Spatio-temporal migratory dynamics of Jasus frontalis (Milne Edwards, 1837) in Alexander Selkirk Island, Juan Fernández archipelago, Chile
Román, C., Ernst, B., Thiel, M., Manríquez, P. and Chamorro, J.
Knowledge about the spatial patterns and movements of crustaceans has gained importance since the creation of marine protected areas and the development of spatial management for benthic ecosystems. The Juan Fernández spiny lobster (Jasus frontalis) is an endemic marine species and most valuable resource that exhibits migratory dynamics in a highly spatially regulated fishery. To study movement patterns around Alexander Selkirk Island, a mark-recapture program was implemented in 2008, when approximately 7000 non-commercial (undersized) lobsters were tagged and followed for nearly 14 months. Using quantitative georeferenced data, this study revealed spatial structuring of Juan Fernández spiny lobster and tested hypotheses about alongshore and inshore-offshore movements. Eight clusters were identified around Alexander Selkirk Island, with moderate time-varying connectivity between them. Seasonal inshore-offshore movements were detected all around the island, but more conspicuously to the north. Average travelling distance was 1.2 km (1.7 sd). Our results confirmed that towards the end of austral spring males and females embark in a seasonal offshore migration to deeper waters, returning to shallower waters only during winter. These findings quantitatively consolidate the conceptual migratory model that local fishermen had already inferred for this resource from about a century of sustainable fishing.
Referencia APA: Román, C., Ernst, B., Thiel, M., Manríquez, P. and Chamorro, J. (2018). Spatio-temporal migratory dynamics of Jasus frontalis (Milne Edwards, 1837) in Alexander Selkirk Island, Juan Fernández archipelago, Chile. PLOS ONE, 13(7), p.e0200146. https://doi.org/10.1371/journal.pone.0200146
Heritability, genetic correlations and genotype-environment interactions for growth and survival of larvae and post-larvae of the Caribbean scallop, Argopecten nucleus (Mollusca: Bivalvia)
Barros, J., Winkler, F. and Velasco, L.
The Caribbean scallop Argopecten nucleus is a species with a great potential for commercial aquaculture in the Caribbean given its fast growth and the availability of culture technology. However, its production relies completely on hatchery-reared seed, and the survival in early stages, particularly during the settling process, is the main limitation for this activity to become cost effective. Thus, in order to assess the feasibility of improving survival of larvae and post-larvae of A. nucleus through genetic selection without affecting growth, it was estimated the heritability and the genotype-environment interactions for such traits, as well as the genetic correlations between them. These parameters were estimated based on intraclass correlations of 40 full-sib families (10 half-sib families) at 1, 11 and 75 days post fertilization. Heritability values were very high for the post-larvae survival (0.49), while it was low and not significant for larvae survival (≤0.07) and medium to high for growth traits of larvae and post-larvae (>0.3). The traits analyzed in post-larvae exhibited significant genotype-environment interactions in relation to culture depth in the sea. No significant genetic correlations between the measured traits were found. The results suggest the existence of an important genetic component in the variation of post-larval survival, and larval and post-larval growth, as well as a high potential response to direct genetic selection, especially for post-larval survival (50% increase per generation), without affecting the growth traits.
Palabras claves: Shell length, Shell height, Post-larvae recovery, Genetic improvement, Selective breeding, Genetic gain, Pectinid
Referencia APA: Barros, J., Winkler, F. and Velasco, L. (2018). Heritability, genetic correlations and genotype-environment interactions for growth and survival of larvae and post-larvae of the Caribbean scallop, Argopecten nucleus (Mollusca: Bivalvia). Aquaculture, 495, pp.948-954.
High acclimation potential in floating Macrocystis pyrifera to abiotic conditions even under grazing pressure – a field study
Rothäusler, E., Reinwald, H., López, B., Tala, F. and Thiel, M.
