Arxiu de la categoria: MARINE ENVIRONMENT

This is the state of the planet: Living Planet Index 2018 (WWF)

Even though nature provides us with everything our modern society needs, our relationship with her is rather destructive. All the impact that our society has inflicted on Earth has led to a new geological era, which experts have baptised as Anthropocene. The Living Planet Report shows us what is the state of the planet. Do not miss it!


This is not the first time that we make a summary of the Living Planet Report, carried out by the WWF and, with this latest edition, turns 20 years and has the participation of more than 50 experts. Previous reports stressed the remarkable deterioration of Earth’s natural systems: both nature and biodiversity are disappearing at an alarming rate. In addition, it is estimated that on a global scale nature provides services valued at around 110 billion euros per year.


According to a recent study, the main threats to biodiversity are two: overexploitation and agriculture. In fact, 3 out of 4 species of plants, amphibians, reptiles, birds and mammals extinct since 1500 disappeared due to these two reasons. This is due to the huge growth of consumption worldwide, which explains that the ecological footprint has increased by 190% in the last 50 years.

sobreexplotacion, agricultura, amenazas biodiversidad, informe planeta vivo 2018, wwf
Overexploitation and agriculture are the main threats for biodiversity (Picture: Ininsa, Creative Commons).

The demand for products derived from ecosystems, linked to their lower capacity to replace them, explains that only 25% of the earth’s surface is completely free of the impacts of human activities. This fraction is expected to be only 10% by 2050.

Soil degradation includes the loss of forest, with the highest rate of deforestation in tropical forests, which harbour the highest levels of biodiversity. Soil degradation has diverse impacts on the species, the quality of the habitats and the functioning of the ecosystems:

  • Biodiversity loss.
  • Alteration of the biological functions of biodiversity.
  • Alteration of habitats and their functions.
  • Alteration of the wealth and abundance of the species.

Invasive species are also a common threat, the dispersion of which is associated with trade. Pollution, dams, fires and mining are additional pressures, in addition to the increasing role of global change.


The Living Planet Index (LPI) is an indicator of the state of global biodiversity and the health of the planet. It is established by calculating the average abundance of about 22,000 populations of more than 4,000 different species of fish, amphibians, reptiles, birds and mammals from around the world.

The global LPI shows that the size of vertebrate populations has decreased by 60% in just over 40 years (between 1970 and 2014).

indice planta vivo, tortuga marina, wwf, marc arenas camps, flores island, komodo national park, indonesia
Vertebrate populations has been reduced a 60% in just over 40 years (Picture: Marc Arenas Camps ©).

If we distribute the analysed species into biogeographic realms, as the lower image shows, we can observe differences in the LPI. The most pronounced population declines occur in the tropics. The Neotropical realm has suffered the most drastic decline: 89% loss respect the year 1970. On the other hand, in the Nearctic and Palearctic the reductions have been much lower: 23 and 31% respectively. The other two realms have intermediate declines, although important: in tropical Africa it is 56% and in the Indo-Pacific 64%. In all the realms, the main threat is the degradation and loss of habitats, but variations are observed.

reinos biogeograficos, indice planeta vivo 2018, wwf
Biogeographic realms of the LPI (Image: Modified de WWF).

Unlike recent reports, in which the index was separated according to whether the populations were terrestrial, marine or freshwater, in this edition only the freshwater LPI has been calculated. These are the most threatened ecosystems since they are affected by the modification, fragmentation and destruction of habitats; the invasive species; excessive fishing; pollution; forestry practices; diseases and climate change. Analysing 3,358 populations of 880 different species it has been calculated that the freshwater LPI has decreased by 83% since 1970, specially the Neotropical (94% decrease), the Indo-Pacific (82%) and tropical Africa (75%) realms.


Despite political agreements for the conservation and sustainable use of biodiversity (Convention on Biological Diversity, COP6, Aichi Targets…), global biodiversity trends continue to decline.

As indicated in the Living Planet Report, “between today and the end of 2020 there is a window of opportunity without equal to shape a positive vision for nature and people.” This is because the Convention on Biological Diversity is in the process of establishing new goals and objectives for the future, adding the Sustainable Development Goals (SDGs). In the case of the SDGs, these refer to:

  • SDG 14: Conserve and sustainably use oceans, seas and marine resources for sustainable development.
  • SDG 15: Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss.

The authors consider that what is needed are well-defined goals and a set of credible actions to restore the abundance of nature until 2050. To achieve this, the authors recommend following three steps:

  1. Specify clearly the objective of biodiversity recovery.
  2. Develop a set of measurable and relevant indicators of progress.
  3. Agree on a package of actions that together achieve the objective within the required time frame.


