Shark Depredation and Unwanted Bycatch in Pelagic Longline

Peru Artisanal Mahimahi And Shark Longline Fishery
The catch of rays with pelagic longlines is small. Species from the
genus Milyobatis spp. (eagle ray) and other species such as skates
from the genus Psammobatis spp. are captured but have no significant
commercial value and are usually discarded.
A6.6. Shark Market and Implications for the
Management Framework
The shortage of traditional bony fish (Vannuccini, 1999), the
reintroduction of the longline as a fishing method (Reyes, 1989,
Castejon pers comm.), and the market for shark fins as ‘added
value’ to the commerce of the sharks, have combined to promote the
development of a targeted shark fishery by Peru’s artisanal longline
fishermen.
During the 1990’s, at least 70% of shark production went to the
domestic market as fresh chilled product (Vanuccini, 1999). Exports of
shark fins have increased from $2.5 million in 1995, to approximately
$7.5 million in 2000 (PROMPEX Peru, 2006). The main markets for
Peruvian shark fins are Hong Kong and Japan (Table A6.8) 1 .
Still, the domestic market for fresh meat drives the industry more
than the fin price. The higher trading price for fresh-chilled meat
compared with other products demonstrates that the domestic
market absorbs most of the shark landings. Inland towns also offer a
market for dried, salted shark meat (Vannuccini, 1999).
The export market for frozen shark meat has grown. From 2000 to
2005 exports of shark meat tripled (Table A6.9). During this same
period, however, revenue from these exports only increased by 150%.
In the 1990’s shark meat was exported mainly to Spain (Vanuccini,
1999). More recently, the main export markets include Uruguay,
Spain, Brazil and Colombia (see table 9; PROMPEX Peru, 2006). No
information is available on the shark species exported.
The local market price for shark fins in Peru is around $10/kilo
fresh. The price for meat is about $0.9 to $1.85 per kilogram (Ilo fish
market, May 2006). While shark fins have a higher value per kilogram
than shark meat in the international market (Catarci, 2004), on an
individual animal basis more money is earned by a fishing trip from
the meat than the fins.
A6.7. Economic, Social and Ecological Effects,
Including Effects on Fishing Practices, from
Regulations Governing Shark Interactions
From the forty-two fishermen interviewed, 16 were based in Paita,
10 in Salaverry and 16 in Ilo. Almost all (93%) interviewed fishermen
report that they always retain sharks during the mahi mahi season.
Regularly, blue and mako sharks are caught and the whole body and
fins are retained. The whole crew and boat owner receive the revenue
from the sale of fins and meat. In some cases, this money is used to
cover expenses such as gas and food. Meat of blue sharks is sold for
approximately $0.5-1.3/kilo and makos for $0.9-2.8/kilo. Revenue
from fins ranges up to $16 per kilo. Mako fins are more valuable than
those from blue sharks.
Only three (7%) respondents replied that income from sharks has
changed over the years. Two replied that in the past revenue from
fins was retained by the owner only. One respondent indicated that
revenue from sharks in the past was not as much as currently.
Revenue from the sale of jaws is retained by the members of the crew
that clean them. One fisherman reported earning $2-30 for selling
jaws for decoration or for artisanal crafts. Other shark parts such as
the “verija” (pelvic fins) are given to the fishmongers as payment for
services. These products are later commercialized.
Regulations on minimum size of capture for sharks are not taken
into consideration by most fishermen mainly because there is no
enforcement by the government and because fishermen are not aware
of them. Those fishermen (4.8%) who reported that they were aware
of the regulations stated that they still retain sharks under minimum
size of capture.
For most of the fishermen interviewed, revenue from catching sharks
exceeds the costs associated with shark depredation and loss and
damage to gear (average damage cost estimate per mahi mahi set
was $11). Most fishermen reported changing their fishing methods
and gear during the mahi mahi season. These changes included using
nylon monofilament leaders, using giant squid for bait, setting hooks
shallower than during shark season and fishing in areas closer to shore.
These gear changes reduce shark captures, but the purpose of the gear
changes is to optimize mahi catch, and not to reduce shark catch.
Fishing for mahi mahi during summer is more profitable because
fishing areas are closer to shore and the amounts of mahi mahi are
considerable higher than during the shark season. As a result, fishing
trips are shorter and expenses (food and gas) are reduced.
A6.8. Practices to Deal with Caught Sharks and
Costs from Shark Depredation and Gear Damage
Most longline vessels use an 80-100 cm nylon monofilament at
the end of the branch line, located between the baited hook and a
weighted or non-weighted swivel. Some fishermen use a mix of wire
leaders and nylon monofilament depending on the time of year. Wire
leaders are often used during shark season or toward the end of mahi
mahi season when there is a higher chance of catching sharks.
As a result, respondents reported that about three quarters (82%)
of sharks that bite baited hooks in mahi mahi gear bite through the
monofilament line and are not retained on the line to be hauled to
the vessel. Some respondents were not sure whether gear loss was due
to sharks or manta rays. Ninety-two percent of respondents stated
that during the mahi mahi season, vessels catch an average of 2.1
sharks on a typical set.
1
All prices are given in U.S. dollars unless otherwise indicated.
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