Ichthyofauna associated with a no longer standing decommissioned oil plataform in the Tropical Eastern Pacific (4°S, Peru)

Diego Cuba^1,2 and Bernabé Moreno^1,2,3,4

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Abstract​

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Introduction​

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Seabed resources account for one-third of global oil extraction, which has instigated the construction and deployment of up to 12,000 oil-and-gas platforms around the world’s continental shelves (Pulsipher, Daniel, 2000; World Ocean Review, 2014; Ars, Rios, 2017) where about 95% are fixed-type jacket platforms (Fu, 2018). These oil rigs extend along the entire water column from the surface to the seabed, conforming unique artificial habitats for a myriad of marine organisms, where fish can yield the highest biomass (Claisse et al., 2014; Torquato et al., 2018; Meyer-Gutbrod et al., 2019; van Elden et al., 2019; Coolen et al., 2020; Lemasson et al., 2021). The termination of operation and dismantling of the jacket structure is part of the decommissioning phase, where five primary decommissioning strategies exist for coastal oil platforms: i) leaving the platform in place, ii) complete removal of the structure (inevitably leading to the elimination of the epibenthic and associated fauna); and the so-called “reefing” alternatives which includes iii) topping (top portion removed to > 20 m subsurface and lower portion remains standing), iv) toppling (platform toppled over in same location), and v) relocation followed by toppling (Bull, Love, 2019).

Oil platforms provide numerous ecosystem services since they function as artificial reefs, harbouring complex ecological communities that most time include species of commercial interest (Ajemian et al., 2015; McLean et al., 2019; Todd et al., 2021; van Elden et al., 2022). These platforms also provide opportunities for ecotourism activities such as marine wildlife watching, spearfishing, and recreational diving (Shani et al., 2012; Lemasson et al., 2021). Because of their significant ecological, fishing, and tourism potential as “novel” ecosystems, globally, there is pressure to recognise and highlight the ecological and economic value of standing platforms and thus opt for alternative strategies other than complete removal during the decommissioning phase (van Elden et al., 2019; Lemasson et al., 2021). When permitted, these platforms are popular sites for recreational and artisanal fishing (Dugas et al.,1979; Jablonski, 2008). An illustrative example of the overlap between habitat provision, ecotourism, and fishing activities was the decommissioned oil rig MX-1, located 3 km off the coast of Los Órganos, Piura (Jacinto et al., 1996), lying on the seafloor at a maximum depth of 60 m. Around the MX-1, local artisanal fishermen would employ traditional rafts called “tumpis”, declared as cultural heritage (Hooker, Ubillus, 2011; MINCUL, 2018).

Globally, previous research on platform-associated fauna has predominantly focused on biofouling (benthic) assemblages according to Coolen et al. (2020), and ichthyofauna (Seaman et al., 1989; Fabi et al., 2004; Consoli et al., 2013; Torquato et al., 2018; Schulze et al.,2020; Todd et al., 2021; Sih et al., 2022; Tothill et al., 2024). Such studies are scarce or unreported along the Peruvian coastline, with only one accessible study (Hooker, Gonzales, 2012). Constituting 19% of west South America, the Peruvian coastline (> 3000 km from 3.5–18°S) is characterised by intensive coastal upwelling which, coupled with various environmental and biological factors, contributes significantly to the high productivity of the Peruvian marine ecosystem (Zuta, Guillén, 1970; Gutiérrez et al., 2016; Ibanez-Erquiaga et al., 2018). The upwelling processes increase nutrient availability, fostering large biomass, and therefore large-scale fisheries (Chavez et al., 2008). The northern Peruvian coast harbours 70% of Peru’s marine biodiversity (Hooker, 2009;Hooker et al.,2011; Hooker, Ubillus, 2011). This regional diversity is distributed along two distinct biogeographic zones: the Panamic Province (22°N–4.5°S), the Peruvian Province (5.5°–42° S) (Spalding et al.,2007; Chaigneau et al., 2013; Hooker et al., 2013; Ibanez-Erquiaga et al., 2018; Vermeij et al. 2024); with a transition zone (ecotone) in between (~4.5–6°S) (Fig. 1). The coastline of Piura region in northern Peru spans around 400 km (4.08–6.38°S) where 90 jacket-type oil rig structures in different operational stages (exploration, exploitation, or abandonment) rest on the seafloor.

Due to the limited baseline information for ichthyofauna associated with artificial reefs in the Tropical Eastern Pacific, this study aimed to assess the composition and vertical structure of the fish associated with the oil platform MX-1, during the austral spring of 2022. Our study also aimed to determine whether the vertical structure of the platform provided favourable conditions for hosting fish species from various biogeographical regions, and also explore the role of the oil rig as a biodiversity facilitator with potential indirect benefits to users of the sea including artisanal fishermen and ecotourism agencies.

Material and methods

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Study area. The decommissioned platform MX-1 was located 3 km off the coast of Los Órganos, Piura, Peru (4.16°S, 81.16°W), next to the recently established Reserva Nacional Mar Tropical de Grau (Fig. 1) (Cutipa-Luque et al., 2020; MINAM, 2023, 2024a). This region lies at the confluence of the Panamic and transition zones, influenced by the interaction of the cold, nutrient-rich Humboldt Current from the south, and the warm Equatorial Counter current from the north, driving high productivity and seasonal oceanographic variability. The regional climate is semi-arid. Rainfall is typically low, except during El Niño episodes, which significantly alter oceanographic conditions, mixing much warmer, more oxygenated and less nutrient-rich waters (Escribano et al., 2004; Guevara, Milla, 2007). The platform was a 65 m high metal structure with seven levels, six of which were submerged at depths of 5, 15, 26, 37, 49, and 60 m of sea water (Petro-Tech, 2009). The platform provided complex hard-substrate habitats in an area dominated by soft-bottom sediments. Removal operations using the topping strategy began in 2023 in accordance with Directorial Resolution R.D. Nº079-2022-MINEM/DGAAH (MINEM, 2022).

FIGURE 1| Study area off the northern coast of Peru in the southeastern Pacific. The decommissioned MX-1 platform was located approximately 3 km offshore from Los Órganos, Piura, Peru (4.16° S, 81.16°W), adjacent to the recently established Reserva Nacional Mar Tropical de Grau (RN MTG; Cabo Blanco–El Ñuro polygon). The inset map shows the boundaries of two Large Marine Ecosystems (LMEs): the Pacific Central American Coastal LME (PACA) LME and the Humboldt Current (HC) LME. Also depicted are the two marine biogeographic provinces and the transitional ecotone (~4.5–6°S) referenced in the text: the Panamic Province (22°N–4.5°S, also referred to as the Tropical Eastern Pacific Marine Province, TEP-MP), and the Peruvian Province (5.5°–42°S, also known as the Warm Temperate Southeastern Pacific, WTSP-MP). Polygons of the RN MTG were obtained from https://geo.sernanp.gob.pe/visorsernanp/, marine regions from https://www.marineregions.org/, and country polygons from https://earthworks.stanford.edu/catalog/. Map produced in QGIS 3.28.12.

Underwater visual censuses. Six open-circuit SCUBA dives were carried out over six days during austral spring (October 2023). The structure was vertically divided a priori into five depth strata/ranges: 0–5 m, 5–10 m, 10–20 m, 20–30 m, and 30–40 m (as described by Hooker, Gonzales, 2012; Todd et al., 2018). Due to safety reasons in diving procedures (e.g., avoidance of ‘deep-air diving’) and logistical constraints, the deepest strata between 41–60 m was not surveyed. The descent was made along the outer periphery of the platform to prevent disturbing fish on the way down. The deepest stratum 30–40 m was surveyed first (Pyle, 2019) in such a way that the bottom time at maximum depth did not reach the no-decompression limit (NDL 8 min at 42 m) (PADI RDP recreational dive planner table). The visual census adopted the roving-diver survey technique by Rassweiler et al. (2020), a way to rapidly sample the entire fish assemblage at any given site, recording all fish encountered where divers swam slowly from vertical pilings, conducting a square sweep within the structure and gradually ascending while observing the fish associated with the substrate and the water column. The area delimitation was adapted from the fixed-point methodology considering a field-of-view of ~6 m² approximately where fish were identified and counted accordingly (Cappo et al., 2006; Hooker, Gonzales, 2012; Lindfield et al., 2014; Thurstan et al., 2014; Caldwell et al., 2016). Five replicate counts were conducted per depth stratum, resulting in a total estimated surveyed area of ~150 m². Supporting footage recordings were taken with a GoPro Hero 6 action camera and two SOLA 2000-lumen video lights. Data collection was supported by a visual record of identification and abundance recommended by Seaman et al. (1989) and Rilov, Benayahu (2000). All dives were logged accordingly using the SciDive record forms proposed by Moreno (2020). The species identification was cross-validated by revisiting the supporting footage and using relevant literature (Chirichigno, Veléz, 1998; Humman, DeLoach, 2003; Robertson, Allen, 2015; Siccha-Ramirez et al., 2022; Fricke et al., 2018) and consultation with ichthyologists with experience on the ichthyofauna of the region. Once identification and counts were validated, the abundances were tabulated and organised by species and depth.

