Mj. Keough et Gp. Quinn, Legislative vs. practical protection of an intertidal shoreline in southeastern Australia, ECOL APPL, 10(3), 2000, pp. 871-881
Harvesting of intertidal biota is a concern in many areas of the world. Whi
le the published literature is focused on reports of strong impacts of subs
istence harvesting, recreational collection of biota can also have a strong
effect. In either case, the management of these impacts is a major concern
and is most often done by complete or partial closures of sections of coas
tline. This management method may require ongoing intervention, in the form
of policing, education, or construction of barriers, and it is important t
o identify the effectiveness of these actions. We have previously shown tha
t physical closure of a section of rocky coastline in southeastern Australi
a resulted in increased mean sizes of a range of intertidal molluscs collec
ted for food and bait. The shoreline in question had legislative protection
and mechanical barriers, and we present data that demonstrate that the mec
hanical barrier was a critical component. Removal of barriers resulted in c
hanges in mean sizes and abundance of some gastropods over a period of 5 yr
. The two most heavily harvested species, Turbo undulatus and Cellana tramo
serica, showed reductions in mean size of similar to 15%, relative to nearb
y areas that had been exploited for many years, while two less harvested sp
ecies, Austrocochlea constricta and Nerita atramentosa, showed no changes f
ollowing opening of the former protected areas. Three control (i.e., nonhar
vested) species, Bembicium nanum, Lepsiella vinosa, and Cominella eburnea,
continued to show no differences between harvesting categories. Abundance o
f these gastropods, measured by catch per unit effort (CPUE), declined for
the two harvested species over the 5 yr following opening of the protected
shores. For Cellana, CPUE fell at sites in the reserve from 36% above explo
ited areas to similar values; for Turbo, CPUE values at the time of opening
were 200-300% higher in the protected areas, but then fell to match values
for exploited shores. These results show that legislative protection, whic
h applied to the entire coastline, is ineffective in this section of the Au
stralian coast, and effective protection requires physical barriers to excl
ude humans, or greatly increased enforcement.