351 
Abstract— The protein fingerprints of 
shark fillets and fins taken from com- 
mercial landings in northern New Zea- 
land waters were compared with the 
protein fingerprints from control sam- 
ples of ten species of coastal sharks. 
Isoelectric focusing (IEF) in agarose 
gels revealed species-specific protein 
profiles in the ten control species. 
The fillets and fins were identified 
as school shark ( Galeorhinus galeus ), 
rig (Mustelus lenticulatus), hammer- 
head shark (Sphyrna zygaena), and 
bronze whaler ( Careharhinus brachy- 
urus). Around 40% of fillets from cartons 
labelled as lemon fish (M. lenticulatus) 
were from other species. Shark fins 
were identified from four species, two 
of which are prohibited target species 
in northern New Zealand. The large 
number of mislabelled shark products 
necessitates the use of a simple bio- 
chemical technique for identification 
of shark species in commercial shark 
products. With IEF, around 100 speci- 
mens can be identified by a laboratory 
technician each working day from small 
amounts (<0.5 g) of white muscle. 
Manuscript accepted 16 November 2000. 
Fish. Bull. 99:351-355 (2001). 
Biochemical identification of shark fins and fillets 
from the coastal fisheries in New Zealand 
Peter J. Smith 
Peter G. Benson 
National Institute of Water and Atmospheric Research Ltd 
301 Evans Bay Parade 
Wellington, New Zealand 
E-mail address (for P J. Smith): p.smith@mwa.cri,nz 
Several shark species are common in 
New Zealand coastal waters and form 
the basis of fisheries producing fillets 
for the domestic market and fins for 
the Asian market. Like most sharks, 
the New Zealand species are vulnera- 
ble to over exploitation owing to their 
slow growth rate, large size at maturity 
and low fecundity (Castro et al., 1999). 
Three shark species are currently man- 
aged under the New Zealand Quota 
Management System (QMS): school 
shark (Galeorhinus galeus), rig (Muste- 
lus lenticulatus), and the Callorhinchi- 
dae elephant fish (Callorhinchus milii) 
(Annala et al. 1 ). Quotas were intro- 
duced for these species in 1986 fol- 
lowing dramatic increases in catches. 
Two species, G. galeus and M. lenticula- 
tus, are caught in set-net fisheries that 
target coastal sharks, and since the 
introduction of the QMS, the fisheries 
have stabilized at around 5000 tons per 
annum (Annala et al. 1 ). A competitive 
quota has been established for spiny 
dogfish (Squalus acanthias), but other 
species of shark, either because of low 
abundance or assumed low value, have 
been excluded from the QMS. Some 
of these shark species, such as bronze 
whaler ( Carcharin us brachyurus), ham- 
merhead shark (Sphyrna zygaena ), and 
blue shark (Prionace glauca ), are taken 
as bycatch in other fisheries but are 
prohibited as target species. 
The shark species in the New Zea- 
land coastal fisheries are large, and 
whole fish are readily identified by ex- 
ternal characteristics. However most 
sharks are processed at sea: specimens 
are “trunked” — the head, guts, and fins 
are removed — and the product chilled 
or frozen. Further processing may take 
place on land and the product is sold as 
either trunks or fillets and fins. It is dif- 
ficult to identify fillets and fins to the 
species level and landed catches may 
include several species. Management 
and enforcement of multispecies shark 
fisheries require that landed products 
can be correctly identified to the spe- 
cies level. Thus a robust test is needed 
that will allow identification of fillets 
and fins. 
Several molecular genetic methods 
have been applied to fisheries-related 
taxonomic problems to identify and dis- 
tinguish closely related species. Allo- 
zymes have been the primary tool for 
taxonomic problems in fishes (e.g. Day- 
ton et al., 1994; Lacson and Bassler, 
1992) and have revealed cryptic species 
in teleosts (e.g. Lacson, 1994; Smith et 
al., 1996). More sophisticated and ex- 
pensive molecular methods, based on 
DNA extraction, followed by sequenc- 
ing or restriction enzyme digestion, are 
increasingly used for similar identifi- 
cation problems (Bartlett and David- 
son 1992), including shark species (e.g. 
Martin, 1993; Heist and Gold, 1998). 
Isoelectric focusing (IEF) of muscle pro- 
teins has been the preferred method 
for identification of teleost fillets and 
products (Lundstrom, 1980; Rehbein, 
1990); the method is used in legal cas- 
es to identify mislabeled fish products. 
Polyacrylamide IEF (Lundstrom, 1977, 
1980) has been adopted by the U.S. 
Food and Drug Administration for iden- 
1 Annala, J. H., K. J. Sullivan, C. J. O’Brien, 
and S .D. Ibal 1 . 1998. Report from the 
Fishery Assessment Plenary, May 1998: 
stock assessments and yield estimates, 
409 p. Unpublished report held in NIWA 
Library, 301 Evans Bay Parade, Welling- 
ton, New Zealand. 
