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Viviparous rockfishes (Sebastes spp., family Scorpaenidae) mate and store sperm in the ovaries for several months prior to fertilization, as oocytes develop for the parturition season. Although multiple paternity has been documented in single-brooding rockfishes, paternity in consecutive broods of multiple-brooding species has not been studied. Analyses of multilocus microsatellite genotypes in both residual larvae left in the ovary from a previous parturition and upcoming fertilized broods in the same ovary demonstrated evidence of the same sires in consecutive broods in chilipepper (Sebastes goodei) and speckled (Sebastes ovalis) rockfishes. One S. goodei mother showed evidence of multiple paternity from the same two sires in both consecutive broods. The ability to retain sperm, even after a parturition event, for use in subsequent broods, confers an advantage to ensure fertilization and allows for extension of the parturition season. This life-history strategy provides a bet-hedging advantage in the California Current system, an environmentally dynamic ecosystem where larval survivorship and subsequent recruitment to adult populations can vary temporally by orders of magnitude.

Body colouration, a trait under strong selection, is influenced by the visual background of the environment. The stable influence of depth on visual background dynamics is due to light attenuation along the water column. Depth is also a key factor driving diversification in Sebastes rockfishes, influencing variations in several biological traits. Comparisons between closely related species suggest that brightly coloured species (red, orange, or yellow) tend to inhabit deeper waters and have slower growth rates compared to their shallow-water counterparts with dominance of dark colours (black, brown, or grey). Here, we used 377 photos from 100 Sebastes species, along with recently developed methods of colour quantification and phylogenetic comparative analyses, to assess this trend. Our analyses confirmed the separation of body colouration regarding depth, which was accompanied by differences in growth rates and morphological traits. This indicated that variations in body colourations are included in the ongoing correlational selection process dictated by depth. Analyses of closely related species indicated that depth is an initial driver of colour differentiation and that colour differences do not progressively increase with genetic divergences. We hypothesized that the bright-coloured rockfishes are found in deeper waters because in shallow environments they are more vulnerable to the potential negative effects of UV radiation and higher predation risk, while their predation successes are lessened, in comparison to dark-coloured rockfishes. Overall, this study emphasizes the intricate relationship between genetics, environment, adaptation, and the striking diversity of body colourations observed in Sebastes rockfishes. [ABSTRACT FROM AUTHOR]

Melanism is the presence of an excess of dark pigmentation in an animal, which causes a total or partial blackening of the skin. In fish, melanosis has been reported for a few species, indicating that it is not a common aspect and that it more frequently affects limnic species. The capture of a Sebastes oculatus female specimen, with complete melanism, is reported. The individual was captured by hand line, in the town of Isla Pájaro II, northern Chile. Its standard length is 31.5 cm and its total weight is 993 g. The general coloration of the body is dark gray. The fins do not have the orange hue characteristic of the species at their ends. The melanic condition in S. oculatus is very rare, it is the second time that it has been reported for this species, where the expression of a dark color would be beneficial for specimens that inhabit bottoms with little vegetation and between cracks. [ABSTRACT FROM AUTHOR]

Ecological diversification of Sebastes rockfishes has been mainly driven by depth and resource availability. Both ecological parameters exert selective pressures in colouration, communication systems, body, otolith shape, and prey–predation interactions. Accordingly, we hypothesized that ecomorphological divergences found in these components can reflect reduced interspecific competition among three rockfishes from the same species complex with sympatric occurrence in Seto Inland Sea (Japan). The narrower body shape and golden-brown colouration in Sebastes cheni suggest a more pelagic lifestyle than the other two species. Larger eye and otolith relative sizes, deeper body shape and red colouration suggest a deeper distribution for Sebastes inermis, in concordance with longer pectoral fins and dorsal spines to deal with increased foraging difficulty and predation risk because of its colouration. Meanwhile, smaller upper jaws, higher number of gill rakers, and black colouration of Sebastes ventricosus indicate a shallower distribution than S. inermis and preference for planktonic preys. Differences in colouration, eye size, and otolith descriptors support species-specific communication systems that are crucial to maintaining reproductive isolation. Therefore, the morphological divergences among these rockfishes reflect specific ecological divergences that allow their coexistence in sympatry and can ease their morphological identification. [ABSTRACT FROM AUTHOR]

