I am pleased to
report that we were able to capture the first professional images of
endangered Spiny Angelsharks (Squatina guggenheim) in Mar Del
The spiny angelshark aka angular or hidden angelshark has a very small range
within the coastal waters of southern Brazil, Uruguay and northern
Argentina. Fisheries harvesting angelsharks within that region lump
this species with two other angelsharks: S.occulta and S.argentina.
Collectively, the IUCN has designated all three angelsharks as
ENDANGERED because of either directed fisheries (mostly in
Brazil) or bycatch (thoughout their entire range).
Details of the
threat assessment by the IUCN:
The nocturnal habits
of angel sharks render them vulnerable to bottom gillnets. Increases
in captures during the 1990s are attributed to the introduction of
this gear on the shelf and slope off southern Brazil at that time.
Gillnets were reported as six times more effective at catching angel
sharks than trawling alone (Vooren and Klippel 2005).
Gravid females of S. guggenheim have been observed to abort embryos
easily upon capture, further reducing the reproductive capacity (Vooren
and Klippel 2005). A low rate of dispersal between populations also
makes them especially prone to local depletion and means that
recolonisation will be extremely low.
Fishery landing statistics of "angel shark" in southern Brazil refer
to S. guggenheim, S. occulta and S. argentina combined. The term
"angel shark" in the present assessment refers to this assemblage of
species. These three species occur on the continental shelf with S.
argentina also occurring on the upper slope. Annual catches of angel
shark from the continental shelf peaked at about 2,000t in 1986-1989
and again in 1993, and then decreased to 900 t in 2003. Angel shark
CPUE by otter trawl and pair trawl on the continental shelf
decreased by about 85% from 1984 to 2002 (Miranda and Vooren 2003,
CEPERG 2003, GEP/CTTMar 2003, Vooren and Klippel 2005). While S.
occulta and S. argentina have been significant bycatch species in
the trawl and gillnet fishery for monkfish Lophius gastrophysus at
the shelf edge and uppermost slope, S.guggenheim occurs shallower
than that fishery.
Additionally, an angel shark bottom gillnet fishery on the outer
shelf commenced around 1990 and at present large amounts of angel
shark are caught this way (Miranda and Vooren 2003). Research trawl
surveys of the outer shelf in the years 1986/87 and 2001/02
confirmed that in southern Brazil the abundance of S. guggenheim has
decreased to 15% of its original level and this is attributed to
recruitment overfishing primarily due to the bottom gillnet fishery
(Vooren and Lamónaca 2002, Vooren and Klippel 2005).
In Argentina, the shark bycatch from gillnet and bottom trawl fleets
targeting species such as school shark, croakers and flatfishes is
poorly known. However, in 1973, Cousseau estimated Squatina as 6% of
the total weight of the catches of the coastal bottom trawling
fleet. The predominant size in these catches was about 70 to 80 cm
TL; small sizes (25 to 45 cm TL) were uncommon. Cousseau (1973),
based on García Cabrejos and Malaret (1969) calculated the total
landings of angel shark in Mar del Plata harbour in 1964 to be 1,074
MT and 2,355 MT in 1965. Otero et al. (1982) considered the angel
sharks to be species with a low concentration on the Buenos Aires
coast, with an annual biomass for 1981/2 estimated at 4,050 tons.
However, in 1991 as much as 4,167 MT were taken, and 4,281 MT in
1996. Chiaramonte (1998) stated that the angel sharks were the
second most important fish landed by the gillnet fleet of Puerto
Quequen. Total captures of angel sharks in Argentina oscillated
around 1,000 MT between 1979 and 1984 then increased to maximums of
over 4,000 MT in the 1990s. Catches consist almost entirely of S.
guggenheim. Peaks were reached in 1997 and 1998, before landings
dropped in 2002 to 2,000 MT, rising again in 2003 to 3,550 MT (Massa
et al. 2004). Thus there has been an overall negative trend in
landings during the period 1998-2003 (Massa et al. 2004).
Furthermore, Vooren and Klippel (2005) (citing Massa and Hozbor
2003) suggested a 58% decline in the CPUE of angel shark in the
coastal bottom trawl fleet.
In Uruguay there is little direct fishing for angel sharks, but they
are taken as bycatch in industrial and artisanal fisheries. The
estimated capture has been 300 to 400 MT per year since 1997. There
are no statistics by species, but largest captures probably
correspond to S. guggenheim and S. argentina (A. Domingo pers. comm).'
Citation: Chiaramonte, G. & Vooren, C.M. 2007. Squatina guggenheim.
The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>.
Our partner on this expedition
was Juan Carlos Mattioli; a commercial diver and diving instructor
from Mar Del Plata on the northeast coast of Argentina.
Juan has been diving in the region for many years and has seen a
decline in shark numbers first hand. The problem as he explains it,
is the huge fleet of fishing boats that drop nets and long-lines on
the offshore banks; the most productive fishing grounds within easy range of
the fleet and a critical habitat for the dwindling angel sharks.
Fishermen in Argentina are not allowed to
target angel sharks directly but the sharks regularly become
entangled in their nets. The safest way to remove a thrashing shark
is to bludgeon it first and even if they release it responsibly, many
sharks are either dead upon arrival or they are so badly mangled
and/or stressed that they die after release.
Juan would like to see the area completely closed to fishing but
support for shark conservation initiatives in Argentina is difficult
to generate; especially when conservation proposals impact local
Although it is a daunting task
to take on the commercial fishing industry, Marine Protected Areas
are a vital component in any conservation efforts being developed
for non-migratory species. Juan is actively looking for a
conservation partner in the international community with experience
in the creation of MPAs.