Variation in Responses of Fishes across Multiple Reserves within a Network of Marine Protected Areas in Temperate Waters

Abstract

Meta-analyses of field studies have shown that biomass, density, species richness, and size of organisms protected by no-take marine reserves generally increase over time. The magnitude and timing of changes in these response variables, however, vary greatly and depend upon the taxonomic groups protected, size and type of reserve, oceanographic regime, and time since the reserve was implemented. We conducted collaborative, fishery-independent surveys of fishes for seven years in and near newly created marine protected areas (MPAs) in central California, USA. Results showed that initially most MPAs contained more and larger fishes than associated reference sites, likely due to differences in habitat quality. The differences between MPAs and reference sites did not greatly change over the seven years of our study, indicating that reserve benefits will be slow to accumulate in California’s temperate eastern boundary current. Fishes in an older reserve that has been closed to fishing since 1973, however, were significantly more abundant and larger than those in associated reference sites. This indicates that reserve benefits are likely to accrue in the California Current ecosystem, but that 20 years or more may be needed to detect significant changes in response variables that are due to MPA implementation. Because of the high spatial and temporal variability of fish recruitment patterns, long-term monitoring is needed to identify positive responses of fishes to protection in the diverse set of habitats in a dynamic eastern boundary current. Qualitative estimates of response variables, such as would be obtained from an expert opinion process, are unlikely to provide an accurate description of MPA performance. Similarly, using one species or one MPA as an indicator is unlikely to provide sufficient resolution to accurately describe the performance of multiple MPAs.

Mercury offloaded in Northern elephant seal hair affects coastal seawater surrounding rookery

“…To put that amount in perspective, the San Francisco Bay covers ∼1,100 km 2 , drains 40% of the state of California (26,27), and receives an estimated annual load of 8.0 kg MeHg from external sources such as rivers and point source discharges (25). Conversely, the Año Nuevo State Marine Conservation Area covers only 26.4 km 2 (28), indicating that the magnitude of annual inputs from pinniped colonization constitutes a relevant, previously unaccounted for, source of MeHg to that marine reserve.…”

Assessing population recovery inside British Columbia’s Rockfish Conservation Areas with a remotely operated vehicle

“…The much longer generation time for these species as well as the sporadic recruitment success of rockfish, implies that it will take longer than 3-7 years for reserve effects to develop as a result of increased growth and reproductive output of these species in RCAs. Similarly, Starr et al (2015) found strong reserve effects in an MPA that had been closed since 1973 but not in newer reserves in California that were sampled within the first 7 years of protection. They projected that MPAs in Central California may take 20 years or more to show significant changes in response variables (Starr et al, 2015).…”

“…Similarly, Starr et al (2015) found strong reserve effects in an MPA that had been closed since 1973 but not in newer reserves in California that were sampled within the first 7 years of protection. They projected that MPAs in Central California may take 20 years or more to show significant changes in response variables (Starr et al, 2015). Most rockfishes distributed along the continental slope did not show a greater proportion of large fish in closed areas of a large RCA in the US, unlike other species with shorter lifespans (Keller et al, 2014).…”

“…In order to improve the assessment of marine reserves, Claudet and Guidetti (2010) recommend that the actual fishing pressure outside of an MPA be quantified, rather than assumed, when effectiveness is assessed relative to external controls. Other management measures coincident with the creation of conservation areas complicates the evaluation of RCAs (Keller et al, 2014;Starr et al, 2015). In addition to establishing RCAs, DFO also greatly reduced the directed catch (Total Allowable Catch, TAC) for inshore rockfishes.…”

Tailoring Ecological Monitoring to Individual Marine Reserves: Comparing Longline to Hook‐and‐Line Gear to Monitor Fish Species

“…For example, hook-and-line gear is used to sample rocky reefs that are home to many commercially and recreationally important species, as trawl gear would snag in these complex, hard-bottom habitats. Fishery-independent hook-and-line surveys (hereafter "hook and line" refers to pole-and-line gear specifically) have expanded in recent years in the nearshore waters of the northeastern Pacific Ocean both to assess reef fish abundance (Wendt and Starr 2009;Harms et al 2010) and to monitor marine reserve performance (Haggarty and King 2006;Yochum et al 2011;Huntington et al 2014;Starr et al 2015). The numbers of marine reserves are growing in both California, where 124 marine managed areas were implemented between 2007 and 2013 (Kirlin et al 2013), and Oregon, where 13 marine managed areas were implemented between 2012 and 2016.…”