Rocky Reef Fish Research Articles

A coherent, representative, and bioregional marine reserve network shows consistent change in rocky reef fish assemblages

AbstractWorldwide, several countries have established coherent, representative, and large‐scale networks of marine reserves to conserve biodiversity. Very few have, however, published systematic assessments of the ecological responses to this network protection, hindering broad understanding of their generality, utility, and efficacy. We present data collected from systematic sampling of rocky reef fish assemblages at sites across a network of 27 no‐take marine reserve areas (NTMR) and 27 partially protected areas (PPA) nested within multiple marine parks (regional networks) across three Australian bioregions spanning >1000 km of coastline (7° latitude) to test the generality of ecological change across this network. We also sampled 18 reference areas (outside of the marine parks) to provide an independent assessment of potential NTMR effects and also to assess whole marine park effects. Baited remote underwater video (BRUV) was used to sample fishes between depths of 20–40 m over austral winters in four years (2010, 2011, 2015, and 2016). Despite substantial bioregional differences in fish assemblages, large and consistent effects of NTMR protection were detected across all bioregions for a key commercially and recreationally harvested species, Chrysophrys auratus (pink snapper). There were substantial increases in relative abundance of C. auratus in NTMR compared with fished zones through time (effect sizes >150%). The wider assemblage of targeted fish (excluding C. auratus) only showed relatively small effects of protection (~11%) with trends observed for site‐attached wrasses (labrids) and planktivores (e.g., commercially fished Scorpis lineolata) that are recreationally and commercially harvested. Furthermore, the relative abundance of non‐target or by‐catch species generally did not differ among management zones across the bioregional network. These results highlight how NTMR can be used to assess the ecological effects of fishing and wider environmental management, and can be incorporated into ecosystem‐based management for reef species more generally. Importantly, the provision of robust evidence of the performance and generality of NTMR over large‐spatial scales (e.g., bioregions) provides greater confidence in the expected outcomes from marine reserve networks as a conservation management approach.

Unexpected effects of coastal storms on trophic ecology of two rocky reef fish species

Coastal storm risks have been increasing over the last couple of decades, affecting both marine infrastructure and human security. Nevertheless, the ecological impact on intertidal marine fishes has not been addressed yet. We carried out a field experiment during austral summer 2018, using statistical wave parameters, characterizing coastal storms as a factor, and the gut content of two sympatric intertidal triplefins, Helcogrammoides chilensis and Helcogrammoides cunninghami, as a proxy for trophic interactions. Three locations were sampled before and after the arrival of three consecutive summer coastal storm events. From all gut contents, a total of 16,597 prey items were found. Both species are micro-carnivorous, predating mostly on harpacticoid copepods, amphipods and chironomid larvae, without significant differences in prey composition with the passing of the summer coastal storms. However, after coastal storms, heavier-at-length fish (0.05–0.5 g weight gain) were found in the intertidal. Indeed, after the impact of the coastal storms, H. chilensis increased their ingestion of larger prey (amphipods, chironomid larvae), while H. cunninghami decreased the number of prey ingested. When compared between species, the feeding success after the passing of coastal storms was greater for H. chilensis than H. cunninghami. Finally, trophic overlap between species was high, but after the coastal storms passed, it decreased noticeably due to small changes in proportion of large chironomid and gammarid amphipods in the diet. Therefore, summer coastal storms affected the foraging behavior, increasing the weight of two recurrent cryptobenthic rocky reef fish from central Chile. In a broader ecological context, the shift from pelagic (i.e., copepods) to benthic prey (i.e., amphipods, polychaetes) may change the relative contribution and the subsidy production in nearshore habitats via pelagic-benthic coupling.

Spatiotemporal variations in density and biomass of rocky reef fish in a biogeographic climatic transition zone: trends over 9 years, inside and outside the only nearshore no-take marine-protected area on the southern Brazilian coast.