Fish assemblage diversity indices and functional strategies. Fish abundance and alpha diversity were calculated per depth strata. To describe the fish diversity in terms of richness, Margalef’s (1958) index was used. Other indices including Shannon-Weaver (Shannon, Weaver, 1949) and Pielou’s evenness (Pielou, 1981) were employed to compare fish assemblages between depths. The Chao-1 index was used to estimate total species richness (S_est) and compared it with the observed (S_obs) (Chao, 1984; Chao et al., 2014). The SIMPER (similarity percentage) routine was applied to identify which taxa were primarily responsible for the observed differences between groups of samples (Clarke, 1993). To identify spatial variation in species composition beta diversity as proposed by Whittaker (1960) was used. Additionally, a cluster analysis was employed using Sorensen dissimilarity distance (Sorensen, 1948). All calculations were done in PAST 4.12 (Hammer et al., 2001). The functional strategy of each species or taxon was described using five categorical traits based on the feeding and locomotion of species, namely: body shape, swimming type, diet, habitat, and trophic niche; all of which are crucial for determining their role in the marine ecosystem (modified from Torquato et al.,2018; Froese, Pauly, 2023). Descriptions of each categorical trait are provided in Tab. 1. Abundance data were log-transformed to meet the assumptions of normality, which was evaluated through a quantile-quantile (q-q) plot of residuals and the Shapiro-Wilk test, while homogeneity was assessed through residual vs. predicted values plot. One-way PERMAVOVA was used to identify differences among depths. Non-metric multidimensional scaling (nMDS) was used to represent the pairwise dissimilarity of fish assemblage between depths in a two-dimensional space. Statistical analyses were computed using the software PAST 4.12 (Hammer et al., 2001).

TABLE 1 | Functional traits of fish species analysed for their ecological roles and strategies.

Trait	Description
Body shape	Describes the physical form and structure of the fish, which can influence hydrodynamics, manoeuvrability, and energy efficiency.
Swimming type	Refers to the method of locomotion used by the fish.
Diet	Details the feeding habits of the fish. Diet influences the fish’s role in the ecosystem and its interactions with other species.
Habitat	The environment where the fish lives.
Trophic niche	The role of the fish in the food web.

Oceanographic data. Temperature and salinity along the water column were obtained with a hand-held SonTek CastAway-CTD attached to the diver’s harness D-ring during the dive (ACT, 2007; Patterson et al., 2011). Based on these casts, the predominant water masses were identified following the classification of Zuta, Guillén (1970).

Results​

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Zonation of fish assemblages: abundance, richness, and diversity. Overall, a total of 7,969 fish were counted, which belonged to 27 species distributed within 13 families. Among these, eight (30%) commercially targeted species were recorded (Tab. 1). The Pomacentridae, Serranidae, and Carangidae were the richest families with five species each, followed by Blenniidae with three species. Fish were mostly aggregated between the crossbeams and pilings of the rig (Figs. 2, 3).

FIGURE 2| Schematic of the MX-1 oilrig depicting the vertical distribution of fish according to the surveyed depth strata. Also shown are the relative dominance of the ichthyofauna and nMDS calculated from the survey observations (austral spring, October 2022). One-way PERMANOVA showed a significant difference in fish composition which is represented by letters.

FIGURE 3| Dominant species around MX-1. A. Peruvian rock seabass Paralabrax humeralis, B. Pacific creole-fish Cephalopholis colonus (n=261) was most abundant between 10–20 m, actively swimming against the current in search of food and exhibiting reproductive behaviour, C. school of Chilean jack mackerel Trachurus murphyi, D. Longfin yellowtail Seriola rivoliana, E. Peruvian rock seabass Paralabrax humeralis (n=761) dominated between 30–40 m depth forming dense aggregations among the structure’s pilings, F. Panamic sergeant major Abudefduf troschelii (n=80) was mainly observed at 5 m depth associated with the most diverse substrate where it coexisted with a variety of other reef fish species near crossbeams.

Species dominance varied according to depth strata. The most abundant taxa were the Peruvian rock seabass Paralabrax humeralis (Valenciennes, 1828) (n = 761), the Pacific creole-fish Cephalopholis colonus (Valenciennes, 1846) (n = 261), the Panamic sergeant major Abudefduf troschelii (Gill, 1862) (n = 80), the Chilean jack mackerel Trachurus murphyi Nichols, 1920 (n = 73), and the longfin yellowtail Seriola rivoliana Valenciennes, 1833 (n = 21) (Fig. 3). The shallowest stratum (5 m) showed the highest taxonomic richness (n = 19) (Fig. 2) (Tab. S1), while the two deepest strata (20–40 m) showed the highest abundance with 351 and 442 counts, respectively. In terms of biogeographic affiliation, 20 species belonged to the Panamic Province, three to the Peruvian Province, and the remaining four are commonly distributed in both provinces. The Equatorial Surface Water (ESW) and Cold Coastal Water (CCW) were identified from the average oceanographic vertical profile, including temperature and salinity (Tab. S2).

The nMDS based on fish composition showed a vertical zonation in fish composition, that is, a clear separation by depth, although the two shallowest strata (0–10 m) were the most similar (Fig. 2). Beta diversity indicated a differentiation between fish composition along the water column (Tab. S3). Sorensen clustering showed a relationship among 5–10 m and 20–30 m (Fig. S4). The dominance of P. humeralis was recorded between 20–40 m, while C. colonus was dominant between 5–20 m (Tab. S5). The epibenthic fish assemblages were dominated by different species depending on the depth strata (Fig. 2). The number of species was lower as depth increased, indicating that the shallower strata supported a greater number of species. The total number of individuals and dominance was higher with increasing depth; thus, evenness and equitability were higher at shallower depths, suggesting a more even distribution of abundance among species. Shannon and Margalef diversity indices exhibited a downward trend as depth increased, with the highest diversity at 5 and 20 m, suggesting that the assemblage composition was more heterogeneous towards the shallows. The estimated species richness using the Chao-1 index tended to increase with decreasing depth, suggesting that there may be more species present than observed directly at all depth strata. The alpha diversity and beta indices results are shown in Tabs. S1, S3.

Functional strategies. Most species were carnivorous (n = 14), followed by omnivores (n = 6) and planktivorous (n = 4) (Tab. S6). Carnivores were numerically dominant at all depths, with higher dominance at the deepest range surveyed (30–40 m), where other groups were scarce. Both carnivores and omnivores had a higher number of species observed from 5–20 m. Fish that feed on sessile invertebrates, such as the three-banded butterflyfish Chaetodon humeralis Günther, 1860, were only recorded at 40 m. Planktivorous fish were found across all surveyed depth ranges. The highest trophic niche belonged to the longfin yellowtail S. rivoliana (4.5 ± 0.7), while the lowest (2.0 ± 0.0) was shared by three species: the beau brummel Stegastes flavilatus (Gill, 1862), the brassy chup Kyphosus vaigiensis (Quoy & Gaimard, 1825), and the barnaclebill blenny Hypsoblennius brevipinnis (Günther, 1861). The distribution of swimming types among these species is detailed in Tab. S7. The observed swimming patterns reflected functional strategies related to habitat occupation and feeding. Most species exhibited subcarangiform swimming, predominantly among carnivores and omnivores inhabiting mid and deep waters. Carangiform and labriform behaviours were displayed by species from different trophic levels and habitats, while Chaetodon humeralis, the only species exhibiting balistiform swimming, was exclusively recorded at 40 m, aligning with its feeding preference for sessile invertebrates. These differences in locomotion may influence the vertical distribution of species and their ecological roles within the assemblage structure.

