Sand Goby Research Articles

Hydro-morphological features and functional structure of fish assemblages mediate species isotopic niches in estuaries

Despite the popularity of stable isotope analysis (Carbon and Nitrogen), the drivers of species isotopic niches and their consequences on food web functioning remained poorly described, especially in estuaries. Here, we hypothesised that species niche characteristics are influenced by ecosystem hydro-morphological features and the functional structure of fish assemblages. The trophic niches of four fish species (Dicentrarchus labrax, Pomatoschistus minutus, Sprattus and Platichthys flesus) and overlap between them were compared during two consecutive autumns in eight estuarine ecosystems of the northeast Atlantic Ocean. Our findings demonstrated a relative steadiness of trophic positions of fish in estuaries, despite a high level of interspecific variability. The seabass generally occupied the higher trophic position, followed by the sand goby, while the flounder and sprat were at the lowest position in the food web. Species isotopic niches and overlap were mediated by some estuarine features, including estuary size and intertidal extent, but also by biotic interactions at the intra- and inter-specific levels, as reflected by the influence of fish abundance and functional diversity metrics. Our results support the statement that the intertidal area is a pivotal factor in regulating trophic interactions, by promoting niche partitioning and diversification of trophic resources between species. Moreover, niche size and dietary divergence of species decreased with increasing regularity of trophic strategies within assemblages, suggesting that species occupied more restricted trophic niches when they were less subjected to competition for the same food resources. These findings emphasize the importance of local conditions and the functional composition of assemblages in modulating the trophic resources consumed by fish in estuarine environments.

Fractionation of the Caspian sand goby epidermal exudates using membrane ultrafiltration and reversed-phase chromatography: an investigation on bioactivities.

Bioactive peptide-based drugs have gained exceeding attention as promising treatments for infectious and oxidative-stress-related diseases, are exacerbated by the advent and spread of various multidrug-resistant bacteria and industrial lifestyles. Fish skin mucus has been recognized as a potential source of bioactive peptides, providing the first line of fish defense against invading pathogens which are targeted here to be explored as a new source of biopharmaceutics. Peptide fractions were isolated from the epidermal exudates of Caspian sand goby, Neogobius fluviatilis pallasi, by solid-phase extraction (SPE), ultrafiltration, and reversed-phase chromatography. The resulting fractions were characterized for their antibacterial and antioxidant properties, and results showed that the molecular weight fraction < 5kDa represented the highest (p < 0.05) bacterial inhibition activity against Staphylococcus aureus and Bacillus subtilis as well as scavenging activity against DPPH and ABTS radicals. Overall, these results introduce the epidermal mucus of Caspian sand goby as a valuable source of bioactive compounds that can be considered new and efficient biopharmaceutics.

Reproductive biologies of Psammogobius knysnaensis and Caffrogobius gilchristi in a warm-temperate South African estuary

Reproductive biologies (spawning period, length at maturity and fecundity) of the Knysna sand goby Psammogobius knysnaensis and the Prison goby Caffrogobius gilchristi were investigated between September 2018 and August 2019 in the warm-temperate Sundays Estuary, South Africa. The two species reproduced during the same period (spring and summer) with peak reproduction occurring in January. P. knysnaensis egg production was higher than C. gilchristi and was not affected by fish size. Although C. gilchristi egg production increased with fish size, this was not significant. P. knysnaensis reached LM50 at smaller sizes than C. gilchristi. Reproductive periods were likely coupled with prey availability, as phytoplankton and zooplankton abundances are highest in warm-temperate estuaries during this period. The ability of these gobies to reproduce at small sizes (< 40 mm TL), which is an adaptive trait of many r-selected species, underpins their high abundance in South African estuaries as they are well adapted to stochastic environments.

First Record of the Asian Sand Goby, Favonigobius gymnauchen (Bleeker, 1860) (Teleostei, Gobiidae) from Arabian Coast of India and Species Confirmation Through DNA Barcoding of COI Gene

First Record of the Asian Sand Goby, Favonigobius gymnauchen (Bleeker, 1860) (Teleostei, Gobiidae) from Arabian Coast of India and Species Confirmation Through DNA Barcoding of COI Gene

Endemic fish calling: Acoustics and reproductive behaviour of the Neretva dwarf goby Orsinigobius croaticus.

