All about the canary islands: Canary Islands | Geography, Facts, & History
canary islands | All you need is Biology
BASIC BIOLOGICAL TERMS, BOTANY, ENGLISH, ENVIRONMENT, ENVIRONMENT: GENERAL, General
Laia Barres Gonzalez 1 comentari
Islands are natural laboratories where we can study evolution in vivo. Whether from volcanic or continental origin, the fact that islands being isolated from the mainland by the sea makes that island biota present spectacular adaptations, sometimes originating giant or dwarf species in comparison with their mainland relatives. In this article, we describe the evolutionary mechanisms behind this phenomenon and talk about some striking examples.
Islands can have a volcanic origin, involving the emergence of virgin lands that will be colonized involving new adaptations to the new conditions. Islands can also have a continental origin, involving the separation of the mainland by tectonic processes and isolation of fauna and flora before connected.
Volcanic conus aspect in Hawaii. Source: Steve Juverston, via Flickr.
EVOLUTION MECHANISMS ACTING IN ISLANDS
Generation of new species caused by the emergence of a geographic barrier, such as the emergence of a range, changes in sea level or emergence of new islands by tectonic movements is a process known as allopatric speciation and is the main process acting on islands. We can described two kinds of allopatric speciation:
- Vicariant speciation: when two populations are separated by a geographic barrier, for example when a piece of land separated from the mainland. An example is the island of Madagascar, that when separated from Africa left the biota of the island isolated from the continent by the sea.
- Peripatric speciation: a new population establishes and gets isolated in a new environment by a very small number of individuals from a larger population. This is the case of the colonization of a sterile land, such as oceanic islands. In this case, the individuals that colonize the new environment may not represent the genetic pool of the original population and with time and reproductive isolation; may originate a new species (founder effect).
The great British naturalist and creator of the theory of evolution, Charles Darwin, insipirated on their findings into the volcanic archipelago of the Galapagos to develop his great theory, paradigm of modern science.
Oceanic islands are formed by exploding volcanoes or movements of the mid-ocean ridge. Due to this volcanic activity, groups of islands are formed, each island having its own history, climate, topography and geology. This creates a perfect scenário to observe how evolution works because each population reaching a new island is affected by different environmental pressures and may never come in contact again with other islands populations, forming unique species, endemic to each island. Many naturalists and scientists have studied the evolution in vivo in volcanic origin archipelagos such as the Hawaiian Islands, Seychelles, Mascarene Islands, Juan Fernandez archipelago or Canary Islands. One of the last islands appeared in the Atlantic Ocean is the Suerty Island, emerged at 1963 30 km southwards of Iceland. Since then, life advent has been studied to understand ecological and evolutionary mechanisms acting in island colonization.
Suerty Island in eruption, in the south of Island. Source: Wikimedia.
ISLANDS ADAPTATIONS: GIGANTISM AND WOODINESS
Often oceanic islands, present no predators and this triggers the appearance of very curious adaptations. One of the most surprising processes is gigantism in animals or woodiness acquisition in plants.
Woodiness acquisition in islands by herbaceous plants on the continent has been documented in several families and islands around the world. The cause of this phenomenon would be the absence of herbivores and competitors in sterile islands, which would allow developing a greater height willing to reach sunlight.
For example, in Hawaii we found the alliance of the Hawaiian silverswords. It comprises 28 species in three genus (Argyroxiphium, Dubautia and Wilkesia), all woody members of the Asteraceae family or sunflowers. Their closest relatives are perennial herbs in North America.
Hawaiian silversword aspect from Argyroxiphium genus (left) and their closest relatives in mainland (right), from Raillardella genus. Source: Wikimedia.
In the Canary Islands, there are many examples of this phenomenon. Echium genus of Boraginaceae or borage and forget-me-not family contains about 60 species, of which 27 are located in different islands of volcanic origin in the Macaronesia (Canary Islands, Madeira and Cape Verde). Almost all members of this genus found in Macaronesia are bushes, forming an inflorescence that can reach up to three meters high, being the symbol of the Teide National Park (called tajinastes) while his nearby relatives are Eurasians herbs such as blueweed (Echium vulgare).
Echium wildpretii (left) in Tenerife and one of its closest relative from mainland (Echium vulgare) on the right. Source: Wikimedia.
