Information briefs and risk analyses for species under consideration ...

Habitat interactions
6 No information is available.
Associated species (bycatch and target)
7 Seal shark is taken as bycatch in a large number of fisheries targeting QMS species. A
limited amount of target fishing also occurs.
Environmental conditions
8 No information is available.
Protected species interactions
9 None known.
Stock Assessment
10 There are no estimates of current or reference biomass, or sustainable yield.
However, like other deepwater shark and dogfish species it may not be able to
withstand high exploitation rates due to low productivity and fecundity.
11 In a review of the distribution and abundance of deepwater sharks in New Zealand 1 ,
the only relative biomass estimates for seal shark were derived from two trawl surveys
on the Chatham Rise in 2001, resulting in estimates from 103 to 289 tonnes. Analysis
of trawl survey and catch per unit effort (CPUE) data from 1989-90 through 1998-99
indicated an increase in seal shark relative abundance in depths greater than 800m on
the Chatham Rise, although the changes may represent better catch reporting rather
than changes in abundance. Other regions in New Zealand waters were not reviewed.
Social, Economic, Cultural Information
Commercial fishery characteristics 2
12 Due to its widespread geographic distribution, seal shark has been reported as bycatch
in 37 target fisheries over the last five fishing years. For the fishing years 2002/03 –
2006/07 total EEZ reported catch of seal shark was 3,125 tonnes. Note that this figure
and those in the following tables only relate to catch or landings reported against the
BSH code. Seal shark may also be reported against generic codes (e.g. OSD – other
sharks and dogfish or DWD – deepwater dogfish). Seal shark may also be confused
with Lucifer dogfish and reported against the code ETL. There may be further
confusion between the code for seal shark (BSH) and the code for basking shark
(BSK) leading to under-reporting of seal shark.
13 The following table summarises the total reported catch distribution by FMA for the
fishing years 2002/03 – 2006/07.
FMA1 FMA2 FMA3 FMA4 FMA5 FMA6 FMA7 FMA8 FMA9 FMA10
61 t 278 t 1,254 t 708 t 238 t 282 t 295 t 1 t 9 t 0 t
1
Blackwell, R.G.; Stevenson, M.L. (2003) Review of the distribution and abundance of deepwater sharks in
New Zealand waters. New Zealand Fisheries Assessment Report 2003/40. 48 p.
2
Tables showing figures as percentages may not sum to 100% as percentages are rounded to the nearest whole
number.
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