The Neretva dwarf goby Orsinigobius croaticus (Gobiiformes, Gobionellidae) is an endemic fish native to the freshwaters of the Adriatic Basin in Croatia and Bosnia and Herzegovina, a Mediterranean Biodiversity Hotspot. Due to its limited distribution range, specific karst habitat and endangered status, laboratory studies on reproductive biology are scarce but crucial. Herein, we investigated the sound production and acoustic behaviour of the endangered O. croaticus during reproductive intersexual laboratory encounters, utilising an interdisciplinary approach. We also performed dissections and micro-computed tomography (μCT) scanning of the pectoral girdle to explore its potential involvement in sound production. Finally, comparative acoustic analysis was conducted on sounds produced by previously recorded soniferous sand gobies to investigate whether acoustic features are species-specific. The endemic O. croaticus is a soniferous species. Males of this species emit pulsatile sounds composed of a variable number of short (~15 ms) consecutive pulses when interacting with females, usually during the pre-spawning phase in the nest, but also during courtship outside the nest. Pulsatile sounds were low-frequency and short pulse trains (~140 Hz, <1000 ms). Male visual behaviour rate was higher when co-occurring with sounds and females entered the male's nest significantly more frequently when sounds were present. Characteristic body movements accompanied male sound production, such as head thrust and fin spreading. Furthermore, μCT scans and dissections suggest that O. croaticus shares certain anatomical similarities of the pectoral girdle (i.e. osseous elements and arrangement of levator pectoralis muscles) to previously studied sand gobies that could be involved in sound production. Multivariate comparisons, using sounds produced by eight soniferous European sand gobies, effectively distinguished soniferous (and sympatric) species based on their acoustic properties. However, the discrimination success decreased when temperature-dependent features (sound duration and pulse repetition rate) were excluded from the analysis. Therefore, we suggest both spectral and temporal features are important for the acoustic differentiation of sand gobies.

Effects of amplitude and duration of noise exposure on the hearing and anti-predator behaviour of common roach (Rutilus rutilus) and sand goby (Pomatoschistus minutus).

This study investigates whether an exposure to two different received sound pressure levels at equal cumulative energy affects anti-predator behaviour and auditory detection thresholds of common roach (Rutilus rutilus) and sand goby (Pomatoschistus minutus) differently. This was examined in regard to a vessel slowdown as a management strategy to decrease vessel noise impact on fishes. Using continuous broadband noise, we found significant temporary threshold shifts (TTS) in roach, with 11.9 and 13.4 dB at 250 and 1000 Hz respectively, for the louder exposure. In contrast, gobies exhibited a non-significant shift of 6.6 dB at 125 Hz. Group cohesion increased in roach exposed to an artificial predator in the control group, but not during noise exposures. Gobies showed an initial freezing reaction towards the predator stimulus remaining motionless regardless of treatment. Our results show that a reduction in vessel speed with a corresponding reduction in source level could mitigate the effects on the auditory senses of sensitive fish, but does not appear to have any mitigating effect on their noise-induced behavioural changes. Further studies should investigate the effects of multiple vessel passages, but also the ecological consequences of the described effects on hearing and behaviour at individual and population level.

Links between the timing of life history transitions and dietary and morphological variation during early life history in the sand goby, Pomatoschistus minutus.

Bipartite life histories involve a suite of morphological changes that support the pelagic to demersal transition and an expanded range of prey options and microhabitats. Pelagic individuals are thought to shift (settle) to their preferred benthic habitat at the earliest opportunity, once having attained a minimum level of morphological competency to access their new environment. In theory, early changes in larval morphology (collectively termed 'metamorphosis'), habitat, and diet - a measure of habitat-use - ought to be synchronous. Yet relationships may be decoupled by factors linked to behaviour, prey availability or morphological complexity, and few descriptions exist to allow such synchrony to be assessed. The sand goby, Pomatoschistus minutus, is a common coastal fish across north-western Europe, with a size at larval metamorphosis and settlement of around 10 and 16-18 mm SL, respectively. We sampled shoreline larval and juvenile populations to examine relationships between morphology, diet, and life stage. Prey diversity increased with body length. However, dietary change was clearest at 16-18 mm SL, with a reduction in calanoid copepods and shift to larger prey such as Nereis polychaetes and mysid and amphipod crustacea. Early growth in five prey capture and processing morphologies was rapid. Four of these showed a subsequent marked shift to slower growth, but none of these changes were aligned with size at metamorphosis and only that of mouth width coincided with the body size at settlement. Early life history in P. minutus appears geared towards a protracted morphological reorganisation prior to demersal life and an alternative suite of prey resources. Larval metamorphosis seems to be of limited consequence in this regard. Comparable studies of other Baltic Sea fishes would confirm whether these dynamics relate to shared environmental pressures or to factors intrinsic to P. minutus biology. This article is protected by copyright. All rights reserved.

