Mario Espinoza

University of Costa Rica | UCR · Escuela de Biología

No-take marine protected areas (MPAs) can mitigate the effects of overfishing, climate change and habitat degradation, which are leading causes of an unprecedented global biodiversity crisis. However, assessing the effectiveness of MPAs, especially in remote oceanic islands, can be logistically challenging and often restricted to relatively shallow...

Bahía Santa Elena is a tropical bay located in the northern Pacific region of Costa Rica. This region experiences a period of reduced precipitation from July to August, known as mid-summer drought, induced by the intensification of northeastern winds from the Caribbean Low-Level Jet. Intensification of upwelling-favorable winds can cool surface wat...

In November 2021, the IUCN Species Survival Commission Shark Specialist Group held a series of online workshops to reassess the Red List status of the five sawfish species (family Pristidae). This process concluded in December 2023 with the publication of the final assessment, for the narrow sawfish Anoxypristis cuspidata. Since the previous asses...

Long-distance movements associated with environmental and ecological drivers are common in a wide array of mobile marine species. Understanding such movements and associated drivers is particularly important for management and conservation of threatened species, which may be exposed to anthropogenic threats throughout their range. Pacific nurse sha...

A global survey of coral reefs reveals that overfishing is driving resident shark species toward extinction, causing diversity deficits in reef elasmobranch (shark and ray) assemblages. Our species level analysis revealed global declines of 60 to 73% for five common resident reef shark species and that individual shark species were not detected at...

Abstract The Bull Shark (Carcharhinus leucas) faces varying levels of exploitation around the world due to its coastal distribution. Information regarding population connectivity is crucial to evaluate its conservation status and local fishing impacts. In this study, we sampled 922 putative Bull Sharks from 19 locations in the first global assessme...

Sharks and rays are key functional components of coral reef ecosystems, yet many populations of a few species exhibit signs of depletion and local extinctions. The question is whether these declines forewarn of a global extinction crisis. We use IUCN Red List to quantify the status, trajectory, and threats to all coral reef sharks and rays worldwid...

Defining demographically independent units and understanding patterns of gene flow between them is essential for managing and conserving exploited populations. The critically endangered scalloped hammerhead shark, Sphyrna lewini , is a coastal semi-oceanic species found worldwide in tropical and subtropical waters. Pregnant females give birth in sh...

Unifying models have shown that the amount of space used by animals (e.g., activity space, home range) scales allometrically with body mass for terrestrial taxa; however, such relationships are far less clear for marine species. We compiled movement data from 1,596 individuals across 79 taxa collected using a continental passive acoustic telemetry...

Understanding the population structure of a species is important to accurately assess its conservation status and manage the risk of local extinction. The Bull Shark ( Carcharhinus leucas ) faces varying levels of exploitation around the world due to its coastal distribution. Information regarding population connectivity is crucial to evaluate its...

Article Resumen.-Después de su deposición, las cápsulas de condrictios se exponen con frecuencia a numerosas amenazas que afectan su supervivencia. Sin embargo, los factores ecológicos que afectan el desarrollo y la supervivencia de los embriones dentro de las cápsulas siguen sin estar claros. El objetivo de este estudio fue cuantificar y describir...

After deposition, chondrichthyan egg capsules are frequently exposed to numerous threats that affect their survival. However, the ecological factors affecting the development and survival of embryos inside egg capsules remain unclear. The aims of this study was to quantify and describe two ecological factors that affect of the Shorttail fanskate Sy...

Introducción: El Pacífico Norte de Costa Rica es una región diversa y productiva; sin embargo, tenemos un escaso conocimiento sobre el estado de los recursos marinos y la dinámica pesquera, particularmente de la pesca artesanal en el Golfo de Santa Elena, uno de los principales caladeros de la zona. Objetivo: Caracterizar la dinámica de esta pesque...

High-frequency (>175 kHz) acoustic telemetry transmitters are increasingly being used to track the movements of small fishes and other aquatic organisms. These transmitters, which are often smaller than conventional types, have primarily been used in freshwater, yet limited information is available on their efficacy in estuarine or marine environme...

Reef fish assemblages under fishing pressure generally exhibit a lower fish biomass, abundance, and size structure, which can be counteracted with the creation of marine protected areas (MPAs). The effectiveness of MPAs relies on enforcement and compliance, which is particularly challenging in developing countries with financial and socioeconomic l...

Introducción: La naturaleza tropical está experimentando una amenaza sin precedentes que incluye comunidades de peces costeros que requieren un constante seguimiento de la presencia de especies. El uso simultáneo de varios métodos de monitoreo debería reducir el sesgo causado por la selectividad de cada método. Objetivo: Este estudio uso cuatro di...