Looking at the data from the Living Planet Report 2018, it is evident that nature is in retreat: we have lost 60% of the vertebrate populations of the planet, despite the differences between the different areas. In addition, environmental policies are not enough to stop this trend. Therefore, more ambitious policies are needed to stop and recover the nature of the planet in which we live. We have an obligation to live with nature, not against nature. If we do not have more sustainable and respectful habits with the environment, the benefits that nature brings us will be lost and will affect our own survival.

You can read the full report at WWF.

War against plastic

The fact plastics cause problems in ecosystems, biodiversity and human health is well known. In fact, being aware of this, the European Union win ban in 2021, some single-use plastic objects and has established some measures for others. Let’s see what we can do to fight this war against plastic!



According to a study published in 2015, it is estimated that there are 5.25 trillion plastic particles in the world’s oceans, equivalent to a weight of 268,940 tons. If we focus only at the Mediterranean Sea, there are about 2,000 tons of plastic particles. It is also known that 80% of marine plastic comes from land. Another study points, in addition, that by 2050 there will be more plastics than fish in the seas and oceans of the planet not to stop the current trend.

pantai pede, labuan bajo, indonesia, plasticos, basura marina, plastico marino, guerra plastico, residuo zero
In a beach of Labuan Bajo, Indonesia, it was strange not to find waste or plastic in every single step (Picture: Marc Arenas).

As we already talked in this other article, marine litter, of which 75-85% are plastics, causes serious problems in biodiversity, its habitats and the economy. In fact, it is known that every year one million birds and 100,000 marine mammals die from plastic.

The problem of plastic also affects our health. According to a study published in the recent weeks, microplastics have been detected in the excrements of all people who participated in the study. The presence of plastics in the body can be dangerous for the immune system and cause diseases due to their toxins.


We must recognise that, nowadays, living without plastic is quite complicated. The reason is that it is infinitely easier to find a product in a plastic container than in a glass one, or even without it, that is, in bulk. Does this mean that we cannot beat the plastic battle? Obviously, not, but we’ll have to make a little effort.


We have already said that the European Union will ban some plastic items in 2021. These objects are plates, glasses and cutlery, drinking straws and cotton buds. Considering that in two years we will not find them in the stores, go ahead to the prohibition and implement these alternatives.

Using plastic cutlery, plates and cups at a party with many people is comfortable, and if they are colourful it is even fun, but it is totally unsustainable. Alternatives:

  • In the market you can find these objects made with alternative materials. In particular, they are usually made of corn, so that when you finish your party or picnic you can throw them into the organic fraction, since they are compostable. You can also find them in paper, although they are less resistant and less sustainable.
  • Another alternative is to use your metal cutlery, your ceramic dishes and your crystal glasses. Simpler, smarter and more sustainable!

Plastic straws are a problem for the environment, since many of them end up in the sea.

In the United States alone, 500 million straws are consumed every day. Maybe you are going to think that this is why it is a very populated country. Well, in Spain every day 13 million are consumed and it is the European country in which they consume the most. If you are one of those who need (need!) to drink a soft drink or cocktail with a straw, we have an alternative for you.

  • At home, we can use reusable bamboo or metal straws. They are equally effective and you will be collaborating to avoid images like the ones in the video being repeated.
  • Do you really need to drink with a straw? If you only find plastic straws in a bar, pub, club or restaurant, reject it (but before they bring you the drink!). Surely you will survive!

The ear buds are another of the prohibited objects from 2021 since it is one of the most found among marine debris.

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Cotton buds will be forbidden from 2021 (Picture: Justin Hofman)

Apart from the fact that the health authorities only advise its use for the external ear, if you cannot avoid its use, you should opt for alternatives to the plastic ones:

  • Use cotton buds made with bamboo or other woods which, in addition, are sold in recycled cardboard boxes.
  • If you want to be even more sustainable and reduce your garbage production, there is another better alternative: buy a metal stick as we recommend in this article and put a piece of clean cloth on a tip to absorb the water from the shower.


Plastic bottles also harm the environment. Did you know that it takes up to 1,000 years to degrade one bottle? In addition, to make each plastic bottle it is needed 100 mL of oil. For sure, many of you will be thinking about water, but the truth is that this also applies to soaps, detergents, softeners… Seeing how these bottles are accumulating, we give you some tips:

  • Buy larger bottles. It is needed less plastic for a bottle of 1L than for 4 of 250 mL.
  • For the specific case of water, use canteens to avoid the use of plastic. You can drink tap water if in your town has the right quality, but if it is not the case you can install an osmosis or buy water jugs (remember what we said in the previous point).
  • Observe what products you consume at home in plastic bottles and look for a store in your area that sells them in bulk.

Plastic bags, although their use is being reduced, are another problem. In Spain, according to Cicloplast, each year 97,000 tons of plastic bags are consumed, of which only 10% are recycled.

  • How easy and comfortable it is to go shopping with cloth bags, a trolley or a shopping basket!