The persistence of floating seaweeds, which depends on abiotic conditions but also herbivory, had previously been mostly tested in outdoor mesocosm experiments. In order to investigate if the obtained mesocosm results of high seaweed persistence under natural environmental conditions and under grazing pressure can be extrapolated to field situations, we conducted in situ experiments. During two summers (2007 and 2008), Macrocystis pyrifera was tethered (for 14 d) to lines in the presence and absence of the amphipod Peramphithoe femorata at three sites (Iquique, Coquimbo, Calfuco). We hypothesized that grazing damage and seaweed persistence vary among sites due to different abiotic factors. By incubating the sporophytes in mesh bags, we were either able to isolate (grazing) or exclude (control) amphipods. To test for a mesh bag artifact, a set of sporophytes was incubated without mesh bags (natural). Mesh bags used to exclude herbivores influenced sporophyte growth and physiological performance. The chlorophyll a (Chl a) content depended largely on grazers and grazed sporophytes grew less than natural and control sporophytes within the two summers. A decrease in Chl a content was found for the sites with the highest prevailing irradiances and temperatures, suggesting an efficient acclimation to these sea surface conditions. Our field-based results of sporophyte acclimation ability even under grazing pressure widely align with previous mesocosm results. We conclude that M. pyrifera and other temperate floating seaweeds can function as long-distance dispersal vectors even with hitchhiking mesoherbivores.
Palabras claves: Macrocystis pyrifera; Peramphithoe femorata; amphipods; herbivory; kelp rafts; solar radiation; temperature.
Referencia APA: Rothäusler, E., Reinwald, H., López, B., Tala, F. and Thiel, M. (2018). High acclimation potential in floating Macrocystis pyrifera to abiotic conditions even under grazing pressure - a field study. Journal of Phycology, 54(3), pp.368-379.
Geographic variation in biochemical and physiological traits of the red seaweeds Chondracanthus chamissoi and Gelidium lingulatum from the south east Pacific coast
Véliz, K., Chandía, N., Karsten, U., Lara, C. and Thiel, M.
Diverse phenotypic characteristics have evolved in seaweeds to cope with environmental stress, but these traits can vary among populations of the same species especially if these are distributed along environmental gradients. In this study, natural populations of the carrageenophyte Chondracanthus chamissoi and the agarophyte Gelidium lingulatum from a latitudinal gradient along the Chilean coast (between 20° S and 41° S) were compared. We determined physiological and biochemical traits in field and culture samples. Sulfated polysaccharide contents ranged from 15.4 to 52.7% dry weight (DW) in C. chamissoi and from 10.9 to 25.1% DW in G. lingulatum. Carrageenan amounts were higher in gametophytes than tetrasporophytes and were also, depending on life cycle phase, negatively correlated with the geographic variation of temperature, photosynthetically active radiation (PAR), and chlorophyll a (Chl a), whereas agar showed no significant correlation with these variables. The UV-absorbing mycosporine-like amino acids (MAAs) shinorine and palythine in both species ranged from 0.8 to 6.8 mg g−1 DW and these contents were positively correlated to PAR and Chl a levels at the sampling site. In C. chamissoi variation among populations in their photosynthetic characteristics, pigment concentrations, antioxidant capacity, and MAA contents were persistent after acclimation under common-garden conditions, suggesting ecotypic differentiation in this species. Contrary, G. lingulatum seems to have a more generalist strategy because differences after cultivation were observed only in some photosynthetic parameters and phycobiliprotein concentration. This study confirms that intraspecific differences in phenotypic traits along the same geographic area are strongly dependent on species and life cycle phases.
Palabras claves: Rhodophyta, Carrageenans, Agar, Mycosporine-like amino acids, Ecotypes, Chile
Referencia APA: Véliz, K., Chandía, N., Karsten, U., Lara, C. and Thiel, M. (2018). Geographic variation in biochemical and physiological traits of the red seaweeds Chondracanthus chamissoi and Gelidium lingulatum from the south east Pacific coast. Journal of Applied Phycology, 31(1), pp.665-682. https://doi.org/10.1007/s10811-018-1532-0
Low prevalence of microplastic contamination in planktivorous fish species from southeast Pacific Ocean
Ory, N., Chagnon, C., Felix, F., Fernández, C., Ferreira, J., Gallardo, C., Garcés Ordóñez, O., Henostroza, A., Laaz, E., Mizraji, R., Mojica, H., Murillo Haro, V., Ossa Medina, L., Preciado, M., Sobral, P., Urbina, M. and Thiel, M.
