MARINE NUISANCES – Plastics in the marine environment around Gibraltar

words | Lewis Stagnetto, The Nautilus Project


Global plastic production is estimated at around 300 million tons per year and this figure is on the rise. Half of that plastic, around 150 million tons, gets thrown away and around eight million tons ends up in the sea. Obviously, as production goes up there is likely to be an increase to the oceanic input of plastic waste into our oceans. “So what!” I hear you say, “that figure is around 2.7% of global production and the sea accounts for over 80% of the planet’s surface, it’s a drop in the ocean” – excuse the pun.

Well, take into account the following information and see how it grabs you: a plastic bottle used for mineral water takes around 450 years to biodegrade. Today’s modern polyvinyl chloride, low density polyethylene, polystyrene, and polymethyl methacrylate were all developed in the 1930’s. Taking into account that these materials biodegrade over a 200-400 year timespan on average, then the first plastic bottles ever made still exist today. Further, these bottles will not disappear from the planet until 2130-2330 CE. Now, add your eight million tons per year over 400 years and you get a total of 3200 million tons of plastic in the oceans. This is before we even start to lose anything to biodegradation and that does not take into account an increase year on year. The situation has become so bad that it has been predicted that by the year 2050, there will be more plastic in the ocean than fish!


Here, in Gibraltar we are pretty lucky because the prevailing currents are constant and efficiently move a lot of our waste out of sight. So, how do we see this problem manifest itself along our dynamic coastline? Next time you walk along a sea front take the time to inspect what is tucked away in between the rocky breakwaters we have scattered around. You might well be forgiven for thinking I am talking about shore crabs or some other organism but you would be wrong. Unfortunately, before you catch a glimpse of any type of life, you will begin to make out plastic debris all over the place. The breakwaters are acting like a natural sampling net collecting some of what makes its way into our seas. Cleaning up the breakwaters is a step in the right direction but preventing the plastic from getting into the sea in the first place is the real goal.

Plastic bags are a terrible offender and most people have probably seen the pictures of turtles and tuna who have mistaken them for a jellyfish and eaten them. Animals cannot digest a plastic bag and will consequently die from having it in their stomachs, but it doesn’t end there. Any animal that attempts to eat the dead turtle is running the risk of ingesting some of that plastic bag and a grim fate awaits them too. Hence, this cycle of death induced by plastic will continue for approximately 40 years before it will have completely decomposed; one plastic bag equals a lot of lost marine life!

Juvenile fish with bloated stomach filled with plastic microbeads
Juvenile fish with bloated stomach filled with plastic microbeads

Microbeads, used in exfoliation creams and shower gels, are some of the worst offenders. The beads are so small the human eye cannot see them without help and a single shower can send hundreds of thousands of them into the sea. Once there, they float tantalisingly on the surface where fish in the planktonic stage of their lifecycle begin to feed on them. There are some horrific pictures of these juvenile fish with bloated stomachs filled with plastic microbeads. But if you think the issue ends there then you would be wrong as “out of sight out of mind” comes back to haunt us. The planktonic fish are slow due to a lack of energy and bloated stomachs. This makes them more likely to get eaten by a bigger fish. The beads find their way into the guts of that larger fish and as the saying goes “there is always a bigger fish”. Typically, the bigger fish cycle continues and as it does, the likelihood that said fish ends up on your plate increases. It is very ironic that the very beads we dispose of in the sea, end up in our own stomachs due to our indifference.

Plastic six-pack can holders can become trapped on the rostrum of dolphins as they use it to play in the waves. Once it’s slipped down the rostrum, the animal is unable to open its mouth and with no hands to remove it and no ability to swim backwards, the dolphin will literally starve to death. Only this summer, local authorities were attempting to help a dolphin in our own waters. Catching it was impossible and the animal eventually died. Fortunately, one enterprising brewery in the USA, Saltwater brewery, has developed a completely biodegradable equivalent made out of the by-products of the brewing process. The result is something that is as strong as plastic but also safe for marine animals to feed off. Ideas like this demonstrate how companies can save costs on packaging and waste by-products simultaneously. This is exactly the type of thinking we urgently need.

Plastic six-pack can holder trapped on the rostrum of the dolphin. Without help, the dolphin will starve.
Plastic six-pack can holder trapped on the rostrum of the dolphin. Without help, the dolphin will starve.

Reduce, re-use and recycle are the three R’s which are core to this issue. Reducing the plastic you buy at supermarkets by choosing the loose fruit as opposed to the prepacked variety helps. Re-usable bags for supermarket shopping are a fantastic alternative to single use plastic bags. The ones made from natural fibres are the best as they biodegrade most easily. For our part, we only have to invest in them initially and then remember to take them with us when we go shopping. Recycling is an important defence against this marine pollution as re-using plastic will reduce the need to keep producing more each year.reducereuserecycle

Ultimately, this is not an issue that can be solved single-handedly; we all need to work together if we are to pass on a cleaner environment to our children.