Latin American countries have a high diversity of sharks, rays, and chimaeras, yet many species are at high risk of extinction due to numerous threats. The conservation of chondrichthyans is key to achieving healthy and productive aquatic ecosystems, and countries in Latin America are increasingly recognizing the need for aligning conservation stra...

Defining demographically independent units and understanding gene flow between them is essential for managing and conserving exploited populations. The scalloped hammerhead shark, Sphyrna lewini , is a coastal semi-oceanic species found worldwide in tropical and subtropical waters. Pregnant females give birth in shallow coastal estuarine habitats t...

Understanding the link between seamounts and large pelagic species (LPS) may provide important insights for the conservation of these species in open water ecosystems. The seamounts along the Cocos Ridge in the Eastern Tropical Pacific (ETP) ocean are thought to be ecologically important aggregation sites for LPS when moving between Cocos Island (C...

Tiger sharks (Galeocerdo cuvier) play an important ecological role as top predators, yet knowledge of their reproductive ecology is scarce. Here, the authors report the first observation of a potential neonate G. cuvier at Cocos Island, a predator‐dominated oceanic island in the Eastern Tropical Pacific (ETP). The individual was detected using bait...

Few studies have considered linkages of mobile predators across large spatial scales despite their significant and often critical role in maintaining ecosystem function and health. The bull shark (Carcharhinus leucas) is a large, widespread coastal predator capable of undertaking long-range movement, but there is still limited understanding of intr...

Delineation of population structure (i.e. stocks) is crucial to successfully manage exploited species and to address conservation concerns for threatened species. Fish migration and associated movements are key mechanisms through which discrete populations mix and are thus important determinants of population structure. Detailed information on fish...

The southern banded guitarfish, Zapteryx xyster, and the Velez ray, Raja velezi, are two endemic elasmobranchs in the eastern Tropical Pacific that are commonly caught by the bottom-trawl fishery. Reproductive cycles of these batoids were inferred from the hepatosomatic and gonadosomatic indexes (males and females) and the oviductal gland width and...

Fishes play numerous key ecological roles that are critical for maintaining the structure and function of coral reefs. Natural and anthropogenic disturbances can produce structural changes in coral reef habitats, which consequently may affect the trophic structure and dynamics of reef fish assemblages. Therefore, changes in the coral cover of coral...

Due to the ongoing and increasing demand for their products, chondrichthyan populations are often subject to intense exploitation by many small-scale and industrial fisheries worldwide. This situation generates an urgent need for conservation and management of many chondrichthyan species. This includes the Eastern Pacific round rays of the family U...

Reef fish assemblages are exposed to a wide range of anthropogenic threats as well as chronic natural disturbances. In upwelling regions, for example, there is a seasonal influx of cool nutrient‐rich waters that may shape the structure and composition of reef fish assemblages. Given that climate change may disrupt the natural oceanographic processe...

Understanding the link between seamounts and large pelagic species (LPS) is critical for guiding management and conservation efforts in open water ecosystems. The seamounts along the Cocos Ridge in the Eastern Tropical Pacific (ETP) are thought to play a critical role for LPS moving between Cocos Island (Costa Rica) and Galapagos Islands (Ecuador)....

Hypanus dipterurs red list assessment

Understanding how threatened species are distributed in space and time can have direct applications to conservation planning. However, implementing standardized methods to monitor populations of wide‑ranging species is often expensive and challenging. In this study, we used baited remote underwater video stations (BRUVS) to quantify elasmobranch ab...

Animal movement has direct applications in spatial management and conservation planning, yet it is rarely taken into account for the design of natural protected areas. For instance, reef shark species are thought to benefit from marine protected area networks, even though their movement behaviour remains poorly characterized. Poor understanding of...

Action plan for the hawksbill turtle Eretmochelys imbricata in the Pacific coast of Costa Rica

Anthropogenic noise associated with shipping has emerged as a major disruptor of aquatic animal behavior worldwide. The Arctic marine realm has historically experienced little noise‐generating human activity; however, the continual loss of sea ice has facilitated a dramatic increase in shipping activity. Here, we use a combination of acoustic telem...

The Critically Endangered largetooth sawfish Pristis pristis is one of the most threatened elasmobranch species and is currently thought to be locally extinct in at least 27 countries. Although largetooth sawfish information in Central America is scarce, recent records show that this species is still present in Costa Rica, yet its distribution and...

Biomarkers are frequently used in ecotoxicology as they allow to study toxicant effects happening at low concentrations of exposure. However, most sublethal studies only evaluate cellular biomarkers which lack evident ecological relevance. We used a multibiomarker approach to estimate the toxic effects of ethoprophos, an organophosphate insecticide...

Defining the role of reef predators is particularly important given the rapid rate at which some species are declining, yet knowledge of trophic relationships is often lacking, particularly for large wide-ranging species that may use coral reefs seasonally or opportunistically. We used a multi-tissue stable isotope approach to investigate the troph...