Also in the Macaronesia, we find another example in the Euphorbiaceae family. Euphorbia mellifera, endemic to the Canary Islands and Madeira and E. stygiana endemic to Azores are endangered or critically endangered trees according to the IUCN, which can grow up to 15 meters high, being part of the laurisilva vegetation, a subtropical humid forest typical from Macaronesia. Their nearest relatives are Mediterranean herbaceous species.
Euphorbia mellifera in Maderia (left) and one of his closest relatives from the Mediterraneum basin (right, E. palustris). Source: left Laia Barres González and right Wikimedia.
In the animal kingdom, we also find peculiar adaptations. Herbivorous inhabiting islands usually have no predators or competitors, triggering appearance of larger species than in the mainland, where large carnivores avoid this characteristics incompatibles with hiding or escaping.
One of the most famous examples of island gigantism are the Galapagos giant tortoises (Chelonoidis nigra complex), including about 10 different species, many endemic to a single island of the archipelago. This turtles are the most long-lived and largest in the world. They can reach two meters in length and 450 kg in weight and can live more than 100 years.
Galapagos giant tourtle. Source: Wikipedia.
Also among the reptiles, there are the Gallotia giant lizards of the Canary Islands. There are several single island endemic species: G. auaritae in La Palma, believed extinct until the discovery of several individuals in 2007, G. bravoana in La Gomera, G. intermedia in Tenerife, G. simonyi in El Hierro and G. stehlini in Gran Canaria, among others. Among the giant lizards of the Canary Islands there is the extinct Gallotia goliath, reaching up to 1 m length and currently being included in the G. simony circumscription.
Gallotia stehlini in Gran Canaria. Source: El coleccionista de instantes Fotografía & Vídeo via Flickr.
Another example is Flores island in Indonesia, where we found a giant rat (Papagomys armandvillei) doubling the common rat in size. Interestingly, hominid fossils having experiences the contrary process were also found in this island, since it was dwarf primate compared to the Homo sapiens current size. It is Homo floresiensis, who was only 1 meter tall and weighed 25 kg. It became extinct about 50,000 years and coexisted with Homo sapiens.
Giant rat (Papagomys armandvillei) from Flores. Source: Wikimedia.
Dwarfism is another evolutionary process that may occur on islands caused by the lack of resources in some islands, compared to mainland.
Unfortunately, islands holds a peculiar and unique biota that is suffering from of exploitation and extinction. The islands conservation biology helps to understand and preserve this natural heritage so rich and unique.
Barahona, F.; Evans, S. E.; Mateo, J.A.; García-Márquez, M. & López-Jurado, L.F. 2000. Endemism, gigantism and extinction in island lizards: the genus Gallotia on the Canary Islands. Journal of Zoology 250: 373-388.
Böhle, U.R., Hilger, H.H. & Martin, W.F. 2001. Island colonization and evolution of the insular woody habit in Echium L. (Boraginaceae). Proceedings of the National Academy of Sciences 93: 11740-11745.
Carlquist, S.J. 1974. Island biology. New York: Columbia University Press.
Foster, J.B. 1964. The evolution of mammals on islands. Nature 202: 234–235.
Whittaker, R.J. & Fernández-Palacios, J.M. 2007. Island biogeography: ecology, evolution, and conservation, 2nd edn. Oxford University Press, Oxford.
alloptaric speciationcanary islandsdwarfsevolutionGalápagosgigantsHawaiiislandsspeciation
ENGLISH, General, INTERVIEWS
Marc Arenas Camps 2 comentaris
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 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.
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.
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.
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.
alianza tiburones canariasangelsharkblue sharkcanary islandsmónica alonsomónica alonso interviewshark finningshark protectionsquatina squatinawhale shark
CONTENTS, ENGLISH, ENVIRONMENT, MARINE ENVIRONMENT
Marc Arenas Camps 2 comentaris
Oh the occasion of the accident of the Russian fishing boat called Oleg Naydenov close to Grand Canary (Spain), the article of this week is about the effects of petroleum on marine environment. Here, I am going to talk about the origin of the petroleum in the sea, which are the transformations that suffer and the effects on marine fauna and flora.
The accident of the Russian fishing boat called Oleg Naydenov off of Grand Canary, which has finished with its sinking, is causing the appearance of oil in an area of 12 square km. The reason is that it sank with more than 1,400 tonnes of oil, 30 of diesel oil and 65 more of lubricant.
Despite oil tanker accidents have a huge impact in the media, they represent a small portion of the amount of hydrocarbons that get in the sea. In general terms, these are the main sources of petroleum in the sea:
- Industrial discharges and urban dredging: 37%.