Short and long-term temperature variations drive recruitment variability in marine and estuarine juvenile fishes

Understanding the long-term effects of climatic factors on key species' recruitment is crucial to species management and conservation. Here, we analysed the recruitment variability of key species (Dicentrarchus labrax, Platichthys flesus, Solea solea, Pomatoschistus microps and Pomatoschistus minutus) in an estuary between 2003 and 2019, and related it with the prevailing local and large-scale environmental factors. Using a dynamic factor analysis (DFA), juvenile abundance data were grouped into three common trends linked to different habitat uses and life cycle characteristics, with significant effect of temperature-related variables on fish recruitment: Sea surface temperature and the Atlantic Multidecadal Oscillation. In 2010, a regime shift in the North Atlantic coincided with a shift in the common trends, particularly a decline in P. flesus and S. solea trend. This work highlights the thermophilic character of fish recruitment and the necessity to investigate key biological processes in the context of species-specific responses to climate change.

An updated checklist of the Red Sea gobioid species (Teleostei: Gobiiformes), with four new records

An updated checklist and status assessment of the gobioid species (Gobiiformes) in the Red Sea is provided. Of the 162 species, 141 belong to the Gobiidae, nine to Microdesmidae, five to Xenisthmidae, six to Schindleriidae and one to Kraemeriidae. The Shrimpgoby (Cryptocentrus steinhardti) and the Sand Goby (Hazeus ingressus) are reported from Eilat, Israel and Abu Dabab, Marsa Alam, Egypt. Both species, which belong to Indo-West Pacific genera, were originally described from the eastern Mediterranean Sea and were unknown from the Red Sea so far. Records of these species are based on underwater photographs. Eviota pseudostigma, a species known from islands of the Western Indian Ocean, was photographed and collected from Mangrove Bay, El Quseir, Egypt, and represents a new record for the Red Sea. Eviota oculopiperita, described from the north-eastern Red Sea was found on the western side of the Red Sea. A new record of the microdesmid fish Gunnellichthys irideus, based on underwater photographs taken from the southern Egypt, is reported. Previous records of Paragobiodon echinocephalus from the Gulf of Aqaba are regarded as misidentification of P. modestus.

Chromosome Complement of Pomatoschistus marmoratus and Karyotype Evolution in Sand Gobies (Gobiidae: Gobionellinae)

The family Gobiidae constitutes one of the most diverse groups among teleost fish; some of its species are objects of aquaculture and fisheries. Despite many years of cytogenetic studies, the chromosome complements of many species of gobies remain unknown, and the trends of karyotypic evolution are poorly understood. Here I describe a previously unstudied karyotype of a widespread species from the group of sand gobies (Pomatoschistus marmoratus) and analyze the trends of karyotypic evolution of this group in comparison with other taxonomic groups of gobies from the Atlantic-Mediterranean and Ponto-Caspian regions. For P. marmoratus, the diploid number is 2n=46; it consists of 11 pairs of submetacentric chromosomes, 12 pairs of subtelocentric and telocentric chromosomes (NF=68). A comparative karyological analysis showed that the main trend in the karyotypic evolution of sand gobies differs from that of other groups of gobies and is associated with an increase in the number of chromosomal arms as a result of chromosomal rearrangements leading to a change in the centromere position. The results obtained contribute to understanding the role of chromosomal rearrangements in the evolution of Gobiidae and are of interest for further cytogenetic studies of this large family of fish.

