • increased severity and frequency of storms, which affect coral reef ecosystems as well as fisheries activities and infrastructure.

Coral bleaching and associated coral mortality as a result of high seawater temperatures is one of the most striking impacts of climate change that has been observed to date. As warming trends continue, the frequency and severity of bleaching episodes are predicted to increase with potentially fundamental impacts on the world’s coral reefs and on the fisheries and livelihoods that depend on them.

The analysis presented in this circular combined ecological vulnerability (social exposure), social sensitivity and social adaptive capacity into an index of social-ecological vulnerability to coral bleaching. All three components of vulnerability varied across the sites and contributed to the variation in social-ecological vulnerability. Comparison over time showed that adaptive capacity and sensitivity indices increased from 2008 until 2012 owing to increases in community infrastructure and availability of credit. Disaggregated analysis of how adaptive capacity and sensitivity varied between different segments of society identified the young, migrants and those who do not participate in decision-making as having both higher sensitivity and lower adaptive capacity and, hence, as being the most vulnerable to changes in the productivity of reef fisheries.”

The full report is open access.

Image: Toka Panda spear fishes for reef fish, Santupaele village, Western Province, Solomon Islands. Taken by Filip Milovac.  WorldFish/Flickr (CC BY-NC-ND 2.0)

Rise in industrial fishing correlated decline in size of petrel prey

It makes sense that industrialized fishing has altered marine food webs, but understanding exactly how it has can be challenging.  We don’t have that much in the way of background data on what – and how much – was swimming about the oceans before industrial fishing began – let alone a full picture of what is there now.  We also lack a full record of who was fishing what, when, where and how much they were taking.

For Dr Anne Wiley and colleagues at Michigan State University…challenge accepted!  A little out of the box thinking saw the team delving into the nitrogen-15 and nitrogen-14 isotopes in the bones of the endangered Hawaiian petrels.  Using stable isotopes, scientists can figure out exactly where in the food chain these birds have been feeding.  And because the isotopes remain in the bones the team were able to compare the diet of modern-day petrels with petrels that were flying around hundreds and even thousands of years ago.

Pretty neat huh.

What they found was that the petrels used to feed on bigger species quite high up in the food chain.  So what happened when industrial fishing began?  With this new and efficient predator, the petrels switched to catching smaller prey from further down the food chain.

For those with access to the journal PNAS, the original paper can be found here

Image: Lead author Anne Wiley with a newly discovered, ancient Hawaiian petrel skull from Puu Naio Cave, Maui. After radiocarbon dating, the team learned that this bird died around 1400 A.D.  Credit Andreanna Welch, kindly made available for release with the paper

The Law That’s Saving American Fisheries

The 1976 Magnuson Stevens Fishery Conservation Act was arguably a groundbreaking piece of legislation that prevented widespread collapse of the US fishing industry.  It is perhaps most famous for establishing the 200 mile EEZ around the US, but it also forms the backbone of sustainable fisheries initiatives.  Of course its not 100% successful, and many lessons have been learned, and are still to be learned.

Its now time for the Act to be reauthorized, so Pew have produced a report “The Law That’s Saving American Fisheries: The Magnuson-Stevens Fishery Conservation and Management Act”, explaining the importance of this evolving legislation to US fisheries management.

You can read their introduction to the report here, as well as download a copy.  Its not too long-winded (about 44 pages, including some infographics and photos) so why not have a flick through next time your having a a sip of your tipple of choice

Image: The Fishermen’s memorial in Gloucester, Mass.  Credit: NOAA Photo Library

Study highlights under-appreciated benefit of oyster restoration

Chesapeake Bay has a long history of fishing – and overfishing.  Oysters were a commercially important species even as far back as the 14th century, and centuries of overexploitation have left the Chesapeake devoid of the rich oyster reefs that once existed there, and consequently altered the ecosystem making conditions difficult for many other species – including commercially harvested ones.  This is not just because they are part of the food chain, but because they are ecosystem engineers.  Not only do oyster reefs provide a hard substrate for many other species to live on and around, but they are tenacious filter feeders, cleaning up the water of the bay.  It makes sense to instigate oyster restoration projects – not just as a means of providing a food source but also to reverse the degradation of the ecosystem.  Unfortunately it is not always that simple, especially where conditions have degraded so dramatically that oysters may simply no longer be able to thrive in areas they once inhabited.

A recent study by Professor Waldbusser and colleagues suggests that one reason for degradation – ocean acidification – can also be buffered by oyster reefs.  The idea is simple.  Acidic waters mean oyster shells ‘dissolve’ and as they do so, release an alkaline salt that buffers the acidity levels.  The problem today is that there aren’t that many dead oyster shells left in the Chesapeake because when we harvest them, most of the shells aren’t returned to the bay, and the buffer is heavily reduced.

For those with access to the journal ‘Ecology’, the original paper can be found here

Who owns the fish in the sea?

The UK High Court is being asked to make a judgement over the question of who owns the fish in the sea.

Its been a long running battle.  Briefly, the UK Government want to reallocate unused quota from ‘big businesses’ to small scale fishers.  You can see why this is a contentious issue.  ‘Big business’ wants to keep the quota because they might need it in the future, but the smaller-scale fishers feel that their businesses might be more viable if they were allocated a larger share of the allowable catch.

