Reduction
of the impact produced by sea lions on the fisheries in Mexico
M. O. Maravilla-Ch?vez1, S. Hern?ndez-V?zquez2,
A. Zavala-Gonz?lez3 and A. Ortega-Rubio2
1Instituto
Nacional de Ecolog?a, Programa de Investigaci?n de los Mam?feros Marinos,
Ocampo 1045. Centro, C.P. 23000.
La Paz, B. C. S., Maxico, 2Centro de Investigaciones Biol?gicas
del Noroeste, S. C. Mar Bermejo 195, Col. Playa Palo de Santa Rita,
C.P. 23090 La Paz,
B. C. S., Maxico, 3Direcci?n de la Reserva de la Biosfera islas del Golfo,
Ensenada, B. C.
(Received: 28 January, 2005 ; Accepted: 5 December, 2005)
Abstract:
Activities of fishermen in the Bay of La
Paz, B. C. S. are focused to satisfy the local demand of fish
and shellfish by using ??approximately 300 small outboard crafts
equipped with gillnets.Sea lions in this Bay attack
the fishes captured damaging both product and gear. We did experimental gillnet
throws? to
determine?? the frequency and preferences
of sea lions in fishing areas. 52 experimental gillnet throws with time averages
of 2 hr were performed, rending? an average? of 30 kg of fish captured and less than 10%
of damages to the net.. Traditional fishermen in this Bay usually? left the net the whole night, (approximately
7.50 hr, obtaining an average of 50 kg of captured fish, but the? damages to the nets is in average of 40%. The
cost-benefit balance comparing? our
alternative fishing? method,? which includes the
use of the gillnets during the afternoon, watching for sea lions and retiring
the nets at their arrival, it is more sustainable and profitable than? the traditional fishing method currently used
by the local fishermen. This paper suggests how to minimize the harmful effects
of the sea lions on the fishermen productivity and gear, maximizing the
production and reducing the damage. Our alternative method is applicable to
other regions where this harmful interaction is taking place. We conclude that
the coexistence of sea lions?fisheries is feasible, by applying the simple
measures that we propose.
Key words: Sea
lions, Fisheries interaction, Gillnet, Maximum production, Minimum damage.
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