Dangerous cargo: the accidental spread of alien organisms via commercial shipping

It's often said that whichever culture and environment we grow up in is the one we consider as the norm. Whilst my great-grandparents were born before the invention of heavier-than-air flying machines, I've booked numerous long-haul flights without considering much beyond their monetary and environmental cost. Yet this familiarity with our fast and efficient global transportation network masks an unpleasant side effect: it is second only to habitat loss when it comes to endangering biodiversity.

Although many environmental campaigns focus on fossil fuels, deforestation and unsustainable agricultural practices, the (mostly inadvertent) transportation of alien plants, animals and fungi from one region to another has quietly but catastrophically reduced biodiversity in many areas of the planet.

The earliest example I recall learning about was Stephen Jay Gould's heart-felt description of the extinction of French Polynesia's partulid tree snails at the hands of introduced carnivorous snails intended to control edible snail species (which were also deliberately introduced). While the nineteenth and early twentieth centuries saw large numbers of species intentionally established in areas far from their natural territories, the past half century has seen an acceleration in equally disastrous accidental introductions as a by-product of international trade.

A potential starting point for invasion ecology as a discipline in its own right was Oxford professor Charles Elton's 1958 publication The Ecology of Invasions by Animals and Plants. The International Union for Conservation of Nature's Red List of Threatened Species followed six years later. Clearly, the negative effects of our activities were starting to become known. But has enough been done to publicise it in the intervening decades?

The Red list is the most accurate data source for regional biodiversity and the population health of all organisms known to science; yet few non-specialists seem even aware of its existence. Indeed, several decades passed after the list's creation before invasive biology became an important subject in professional ecology. Over the past thirty years the topic has seen a ten-fold increase in publications and citations - a sign of recognition if ever there was one - although mainstream media appears barely aware of its existence.

The IUCN's Invasive Species Specialist Group aids governments and organisations in planning the monitoring, containment, and where possible, destruction of invasive species. It runs the publicly-available Global Invasive Species Database, but its online presence appears to be poorly funded, or at least coordinated. Rather than a central hub there is a plethora of websites featuring varying degrees of professionalism and some distinctly out-of-date content. Perhaps clients are given direct instructions, but as a member of the public I found the ISSG sites bewildering in their variety.

Needless to say, when it does come to taking action, it can be assumed that economic imperatives such as agricultural pests take precedence over preservation of other endangered species. The only country I know of that is attempting a nation-wide eradication of most invasive animals (note: not plants and fungi) is New Zealand, with our Predator Free 2050 project. However, I'm uncertain how realistic it is. Even pre-Covid it appears to have lacked a solid funding source and now - with thirty years and counting until the deadline - there's even less chance of a comprehensive removal of numerous pest species.

What the Predator Free 2050 plan doesn't include is the multitude of plants and animals that slip through the net, so to speak: the legion of species currently invading our offshore environment. It's one thing to actually see land-based plants and animals, but the ocean is largely unknown territory to most people. With over forty thousand cargo vessels moving around the globe every year there is plenty of opportunity for organisms, especially their larval forms, to be inadvertently spread to new territories via both hulls and ballast water. Whilst Killer Algae (a slight hint there in the common name for Caulerpa taxifolia) and the Chinese mitten crab aren't as well-known as Japanese knotweed and Common myna bird they are just two of the many dangerous invaders spreading ever further from their original territories.

It isn't just marine vessels that can carry such dangerous cargo: the immense amount of plastic waste in our oceans can serve as life rafts for the propagation of alien species, albeit at the whim of currents moving rather slower than diesel power. The problem of course is that the oceans are enormous and so the only time the issue becomes known about is when an invasive organism is spotted encroaching in coastal waters. Unfortunately, marine lifeforms can't be easily dealt with using the traps and poison that work on land-based entities; indeed, international regulations seem as much concerned with the dangers of anti-fouling systems as with the issues they prevent.

In 2011 the International Maritime Organization implemented guidelines to minimise vessel biofouling as it relates to the accidental incursions of invasive marine organisms. New Zealand was the first of several nations to execute their own national strategy that turned these guidelines into mandatory practice - and take them further. In addition, New Zealand's National Institute of Water and Atmospheric Research (NIWA) runs annual surveys, particularly around ports, but otherwise their funding appears inadequate to the immensity of the task. 