Benthic structure of coral reefs determines the availability of refuges and food sources. Therefore, structural changes caused by natural and anthropogenic disturbances can have negative impacts on reef‐associated communities. During the 1990s, coral reefs from Bahía Culebra were considered among the most diverse ecosystems along the Pacific coast...

The occurrence of sharks on coral reefs has been well documented for decades, especially since the advent of SCUBA diving. Despite this, it is only within the last decade that substantial research effort has been directed at these species. Research effort has increased in conjunction with the realization that reef shark populations have experienced...

Los juegos ecológicos y la recreación ambiental como estrategias para la conservación del pez sierra

Sea ice reduction in the Arctic is allowing for increased vessel traffic and activity. Vessel noise is a known anthropogenic disturbance, but its effects on Arctic fish are largely unknown. Using acoustic telemetry — Vemco positioning system — we quantified the home ranges and fine-scale movement types (MT) of shorthorn sculpin (Myoxocephalus scorp...

Understanding key aspects of the biology and ecology of chondrichthyan fishes (sharks, rays, and chimeras), as well as the range of threats affecting their populations is crucial given the rapid rate at which some species are declining. In the Eastern Tropical Pacific (ETP), the lack of knowledge, unreliable (or non-existent) landing statistics, an...

There are 99 chondrichthyan species formally recorded in the literature and/or with voucher specimens collected within Costa Rican waters. These species are grouped in 2 subclasses (Holocephali and Elasmobranchii), 12 orders, 34 families, and 50 genera. This checklist includes data for a total of 87 and 24 species formally recorded in Costa Rican P...

The impact of shrimp trawl fisheries on slow-growing demersal sharks, skates and rays has been widely documented. Yet, a lack of catch records and biological information has hindered improvements in elasmobranch bycatch management, particularly in tropical regions. When information is scarce, data-poor methods can be valuable tools to guide the man...

The overexploitation of sharks by illicit finning industries negatively impacts the overall functioning of the marine ecosystem. Due to the finning process, differentiating shark species pose major difficulties. This study genetically identifies hammerhead sharks and attempts to detect a connection between dorsal fin morphometry with the overall to...

The deep-water shrimp fishery is of great commercial importance along the Pacific coast of Latin America. In Costa Rica, shrimp resources have declined considerably over the last decade. Therefore, fisheries have shifted towards teleost species such as the Pacific bearded brotula Brotula clarkae. Little is known about the biology and life history o...

Sharks are thought to play an important role in structuring coral reef communities, but their role may be masked by the high level of functional redundancy. For example, coral reefs have a high diversity of predatory fishes that could be sharing similar ecological roles. Therefore, a better understanding the feeding ecology and trophic interactions...

The deep-water shrimp fishery is of great commercial importance along the Pacific coast of Latin America. In Costa Rica, shrimp resources have declined considerably over the last decade. Therefore, fisheries have shifted towards teleost species such as the Pacific bearded brotula Brotula clarkae. Little is known about the biology and life history o...

Understanding animal movement decisions that involve migration is critical for evaluating population connectivity, and thus persistence. Recent work on sharks has shown that often only a portion of the adult population will undertake migrations, while the rest may be resident in an area for long periods. Defining the extent to which adult sharks us...

The present study analyzed the diet composition, ontogenetic shifts and dietary overlap of Brotula clarkae in relation to stage of maturity and sex. Samples were collected from the trawling fishery along the Pacific coast of Costa Rica (2011– 2012) at depths ranging from 41.4 to 168.3 m; however, over 80% of the sampled fish were obtained at depths...

Generalized Linear Model results showing factors that influenced the number of sharks detected in the Townsville Reefs. (PDF)

Movement trajectories of three bull sharks monitored in the central Great Barrier Reef. (PDF)

Description of the study reefs (central Great Barrier Reef) and estimated acoustic coverage. Acoustic coverage was calculated as the difference between total and dry reef areas divided by the sum of the detection range area at each reef. This was based on the assumption that each receiver had a maximum detection range of 250 m. (DOCX)

Daily environmental values for the Townsville Reefs, central Great Barrier Reef. Data were obtained from Australian Institute of Marine Science weather stations located at Davies, Rib, Kelso and Dip reefs (http://data.aims.gov.au/). (PDF)

Mixed Effect Model results of factors that influence bull shark (Carcharhinus leucas) residency (RI) in the central Great Barrier Reef. Explanatory variables included month, sex, FL: fork length (cm); Temp: water temperature (°C); Wind: wind speed (km/h); Rain: rain accumulation (mm). (DOCX)

Animation of bull sharks monitored along the East coast of Australia. (GIF)

Animation of bull sharks monitored in the central Great Barrier Reef. (GIF)

Understanding the efficacy of marine protected areas (MPAs) for wide-ranging predators is essential to designing effective management and conservation approaches. The use of acoustic monitoring and network analysis can improve our understanding of the spatial ecology and functional connectivity of reef-associated species, providing a useful approac...

