Arxiu d'etiquetes: spain

BASIC BIOLOGICAL TERMS, CONTENTS, ENGLISH, ENVIRONMENT, ENVIRONMENT: GENERAL

What is an exotic species and an invasive species?

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The concept of exotic species is being more present in the press due to some famous cases like apple snails, monk parakeets, American minks, pond sliders and red swamp crayfishes in Spain. Here we will focus on defining the concept of exotic and invasive species and what we can do to avoid their presence. 

EXOTIC SPECIES AND INVASIVE SPECIES: DIFFERENT CONCEPTS

An exotic species, known also as introduced, alien, non-native or non-indigenous species, is that foreign species that have been introduced in a zone out of its natural distribution. This introduction usually happens for human causes, either voluntarily or involuntarily. The opposite concept is indigenous species.

It is necessary not confusing the first concept with the concept invasive species. A species is invasive when, being exotic or indigenous, the increase of its population supposes an environmental problem, so put in danger the rest of the species present in the specific zone. Despite most of the invasive species are exotic, there are also some cases in which can be indigenous. To give an example, if in a forest disappears the main predator of a particular species, this can increase the number of individuals, so it can become an invasive species.

Les espècies (Foto extreta de Swapsushias).
The concept of exotic and invasive species are different, but most invasive species are exotic (Picture from Swapsushias).

It’s advisable to highlight that the establishment of exotic species in a specific zone is not easy, so the ecosystems have some filters that have to be exceeded. The first barrier that have to be exceeded is the geographical separation between the origin and the arrival point. Then, it can just establish if it has the ability of surviving in the new habitat and of reproducing. Finally, the species would be able to spread and, in this way, it is an exotic species that can become invasive.

IMPACT OF EXOTIC SPECIES

The presence of exotic species, by itself, not necessarily represent a problem. Imagine a field of potatoes or corn, which come form America and don’t suppose an environmental problem by themselves. In most of the cases, the problem is when they become invasive species, which represent a worldwide problem, especially in islands and archipelagos, for the impact that they suppose:

  • Alteration and degradation of habitat.
  • Biodiversity loss.
  • They can suppose a health problem.
  • They can suppose a negative impact on economy, for the negative effect on natural resources and on tourism.

NUMBERS IN SPAIN

According to the Spanish Catalogue of Invasive Exotic Species, inside the Spanish territory there are 13 invasive exotic species of algae, 75 of plants, 14 of non-arthropod invertebrates, 26 of arthropods, 19 of fishes, 4 of amphibians, 4 of reptiles, 17 of birds and 15 of mammals.

El musclo zebra és una de les moltes espècies exòtiques invasores presents a Espanya (Foto extreta de El mon d'en Cotildu).
Zebra mussel (Dreissena polymorpha) is one of the many invasive exotic species present in Spain (Picture from El mon d’en Cotildu).

WHAT CAN I DO?

  1. Acquisition of pets:
    • To acquire pets in specialised shops to guarantee the legal and healthy security.
    • Don’t abandon or free exotic species in the nature.
    • Don’t acquire invasive species.
  2. In the garden:
    • Plant indigenous species.
    • Never throw ornamental plants, aquarium plants or pieces of exotic plants in humid zones or rivers.
  3. Travelling:
    • Don’t transport animals, plants or seeds without declaring them from a country to another.
    • Clean the soles of your boots and your equipment before doing hiking in a new zone.
  4. Fishing:
    • Don’t transport water from a place to another.
    • Don’t use exotic bait.

REFERENCES

Difusió-anglès

CONTENTS, ENGLISH, ENVIRONMENT, FISHES, Impact of fishing, MARINE ENVIRONMENT, ZOOLOGY

Sharks: predators as prey

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Today we will talk about a sensitive topic. This topic is shark finning, an unsustainable and macabre practise that happen in our waters. 

INTRODUCTION

Sharks, together with rays, are included in the elasmobranchii group. They are characterized by a cartilaginous skeleton and several teeth rows, which are continuously renovated. Sharks are predators because they are in the top of food chains. It means that they devour but they aren’t devoured. Nevertheless, we will see that is not completely true, as there is a species that has the ability to capture them, cut their fins and then to throw them to the sea.

WHAT IS SHARK FINNING?

Shark finning consists on cutting and saving shark fins and discard the rest of the body.

