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

Risk analysis and evaluation
STOCK: Rattails – family Macrouridae
Severity/likelihood risk analysis:
Generic objective 1: Risk to maintaining the potential of the stock to meet the
reasonably foreseeable needs of future generations.
Analysis:
Reported catch data for the last five fishing years shows that large catches of rattails are taken annually. Catch is
dominated by FMA 3 with large catch also taken in FMAs 4 – 7. There appears to be a decreasing trend in
rattail catches with catch reported against the RAT code declining by 42 % over the last 5 years. At least some
of the decrease in rattail catch is attributable to decreases in the TACC of hoki and orange roughy stocks over
this period.
From 2002/03 to 2005/06 about three quarters of the rattail catch was landed with the remainder discarded. The
percentage discarded increased to close to 50% in the most recent fishing year. Of the rattail landed the amount
landed green has been steadily increasing and now accounts for close to 50%. There is some evidence that the
larger rattails may be processed as they reportedly provide good edible fillets. However it is unclear what
fraction of the catch of these species is reported against the species code rather than the generic RAT code.
There is no evidence that a target fishery is operating for any of the rattail species.
Little is known about the biology and life history characteristics of rattails and, given the predominant use of the
generic RAT code, it is difficult to determine whether catches of individual species are sustainable. It is known
that some rattail species are long-lived, which raises some concern. However, this is balanced against the
widespread and locally abundant distribution typical of rattail species. Rattails have been a consistent
component in the bycatch of New Zealand’s middle-depth and deepwater trawl fisheries since their inception
and remain well represented in catches across a broad range of fisheries.
Severity of impact (low, medium or high) : Low
Likelihood of impact (low, medium or high) : Low
Risk score (1-9) : 2
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