373
the information gathered subsidized diving expeditions for 40 different areas, where
samples of Goliath Grouper and other Epinephelidae species were found, demonstrating that these areas are in fact potential aggregations sites. The indications from
the combination of traditional knowledge and the diving expeditions provided
enough support for new field efforts to be continued.
It is important to highlight that a great part of the present interest from government and researchers in spawning aggregations are due the deleterious effects fishing has brought to the main marine fish resources. Additionally, the effects in the
exploration and production of oil and gas industry has forced the responsible
Environmental Agencies to better understand the dynamics of these spawning
aggregations events, and to propose more adequate management plans, in order to
guarantee the sustainability of both resources and traditional populations.
14.3.2 Photo-Identification
Photo-identification (photo-iD) is a widely utilized approach on a variety of marine
species including marine mammals, sea turtles and cartilaginous fish, providing a
single non-invasive mark-recapture technique, which is critical for threatened species such as the Goliath Grouper Epinephelus itajara.
Being the largest grouper in the Atlantic Ocean (>2 m total length - TL, > 400
Kg) (Bullock et al. 1992), Goliath Grouper have a series of characteristics, which
turn them a potential species to work with photo-iD. They are sedentary, have a high
degree of site fidelity – performing yearly spawning migrations and aggregations
(Eklund and Schull 2001; Pina-Amargós and Gonzáles-Sansón 2009; Leite et al.
2012) – and have spots and blotches that are unique for each individual. Adults
inhabit both natural and artificial reefs, generally in depths less than 50 m (Bullock
et al. 1992), within the recreational dive limits (i.e., 40 m), and juveniles are often
observed in mangrove areas, considered their nursery grounds.
Investigations on habitat use and abundance of Goliath Grouper in Brazil from a
participative survey – which engaged volunteer divers in data-collection (see Giglio
et al. 2014b) – provided the first clues to focus efforts on photo-iD research.
Our first investigations (Giglio et al. 2014a) started with a small but intriguing set
of images, where scars were used to photo-identify three Goliath Grouper, photographed and re-sighted several times at their home sites along the Brazilian coast,
including the longest report for site fidelity, in more than 4 years.
Since 17% of the sightings in the participatory survey (Giglio et al. 2014b), came
from Fernando de Noronha Archipelago, a National Marine Park, our efforts were
directed to this offshore archipelago.
Fernando de Noronha is located 186 nm off northeastern Brazil (03°50′ S, 32°25′
W), and is under the influence of the northern branch of the South Equatorial
Current. The leeward seascape is mainly composed of descending slopes with large
scattered boulders and patch reefs, whereas the windward side of the archipelago is
characterized by extensive algal-vermetid ridges along rocky shorelines (Maida and
Ferreira 1997).
14 The Atlantic Goliath Grouper: Conservation Strategies for a Critically Endangered…
the information gathered subsidized diving expeditions for 40 different areas, where
samples of Goliath Grouper and other Epinephelidae species were found, demonstrating that these areas are in fact potential aggregations sites. The indications from
the combination of traditional knowledge and the diving expeditions provided
enough support for new field efforts to be continued.
It is important to highlight that a great part of the present interest from government and researchers in spawning aggregations are due the deleterious effects fishing has brought to the main marine fish resources. Additionally, the effects in the
exploration and production of oil and gas industry has forced the responsible
Environmental Agencies to better understand the dynamics of these spawning
aggregations events, and to propose more adequate management plans, in order to
guarantee the sustainability of both resources and traditional populations.
14.3.2 Photo-Identification
Photo-identification (photo-iD) is a widely utilized approach on a variety of marine
species including marine mammals, sea turtles and cartilaginous fish, providing a
single non-invasive mark-recapture technique, which is critical for threatened species such as the Goliath Grouper Epinephelus itajara.
Being the largest grouper in the Atlantic Ocean (>2 m total length - TL, > 400
Kg) (Bullock et al. 1992), Goliath Grouper have a series of characteristics, which
turn them a potential species to work with photo-iD. They are sedentary, have a high
degree of site fidelity – performing yearly spawning migrations and aggregations
(Eklund and Schull 2001; Pina-Amargós and Gonzáles-Sansón 2009; Leite et al.
2012) – and have spots and blotches that are unique for each individual. Adults
inhabit both natural and artificial reefs, generally in depths less than 50 m (Bullock
et al. 1992), within the recreational dive limits (i.e., 40 m), and juveniles are often
observed in mangrove areas, considered their nursery grounds.
Investigations on habitat use and abundance of Goliath Grouper in Brazil from a
participative survey – which engaged volunteer divers in data-collection (see Giglio
et al. 2014b) – provided the first clues to focus efforts on photo-iD research.
Our first investigations (Giglio et al. 2014a) started with a small but intriguing set
of images, where scars were used to photo-identify three Goliath Grouper, photographed and re-sighted several times at their home sites along the Brazilian coast,
including the longest report for site fidelity, in more than 4 years.
Since 17% of the sightings in the participatory survey (Giglio et al. 2014b), came
from Fernando de Noronha Archipelago, a National Marine Park, our efforts were
directed to this offshore archipelago.
Fernando de Noronha is located 186 nm off northeastern Brazil (03°50′ S, 32°25′
W), and is under the influence of the northern branch of the South Equatorial
Current. The leeward seascape is mainly composed of descending slopes with large
scattered boulders and patch reefs, whereas the windward side of the archipelago is
characterized by extensive algal-vermetid ridges along rocky shorelines (Maida and
Ferreira 1997).
14 The Atlantic Goliath Grouper: Conservation Strategies for a Critically Endangered…