Biogeographical transition zones are important areas to investigate evolutionary ecological questions, but long-term population monitoring is needed to better understand ecological processes that govern population variations in such edge environments. The southernmost Brazilian rocky reefs are the southern limit of distribution for 96% of the tropical ichthyofauna of the western Atlantic. The Arvoredo Marine Biological Reserve is the only nearshore no-take marine-protected area (MPA) located in this transition zone. The main aim was to investigate how the populations of rocky reef fish species vary in density and biomass in space and over time, inside and outside the Arvoredo MPA. This study presents results based on a 9 year (2008-2017) underwater visual census monitoring study to evaluate the density and biomass of key fish species. Variations in density and biomass were detected for most species. Factors and mechanisms that may have influenced spatial variation are habitat structural complexity and protection from fisheries. Temporal variations, otherwise, may have been influenced by species proximity to their distributional limit, in synergy with density-dependent mechanisms and stochastic winter temperature oscillations. The MPAs harbour higher density and biomass for most species. Nonetheless, a prominent temporal decline in the recruitment of Epinephelus marginatus calls into question the continuous effectiveness of the MPA.

Costs and benefits of towed videos and remotely operated vehicles for sampling shallow reef habitats and fish

Where several different tools are available for research, the costs and benefits associated with each option become an important part of the selection process. Towed video (ToV) and remotely operated vehicles (ROVs) are both widely used to assess shallow reef benthic habitats and fish assemblages, but quantitative data on their comparative performance is limited. The relative abilities of commercially available ToV and ROV were assessed using two low-cost (less than A$10000), manually deployable systems. These systems were deployed to collect photographs of marine habitats and videos of fish assemblages along six 200-m transects at three separate sites. The time required to operate each system and the specific limitations and advantages of each system were compared. Both systems performed equally in terms of the resolution of data collected on benthic habitats and fish assemblages on shallow reefs. However, ToV required significantly less time (~60% less) to collect data than ROV, and should allow cost savings with no loss in data quality. We recommend ToV as a cost-effective and easily deployable system for assessing rocky reef habitats and fish assemblages.

Review of fish trap fisheries from tropical and subtropical reefs: Main features, threats and management solutions

Fish traps are extensively used in tropical and subtropical reef fisheries. Despite this, there is a significant lack of extensive and consecutive research concerning the basic aspects of trap fishing. We herein compile the available information from the main coral and rocky reef fish trap fisheries, and compared their main aspects (i.e., mesh size, CPUE, catch composition, ghost fishing, and management) to assess the dynamics of these fisheries and their environmental impact. The analysis revealed that most fish stocks showed declining trends, with only few species under heavy management being capable of withstanding high fishing pressure. In other fisheries, due to fishing down the web, miscellaneous reef fish comprised the bulk of the catch, while the proportion of high-value landed species was insignificant. Gear restrictions remain the most common management method in trap fisheries; however, even the minimum mesh size has not been ubiquitously enforced, while due to great variability of targeted fish species, use of a uniform mesh size is highly unlikely. Other management tools, such as, restrictions in effort, size, and species, temporal and spatial closures were also widely used, but effective only when well enforced and interconnected. Rates of trap loss widely differed as well as the reported rates of ghost fishing mortality. In most cases, incorporation of escape panels resulted in almost complete elimination of ghost fishing. However, further research is required concerning these issues.

Small-Scale Coastal Fishing Shapes the Structure of Shallow Rocky Reef Fish in the Aegean Sea

Shallow rocky reef fish assemblages were studied in sites of low versus high fishing pressure (FP) across different parts of the Aegean Sea, in order to assess community structure at a large scale and investigate spatial variability in relation to FP, depth, and geographic location. A total of 15 pairs of high and low FP sites were selected (18 sites in North Aegean, 12 in South Aegean). The level of FP was defined based on a fishing pressure index specifically developed for coastal small-scale fisheries in the region. In each site, fish communities were investigated at two depth zones (5 and 15 m). Number of species, fish size (TL) and abundance were recorded along strip transects through underwater visual surveys. Abundance and TL were used to estimate biomass, and fish species were assigned to distinct trophic and commercial status groups. An 8-fold range in fish density and a 14-fold range in fish biomass were detected, while community structure was affected by all spatial variables considered (FP, depth, geographic location). The N Aegean sites scored higher in number of species and biomass of carnivorous fish, whereas the S Aegean had a higher biomass of several allochthonous and thermophilous species. Abundance and biomass estimates were higher in low FP sites, and primarily at the 15 m depth zone, where low FP sites had 2 times higher abundance and 2.8 times higher biomass. However, differences were mainly due to an increase of fish with low or no commercial value, whereas biomass of highly-priced fish was overall low. Given that sites of lower FP represent areas of lower conflicting interests for fisheries whilst providing enhanced biomass levels, they should be included in future marine conservation planning schemes, as they could contribute to the replenishment of fisheries and the boosting of conservation benefits provided by MPAs, once properly managed.