Discussion​

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Fish diversity and habitat conditions. Globally, numerous studies have extensively documented the composition of ichthyofauna associated with oil rigs (Barker, Cowan, 2018; Torquato et al., 2018; Bull, Love, 2019; Love et al., 2019; McLean et al., 2021). The submerged sub-structures of the oilrigs which include crossbeams, vertical pilings, and cryptic habitats such as crevasses enhance habitat complexity, potentially leading to high diversity and abundance in reef fish populations (Friedlander et al., 2014; Bull, Love, 2019). Standing decommissioned platforms, typically host higher species richness compared to toppled and cut-off structures (Bull, Love, 2019). Recent research efforts continue to investigate the role of oil platforms as artificial reefs and their impact on fish diversity. Nevertheless, the effect of these structures varies across different oceanic regions, influenced by unique environmental and ecological conditions. For example, between 12 to 26 fish species were identified in three oil rigs further north MX-1, where the scissortail damselfish Azurina atrilobata Gill, 1862andthe Pacific creole-fish C. colonus were the most abundant (Hooker, Gonzales, 2012). Our study identified and reported the vertical zonation of fish assemblages, the dominance of C. colonus, and 16 species in common with the abovementioned study, primarily associated with the Panamic region. This can be attributed to similar oceanographic and habitat conditions in both study areas. Specifically, platform MX-1, which was located further south with greater depth, may facilitate the colonisation of species affiliated with the Peruvian and Panamic regions. This facilitated the recruitment of a greater diversity of species, even under fishing pressure. The occurrence of commercial species across multiple oil platforms indicates that these taxa are not confined to a single location (Hooker, Gonzales, 2012), suggesting broader adaptability to various marine environments. The richness of fish taxa around oil rigs can be different depending on the marine region, for instance, 41 fish taxa have been recorded in the Mediterranean Sea (Consoli et al., 2013), 40 species in oilrigs off southern California (Helvey, 2002), and 83 species associated to the Al Shaheen oil field in the Persian Gulf (Torquato et al.,2018).

Surveys around Australian oil rigs have identified critically endangered species, unique fish behaviours, potential new fish species, and diverse assemblages, comprising a total of 117 fish taxa (McLean et al.,2021). In contrast, our study identified only 27 species, indicating a comparatively lower richness than reported for similar structures worldwide. This difference may reflect regional biogeographic patterns, the limited temporal extent of data collection, and methodological constraints. Natural rocky reefs in the area have reported up to 82 fish species, representing a highly diverse assemblage (Zavala et al., 2025). In contrast, kelp forest ecosystems, characteristic of the Peruvian upwelling system, have recorded 25 fish species (Cuba et al.,2022). Furthermore, Isla Foca, the closest island further south to the study site, hosts 43 fish species (Hooker et al., 2012). Compared to these ecosystems, the 27 species documented at MX-1 suggest an intermediate richness level. Although lower than the diversity found in rocky reefs and Isla Foca, the artificial structure hosted more species than temperate kelp forest habitats at higher latitudes in Peru. Highlighting its potential role as a complementary habitat within the local seascape. According to the Chao1 index, the estimated taxa richness (S_est) could be as high as 55 (twice the S_obs), which would represent 45% of the 82 species of coastal fish richness reported in marine rocky reefs near the zone (Zavala et al., 2025).

Recent research along the central coast of Peru reported 18 fish species associated with an artificial port terminal, revealing a vertical stratification in fish distribution and a predominance of carnivorous species across depth zones (Pacheco et al., 2023). Among them, key commercial species such as the lorna drum Sciaena deliciosa (Tschudi, 1846) were identified, reinforcing the role of artificial structures in attracting valuable biological resources. These findings also suggest possible fish movements between natural and artificial habitats (Caldwell, Gergel, 2013), underscoring the importance of further research into connectivity, ecological function, and implications for fisheries management.

The Peruvian rock seabass P. humeralis and the Pacific creole-fish C. colonus exhibited depth-dependent variations (Fig. 2). These patterns closely align with thermal gradients, as temperature generally decreases with depth, influencing key physiological aspects such as metabolism, growth, and behaviours including reproduction and aggregation (O’Gorman et al., 2016; Boltaña et al.,2017; van Denderen et al., 2020). Such vertical distribution likely reflects a behavioural response to both the physical stratification of the water column (Coles, Tarr, 1990; Martin, Lowe, 2010) and biological aspects such as prey availability (Torquato et al., 2018). Traditionally, this pattern is attributed to reduced energy availability, increased pressure, and lower temperatures with greater depth. However, the expected relationship between richness and depth may also be influenced by higher photosynthetic production rates in the uppermost layers (Torquato et al.,2018; Harvey et al., 2021).

Biogeographic affiliations. The MX-1 oil platform was located between the Panamic Province and the transition zone of the Tropical Eastern Pacific, a region shaped by the dynamics of the Humboldt Current and ENSO variability (Ibanez-Erquiaga et al., 2018; Hooker, 2009; Brochier et al., 2013). We identified 23 reef fish species that were using the platform as habitat, including 20 from the Panamic Province and 3 from the Peruvian Province. This suggests MX-1 acted as a refuge of biogeographical connectivity, supporting ichthyofauna species from both northern and southern assemblages. Intriguingly, the different phases of El Niño Southern Oscillation (ENSO) introduce dynamicity to the distribution of the species, potentially modulating community composition across planktic, benthic, and specifically, fish biota (Tarazona et al., 2003; Hooker, 2009; Miloslavich et al., 2011).

The reported occurrence of Chirodactylus variegatus (Valenciennes, 1833), 150 km north of its previously reported range (Chirichigno, Vélez, 1998), may be associated with La Niña negative anomalies condition during 2022 (ICEN = -1.39) (Li et al., 2022; MINAM, 2024b). Similarly, the abundance of P. humeralis has shown sensitivity to ENSO phases (Adams, Flores, 2016), underscoring the importance of monitoring indicator species. By systematically recording fish assemblages and monitoring the abundance of identified indicator fish species in artificial reefs in the Tropical Eastern Pacific, we can discern the impacts of ENSO phenomena on the dynamics and management of fisheries’ target species.

Physical oceanographic processes influence the distribution of fish larvae across various spatial scales (Victor, Wellington, 2000; Green et al., 2015; Álvarez-Noriega et al., 2020). While our study did not assess larval dispersal, the high abundance of juvenile individuals of commercially targeted species observed around the platform suggests that artificial structures may play a role in local recruitment dynamics. Previous studies have indicated that offshore platforms can act as focal points for larval settlement and potential sources of ecological spillover, i.e., outward net emigration of juveniles, subadults and adults from the protected areas (Love et al., 2006; Buxton et al., 2014; Pondella et al., 2015). However, without ichthyoplankton surveys or biophysical dispersal models, the extent to which the platform influenced larval transport in the study area remains uncertain. Future research incorporating such methodologies would provide valuable insights into the role of artificial structures in larval retention and dispersal along the Peruvian coast.

Oil rigs have been reported to work as a driver to smooth the dispersion and colonisation of fish by increasing the availability of preferred habitats and ecological connectivity within the populations (Mclean et al.,2022; Watson et al.,2023). Oil platforms such as MX-1 may potentially enhance connectivity across seascapes by facilitating vertical and horizontal fish movement, as has been documented in other regions where thermoclines and local currents influence fish dispersal (McLean et al., 2022). These structures have been shownto provide suitable habitat for both adult and juvenile fish, potentially supporting fish communities independent of nearby natural reefs (Torquato et al., 2018). Similarly, artificial structures might influence benthopelagic coupling (Reeves et al., 2018) and nutrient transfer (Layman et al., 2013), though these dynamics remain to be evaluated in the MX-1 and similar areas. Nevertheless, it is crucial to evaluate the ichthyofauna composition from shores, tidal pools, subtidal rocky reefs, and artificial structures near the sampling area to identify habitat links and connectivity in the surrounding region. The study of oceanographic factors and larval dispersion may largely explain the fish diversity recorded in the present study, but further research is needed to understand the larger scale and dynamic of a set of oil rigs as a complex structure fish aggregation for management (Snodgrass et al., 2020).

Feeding and behavioural habits. Fish assemblages at MX-1 displayed clear depth-related patterns, likely influenced by structural complexity and resource distribution across the water column. The presence of herbivores between 5–20 m could be related to the vertical distribution limits of phototrophs such as macroalgae (Raven, Hurd, 2012). Therefore, the effect of light penetration may be reflected in the vertical distribution of herbivorous fish, which are rare in deeper layers (Torquato et al.,2018). Juvenile kyphosids, which feeds on macroalgae, appear to remain pelagic (Leis, Carson‐Ewart, 2000) dispersing by rafting (Paulay, Meyer, 2006; Casazza, Ross, 2008), crossing oceanic barriers (Pfaller et al., 2019) and arriving to reef-like habitats like oil rigs. MX-1 provided fish with greater access to planktic food sources from all levels of the water column near the shelter of the platform structure (Harvey et al.,2021). Additionally, schooling planktivores (e.g., Abudefduf, Azurina, and Chromis) were observed between 5–30 m, often displaying coordinated movement patterns (Pavlov, Kasumyan, 2000). Carnivores such as Cirrhitidae family (hawk-fishes) are usually found on the reef substrates, which offer them protection against predators and a strategic spot for hunting small fish and invertebrates (Hooker, 2009;Schmitt et al.,2009) (Fig. S8). The density of the scorpaenids was greater in the pilings, which extend until 20–40 m depth of the structure. A similar pattern was reported in the Northern Adriatic Sea, where the occurrence of scorpaenids may be related to either prey availability or a suitable habitat (Scarcella et al., 2011). We hypothesise that the pilings and crossbeams change the water flow and intensity of the currents, favouring fish to catch food (Fernández-Álamo, Färber-Lorda, 2006). Also, the high availability of food resources like plankton, invertebrates, and fish could be one of the main reasons behind the observed dominance of carnivorous fish around the MX-1 as reported in Qatari waters (Torquato et al.,2018). The hard substrate of the submerged platform provided habitat for erect flexible sessile invertebrates which increases the substrate rugosity and provides suitable space for motile invertebrates and small fish feeders such as three-banded butterfly C. humeralis (Dominici-Arosemena et al., 2005; Layman, Allgeier, 2020). The diverse swimming behaviours exhibited by fish associated with the oil platform showcase a range of adaptations and locomotive strategies within this ecosystem (Blake, 2004).