- Boat’s operations: 33%.
- Oil tanker accidents: 12%.
- Atmosphere: 9%.
- Natural sources: 7%.
- Exploration and production of hydrocarbons: 2%.
Although this values can vary depending of the sources, in general they represent quite good the proportions. It has been estimated that, each year, are poured into the sea 3,800 millions of litres of hydrocarbon, equivalent to 1,500 Olympic pools.
When hydrocarbons are spilled into the sea (accidentally or deliberately), their features and shape change. This changes are physical, chemical and biological. This are the mechanisms:
- Evaporation: it allows that certain substances of the hydrocarbons go to the atmosphere, reducing about 40% its volume just in the first day. In any case, the surrounding atmosphere will be flammable.
- Dispersion: it consists on the fragmentation of the oil patch into small drops. When these drops are small enough, they remain in suspension and they mix with water and favours the biodegradation and sedimentation.
Oil dispersion is positive because it allows the biodegradation (Picture from Ecosfera)
- Emulsification: consists on the absorption of water so the hydrocarbon’s volume increases between 3 and 4 times. This hampers the oxidation and biodegradation.
- Solution: depending on the product’s composition, the water temperature and its agitation. Only the more volatile components can be dissolved.
- Oxidation: the effect of the oxidation can produce a compound that is easier or more difficult to degrade.
- Sedimentation: consists on the down vertical displacement of the hydrocarbon’s particles. Depending on its density (with respect to water), the size and the agitation of the sea.
- Biodegradation: consists on the elimination of hydrocarbons by living beings, like bacteria and fungus.
As we have said in the beginning of the post, the main goal of this is to comment which are the effects of petroleum (and other hydrocarbons) on marine fauna and flora. Let’s start!
The effects of petroleum on fauna are wide due to the high diversity of marine organisms. The main effects on the marine biodiversity are:
- Direct contamination: petroleum sticks on feathers, fur and scales, what make difficult the thermal isolation, movements and other important functions. As a consequence, this kills fishes, marine mammals and birds.
Marine mammals are effected by petroleum pollution (Picture from Channel Island)
- Modification of gas exchange: the petroleum sheet reduces the content of oxygen in the water, what produce the dead of the plankton and fishes, what produce the dead of the organisms that feed on them.
- Alteration of seafloor: when petroleum is placed over the seafloor kills and produce sublethal effects on benthonic flora and fauna.
- Intoxication: petroleum poisons marine fauna, soaking into its digestive system and its skin and mucosa. The result is, on the one hand, the dead for suffocation and genetic disruptions on fishes, molluscs, marine mammals, reptiles and birds; and, on the other hand, the intoxification of other organisms like humans when they feed on them.
Only a quarter part of the contaminated marine birds achieve the earth, the rest dead (Photo: Marine Photobank, Creative Commons).
- Increase of the infections: because petroleum produces a reduction of the resistance to infections. This is specially important in birds because when they clean the feathers theirself, they swallow petroleum, so they present sublethal concentrations.
- Negative effects on fertility, reproduction and propagation of fauna and flora.
- Modification of the behaviour.
- Destruction of food sources.
- Incorporation of cancerous substances on food webs.
- Effects on the availability of light: we cannot forget that the petroleum patch in the sea surface produce an important reduction of light in the water column. This causes a reduction or elimination of photosynthesis, essential process for the maintenance of food webs because the algae growth depends on light, which is consumed by herbivorous (and so on) and produce an oxygen input into the water. Moreover, we have to take in consideration that algae communities are shelter for many larvae and youthful fishes.
- Marine communities alteration: at community level, there is a gradient of vulnerability of oil spills. From less to more vulnerability, the communities are: exposed cliffs, exposed rock platforms, fine sand beaches, middle to big sand beaches, exposed tidal planes, big sand beaches, gravel beaches, protected rocky beaches, protected tidal planes, marshlands and mangroves, subtidal seafloors of sand and gravel, mud subtidal seafloors, batial and abyssal seafloors, infralittoral and circalittoral seafloors and reef corals.
- Notes of the subject Ecotoxicology and marine pollution of the Master in Oceanography and Marine Environment Management of the University of Barcelona.
- EmerCoast Coast. “Training on marine pollution risks. Environmental risks in the littoral and marine environments”.
- Course”Marine Pollution” from EuroInnova.