Site-specific attachment of Anodonta anatina (Bivalvia: Unionidae) glochidia on two new fish hosts translocated in Lake Trasimeno (Italy)

To complete their life cycle, freshwater mussels of the order Unionida depend on fishes as hosts for their obligatory parasitic larval phase, the glochidium. Here we report the first documentation of gobioid fishes as hosts of glochidia of unionid mussels in the wild in Italy and in southern Europe (outside of the Danube drainage area). We also examined the pattern of the attached glochidia. A recent review reported 326 fish species as suitable hosts for unionids, but only eight (2.5%) of these were Gobioidei. Host identification and the documentation of their benefits or threats for the interaction of the mussels with their hosts is important for conservation of freshwater mussels. But the co-existence of mussels with non-native fish species is only poorly understood, including the compatibility of these two groups. Knipowitschia panizzae and Pomatoschistus canestrinii, two translocated sand gobies, were sampled in 2022 at the east shore of Lake Trasimeno (Italy). Two species of anodontine mussels were present at this locality, the native Anodonta anatina and the translocated Sinanodonta woodiana. Genetic data revealed that both sand gobies hosted glochidia only of A. anatina but not of S. woodiana, possibly because of seasonal bias. About 50% of the specimens of both fish species were infested. The paired fins were the most prominent targets. The examined individuals of both sand gobies carried only few glochidia (max. 5). Nevertheless, the two species showed a divergent pattern of glochidia attachment.

Deciphering Eurasian otter (Lutra lutra L.) and seal (Phoca vitulina L.; Halichoerus grypus F.) diet: Metabarcoding tailored for fresh and saltwater fish species.

Long-lived top predators shape biodiversity structure in their ecosystems and predator-prey interactions are critical in decoding how communities function. Studies on the foraging ecology of seals and Eurasian otters in Western Europe are outdated and most studies solely performed traditional hard part analysis. Molecular metabarcoding can be used as an innovative noninvasive diet analysis tool, which has proven efficient and complementary to hard part analysis, however, lacking application in the wider North Sea area. In this study, DNA from digesta, collected between 2014-2020, were used to identify fish species in the diet of 47 Eurasian otters, 54 harbour seals and 21 grey seals by applying a next-generation metabarcoding approach. A newly designed 16S rRNA primer, providing the best coverage of >130 local marine and freshwater fish species, was used to amplify prey DNA from seal scats and otter gut content sampled from the North Sea and regional freshwater bodies. Frequent fish species included tench, ninespine stickleback and white bream in otters; hooknose and common roach in grey seals and Pleuronectidae and sand gobies in harbour seals. Bipartite network analysis showed a strong overlap of harbour and grey seal diets. Otter diet intersected with both seal species in terms of freshwater species. This study provides new knowledge about dietary composition and community assemblage of fish prey in otters and seals in the North Sea and regional freshwaters, and a new molecular tool to elucidate predator-prey interactions and interspecies competition in complex and changing ecosystems under pressure from anthropogenic activities.

Male acoustic display in the sand goby – Essential cue in female choice, but unaffected by supplemental feeding

Many teleost fishes use acoustic and visual signalling during courtship. Such displays may convey information about body condition. Here we experimentally altered body condition of sand goby (Pomatoschistus minutus) males to examine effects on acoustic and visual courtship and subsequent spawning decisions. Over two weeks, males fed in excess were fed daily, whereas food-deprived males were fed once a week. Females only spawned with males that produced courtship sound. However, there were no treatment effects on the occurrence of spawning and males fed in excess did not invest more in visual or acoustic courtship than food-deprived males. That said, males fed in excess built more well-covered nests, with more sand piled on top, compared to food-deprived males. Male condition measured as lipid content differed significantly between treatments. However, only males fed in excess differed in lipid content from wild caught males, indicating that in nature, males are of similar condition to males in the low condition treatment group. Apart from the importance of courtship sound, the only male or female behaviour predicting reproductive success was if male displayed in the nest opening. Males often produce courtship sounds together with a visual display in this position. A female dark-eye display did not associate with reproductive success which, together with previous results, suggest a non-ornamental function of this trait. We conclude that male courtship sounds appear to be crucial in female mate choice, but the information content of the courtship sounds and how it relates to male condition remains elusive.

First Eastern Mediterranean Record of Xenoligophoroides cobitis, the Only Dactylogyrid Monogenean Infecting Mediterranean Gobies: Just Arrived or Missed the Boat?

