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

Risk analysis and evaluation
STOCK: Silver Dory (Cyttus novaezealandiae)
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 fishing years 2002/03 – 2006/07 indicates that catch varied between approximately
1,034 tonnes in 2004-05 and 484 tonnes in the most recent fishing year. It is uncertain what led to the large
decrease in catch over the last two fishing years. Silver dory is taken as bycatch in at least 30 fisheries that
target QMS species and the decline might reflect overall decreased effort in associated target fisheries. The
catch of jack mackerel (the principle target fishery in which silver dory is taken) has also decreased over the last
two fishing years although whether this is due to reduced effort is unclear. The decline in silver dory take may
also be due to natural annual variation in silver dory stocks, changes to the spatial distribution of effort in target
fisheries taking silver dory as bycatch, or a fishing-related cause that affects silver dory stock abundance.
Nothing is known regarding reproduction, recruitment, or habitat interactions of silver dory. Given the highly
variable reported catch, the level of risk to silver dory stocks is difficult to assess although decreases in catch
over the last two years provide some cause for concern.
Severity of impact (low, medium or high) : Medium
Likelihood of impact (low, medium or high) : Low
Risk score (1-9) : 3
Generic objective 2: Risk to avoiding, remedying or mitigating any adverse effects of
fishing on the aquatic environment.
Analysis:
The risk of adverse effects on the aquatic environment from catch of silver dory under an open access
management regime is low due to the fact that there is no target fishery for the species. Some catches of silver
dory are taken by bottom trawl, but only as a consequence of a target fishery for QMS species.
Nothing is known of the habitat interactions or of the marine ecosystem role of silver dory but due to its
widespread habitat, it has some function in the marine ecosystem.
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