Assessing the effectiveness of marine reserves and evaluating species recovery after closure to towed mobile fishing gear; Associate Editor, Steph Januchowski-Hartley comments on the article, Recovery linked to life history of sessile epifauna following exclusion of towed mobile fishing gear by Kaiser et. al.
Reserves, or protected areas, are frequently used to mitigate impacts from human uses. In marine waters these reserves are often established to afford protection to ecosystems and species that are otherwise impacted by fishing practices. However, there remains a lack of evidence on the effectiveness of reserves, for example, for mitigating impacts from fishing pressure. At the same time the duration for which a reserve has been in place can also influence the perceived or measured effectiveness of an area for achieving a particular goal or objective. This is especially true when evaluating the effectiveness of reserves for longer-lived species, because of the timescales required for sampling and monitoring species’ characteristics and persistence.
In their new article, Kaiser et al. aim to better-understand the link between species’ life histories and reserve effectiveness. The effectiveness of reserves for mitigating impacts to different species could be dependent on species life history characteristics. Kaiser et al. explore this further, by evaluating changes in species abundance and size across a 10-year period in the Lyme Bay Special Area of Conservation (SAC), UK, after closure to towed mobile fishing gear. They used video surveys to record abundance and size of six different benthic species at different sites within the Lyme Bay SAC with varied duration of protection (0, 1, 8, and 10 years).
Kaiser et al. provide an important empirical advance in quantifying the types of fishing activities that can be permitted within the marine reserve to allow adequate recovery times for species.
A key finding was that recovery is evident for long-lived benthic dwelling species within the Lyme Bay SAC. However, while abundance of longer lived species like Ross Coral and Pink Seafans increased with time under protection they have not fully recovered in the 10 years of protection. The study also found that, contrary to expectations based on previous studies (Beukers-Stwear et al, Sciberras et al.) that the abundance of King Scallops only increased modestly with time. The authors highlight that these observed differences could be a reflection of temporal and spatial variation in recruitment, factors that can ultimately influence measured and perceived reserve effectiveness. Although not explicitly accounted for in this study, human influences such as pollution and environmental change could explain some of the unexpected observation in the study, particularly to do with changes in organism size, which could relate to changes in water temperature over the study period.
It is essential that we evaluate and understand the effectiveness of different conservation interventions, such as marine reserves, and changes in the fishing gears used, to determine if continued investment is justified or not. Kaiser et al. demonstrate the benefit of repeated – temporal – sampling to enhance our understanding of species recovery periods with marine reserves, and from different fishing pressures. Ultimately, Kaiser et al. provide an important empirical advance in quantifying the types of fishing activities that can be permitted within the marine reserve to allow adequate recovery times for species.
Read the full article, Recovery linked to life history of sessile epifauna following exclusion of towed mobile fishing gear in Journal of Applied Ecology.