Effects of fishing on fish assemblages at the reefscape scale

Abstract

We studied the persistence of fishing impacts on coral reef fish assemblages by sampling 2 protected and 2 fished locations, using random replicate stereo baited remote underwater video. At each location we sampled a variety of coral reef habitats on 4 separate occasions between 2006 and 2007. We tested for consistency in differences in the biomass of target and nontarget species, trophic groups and overall assemblages. Generally, target species were more abundant and/or larger at protected locations. Many non-target species were either more abundant or depleted at protected sites, and some of these species were significantly larger or smaller. Trophic groups such as piscivores, piscivore invertivores, invertivores and planktivores were consistently more abundant within protected locations. Generally, greater numbers of species and individuals were found on protected reefs, though this was not consistent in all cases across all 4 sampling periods. These findings are consistent with the theory that protected areas can increase the abundance of not just target species but overall fish assemblages. These findings provide evidence for ecological mechanisms such as predator-prey interactions, competitive release, and benefits to invertivores, omnivores and other non-target groups from the presence of more abundant and larger target species within marine protected areas.

Linking Protection with the Distribution of Grouper and Habitat Quality in Seychelles

“…Similar but nonsignificant trends were found for a further two species, and for A. leucogrammicus the abundance was higher in protected areas, regardless of size category. While our results were consistent with many other studies [8,[16][17][18][19] that MPAs typically hold higher densities of fish (indicated by higher average counts), our mean counts of fish indicate that for those species with a significant interaction term this is likely due to higher counts of small and medium sized fish rather than an increase in the presence of larger fish.…”

“…Many have found that marine reserves lead to an increase in the density/biomass of fish [8,[16][17][18], and there are some studies that have found that MPAs typically hold a greater number of larger individuals [9,[17][18][19], indicating that protection allows these fish to mature to greater ages than they would if they were exposed to fishing. However, studies such as Mateos-Molina et al [10] have also found a higher abundance of small-sized species and early life stages suggesting greater recruitment.…”

“…Research has shown that overfishing, especially of specific trophic and feeding groups, can upset ecosystem stability [11,18,[23][24][25][26]; therefore, MPAs can help maintain the balance in marine communities, preventing cascading effects to the wider environment. Protection can even have positive feedbacks, allowing ecosystems to recover in deteriorated areas by allowing the recovery of trophic complexity [11,18,27,28].…”

Identifying priority habitat for conservation and management of Australian humpback dolphins within a marine protected area

“…), so these inshore reefs may serve as important foraging areas for this population. Fish assemblages at SZ in NMP have higher biomass and abundance than at sites where fishing is permitted 62 . It was hypothesised by 36 that consistent prey availability may be influencing regular use of NMP by humpback dolphins.…”

Demographic characteristics of Australian humpback dolphins reveal important habitat toward the southwestern limit of their range

“…A total of 6 sanctuary zones (no fishing zones) are within the boundaries of the MPA in the study area (see DPaW & DoF 2014). Fitzpatrick et al (2015) found that, within NMP, fish assemblages at sanctuary zones had higher biomass and abundance than at sites where fishing is permitted. Given that protected areas in general can increase overall abundance and biomass of fish assemblages, and that humpback dolphins are thought to be opportunistic feeders (Parra & Jedensjö 2014), consistent prey availability may be influencing regular use of NMP by humpback dolphins, compared to the adjacent (unprotected) Exmouth Gulf.…”