Evidence is provided that biofouling of artificial substrata for estimating recruitment of nearshore reef fishes influences recruitment, and it is recommended that investigators consider the effects of fouling when estimating recruitment over space and time.

Fish communities at sub-tidal reefs and kelp beds at Santa Cruz Island in the Santa Barbara Channel change in response to shifts in oceanic conditions associated with the Pacific Decadal Oscillation (PDO), a long-lived El Niño-like pattern of variability in the northern Pacific Ocean. During the “warm” phase of the PDO, there is a greater abundance of “southern” fish species and a concomitant decrease in fishes normally associated with more northerly waters. The opposite occurs during “cool” periods.

The main goal of this project was to measure relative abundance, size and movement of nearshore fishes caught by anglers in a heavily fished area located north of San Francisco called Duxbury reef.This study is unique in the level of participation of about 200 anglers, all of whom volunteered to help catch, tag and release fish. The participation of these anglers was essential for data collection; and as importantly, it also gave scientists an opportunity to demonstrate fisheries science directly to this key "stakeholder" group.

As nearshore fish populations decline, many commercial fishers have shifted effort to deeper continental slope habitats to target fishes for which biological information is limited. One such fishery that developed in the northeastern Pacific Ocean in the early 1980s was for the blackgill rockfish, Sebastes melanostomus, a deepdwelling (300-800 m) species that congregates over rocky pinnacles, mainly from southern California to southern Oregon. Growth zone-derived age estimates from otolith thin sections were compared to ages obtained from the radioactive disequilibria of 210Pb, relative to its parent, 226Ra, in otolith cores of blackgill rockfish. Age estimates were validated up to 41 years, with a strong pattern of agreement supporting a longevity exceeding 90 years. Age and length data fitted to the von Bertalanffy growth function indicate blackgill rockfish are slow-growing (k = 0.040 females, 0.068 males) and that females grow slower than males, but reach a greater length. Age at 50% maturity, derived from previously published length-at-maturity estimates, was 17 years for males and 21 years for females. The results of this study agree with general life history traits already recognized for many Sebastes species, such as long life, slow growth, and late age at maturation. These traits may undermine the sustainability of blackgill rockfish populations when heavy fishing pressure, such as that which occurred in the 1980s, is applied.The canary rockfish (Sebastes pinniger) has been an important part of the recreational and commercial rockfish fisheries from southeast Alaska to southern California for a long time, but stocks have declined considerably over the past few decades. Based on age estimates from otoliths and other structures, longevity estimates vary from just over 20 years to more than 80 years. For the purpose of monitoring stocks, age composition is routinely estimated by counting growth zones in otoliths using the break-and-burn technique; however, age estimation procedures and high longevities for this species remain largely unvalidated. Typical age validation techniques have limited application for the canary rockfish because they are deep dwelling and appear be long-lived fish. In this study we have taken the unaged otolith of the pair from aged fish and have measured the disequilibria of lead-210 (210Pb) and radium-226 (226Ra) as an indicator of age estimate accuracy. The technique proved successful in determining a minimum longevity of about 51 years and provided strong support for the estimation procedures used to determine longevity at over 80 years.California Sea Grant funded publications that pre-date and resulted from this study are listed below. Please contact Allen H. Andrews allen.andrews@noaa.gov for further information.Andrews, A.H., K.H. Coale, J.L. Nowicki, C. Lundstrom, Z. Palacz, E.J. Burton and G.M. Cailliet. 