Recovery linked to life history of sessile epifauna following exclusion of towed mobile fishing gear

Abstract

The use of reserves as conservation tools is widespread. However, evaluating the effectiveness of reserve implementation for long‐lived species has been problematic as it requires sampling programmes over long timescales that are appropriate to species' longevity and recovery rates. In the sea, towed bottom fishing gears alter the biodiversity and ecosystem services provided by benthic communities and habitats. Marine reserves have been used to manage these impacts but our understanding of the drivers of their effectiveness for the conservation of temperate reefs is incomplete. We examined the effectiveness of marine reserves for recovery of temperate reef fauna in relation to their life history. We used an underwater video to sample six species with different life histories across 60 sites that varied in the duration of protection from towed mobile fishing gear at 0, 1, 8 and 10 years. Species with a high dispersal potential and less habitat specific requirements such as soft corals and king scallops recovered to close to their carrying capacity in <3 years. In contrast, the longer‐lived Ross coral and pink seafans increased in abundance but had not fully recovered; with their projected recovery time being 17–20 years. Ongoing recovery was evident for long‐lived species as their mean body size increased significantly across all treatments, whereas shorter‐lived species such as queen scallops did not change in size and were assumed to have fully recovered. Synthesis and applications. This study shows that the recovery rates of biota depend on life‐history factors, such as larval longevity and dispersal potential. Recovery for species that had low dispersal potential and specific habitat requirements was slow and could take >20 years. This suggests activities such as bottom trawling or dredging should be avoided where such species occur if their conservation is an objective. In contrast, species with high dispersal potential and less habitat specific requirements had shorter recovery timescales of c. 2‐3 years and would be more amenable to managed trawl frequencies in areas where activities such as fishing occur.

Choosing best practices for managing impacts of trawl fishing on seabed habitats and biota

“…Bottom trawling is commonly prohibited over habitat types that are both easily disturbed and slow to recover, such as seagrasses, sponges, corals and other endemic or rare types of seabed communities (Clark et al, ; Freese, ; Kaiser et al, ; Neckles, Short, Barker, & Kopp, ). The size of areas designated for protection can be small or large depending on the specific management objectives and enforcement capabilities.…”

“…Rieser et al, ), thus serving as useful ecological references for trawled areas. Maximum conservation benefits are expected for sessile/habitat‐forming species and when aggregations of slow‐growing species with moderate dispersal rates are protected from trawling (Fulton et al, ; Kaiser et al, ). However, MPAs that are not located in areas of high benthos abundance or diversity may have little impact on the state of benthic ecosystems and can displace trawling to more sensitive areas (Hiddink et al, ; Sciberras et al, ).…”

“…Bottom trawling is commonly prohibited over habitat types that are both easily disturbed and slow to recover, such as seagrasses, sponges, corals and other endemic or rare types of seabed communities (Clark et al, 2016;Freese, 2001;Kaiser et al, 2018;Neckles, Short, Barker, & Kopp, 2005 Permanent prohibitions by habitat type provide effective protection when locations of sensitive habitats can be identified and prohibitions can be introduced prior to significant physical disturbance (Howell, Davies, & Narayanaswamy, 2010). The designated areas are usually small, so the benefits to overall ecosystem function and food production are limited, but they may confer economic benefits to local economies that rely on artisanal fisheries or eco-tourism (Gell & Roberts, 2002).…”

Do static and dynamic marine protected areas that restrict pelagic fishing achieve ecological objectives?

“…, Kaiser et al. , Kenchington et al. ): local abundance and biomass; mean length; recruitment and absolute biomass; and species richness and diversity.…”

Editorial: One size does not fit all: Do taxonomic biases in marine connectivity studies reduce effectiveness of marine conservation?

“…Our interpretation of the connectivity of marine systems has implications for a range of marine conservation management challenges, from design principles for marine protected area (MPA) networks (Gaines, Gaylord, & Largier, ), to determining how much seafloor disturbance (e.g. mining, trawl fishing, dredging) should be allowed to minimize impacts to benthic communities (Kaiser, Hormbrey, Booth, Hinz, & Hiddink, ; Miller, Thompson, Johnston, & Santillo, ). Understanding connectivity is also important for predicting the spread of invasive species (Inglis, Hurren, Oldman, & Haskew, ) and for restoration management in selecting locations based on source–sink dynamics and the likelihood of ongoing recruitment (Lundquist, Oldman, & Lewis, ).…”