Turtles in Canary Islands

by | Jul 1, 2016 | 0 comments

One of the great exponents of Macaronesian culture and zoogeography are turtles in Canary islands. Macaronesia is a geographical region that includes five archipelagos, which are: the Azores, Madeira, Cape Verde and Canary Islands.

Sea turtles are exceptionally long-lived animals that are present in all ocean basins of the world. Their presence in the Canary Islands is constant due to the strategic location of the archipelago. The Canary Islands are located in the descending branch of the Gulf Stream which is a major highway of wildlife for those animals that use ocean currents as main means of transport.

The general and simplified life cycle of turtles that can be found in Canarian waters is as follows:

turtles in Canary islands .Migration map

(fig 1. Numerical representation of the phases of the general scheme of the life cycle of a sea turtle present in the Canary Islands).

  1. HATCHING eggs in the breeding areas
  2. NEWBORN Turtle are driven by the Gulf Stream
  3. JUVENILE turtles (oceanic habitat and/or neritic, that is to say, close to coast)
  4. Sexual MATURITY and displacement to the breeding area
  5. COPULATION > egg laying
  6. Displacement to FEEDING HABITATS (OCEANIC OR NERiTIC)

           7. a) females remain in feeding habitats 2- 3 years, the time to breed again.

            7. b) males can be back every year for reproduction.

Note: In this graph only the american origin of the turtle populations, as a simplification, is contemplated. There are also breeding spots for several species in Mexico, Cabo Verde, Guinea Bissau, and other several Central American countries etc.

Most common sea turtles spotted in Tenerife

The loggerhead turtle (Caretta caretta) is common throughout the Macaronesia in their juvenile stage pre adult, in all archipelagoes but in Cape Verde. The reason why individuals listed there are no juvenile is because it is an important breeding area for adults.

It seems that their migratory routes respect a latitudinal pattern, which means that individuals who were born in areas more northerly will migrate to a position homologous to the east. Individuals born in Florida are more abundant in Azores than in the Canary Islands and those born in Mexico are less frequent in Azores and more in Canary Islands (Monzón-Argüello et al. 2009).

turtles in Canary islands. Loggerhead turtle. Atlantic Eco Experience
turtles in Canary islands. Loggerhead turtle. Atlantic Eco Experience

The genetic differences between populations arriving in the Canaries and arriving in Andalusia are only patent in large individuals with good swimming ability, able to actively search for an appropriate site for food. Smaller animals with lower swimming capacity reach their areas more passively carried by currents.

The loggerhead is not a very filopatric species, that is to say, no great fidelity to the feeding areas. The growth and alimentation phase may happens in open ocean until about 10 years old feeding on jellyfish and salps Bolten, A. (2003). Upon reaching sexual maturity they move to feed close to their breeding places.

The category for conservation by administrations is:

-International Union for Conservation of Nature and Natural Resources (IUCN): Vulnerable.

-Spanish Catalogue of Treatened Species (CEEA): Vulnerable.

-Spanish Catalogue of Treatened Species (CCEA): Vulnerable.

Green turtle (Chelonia mydas): It is less common than the loggerhead turtle, but because of their life cycle and philopatry is a highly visible species.

Like other sea turtles show a very oceanic first phase wich lasts between 3-5 years but then violently change their diet and lifestyle and some approaches coast being very loyal to the chosen place to spend their pre maturity feeding primarily on algae.

When choosing coast areas around there is much interaction between animals and tourists who engage in scuba diving or snorkeling. It is common to see illegal activities related to turtles. The practice of feeding is explicitly prohibited and can cause to the turtles severe metabolic disorders and high levels of cholesterol and triglycerides in the blood.

turtles in Canary islands. Green turtle. Atlantic Eco Experience
turtles in Canary islands. Green turtle. Atlantic Eco Experience

A genetic study conducted by ADS Biodiversidad (www.adsbiodiversidad.org) suggests that green turtles coming to the Canaries come from many different places both the African coast and Central America.

The category for conservation by administrations is:

-International Union for Conservation of Nature and Natural Resources (IUCN): Vulnerable.

-Spanish Catalogue of Treatened Species (CEEA): Special Protection Regulation.

-Spanish Catalogue of Treatened Species (CCEA): Special Protection Regulation.

The leatherback turtle (Dermochelys coriacea) is present in all archipelagos. The most striking feature of their life cycle is that leatherback turtles does not present neritic phase, that is to say, feeding phase near the coast. It is an oceanic species in all its stages. In the Canary Islands it is very casual and constant presence.

turtles in Canary islands. Leatherback turtle. Atlantic Eco Experience

Free Access Image. @wikicommons

The category for conservation by administrations is:

-International Union for Conservation of Nature and Natural Resources (IUCN): Vulnerable.

-Spanish Catalogue of Treatened Species (CEEA): Special Protection Regulation.

-Spanish Catalogue of Treatened Species (CCEA): Special Protection Regulation.

Other species of turtles cited but much less presence such as the hawksbill turtle (Eretmochelys imbricata), Kemp’s ridley (Lepidochelys kempii) and olive ridley (Lepidochelys olivacea).

Conservation Problems

Some so fascinating animals that have managed to travel thousands of kilometers by swimming between continents flooded our curiosity with unanswered questions about their behavior, their migratory routes, their role in the ecosystem…

The possibility to answer all these questions is under serious threat due to human activities. The degradation of habitats turtles use for food as seagrass meadows, accumulation of garbage that are often mistaken for jellyfish, accidental entanglement in derelict fishing gear … all these are scenarios that we encounter every week at sea.

turtles in Canary islands. Atlantic Eco Experience
turtles in Canary islands Conservation. Atlantic Eco Experience

All public and private institutions must act in concert to minimize these effects and increase surveillance in ecosystems where it is well known that is hurting resident turtles on shore, massive tours that harass turtles or feed them. In most cases green turtles are fed with fish, when in proximity to coast phase feeds almost exclusively on algae. This causes serious metabolic disorders in turtles.

Our individual responsibility as citizens makes us responsible for the legacy we leave to future generations. Therefore let us not allow that kind of action in our presence.

For more interesting information about turtles see:

http://www.iucnredlist.org/

López-Jurado LF, Mateo JA (1997). Conservation status of reptiles in the Canary Islands.
Bonn Zool. Beitr., 36, 585-606.

Monzón-Argüello C, et al. (2009) Journal of Experimental Marine Biology and Ecology 373 (2009) 79–86.

Reich KJ, Bjorndal KA, Bolten AB (2007). The “lost years” of green turtles: using stable
isotopes to study cryptic lifestages. Biology Letters, 3, 712-714.

Varo-Cruz N, Hawkes LA, Cejudo D, López P, Coyne MS, Godley BJ, López-Jurado LF
(2013). Satellite tracking derived insights into migration and foraging strategies of male
loggerhead turtles in the eastern Atlantic. Journal of Experimental Marine Biology and
Ecology, 443, 134-140.

turtles in Canary islands Conservation. Atlantic Eco Experience

Video rescate de tourtuga boba enmallada

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