1999. Application of an ion-exchange separation technique and thermal ionization mass spectrometry to 226Ra determination in otoliths for radiometric age determination of long-lived fishes. Can. J. Fish. Aquat. Sci. 56:1329–1338 (R/F-148)Andrews, A.H., G.M. Cailliet and K.H Coale. 1999. Age and growth of the Pacific grenadier (Coryphaenoides acrolepis) with age estimate validation using an improved radiometric ageing technique. Can. J. Fish. Aquat. Sci. 56:1339–1350 (R/F-148)Andrews, A.H., G.M. Cailliet, K.H. Coale, K.M. Munk, M.M. Mahoney and V.M. O’Connell. 2002. Radiometric age validation of the yelloweye rockfish (Sebastes ruberrimus) from southeastern Alaska. Mar. Freshwater Res. 53:139–146 (R/F-148)Kerr, L.A., A.H. Andrews, B.R. Frantz, K.H. Coale, T.A. Brown and G.M. Cailliet. 2004. Radiocarbon in otoliths of yelloweye rockfish (Sebastes ruberrimus): a reference time series for the coastal waters of southeast Alaska. Can. J. Fish. Aquat. Sci. 61:443-451.Stevens, M.M., A.H. Andrews, G.M. Cailliet, K.H. Coale, C.C. Lundstrom. 2004. Radiometric validation of age, growth, and longevity for the blackgill rockfish, Sebastes melanostomus. Fish. Bull. 102:711–722Andrews, A.H., E.J. Burton, L.A. Kerr, G.M. Cailliet, K.H. Coale, C.C. Lundstrom and T.A. Brown. 2005. Bomb radiocarbon and lead-radium disequilibria in otoliths of bocaccio rockfish (Sebastes paucispinis): a determination of age and longevity for a difficult-to-age fish. Proceedings of the 3rd International Symposium on Otolith Research and Application. Mar. Freshwater Res. 56:517–528Kerr, L.A., A.H. Andrews, B.R. Frantz, K.H. Coale, T.A. Brown, K. Munk and G.M. Cailliet. 2005. Age validation of quillback rockfish (Sebastes maliger) using bomb radiocarbon. Fish. Bull. 103(1):97–107Kerr, L.A., A.H. Andrews, G.M. Cailliet, T.A. Brown and K.H. Coale. 2006. Investigations of Δ14C, δ15N, and δ13C in vertebrae of white shark (Carcharodon carcharias) from the eastern Pacific Ocean. Environ. Biol. Fish. 77:337–353.Ardizzone, D.A., G.M. Cailliet, L.J. Natanson, A.H. Andrews, L.A. Kerr and T.A. Brown. 2006. Application of bomb radiocarbon chronologies to shortfin mako (Isurus oxyrinchus) age validation. Environ. Biol. Fish. 77:355–366.Andrews, A.H., L.A. Kerr, G.M. Cailliet, T.A. Brown, C.C. Lundstrom and R.D. Stanley. 2007. Age validation of canary rockfish (Sebastes pinniger) using two independent otolith techniques: lead-radium and bomb radiocarbon dating. Mar. Freshwater Res. 58:531–541

Local ecological knowledge (LEK) of resource users is a valuable source of information about environmental trends and conditions. However, many factors influence how people perceive their environment and it may be important to identify sources of variation in LEK when using it to understand ecological change. This study examined variation in LEK arising from differences in people's experience in the environment. From 2014 to 2016, we conducted 98 semi-structured interviews with subsistence fishers and recreational charter captains in four Alaskan coastal communities to document LEK of seven fish species. Fishers observed declines in fish abundance and body size, though the patterns varied among species, regions, and fishery sectors. Overall, subsistence harvesters provided a longer-term view of abundance changes compared with charter captains. Regression analyses indicated that the extent of people's fishing areas and their years of fishing experience were relatively important factors in explaining variation in fishers' perceptions of fish abundance. When taken together, perspectives from fishers in multiple regions and sectors can provide a more complete picture of changes in nearshore fish populations than any source alone. These findings underscore the importance of including people with different types of expertise in local knowledge studies designed to document environmental change. [ABSTRACT FROM AUTHOR]