The abundance of cryptic species, such as blennioids and gobiids (Fig. S8), might be underestimated due to the limitations of the established methodology. Our main focus were pelagic and benthopelagic species, therefore we used wide-angle cameras for footage acquisition. Implementing methodologies focused on cryptic fish (Bessey et al., 2023) could allow us to reach the estimated richness and abundance of fish assemblages in oil platforms, however, it would require extending the surveying bottom-times and scientific divers dedicated on cryptic species. A potential solution to the former problem and, at the same time, for surveying deeper strata, would be implementing different decompression strategies to extend bottom times, reduce narcotic effect, and accelerate decompression. Such would be the utilisation of standard gases as a technical diving strategy. For instance, to keep an equivalent narcotic depth of ~30 m, enriched air nitrox (EANx32) could be used instead within the 0–30 m range. Alternatively, deeper ranges could be surveyed by adding helium to the mix: trimix 21/35 (30–45 m) or trimix 18/45 (45–60 m). These alternatives would require switching to EANx50 as decompression gas at 21 m during the ascent to reduce deco-times (Doolette, Mitchell, 2013; Mitchell, Doolette, 2013; Walker, 2021).

The presence of the observers can affect fish behaviour, for example, altering the swimming patterns (Scarcella et al., 2011). Fish avoid divers due to the sound of bubbles produced by open circuit SCUBA (Lindfield et al., 2014). Our presence perturbed some fish species such as the starry grouper Epinephelus labriformis (Jenyns, 1840), the large-banded blenny Ophioblennius steindachneri Jordan & Evermann, 1898,and the threadfin bass Pronotogrammus multifasciatus Gill, 1863. Additionally, some fish showed perturbed behaviour as a reaction to the video lights during the survey between 30–40 m, making it more difficult to identify them. Contrastingly, the Pacific creole-fish C. colonus was rather attracted to the bubbles emitted by the open circuit divers. Authors have shown that surveying with alternative methodologies such as using close circuit rebreathers (CCR) and remotely operated vehicles (ROV) are effective for estimating the community structure of fish, the spatial distribution of individuals, and functional diversity (Lindfield et al., 2014; Ajemian et al., 2015; de Juan et al., 2015; Torquato et al.,2018; Tothill et al., 2024). In the Gulf of Mexico, more efficient assessments of reef-associated fish communities using side-scan sonar methodology were possible. Correlating hydroacoustic images and oceanographic data can be used to answer macroscale questions otherwise more difficult with visual methods (Bollinger, Kline, 2017). Further research should consider which methodology adapts better to established research objectives, but all this depends on the aims of the study and the logistical capabilities of the surveyors. 

Decommissioning or ecosystem services. Although the installation and operation of exogenous man-made structures cause deleterious impacts on benthic communities and surroundings (Chen et al., 2024), once established, reef-like habitats such as oil rigs can increase the local fish abundance and act as fish aggregation devices (FAD) (Bull, Love, 2019). Depending on the accessibility, these fish aggregations can further be exploited by fishermen and recreational spearfishers (Fig. S9) (Polovina, 1991; Kingsford, 1999; Snodgrass et al., 2020). Nevertheless, increased fishing pressure around these structures may therefore contribute to the decrease of fish stocks in the long run if not managed properly (Jagerroos, Krause, 2016; Bull, Love, 2019; Castagnino et al., 2023). Artificial reefs provide shelter from strong currents, and food resources for consumers, conform sites for reproduction, feeding, and nursery; and supply substrate for reef-associated organisms (Jagerroos, Krause, 2016). Having identified eight commercial species (Figs. 2, 3, S9), we highlight the capacity of the habitat to host species of commercial interest, suggesting that MX-1 was contributing to fisheries stock productivity, as reported for oil rigs further north in Tumbes, and other regions of the world (Durand, Seminario, 2009; Hooker, Gonzales, 2012; Barker, Cowan, 2018; Clarke et al., 2021; Harvey et al., 2021; Mclean et al., 2022). The ecosystem services provided by MX-1 were evident, and as reported for many other oil rigs: food provision, animal genetic resources, ecological connectivity (e.g., larval dispersal), and recreational activities (MEA, 2005; Jagerroos, Krause, 2016; Villéger et al.,2017; Sommer et al.,2019; Lemasson et al., 2021; Watson et al., 2023).

During the decommissioning phase, an oil rig can be completely removed, turning the underneath seafloor back to its unobstructed prelease condition (Bull, Love, 2019). Complete removal of a platform will likely eliminate most fouling biomass, and displace associated mobile fauna, mainly fish (Pondella et al., 2015), therefore impacting on the biological resources and ecosystem services that had been formed (Jagerroos, Krause, 2016). The decommissioning order to remove the standing oil rig MX-1, included as part of the closure of Lote Z-2B, was emitted through the Directorial Resolution R.D. Nº 079-2022-MINEM/DGAAH (MINEM, 2022), and the topping strategy was applied. In March 2025, the Superior Court of Justice of Lima (Peruvian Judiciary) issued a belated appeal for protection i) recognising the role of MX-1 as an artificial reef to be considered as an area special protection, ii) rendering the decommissioning plan null and void, iii) ordering the emission of a general normative framework for the protection of artificial reefs (Corte Superior de Justicia de Lima, 2025). Although it was an important legal precedent, the ruling no longer prevented the topping action from occurring. The removal of the upper layers of MX-1 arguably disrupted the vertical zonation observed along the platform, potentially reducing the trophic connectivity throughout the water column. This alteration may have led to declines in biomass and biodiversity associated with the platform, compromised the integrity of the food web already developed, and impaired ecosystem functioning. As a result, the fish community surrounding the remaining structure may shift toward dominance by carnivorous species associated with deeper layers like P. humeralis and P. multifasciatus, potentially resulting in a simplified and less resilient ecosystem. The remnants of “Piedra Redonda”, a topped oil rig found further north in Tumbes (3°S), are found only below 50 m of sea water. Above it, very strong mid-water currents (0–20 m) occur, and no fish can be found along the first 45 m of depth (BM, pers. obs.). Although topped at shallower depths (below ~20 m of sea water), similar patterns could be expected to be found in the current situation of MX-1 such as higher current speeds and devoid of fish.

A minimum threshold for environmental, technical, societal and economic risks needs defining when making decisions regarding the decommissioning pathways and strategies (Watson et al.,2023). However, considering the aspects mentioned so far, the removal action ignored the ecological value of MX-1 and the opportunity to manage it under a “rig-to-reef” approach (i.e., converting confiscated platforms into artificial reefs, taking advantage of the ecosystem services provided by the structure which generates social and ecological compensation) (Fowler et al., 2014; Henrion et al., 2015; Bull, Love, 2019; Sommer et al., 2019; Lemasson et al., 2021). Fishing and diving around rigs are a major component of the local tourism industry. Artisanal fishermen, sport fishers, and recreational divers generally support rigs-to-reefs programs, which in turn creates hundreds of jobs (Stanley, Wilson, 1989; Frumkes, 2002; Jagerroos, Krause, 2016; van Elden et al., 2019).

The decommissioned standing oil rig MX-1 functioned as an effective fish aggregation device (FAD). The surveyed 150 m² were habitat for numerous fish aggregations, including species of commercial importance. Among the eight commercially targeted fish species identified during the survey, the Chilean jack mackerel T. murphyi was the most important pelagic species for Peruvian fisheries (Csirke, 2013). Our research confirmed a vertical zonation of fish assemblages around the decommissioned oil platform MX-1. The removal might impair the system that had been formed during its operational and abandonment phases including the fish populations that depended on the platform. Our study contributes to the understanding of the ecological role of artificial reefs in the marine environment in northern Peru (Tropical Eastern Pacific). This work also represents a valuable precedent case-study for timely implementing special protection schemes in other oil rigs yet to go through decommissioning phases. A key question persists: upon the removal of the MX-1 oil rig, where did the fish biomass relocate to? and how did the marine space change in the absence of this artificial reef?

