Arxiu d'etiquetes: whale shark

Threats and protection of sharks – Interview with Mónica Alonso

In this blog we have talked about sharks on several occasions, but now we interview Mónica Alonso, a member of Alianza Tiburones Canarias (Canarias Shark Alliance). Although she is an engineer, she has been taking courses on marine biology and elasmobranchs for over 15 years; which have motivated her to create the blog Protejamos las maravillas del mar

Mónica, thank you very much for the interview and for sharing your knowledge and experience about sharks. Being engineer, how did your interest on sharks arise? 

More than 15 years ago, I started to dive, and immediately, I was interested in marine environment, of which I unknown almost everything. I did some courses on marine biology and I was passionate for it.

mónica alonso ruiz alianza tiburones canarias
Mónica Alonso diving

Studding sharks, I realised that they are fascinating, and above all when I started to be conscious about the precarious conservation state of most of the species due to finning and abusive fishing.

You are the content and communication director of Alianza Tiburones Canarias. What is it? Why is it based on Canary Islands?

Advancing in my interest in elasmobranchs (sharks and rays), I was learning more about them, more I realized that in the Canary Islands there is a treasure: the angelshark (Squatina squatina), a shark belonging to one of the most threatened families from all sharks, whose species is declared by the IUCN as critically endangered, one step away from extinction.

angelote squatina squatina alianza tiburones canarias
Angelshark (Squatina squatina) (Picture: Ricardo R. Fernández).

The Alliance for the sharks of Canary Islands is an association of people concerned about the Canary marine environment, and especially elasmobranchs that live there, and in particular the state of conservation of angelshark.

At present, we have not yet managed to stop the fishing of angelshark, despite being prohibited and the level of critical threat to the species, but at least we got from the Canary Government an “educational” measure. We believe that tourists who hire the services of these companies do not know that capturing an angelshark contributes to their extinction (although freeing it after suffering serious damage), or that is forbidden. Therefore, it is mandatory that these companies clearly exhibit a sign with elasmobranchs which can not be fished.

Our association is not interested in confronting these companies, but to collaborate with them in educational tasks.

Which is the mission of the Alliance?

The “vision”, as a long-term goal, of our association is to make the Canary Islands a dive’s paradise with elasmobranchs. Over the short term, our “mission” is the promotion, dissemination and the environmental education and conservation of the Canary marine biodiversity, with special emphasis on elasmobranchs.

Therefore, my colleagues in the Canaries and the team of Madrid are dedicated to change the bad image of sharks, and to participate in everything related to their protection.

Which activities do you do for shark conservation?

Canary Islands is precisely where we do most of the activities. My companions who live there are constantly moving throughout the islands, giving educational talks in schools, universities, fishermen’s associations, diver forums participating in fairs biodiversity, solidarity markets … A massive outreach and education focused particularly in younger people, which we believe is slowly paying off.

Through social networks, we receive a lot of information about shark sightings by divers. Our Facebook page shows every week pictures of angelsharks and other elasmobranchs, done by divers, who give us details of the spotted animal: its size, sex, depth of sighting, place (not published to avoid poachers), and other data relevant to the statistical study we are doing.

Now that we know a little more about the Alliance, I would like to know if there are so many species of sharks and rays in Spanish waters, since most people think we do not have these animals on our shores.

Spain has many kilometers of coastline, both Mediterranean and Atlantic. Both the Mediterranean Sea and the Atlantic are home to many species of sharks. So, we must eradicate that idea. About the number of species, some reports expose that in the Mediterranean Sea there are 90 species of sharks. And the Atlantic Ocean is home to many more.

I think divers know that there are sharks in all seas and oceans, but it is very rare to meet anyone, especially because they detect us before we do. And because each time there are fewer, due to overfishing and finning.

Ninety species in the Mediterranean are a lot … What role do sharks play in marine ecosystems?

There are over 500 species of sharks worldwide, with varied shapes, sizes, lifestyles …, so in general it cannot be generalized for the whole group what we are goint to say. We have the largest of all fishes, the whale shark, which feeds on plankton, and conversely, small sharks as predators that work at its level.

Overall, sharks are apex predators that are at the top of the food chain. Therefore, they play an important role in the ocean ecosystem, maintaining ecological balance. In general, they act as scavengers helping to eliminate dead animals, thus preventing the spreading of disease and strengthening the genetic makeup of prey populations. As predators, they help to maintain the levels of individuals in the lower level of the marine food chain.

Red trófica marina, en la que vemos que el tiburón está en la parte superior de ésta (Imagen: Transformación del Entorno).
Marine food chain, in which we can observe sharks at the top (Picture: Transformación del Entorno).

Despite their importance, I am sure that they are threatened. Which are their main threats?

The biggest threats, according to FAO, are overfishing and finning.

