Boops boops, commonly known as the bogue, is a medium-sized marine fish belonging to the family Sparidae, native to the coastal waters of the eastern Atlantic Ocean and the Mediterranean Sea.[1][2] It features a slender, fusiform body with 3-5 golden longitudinal stripes along its sides and a distinctive black spot at the base of the pectoral fin, growing to a maximum length of 40 cm, though commonly reaching 20 cm.[1]This species is demersal to semi-pelagic, inhabiting depths from the surface to 350 m, typically over sandy, muddy, rocky, or seagrass-covered bottoms in subtropical and temperate waters.[1] Its distribution spans from southern Norway and the British Isles southward to Angola, including the Canary Islands, Cape Verde, Madeira, and the entire Mediterranean and Black Seas, with oceanodromous migrations.[1][2]Boops boops is gregarious, often forming schools and ascending to the surface at night, and occupies an intermediate position in the marine pelagic food web as an omnivore, primarily consuming benthic crustaceans, mollusks, and planktonic organisms.[1][3] Reproduction occurs via oviparity in open water, with the species exhibiting debated sexuality, reported as protogynous hermaphroditism or gonochoristic, reaching sexual maturity at around 13.6-16.6 cm in length and living up to 11 years.[1][4]Ecologically, B. boops serves as both prey for larger predators and a sentinel for environmental pollutants like microplastics due to its high ingestion rates.[3] It faces low exploitation rates in some regions, such as the Northern Aegean Sea, where fishing mortality is minimal (0.06 year⁻¹), contributing to its IUCN Least Concern status (assessed in 2009).[4][1]Of commercial significance, Boops boops is targeted by fisheries using handlines, gillnets, and purse seines, valued fresh, frozen, or as bait for species like sharks and tunas; it is also used in Mediterranean aquaculture feeds.[1][4][3]
Description
Physical characteristics
Boops boops exhibits a fusiform body shape, characterized by a streamlined, elongated form that is relatively low and slightly compressed laterally, with the anterior portion appearing subcylindrical in cross-section; this morphology facilitates efficient swimming and is well-suited to its schooling behavior in pelagic environments.[5] The body is covered in small cycloid scales, which are smooth-edged and provide flexibility during rapid movements. Along the lateral line, there are 69 to 80 scales, aiding in sensory detection of water movements and prey.[6]The species possesses large, prominent eyes, with the eye diameter typically greater than the snout length, a feature that contributes to the genus name Boops, derived from the Greek boōps meaning "ox-eyed," reflecting their bulging appearance adapted for enhanced vision in dimly lit waters.[7] The mouth is small and slightly oblique, equipped with a single row of sharp, incisor-like teeth in both jaws—approximately 10-12 in the upper jaw and 8-10 in the lower—that are pointed and slightly recurved inward, enabling the fish to grasp and hold onto slippery prey such as crustaceans.[5]The dorsal fin is divided into a spinous portion with 13-15 strong spines and a soft-rayed portion with 12-16 rays, while the anal fin features 3 spines followed by 14-16 soft rays; these fin configurations support agile maneuvering in schools and during foraging.[1] The body features a black spot at the base of the pectoral fin. Coloration patterns, including longitudinal stripes, are addressed in subsequent descriptions.[6]
Size and coloration
Boops boops typically attains a maximum total length of 40 cm, though individuals commonly reach 20 cm in length.[1]Adult specimens average around 60 g in weight, with a maximum reported weight of up to 986 g.[8][9]Growth in Boops boops follows the von Bertalanffy model, with parameters varying by location; in Saros Bay, the growth equation is given by L(t) = 27.9 \left(1 - e^{-0.21(t - (-1.57))}\right) cm, where L_\infty = 27.9 cm and K = 0.21 year^{-1}, reflecting moderate growth rates influenced by environmental factors such as water temperature and food availability in the northeastern Aegean Sea.[8] These parameters indicate that fish approach asymptotic length by around 6-7 years of age, with faster initial growth in warmer coastal waters.The coloration of Boops boops features a bluish-green back transitioning to silvery sides with golden reflections, providing camouflage in the variable light conditions of its coastal and pelagic habitats; there are 3-5 weak golden longitudinal stripes along the sides.