It's all very well keeping track of the ever-increasing list of resident invasive species around the nation's coastline, but little has been done to remove them. With about 150 types of alien organism now in residence around New Zealand's coast and the same again in occasional visitors, NIWA has been a partner in international competitions aimed at finding pest management solutions, at least for coastal ecosystems if not the deep ocean. Obvious solutions such as scrubbing hulls would just lead to direct contamination of ports, so some new thinking is clearly required.

Of course, the use of cargo ships is unlikely to reduce any time soon. Our global marine transport network is far from in decline and many nations lack the stringent precautions that New Zealand and Australia are now implementing. It has been estimated that cleaning hulls to prevent biofouling could reduce global marine fuel consumption by 10%, so perhaps this commercial benefit may win over those reluctant to spend heavily on prevention measures. But just as fishing vessels are still getting away with immense amounts of by-kill, merchant shipping in many areas of the world appears to be a law unto self.

Preserving regional marine biota is just as critical as land-based environmental protection. Allowing species to proliferate outside their normal range can only lead to deleterious changes - and when combined with our warming, increasingly acidic oceans, this does not bode well for all life on Earth, especially a hungry Homo sapiens. Just because we humans spend most of our time on land, we cannot afford to ignore the far larger ecosystems of the seas.

Troublesome trawling: how New Zealand's fishing industry hid the truth about by-kill

I recently signed a petition to reduce by-kill in New Zealand waters by installing cameras on all commercial fishing vessels. Forest and Bird and World Wildlife Fund New Zealand are jointly campaigning for this monitoring, as only a small percentage of boats as yet have cameras. The previous New Zealand government agreed to the wider introduction, but Fisheries Minister Stuart Nash is considering reversing this due to industry pressure. Considering that the current administration is a coalition involving the Green Party, this seems highly ironic. Is this yet another nail in the coffin of New Zealand's tourist brand as 100% Pure?

Despite requests from the fishing industry not to release it to the public, on-board footage shows the extent of the by-kill. High numbers of rare and endangered species have been drowned in nets, from seabirds such as wandering albatross and yellow-eyed penguins/hoiho, to cetaceans (there are thought to be only fifty or so Māui's dolphin/popoto left), seals and sea lions.

Many of the cameras already installed on New Zealand boats failed in the first three months due to inadequate waterproofing; when allied with the fact that the supplier of the technology was an integrated part of the seafood industry, there's more than a whiff of something fishy going on. Although official statistics are often considered to be of dubious quality, Occam's razor can be used to decipher the by-kill figures as they have been reported in the past decade. Only three percent of New Zealand's set net boats are officially monitored, yet they account for the vast majority of the recorded by-kill. Given a choice between sheer coincidence (i.e. only monitored vessels are catching large numbers of non-target species) and severe under-reporting from unmonitored boats, it is obvious that the latter hypothesis follows the law of parsimony.

Sadly, widespread deception by New Zealand's fishing industry isn't something new. A third-party report involving undercover operatives stated that between 1950 and 2010 up to 2.7 times the official tonnage of fish was actually being caught, peaking in 1990. All this comes from an industry that is laden with checks and measures, not to mention sustainability certificates. Killing marine mammals within the country's Exclusive Economic Zone isn't just a minor inconvenience: since 1978 it's been illegal, with severe fines and even prison sentences for those convicted. Small wonder then that the majority of by-kill has been undeclared.

What is equally sad is the lack of interest from the New Zealand public in resolving the problems. After all, over ninety percent of the population are not vegetarian, so we must assume the vast majority enjoy seafood in their diet. The rapid replacement of over-fished sharks with Humboldt squid in the Sea of Cortez off Mexico's Pacific coast shows how the removal of a key species can severely affect food webs. If New Zealanders are to continue to enjoy eating fish with their chips, the sea needs better protection.

Over the past decade, other nations have shown commitment to reducing by-kill and lessening waste. In 2010 the British celebrity chef Hugh Fearnley-Whittingstall launched the Fish Fight campaign to stop the discard of about half of the European Union's catch (due to it being either undersized or from non-quota species). Immense public support over the subsequent four years led to phased changes in the European Union's Common Fisheries Policy, proof that citizen action can make fundamental improvements.