For those who do not know the term finning, I must say that shark fins are very valuable (about 20 €/kg), much more than meat (between 1 and 2 € per kg). The reason is that shark fins are an ingredient in a traditional dish, the shark fin soup, a deli, which can cost almost 100€ each soup. The rapid growth of the middle class in China has caused the price of kilo to increase in the international market. So, ships prefer to store more fins than meat. Therefore, shark fins are cut and the dying animal is returned to the water; as shown in this video:

This macabre activity is prohibited in many parts of the world, but not in all places. In the European Union, it has been banned since 2003, but the regulation was adopted allowing certain unloading of fins with a permit. The fleets of Spain and Portugal, European fishing powers, used this exception in the law, supported by the Spanish and Portuguese governments.

Is this exception still being used to unload fins without their body?

A few years ago, there was an European movement to eliminate the exception of this law, and numerous conservation organizations and governments in many European countries banded together to approve the measure of “fins attached”, ie, when fishing a shark, fishermen cannot disembark body and fins separately. This is a measure that has been very successful in order to eradicate finning in many areas of the world. The new European antifinning law was passed in 2012 and came into force in 2013, with the measure of “fins attached” applicable to international EU waters and all European vessels worldwide.

This does not mean that catch sharks is illegal, and even sell their fins in a global market that is very opaque and generates many benefits to many countries, among which is ours.

Which role does Spain play?

In Spain, many sharks are caught, and the most fished species is undoubtedly the blue shark. The Port of Vigo, the largest fishing harbour in Europe, is the only one in which fishing statistics are published each year, detailing the species. By 2014, nearly 10,000 tons of sharks of all kinds were unloaded. The shark meat in Galicia, called Quenlla or Caella, is being increased its consumption, mainly by the campaign that the big fishing companies are doing. And it is very easy to see that the blue shark is sold fresh or frozen in the main Spanish supermarkets.

Seeing everything, I image that sharks are not very protected. Is that right?

Unfortunately, in Spain and in the rest of the world, the level of protection of sharks is very low.

The oceans are unfortunately an area ​very unprotected. Maybe it is because much of its surface has no owner, so-called international waters.

In Spain, and in Europe, there are a number of species for which it is forbidden, not only its fishing, but even upload them to the ship to remove the hooks and return them to the sea. That is the case of angelshark, the bigeye thresher, the hammerhead, the basking shark, the white, the porbeagle and some rays.

Since last year, there have been protected new shark species in Spain, but only in the area of ​​the Mediterranean: the school shark, the shortfin mako shark and the porbeagle, and several species of rays, such as the guitar fish. This means that if we find school shark in a menu from a bar, it is only illegal if it has been caught in the Mediterranean, but we will never know, as consumers, if the animal comes from the Atlantic or the Mediterranean. The best thing in this case is not to eat.

So, is there some illegal product? 

Shark fins are not illegal in our country if they come from unprotected species, such as blue shark.

At the international level, it is only prohibited trade with hammers’ fins, whale shark‘s fins, white’s fins, porbeagle’s fins, basking shark’s fins and longimanus’s fins (and some rays). This is the real drama: the fin market is not illegal, but for many of us is immoral.

There is an international movement called Fin Free, in which some cities have added, and in them the sale and consumption of fins is not allowed.

I do understand; is really complicated everything. Moving on… We have all seen plenty of movies in which the shark is bad, the murderer. Is it reality or fiction?

It is quite true that cinema has done much harm to the conservation of sharks since all, until you begin to learn things, have experienced fear even in the same word shark.

entrevista tiburones alianza canarias
There are so many movies in which sharks are the murder (Picture: Misterios).

However, more and more divers dive with them and have no problems. There are many ways to dive with sharks and only a group of more aggressive by nature species are subject to special precautions, such as the white, the tiger or the bull sharks. What is clear is that we are not on their menu.

Accidents with these animals, although of great importance on media are very few compared to those who die, for example, against attacks of hippos and crocodiles.

Given its importance and degree of threat, what can society do to save these species?

The truth is that a lot. The simple fact of knowing the situation helps a lot, because what happens is that the general population, and even governments, are unaware of many of the things we have talked today. Certainly, greater awareness and public pressure are the best weapons to get governments to act.

Moreover, do not buy the products we have mentioned and be part of all the opportunities for citizen participation in law-making as possible. Antifinning current law is the result of pressure from many European conservation groups, which could be heard and through which regulatory initiatives were established.

Thank you very much for your time. I’m sure our readers will appreciate all this knowledge that you have given us.

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Large sharks that eat plankton

Baleen whales are known to be the biggest animals on Earth that feed on plankton, but they are not the only big animals that eat these tiny organisms. In this post, you will discover three species of shark that consume plankton. 

WHAT IS PLANKTON?