[7] Juveniles exhibit paler overall tones with more pronounced darker stripes along the body, which may aid in avoiding predators in shallow, vegetated areas during early life stages.[7]Sexual dimorphism in Boops boops is minimal and varies by region; while some studies report males slightly larger in mean size, length at maturity differs, with females maturing at smaller sizes (around 12-13 cm) compared to males (around 15 cm). The species' reproductive strategy is debated, with reports of both protogynous hermaphroditism and a gonochoristic nature.[10][1]
Taxonomy and evolution
Etymology
The binomial name Boops boops originates from the species' initial description by Carl Linnaeus in 1758 as Sparus boops in the tenth edition of Systema Naturae.[2] In 1814, Georges Cuvier established the genus Boops with Sparus boops designated as the type species by tautonymy, thereby formalizing the current scientific name.[2]The generic and specific epithets "Boops" derive from the Ancient Greek term βοώψ (boōps), literally meaning "ox-eyed" or "cow-eyed," a reference to the fish's notably large eyes.[1]Common names for Boops boops include bogue, boce, and bogue bream, reflecting its recognition in various European fisheries and regional dialects.[1]
Classification and phylogeny
Boops boops belongs to the domain Eukaryota, kingdom Animalia, phylum Chordata, class Actinopterygii, order Spariformes, family Sparidae, genus Boops, and speciesB. boops.[11]The genus Boops, established by Cuvier in 1814, was long considered monotypic with B. boops as its sole species, but it now includes two recognized species: B. boops in the eastern Atlantic and Mediterranean, and B. lineatus in the western Indian Ocean.[12][13]The original description of Boops boops was provided by Linnaeus in 1758 under the name Sparus boops, with subsequent synonyms including Box boops (Linnaeus, 1758) and Box vulgaris (Valenciennes, 1830).[2][14]Phylogenetically, B. boops is embedded within the diverse family Sparidae, a clade of perciform-like fishes characterized by deep-bodied forms adapted to coastal environments. A 2022 molecular study using the mitochondrial control region (D-loop) identified three distinct lineages within B. boops across its range, indicating high genetic diversity and ongoing gene flow without a significant barrier between Atlantic and Mediterranean populations.[15]
Distribution and habitat
Geographic range
Boops boops is native to the eastern Atlantic Ocean, with its range extending from southern Norway southward to Angola, encompassing offshore islands such as the Azores, Madeira, the Canary Islands, Cape Verde, and São Tomé and Príncipe.[1] The species is also widespread throughout the Mediterranean Sea, including the margins of the Black Sea where it occurs, albeit less commonly.[1][16]Within its Atlantic distribution, Boops boops is particularly abundant from the Bay of Biscay to the Strait of Gibraltar, where it forms significant populations in coastal and shelf waters.[1] Northward occurrences become rarer, with only occasional records reported from the North Sea, Skagerrak, and Kattegat regions.[17] These northern sightings have been documented sporadically since the 20th century, including post-2000 observations in the southern North Sea.[18]Recent environmental changes, including warming waters associated with climate change, have been linked to potential range expansions for Boops boops into the North Sea, with projections indicating increased environmental suitability for the species in this area over the 21st century.[19]
Habitat preferences
