bioRxiv preprint doi: https://doi.org/10.1101/422147; this version posted September 19, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 1 Network of small no-take marine reserves reveal greater abundance and 2 body size of fisheries target species 3 4 5 Fernanda A. Rolim1,2*, Tim Langlois3, Pedro F. C. Rodrigues2, Todd Bond3, Fábio S. Motta4, 6 Leonardo M. Neves5, Otto B. F. Gadig2 7 8 9 1 Universidade Estadual Paulista (UNESP), Instituto de Biociências, Câmpus de Rio Claro. Rio 10 Claro, São Paulo, Brazil. 11 2 Universidade Estadual Paulista (UNESP), Laboratório de Pesquisa em Elasmobrânquios, 12 Instituto de Biociências, Câmpus do Litoral Paulista, São Vicente, São Paulo, Brazil. 13 3 The UWA Oceans Institute and School of Biological Sciences, The University of Western 14 Australia, Perth, Western Australia, Australia. 15 4 Universidade Federal de São Paulo (UNIFESP), Laboratório de Ecologia e Conservação 16 Marinha, Instituto do Mar, Santos, São Paulo, Brazil. 17 5 Departamento de Ciências do Meio Ambiente, Universidade Federal Rural do Rio de Janeiro 18 (UFRRJ), Campus Três Rios, Rio de Janeiro, Brazil. 19 20 21 * Corresponding author 22 E-mail: [email protected] bioRxiv preprint doi: https://doi.org/10.1101/422147; this version posted September 19, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 23 Abstract 24 No-take marine reserves (NTRs), i.e. areas with total fishing restrictions, have been 25 established worldwide aiming to provide biodiversity and ecosystem conservation. Brazil has 26 established NTRs, but currently lacks scientific knowledge and understanding of their 27 ecological role, particularly regarding rocky reefs in subtropical regions. Consequently, this 28 study aimed to contrast NTR, from the 30 year old Tupinambás Ecological Station, and 29 comparable fished sites across a coastal biogeographic gradient to investigate the effect of 30 fishing and habitat variability on the abundance and body-size of rocky reef fish. We used 31 Baited Remote Underwater stereo-Video (stereo-BRUVs) and Diver Operated stereo-Video 32 (stereo-DOVs) systems to simultaneously sample reef fish and habitat. Model selection and 33 results identified habitat and biogeographic variables, such as distance from shore, as important 34 predictor variables, explaining several aspects of the fish assemblage. The effect of protection 35 was important in determining the abundance and body-size of targeted species, in particular for 36 epinephelids and carangids. Conversely, species richness was correlated with habitat 37 complexity and not with protection status. This is the first study to publish data using these 38 novel survey methods in the Southeastern Atlantic and demonstrate their utility, in combination 39 with an established network of NTR's, to provide benchmarks for conservation and fisheries 40 management. 41 42 43 Key-words: Marine reserves, fisheries effects, functional groups, TransectMeasure, 44 EventMeasure, GAM. bioRxiv preprint doi: https://doi.org/10.1101/422147; this version posted September 19, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 45 Introduction 46 47 No-take marine reserves (NTRs) have been established worldwide as a management 48 strategy mostly aiming to recover marine biodiversity from effects of fisheries. It is well 49 documented that these areas can provide refuge to marine life, increasing local abundance, 50 species richness, body size and the reproductive capacity of fish [1–4]. 51 Networks of NTRs can be used to investigate effects of fishing across biogeographic 52 gradients, with the aim of estimating benchmarks for conservation and fisheries management. 53 Besides facing direct fisheries effects from biomass removal, NTRs have also highlighted 54 indirect effects, where the removal of large carnivores in areas without protection can result in 55 a higher abundance of prey species, leading to a trophic reorganization [5–7]. 56 It is also well documented that fish assemblage structure will vary with physical, 57 chemical and biological factors across biogeographic and habitat gradients through space [8– 58 10]. In particular, distance from the coast and topographic complexity have shown to increase 59 species richness, abundance and biomass of reef fish [11–16]. It is therefore important for any 60 investigation of the effects of fishing to be able to control for these covariates across any inside 61 versus outside NTR comparison. 