Macrocystis pyrifera kelp beds play a significant ecological role along the coast of Chile. Besides their importance as food, protection structures, substrata, microhabitats and nurseries, regularly occurring natural disturbances (e.g. extremes of the climate variability El Niño–Southern Oscillation) and increased kelp exploitation affect these habitats. The present study aimed to test the dependence of reef fishes on Macrocystis pyrifera and to evaluate the effect of an enhanced habitat structure (experimental M. pyrifera bed) on the abundance, composition and spatial distribution on rock, on macroalgae, in the water column and on sand of the reef fish community. Boulders colonised by M. pyrifera were transported into three replicated experimental areas (9 m2 each) located in a barren ground area. Three barren ground areas (9 m2 each) without manipulation were selected as controls. The fish abundance, composition and spatial distribution on rock, on macroalgae, in the water column and on sand were recorded weekly by scuba diving over a period of 3 months, between 15 February 2007 and 13 June 2007 (4 months). Results indicate significantly higher abundances (mean = 225%) of fishes in the forested areas compared to the barren ground controls (mean = 3.71 fishes/9 m2 and 1.14 fishes/9 m2, respectively). Scartichthys gigas/viridis, Chromis crusma, Cheilodactylus variegatus and Isacia conceptionis numerically dominated the fish assemblages of the experimental kelp patches. Each fish species revealed different distributions in the forested areas: Scartichthys gigas/viridis was more abundant on rocks and C. variegatus in the macroalgae, whereas C. crusma and I. conceptionis preferred the water column above the experimental kelp bed. During the experimental time, the kelp lost some blades and some plants became detached. The overall number of fishes correlated with the declining kelp abundance (r = 0.964, p < 0.05). The fish species showed different responses to these changes in the experimental areas: C. variegatus and I. conceptionis declined in abundance, whereas the abundance of Scartichthys gigas/viridis remained constant. [ABSTRACT FROM AUTHOR]

Bottom-trawl surveys are widely used to generate data for developing habitat suitability models for rockfish species. However, bottom trawl selectivity varies with substrate type and can lead to biased and unreliable model outputs. Bottom-set gillnets provide more efficient and reliable data in untrawlable substrates, and fine-tuning bottom-trawl survey indices with supplementary gillnet survey data could enhance performance of rockfish habitat models. We applied this approach with bottom trawl and gillnet data for Sebasticus marmoratus in Ma’an Archipelago, China. Abundance indices and environmental data collected by the gillnet surveys were used to tune the bottom trawl survey data for empirical habitat suitability modeling of S. marmoratus . Under cross-validation, the habitat model based on tuned trawl data generated ecologically reliable suitability indices (SIs) and improved habitat suitability prediction for Sebasticus marmoratus compared to the habitat model developed using untuned trawl data. The data-tuning method developed in this study can be used to enhance the performance of habitat models of other demersal species whose habitats are not adequately sampled by bottom-trawl surveys. [ABSTRACT FROM AUTHOR]

