Sessile and mobile components of a benthic ecosystem display mixed trends within a temperate marine reserve

Abstract

Despite recent efforts to increase the global coverage of marine protected areas (MPAs), studies investigating the effectiveness of marine protected areas within temperate waters remain scarce. Furthermore, out of the few studies published on MPAs in temperate waters, the majority focus on specific ecological or fishery components rather than investigating the ecosystem as a whole. This study therefore investigated the dynamics of both benthic communities and fish populations within a recently established, fully protected marine reserve in Lamlash Bay, Isle of Arran, United Kingdom, over a four year period. A combination of photo and diver surveys revealed live maerl (Phymatolithon calcareum), macroalgae, sponges, hydroids, feather stars and eyelash worms (Myxicola infundibulum) to be significantly more abundant within the marine reserve than on surrounding fishing grounds. Likewise, the overall composition of epifaunal communities in and outside the reserve was significantly different. Both results are consistent with the hypothesis that protecting areas from fishing can encourage seafloor habitats to recover. In addition, the greater abundance of complex habitats within the reserve appeared to providing nursery habitat for juvenile cod (Gadus morhua) and scallops (Pecten maximus and Aequipecten opercularis). In contrast, there was little difference in the abundance of mobile benthic fauna, such as crabs and starfish, between the reserve and outside. Similarly, the use of baited underwater video cameras revealed no difference in the abundance and size of fish between the reserve and outside. Limited recovery of these ecosystem components may be due to the relatively small size (2.67 km(2)) and young age of the reserve (<5 years), both of which might have limited the extent of any benefits afforded to mobile fauna and fish communities. Overall, this study provides evidence that fully protected marine reserves can encourage seafloor habitats to recover, which in turn, can create a number of benefits that flow back to other species, including those of commercial importance.

Trade-offs in marine protection: multispecies interactions within a community-led temperate marine reserve

“…Therefore, as we could not employ a before-after BACI approach (Hilborn et al, 2004;Sale et al, 2005), we monitored crustacean populations within the reserve and in several control areas over a period of four years. This was done on the assumption that a divergence in population characteristics over time would be indicative of an effect (see Howarth et al, 2015aHowarth et al, , 2015b.…”

Marine Conservation Begins at Home: How a Local Community and Protection of a Small Bay Sent Waves of Change Around the UK and Beyond

“…Given the uniqueness of the Lamlash Bay NTZ as the only highly protected marine reserve in Scotland, and the availability of scientifically documented evidence of ecological recovery within the NTZ boundaries (Figures 4, 5, Howarth et al, 2011Howarth et al, , 2015aHowarth et al, ,b, 2016, the NTZ played a key role in making the case for designating the South Arran MPA and other MPAs throughout Scotland (COAST, 2012). More significantly, COAST's campaigns and collaborations with scientists have been vital for ensuring the new MPAs receive adequate protection, ensuring a lasting and far-reaching legacy.…”

“…Annual photo-quadrat surveys between 2011 and 2013 revealed a variety of seabed habitats, such as sponges and macroalgae, had become more abundant within Lamlash Bay NTZ than adjacent areas (Howarth et al, 2015a). Diver transects found that the recovery of these habitats had increased the abundance of juvenile scallops by two to five times compared to neighboring fishing grounds (Howarth et al, 2015b).…”

“…Also detailed is evidence of how protection has benefited seabed habitats and species of commercial interest. For full details, seeHowarth et al (2011Howarth et al ( , 2015a,Stewart and Howarth (2016),Crimmins (2018), and James (2019).…”

Effects of Pollution on Marine Organisms

“…The authors found that sediment and biota samples collected in the Bay demonstrated that EUNIS classification is useful at some levels for specific habitats; however, the biotic composition of other areas were found to be sufficiently different from those described in EUNIS that a total of 13 potentially new classes were identified by the authors. Benthic habitats and biotopes off the coast of Norway were modeled using video transectHowarth et al 2015a). While data collected from diver surveys, video surveys, and photographic analysisindicated that several epifaunal assemblages were significantly more abundant within the reserve, no statistical difference in fish abundance was detected within the reserve compared to outside of the reserve.…”