62 Brazil has 8500 km of coastline and a territorial sea that, together with the Exclusive 63 Economic Zone, encompasses 4 million km2. Of this area, 26.4% is protected by 177 marine 64 protected areas (MPAs), of which 73 are NTR representing 3.3% of the country's marine waters 65 [17]. However, the few studies available about the effects of Brazilian NTRs on fish 66 assemblage are concentrated in the northern part [18], southern part [19,20] or offshore islands 67 [21,22], with a lack a studies in the transition zones and small coastal NTR networks. 68 Coastal habitat on the northern coast of Brazil (north of 19°S) are dominated by coral 69 reefs, whereas in southern regions (between 19-28°S) they are typified by rocky reefs. In bioRxiv preprint doi: https://doi.org/10.1101/422147; this version posted September 19, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 70 general, the Brazilian province concentrates high number of endemic species and biomass of 71 organisms [23–26]. In the transition zone between tropical and subtropical-temperate 72 environments (20˚S to 23˚S), the mixture of habitat types results in some of the highest species 73 diversity of benthic [27] and reef fish species recorded in Brazil [23]. These transitional reefs 74 are biologically rich and complex environments where it is vitally important to use the 75 established network of NTR's, in the region, to increase our ecological understanding and 76 provide benchmarks for conservation and fisheries management. 77 Historically, NTRs in Southwestern Atlantic have been assessed using underwater 78 visual census (UVC) (e.g. [18,19,21,22]). However, biases involving interobserver variability, 79 underrepresentation of species targeted by fisheries, as well as inaccuracy of species 80 identification and size estimates are likely to occur [28,29]. In order to overcome this issue, the 81 use of videos to collect data has been increasingly adopted [30,31], especially since rapid 82 advancements in video technology and accessibility to cheaper and higher quality equipment. 83 Importantly, methods using such technologies create a permanent record allowing fish 84 identification to be confirmed by experts and revisited when necessary. 85 Baited Remote Underwater stereo-Video (stereo-BRUV) and Diver Operated stereo- 86 Video (stereo-DOV) are being widely employed to assess diverse aspects of fish assemblages 87 [32–35]. Stereo-video techniques provide accurate body-size and range measurements of 88 individuals from the three-dimensional calibration of imagery (Harvey and Shortis, 1996). 89 Stereo-BRUV have been found to sample a wide range of species without precluding estimates 90 of herbivorous species [36] and can be applied across a wide variety of habitats and depths 91 [34]. Also, as a remote sensing technique, it detects large and mobile animals which usually 92 avoid divers and active fishing gears [32,33], but has a range of acknowledge biases and 93 limitations (see Langlois et al. [37]). Conversely, the presence of a diver may impact the bioRxiv preprint doi: https://doi.org/10.1101/422147; this version posted September 19, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 94 abundance of fish recorded using stereo-DOVs [33,38], suggesting that a combination of 95 methods more effectively samples the fish assemblage [33,39]. 96 In expanding our knowledge of ichthyofauna in the Southeastern Atlantic, it is 97 important that non-destructive sampling methods are adopted that enable robust estimates of 98 fisheries species inside and outside NTRs. This study is the first assessing fish assemblages 99 using stereo-BRUVs and stereo-DOVs in Southwestern Atlantic and Brazil, and aims to to 100 generate robust data for conservation and fisheries management in the region. We aim to 101 investigate the response of the fish assemblage to environmental and habitat variables, as well 102 as the effect of fishing using comparison with NTRs. We hypothesize that: (1) abundance and 103 body-size of targeted fish groups will be greater inside NTRs; whereas (3) non-target fish 104 abundance and species richness will be explained better by habitat and biogeographic variables. 105 106 Material and methods 107 108 Study site 109 The Ecological Station (ESEC) of Tupinambás is a no-take reserve located on the 110 northern coast of São Paulo State, Brazil, Southeastern Atlantic. The ESEC was established in 111 1987 [40] and is divided into two sectors; sector I is in the archipelago of Alcatrazes located 112 approximately 43 km from of São Sebastião, São Paulo.