Diversification of harvest portfolios can benefit resource users by providing increased flexibility to respond to regulatory, economic, and environmental pressures. These adaptations, while important for maintaining harvesting opportunities, can lead to conservation challenges by shifting effort to other species or habitats. Using semi-structured interviews with charter fishing captains (N = 52) and logbook data, we examined shifts in the diversity of target species portfolios in a major recreational fishery in Alaska over three decades. To understand the role of regulation in affecting what species charter captains choose to target, we contrasted harvest portfolios in communities from two regions with differing histories of regulation. Portfolio structure was dynamic, with the majority of respondents reporting changes in the number of harvested species, relative preference for different species, or both since the 1990s. Diversification emerged primarily as a result of increased retention of historically less-preferred species, such as rockfishes, sablefish, and Pacific cod. Patterns of rockfish retention in charter logbook data mirrored patterns in targeting reported by respondents. Southeast Alaska captains largely attributed portfolio diversification and shifts in species preferences to greater restrictions on harvest of a primary target species (Pacific halibut), while Southcentral Alaska captains identified shifting customer interests and declines in some target species as driving changes. Our findings suggest that avoiding unintended conservation impacts of single-species regulations requires broader recognition of the multispecies nature of recreational fishing in management. Understanding fisher behaviors, values, and motivations is essential, so that managers may better anticipate the responses of fishers to new regulations. [ABSTRACT FROM AUTHOR]

Fertilized eggs of Sebastes schlegelii, Sebastes pachycephalus and Sebastes hubbsi are morphologically similar under stereomicroscope. However, under the scanning electron microscope, significant differences in the ultrastructures of the egg surface among the three species were observed, and herein, a taxonomic key was proposed for future applications. A clustering analysis based on the ultrastructures of the egg surface and the diameter of the oil globule suggested that among the three species, S. hubbsi and S. pachycephalus were more genetically similar, while S. schlegelii had diverged earlier. The results agree with the conclusions drawn from morphological and molecular analyses on adult samples of the same species. [ABSTRACT FROM AUTHOR]

Abstract: Estimating a population's growth rate and year‐to‐year variance is a key component of population viability analysis (PVA). However, standard PVA methods require time series of counts obtained using consistent survey methods over many years. In addition, it can be difficult to separate observation and process variance, which is critical for PVA. Time‐series analysis performed with multivariate autoregressive state‐space (MARSS) models is a flexible statistical framework that allows one to address many of these limitations. MARSS models allow one to combine surveys with different gears and across different sites for estimation of PVA parameters, and to implement replication, which reduces the variance‐separation problem and maximizes informational input for mean trend estimation. Even data that are fragmented with unknown error levels can be accommodated. We present a practical case study that illustrates MARSS analysis steps: data choice, model set‐up, model selection, and parameter estimation. Our case study is an analysis of the long‐term trends of rockfish in Puget Sound, Washington, based on citizen science scuba surveys, a fishery‐independent trawl survey, and recreational fishery surveys affected by bag‐limit reductions. The best‐supported models indicated that the recreational and trawl surveys tracked different, temporally independent assemblages that declined at similar rates (an average of −3.8% to −3.9% per year). The scuba survey tracked a separate increasing and temporally independent assemblage (an average of 4.1% per year). Three rockfishes (bocaccio, canary, and yelloweye) are listed in Puget Sound under the US Endangered Species Act (ESA). These species are associated with deep water, which the recreational and trawl surveys sample better than the scuba survey. All three ESA‐listed rockfishes declined as a proportion of recreational catch between the 1970s and 2010s, suggesting that they experienced similar or more severe reductions in abundance than the 3.8–3.9% per year declines that were estimated for rockfish populations sampled by the recreational and trawl surveys. [ABSTRACT FROM AUTHOR]

The sensory drive hypothesis proposes that environmental factors affect both signalling dynamics and the evolution of signals and receivers. Sound detection and equilibrium in marine fishes are senses dependent on the sagittae otoliths, whose morphological variability appears intrinsically linked to the environment. The aim of this study was to understand if and which environmental factors could be conditioning the evolution of this sensory structure, therefore lending support to the sensory drive hypothesis. Thus, we analysed the otolith shape of 42 rockfish species ( Sebastes spp.) to test the potential associations with the phylogeny, biological (age), ecological (feeding habit and depth distribution) and biogeographical factors. The results showed strong differences in the otolith shapes of some species, noticeably influenced by ecological and biogeographical factors. Moreover, otolith shape was clearly conditioned by phylogeny, but with a strong environmental effect, cautioning about the use of this structure for the systematics of rockfishes or other marine fishes. However, our most relevant finding is that the data supported the sensory drive hypothesis as a force promoting the radiation of the genus Sebastes. This hypothesis holds that adaptive divergence in communication has significant influence relative to other life history traits. It has already been established in Sebastes for visual characters and organs; our results showed that it applies to otolith transformations as well (despite the clear influence of feeding and depth), expanding the scope of the hypothesis to other sensory structures. [ABSTRACT FROM AUTHOR]