Gobies and their ectoparasitic monogenean flatworms are promising models for species diversification because of their species richness. Recent decades have seen the discovery of several new species of Gyrodactylus (Monogenea: Gyrodactylidae) on European gobies, mostly in the sand goby lineage and especially in the eastern Mediterranean. However, the monogenean fauna of other gobies is much less understood. Therefore, we inspected five gobiid species (34 specimens, vouchered, with some representatives sequenced), sampled in Greece, for monogenean ectoparasites. Only specimens of the giant goby, Gobius cobitis, were infected; they harbored Xenoligophoroides cobitis (Monogenea: Dactylogyridae) on their gills. Here, we provide the first record from Greece, and the first ITS rDNA and COI sequences of the representative of this monotypic genus. Additionally, 28S rDNA was sequenced and compared with published data from across its known distribution, suggesting clinal variation. No sister-group for Xenoligophoroides could be proposed, nor could we explain the presence of a single known member of this genus on gobies, due to a lack of sequence data of closely related dactylogyrid monogeneans in public databases. Possible hypotheses include either the ancestral long-term presence on gobiids but “missing the boat” of the diversification events in the “Gobius-lineage”, or a recent host switch from a non-gobiid host.

Molecular, behavioural and morphological comparisons of sperm adaptations in a fish with alternative reproductive tactics.

In species with alternative reproductive tactics, there is much empirical support that parasitically spawning males have larger testes and greater sperm numbers as an evolved response to a higher degree of sperm competition, but support for higher sperm performance (motility, longevity and speed) by such males is inconsistent. We used the sand goby (Pomatoschistus minutus) to test whether sperm performance differed between breeding-coloured males (small testes, large mucus-filled sperm-duct glands; build nests lined with sperm-containing mucus, provide care) and parasitic sneaker-morph males (no breeding colouration, large testes, rudimentary sperm-duct glands; no nest, no care). We compared motility (per cent motile sperm), velocity, longevity of sperm, gene expression of testes and sperm morphometrics between the two morphs. We also tested if sperm-duct gland contents affected sperm performance. We found a clear difference in gene expression of testes between the male morphs with 109 transcripts differentially expressed between the morphs. Notably, several mucin genes were upregulated in breeding-coloured males and two ATP-related genes were upregulated in sneaker-morph males. There was a partial evidence of higher sperm velocity in sneaker-morph males, but no difference in sperm motility. Presence of sperm-duct gland contents significantly increased sperm velocity, and nonsignificantly tended to increase sperm motility, but equally so for the two morphs. The sand goby has remarkably long-lived sperm, with only small or no decline in motility and velocity over time (5 min vs. 22 h), but again, this was equally true for both morphs. Sperm length (head, flagella, total and flagella-to-head ratio) did not differ between morphs and did not correlate with sperm velocity for either morph. Thus, other than a clear difference in testes gene expression, we found only modest differences between the two male morphs, confirming previous findings that increased sperm performance as an adaptation to sperm competition is not a primary target of evolution.

Larval Ecology of Gobiid Fishes in a Subtropical Embayment: Environmental Preferences and Spatiotemporal Habitat Partitioning

Larval ecology of gobiid fishes in Xiangshan Bay of the east coast of China was examined from ichthyoplanktonic data collected during 10 weekly cruises in spring–early summer of 2015. Particular attention was given to their environmental preferences and spatiotemporal habitat partitioning. A total of 87, 007 gobiid larval individuals, distributed in 9 species, were collected. The thermal and salinity preferences of 6 of the 9 gobiid larvae have been determined using a quotient-rule analysis. This work filled some gaps in larval ecology of these poorly studied gobiids. Temporal succession in gobiid larvae composition was strongly evident. The bay ecosystem was mainly occupied by Asian freshwater goby Acanthogobius ommaturus, branded goby Chaeturichthys stigmatias and tank goby Glossogobius giuris, with preferences for temperature bellow 19°C during April to early May, while striped sand goby Amoya pflaumi and burrowing goby Trypauchen vagina, which preferred water temperature above 22°C, predominated the larval assemblage in early June. With respect to spatial distribution, relatively little variation was detected among species. Most of gobiid larvae exhibited little obvious habitat preference except pinkgray goby Amblychaeturichthys hexanema and A. ommaturus, which distributed preferably in the inner zone and mouth of the bay ecosystem, respectively. Water temperature was the major structuring factor of gobiid larvae assemblage structure in the bay. The gobiid larvae exhibited to be particularly susceptible to the rapid rising temperature shocks. Sharp decline in the total abundance of gobiid larvae was detected with each rapid heating process. In addition, significant shift in larval fish composition occurred following the process. The results suggest that pattern of temperature increase in spring and early summer plays a vital role in recruitment success of the gobiid larvae.