Assessing drivers of rocky reef fish biomass density from the Southern California Bight

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 628:125-140 (2019) - DOI: https://doi.org/10.3354/meps13103 Assessing drivers of rocky reef fish biomass density from the Southern California Bight Daniel J. Pondella II1,*, Susan E. Piacenza1,2, Jeremy T. Claisse1,3, Chelsea M. Williams1,3, Jonathan P. Williams1, Amanda J. Zellmer1, Jennifer E. Caselle4 1Vantuna Research Group, Occidental College, Los Angeles, CA 90041, USA 2Department of Biology, University of West Florida, Pensacola, FL 32514, USA 3Department of Biological Sciences, California State Polytechnic University, Pomona, CA 91768, USA 4Marine Science Institute, University of California, Santa Barbara, CA 93106, USA *Corresponding author: pondella@oxy.edu ABSTRACT: Biomass is often used as a metric for valuing and comparing ecosystems. However, many variables contribute to the amount of biomass an ecosystem can maintain; thus, it is necessary to evaluate the driving forces of patterns in biomass variation across sites. Here we utilized datasets associated with nearshore rocky reef fish biomass that span the Southern California Bight, using generalized least-squares modelling within the information-theoretic approach. Fish density, length, invertebrate density, algal density, and reef characteristics (relief and substrate type) were visually sampled at 89 sites, via SCUBA, with a random stratified sampling design using belt transects across depth strata in <20 m depth. Fish data were converted to biomass using published length-weight relationships. In addition to our visual surveys, spatially resolved explanatory variables included sea surface temperature, sea surface chlorophyll a, maximum wave height, kelp biomass, fishery harvest intensity index, a new remote sensing method for calculating reef slope, and distance to the 200 m isobath, a novel characteristic. All models in the confidence model set (ΔAICc <2) for total fish biomass included the variables sea surface temperature, distance to the 200 m isobath, sea surface chl a, slope, and the standard deviation of substrate and relief. Not all rocky reefs in the SCB equally support high densities of fish biomass, and our results suggest that an optimal combination of physical characteristics and forcing drive this variation. The novel variable, distance to the 200 m isobath, may be applicable for understanding fish biomass variation in marine ecosystems. KEY WORDS: Spatial habitat patterns · Reef fish biomass density · Generalized least-squares modeling · Remote sensing · Southern California Bight Full text in pdf format Supplementary material PreviousNextCite this article as: Pondella DJ II, Piacenza SE, Claisse JT, Williams CM, Williams JP, Zellmer AJ, Caselle JE (2019) Assessing drivers of rocky reef fish biomass density from the Southern California Bight. Mar Ecol Prog Ser 628:125-140. https://doi.org/10.3354/meps13103 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 628. Online publication date: October 10, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Effects of habitat complexity and temporal variation in rocky reef fish communities in the Santos estuary (SP), Brazil

Abstract Rampant human activities within estuaries and adjacent areas lead to a significant loss of habitat for many fish species and decreases the quality of the remaining habitats. In this context, we investigated the effects of habitat complexity and temporal variation on the composition and diversity of rocky reef fishes in two coastal islands in southeastern Brazil, namely Ilha do Mato e Ilha das Palmas. We filmed seven independent transects of 400 m2 in each island in each of the four seasons during a year using remotely operated vehicle (ROV). Using the video records and accessories attached to the ROV, we collected information on environmental variables, habitat complexity, species richness, abundance and diversity. Our pooled data showed 13,993 individuals belonging to 56 species, 13 orders and 24 families of marine fish. Nineteen species (34%) occurred in all four seasons. Nine species (16%) were exclusive to spring, seven (12.5%) were exclusive to autumn, three (5.4%) occurred in summer, and only two species (3.5%) were exclusive to winter. Fish assemblages varied according to the habitat complexity. The environmental variables varied between islands and climatic seasons. Numerical abundance and species richness were positively associated with habitat complexity. The interaction between maximum depth and habitat complexity resulted in a greater abundance of individuals. In addition, species richness was negatively correlated to both salinity and maximum depth. However, increasing both variables simultaneously caused an increase in expected richness, due to interaction effects. Trophic diversity was positively correlated with temperature, whilst habitat diversity did not vary with any of the studied independent variables. Furthermore, we found significant differences between Ilha do Mato and Ilha das Palmas in abundance and in richness, which may be due to streams that present re-circulations bordering the latter and that carry organic matter from the Santos estuary. Finally, our non-destructive and non-sacrificial methodology allowed the successful assessment of fish assemblages in different environments and at different times and the description of important patterns, which may be useful for public policies and management.