Boops boops inhabits a wide depth range from 0 to 350 meters, though it is most commonly found between 0 and 100 meters, exhibiting a benthopelagic lifestyle where individuals remain closer to the bottom during the day.[20][15] This species prefers coastal and shelf environments in temperate to subtropical waters, often associating with structured habitats that provide cover and foraging opportunities.The preferred substrates for Boops boops include sandy and muddy bottoms, rocky areas, seagrass beds, and regions covered by macroalgae or seaweeds, which support its omnivorous feeding habits and offer refuge from predators.[20][21] These microhabitats are typically found along continental shelves and insular slopes, where the fish forms schools amid varied benthic features.Boops boops thrives in marine conditions, showing tolerance to fluctuations in coastal zones influenced by river inflows or upwelling. Water temperatures in its preferred range span 11.7 to 27.7°C, with an average of 17.8°C, aligning with its distribution in dynamic nearshore areas subject to turbulence from waves and currents.[20] The species exhibits diel vertical migration, descending to deeper waters near the substrate during daylight hours and ascending toward the surface at night to feed on plankton and other resources.[22]
Ecology and life history
Diet and feeding
Boops boops exhibits an omnivorous diet, primarily consisting of benthic invertebrates, planktonic organisms, and plant material. Studies in the Mediterranean Sea indicate that crustaceans, such as amphipods and decapods, form a significant portion of the diet, comprising approximately 49% of the food items, followed by porifera at 22.7%, coelenterates at 10.2%, seagrasses at 9.2%, and molluscs at 8.1%.[23] These proportions highlight a reliance on bottom-dwelling prey like annelids and molluscs alongside pelagic components, including copepods and siphonophores within the coelenterates.[24]The feeding strategy of B. boops is opportunistic, with the species displaying planktophagous behavior particularly at night when schools ascend to the surface. This nocturnal foraging is facilitated by the fish's large eyes, adapted for low-light detection, allowing efficient capture of plankton in dim conditions.[25]Ontogenetic shifts in diet occur, with juveniles showing a higher proportion of planktonic prey, such as coelenterates (up to 46.7% in smaller size classes of 9.5-11.4 cm), while adults incorporate more benthic items like crustaceans (increasing to 42.5% in larger individuals of 29.5-31.4 cm) and porifera. Prey size also increases with fish length, reflecting changes in foraging capabilities.[23]B. boops exhibits high levels of microplastic ingestion, with studies from the 2010s reporting an average of 3.75 microplastic particles per fish in 68% of examined gastrointestinal tracts from the Balearic Islands. More recent studies (2020-2023) report similar high ingestion rates, with microplastics found in up to 80% of specimens from various Mediterranean sites, primarily fibers and fragments.[26][27][28] This accumulation is attributed to the fish's planktivorous habits, as microplastics in the size range of 1 nm to 5 mm mimic plankton and are inadvertently consumed.[26]
Reproduction and development
Boops boops is reported to exhibit protogynous hermaphroditism in several studies, with individuals initially developing as females before transitioning to males at a size of approximately 17-21 cm total length; however, other studies suggest it is primarily gonochoric with only rare cases of hermaphroditism.[6][1] This sex reversal is evidenced by the predominance of females in smaller size classes and males in larger ones, with intersexual individuals observed during the transition phase.[6] The overall sex ratio is typically close to 1:1, though it can skew toward males during the spawning period in some populations.[29]The species is oviparous, releasing pelagic eggs into the water column during spawning.[30] Spawning occurs as a batch process, with multiple clutches of oocytes released over an extended period, typically from January to May in Mediterranean and eastern Atlantic waters, peaking in February-March.[31] In warmer regions such as the Canary Islands, the season aligns similarly but may extend slightly due to elevated temperatures.[6]Fecundity varies by population and female size, ranging from 36,600 to 445,200 eggs per female, with representative values of 50,000-100,000 eggs in mature individuals.[32] Size at first maturity is around 16.7 cm for males and 17.9 cm for females in Atlantic populations, though it can be smaller (12.5-15.8 cm) in some Mediterranean areas.[6][10]Following spawning, eggs develop into planktonic larvae that remain pelagic for 16-20 days on average before settlement.[33] Larvae settle at sizes of 1.5-2 cm total length, transitioning to demersal habitats and integrating into juvenile populations.[33] This brief pelagic phase supports localized dispersal while minimizing offshore losses in coastal environments.