The news story from the BBC is here.

If you want to read more about the small-fisher perspective, check out what the New Under Ten Fishermens Association have to say here.

An official statement from the IK Association of Fish Producer Organisations (representing ‘big business interests’) can be seen here.

Image:  Fishing boats in Lyme Regis, England.  Credit Paul Lucas/Flickr (CC BY 2.0)

Marine Protection Goals Are on Target, But Still Not Enough

Mark Spalding and colleagues have recently released a study assessing the state of the world’s marine protected areas.  Although uptake in these areas has increased over the last decade, and we might actually be on track for reaching 10% ocean protection by 2020 (this was originally 2012…we missed that by a long way), the authors note all is not quite what it seems.  Paper highlights (taken from this paper review, plus an addition from me) are as follows:

– A small number of large MPAs are responsible for much of the global growth: The 20 largest MPAs account for 60% of the entire global MPA coverage, with an increasing trend to cover remote and off shore areas.

– By contrast, in terms of numbers, the majority of MPAs are small and are found in coastal and near-shore waters. Even with these there is a focus on sparsely populated areas. The average MPA is small and most are not effectively managed.

– MPA coverage is highly variable — while 28 countries have now exceeded 10% coverage of their waters, some 111 are still at less than 1%.

– MPA coverage does not equal protection: MPAs can be ineffective due to failures in management or design. A simple numbers-based approach ignores the challenges of effectively designing MPAs to provide the most benefit for marine biodiversity and for people.

– Designing MPAs for people — is crucial to get right. For the past decade or more, the conservation community has touted MPAs as tools to help reduce poverty and improve human wellbeing for local communities. While some are doing that quite effectively, they are rare. This study was the first to plot MPAs alongside coastal density, finding that most MPAs are in areas far away from people, in remote ecosystems that typically have high levels of biodiversity and few conflicting demands for ocean space.

– MPA success at reaching biodiversity targets and rebuilding of associated ecosystem serves is heavily dependent on how we use the surrounding waters.  MPAs are not islands isolated from the rest of the ocean.

The original paper is open access – meaning free for all tor read.

Image: Sign marking the no-take marine sanctuary on Apo Island, Philippines. Credit Rebecca Weeks/Marine Photobank

National Federation of Fishermen’s Organisations under scrutiny

There is a powerful trade body that represents our fishermen’s interests in Westminster and Brussels – the National Federation of Fishermen’s Organisations. It speaks for fishing interests large and small and puts their case to those who make the laws. Or so it claims. Yet Greenpeace has found that this body has been opposing changes to fishing policies, such as there alignment of fishing quota, which would help precisely the kind of small scale fishermen they claim to represent.

An in-depth investigation by Greenpeace into the reality behind the NFFO has revealed that all may not be as it seems.  Here are some of the highlights:

Continue reading National Federation of Fishermen’s Organisations under scrutiny

US Magnuson-Stevens Fishery Conservation & Management Act has prompted rebuilding of a number of fish stocks

Well its not often we hear some good news from the marine environment, especially when looking at fisheries – but here’s some!

According to a report by the National Resource Defence Council – an environmental action group – the US Magnuson-Stevens Fishery Conservation and Management Act has prompted rebuilding of a number of fish stocks…

•28 of 44 fish stocks — or 64 percent — have been designated rebuilt or met their rebuilding targets, or have made significant rebuilding progress.
•21 stocks have been designated rebuilt or met rebuilding targets (and have not been designated as again approaching an overfished condition).
•Seven stocks have made significant rebuilding progress, defined as achieving at least 50 percent of the rebuilding target and a 25 percent increase in abundance since the start of its rebuilding plan.
•Estimated average annual 2008-2010 gross commercial revenues from these 28 stocks totaled almost $585 million — 92 percent higher (54 percent when adjusted for inflation) than revenues at the start of rebuilding.
•Eight stocks have made limited rebuilding progress (either achieving 50 percent of their target or a 25 percent increase in abundance) and eight stocks have shown a lack of rebuilding progress (achieving neither of these thresholds).
•Areas of concern include (a) gaps in the application of the rebuilding requirements, such as with respect to stocks that are not federally managed, are of “unknown” population status, or are internationally managed; (b) regions, such as New England, the South Atlantic, and the Gulf of Mexico, with significant proportions of stocks showing a lack of rebuilding progress; and (c) continued overfishing during rebuilding plans.

Full report available here

Image: School of unknown fish in Indonesia.  Credit Tom Weilenmann/Flickr (CC BY-NC-ND 2.0)

Overfishing linked to increasing numbers of sponge

Check out the size of that sponge!

Seriously, its a sponge, aptly named the “Giant barrel”.  But as awesome as this sponge is to look at, its not so awesome if your a coral.  Research by Joe Pawlik and colleagues released this week suggests that overfishing of fish that love to tuck in to a bit of sponge means sponges are taking over on some coral reefs.  There’s a nice overview of the paper or alternatively if you fancy reading the paper yourself you can – it’s open access!

Image: The giant barrel sponge taken by the paper author Joe Pawlik, UNC

"I don’t think that I can change the world, I just wanna punch it up a little" ~ Joss Whedon

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