The gut contents of 292 planktivorous fish, from four families (Atherinopsidae, Clupeidae, Engraulidae and Scombridae) and seven species, captured along the coast of the southeast Pacific, were examined for microplastic contamination. Only a small fraction of all studied fish (2.1%; 6 individuals) contained microplastic particles in their digestive tract. Microplastics found were degraded hard fragments and threads, ranging from 1.1 to 4.9 (3.8 ± SD 2.4) mm in length, and of various colours, which suggests that the planktivorous fish species examined herein did not capture microplastics on the basis of their colour. The low prevalence of microplastic contamination in planktivorous fishes found in this study suggests that the risk of accidental ingestion by these species might be limited in the coastal upwelled waters of the southeast Pacific, perhaps due to small human population and highly dynamic oceanographic processes.
Palabras claves: Microplastic contamination, Planktivorous fish, Southeast Pacific Ocean, Upwelling systems, Humboldt Current System
Referencia APA: Ory, N., Chagnon, C., Felix, F., Fernández, C., Ferreira, J., Gallardo, C., Garcés Ordóñez, O., Henostroza, A., Laaz, E., Mizraji, R., Mojica, H., Murillo Haro, V., Ossa Medina, L., Preciado, M., Sobral, P., Urbina, M. and Thiel, M. (2018). Low prevalence of microplastic contamination in planktivorous fish species from the southeast Pacific Ocean. Marine Pollution Bulletin, 127, pp.211-216. https://doi.org/10.1016/j.marpolbul.2017.12.016
No reef-associated gradient in the infaunal communities of Rapa Nui (Easter Island) – Are oceanic waves more important than reef predators?
Gusmao, J., Lee, M., MacDonald, I., Ory, N., Sellanes, J., Watling, L. and Thiel, M.
Reef-associated predators are thought to influence the distribution of invertebrates of surrounding sediment habitats. In this study, we analyzed the predation pressure and the distributional patterns of macro- and meiofaunal assemblages in soft sediments surrounding two coral reef sites at Rapa Nui (Easter Island), in the central South Pacific. We tested the hypothesis that reef-associated predators negatively affect sediment-dwelling invertebrates, causing macro- and meiofauna to be less abundant and diverse in soft sediments near the reefs. As expected, predation intensity was greater nearer the reef than farther away, but macro- and meiofaunal assemblages did not differ significantly with distance from the reef. Taxon richness of macro- and meiofaunal assemblages were similar irrespective of distance from the reef. Only meiofauna showed significant variation in total abundance with distance from the reef, but this trend was not consistent between the two study sites. No gradient in sediment texture was observed with distance from the reef. Underwater video recordings at one study site also revealed that local hydrodynamics cause frequent disturbance and resuspension of the upper sediment layers. Our results suggest that soft-sediment assemblages are constantly reshuffled by oceanic waves, thereby blurring the potential effects of predation on invertebrate assemblages closer to the reef.
Palabras claves: Easter islandSoft-bottom assemblagesMacrofaunaMeiofaunaInfaunal halosReef fishesPredation
Referencia APA: Gusmao, J., Lee, M., MacDonald, I., Ory, N., Sellanes, J., Watling, L. and Thiel, M. (2018). No reef-associated gradient in the infaunal communities of Rapa Nui (Easter Island) – Are oceanic waves more important than reef predators?. Estuarine, Coastal and Shelf Science, 210, pp.123-131. https://doi.org/10.1016/j.ecss.2018.06.019
Spatio-temporal variation of anthropogenic marine debris on Chilean beaches
Hidalgo-Ruz, V., Honorato-Zimmer, D., Gatta-Rosemary, M., Nuñez, P., Hinojosa, I. and Thiel, M.