Finally, we will now focus on polystyrene trays and plastic film. These two elements are increasingly common in supermarkets and homes, since supermarkets sell their fresh product packed in them. Some advises:

  • If your supermarket only sells meat, fish… in these containers, opt for a local store, which will sell it in bulk and you can also buy just the amount you need.
  • Go shopping in bulk stores and take your tupperware (best glass) from home to avoid plasticized paper (which goes to landfills) or the aforementioned objects.

We are aware that we have forgot many things to comment due to plastic is very present in our lives, but the best thing is to become aware of the plastics we generate every day to find an alternative to each of them.

What do you do to avoid the use of plastic? Leave us your advice in the comments for others to join this war against plastic.

(Cover picture: El Observador Crítico)

What’s causing the massive death of the nobel pen shell?

The nobel pen shells are the most emblematic molluscs of the Mediterranean since they only live in this sea. Its drastic reduction due to a parasite has led scientists to declare it as endangered. Do not miss this post to know more about the nobel pen shell and what is leading them to extinction, as well as what is being done and what you can do to save the species! 



The nobel pen shells (Pinna nobilis) are molluscs of the bivalve class. This means that they have a shell formed by two lateral shells, which are joined by a hinge.

The shell of the pen shells is shaped like an ear, hence its scientific name (Pinna), since it has a rounded upper part and the lower one ends in a tip. It is by the lower tip that they are buried in the substrate to hold onto the seabed. It can reach a meter long.

nacra, pinna nobilis, muerte masiva nacra, haplosporidium
The nobel pen shell (Pinna nobilis) is ear-shaped, hence its scientific name (Picture: Doruk Aygün, Creative Commons).

The nobel pen shells are the most characteristic mollusc of the Mediterranean, since it is in this sea the only place in the world where they live. It is, then, a species endemic to the Mediterranean. They are usually found associated with Posidonia meadows and their presence serves as an indicator of good water quality.

Among its threats are the capture by divers, pollution and anchoring of vessels in the Posidonia meadows. Now, anyway, we must add a new threat: a protozoan, which has led it to be in danger of extinction.


A parasite that affects the digestive system of the pen shells is the culprit that they are in danger of extinction. Specifically, it is a protozoan of the genus Haplosporidium, which penetrates the digestive gland. How the pathogen has entered the mollusc is still a mystery.

In any case, it must be a very specific pathogen, since it has not affected its “sister” species, Pinna rudis, which lives in the same areas.


At the beginning of autumn 2016, a massive death of pen shells of the species Pinna nobilis was detected in several points of the Spanish Mediterranean coast.

A study carried out by the Balearic Oceanographic Center of the Spanish Institute of Oceanography has concluded that in most of the Spanish Mediterranean coast there are high mortality rates, up to 100% in some points, especially in the populations of Andalusia, Murcia, Valencia Community and Balearic Islands. In fact, this is the massive mortality event that has most affected the species to date.

nacra, pinna nobilis, muerte masiva nacra, haplosporidium
Map about the situation of Pinna nobilis in different places of the Western Mediterranean coast (Source: Vázquez-Luis et al. 2017).

In this video, you can see a massive death case in Tangó de Xàbia (Valencia Community):

Fortunately, the populations of the Catalan coast still persist, especially those located in Cap de Creus and in the Ebre Delta.

In addition, the high propagation rate of the protozoan could lead to an even worse situation. It is for this reason that it has been declared as a critically endangered species.


A project of the Ministry of Agriculture and Fisheries, Food and Environment of the Government of Spain, with a cost of 491,521 euros, aims to rescue 215 specimens of the species.

The project consists in its extraction, rescue and conservation in different centres, with the final goal of keeping the specimens healthy to avoid their infection, maintain the species, have a genetic reserve and, in the future, repopulate their habitats again and try reproduce the species in captivity.


According to a decalogue from the Spanish Malacology Society, this is what has to be done in case of finding a nobel pen shell.

In case the animal is alive: 

  1. Do not disturb, damage or tear the animal.
  2. Do not touch the animal under any circumstances, since the protozoan generates many spores and could contaminate it.
  3. Do not disturb the animal by putting us on it, lighting it with a flashlight or trying to open its shells.
  4. Try to identify the Pinna species. The young specimens of P. nobilis and P. rudis can be distinguished by the number and size of the ribs of the shells: in P. nobilis they are much smaller and numerous. In larger specimens it is more complicated.
  5. If the animal is covered with organisms, even if they are of invasive exotic species, the animal should be left untouched and untapped.
  6. If the mollusk is alive but lying on the bottom, do not touch so as not to damage it or infect it.
  7. If we see that there are divers or other people touching or bothering an animal, we should gently remove it from the animal.
  8. If we see that a diver or fisherman has captured a live animal and tries to get it out of the water or has done so, we must return it to the sea as soon as possible and call the 112 telephone so that the competent authorities take the appropriate measures.
nacra, pinna nobilis, muerte masiva nacra, haplosporidium, pinna rudis
Pinna rudis can be distinguished from Pinna nobilis by the presence of bigger and less numerous ribs (Picture: Creative Commons)

In case the animal is death: 

  1. If we find an empty shell, we should leave it in the water. It is a protected species.
  2. If we find a dead pen shell with remains of the organism, we should not touch it or move it so as not to expand the pathogen.

