In his talk entitled “Fish, Fisheries and the Conservation of Biological Diversity” Peter J Auster divided the discussed material into the categories of a discussion of basic fish ecology, fisheries practices, and the effects of fisheries management practices on diversity.  The underlying focus seemed to be on the effects of fishing practices where the benthic habitats were disturbed.

Discussion of Fish
The basic needs of fish are simply defined as the needs to reduce predation risk and to acquire prey.  Obviously, the species are adapted to accomplish these tasks in relation to their habitats.  Most studies have typically focused on complex nearshore habitats, such as coral reefs or kelp forests.  However, even in well studied areas there is difficulty in describing where fish live and what the necessary factors are.  For example, what are the limits or optimal temperature, depth boundary conditions, sediments, and structures for habitation?  It is only through recent use of submersibles and ROVs that areas inaccessible to SCUBA have begun to be characterized.  The focus of this lecture was on the habitat of the northeast and the associated benthic habitat.  The seafloor habitats of the outer shelf may include gravel with scattered boulders, sandy gravel ridges, or deep water coral systems.  The benthic invertebrates including corals, anemones, and hydroids provide structure and habitat.  There is often a high degree of associated fauna, many of which have never been characterized.

Discussion of Fisheries
Auster began this section by quoting Pauly’s (in)famous article stating that “fishing is the most widespread human disturbance in the sea”.   One of these effects is the problem of bycatch, whereby nearly half of organisms caught in fishing operations are undesired and discarded.  The majority of this bycatch is through the practice of bottom trawling.  There is also the direct effect on the seafloor, which varies based on habitat type and structure.  In Georges Bank, the trawled areas were generally reduced to bare gravel, while undisturbed areas contained nearly full benthic cover by hydroids, bryozoans, and other invertebrates.  In the case of deepwater corals, which could be over 8000 years old, dredging can quickly destroy these systems.  The effects of these habitat disturbances can result in shifts in detrital pathways, decreased primary production, and a shift to small opportunistic species.

Discussion of Fisheries Management and Biodiversity
As previously mentioned, the disturbance to the benthos can both directly and indirectly decrease the biodiversity of invertebrate and fish species.  Underlying causes of this are based in fisheries management practices.  Currently, sector based management is very fish focused and collateral damage to invertebrates and the benthos may not be a priority.  Furthermore, it is widely believed that these areas are heavily overfished.  Auster argues that a reduction in fishing pressure, despite continued use of benthic disturbing methods, could greatly reduce habitat destruction and therefore loss of biodiversity.  There needs to be a progression beyond single species models, as well as a greater understanding of thresholds and trajectories of communities and their potential shift to other states.  Finally, integrated management including ecosystem services must be utilized in order to prevent destructive practices and arrest the rate of loss of associated fauna.