We examined the hypothesis that in an emerging economy such as Chile the abundances of Anthropogenic Marine Debris (AMD) on beaches are increasing over time. The citizen science program Científicos de la Basura (“Litter Scientists”) conducted three national surveys (2008, 2012 and 2016) to determine AMD composition, abundance, spatial patterns and temporal trends. AMD was found on all beaches along the entire Chilean coast. Highest percentages of AMD in all surveys were plastics and cigarette butts, which can be attributed to local sources (i.e. beach users). The Antofagasta region in northern Chile had the highest abundance of AMD compared with all other zones. Higher abundances of AMD were found at the upper stations from almost all zones. No significant tendency of increasing or decreasing AMD densities was observed during the 8 years covered by our study, which suggests that economic development alone cannot explain temporal trends in AMD densities.
Palabras claves: Anthropogenic marine debrisBeachesCitizen scienceTemporal trendsAntofagastaEconomic development
Referencia APA: Hidalgo-Ruz, V., Honorato-Zimmer, D., Gatta-Rosemary, M., Nuñez, P., Hinojosa, I. and Thiel, M. (2018). Spatio-temporal variation of anthropogenic marine debris on Chilean beaches. Marine Pollution Bulletin, 126, pp.516-524. http://dx.doi.org/10.1016/j.marpolbul.2017.11.014
Breeding of the south american tern (Sterna hirundinacea) on anchored boats in Coquimbo, northern Chile
Portflitt-Toro, M., Miranda-Urbina, D., Fernández, C., Luna, N., Plaza, P., Serratosa, J., Thiel, M., Luna-Jorquera, G.
Abstract · We report the breeding attempt of South American Terns (Sterna hirundinacea) on three boats in
Coquimbo, northern Chile. The first breeding attempt was reported in winter 2011 where at least one chick fledged. From April to June 2015, all nests on the boats were monitored. We recorded eggs and chicks during May and early June. However, towards the end of June, no eggs or chicks were recorded in the nests, and a Chimango Caracara (Phalcoboenus chimango) was observed preying on chicks in one nest. In April and May 2017, breeding attempts on boats were also monitored and nests with eggs and one chick were recorded. However, at the end of May all nests were empty. This unusual nesting site for South American Terns is apparently regularly used in the area despite its virtually null breeding success.
Resumen · Reproducción del Gaviotín Sudamericano (Sterna hirundinacea) en botes anclados en Coquimbo, norte de Chile
Reportamos el intento de reproducción del Gaviotín Sudamericano (Sterna hirundinacea) sobre tres botes en Coquimbo, norte de Chile. Un primer intento de reproducción para esta zona se registró en invierno de 2011, donde al menos un pollo dejó un nido como volantón. Entre Abril y Junio de 2015 monitoreamos los nidos en los botes de manera más intensiva. Registramos huevos y pollos durante Mayo y principios de Junio. Sin embargo, a finales de Junio, no registramos huevos en los nidos y observamos un Tiuque (Phalcoboenus chimango) depredar sobre los pollos. En Abril y Mayo de 2017, monitoreamos otros intentos de reproducción y registramos un pollo y nidos con huevos. Sin embargo, a finales de Mayo, esos nidos estaban vacíos. Este inusual sitio de nidificación parece ser utilizado de forma recurrente por el Gaviotín Sudamericano, a pesar del aparente casi nulo éxito reproductivo.
Palabras claves: Anchored boats, Chile, Nesting, Predation, South American Tern
Referencia APA: Portflitt-Toro, M., Miranda-Urbina, D., Fernández, C., Luna, N., Plaza, P., Serratosa, J., Thiel, M., Luna-Jorquera, G. (2018). Breeding of the south american tern (Sterna hirundinacea) on anchored boats in Coquimbo, northern Chile. Ornitología Neotropical 29: 187–191.
Impacts of Marine Plastic Pollution From Continental Coasts to Subtropical Gyres—Fish, Seabirds, and Other Vertebrates in the SE Pacific.