Influence of habitat condition on shallow rocky reef fish community structure around islands and headlands of a temperate marine protected area

The University of Newcastle and NSW Department of Primary Industries provided funding with research conducted under NSW DPI Animal Care and Ethics Committee permit 10/09

Temperate zone coastal seascapes: seascape patterning and adjacent seagrass habitat shape the distribution of rocky reef fish assemblages

Whilst the composition and arrangement of habitats within landscape mosaics are known to be important determinants of biodiversity patterns, the influence of seascape patterning and connectivity on temperate reef fish assemblages remains largely unknown. We examined how habitat patterns at multiple spatial scales (100–1000 m) explained the abundance and diversity of temperate reef fish in a reef-seagrass dominated seascape. Fish assemblages were surveyed using remote underwater videos deployed on 22 reefs in Jervis Bay, NSW, Australia. Using full-subset GAMMs, we investigated if habitat area, edge, structural connectivity and a metric for habitat diversity (Shannon’s diversity index) of reef and seagrass can predict variations in a temperate reef fish assemblage. A key finding of the study was that temperate reefs close ( 6.25 ha) seagrass meadows contained greater abundance and diversity of fish. A consistent negative correlation was also found between reef area (> 0.01 ha) and the fish assemblage. The influence of seascape metrics on the abundance of fishes varied with functional traits (trophic groups, mobility and habitat associations). Fish-seascape relationships occurred at a range of spatial scales with no single scale being solely important for structuring the fish assemblage. We demonstrate that it is important not to view reef habitats in isolation, rather consider a reefs context to adjacent seagrass when predicting the distribution of temperate reef fish. This finding improves current understanding of the multi-scale factors structuring temperate reef fish assemblages and highlights the importance of reef-seagrass connectivty for the management of temperate marine ecosystems.

Refuge choice specificity increases with predation risk in a rocky reef fish

Reef ecosystems are structurally complex and characterized by an array of abiotic (e.g., rocks and crevices) and biotic (sessile benthic organisms) physical features, many of which having the potential to act as refuge for prey organisms. Small cryptic reef fish species, including the redlip blenny, Ophioblennius trinitatis, rely on refuges to survive against predators, suggesting that adequate refuge choice is an important part of this species' antipredator strategy. Here we investigated blennies' selectivity in refuge choice along its ontogeny simulating predation risk in the field and laboratory. Our results revealed that when exposures to a predator model in the field, blennies chiefly fled to only two refuge types, namely crevices and sea urchins, and these choices reflected blennies' ontogeny. Furthermore, blennies' densities and flight-initiation distances were positively and negatively correlated with sea urchin densities, respectively, underscoring the refuge role played by this benthic organism. On high risk conditions, the fish translated into faster retreat to shelter and to higher refuge selectivity, when compared to low risk. The choices observed in situ were partly similar among initial and terminal phases. These findings suggest that small reef fishes may be selective in their refuge choice even using habitats with high structural complexity. This choice selectivity may be part of an antipredator strategy that considers the relative level of protection offered by the physical features of habitats, along with their conspicuity within rocky reef ecosystems.

Deciphering the Origin and Evolution of the X1X2Y System in Two Closely-Related Oplegnathus Species (Oplegnathidae and Centrarchiformes).