Other complementary measures: 

  1. If we are going to dive with a boat or sail, in no case will we drop the anchor if there is Posidonia in the seabed.
  2. If we have dived in areas with death pen shells, we must clean the equipment with diluted bleach or detergent to prevent the spread of the pathogen to other areas.
  3. If you see a live or recently dead specimen of Pinna nobilis, tell it to and to with the subject “Nacra”.


Cetaceans and fishing: a dangerous relationship

The cetaceans are creatures that live in the seas and oceans of the Earth. Like other animals, not only must they cope with natural threats to their environment, such as predation or disease, but they also interact with human activities, such as fishing. Here we will see how fishing threatens the populations of these marine mammals. 


According to a recently report published by Ecologists in Action, the main threats of anthropic origin that cetaceans have to overcome are fishing, aquaculture, submarine noise, collisions with boats, marine litter, chemical pollution, sighting tourism , research, climate change and dolphinariums.

amenazas cetaceos
Cetaceans have to face several anthropic threats and they might beach at coast (Picture: Bahnfrend, Creative Commons)


During the last century, whaling activity captured more than three million individuals worldwide, especially in the southern hemisphere, where according to the IWC, about 750,000 individuals of fin whales (Balaenoptera physalus) and 400,000 specimens of sperm whales (Physeter macrocephalus) were captured, among others.

It is known that until the 1960s, hundreds of thousands of blue whales were captured, the largest animal that inhabits the Earth. Despite conservation efforts, currently only between 10,000 and 20,000 individuals survive, a small part compared to those that inhabited the Earth before the boom in the whaling industry.

industria ballenera, relacion cetáceos pesca
Picture showing whaling (Picture: Creative Commons)

In fact, according to a study by Tulloch et al. (2017), although there is currently an international moratorium and major conservation efforts are being made, in the year 2100 the populations of cetaceans that were the object of catches will reach, at most, by half of its original size.

Contrary to the prohibitions established in 1986, there are countries that continue to catch whales and dolphins. These countries are mainly Japan, Norway and Iceland. It is believed that they capture some 1,500 whales annually together, although the demand for meat from these marine mammals is low. In fact, since the ban, it is estimated that some 30,000 whales have been captured.

In Spain, the capture of cetaceans is also prohibited, although it is believed that there is a small illegal activity.


We must bear in mind the impact of accidental catches, one of the main causes of mortality in cetaceans. It consists in the capture of species that are not the target of fishing.

Bycatch can cause a conservation problem when there are endangered species affected, such as the vaquita (Phocoena sinus), a critically endangered porpoise (there are only about 30 animals left around the world), according to the IUCN. mainly due to gillnets.

Bycatch is one of the main causes of mortality, although at European level some measures have been taken, such as Regulation 812/2004. Accidental capture with the use of driftnets was especially important, but this practice is currently prohibited throughout the Mediterranean. In any case, other fishing gears, such as gillnets, purse seines or trawls, are particularly harmful.

In the 1960s, the tuna purse seine fishery in the Eastern Pacific had a significant impact on dolphin populations. The reason is that the fishermen knew that under the groups of dolphins that swam on the surface there are schools of tuna that followed them to take directionality. Thus, knowing this relationship, they surrounded the cetaceans (and therefore the tuna) with the purse seines, killing the former. It is estimated that in 1986 alone, about 133,000 dolphins were captured. To stop this situation, the pressure of the society was fundamental to take the appropriate measures. In fact, currently less than 0.1% of individuals are captured.

relacion pesca cetáceos, pesca accidental delfines
Fishers related dolphins with tuna, so that purse seine affected them (Picture: Wally Gobetz, Creative Commons)

Now we will focus on a case of gillnets. Gillnets kill many different species of cetaceans, both dolphins and whales. Although whales often survive, they often have traces of fishing gear attached to the body, such as nets. Small cetaceans do not suffer the same fate and often die. We have already seen the case of the vaquita , but another porpoise, the harbour porpoise (Phocoena phocoena) is the cetacean that suffers most deaths from gillnets.

Finally, we will see the relationship between cetaceans and trawling. Many species of cetaceans, both dolphins and small whales, feed on the target species of trawling, so they are caught while they are feeding on their prey. In fact, 16 cetacean species have been reported worldwide that feed in association with trawling. The catches are much greater when nets are left at a medium depth than when fishing is done on the seabed.

Despite all conservation efforts, according to an estimate by Read and collaborators, about 300,000 marine mammals are accidentally caught around the world each year due to fishing operations.