Behavior
Social behavior
Boops boops exhibits a highly gregarious social structure, forming large schools that can number in the hundreds to thousands of individuals, primarily for predator avoidance and enhanced foraging efficiency. These schools are typically observed in mid-water pelagic zones during the day, with the fish ascending closer to the surface at night, possibly to exploit planktonic resources.[1][34]Juveniles display age-specific grouping patterns, forming dense shoals in shallower coastal littoral areas, particularly at night in anthropogenically modified habitats such as those near urban shorelines in the Mediterranean. These juvenile aggregations show seasonal abundance variations but remain consistent in their nocturnal timing, independent of lunar phases, and occur in smaller, more localized groups compared to adult formations.[35]In terms of interspecific interactions, B. boops commonly associates with other members of the Sparidae family, such as Diplodus vulgaris and Sarpa salpa, in shared coastal nursery habitats where juveniles co-occur and exhibit diet overlap, leading to potential competition for resources like crustaceans and mollusks. Adults participate in mixed pelagic groups with similar sparids.[36][1]
Movement patterns
Boops boops exhibits pronounced diel vertical migration, remaining at greater depths during the day and ascending toward the surface at night to access prey resources such as plankton. This behavior is observed in both juveniles and adults across its range in the eastern Atlantic and Mediterranean, where schools typically occupy mid-water columns by day and move into shallower, surface-oriented positions (<10 m) nocturnally to exploit vertically migrating zooplankton.[1][7][37]Seasonally, the species undertakes inshore-offshore shifts, with adults forming large shoals that migrate to deeper offshore waters (>100 m) during winter and spring for spawning, which peaks between January and May. In contrast, during summer months, groups approach shallower coastal areas, aligning with shifts in foraging opportunities over varied bottom types like sand, rocks, and seagrass beds. Latitudinal migration remains limited, consistent with its oceanodromous nature, though genetic studies reveal no strong barrier to gene flow between Atlantic and Mediterranean populations, facilitating subtle range connectivity without extensive poleward displacements.[15][31][1]
Parasites and diseases
Parasite species
Boops boops harbors a diverse community of metazoan parasites, with more than 14 species documented across various studies, primarily comprising platyhelminths, nematodes, and crustaceans.[38] In 2024, a new genus and species of monogenean, Polyopisthocotyla bouops (Polyopisthocotylea: Microcotylidae), was described from the gills of B. boops in the western Mediterranean.[39] Among these, digenean trematodes represent the most prevalent group, with at least eight species recorded, including Wardula bartolii (Mesometridae), a species specific to sparids in the NE Atlantic, and Lepidapedon spp. (Lepidapedidae), which infect the intestinal tract.[40][41] Other notable digeneans include Lecithaster confusus, Aponurus laguncula, and Accacladium serpentulum, often as accidental infections.[40]Nematodes are less diverse, with a single primary species, Anisakis simplex (Anisakidae), commonly found in the viscera and serving as a zoonotic concern due to its larval stages.[42]Crustacean parasites include five species of isopods, such as Ceratothoa oestroides and Ceratothoa capri (Cymothoidae), which attach to the buccal or branchial cavities and can cause tissue damage, including gill erosion and inflammation.[43] Prevalence of digenean infections typically ranges from 20% to 40% in examined hosts, varying by location and host condition, while isopod infestations are lower, around 9-10%, but lead to notable branchial pathology.[44][43][45]Many of these parasites, particularly digeneans, exhibit complex life cycles involving intermediate hosts like crustaceans and mollusks, which are ingested by B. boops during feeding, facilitating transmission.[46] Parasite diversity and composition show regional variation, with higher species richness (up to 37 metazoans) in Mediterranean populations compared to fewer records in the Atlantic, reflecting differences in prey availability and environmental factors.[47][46]
Environmental influences on parasites
The Prestige oil spill in 2002 significantly altered metazoan parasite communities in Boops boops along the affected Galician coast, leading to lower species richness and diversity compared to unaffected sites. These changes were attributed to the spill's impact on intermediate hosts, such as benthic invertebrates, disrupting the life cycles of complex parasites like digeneans, while favoring simpler ectoparasites. Follow-up assessments in 2003–2005 confirmed a persistent decrease in community diversity and an increase in dominance by certain taxa, reflecting ongoing environmental stress on the host and its ecosystem. By 2014–2015, approximately 12–13 years post-spill, univariate and multivariate analyses indicated partial ecological recovery, with parasite community structure approaching pre-spill conditions, though some long-term shifts in composition remained detectable.[48][49]Recent studies from the 2020s have documented high microplastic ingestion in B. boops across Mediterranean and Atlantic waters, correlating with physiological stress and potential immune suppression in affected fish. Microplastics can indirectly elevate parasite loads, including nematodes, by compromising host immunity and altering gut microbiomes, as observed in experimental exposures and field surveys of marine teleosts. In B. boops, such pollution may exacerbate vulnerability to endoparasites, though direct causal links require further investigation.[28][50]Ocean warming associated with climate change is projected to enhance parasite transmission in B. boops by promoting range expansions of intermediate hosts and vectors, increasing overlap with the fish's distribution in the Mediterranean and eastern Atlantic. Elevated temperatures can accelerate parasite development rates and survival of free-living stages, potentially leading to higher infection intensities for trophically transmitted species. These effects underscore the role of B. boops parasites in signaling broader climatic disruptions to marinefood webs.[51]Parasite communities in B. boops serve as effective bioindicators for monitoring ecosystem health, with shifts in diversity and abundance providing early warnings of pollution and habitat degradation. Post-spill trends in this species have demonstrated the utility of such metrics for assessing recovery trajectories and informing conservation efforts in coastal environments.
