Legislative vs. practical protection of an intertidal shoreline in southeastern Australia

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.