Oplegnathus fasciatus and O. punctatus (Teleostei: Centrarchiformes: Oplegnathidae), are commercially important rocky reef fishes, endemic to East Asia. Both species present an X1X2Y sex chromosome system. Here, we investigated the evolutionary forces behind the origin and differentiation of these sex chromosomes, with the aim to elucidate whether they had a single or convergent origin. To achieve this, conventional and molecular cytogenetic protocols, involving the mapping of repetitive DNA markers, comparative genomic hybridization (CGH), and whole chromosome painting (WCP) were applied. Both species presented similar 2n, karyotype structure and hybridization patterns of repetitive DNA classes. 5S rDNA loci, besides being placed on the autosomal pair 22, resided in the terminal region of the long arms of both X1 chromosomes in females, and on the X1 and Y chromosomes in males. Furthermore, WCP experiments with a probe derived from the Y chromosome of O. fasciatus (OFAS-Y) entirely painted the X1 and X2 chromosomes in females and the X1, X2, and Y chromosomes in males of both species. CGH failed to reveal any sign of sequence differentiation on the Y chromosome in both species, thereby suggesting the shared early stage of neo-Y chromosome differentiation. Altogether, the present findings confirmed the origin of the X1X2Y sex chromosomes via Y-autosome centric fusion and strongly suggested their common origin.

Nearshore environmental conditions influence larval growth and shape changes for a temperate rocky reef fish

Coastal upwelling and other oceanographic processes, exert influences on phenotypic traits of early life stages of marine fishes. However, it remains to elucidate the environmental effects on the morphology of fish larvae. Using geometric morphometrics and otolith microstructure of a temperate rocky reef fish, the labrisomid blenny Auchenionchus crinitus (Labrisomidae), we studied the larval growth, mortality and morphospace of four consecutive cohorts, hatched between austral winter and summer off central Chile. We hypothesize that coastal environmental conditions will influence early life traits of this cryptobenthic fish. The winter cohort, which inhabited colder and well-mixed nearshore waters, grew more slowly and had a more hydrodynamic head shape, while the summer cohort, which lived in warmer and stratified waters, grew faster, but had a more robust shape. Cohorts expressed less ontogenetic allometry as seasons progressed, suggesting that the seasonal increment in water temperature reduces the shape changes with size during larval development. Also, slower- and faster-growing larvae showed large variation from the consensus shape, e.g. had the largest shape disparity. Nonetheless, all cohorts showed similar mortality rates during the first month of life. Finally, increases in zonal wind stress (i.e. sea breeze) and decreases in the sea temperatures (i.e. upwelling events) increased the growth rates of older (> 15 days old) larvae. Therefore, for this cryptobenthic species, differences in growth rate and body shape are related to the seasonal increase in water temperature, and local-scale meteorological conditions.

Organic matter derived from kelp supports a large proportion of biomass in temperate rocky reef fish communities: Implications for ecosystem‐based management

Abstract The relative availability of alternative organic matter sources directly influences trophic interactions within ecological communities. As differences in trophic ecology can alter the productivity of communities, understanding spatial variability in trophic structure, and the drivers of variability, is vital for implementing effective ecosystem‐based management. Bulk stable isotope analysis (δ13C and δ15N) and mass balance calculations were used to examine patterns in the contribution of organic matter derived from macroalgae to food webs supporting temperate reef fish communities in two contrasting coastal waterways on the South Island of New Zealand: Fiordland and the Marlborough Sounds. Ten fish species common to both regions were compared, with up to 40% less organic matter from macroalgae supporting omnivorous species in the Marlborough Sounds. The largest differences in trophic position were found in those species exploited by fisheries. Furthermore, stratified surveys of abundance and species biomass combined with trophic position data were used to calculate regional differences in the contribution of macroalgae to whole fish communities in terms of density of biomass. In Fiordland, over 77% of the biomass of exploited reef fishes was supported by macroalgae, compared with 31% in the Marlborough Sounds. Surveys of macroalgal density and species composition in the two regions indicated that regional differences in trophodynamics may be explained by a lack of macroalgal inputs to the food web in the Marlborough Sounds. The findings demonstrate large regional differences in the incorporation of benthic and pelagic sources of organic matter to food webs supporting reef fish communities, highlighting the need for ecosystem‐based approaches to management to recognize spatial variability in primary production supporting coastal food webs.

Genome sequence of the barred knifejaw Oplegnathus fasciatus (Temminck & Schlegel, 1844): the first chromosome-level draft genome in the family Oplegnathidae.