Conservation and human relations
Conservation status
Boops boops is classified as Least Concern (LC) on the IUCN Red List, with the assessment conducted on 14 August 2009 (published 2014) and annotated as needing an update; no subsequent global assessment has been conducted, though recent data indicates declining landings that may affect stability as of 2025.[52][1] This status reflects its widespread distribution across the eastern Atlantic and Mediterranean Sea, where it remains common without evidence of significant population declines at the species level.[53]Population trends for Boops boops vary regionally; while generally considered stable per the IUCN assessment, local stock assessments indicate overexploitation and declining catches in some areas, such as the western Algerian coast and Egyptian Mediterranean waters, with no major declines reported in others like the Northern Aegean Sea. The species has medium resilience with a minimum population doubling time of 1.4–4.4 years.[1][54][55][4] Minor threats include overfishing and bycatch in commercial fisheries, as well as habitat degradation from coastal development and pollution, though these do not currently limit populations at a species-wide level.[53] Accumulation of microplastics in individuals has been documented, particularly along Mediterranean coasts, but this is not considered a primary driver of population-level impacts.[56]The species occurs within several Marine Protected Areas (MPAs) in the Mediterranean, such as the Gulf of Patti near Cape Milazzo in Italy, where monitoring supports its stable presence amid localized conservation efforts.[28] Overall, Boops boops faces low extinction risk due to its abundance and adaptability, with ongoing fisheries management helping to mitigate pressures.[1]
Fisheries and other uses
Boops boops is primarily targeted in commercial fisheries across the Mediterranean Sea, where it is captured using purse seines, bottom trawls, gillnets, and beach seines.[57] These methods often yield the species in association with other pelagic fish, contributing to multispecies catches in coastal and shelf waters.[58] Annual landings in the Mediterranean averaged approximately 28,800 tonnes between 2009 and 2011, representing about 3% of total regional fish landings; more recent data indicate lower totals, with an average of 18,333 tonnes (2018–2020) across the GFCM area, though variability persists in country-specific catches such as around 5,000 tonnes per year in Algerian waters and 2,310 tonnes in Turkish waters in 2022.[59][60][61][62] The fish is typically marketed fresh or frozen for human consumption.[1]In recreational fisheries, Boops boops serves as a gamefish targeted by anglers, particularly in coastal areas of the Mediterranean, due to its abundance and accessibility.[1] It is also utilized as bait for capturing larger predatory species.[1]Other uses include its role in traditional Mediterranean cuisine, where it is prepared pan-fried, broiled, or baked.[1] Minor trials in aquaculture have explored its potential, though commercial production remains limited; the species often aggregates around offshore fish cages, potentially influencing local wild populations. Fisheries management in EU waters involves quotas and total allowable catches (TACs) under the Common Fisheries Policy, coordinated through the General Fisheries Commission for the Mediterranean (GFCM) to regulate exploitation. Boops boops frequently appears as bycatch in purse seine and trawl operations targeting tuna and other pelagics.[58]