Finally, we cannot forget that cetaceans and fishermen compete for the same resources. Therefore, we must bear in mind that some cetaceans also interact with fishing to get food. Sperm whales, bottlenose dolphins and killer whales have learned to “steal” food from fishermen.

In fact, they take captures from longline, gillnets and trawl nets, running the risk of being trapped.

In any case, some measures have been taken, such as installing devices that emit annoying sounds for animals. Despite the attempts, they have adapted to it and, in fact, in some cases interpret them as an indication of the presence of fishermen in the area.


  • López López, L (2017). Cetáceos: los mamíferos más salaos. Informe sobre las interacciones entre cetáceos y actividades humanas. Ecologistas en acción.
  • Hall, MA; Alverson, DL & Metuzals, KI (2000). Bycatch: Problems and solutions. Marine Pollution Bulletin Vol. 41, N 1-6, pp. 204-219.
  • Northridge, S (2009). Bycatch. In Perrin, WF; Würsig, B & Thewissen, JGM (Eds). Encyclopedia of Marine Mammals (pp.167-169). Academic Press (2 ed).
  • Whale and Dolphin Conservation: Stop Whaling
  • World Wildlife Foundation: The Vaquita
  • Cover picture: Omar Vidal (source)

The impact of marine debris on nature

Marine debris has a negative impact on the environment. For this reason, it is considered to be one of the most serious problems affecting the marine environment, together with climate change, ocean acidification and the loss of biodiversity. Do you want to know more about that?



Marine debris is any persistent, manufactured or processed solid material discarded, disposed of or abandoned in the marine and coastal ecosystem.

Debris can be made of glass, metal, paper or plastic, but plastic items are the most abundant on a global scale. For example, on European beaches, about 75% of all debris are plastics, followed by metal and glass (OSPAR, 2007).

impacto basura marina, impacto naturaleza basura
Most of the marine debris is plastic (Picture: U.S. Fish and Wildlife Service Headquarters, Creative Commons)

It is considered that most of the marine debris come from land-based sources, such as urban and storm runoff, beach visitors and inadequate waste disposal and management, among others.

Unfortunately, marine litter has been found all over the globe: from the poles to the equator, from shorelines to the high seas, from the sea surface to the seafloor.


Marine litter is well-known to have a negative effect to organisms and ecosystems, but also to economy. This is going to be discussed in the following sections.


The environment and the flora and fauna is affected by marine debris in several ways: by entanglement in or ingestion of debris, transport of contaminants over long distances, new habitat for colonisation, dispersal via rafting and effects at an ecosystem level. Notwithstanding, half of the interactions between organisms and debris were related with entanglement or ingestion.

Entanglement and ingestion of debris is the most common interaction between debris and organisms (Picture: Unknown, Creative Commons).

In fact, impacts of marine debris have been reported for 663 species (Secretariat of the Convention on Biological Diversity and the Scientific and Technical Advisory Panel – GEF, 2012).

All sea turtle species, half of marine mammals and 21% of sea bird species are victims of entanglement or ingestion of marine debris. Overall, about 15% of species are on the IUCN Red List, such as the critically endangered Hawaiian monk seal (Monachus schauinslandi) and the endangered loggerhead turtle (Caretta caretta).

impacto basura marina animales
The critically endangered Hawaiian monk seal is a victim of marine debris (Picture: Kent Backman, Creative Commons).

Despite the frequency of entanglement or ingestion varies according to the type of debris, in the 80% of the cases it was plastic items that were found, specially rope and netting (24%) and fragments (20%), followed by packaging (17%), other fishing debris (16%) and microplastics (11%) (Secretariat of the Convention on Biological Diversity and the Scientific and Technical Advisory Panel – GEF, 2012).

Not only the entanglement or ingestion can cause direct death, but also can have sublethal outcomes, such as making it difficult to capture and digest food, sense hunger, escape from predators, reproduce, as well as decreasing body condition and complicating locomotion and migration.

An example of sublethal effects occur with sea turtles: turtle hatchlings find it more difficult to reach the sea when litter is present (Ozdilek et al., 2006).

Microplastics (fragments less than 5 mm in diameter) are of particular concern due to their susceptibility to be eaten by a wide range of organisms. They come from either the direct release or through the fragmentation of larger units.  These particles, when ingested, may cause adverse physical and toxicological effects on organisms. Moreover, these small pieces are susceptible of bio-accumulation throughout the food web.

Moreover, microplastics can easily absorb pollutants and other harmful chemicals, such as persistent organic pollutants (POPs), that, when introduced into the body, can be freed and affect the health of the individual. It has to be taken into account that all plastic sizes can absorb pollutants, so those which are buoyant have the possibility to disperse these chemicals to other areas, thousands of kilometres away.

Buoyant debris has the possibility to disperse toxic chemicals to other areas, thousands of kilometres away (Picture: Cesar Harada, Creative Commons).