Acknowledgments​

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This work is part of DC undergraduate thesis project registered as “Ictiofauna en la plataforma petrolera MX-1, Pacífico Tropical, Perú (4°S), durante la primavera del 2022” (N° 890-2021-PRE5), Universidad Científica del Sur (CIENTIFICA). We thank Aldo Indacochea Mejía, Dr. Junior Alberto Chuctaya Vásquez, and MSc. Adriana González Pestana for reviewing the thesis work. DC was funded by the internal research grant Beca Cabieses 2022–1 Universidad Científica del Sur (Resolución Directoral No 002-DGIDI-CIENTIFICA–2022). Thanks are due to our underwater colleagues from Spondylus and Chelonia Dive Centres, for providing diving logistics and operations. We appreciate the aid on fish identification of Eduardo M. Romero (Universidad Nacional de Piura) and Yuri Hooker (SPDA). Also, we are thankful to Alejandro Ponz for the schematic representation of MX-1 in Fig. 2. We acknowledge Donna Pringle (Dirección General de Investigación, Desarrollo e Innovación, DGIDI, CIENTIFICA) for proofreading the English version of the manuscript.

References​

---

Adams GD, Flores D. Influencia de El Niño oscilación del sur en la disponibilidad y abundancia de recursos hidrobiológicos de la pesca artesanal en Ica, Perú. Rev Biol Mar Oceanogr. 2016; 51(2):265–72.

Ajemian MJ, Wetz JJ, Shipley-Lozano B, Shively JD, Stunz GW. An analysis of artificial reef fish community structure along the northwestern Gulf of Mexico shelf: potential impacts of “rigs-to-reefs” programs. PLoS ONE. 2015; 10(5):e0126354. https://doi.org/10.1371/journal.pone.0126354

Álvarez-Noriega M, Burgess SC, Byers JE, Pringle JM, Wares JP, Marshall DJ. Global biogeography of marine dispersal potential. Nat Ecol Evol. 2020; 4(4052):1196–203. https://doi.org/10.1038/s41559-020-1238-y

Ars F, Rios R. Decommissioning: a call for a new approach. Offshore Technology Conference, Houston, Texas, USA. 2017. https://doi.org/10.4043/27717-MS

Barker VA, Cowan JH. The effect of artificial light on the community structure of reef-associated fishes at oil and gas platforms in the northern Gulf of Mexico. Environ Biol Fish. 2018; 101:153–66. https://doi.org/10.1007/s10641-017-0688-9

Bessey C, Depczynski M, Goetze JS, Moore G, Fulton CJ, Snell M et al. Cryptic biodiversity: a portfolio-approach to coral reef fish surveys. Limnol Oceanogr Methods. 2023; 21(10):594–605. https://doi.org/10.1002/lom3.10567

Blake RW. Fish functional design and swimming performance. J Fish Biol. 2004; 65(5):1193–222. https://doi.org/10.1111/j.0022-1112.2004.00568.x

Bollinger MA, Kline RJ. Validating sidescan sonar as a fish survey tool over artificial reefs. J Coast Res. 2017; 33(6):1397–407. https://doi.org/10.2112/JCOASTRES-D-16-00174.1

Boltaña S, Sanhueza N, Aguilar A, Gallardo-Escarate C, Arriagada G, Valdes JA et al. Influences of thermal environment on fish growth. Ecol Evol. 2017; 7(17):6814–25. https://doi.org/10.1002/ece3.3239

Bull AS, Love MS. Worldwide oil and gas platform decommissioning: a review of practices and reefing options. Ocean Coast Manag. 2019; 168:274–306. https://doi.org/10.1016/j.ocecoaman.2018.10.024

Buxton CD, Hartmann K, Kearney R, Gardner C. When is spillover from marine reserves likely to benefit fisheries? PLoS ONE. 2014; 9(9):e107032. https://doi.org/10.1371/journal.pone.0107032

Brochier T, Echevin V, Tam J, Chaigneau A, Goubanova K, Bertrand A. Climate change scenarios experiments predict a future reduction in small pelagic fish recruitment in the Humboldt Current system. Glob Change Biol. 2013; 19(6):1841–53. https://doi.org/10.1111/gcb.12184

Caldwell IR, Gergel SE. Thresholds in seascape connectivity: influence of mobility, habitat distribution, and current strength on fish movement. Landsc Ecol. 2013; 28:1937–48. https://doi.org/10.1007/s10980-013-9930-9

Caldwell ZR, Zgliczynski BJ, Williams GJ, Sandin SA. Reef fish survey techniques: assessing the potential for standardizing methodologies. PLoS ONE. 2016; 11(4):e0153066. https://doi.org/10.1371/journal.pone.0153066

Cappo M, Harvey E, Shortis M. Counting and measuring fish with baited video techniques—an overview. In: Australian Society for Fish Biology Workshop Proceedings. Tasmania: Australian Society for Fish Biology; 2006. p.101–14.

Casazza TL, Ross SW. Fishes associated with pelagic Sargassum and open water lacking Sargassum in the Gulf Stream off North Carolina. Fish Bull. 2008; 106:348–63. Available from: http://hdl.handle.net/1834/25466

Castagnino F, Estévez RA, Caillaux M, Velez-Zuazo X, Gelcich S. Local ecological knowledge (LEK) suggests overfishing and sequential depletion of Peruvian coastal groundfish. Mar Coast Fish. 2023; 15(6):e210272. https://doi.org/10.1002/mcf2.10272

Chaigneau A, Dominguez N, Eldin G, Vasquez L, Flores R, Grados C et al. Near-coastal circulation in the Northern Humboldt Current System from shipboard ADCP data. J Geophys Res Oceans. 2013; 118(10):5251–66. https://doi.org/10.1002/jgrc.20328

Chao A. Nonparametric estimation of the number of classes in a population. Scand J Stat. 1984; 11(4):265–70. http://www.jstor.org/stable/4615964

Chao A, Gotelli NJ, Hsieh TC, Sander EL, Ma KH, Colwell RK et al. Rarefaction and extrapolation with Hill numbers: a framework for sampling and estimation in species diversity studies. Ecol Monogr. 2014; 84(1):45–67. https://doi.org/10.1890/13-0133.1

Chavez FP, Bertrand A, Guevara-Carrasco R, Soler P, Csirke J. The northern Humboldt current system: brief history, present status and a view towards the future. Prog Oceanogr. 2008; 79(2–4):95–105. https://doi.org/10.1016/j.pocean.2008.10.012

Chen Z, Cameron TC, Couce E, Garcia C, Hicks N, Thomas GE et al. Oil and gas platforms degrade benthic invertebrate diversity and food web structure. Sci Total Environ. 2024; 929:172536. https://doi.org/10.1016/j.scitotenv.2024.172536

Chirichigno N, Vélez J. Clave para identificar los peces marinos del Perú. Inst Mar Perú Publ Esp. 1998; 503p.

Clarke KR. Non-parametric multivariate analysis of changes in community structure. Aust J Ecol. 1993; 18(1):117–43. https://doi.org/10.1111/j.1442-9993.1993.tb00438.x

Clarke TM, Reygondeau G, Wabnitz C, Robertson R, Ixquiac-Cabrera M, López M et al. Climate change impacts on living marine resources in the Eastern Tropical Pacific. Divers Distrib. 2021; 27(1):65–81. https://doi.org/10.1111/ddi.13181

Coles SL, Tarr AB. Reef fish assemblages in the western Persian Gulf: a geographically isolated population in an extreme environment. Bull Mar Sci. 1990; 47(3):696–720.

Consoli P, Romeo T, Ferraro M, Sarà G, Andaloro F. Factors affecting fish assemblages associated with gas platforms in the Mediterranean Sea. J Sea Res. 2013; 77:45–52. https://doi.org/10.1016/j.seares.2012.10.001

Coolen JWP, van der Weide B, Cuperus J, Blomberg M, van Moorsel GWNM, Faasse MA et al. Benthic biodiversity on old platforms, young wind farms, and rocky reefs. ICES J Mar Sci. 2020; 77(3):1250–65. https://doi.org/10.1093/icesjms/fsy092

Corte Superior de Justicia de Lima. Sentencia Nº 10, Exp. Nº 03693-2023-0-1801-JR-DC-03. Tercer Juzgado Especializado en lo Constitucional, Lima, Perú. 2025.

Csirke J. El Jurel Trachurus murphyi en el Perú. Rev Peru Biol. 2013; 20(1):5–08.

