Shark Depredation and Unwanted Bycatch in Pelagic Longline

Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries
Table A6.1. Landings in metric tons from the elasmobranch fishery in Peru from 1990-1999 (in Cattarci, 2004).
Species 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999
Rays 4311 2081 2771 3632 1658 1841 1126 1177 1477 1790
Smoothounds 6458 2705 8578 8747 3431 4125 3230 3166 8038 448
Sharks 768 525 2087 1212 548 694 1506 1915 4335 2043
Total 11537 5311 13436 13591 5637 6660 5862 6258 13850 18131
A6.2. Artisanal Longline Fleet Characteristics
Longline fishing was reintroduced in Peru in the late 1980s (Reyes,
1989) due in part to the collapse of traditional fisheries for boney fish
(Bonfil, 1996; Cattarci, 2004) and the search for new fishing techniques.
By the 1990s this fishing method had expanded, especially in Peru’s
southern ports (Escudero, 1997; Castejon pers comm.). During the
past decade the longline fishery has increased significantly. The
main target species are mahi mahi Coryphaena hippurus during the
austral summer and sharks, especially blue sharks Prionace glauca,
mako sharks Isurus oxyrinchus and hammerhead sharks Sphyrna
zygaena, from autumn to spring.
Artisanal fisheries are defined according to Peruvian fisheries
regulations as containing boats with a maximum of 32.6 m3 of storage
capacity, 15 m in length, and principally based on the use of manual
work during fishing operations (Ley General de Pesca, 2001).
By the 1990’s there were an estimated 190 longline vessels in Peru
(Jahncke et al., 2001). More recent information estimated that
approximately 1500 longline vessels operate during the mahi mahi
season (IMARPE, unpublished data).
Peru’s artisanal fleet is very large and diverse. Artisanal fisheries
contain mainly wooden vessels. A 1997 study of the fishery indicated
that there were more than 28,000 fishermen and 6,200 vessels
operating out of 109 ports (Escudero, 1997). One of the main fishing
methods employed is longlines. Statistics from IMARPE indicate that
1,968 longline trips were recorded for the second half of the year 1999
(Estrella et al., 2000). More recent information on artisanal longlines
indicates that in 2002, 11,316 trips were conducted (IMARPE,
unpublished data). This suggests substantial growth in the longline
fishery since 1999.
While there is much variation in longline fishing methods throughout
the country, some general characterizations can be made (Fig. A6.2,
Table A6.2). Longline vessels typically set their gear in the morning
and recover it in the early evening. Gear is set at the surface. Mainline
length varies by boat and number of hooks but is typically about
3-4 km. in length (See Fig. A6.2). The main target species include
Fig. A6.2.
Typical gear design of a Peruvian pelagic longline.
sharks and mahi mahi. Sharks are fished from approximately March
to November and mahi mahi are fished from December to February.
Trip length varies by season with mahi mahi trips typically lasting
5-7 days and shark trips lasting 15-20 days. Vessels may travel up to
250 miles from shore. Hook size and type varies but almost all vessels
use J hooks. Northern ports tend to use smaller hooks than in the
south. Species used for bait include giant squid, mackerel, and flying
fish. Bait may be fresh, frozen or salted. Weighted branchlines are used
in some ports, and are used more often in the south of the country.
Steel leaders are often used during shark season to reduce gear loss.
There are very few restrictions on the operation of artisanal vessels.
There are no quotas on the number of vessels, number of vessels
per owner, or on the longline gear itself. Monitoring of landings is
conducted by the Ministry of Fisheries and by IMARPE. Monitoring
is done in terms of metric tons of specimens landed. Only the
commercial species are monitored. Vessel departure permits and
security controls are managed by the Peruvian Navy - Direccion de
Capitanias y Puertos (DICAPI).
A6.3. Range of Fishing Gear and Methods
Table A6.3 summarizes the general fishing methods and gear
deployment strategies for the longline fleet in the ports where
surveys were conducted - Paita, Salaverry and Ilo. It should be noted,
however, that fishing methods and gear deployment vary somewhat
from port to port and vessel to vessel.
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