Aside from the absorbed chemicals, plastics also have potentially toxic chemicals by itself, such as BPA, flame retardants and antimicrobials, which could be released into the environment and then be transferred to the food web and humans, with adverse consequences.

Another important issue is the accumulation of plastic items and microplastics in specific regions, such as the North Pacific Central Gyre or the north western Mediterranean. In both areas, about 1,340 particles of microplastics per square metre have been found (Goldstein et al., 2012; Collingnon et al., 2012).

Marine litter can serve as a means of transport for many species, with the potential risk to facilitate transport of exotic and invasive species.

impacto basura marina especies exoticas
Marine litter can serve as a means of transport for exotic species to other areas (Picture: Thank You Ocean).

As mentioned above, marine debris can be a potential new habitat for some species, altering the equilibrium in some areas such the open ocean or sandy seabeds. They would be, first, colonised by microorganisms and, then, by macrobiota, like molluscs, crustaceans, fishes, cnidaria and echinoderms. In case the debris floats, the organisms can be transported to other regions. So, debris may be responsible for the introduction of exotic species.

Finally, in some ecosystems the negative effect of debris has been described, such as on coral reefs, soft sediment habitats and in the sandy intertidal zone.  To give an example, in coral reefs from Majuro Atoll coral cover and species diverisity decreased with increasing debris abundance.

Ghost fishing, accidental fishing from lost or abandoned nets, apart from the economical impact, also negatively affects the populations of wild animals such as turtles, cetaceans, sea birds and fishes.

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The effects of ghost fishing (Picture: Doug Helton/NOAA)
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The effects of ghost fishing (Picture: Marion Haarsma).


Marine debris can have a negative effect on economy because of economic losses to commercial fishing and shipping, in addition to recreation and tourism.

The economic loss for the fishing industry can be important. For example, Scottish losses are between US $ 15 – 17 million per year (KIMO, 2008) due to the loss of fishing time and repairs for removing debris from fishing gear, propellers and water intake pipes.

Ghost fishing means a removal of commercial species from the fishery. In Oman, the cost of ghost fishing was US $145 per trap after 3 months and US $168 after 6 months (Al-Masroori et al., 2004).

Removing debris from harbours and beaches also reduces the revenue. In the UK, removing litter from harbours amounts to US $3 million per year (Mourat et al., 2010).

Tourism is also affected by marine debris, since reduces the attractiveness of the coastline and beaches. Thus, activities such as sport fishing, whale watching and diving are reliant on healthy ecosystems.

impacto basura marina economia
Tourism may be negatively effected by marine debris (Picture: Zak Noyle).

Marine debris has a huge impact on the environment and economy. Now, watch that video, think about it and take action.

What are you willing to do for reducing all these negative effects? Leave your comments!


  • Al-Masroori, H., Al-Oufi, H., McIlwain, J. & McLean, E. (2004). Catches of lost fish traps (ghost fishing) from fishing grounds near Muscat, Sultanate of Oman. Fisheries Research, 69, 407-414.
  • Collignon, A., Hecq, J., Galgani, F., Voisin, P., Collard, F. & Goffart, A. (2012). Neustonic microplastic and zooplankton in the North Western Mediterranean Sea. Marine Pollution Bulletin 64, 861-864.
  • Goldstein, M., Rosenberg, M. & Cheng, L. (2012). Increased oceanic microplastic debris enhances oviposition in an endemic pelagic insect. Biology Letters n press doi: 10.1098/rsbl.2012.0298.
  • KIMO. 2008 Fishing for Litter Scotland Final Report 2005 – 2008 (ed. K. I. Miljøorganisasjon), pp. 20: KIMO.
  • Mouat, T., Lopez-Lozano, R. & Bateson, H. (2010). Economic impacts of Marine litter, pp. 117: KIMO (Kommunenes Internasjonale Miljøorganisasjon).
  • OSPAR (2007). OSPAR Pilot Project on Monitoring Marine Beach Litter: Monitoring of marine litter on beaches in the OSPAR region. London: OSPAR Commission.
  • Ozdilek, H; Yalcin-Ozdilek, S; Ozaner, F & Sonmez, B. (2006). Impact of accumulated beach litter on Chelonia mydas L. 1758 (green turtle) hatchlings of the Samandag coast, Haty, Turkey. Fresenius Environmental Bulletin. 15. 95-103.
  • Secretariat of the Convention on Biological Diversity and the Scientific and Technical Advisory Panel – GEF (2012). Impacts of Marine Debris on Biodiversity: Current Status and Potential Solutions. Montreal, Technical Series. No. 76, 61 p.
  • Thevenon, F., Carroll C., Sousa J. (editors), 2014. Plastic Debris in the Ocean: The Characterization of Marine Plastics and their Environmental Impacts, Situation Analysis Report. Gland, Switzerland: IUCN. 52 pp.
  • Cover picture: ©Jordi Chias/

Farm fishing: the solution to overfishing?