Thiel, M., Luna-Jorquera, G., Álvarez-Varas, R., Gallardo, C., Hinojosa, I., Luna, N., Miranda-Urbina, D., Morales, N., Ory, N., Pacheco, A., Portflitt-Toro, M. and Zavalaga, C.
Anthropogenic Marine Debris (AMD) in the SE Pacific has primarily local origins from land-based sources, including cities (coastal and inland), beach-goers, aquaculture, and fisheries. The low frequency of AMD colonized by oceanic biota (bryozoans, lepadid barnacles) suggests that most litter items from coastal waters of the Humboldt Current System (HCS) are pulled offshore into the South Pacific Subtropical Gyre (SPSG). The highest densities of floating micro- and macroplastics are reported from the SPSG. An extensive survey of photographic records, unpublished data, conference proceedings, and published studies revealed interactions with plastics for 97 species in the SE Pacific, including 20 species of fish, 5 sea turtles, 53 seabirds, and 19 marine mammals. Sea turtles are most affected by interactions with plastics, underlined by the fact that 4 of the 5 species suffer both from entanglement and ingestion. Reports gathered in this review suggest that interactions along the continental coast are mostly via entanglement. High frequencies of microplastic ingestion have been reported from planktivorous fish and seabirds inhabiting the oceanic waters and islands exposed to high densities of microplastics concentrated by oceanic currents in the SPSG. Our review also suggests that some species from the highly productive HCS face the risk of negative interactions with AMD, because food and plastic litter are concentrated in coastal front systems. In order to improve the conservation of marine vertebrates, especially of sea turtles, urgent measures of plastic reduction are needed.
Palabras claves: anthropogenic marine debris, impacts, biota-litter interactions, entanglement, microplastic ingestion
Referencia APA: Thiel, M., Luna-Jorquera, G., Álvarez-Varas, R., Gallardo, C., Hinojosa, I., Luna, N., Miranda-Urbina, D., Morales, N., Ory, N., Pacheco, A., Portflitt-Toro, M. and Zavalaga, C. (2018). Impacts of Marine Plastic Pollution From Continental Coasts to Subtropical Gyres—Fish, Seabirds, and Other Vertebrates in the SE Pacific. Frontiers in Marine Science, 5. https://doi.org/10.3389/fmars.2018.00238
Assessing potential Argentine Ant recruitment to pipping eggs in the Red-tailed Tropicbird on Rapa Nui (Easter Island)
Varela, A., Luna, N., & Luna-Jorquera, G.
The invasive Argentine Ant, Linepithema humile, is known to prey on land bird chicks, but there are few reports of the ants’ impacts on breeding seabirds. We conducted a manipulative study using hen eggs to estimate the potential Argentine Ant recruitment to pipping eggs in the Red-tailed Tropicbird, Phaethon rubricauda, at Rapa Nui (Easter Island), Chile. Hen eggs were experimentally opened to simulate pipping eggs and control eggs were left unopened. The eggs were monitored for 90 min. The time elapsed until the arrival of the first ant did not differ between experimental and control eggs. None of the control eggs were visited by more than two ants. In contrast, the inferred cumulative number of ants that arrived at experimental eggs varied from 1 to >450. Simulated pipping eggs attracted a high number of ants in a short period of time, and the probability of an egg being attacked by ants after 5 and 60 min of exposure was 75% and 99%, respectively. A long-term monitoring study is needed to determine the actual Argentine Ant recruitment rate on pipping eggs, and the potential effects on the post-fledging survival rate of this native seabird which is threatened by a number of introduced species.
Palabras claves: Invasive ants, Linepithema humile, breeding seabirds, Phaethon rubricauda, oceanic islands, south-eastern Pacific Ocean
Referencia APA: Varela, A., Luna, N., & Luna-Jorquera, G. (2018). Assessing potential Argentine Ant recruitment to pipping eggs in the Red-tailed Tropicbird on Rapa Nui (Easter Island). Emu - Austral Ornithology, 1-5. doi: 10.1080/01584197.2018.1464372
Capture, swallowing, and egestion of microplastics by a planktivorous juvenile fish
Ory, N., Gallardo, C., Lenz, M., & Thiel, M.
