usually sited on the back edge of the flipper with the closure system facing upward to
avoid abrasion to the body of the animal (Camiñas and Valeiras 2008).
The conventional tagging of marine turtles in the Alboran and western Mediterranean Sea has mainly been conducted on loggerheads, after their capture as bycatch
on fishing gear or after their recovery from a range of injuries in recovery centres. It
is very difficult to estimate the population size of any marine turtle population
because only female turtles return to their home beaches for breeding after reaching
sexual maturity (males never return to their natal beaches). Researchers mainly use
the number of nets or number of females reproducing per year as a proxy of
population size (Margaritoulis et al., 2003; Ceriani et al. 2019). This part of the
population and its trend are then compared to those of previous years.
Sea turtle tagging began in the IEO Oceanographic Centre of Malaga in the
1980s. Jumbo Rototags were used initially, but these were soon discarded because
most of the captured turtles were juvenile and the tags were too large. Subsequently,
different metallic tags were used, such as the Monel 400 (Nickel International,
USA). These tags were supplied in different sizes with their applicators by the
Archie Carr Centre (ACCSTR) (University of Florida, Gainesville, USA). The
ACCSTR coordinates a programme for distributing turtle tags, managing tagging
data, and facilitating the exchange of tagging information. The tags carry an identification number and the address of the university.
From 1999 to 2001, the same type of metal tag (manufactured in Europe) was
used by the IEO to participate in the European Marine Turtle Project (EMTP).
Another type of metal tag was donated by the General Directorate of Nature
Conservation of the Spanish Ministry of the Environment within the framework of
an Agreement between this Ministry, the Spanish Herpetological Association
(AHE), and the IEO (Roca 1997; Roca and Camiñas 2000). These tags are smaller
than those described and carry a serial number and the inscription “ICONA MINIST,
AGRICULT, E-28005 MADRID, SPAIN”. Tagging was conducted on board recreational vessels and fishing boats and in recovery centres.
Some of the turtles tagged within the IEO tagging programme in the western
Mediterranean (1986–2018) were recaptured in the following areas: the Algerian and
Tunisian coasts, the area south of the Balearic Islands, the Spanish Atlantic and
Mediterranean coasts, and the coasts of Cuba, Florida, and Nicaragua.
Most of the tagged turtles were recaptured in the usual fishing zones of the
Spanish longline fleet near the southern Balearic Islands in the year following their
tagging or in subsequent years. This result is suggestive of an annual reiterative
process of trophic migration to the Balearic Sea.
The use of satellite radiometry has led to advances in the study of migration in
reptiles and other wild species. The IEO has participated in different projects that
have used satellite transmitters. These devices have increased our understanding of
the causes of marine turtle migration, the relationship between migration and habitat
use by different marine turtle species, and species’ adaptation to different environmental conditions (e.g. temperature, currents, depth, and diurnal eating or resting
periods). Currently, all commercially available satellite tags function through the
ARGOS system.
21 Marine Megafauna and Charismatic Vertebrate Species
731
avoid abrasion to the body of the animal (Camiñas and Valeiras 2008).
The conventional tagging of marine turtles in the Alboran and western Mediterranean Sea has mainly been conducted on loggerheads, after their capture as bycatch
on fishing gear or after their recovery from a range of injuries in recovery centres. It
is very difficult to estimate the population size of any marine turtle population
because only female turtles return to their home beaches for breeding after reaching
sexual maturity (males never return to their natal beaches). Researchers mainly use
the number of nets or number of females reproducing per year as a proxy of
population size (Margaritoulis et al., 2003; Ceriani et al. 2019). This part of the
population and its trend are then compared to those of previous years.
Sea turtle tagging began in the IEO Oceanographic Centre of Malaga in the
1980s. Jumbo Rototags were used initially, but these were soon discarded because
most of the captured turtles were juvenile and the tags were too large. Subsequently,
different metallic tags were used, such as the Monel 400 (Nickel International,
USA). These tags were supplied in different sizes with their applicators by the
Archie Carr Centre (ACCSTR) (University of Florida, Gainesville, USA). The
ACCSTR coordinates a programme for distributing turtle tags, managing tagging
data, and facilitating the exchange of tagging information. The tags carry an identification number and the address of the university.
From 1999 to 2001, the same type of metal tag (manufactured in Europe) was
used by the IEO to participate in the European Marine Turtle Project (EMTP).
Another type of metal tag was donated by the General Directorate of Nature
Conservation of the Spanish Ministry of the Environment within the framework of
an Agreement between this Ministry, the Spanish Herpetological Association
(AHE), and the IEO (Roca 1997; Roca and Camiñas 2000). These tags are smaller
than those described and carry a serial number and the inscription “ICONA MINIST,
AGRICULT, E-28005 MADRID, SPAIN”. Tagging was conducted on board recreational vessels and fishing boats and in recovery centres.
Some of the turtles tagged within the IEO tagging programme in the western
Mediterranean (1986–2018) were recaptured in the following areas: the Algerian and
Tunisian coasts, the area south of the Balearic Islands, the Spanish Atlantic and
Mediterranean coasts, and the coasts of Cuba, Florida, and Nicaragua.
Most of the tagged turtles were recaptured in the usual fishing zones of the
Spanish longline fleet near the southern Balearic Islands in the year following their
tagging or in subsequent years. This result is suggestive of an annual reiterative
process of trophic migration to the Balearic Sea.
The use of satellite radiometry has led to advances in the study of migration in
reptiles and other wild species. The IEO has participated in different projects that
have used satellite transmitters. These devices have increased our understanding of
the causes of marine turtle migration, the relationship between migration and habitat
use by different marine turtle species, and species’ adaptation to different environmental conditions (e.g. temperature, currents, depth, and diurnal eating or resting
periods). Currently, all commercially available satellite tags function through the
ARGOS system.
21 Marine Megafauna and Charismatic Vertebrate Species
731