We have heard many times that fishing grounds are being depleted due to the overexploitation of species. It is also widely said that farm fishing could solve this problem. But, are farms the solution to overfishing?


In general terms, the status of wild fish stocks has not improved. By 2013, 58.1% of fish stocks were fully exploited, 10.5% were under-exploited and 31.4% were overexploited (FAO, 2016). Thus, 30% of the populations suffered from overfishing.

This is due to the increasing consumption of fish. According to a report published by FAO, in 2014 each person ate on average about 20 kg of fish, twice as much as in 1960.

On the other hand, since the 1980s, wild catches have remained stable. However, the supply of fish for human consumption has increased considerably. So, if consumption has increased and fishing has remained stable, where does the rest of the fish come from?

The explanation for this fact is in aquaculture: in 2014, catch production was 93.4 million tonnes, while aquaculture production amounted to 73.8 million tonnes. In other words, 44% of the fish came from aquaculture.

Evolution of capture production and aquaculture production (Source: FAO, 2016).

Looking at this scenario, it does not seem far-fetched to think that farm fishing could solve the problem of overfishing.


According to the UN World Population Prospects report, by 2050, the world population will have risen to 9.7 billion people.

Given these figures, we can think that the increase in fish consumption will grow well above the production capacity of the oceans and seas. Aquaculture could therefore respond to this increase in the demand of fish for human consumption, in order to meet protein requirements.

Wild populations, therefore, will not be subject to greater pressure than they are now.

Another advantage of fish farms is that production is constant because they have more control over them, that is, there are few fluctuations during the year. This is not true for wild populations, either because of their biological cycle or because they are overexploited.

Finally, farms could reduce the environmental impact caused by fishing: there would be no incidental catches of non-interest species, seabed would not be eroded by trawling…

If you want to know more about aquaculture, I recommend you to watch this video (in this case is about river fishes):

Despite all these advantages, not only are not farms a solution, they also increase the problem of overfishing and cause many other problems.


Half of the cultivated species (including both animals and algae) in aquaculture do not require food from outside, because they feed by filtration. Anyway, it is true that this is not the case for carnivorous species.

Without going any further, according to FAO (2016), in 2014, 21 million tons of fish were destined for non-food products, three quarters of which were used to produce fishmeal or fish oil, the main component of feed for carnivorous species of the fish farms.

piscifacotrias solucion sobreexplotacion
Fish from farm fishing is feed by feed based on wild fish (Picture: Yousuf Tushr, Creative Commons).

In other words, to feed fish from fish farms, wild fish have to be caught, which exacerbates the problem of overfishing. According to FAADA, between 3 and 5 tons of wild fish are needed to feed a ton of farm fish.


We have already seen that aquaculture needs to catch wild fish in order to feed the species under cultivation. Now we are going to see other problems for the animals themselves and the environment.

Due to the fact that the cages are installed at fixed points, in the surrounding waters and on the seabed there is a significant accumulation of nutrients and chemicals from feces and uneaten food. This can cause a bloom of algae, which deplete oxygen and, depending on the species, can cause the production of toxic substances.

However, in some cases some measures have been implemented, such as changing the position of cages every year or placing them in areas with strong currents.

The use of antibiotics and vaccines is frequent to prevent or treat diseases as the stress makes them more susceptible. In fact, in the cages the mortality is around 10 to 30%.

impactos ambientales piscifactorias
Diseases and parasites, such as sea lice, are a common problem in farmed fish (Picture: 7Barrym0re, Creative Commons).

Another important problem is that genetically modified fishes are often used. If by accident or by the effect of predators, these organisms escape and mate with their wild relatives, a significant change in the genetic composition of the species can occur (genetic pollution). In fact, between 1992 and 1996, about 1.3 million salmons escaped each year from farms in Norway. Another effect of the leaks is the transmission of diseases and parasites to the wild organisms.

Another disadvantage of farms is that non-native species are often cultivated, that is, species that do not belong to the area in which they are caged. Their escape may involve competition for resources (both food and habitat) with native species. We have already seen that exotic species are a problem for biodiversity.

As we have said, predators can be a problem for companies engaged in fish farming. The solution to this threat is their control or killing, thus affecting their populations.



We have seen that farms have a number of advantages to solving the problem of overfishing. In any case, feeding farmed fish with wild animals further increases the problem of overfishing; in addition to the other existing problems.

What do you think: are the advantages of fish farms more important than their drawbacks? Leave your opinion in the comments of this article.


What’s the function of a marine reserve?

The fact human beings benefit from the sea in many different ways is undeniable. Despite this, it seems we have forgotten this since our actions are slowly degrading the oceans. It is for this reason that have emerged different management tools, such as marine reserves. But, what are they and what is their function?


Marine reserves are areas protected by fishery legislation with the aim of regenerating fishing resources and traditional artisanal fisheries in a particular area. Thus, a marine reserve is an area where fishing is forbidden.

