Margarita Brandt

Universidad San Francisco de Quito (USFQ) · College of Biological and Environmental Sciences

Yellowfin tuna, Thunnus albacares, is an important global fishery and of particular importance in the Eastern Pacific Ocean (EPO). According to the 2019 Inter-American Tropical Tuna Commission (IATTC) assessment, yellowfin tuna within the EPO is a single stock, and is being managed as one stock. However, previous studies indicate site fidelity, or...

Sea stars (class Asteroidea) can play powerful and wide-ranging roles as consumers of algae and other prey in benthic ecosystems worldwide. In the Galápagos rocky subtidal zone, sea stars are abundant and diverse, but their distribution, feeding habits and ecological impacts have received little attention. We compared diets and distributions of the...

Increased standing macroalgal biomass in upwelling zones is generally assumed to be the result of higher nutrient flux due to upwelled waters. However, other factors can strongly impact macroalgal communities. For example, herbivory and temperature, via their effects on primary producers and the metabolic demands of consumers, can also influence ma...

The benthic marine algae of the mainland coast of Ecuador are poorly known mainly due to a lack of collections. Currently, DNA barcoding is the preferred method to identify species of benthic marine algae worldwide, as morpho-anatomical characters are inadequate to distinguish many species of macroalgae. We used the red algal barcode rbcL-3P to ide...

DNA sequencing of the plastid encoded rbcL gene supported by morpho-anatomical features reveals Gracilaria parva sp. nov. from Panama and Ecuador in the tropical eastern Pacific Ocean. In the rbcL phylogram, G. parva occurs in a clade sister to the western Atlantic species G. galatensis. Morphologically and anatomically, G. parva is distinguished f...

The responses of ectothermic organisms to changes in temperature can be modified by acclimatization or adaptation to local thermal conditions. Thus, the effect of global warming and the deleterious effects of extreme heating events (e.g., heatwaves) on the metabolism and fitness of ectotherms can be population specific and reduced at warmer sites....

La pesca en las Islas Galápagos representa una fuente importante de ingresos para la comunidad galapagueña. La actividad pesquera en las islas es estrictamente artesanal e incluye la pesca de quitones (Radsia goodallii y Radsia sulcatus), como una actividad complementaria a sus actividades cotidianas. El recurso quitón ha sido consumido a manera de...

Sea stars (class Asteroidea) can play powerful and wide-ranging roles as consumers of algae and prey items in benthic ecosystems worldwide. In the Galápagos rocky subtidal zone, sea stars are abundant and diverse but their distribution, feeding habits and ecological impacts have received little attention. We compared diets and distributions across...

En las Galápagos existen 19 especies de quitones, siete de las cuales son endémicas y una de ellas lo "suficientemente" abundante para soportar una pesquería con potencial económico: la canchalagua lisa, Radsia goodallii. Esta especie está incluida en el calendario pesquero de la Reserva Marina Galápagos, sin embargo, no presenta regulación específ...

We present the first official record of the by-the-wind-sailor ( Velella velella ) for Ecuador. Twelve individuals were found along different beaches of San Cristóbal and Santa Cruz Islands in Galápagos Archipelago, Ecuador. These sightings may be influenced by El Niño Southern Oscillation events.

Eastern tropical Pacific (ETP) coral habitats host functionally complex biological communities. Corals and their associated biota, from charismatic reef fishes to cryptic invertebrate infauna, drive and maintain diverse ecosystem functioning in reef environments. This chapter provides a photographic guide to key and otherwise notable species presen...

This chapter reviews and evaluates coral reef conservation strategies along the eastern tropical Pacific (ETP), a narrow biogeographic region on the Pacific American coast that extends from southern Baja California, Mexico to northern Peru, including several oceanic islands. The ETP is a natural laboratory, a model for understanding the development...

Sponges are permanently attached to the substrate. Due to their internal system composed of pores, canals, and chambers, their bodies circulate water with dissolved organic material or plankton that is assimilated by the animal. For marine species distribution data cited in the CDF Galapagos Checklists refer to the five main bioregions of the archi...

We investigated the current patterns of diversity by country and by class of echinoderms, and analyzed their biogeographical, depth, and habitat or substratum affinities, using the database of the appendix of this book. Traditionally, the area has been divided into five biogeographical Regions and nine Provinces that cover a wide climate range. Cur...

This chapter presents a summary of studies on echinoderms on the Ecuadorian continental shelf and at the Galápagos Islands. The geographic, climatic and oceanographic contexts, as well as the general characteristics of ecosystems and communities are discussed first to better understand the diversity of echinoderms and their distribution in Ecuador....

Theory and experiments indicate that changes in consumer diversity affect benthic community structure and ecosystem functioning. Although the effects of consumer diversity have been tested in the laboratory and the field, little is known about effects of consumer diversity in the subtidal zone, one of the largest marine habitats. We investigated th...

Although sea urchins can strongly influence the structure of benthic communities and are abundant in the Galápagos Islands, factors mediating predation on urchins have not been studied experimentally. Here, we examine how habitat structure and behavioral patterns of prey influence predation on the pencil urchin Eucidaris galapagensis, an abundant g...

Comparisons between historical and recent ecological datasets indicate that shallow reef habitats across the central Galapagos Archipelago underwent major transformation at the time of the severe 1982/1983 El Niño warming event. Heavily grazed reefs with crustose coralline algae (‘urchin barrens’) replaced former macroalgal and coral habitats, resu...

Background/Question/Methods . Theory suggests that non-linear shifts in ecosystems occur as thresholds are exceeded, but most empirical studies of El Nino impacts in marine systems describe linear losses of biomass, abundance or diversity. To understand the influence of ENSO's, upwelling and local biotic processes shaping rocky subtidal communities...

Background/Question/Methods Most efforts in understanding how biodiversity influences ecosystem functioning have come from experimental work performed under highly controlled conditions of laboratories and mesocosms. Of the biodiversity and ecosystem functioning (BEF) studies examining the effects of marine diversity of one trophic level on funct...

Salt marshes are frequently exposed to storm overwashes resulting in large deposits of sand and wrack at the margin of the high marsh and sand dune communities. On Cape Cod, MA, these disturbance-generated areas are dominated by burrows of the crab Uca pugilator and by nest entrances of the ants Formica subsericea and Tetramorium caespitum. We mimi...

Our understanding of how communities are regulated diminishes with increasing spatial scale. Because oceanographic processes supply food, transport propagules, and set abiotic conditions across broad areas, they may explain metacommunity and food web functioning on large scales. Here we test for bottom-up manifestations of an oceanographic process,...

Red algae are predominantly marine organisms that inhabit the high intertidal to deep subtidal zone. They are mostly multicellular, filamentous or pseudoparenchymatous, branched or unbranched, cylindrical to compressed or foliaceous. Many species are microscopic, unicellular or short-filamentous; very few species are larger, macroscopic algae. In a...

Marine annelids are worm-shaped, i.e., they are bilaterally symmetrical, and lack extremities. Their bodies are soft and typically at least three times as long as wide, divided into ring-shaped segments.As adults they generally occur in the littoral zone, but the majority of Galapagos species have thus far been found only as larvae during CDF zoopl...

Fish are aquatic vertebrates with gills. They are exothermic animals, meaning their body temperature varies with the temperature of their environment. Taxonomically they can be divided into two classes, Chondrichthyes have a backbone made from cartilage, and Actinoperygii have a bony spine. Almost all fish have scales that protect their body. In ge...