Kyne & Simpfendorfer.. - Shark Specialist Group

abilities to sustain fishing or rebound from population declines. While such an observation is
not a surprise, it does provide the ability to predict, within the bounds of confidence intervals,
the rebound potentials of species for which only the maximum depth of occurrence is known.
There is a general lack of available trade and landings data for deepwater chondrichthyans.
Many deepwater species are taken as bycatch, often discarded, or landed under generic
species-codes such as 'shark' or 'other'. The lack of accurate catch data, including the underreporting
of catches, the lack of recording bycatch, poor taxonomic resolution and speciesidentification,
and illegal fishing, makes an assessment of the global catch of deepwater
chondrichthyans extremely difficult. Production statistics from FAO fisheries databases were
analysed to overview trends in global and regional production. From 1950 to 2004 there was
an increasing but fluctuating trend in global production of deepwater chondrichthyans. The
global trend was largely influenced by the trends in production figures from the Eastern and
Western Atlantic. However, poor data resolution and under-reporting make this analysis of
questionable accuracy.
Where data or information are available, intensive fishing has led to the collapse of deepwater
squaloid dogfish stocks, particularly Centrophorus species. In Australia, fishing has depleted
upper slope species, with 98–99% declines for Centrophorus species over a twenty-year
period. Additionally, severe declines have been documented for other species. One
chondrichthyan, Squalus megalops, increased in abundance (small, abundant species probably
recruiting from the shelf to the slope and benefiting from declines in other species). Recent
management arrangements will benefit the conversation of mid-slope species, but pressure is
continuing on the upper slope.
In the Northeast Atlantic, less than 20 years of fishing in deep water to the west of the British
Isles has led to the depletion of Centrophorus squamosus and Centroscymnus coelolepis
stocks, prompting calls for a zero catch limit for these species. Even with such a regulation in
place, bycatch will remain an issue for these species. In the Azores, the poor market value of
shark liver oil led to the end of directed fishing for the kitefin shark Dalatias licha, but a
considerable biomass decline from nearly 30 years of fishing pressure is apparent for the
stock. A cessation of fishing suggests that the stock will likely begin to recover, but the
overall result appears to suggest local depletion of the population. A liver oil fishery for
gulper shark (Centrophorus species) in the Maldives was short-lived, commencing in 1980
and closing just over 20 years later due to population depletion. The present status of the
stock is unknown, but fishing for gulper sharks has ceased. The resource was probably fished
beyond sustainable levels in its early years.
In contrast to the above examples, Namibia is taking a precautionary approach to the
development of deepwater shark fisheries. Short-term fishing rights were granted to explore
the deepwater shark resource but no commercial licences have yet been granted due to
inadequate biomass data to accurately set catch limits.
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