BackgroundThe barred knifejaw (Oplegnathus fasciatus), a member of the Oplegnathidae family of the Centrarchiformes, is a commercially important rocky reef fish native to East Asia. Oplegnathus fasciatus has become an important fishery resource for offshore cage aquaculture and fish stocking of marine ranching in China, Japan, and Korea. Recently, sexual dimorphism in growth with neo-sex chromosome and widespread biotic diseases in O. fasciatus have been increasing concern in the industry. However, adequate genome resources for gaining insight into sex-determining mechanisms and establishing genetically resistant breeding systems for O. fasciatus are lacking. Here, we analyzed the entire genome of a female O. fasciatus fish using long-read sequencing and Hi-C data to generate chromosome-length scaffolds and a highly contiguous genome assembly.FindingsWe assembled the O. fasciatus genome with a total of 245.0 Gb of raw reads that were generated using both Pacific Bioscience (PacBio) Sequel and Illumina HiSeq 2000 platforms. The final draft genome assembly was approximately 778.7 Mb, which reached a high level of continuity with a contig N50 of 2.1 Mb. The genome size was consistent with the estimated genome size (777.5 Mb) based on k-mer analysis. We combined Hi-C data with a draft genome assembly to generate chromosome-length scaffolds. Twenty-four scaffolds corresponding to the 24 chromosomes were assembled to a final size of 768.8 Mb with a contig N50 of 2.1 Mb and a scaffold N50 of 33.5 Mb using 1,372 contigs. The identified repeat sequences accounted for 33.9% of the entire genome, and 24 003 protein-coding genes with an average of 10.1 exons per gene were annotated using de novo methods, with RNA sequencing data and homologies to other teleosts. According to phylogenetic analysis using protein-coding genes, O. fasciatus is closely related to Larimichthys crocea, with O. fasciatus diverging from their common ancestor approximately 70.5–88.5 million years ago.ConclusionsWe generated a high-quality draft genome for O. fasciatus using long-read PacBio sequencing technology, which represents the first chromosome-level reference genome for Oplegnathidae species. Assembly of this genome assists research into fish sex-determining mechanisms and can serve as a resource for accelerating genome-assisted improvements in resistant breeding systems.

Rocky reef fish community composition remains stable throughout seasons and El Niño/La Niña events in the southern Gulf of California

The main effects of El Niño and La Niña on fish are increases in mortality rates, abundance and recruitment variation, and expansion/restriction in the range of distribution and spawning areas. Potentially, the interactions with seasonal effects can further exacerbate or dampen fluctuations in these parameters. The objective of this work, therefore, was to characterize the possible differences in the reef fish community structure in two seasons of the year (warm/cold) and between years (2010/2012) following El Niño-La Niña events. There were no significant differences in mean species richness between years. Furthermore, although more than twice the number of individuals was observed in the year after La Niña (2012) compared to the year following El Niño (2010), there were no significant differences with respect to mean abundance per transect. The total number of species recorded was slightly higher in the cold season, with 68 species across both years. In contrast, the total abundance was higher in the warm season. However, differences between seasons were neither significant for mean species richness nor for mean abundance. Neither season nor year exhibited a significant effect on community composition. The cold season in the Gulf of California is characterized by intense winds which generate a greater mixed layer; this, in turn, increases productivity, with cascading effects on higher trophic levels. In contrast, the presence of nitrogen-fixing picocyanobacteria which increase the levels of primary production may be a factor leading to maintaining a similar fish abundance in the warm season. Fluctuations between seasons and years of study were observed for some individual species, which may be related to oceanic productivity and reproductive periods. The results obtained in this work indicate that seasonality and climatic phenomena such El Niño and La Niña do not have a marked effect on community attributes of rocky reef fish in the southern Gulf of California, which apparently form a seasonally stable community, despite some fluctuations in individual species.

Network of small no-take marine reserves reveals greater abundance and body size of fisheries target species.