Cuba D, Guardia-Luzon K, Cevallos B, Ramos-Larico S, Neira E, Pons A et al. Ecosystem services provided by kelp forests of the Humboldt current system: a comprehensive review. Coasts. 2022; 2(4):259–77. https://doi.org/10.3390/coasts2040013

Cutipa-Luque LM, Alvariño L, Iannacone J. Situación actuales de las áreas marinas protegidas en el Perú y propuestas de conservación. Paideia XXI. 2020; 10(2):573–612. https://doi.org/10.31381/paideia.v10i2.3446

van Denderen D, Gislason H, van den Heuvel J, Andersen KH. Global analysis of fish growth rates shows weaker responses to temperature than metabolic predictions. Glob Ecol Biogeogr. 2020; 29(12):2203–13. https://doi.org/10.1111/geb.13189

Dominici-Arosemena A, Brugnoli-Olivera E, Cortés J, Molina-Ureña H, Quesada-Alpizar M. Community structure of eastern Pacific reef fishes (Gulf of Papagayo, Costa Rica). Tecnociencia. 2005; 7(2):19–41.

Doolette DJ, Mitchell SJ. Recreational technical diving part 2: decompression from deep technical dives. Diving Hyperb Med. 2013; 43(2):96–104.

Dugas R, Guillor Y, Fischer M. Oil rigs and offshore sport fishing in Louisiana. Fisheries. 1979; 4(6):2–10.

Durand NS, Seminario MG. Status of and trends in the use of small pelagic fish species for reduction fisheries and for human consumption in Peru. Fish as Feed Inputs for Aquac. 2009; 325.

van Elden S, Meeuwig JJ, Hobbs RJ, Hemmi JM. Offshore oil and gas platforms as novel ecosystems: a global perspective. Front Mar Sci. 2019; 6:548. https://doi.org/10.3389/fmars.2019.00548

van Elden S, Tothill T, Meeuwig JJ. Fish associated with subsea pipelines and their rock berms. APPEA J. 2022; 62(2):362–67. https://doi.org/10.1071/AJ21181

Escribano R, Baneri G, Farías L, Gallardo VA, González HE, Gutiérrez D et al. Biological and chemical consequences of the 1997–1998 El Niño in the Chilean coastal upwelling system: a synthesis. Deep Sea Res Part II Topical Stud Oceanogr. 2004; 51(20):2389–411. https://doi.org/10.1016/j.dsr2.2004.08.011

Fernández-Álamo MA, Färber-Lorda J. Zooplankton and the oceanography of the eastern tropical Pacific: a review. Prog Oceanogr. 2006; 69(2–4):318–59. https://doi.org/10.1016/j.pocean.2006.03.003

Fowler AM, Macreadie PI, Jones DOB, Booth DJ. A multi-criteria decision approach to decommissioning of offshore oil and gas infrastructure. Ocean Coast Manag. 2014; 87:20–29. https://doi.org/10.1016/j.ocecoaman.2013.10.019

Fu F. Design of offshore structures. In: Fu F, editor. Design and analysis of tall and complex structures. Oxford: Butterworth-Heinemann; 2018. p.251–93. https://doi.org/10.1016/b978-0-08-101018-1.00008-3

Fricke R, Eschmeyer WN, Van der Laan R. Eschmeyer’s catalog of fishes: genera, species, references [Internet]. San Francisco: California Academy of Science; 2018. Available from: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp

Friedlander AM, Ballesteros E, Fay M, Sala E. Marine communities on oil platforms in Gabon, West Africa: high biodiversity oases in a low biodiversity environment. PLoS ONE. 2014; 9(8):e103709. https://doi.org/10.1371/journal.pone.0103709

Froese R, Pauly D, editors. FishBase. World Wide Web electronic publication. 2023; Available from: www.fishbase.org

Frumkes DR. The status of the California Rigs-to-Reefs Programme and the need to limit consumptive fishing activities. ICES J Mar Sci. 2002; 59:272–76. https://doi.org/10.1006/jmsc.2002.1289

Green AL, Maypa AP, Almany GR, Rhodes KL, Weeks R, Abesamis RA et al. Larval dispersal and movement patterns of coral reef fishes, and implications for marine reserve network design. Biol Rev. 2015; 90(4):1215–47. https://doi.org/10.1111/brv.12155

Guevara JT, Milla DV. Successful experiences of sustainable land use in hyperarid, arid and semiarid zones from Peru. In: Sivakumar MVK, Ndiang’ui N, editors. Climate and Land Degradation. Environmental Science and Engineering. Berlin, Heidelberg: Springer; 2007. p.501–21. https://doi.org/10.1007/978-3-540-72438-4_28

Gutiérrez D, Akester M, Naranjo L. Productivity and sustainable management of the Humboldt Current large marine ecosystem under climate change. Environ Dev. 2016; 17:126–44. https://doi.org/10.1016/j.envdev.2015.11.004

Hammer Ø, Harper DAT, Ryan PD. PAST: Palentological statistics software package for education and data analysis. Paleontol Electron. 2001; 4:1–09. Available from: https://palaeo-electronica.org/2001_1/past/past.pdf

Harvey ES, Watts SL, Saunders BJ, Driessen D, Fullwood LAF, Bunce M et al. Fish assemblages associated with oil and gas platforms in the Gulf of Thailand. Front Mar Sci. 2021; 8. https://doi.org/10.3389/fmars.2021.664014

Helvey M. Are southern California oil and gas platforms essential fish habitat? ICES J Mar Sci. 2002; 59:266–71. https://doi.org/10.1006/jmsc.2002.1226

Henrion M, Bernstein B, Swamy S. A multi-attribute decision analysis for decommissioning offshore oil and gas platforms. Integr Environ Assess Manag. 2015;11:594–609. https://doi.org/10.1002/ieam.1693

Hooker Y. Nuevos registros de peces costeros tropicales para el Perú. Rev Peru Biol. 2009; 16(1):33–41.

Hooker Y, Barrangan Y, Gamero D, More A. Inventario preliminar de la fauna subacuática de isla Foca, Piura [Internet]. Informe Científico. NCI-Perú/PUCH; 2012.

Hooker Y, Gonzales A. Las plataformas petroleras del norte peruano como centros debiodiversidad y conservación de especies amenazadas. In: Blanco J, editor. Plataformas petroleras marinas como arrecifes artificiales y su implicancia en la pesca artesanal en la zona de Tumbes. Fundación Zuñiga y Ribero; 2012.

Hooker Y, Prieto-Rios E, Solís-Marín FA. Echinoderms of Peru. In: Alvarado J, Solis-Marin F, ediotrs. Echinoderm research and diversity in Latin America. Berlin, Heidelberg: Springer; 2013. p.277–99. Available from: https://doi.org/10.1007/978-3-642-20051-9_8

Hooker Y, More A, Ubillus O. Propuesta de creación de la Reserva Nacional Isla Foca. Reportes técnicos. 2011. Available from: https://www.researchgate.net/publication/299584285_PROPUESTA_DE_CREACION_DE_LA_RESERVA_NACIONAL_ISLA_FOCA

Hooker Y, Ubillus O. Propuesta de creación de la Reserva Nacional El Ñuro y Arrecifes de Punta Sal. Unidad Marino Costera, Servicio Nacional de Áreas Naturales Protegidas por el Estado (SERNANP–MINAN); 2011.

Humman P, DeLoach N. Reef fish identification: Galapagos. 2a ed. Jacksonville, Florida: New World Publications; 2003.

Ibanez-Erquiaga B, Pacheco AS, Rivadeneira MM, Tejada CL. Biogeographical zonation of rocky intertidal communities along the coast of Peru (3.5–13.5 S Southeast Pacific). PLoS ONE. 2018; 13(11):e0208244. https://doi.org/10.1371/journal.pone.0208244

Jablonski S. The interaction of the oil and gas offshore industry with fisheries in Brazil: the “Stena Tay” experience. Braz J Oceanogr. 2008; 56(4):289–96.

