Juan Fernandez Islands (Chile) Living Marine Resources and Fishery

121 Pages·2007·4.45 MB·English

Juan Fernandez Islands (Chile)
Living Marine Resources and Fishery Perspective
Marine Resource Management Program
School of Oceanography
Oregon State University
in partial fulfillment of
the requirements for the
degree of
INDEX
- Acknowledgements
- Introduction
- General information about the islands
- Oceanographic conditions of the region
- Present fishery
- Discussion
- Appendix
1.- List of known species found
around Juan Fernandez Islands
2.- Research program proposed to
execute in the islands
3.- Robinson Crusoe's story
- Bibliography
ACKNOWLEDGEM=TS
I take pleasure at this time in acknowledging
the hel p given to me by several people. Specifically, I
must say thanks to Mrs. Amelia Nishik.,-TP, Mrs. Maxine
Hilfiker, Miss Anne Hoch'oerg and Mr. Rocco Falotico who
helped me put this paper closer to ShakeE peare's lang-uage.
special atteton has been given to the
aeoently,
studies dealing with marine species. This is due principally
,' also to
to the scarce knowledge that we have about them 2n
the fishing interest generated by the relative abundance of
• some of them.
.carried out in Chile.
At the present, the studies
fishery
to research biological and
primly
have been conducted
coastal organisms.a the other
r
problems associated. with nea
af
hand, studies on the oceanic species, since they are not
fected by exploitation have been delayed, and the inform,ation
actually available is limited.
y years •
few species have been ext)olted for man
A
South-St
A n the
around several Chilean islands
In the particular case of the Juan Fernandez islands, the 1Drin-
the "lobster of Juan Fernandez"
deal fisheries are related to
big demersal fish called "bacalao
and to a
(Jasus frontalis)
(ectoria(olvorion) oxigaa2ios).
Or Qal mcn de roca"
for their history
also fs-TeUS
Those islands
of theme 50otti3h sailor lived
on one
and..principally.because
solitary and. voluntary con-
years and four months in
for four
1 Lefoe wrote his book "Ho-
Danie
fineent (1704-1709). Later,
the story became rapidly known
Cru,;oe" throu gh which
binson
is officially cal-
f the islands
lfT, one
around the world. so
led '-'_obinson Crusoe and the other � rinero 3- 11k.ir'k in honor
vyte_vi.
2 1
of the oricinal maroon (sea Appendix 3 i .� the flora and
fauna of these islands are of extraordinary scientific inte-
rest. It is imoortant to study the o� the islands and
the relationship of its flora and fauna with organisms from other
biogeographical regions.
Also important to consider � the hu-nan inter-
vention on the islands since their d i scoy ery in 15T4,. t lest
one s pecies of the authoctonic flora was extLnlished ("Sanda-
lo" or "ber g amot mint") and the Juan Fernandez fur seal (r-
cto'ohoca (Arctoce phalus) philiop ii) was considered for a lon
time extinct, due to the cruel and uncontrolled huntin g by
American sailors, during the XVIII and All centuries.
All these characteristics motivated the Centro
de Investig. aciones del Mar (OIMAH) of the Catholic University
of Valparaiso (Chile) to begin, in. 1971, , a research program.
This research was focused. on the oceanographic conditions of
this re g ion and the fishing activity wh:i:chhich is at pres ent the
principal occupation of the population on the islands. The
results of these studies have stimulated the scientific inte-
rest of this oceanic region.
This pacer is en attempt to summarize our actual
Knowledge about the marine resources available in the area.
it also analizes the situation of the fishery and the princi-
-nal as pects involved. in a possible Plan for an in e..;-ral
ries develor,ment of the Oceanic re .;7ion around the islands.
This r)lan could maintain the� tradition of artisanal fishery
by considering their unique characteristics.
