标题：The influence of depth, venting and hook
type on catch and release angling mortality of
snapper, Pagrus auratus (sparidae): implications for
management
期刊名称：Western Australia. Fisheries Department. Fisheries Research Reports
印刷版ISSN：1035-4549
出版年度：2009
卷号：191
页码：25-25
出版社：Government of Western Australia / Department of Fisheries
摘要：Cages were used to investigate the mortality after catch and release angling of snapper Pagrus
auratus (Family Sparidae), a recreationally and commercially important demersal species
found throughout temperate coastal and shelf waters of Australia. Overall, 65.4% of the
604 snapper caged in the experiment survived release. Depth of capture was by far the most
important factor affecting release mortality. Mortality increased from an average of 3.42% of
fish caught in the shallows (5, 15 and 30 m) to 69.0% of fish from the deeper waters (45 and 65
m). Due to the practicalities of catching and caging fish while working at sea it was necessary
to mix fish of different sizes in cages and to have different quantities of fish in cages. However,
while there was increased mortality associated with increased quantities of fish in cages, this
did not affect the result of increased mortality with depth. Venting, hook pattern, hook location,
number of days caged, size of fish (TL in cm) and swimming at release did not affect mortality
significantly. Although mortality in gut-hooked fish was almost three times (91.7%) that of
mouth-hooked fish (33.6%), the proportion of gut-hooked fish in the total catch was small (1%
of circle hooks and 3% of J hooks).
The clear depth stratification in rates of mortality of snapper indicates that Legal Minimum
Length (LML) and or bag limits are suitable management regulations for shallow coastal
areas, but that their usefulness decreases at deeper offshore locations. This bodes well for
the management of snapper dwelling in the numerous shallow bays, sounds and gulfs around
Australia that have well defined boundaries suitable for defining separate management zones.
In contrast, deeper offshore fisheries need to consider management strategies that include
alternatives to size and bag limits, and would certainly need to include estimates of post-release
mortality when attempting to manage a fishery through controlling total fishing mortality.
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