This concept might easily be confused with a marine protected area (MPA). According to the WWF, they refer to any marine and coastal area defined by legislation to protect their ecosystems, ecological processes, habitats and species that can contribute to the restoration of social, economic and cultural resources.

In fact, although they are not comparable concepts, they largely overlap.

mediterraneo reserva marina
The concepts marine reserve and marine protected area are not equal, but similar (Picture: Enric Sala).


Marine reserves are not homogeneous from the point of view of the uses that are allowed in them.

Most reserves have an area in which any use is allowed, known as integral reserve. In these areas there is a lack of fishing.

In the rest of the reserve, however, artisanal fishing, diving, anchoring, recreational fishing… are regulated. Artisanal fishing is allowed to usual professionals in the area. Diving, on the other hand, has to be respectful to the environment. Thus, the maximum number of fishing boats and diving quotas are established.

buceo recreativo, reservas marinas
Diving is regulated in marine reserves by establishing the maximum number of divers (Foto: Maria José Ochoa Muñoz, Creative Commons).

Do you fish (recreational fishing) in marine reserves? Here you can know the impact of this activity.


The creation of marine reserves generates a set of benefits at different levels.

The general public is often unaware of the marine environment and life for the simple fact that are hidden underwater. Thus, marine reserves are a tool for dissemination of natural heritage with great potential.

Another benefit is the fact they are good places to develop scientific research: are usually monitored, allow a better understanding of the ecosystem, allow to have long-term data from the same area and there is a control of its evolution over time.

They also permit the development of different economic activities, although this should not be the main goal. Activities such as diving and snorkeling are common in these areas, and increases the number of visitors in the vicinity of the reserve.

Although the above benefits are important, the reserve effect is the main objective sought when creating a marine reserve.


The reserve effect refers to the conservation of the ecosystem’s diversity and the conservation of ecosystem services.

efecto reserva marina
The reserve effect is the main goal sought when creating a marine reserve (Picture: Ocean Conservancy).

Among its benefits, there are:

  • Reduction of mortality caused by fishing or derived from habitat destruction.
  • Increase of the size and abundance of populations (rebuilding).
  • Increase of the size (and age) of target species and density of breeding individuals.
  • Increase of the reproductive capacity of populations: Being larger, they have a higher reproductive capacity. Moreover, as more individuals are present, it increases the number of lays and the production of eggs and larvae.
  • The natural characteristics of habitats and marine communities recover as all trophic levels and trophic cascades recover.
  • Species of flora and fauna that are not of commercial interest are recovered (marine mammals, sea turtles, sea grasses…).

So, they help to reduce the negative effects of fishing both at the ecosystem level and at the level of marine species.

Two clear examples of the reserve effect on species are the grouper (Epinephelus marginatus) and lobsters (Elephas palinuris).

mero Epinephelus marginatus
The grouper (Epinephelus marginatus) is a clear example of the benefits of marine reserves on marine biodiversity (Picture: Parent Géry, Creative Commons).

Its benefits extend beyond the marine reserve when the number of individuals within the reserve reaches its maximum capacity and then they are out of range. Therefore, it increases the density of individuals outside and ecosystems benefit from it. This process is known as spillover.

Not only do ecosystems benefit, but so do the fishermen since they have access to them.


We should note that marine reserves can only work if they are large enough, they are close enough to each other, they are representative of different habitats and marine ecosystems, are sufficient in number and they are actively protected.

In other words, what is really useful for conservation of the marine environment is the creation of a network of reserves, ie, a set of areas that meet the above five requirements.


Although the rules will depend on the specific marine reserve to which we are, we can take the following points as generalities. In a marine reserve it is prohibited:

  1. Perform discharges.
  2. Anchoring on seagrass beds.
  3. Capture or collect protected species. In case of accidental capture, is has to be returned (causing minimal damage).
  4. Feeding wildlife.
  5. Any activity or behaviour that might cause annoyance or harm to whales or sea turtles.


  • Brito, T., González, S. y Miota, F. 2012. Reservas Marinas de Canarias. Dirección General de Recursos Pesqueros y Acuicultura. Secretaría General de Pesca. Ministerio de Agricultura, Alimentación y Medio Ambiente. 24 pp.
  • López-Ornat, A; Atauri, JA; Ruiz, C; Múgica, M. 2014. Beneficios sociales y ambientales de las reservas marinas de interés pesquero. Fundación Fernando González Bernáldez.
  • Ministerio de Agricultura, Alimentación y Medio Ambiente. Guía de buenas prácticas en las zonas especiales de conservación de ámbito marino de Canarias
  • Ministerio de Agricultura, Alimentación y Medio Ambiente. Red de reservas marinas. Más de 25 años protegiendo nuestros mares.
  • Notes of the Master in Oceanography and Marine environment managment
  • The Wildlife Trusts: Marine Protected Areas