Mercury (Hg) is a non-essential and toxic element that is ubiquitous in the marine environment and biomagnifies through food webs. Given the high trophic position of many elasmobranch species, it is important to quantify potentially harmful trace elements like Hg in their tissues, as this is an indicator of the level of contamination in the ecosyst...

Demersal sharks and rays are common yet vulnerable components of the bycatch in tropical bottom- trawl fisheries. Little is known about the elasmobranch assemblages associated with most of these fisheries, particularly within the eastern tropical Pacific. This study characterized the elasmobranch assemblage associated with the shrimp trawl fishery...

Demersal sharks and rays are common yet vulnerable components of the bycatch in tropical bottom- trawl fisheries. Little is known about the elasmobranch assemblages associated with most of these fisheries, particularly within the eastern tropical Pacific. This study characterized the elasmobranch assemblage associated with the shrimp trawl fishery...

Understanding animal movement decisions that involve migration is critical for evaluating population connectivity, and thus persistence. Recent work on sharks has shown that often only a portion of the adult population will undertake migrations, while the rest may be resident in an area for long periods. Defining the extent to which adult sharks us...

Understanding the efficacy of marine protected areas (MPAs) for wide-ranging predators is essential to designing effective management and conservation approaches. The use of acoustic monitoring and network analysis can improve our understanding of the spatial ecology and functional connectivity of reef-associated species, providing a useful approac...

Movement animation of several bull sharks in the Townsville Reefs, central Great Barrier Reef of Australia

Movement of bull sharks along the East coast of Australia (animation)

Understanding how sharks use coral reefs is essential for assessing risk of exposure to fisheries, habitat loss, and climate change. Despite a wide Indo-Pacific distribution, little is known about the spatial ecology of silvertip sharks (Carcharhinus albimarginatus), compromising the ability to effectively manage their populations. We examined the...

We assessed the effects of the prominent biogeographic (Point Conception and the Peninsula of Baja California) and phylogeographic barriers (Los Angeles Region) of the northeastern Pacific on the population connectivity of the brown smoothhound shark, Mustelus henlei (Triakidae). Data from the mitochondrial control region and six nuclear microsatel...

Understanding movement and connectivity of populations is increasingly important as human and climate change pressures become more pervasive, but can be problematic in difficult to observe species such as large marine predators. We examined the movements of bull sharks, Carcharhinus leucas, using acoustic telemetry arrays along the east coast of Au...

The degree of reef isolation is thought to limit the frequency of long-range dispersals in reef-associated sharks. Therefore, understanding how the behaviour and spatial ecology of a species differ across reef habitats is essential for developing sound conservation approaches. The present study examined the residency, movement and activity space of...

Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve u...

Marine protected areas (MPAs) are thought to be a valuable conservation tool for a wide range of reef-associated species, particularly those that spend a significant amount of time on a single reef. However, MPAs are often designed with little prior knowledge of a species’ spatial ecology and behaviour, and thus their benefits remain unclear. The m...

Bays and estuaries are considered essential fish habitat, yet in many parts of the world, these areas have been degraded or destroyed. In southern California, habitat restoration has become a widely used approach for protecting coastal ecosystems; however, there is little information available on the success of these efforts. Monthly abundance surv...

Shallow intertidal habitats are recognised as critical for larval and juvenile fish, and are often assumed to function as refuge areas where predation risk is reduced. Yet there is growing evidence that suggest these areas may also be regularly inhabited by large bodied fish and be the site of high levels of juvenile fish predation. In the present...

The diet and diel feeding behaviour of the banded guitarfish Zapteryx xyster were examined along the Pacific coast of Costa Rica. A sample of 235 stomachs was collected between March 2010 and December 2011 as part of an ongoing shrimp-trawl by-catch monitoring programme. Samples from multiple day and night periods allowed testing the hypothesis tha...

Stomachs from 511 Raja velezi and 340 Mustelus henlei captured as by-catch in the commercial trawling fishery (2010-2012) were analysed to examine diet composition, ontogenetic shifts and degree of dietary overlap between species life stages in the Pacific Ocean of Costa Rica. Shrimps were the most important prey categories in the diet of R. velezi...

Quantifying fine-scale movement patterns and habitat use of coastal marine fishes has historically required active acoustic tracking techniques, which has limited the habitats and durations over which tagged individuals could be tracked. Development of underwater acoustic-radio arrays (3 receiver time-difference-of-arrival) have allowed for higher...