Aquatic Environment and Biodiversity Annual Review 2012

AEBAR 2012: Non-protected bycatch
6.3.9. Tuna longline fishery
The New Zealand tuna longline fishery was dominated by the foreign licensed vessels during the
1980s, but is now comprised of chartered Japanese vessels and New Zealand domestic vessels. The
domestic fishing fleet has been the dominant fleet in the fishery since 1993–94 (Figure 6.20).
Number of hooks (millions)
30.0
25.0
20.0
15.0
10.0
5.0
0.0
1979-80
1980-81
1981-82
1982-83
1983-84
1984-85
1985-86
1986-87
1987-88
1988-89
1989-90
1990-91
1991-92
1992-93
1993-94
1994-95
1995-96
1996-97
Fishing year
1997-98
1998-99
1999-00
2000-01
2001-02
2002-03
N.Z. Domestic
Foreign + charter
2003-04
2004-05
2005-06
2006-07
2007-08
2008-09
Figure 6.20: Effort (hooks set) in the tuna longline fishery. Black bars are Foreign and Charter vessels,
white bars are NZ domestic vessels.
The Japanese charter fleet mainly target southern bluefin tuna off the west coast South island (WCSI),
and domestic vessels target mainly southern bluefin tuna and bigeye tuna and the fishery is
concentrated on the east coast of the North Island (ECNI) with some fishing for southern Bluefin tuna
on the WCSI.
The most recent analysis of fish bycatch in tuna longline fisheries was the 2006−07 to 2009−10
fishing years (Griggs & Baird 1012)
Observer effort has mainly focused on the Japanese charter vessels (all vessels covered and usually
about 80% of hooks observed), with lower coverage of the domestic fishery (approximately 7-8%
during 2006−07 to 2009−10). Most of the fishing effort is carried out by the domestic fleet so this
fleet is under-observed.
During 2006−07 to 2009–10, 111 074 fish and invertebrates from at least 62 species or species groups
were observed. Most species were rarely observed, with only 37 species (or species groups) exceeding
100 observations between 1988–89 and 2009–10. The most commonly observed species over all years
were blue shark, albacore tuna, and Ray’s bream, these three making up nearly 70% of the catch by
numbers. Blue shark and Ray’s bream were the most abundant and second most abundant species in
each of the four fishing years 2006–07 to 2009−10 (Table 6.2). Other important non-target species
were albacore, lancetfish, bigscale pomfret, dealfish, porbeagle shark, swordfish, moonfish, mako
shark, deepwater dogfish, sunfish, and oilfish. The catch composition varied with fleet and area
fished.
QMS bycatch species are blue sharks, mako sharks, porbeagle sharks, school shark, moonfish, Ray’s
bream, and swordfish. Swordfish is also sometimes targeted.
152
2009-10