Incidentally, it wasn't even a case of division along party lines; I was living in the UK at the time and wrote to my Labour Member of Parliament, who replied in a typically circumlocutory fashion that she would look into the matter! Even the then Conservative Prime Minister David Cameron agreed that EU policy needed a radical overhaul, a rare instance of cross-party sense and sensibility over pride and prejudice.

So what solutions are there to reducing by-kill? After all, installing cameras would only be the first step in assessing the scale of the problem, not removing it. Since Australia started monitoring its long-line tuna fleet, there has been a whopping seven hundred percent increase in the reporting of seabird and marine mammal by-kill. Some seaboard states in the USA have already banned set netting, which is still in widespread use in New Zealand. Several areas around the New Zealand coast such as between Kaipara Harbour and Mokau already prohibit this method of fishing - in this case to protect the few remaining Māui's dolphin - so there are precedents.

In addition, there are programmes currently testing new technology that may provide the answer. In 2002 the now charitable trust Southern Seabird Solutions was created to reduce by-kill of albatross and other endangered pelagic species.  This alliance of fishing industry leaders, recreational fishers, researchers and government analysts are trialling wondrously-named devices such as the Brady Bird Baffler, Hook Pod, tori lines and warp scarers.

Elsewhere, nocturnal experiments have been conducted using acoustic pingers to deter dolphins, although the results to date aren't especially promising. Equally dubious is the amended trawl net design for squid fishing vessels that incorporates the Sea Lion Exclusion Device (SLED); only today, it was reported that a juvenile sea lion had been found dead in such a net. Clearly, STEM ingenuity is being brought into play, but it will require further development and widespread introduction of the best solutions without industry interference in order to minimalise by-kill.

There are also some simple changes of practice that don't require equipment, only for the boat crews to be more aware of wildlife and act accordingly. Such procedures include moving away from areas with marine mammals present, not dumping offal, recovering lost gear, and changing the operating depth and retrieval speed of nets.

As usual, the financial considerations have taken precedence over the ecological ones. New Zealand has a comparatively small economy and as seafood is the nation's fifth largest export earner - over one billion dollars annually - it is hardly surprising that successive governments have tended to side with industry rather than environmentalists. However, could it be that there is now enough apprehension about the general state of the oceans to overhaul the sector's laissez faire practice? After all, in 2007 a fishing ban in New Zealand waters was placed on orange roughy, whose rapid decline caused huge concern.

There are of course plenty of other environmental issues affecting marine life: plastic pollution (including microbeads); increasing temperature and acidity, the latter especially drastic for shellfish; offshore algal blooms due to agricultural nutrient run-off; and numerous problems created by the oil and gas industry, from spillages to the far less reported exploratory air guns that impact cetacean behaviour.

The longer I've been writing this blog the more I'm convinced that science cannot be considered independent of the wider society in which it exists. Social, political and religious pressures and viewpoints can all adversely affect both what research is funded, what the time constraints are and how the results are presented or even skewed in favour of a particular outcome.

In the case outlined above, government ministries hid evidence to protect short-term industry profits at the expense of long-term environmental degradation - and of course the increase in public spending the latter will require for mitigation. New Zealand's precious dairy sector is already taking a pounding for the problems it has knowingly generated, so no doubt the fishing industry is keen to avoid a similar fate.

By allowing such sectors to regulate and police themselves and thus avoid public transparency, the entire nation suffers in the long run. We don't know what the decline or disappearance of populations of for example wandering albatross and Māui's dolphins might have on the (dis)appearance of snapper or blue cod at the dinner table, but as the alarming loss of Mediterranean and Californian anchovies and sardines suggests, negative cascades in the food chain can occur with extreme rapidity. Natural selection is a wonderful method of evolution but we are pushing it to the limit if we expect it to cope with the radical changes we are making to the environment at such a high speed. By-kill is something we can reduce, but only if industry and governments give science and the public a 'fair go'. Now isn't that something New Zealanders are supposed to be good at?