Jagerroos S, Krause P. Rigs-to-reef: Impact or enhancement on marine biodiversity. J Ecosyst Ecogr. 2016; 6(2):187. https://doi.org/10.4172/2157-7625.1000187

Jacinto ME, Chávez JH, Martínez CG, Guzmán MR. Evaluación de la calidad del medio marino en la Bahía de Talara. IMARPE. 1996; 41:19–35. Available from: https://repositorio.imarpe.gob.pe/bitstream/20.500.12958/1223/1/IP%2041.2.pdf

de Juan S, Hewitt J, Thrush S, Freeman D. Standardizing the assessment of functional integrity in benthic ecosystems. J Sea Res. 2015; 98:33–41. https://doi.org/10.1016/j.seares.2014.06.001

Kingsford MJ. Fish attraction devices (FADs) and experimental designs. Sci Mar. 1999; 63(3–4):181–90. https://doi.org/10.3989/scimar.1999.63n3-4181

Layman CA, Allgeier JE, Yeager LA, Stoner EW. Thresholds of ecosystem response to nutrient enrichment from fish aggregations. Ecology. 2013; 94(2):530–36. https://doi.org/10.1890/12-0705.1

Layman CA, Allgeier JE. An ecosystem ecology perspective on artificial reef production. J Appl Ecol. 2020; 57(11):2139–48. https://doi.org/10.1111/1365-2664.13748

Leis JM, Carson-Ewart BM. Behaviour of pelagic larvae of four coral-reef fish species in the ocean and an atoll lagoon. Coral Reefs. 2000; 19(3):247–57. https://doi.org/10.1007/s003380000115

Lemasson AJ, Knights AM, Thompson M, Lessin G, Beaumont N, Pascoe C et al. Evidence for the effects of decommissioning man-made structures on marine ecosystems globally: a systematic map protocol. Environ Evid. 2021; 10(1):4. https://doi.org/10.1186/s13750-021-00218-y

Li X, Hu ZZ, Tseng YH, Liu Y, Liang P. A historical perspective of the La Niña event in 2020/2021. J Geophys Res Atmos. 2022; 127(7):e2021JD035546. https://doi.org/10.1029/2021JD035546

Lindfield SJ, Harvey ES, McIlwain JL, Halford AR. Silent fish surveys: bubble-free diving highlights inaccuracies associated with SCUBA-based surveys in heavily fished areas. Methods Ecol Evol. 2014; 5(10):1061–69. https://doi.org/10.1111/2041-210X.12262

Love MS, Kui L, Claisse JT. The role of jacket complexity in structuring fish assemblages in the midwaters of two California oil and gas platforms. Bull Mar Sci. 2019; 95(4):597–615. https://doi.org/10.5343/bms.2017.1131

Love MS, Schroeder DM, Lenarz W, MacCall A, Bull AS, Thorsteinson L. Potential use of offshore marine structures in rebuilding an overfished rockfish species, bocaccio (Sebastes paucispinis). Fish Bull. 2006; 104(3):383–90.

Margalef R. Temporal succession and spatial heterogeneity in phytoplankton. In: Buzzati-Traverso AA, editor. Perspectives in Marine Biology. Oakland: University California Press; 1958. p.323–50.

Martin CJ, Lowe CG. Assemblage structure of fish at offshore petroleum platforms on the San Pedro Shelf of southern California. Mar Coast Fish. 2010; 2(1):180–94. https://doi.org/10.1577/C09-037.1

McLean D, Bond T, Harvey ES, Ierodiaconou D, Cure K, Taylor M et al. Importance of Australia’s offshore oil and gas infrastructure for fish. APPEA J. 2021; 61(2):429–37. https://doi.org/10.1071/AJ20106

McLean DL, Ferreira LC, Benthuysen JA, Miller KJ, Schläppy ML, Ajemian MJ et al. Influence of offshore oil and gas structures on seascape ecological connectivity. Glob Chang Biol. 2022; 28(11):3515–36. https://doi.org/10.1111/gcb.16134

McLean DL, Taylor MD, Giraldo Ospina A, Partridge JC. An assessment of fish and marine growth associated with an oil and gas platform jacket using an augmented remotely operated vehicle. Cont Shelf Res. 2019; 179:66–84. https://doi.org/10.1016/j.csr.2019.04.006

Meyer-Gutbrod EL, Kui L, Nishimoto MM, Love MS, Schroeder DM, Miller RJ. Fish densities associated with structural elements of oil and gas platforms in southern California. Bull Mar Sci. 2019; 95(4):639–56. https://doi.org/10.5343/bms.2018.0078

Millennium Ecosystem Assessment (MEA). Ecosystems and human well-being: wetlands and water [Internet]. World Resources Institute: Washington, DC, USA; 2005. Available from: https://www.millenniumassessment.org/documents/document.358.aspx.pdf

Miloslavich P, Klein E, Díaz JM, Hernandez CE, Bigatti G, Campos L et al. Marine biodiversity in the Atlantic and Pacific coasts of South America: knowledge and gaps. PLoS ONE. 2011; 6(1):14631. https://doi.org/10.1371/journal.pone.0014631

Ministerio de Medio Ambiente (MINAM). Resolución Ministerial Nº 295-2023 [Internet]. El Peruano. Lima; 2023. Available from: https://www.gob.pe/institucion/minam/normas-legales/5606569-295-2023-minam

Ministerio de Medio Ambiente (MINAM). Decreto SupremoN° 003-2024-MINAM [Internet]. El Peruano. Lima; 2024a. Available from: https://cdn.www.gob.pe/uploads/document/file/6252070/5502735-ds-003-2024-minam.pdf

Ministerio de Medio Ambiente (MINAM). Instituto Geofísico del Perú. Subdirección de Ciencias de la Atmósfera e Hidrósfera. Eventos El Niño y La Niña Costeros [Internet]. Lima; 2024b. Available from: http://met.igp.gob.pe/elnino/

Ministerio de Cultura (MINCUL). Resolución Vice Ministerial N^o 117-2018 [Internet]. El Peruano. Lima; 2018. Available from: https://www.gob.pe/institucion/cultura/normas-legales/203903-117-2018-vmpcic-mc

Ministerio de Energía y Minas (MINEM). Resolución Directoral R.D. Nº 079-2022-MINEM/DGAAH [Internet]. El Peruano. Lima; 2022. Available from: https://www.gob.pe/institucion/minem/normas-legales/2922252-079-2022-minem-dgaah

Mitchell SJ, Doolette DJ. Recreational technical diving part 1: an introduction to technical diving methods and activities. Diving Hyperb Med. 2013; 43(2):86–93.

Moreno B. Keeping track of scientific dives in countries with incipient diving programmes: the SciDive record forms. Pol Hyperb Res. 2020; 72(3):29–38. https://doi.org/10.2478/phr-2020-0015

O’Gorman EJ, Ólafsson OP, Demars BOL, Friberg N, Guðbergsson G, Hannesdóttir ER et al. Temperature effects on fish production across a natural thermal gradient. Glob Chang Biol. 2016; 22(9):3206–20. https://doi.org/10.1111/gcb.13233

Pacheco AS, Moran-Valverde J, Aguilar S, Vildoso B, Vélez-Zuazo X. Fish assemblages at the surroundings of a port terminal of liquefied natural gas in the central coast of Peru. Environ Biol Fish. 2023; 106:1443–54. https://doi.org/10.1007/s10641-023-01430-0

Paulay G, Meyer C. Dispersal and divergence across the greatest ocean region: do larvae matter? Integr Comp Biol. 2006; 46:269–81. https://doi.org/10.1093/icb/icj027

Pavlov DS, Kasumyan AO. Patterns and mechanisms of schooling behaviour in fish: a review. J Ichthyol. 2000; 40(2):163–231.

Petro-Tech Peruana SA. Plataforma MX-1 (Máncora) (Plano E-2989). Ingenieria Facilidades y Estructuras. 2009.

Pfaller JB, Payton AC, Bjorndal KA, Bolten AB, McDaniel SF. Hitchhiking the high seas: global genomics of rafting crabs. Ecol Evol. 2019; 9(3):957–74. https://doi.org/10.1002/ece3.4694

Pielou EC. The usefulness of ecological models: a stock-taking. Q Rev Biol. 1981; 56(1):17–31. http://www.jstor.org/stable/2826368

Polovina JJ. A global perspective on artificial reefs and fish aggregating devices. RAPA Rep. 1991; 11:251–59.

Pondella DJ, Zahn LA, Love MS, Siegel D, Bernstein BB. Modeling fish production for southern California’s petroleum platforms. Integr Environ Assess Manag. 2015; 11(4):584–93. https://doi.org/10.1002/ieam.1689

Pulsipher AG, Daniel WB. Onshore disposition of offshore oil and gas platforms: western politics and international standards. Ocean Coast Manag. 2000; 43(12):973–95. https://doi.org/10.1016/S0964-5691(00)00073-9

Pyle RL. Advanced technical diving. In: Loya Y, Puglise K, Bridge T, editors. Mesophotic Coral Ecosystems. Coral reefs of the World, vol 12. Springer, Cham; 2019. p.959–72. https://doi.org/10.1007/978-3-319-92735-0_50

Rassweiler A, Dubel AK, Hernan G, Kushner DJ, Caselle JE, Sprague JL et al. Roving divers surveying fish in fixed areas capture similar patterns in biogeography but different estimates of density when compared with belt transects. Front Mar Sci. 2020; 7:272. https://doi.org/10.3389/fmars.2020.00272

Raven JA, Hurd CL. Ecophysiology of photosynthesis in macroalgae. Photosynth Res. 2012; 113:105–25. https://doi.org/10.1007/s11120-012-9768-z

Reeves DB, Chesney EJ, Munnelly RT, Baltz DM, Marx BD. Abundance and distribution of reef-associated fishes around small oil and gas platforms in the northern Gulf of Mexico’s hypoxic zone. Estuar Coasts. 2018; 41:1835–47. https://doi.org/10.1007/s12237-017-0349-4

Rilov G, Benayahu Y. Fish assemblage on natural versus vertical artificial reefs: the rehabilitation perspective. Mar Biol. 2000; 136:931–42. https://doi.org/10.1007/s002279900250

Robertson DR, Allen G. Shorefishes of the Tropical Eastern Pacific online information system. Version 2.0. Smithsonian Tropical Research Institute, Balboa, Panama. 2015.