Microplastics (<5 mm) have been found in many fish species, from most marine environments. However, the mechanisms underlying microplastic ingestion by fish are still unclear, although they are important to determine the pathway of microplastics along marine food webs. Here we conducted experiments in the laboratory to examine microplastic ingestion (capture and swallowing) and egestion by juveniles of the planktivorous palm ruff, Seriolella violacea (Centrolophidae). As expected, fish captured preferentially black microplastics, similar to food pellets, whereas microplastics of other colours (blue, translucent, and yellow) were mostly co-captured when floating close to food pellets. Microplastics captured without food were almost always spit out, and were only swallowed when they were mixed with food in the fish's mouth. Food probably produced a ‘gustatory trap’ that impeded the fish to discriminate and reject the microplastics. Most fish (93% of total) egested all the microplastics after 7 days, on average, and 49 days at most, substantially longer than food pellets (<2 days). No acute detrimental effects of microplastics on fish were observable, but potential sublethal effects of microplastics on the fish physiological and behavioural responses still need to be tested. This study highlights that visually-oriented planktivorous fish, many species of which are of commercial value and ecological importance within marine food webs, are susceptible to ingest microplastics resembling or floating close to their planktonic prey.
Palabras claves: Microplastic ingestion, Planktivorous fish, Juvenile, Seriolella violacea, Laboratory experiments, Microplastic egestion
Referencia APA: Ory, N., Gallardo, C., Lenz, M., & Thiel, M. (2018). Capture, swallowing, and egestion of microplastics by a planktivorous juvenile fish. Environmental Pollution, 240, 566-573. doi: 10.1016/j.envpol.2018.04.093
Factors affecting the operational interaction between the South American sea lions and the artisan gillnet fishery in Chile
Sepúlveda, M., Martínez, T., Oliva, D., Couve, P., Pavez, G., & Navarro, C., Stehlik, M., Durán, L.R., Luna-Jorquera, G.
The South American sea lion (SASL, Otaria byronia) is one of the species of pinnipeds that display the strongest level of conflict with fishing activities throughout its distribution range. However, little is known about potential temporal and/or spatial variations in the magnitude and effects of SASL and fishing interactions over an entire year and at different sites simultaneously. This study examines the factors that affect the intensity of the operational interaction between SASL and the artisan gillnet fishery in central Chile. Between 2014 and 2016, a total of 145 hauls at three artisan fishing coves were analyzed. South American sea lion interactions were observed in 82 of the 145 (56.6%) hauls analyzed, most frequently at the coves of San Antonio and El Membrillo. From the examined factors, Predation per Unit Effort increased with the number of SASL, however it decreased both during the summer and with greater distance from the nearest SASL colony. Artisan deterrent systems used by fishermen were found to be inefficient in avoiding the interactions with sea lions. Although the intensity of the interaction has increased in recent years (compared with previous studies in the area), the observed Catch per Unit Effort did not differ significantly during fishing trips with or without interaction, indicating that SASL is not a determining factor in the variation of artisan fishery catches. These results demonstrate that the intensity of interactions is not produced at random but rather it is related to factors that obey biological and ecological aspects of the SASL. These factors should be considered for the development of effective actions to prevent, or at least to reduce the interaction between SASL and artisan fisheries.
Palabras claves: Fisheries, Pinnipeds, Operational interaction, Chile, Gillnet
Referencia APA: Sepúlveda, M., Martínez, T., Oliva, D., Couve, P., Pavez, G., & Navarro, C., Stehlik, M., Durán, L.R., Luna-Jorquera, G. (2018). Factors affecting the operational interaction between the South American sea lions and the artisan gillnet fishery in Chile. Fisheries Research, 201, 147-152. doi: 10.1016/j.fishres.2018.01.014