The article discusses a study that used mitochondrial DNA (mtDNA) D-loop partial sequences to investigate the genetic differentiation and species boundaries between Pacific and Atlantic lineages of the Patagonian rockfish Sebastes oculatus. Sequences were acquired for 47 individuals from various locations off the Pacific and Atlantic coasts of South America for S. oculatus and one off the coast of South Africa for S. capensis. Topological distinctiveness between the South American and South African sebastes populations supported the existence of two phylogenetic species. Extensive larval disposal is cited as one reason for gene flow between S. oculatus populations in the Atlantic and Pacific.

Between 1995 and 2006, manned submersible fish surveys were conducted on the sea floor throughout the Southern California Bight. A total of 401 dives (comprising 1,015 transects and 14,373 habitat patches) were made in waters between 19 and 365 m deep. All natural habitat types were included, although both soft sea floors and rocky reefs were surveyed more than any other type. A total of 717,526 fishes, representing a minimum of 137 species and 47 families, were observed. Rockfishes (genus Sebastes), with a minimum of 50 species and 647,495 individuals (90.2% of all fishes observed), dominated most of the habitats. The most abundant species, squarespot ( Sebastes hopkinsi), halfbanded ( Sebastes semicinctus), shortbelly ( Sebastes jordani), and pygmy rockfishes ( Sebastes wilsoni), are dwarf taxa that either school or aggregate. The most abundant non-rockfish species was the benthic and territorial blackeye goby ( Rhinogobiops nicholsii). Both species richness and overall fish densities were highest in the shallowest sites. Most of the fishes in all habitats were small (≤20 cm TL long) and economically important species were generally uncommon. Forty-four species were found to be characteristic of the study area (occurring in at least 5% of the transects) and these species formed three faunal associations centered around depths of 62, 105, and 168 m. Based on size frequency distributions, at least 18 of the characteristic species exhibited ontogenetic movements, with young-of-the-year and older juveniles living in relatively shallow waters and larger individuals generally in deeper depths. In this study, the abundance of juvenile widow rockfish ( Sebastes entomelas), and the virtual absence of adults, in southern California waters may demonstrate an ontogenetic northward movement of this species. This research implies that substantial harvesting of larger species by commercial and recreational fishers has helped alter some fish assemblages, allowing small and “weedy” species to thrive. [ABSTRACT FROM AUTHOR]

We characterized habitat requirements of juvenile cowcod, Sebastes levis, using information from surveys conducted aboard the manned research submersible Delta. We conducted 303 dive surveys on rocky banks and outcrops in water depths between 28 and 365 m in southern and central California, covering 483 km (963,940 m2) of seafloor. We counted 549,263 fishes from at least 134 species; 216 individuals were juvenile cowcod, S. levis, of 45 cm or less in total length (TL). Juvenile cowcod occupied depths between 52 and 330 m and demonstrated ontogenetic shifts in their habitat associations. Small fish (5–20 cm TL) lived primarily among cobbles or cobbles and small boulders. As fish grew, they moved into high-relief rock habitats, including boulder fields and rock ridges. Small cowcods were found with pygmy, Sebastes wilsoni, and swordspine, Sebastes ensifer, rockfishes. Larger juveniles often associated with juvenile bocaccio, Sebastes paucispinis, juvenile widow rockfish, Sebastes entomelas, and squarespot rockfish, Sebastes hopkinsi. Our study resulted in a characterization of seafloor habitats on a small spatial scale that is relevant to juvenile cowcod nursery areas, which is important when considering effective management strategies for this overfished species. [ABSTRACT FROM AUTHOR]