Scarcella G, Grati F, Fabi G. Temporal and spatial variation of the fish assemblage around a gas platform in the Northern Adriatic Sea, Italy. Turk J Fish Aquat Sci. 2011; 11(3)3.

Schmitt R J, Holbrook SJ, Brooks AJ, Lape JC Intraguild predation in a structured habitat: distinguishing multiple-predator effects from competitor effects. Ecology. 2009; 90(9):433–44. http://doi.org/10.4194/1303-2712-v11_3_14

Seaman Jr. W, Lindberg WJ, Gilbert CR, Frazer TK. Fish habitat provided by obsolete petroleum platforms off southern Florida. Bull Mar Sci. 1989; 44(2):1014–22.

Shani A, Polak O, Shashar N. Artificial reefs and mass marine ecotourism. Tour Geogr. 2012; 14(3):361–82. https://doi.org/10.1080/14616688.2011.610350

Shannon CE, Weaver W. The mathematical theory of communication. Champaign: University of Illinois Press; 1994.

Siccha-Ramirez R, Luque C, Vera M, Britzke R, Guevara M, Castillo D et al. Catálogo ilustrado de la ictiofauna de la región Tumbes. Callao: Instituto del Mar del Perú, Publicación Especial; 2022.

Sih TL, Cure K, Yilmaz IN, McLean D, Macreadie PI. Marine life and fisheries around offshore oil and gas structures in southeastern Australia and possible consequences for decommissioning. Front Mar Sci. 2022; 9:979212. https://doi.org/10.3389/fmars.2022.979212

Snodgrass DJ, Orbesen ES, Walter JF, Hoolihan JP, Brown CA. Potential impacts of oil production platforms and their function as fish aggregating devices on the biology of highly migratory fish species. Rev Fish Biol Fish. 2020; 30:405–22. https://doi.org/10.1007/s11160-020-09605-z

Sommer B, Fowler AM, Macreadie PI, Palandro DA, Aziz AC, Booth DJ. Decommissioning of offshore oil and gas structures – Environmental opportunities and challenges. Sci Total Environ. 2019; 658:973–81. https://doi.org/10.1016/j.scitotenv.2018.12.193

Sorensen T. A method of establishing groups of equal amplitude in plant sociology based on similarity of species content and its application to analyses of the vegetation on Danish commons. Biol Skr. 1948; 5:1–34.

Spalding MD, Fox HE, Allen GR, Davidson N, Ferdaña ZA, Finlayson M et al. Marine ecoregions of the World: a bioregionalization of coastal and shelf areas. BioScience. 2007; 57(7):573–83. https://doi.org/10.1641/B570707

Stanley DR, Wilson CA. Utilization of offshore platforms by recreational fishermen and scuba divers off the Louisiana coast. Bull Mar Sci. 1989; 44(2):767–75.

Tarazona J, Gutiérrez D, Paredes C, Indacochea A. Overview and challenges of marine biodiversity research in Peru. Gayana. 2003; 67(2):206–31. https://doi.org/10.4067/S0717-65382003000200009

Thurstan R, Flower J, Beger M, Dudgeon C, Gomez K, Ortiz J et al. Survey methods manual unidive point lookout ecological assessment (PLEA). Brisbane: the University of Queensland Underwater Club; 2014.

Todd VLG, Lavallin EW, Macreadie PI. Quantitative analysis of fish and invertebrate assemblage dynamics in association with a North Sea oil and gas installation complex. Mar Environ Res. 2018; 142:69–79. https://doi.org/10.1016/j.marenvres.2018.09.018

Todd VLG, Susini I, Williamson LD, Todd IB, McLean DL, Macreadie PI. Characterizing the second wave of fish and invertebrate colonization of an offshore petroleum platform. J Mar Sci. 2021; 78(3):1131–45. https://doi.org/10.1093/icesjms/fsaa245

Torquato R, Torquato F, Jensen H, Range P, Bach S, Sigsgaard E et al. Vertical zonation and functional diversity of fish assemblages revealed by ROV videos at oil platforms in The Gulf. J Fish Biol. 2018; 91(3):947–67. https://doi.org/10.1111/jfb.13394

Tothill T, Meeuwig JJ, van Elden S. The vertical distribution of fish on two offshore oil platforms. Front Mar Sci. 2024; 11:1328672. https://doi.org/10.3389/fmars.2024.1328672

Vermeij GJ, DeVries TJ, Griffin M, Nielsen SN, Ochoa D, Rivadeneira MM et al. The temperate marine Peruvian Province: how history accounts for its unusual biota. Ecol Evol. 2024; 14(7):e70048. https://doi.org/10.1002/ece3.70048

Victor BC, Wellington GM. Endemism and the pelagic larval duration of reef fishes in the eastern Pacific Ocean. Mar Ecol Prog Ser. 2000; 205:241–48. Available from: https://www.int-res.com/articles/meps/205/m205p241.pdf

Villéger S, Brosse S, Mouchet M, Mouillot D, Vanni MJ. Functional ecology of fish: current approaches and future challenges. Aquatic Sci. 2017; 79(4):783–801. https://doi.org/10.1007/s00027-017-0546-z

Walker R. Standard gases: the simplicity of everyone singing the same song [Internet]. InDepth Mag; 2021. Available from: https://indepthmag.com/standard-gases-the-advantages-of-having-everyone-singing-the-same-song/

Watson SM, McLean DL, Balcom BJ, Birchenough SN, Brand AM, Camprasse EC et al. Offshore decommissioning horizon scan: research priorities to support decision-making activities for oil and gas infrastructure. Sci Total Environ. 2023; 878:163015. https://doi.org/10.1016/j.scitotenv.2023.163015

Whittaker RH. Vegetation of the Siskiyou mountains, Oregon and California. Ecol Monogr. 1960; 30(3):279–338.

World Ocean Review 3. Marine resources, opportunities and risks [Internet]. Hamburg, Germany: Maribus gGmbH in cooperation with Future Earth, Kiel Marine Sciences; 2014. Available from: https://worldoceanreview.com/en/wor-3/

Zavala E, Britzke R, Siccha-Ramírez Z, Ramirez JL. DNA barcoding of marine rocky reef fishes from northern Peru suggests a parapatric speciation in the Tropical Eastern Pacific. Ecol Evol. 2025; 15(3):e70125. https://doi.org/10.1002/ece3.70125

Zuta S, Guillén O. Oceanografía de las aguas costeras del Perú. Bol Inst Mar Perú. 1970; 2(5):157–324. Available from: https://hdl.handle.net/20.500.12958/949

Authors

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Diego Cuba^1,2 and Bernabé Moreno^1,2,3,4

^[1]    Carrera de Biología Marina, Universidad Científica del Sur, Panamericana Sur km 19, Lima 15067, Peru. (DC) diegobiomarina@gmail.com

^[2]    Coastal Ecosystems of Peru Research Group (COEPeru), Universidad Científica del Sur, Panamericana Sur km 19, Lima 15067, Peru. (BM) bmorenole@cientifica.edu.pe (corresponding author).

^[3]    Marine Ecology Department, Institute of Oceanology Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland

^[4]    Grupo de Investigación Comunidades Acuáticas, Universidad Científica del Sur, Panamericana Sur km 19, Lima 15067, Peru.

Authors’ Contribution

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Diego Cuba: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing-original draft, Writing-review and editing.

Bernabé Moreno: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing-original draft, Writing-review and editing.

Ethical Statement​

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This study was conducted in accordance with ethical guidelines, following approval by the institutional Ethics Committee (approval No. 040-CIEI-AB-CIENTÍFICA-2022).

Competing Interests

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The author declares no competing interests.

How to cite this article

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Cuba D, Moreno B. Ichthyofauna associated with a no longer standing decommissioned oil plataform in the Tropical Eastern Pacific (4°S, Peru). Neotrop Ichthyol. 2025; 23(2):e240122. https://doi.org/10.1590/1982-0224-2024-0122

Copyright​

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This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Distributed under

Creative Commons CC-BY 4.0

© 2025 The Authors.

Diversity and Distributions Published by SBI

Accepted June 6, 2025

Submitted November 14, 2024

Epub August 04, 2025