Влияние гидрологического и гидрохимического режимов на видовое разнообразие и биологические параметры бычковых рыб западной части Северного Каспия

Studies were carried out on the influence of the hydrological and hydrochemical regime on the species diversity and biological parameters of goby fish in the western part of the North Caspian in 2016-2018. It is shown that the species composition in these years was represented by 9 species, with a predominance of sand goby and bighead goby and with the increase in sea salinity, stenohaline fish began to appear: gray whip goby and Khvalyn goby, the number of the latter in catches increased in 2018 compared to 2017 by 16.8 times. The number and biomass of gobies in 2018 increased by 4 times compared to previous years and amounted to 2384 million copies, 16.807 thousand. t., respectively, as well as the improvement of their biological parameters, indicate the favorable state of the population, and hence the food supply for anadromous fish, in particular, sturgeon, semi-anadromous species, marine migratory herring.

Seed production and grow-out of sand goby (Oxyeleotris marmoratus) in Vietnam

This datasheet on Seed production and grow-out of sand goby (Oxyeleotris marmoratus) in Vietnam covers Identity, Overview, Case Study, Environmental Requirements, Growout Systems, Related Content, Further Information.

Dark-eyed females: sexually dimorphic prespawning coloration results from sex-specific physiological response to hormone exposure in the sand gobyPomatoschistus minutus(Gobiiformes: Gobiidae)

AbstractThe function and regulation of female nuptial colour signals are poorly understood. In fish, colour is often mediated by chromatophores, allowing for rapid and versatile signalling. Here, we examine a distinct but temporary black line around the eyes and snout (‘dark eyes’) displayed by female sand gobies before spawning and never observed in males. We investigate the regulatory mechanism of the display by analysing the number of melanophores in both sexes in vitro and their response to hormonal exposure. We also test the hypothesis that dark eyes serve an anti-glare function and focus the line of sight, by analysing the frequency, intensity and duration of the display in bright and dim light, with and without males present. We show that the sexes do not differ in terms of the number of melanophores, but that males and females respond in different ways to exposure to melanocyte-stimulating hormone, which has a stronger dilatory effect in females and results in a darker line. However, the darkness of the iris is not affected. Neither light levels nor the presence of potential mates affect the frequency of the dark eye display, but the display is longer lasting and more intense in the presence of smaller nest-holding males.

Restoring marine ecosystems: Spatial reef configuration triggers taxon‐specific responses among early colonizers

Abstract The longstanding debate in conservation biology on the importance of single large or several small (SLOSS) habitats for preserving biodiversity remains highly relevant, given the ongoing degradation and loss of natural habitats world‐wide. Restoration efforts are often constrained by limited resources, and insights from SLOSS studies therefore have important implications if restoration efforts can be optimized by manipulating the spatial configuration of restored habitats. Yet, the relevance of SLOSS for habitat restoration remains largely unexplored. Here, we report the effects of spatial reef configuration on early colonization of marine organisms after restoring boulder reef habitats. Reefs were restored in single large (SL) and several small (SS) designs in the western Baltic Sea, where century‐long boulder extraction has severely degraded large reef areas and likely exacerbated regional declines in commercially important gadoids (Gadidae spp.). We sampled the field sites using remote underwater video systems in a before‐after control‐impact (BACI) design and obtained probabilistic inferences on restoration and SLOSS effects from Bayesian hierarchical models. Probabilities of a positive restoration effect were high (&gt;95%) for gadoids, labrids and demersal gobies, moderate (60%–75%) for species richness and sand gobies, and low (&lt;5%) for flatfish abundance. Notably, gadoid abundance increased 60‐fold and 129‐fold on average at SL and SS respectively. The species composition at restored reefs deviated from control sites, mainly driven by large‐bodied piscivores. Spatial reef configuration had the strongest effect on small‐bodied mesopredators, including gobies, which were more abundant at SS and driving distinct species assemblages between the reef designs. In addition to providing suitable conditions for reef species, results suggest that SS can also benefit soft‐bottom taxa, possibly through a dispersed predator‐mediated effect relative to SL. Synthesis and applications. This study demonstrates that boulder reef restoration can strongly promote the abundance of exploited gadoids (e.g. Atlantic cod) and is therefore a promising management tool to support top‐down controls by predatory fishes in degraded marine systems. The higher abundance of mesopredators at reefs with a ‘several small’ configuration suggests that the SLOSS dilemma could have long‐term implications for trophic structure and resilience of restored habitats, and should therefore become an important facet within restoration strategies.