4145Fisher cutting a shark fin (Foto: Gary Stokes; Sea Shepherd, Hong Kong).

The animal usually is still alive when is thrown into the water, so it can swim and sink slowly to the deep sea; where, still alive, will be food for other animals. Fishers only save the fins because its economical value is much bigger than the meat of the animal so, discarding the body, they have more space in the ship for fins. In the next video, which is very hard to see, we can watch this activity:

IS THAT ILLEGAL?

Shark finning is a forbidden activity around Europe since 2003, with the passing of the Council Regulation (EC) No 1185/2003 of 26 June 2003 on the removal of fins of sharks on board vessels, but this law allowed to discharge fins without its body, with a permission, and in the case that the fin weight was lower than 5% of the total weight of the animal. This means that, despite the law, finning was taking place. This regulation had some legal vacuums, thanks to 4th article, that allowed to give special permissions to cut fins on board of the vessels and discharge these fins and the rest of the body in different harbours, what meant a big difficulty to control finning.

For all this reasons, in 2011, European Commission proposed the obligatory nature to discharge fins together with the shark body, what was well received by conservationist organisations, most of the scientific community, general public, Committee of Ministers of EU and the Environment Committee of EU. Nevertheless, Spain and Portugal, whose shark fisheries are by far the most important in EU, express their opposition to this reform. Both countries have a fishing line fleet in the North Atlantic.

Finally, in June 2013, it is approved the reform of the European reform about finning, Regulation (EU) Nº 605/2013 of the European Parliement and of the Council (of 12 June 2013), amending Council Regulation (EC) No 1185/2003 on the removal of fins of sharks on board vessels. In this regulation, it is mandatory to discharge sharks with their fins. This measure has been successfully to fight against finning in other parts of the world. Portugal and Spain were put up it because it reduces their benefits, so holds are full sooner.

WHY IS THAT HAPPENING?

This practise was expanded due to the high price of shark fins in the Asiatic market to do shark fin soup and in traditional cures. Every single kilo of fresh or frozen fin costs 20 €, while in the case of meat the value is just 1€. EU captures sharks in the Mediterranean and the Atlantic, Indian and Pacific oceans. It is the first worldwide power in shark fishing, with a 17% of declared captures in 2009, and the biggest fin exporter at Hong Kong and China.

_MG_7002Shark fins spread in the ground to be dried (Gary Stokes; Sea Shepherd, Hong Kong).
_MG_7411Shark fins spread in the ground to be dried (Gary Stokes; Sea Shepherd, Hong Kong).

WHICH SPECIES ARE THE TARGET?

Nowadays, many species are target of fishing because, despite 28% of the species are considered threatened by IUCN, just some of them are protected. In Spain and Europe, there are just 9 protected species. In addition, catch shares don’t exist and, for this reason, fishers can fish till extinction. Why do not exist catch shares? The reason is that fishing regulation in EU is conditioned by Spain and Portugal. However, specialists estimates that every year are killed 100 million sharks for their fins.

Blue shark is the main species in the Atlantic fishing line feet. If we have a look in the capture statistics of this shark in Vigo harbour (Spain) (2468 tones and more than 3 million euro of benefit, according to Puerto de Vigo), we can observer that is a great benefit: is legal, there aren’t catch shares and fins are well-paid in Hong Kong market.

WHICH IS THE IMPACT OF SHARK FINNING?

Shark finning has the following impacts:

  • Loss and devastation of shark populations around the world. Experts estimate that within a decade, most species of sharks will be lost because of longlining.
  • Unsustainable fishery. The massive quantity of sharks harvested and lack of selection deplete shark populations faster than their reproductive abilities can replenish populations.
  • Threatens the stability of marine ecosystems.
  • Obstructs the collection of species-specific data that are essential for monitoring catches and implementing sustainable fisheries management.
  • Wasteful of protein and other shark-based products. Up to 95 per cent of the shark is thrown away.

REFERENCES

ACKNOWLEDGEMENT

I wouldn’t finish this article without give thanks for her help and patient to Mónica Alonso Ruiz, who is communication responsible and Madrid responsible of Alianza Tiburones Canarias, who informed me and give me most of the information and data present here.

If you find this article interesting, you can share it in Social Networks to dissiminate this problem. The goal of this blog is to inform people about science. 

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