No-take marine reserves (NTRs), i.e. areas with total fishing restrictions, have been established worldwide aiming to promote biodiversity and ecosystem conservation. Brazil has 3.3% of its exclusive economic zone protected by 73 different NTRs, however, most of them currently lack scientific knowledge and understanding of their ecological role, particularly regarding rocky reefs in subtropical regions. In this context, this study aimed to contrast a network of NTRs with comparable fished sites across a coastal biogeographic gradient to investigate the effect of fishing and habitat variability on the abundance and body size of rocky reef fish. We used Baited Remote Underwater stereo-Video (stereo-BRUVs) and Diver Operated stereo-Video (stereo-DOVs) systems to simultaneously sample reef fish and habitat. Model selection and results identified habitat and biogeographic variables, such as distance from shore, as important predictor variables, explaining several aspects of the fish assemblage. The effect of protection was important in determining the abundance and body size of targeted species, in particular for epinephelids and carangids. Conversely, species richness was correlated with habitat complexity but not with protection status. This is the first study using these survey methods in the Southwestern Atlantic, demonstrating how a network of NTRs can provide benchmarks for biodiversity conservation and fisheries management.

Latitudinal variation in structure and function of conspicuous reef fish assemblages along the western Gulf of California

The Gulf of California is characterized by great biodiversity, high biological productivity and important fisheries. Studies on community structure of the reef fish fauna in the region have been conducted mainly in central and southern areas and, except for a few studies that have focused on cryptic species, there are no comparisons of the fish assemblages along this 1,600 km sea. In this study, we examine how diversity and community structure of rocky reef fishes vary with the latitude in the north, central and southern part of the west side of the Gulf of California. We conducted stationary visual censuses in observation cylinders (5 m radius) in 6 locations between Bahia de los Angeles (29° N) and Los Cabos (22° N) and estimated the following ecological descriptors and indexes: species richness, abundance, Shannon diversity, Pielou evenness, average taxonomic distinctness, and average trophic level. In addition, we used ordination analysis to determine the degree of similarity among study areas. Our results identified 3 distinct zones: north (29° N), central (27° N to 24° N) and south (24° N to 22° N).

Rocky reef fish assemblage structure in coastal islands of southern Brazil

Within the Brazilian province, rocky reefs and submerged outcrops are among the most important habitats for reef fishes, providing suitable habitats for the development of reef fish communities and consequently sheltering a high ecological diversity. Rocky reef fish assemblages were sampled in seven coastal islands in South Brazil by strip transects of 40 m 2 by the underwater visual census to obtain density (fish 40 m -2 ) and biomass (g 40 m -2 ). Fish species were also categorized according to trophic category and geographical distribution. In total, 526 strip transects were performed, covering an area of 21,040 m 2 , providing 19,377 fish, distributed among 73 species of 34 families. Itacolomis Island presented the highest density, followed by Veado Island. Regarding biomass, Itacolomis Island and Pedra da Baleia were the most representative rocky reefs. Mobile invertebrate predator was the trophic category with the highest density and biomass. A total of 60% of the species occur in the Western Atlantic, 20% are Transatlantic and 9.6% are endemic to the Brazilian Province. Our results indicate that despite the similarity in the taxonomic composition among islands, the observed differences in densities and biomass, highlight singular assemblage structures, whether by environmental and/or anthropogenic factors, and dominated by few species, both in density and biomass.

Parasitic copepods affect morphospace and diet of larvae of a temperate reef fish.

The effects of ectoparasites on larvae of the clingfish Gobiesox marmoratus were evaluated at the dietary and morphometric levels. The larvae and ectoparasites were collected by nearshore plankton samplings during October, November and December 2013 off El Quisco Bay, central Chile. The standardized abundance of total larvae and those ectoparasitized larvae (PL) was positively related and high parasite prevalence was found throughout the sampling period (up to 38%). Geometric morphometrics analyses indicate main changes in the shape through early ontogeny and subtle but significant variations between PL and non-parasitized larvae (NPL). Prey composition varied between PL and NPL; small size (<6 mm standard length, LS ) parasitized larval G. marmoratus ate mostly gastropod larvae, whereas small non-parasitized specimens ate mainly cirripede nauplii. All larger (>8 mm LS ), pre-settlement stages parasitized by Trifur and, or Caligus copepods had content in their gut, suggesting that ectoparasites did not diminish prey capture in host with larger size. Morphometric and dietary changes occurring during larval development were decoupled, both for PL and NPL. The maintenance of a slender, more hydrodynamic body through pelagic development and the ingestion of less-mobile prey in PL suggests non-lethal effects of ectoparasitism on rocky-reef fish larvae.