Plankton refers to those tiny organisms that drift in the water with the currents. They can be classified as phytoplankton, which include the planktonic algae and other autotrophs or producers that may be the most important producers in many marine ecosystems, or as zooplankton, which include the heterotrophic plankton (the primary consumers). There are so many groups of organisms that spend all their life in the plankton, but other may be present just in some phases.

Organisms included in the zooplankton (Picture: Sci-news).
Organisms included in the zooplankton (Picture: Sci-news).

So many marine groups of animals feed on plankton, but baleen whales are known to be among the biggest animals that eat these small creatures. Some sharks are known to eat these little organisms: the famous Whale shark (Rhincodon typus), the awesome Basking shark (Cetorhinus maximus) and the stunning Megamouth shark (Megachasma pelagios). Did you know about these three species of planktophagous sharks? 

THE BIGGEST FISH IN THE WORLD

The biggest fish in the world usually is 12 meters long (but may achieve a length of 15 meters), weights 22 tonnes and its mouth is so wide that could swallow a car. We are referring to the famous whale shark (Rhincodon typus).

Whale sharks are true sharks, so they breathe using gills and are cold-blooded fishes. The reason of their name is the fact that they feed on plankton in a similar way of whales: they swim slowly (1,5-5 km per hour) with the mouth opened (which has dense filter screens) and swallow the small organisms present in the water, like coral and teleost spawn, krill, copepods, jellyfishes, small cephalopods and schooling fishes. They are also reported to feed almost vertically in the water. They can be identified so easily for their colossal size and for their dark blue colouration with white spots all over the body.

The whale shark is the biggest fish in the world (Picture: Mauricio Handler).
The whale shark (Rhincodon typus) is the biggest fish in the world (Picture: Mauricio Handler).

Little is known about the biology of these big animals. They live usually alone in coastal, pelagic and oceanic waters of the tropics and warm temperate zones, except the Mediterranean sea. They migrate extremely large distances. Every spring, they migrate to the continental shelf of the central west coast of Australia.

Due to direct and indirect fishing, their populations have reduced and the IUCN classifies them as a vulnerable species. Nowadays, their fishing is widely forbidden. Do you know that swimming with whale sharks has a negative impact on their populations? 

THE BASKING SHARK

The world’s second largest fish is also a filter feeder and is also a shark: it is the basking shark (Cetorhinus maximus). This shark lives in coastal and pelagic of temperate and boreal waters, but is a migratory species.

They can be distinguished from other sharks for their big mouth, small teeth and long gill slits. They are solitary animals, but sometimes they can form a small group of animals. Basking sharks consume small fish, fish eggs and zooplankton. They capture them on their gill rakers with the help of mucus secreted in the pharynx. In average, they swim at 3,7 km per hour. So, how many tonnes of water filter per hour? 

The basking shark (Cetorhinus maximus) is the second biggest fish in the world (Picture: FLMNH).
The basking shark (Cetorhinus maximus) is the second biggest fish in the world (Picture: FLMNH).

Their conservation status is vulnerable, but is considered to be endangered in the North Pacific and the Northeast Atlantic subpopulations. The fact that their fins are among the most valuable in international trade explains their conservation status. Moreover, accidental fishing is a threat to consider.   In some regions, such us European Union, they are protected by law.

THE MEGAMOUTH SHARK

The megamouth shark (Megachasma pelagios) is a large oceanic shark (at least 5 metres long) with long pectoral fins, but sometimes is littoral on the continental shelves. They live in tropical and subtropical waters. Little is known about this species because it was discovered in 1976.

The megamouth shark (Megachasma pelagios) is a strange planktophagous shark (Picture: ).
The megamouth shark (Megachasma pelagios) is a strange planktophagous shark (Picture: Theethogram).
Its low-flow filter apparatus suggest it is less active than the whale and basking sharks. Megamouth might swim slowly with its jaws wide open to capture their preys by suction. A surprising feature of this shark is its bioluminescent mouth, which acts to attract prey. Its conservation status is unknown, but accidental fishing might be a threat.

REFERENCES

  • Camhi, MD; Pikitch, EK & Babcock, EA (2008). Sharks of the Open Ocean: Biology, Fisheries & Conservation. Blackwell Publishing.
  • Carrier, JC; Musick, JA & Heithaus, MR (2010). Sharks and their relatives II: Biodiversity, adaptive physiology and conservation. CRC Press.
  • Castro, P & Huber ME (2003). Marine biology. The McGraw-Hill (4 ed).
  • Fundación Squalus (2011). Guía para la identificación de especies del Programa de avistamiento de tiburones y rayas de la Reserva de Biosfera SEAFLOWER.
  • IUCN: Cetorhinus maximus 
  • IUCN: Megachasma pelagios
  • IUCN: Rhincodon typus
  • National Geographic: Whale sharks 
  • Oceana (2008). Guía de los Elasmobranquios de Europa.

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