The nearshore (less than 20 m depth) demersal fish community in Prince William Sound, Alaska, is dominated by Pacific cod, Gadus macrocephalus, pricklebacks (mostly Arctic shanny Stichaeus punctatus), gunnels (mostly crescent gunnels Pholis laeta), a variety of greenlings (Hexagrammidae) and sculpins (Cottidae). During summer, the spatial distribution of fishes, over scales of 100's of m to 10's of km, varied by habitats characterized by different vegetation types. Juvenile Pacific cod and greenlings were numerically dominant in eelgrass, Zostera marina, beds. Pricklebacks and sculpins were dominant in areas with an understory of the kelps Agarum cribrosum and Laminaria saccharina. Greenlings and sculpins were the most abundant demersal fishes in more exposed sites with a canopy of Nereocystis luetkeana and an understory of L. bongardiana. Measured habitat variables, including vegetation type, slope, vegetation biomass, and substratum type, explained a significant proportion of the variation in the presence or absence of most fishes. The relative importance of different habitat characteristics varied between taxonomic groups of fishes. Vegetation type explained a significant proportion of variation for cod, rockfishes, and ronquils. Juvenile cod were closely associated with eelgrass, while rockfish and ronquils were associated with kelps. Pricklebacks and rockfishes were more frequently observed on steeply sloped shorelines, while ronquils were more often found at sites with higher biomass of vegetation. Within A. cribrosum habitats, more greenlings and sculpins were present at sites where algal biomass was higher. Also, sculpins were more abundant in deeper water and gunnels were more abundant in shallow water within this habitat. These associations may not have been causative. However, evidence suggests that some differences between fish communities in eelgrass and Agarum beds may have been causally related to vegetation characteristics. The possible roles of different vegetation types as refugia from predators or as sources of prey are discussed. [ABSTRACT FROM AUTHOR]

Offshore rocky banks are ecologically important refuge habitats for a number of U.S. commercial groundfish species. However, they are challenging to survey, and data on the abundance and ecology of fish populations at deep banks are limited. We used the remotely operated vehicle ROPOS to carry out visual surveys at two sites on Cherry Bank in the Southern California Bight, eastern Pacific Ocean. We observed differences in fish assemblages related to depth and habitat type and found that rockfishes (Sebastes spp) made up 65% of fishes recorded. Rockfishes and combfish (Zaniolepis spp) were associated with relatively shallow areas with hard substrate whereas flatfishes (Pleuronectiformes) and poachers (Agonidae) were found on unconsolidated sediments. Thornyheads (Sebastolobus spp) and hagfishes (Myxinidae) mainly occurred in areas of patchy habitat. Habitat and depth explained 52% of the variation in fish assemblages between transects with habitat explaining a greater proportion of the variation than depth. We observed large differences in the number of juvenile rockfishes and Sebastomus rockfishes between study sites with hard substrates and also had higher abundances of juvenile rockfishes versus sites characterized by mixed substrates. With the exception of unidentified Sebastomus , the current design had relatively low power to reliably detect observed differences for most taxa, so we report the number of additional transects that would be required to detect a 50% increase in densities. These data provide a baseline on groundfish densities and habitat associations at Cherry Bank and key information for the design of future work including Bayesian approaches to estimating coast-wide abundance. • ROPOS ROV was used to survey fish assemblages at Cherry Bank. • Rockfishes (Sebastes spp) made up 65% of fishes recorded. • Habitat and depth explained 52% of the variation in fish assemblages. • Habitat was more important than depth in determining fish assemblages. • Juvenile rockfishes were much more common on hard substrates than on mixed ones. [ABSTRACT FROM AUTHOR]