GENEd..::L INFOTTOM ABOUT THE SLIITJS
The Juan Fernandez Islands are located at 330
40' S and approximately 360 miles from the South _Lmerican
continent (79° 81 0 W). This group of islands include obin-
son Crusoe I. (formerly called ias a Tierra, with 93 2 and
950 m as maximun height); Santa Clara I. (3 2,2 and 375 m ;
and several small barren islands (El ierduo, El 'lludo, Los
Chamelos, and Juanango). Ninety� miles west of these is-
lands there is another island, iarnero Selkirk (form4ly mas
Afuera, 82 Km2 and 1835 m height).
Accordinyto BRUGGEN ( 1950), the nature of this
grout of islands is volcanic, formed probably cParing the. ,J
per Tertiary by the to p of airlolder ride 7,Thich -,as separated
from the continent, between ikrauco and M gallanes. urinx the
Oligocene, this ridge descended underwater and the islands were
formed by later eruptions.
The Juan Fernandez rid.:_=,-e is ori f -ri+- ecL�perpendi-
cular to the Chilean coast and is � miles lon (Figure 1).
The tops of, some mountains are very close to the surface. Lenths
of only 300 to 400 meters have been found on some of them, This
is the case of the O'Higgins Sea mount, only 40 miles west of
Val paraiso. The islands constitute the emerged seamount peaks
of this ridge.
LAJ:i.AZAGI and "- SACKS (1976) pointed out that there
is a remarkable correlation between the location of the oceanic
Juan Fernandez ridge and the transition from the Chilean flat
seismic zone (between about lat 27° and 33° s) to the steeper
seismic zone in southern Chile. They said also that active vol-
canoes are located on the Juan Fernandez ridge. So the ridge
intersects the Chilean coastline near lat 33° 5, where the
coastline has a major bend and where the Feru-Chile trench
becomes increasingly sediment filled.i ,ioreover, the inland pro-
jection of the ridge beneath the South American Plate closely
coincides with the northern limit of the active volcanoes of
Southern Chile as well as with the end of the Central Valley
of Chile. In this case, the authors suggest that the Juan Fer-
nandez ridge forms a ?one of weakness in the Nazca plate along
which the plate tears as it descends beneath the South Ameri-
can plate (Figure 2).
Regarding the Presence of Juan Fernandez ridge
in this area, some s pecific research was carried out during
the Expeditions idarchile VIII, IX and X. The princi pal objecti-
ves of this research were to increase our knowledge about its
bathymetry, the influence of the ridge in the eneral oceano-
graphic conditions and what kind of living resources are pre-
sent.
During the expedition i,jarchile IX, three fishing
stations with bottom longlines and tra ps were carried. out on
the top of the seamount East of the Juan Fernandez Islands. A
fouth station was established. on U'digginSeamount. The sampled
de pths were between 267 m and 470 m. The catch was composed of
four species of the Telestomi class: "bacal ao (Hectoria
(Polv prion) oxi geneios), Conger s p ., Gilbertia s p . and. Mora
pacifica, and three species of Elasmobranchii class: Etmos-
terus sp., EtmosteruS granulosus and Somniosus s p . Catch rates
were between 29.5 and 35.4 fish per 100 hooks (CEHDA, 1977)
The traps caught principally "jaibas rdgantes"
(red crab), Geryon duinauedens, but the results of this fishing
survey still have not been published- However, the research
proved that Gn the ridge there are no lobsters present due
nerhams to the greater depth.
around. 450 miles north of t_t__e Juan iiernande7
lands exist another Froup of islads ramed. the DesventuradaS
Islands. This other grou p , 400 miles from t � chilec.n coast,
is forted by the SP:o Pelix and Sar limbrosio islands-both with
very difficult access and without water - plus the small barren
islands Gonzalez and the Cathedral of i:eterborough. These is-
lands are uninhabited, -but sometimes fishermen from the Juan
Fernandez Islands come to fish for "bacalao and lobsters
which are in great abundance and usually bigger than in the
other group of islands. This is due to the scarce fishing ac-,.
tivity in this area and the problems of establishing a fishing
base in these islands.
The region where the islands are located is charac-
terized by a subtrocical climate. In this area, rains are common
in all the seasons (Table I). among the meteorological parame-
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Figure 2. Geological features of the South East Pacific, showing the Juan
Fernandez ridge.