Effect of temperature and photoperiod on the early development of nudibranch diaulula punctuolata (D’orbigny, 1837) under laboratory conditions [Efecto de la temperatura y el fotoperiodo sobre el desarrollo temprano del nudibranquio Diaulula punctuolata (D’Orbigny, 1837) en condiciones de laboratorio]
Perez-Valdes M.,University of Los Lagos |
Contreras-Guzman R.,Subsecretaria de Pesca
Latin American Journal of Aquatic Research | Year: 2016
Temperature plays an important role in both the development and growth of marine invertebrates; furthermore, it has been observed that photoperiod significantly affects feeding, growth and larval survival. In this study we evaluated the effect of temperatures of 10o and 16oC and photoperiods of 8:16 and 16:8 on early development, hatching and larval survival in the nudibranch Diaulula punctuolata, under laboratory conditions. At 16oC/8:16, hatching occurred between 10 and 11 days post-spawning (dps), with a physiological time of 162.3 ± 10.1 degree day (doC); while at 10oC/8:16, hatching took place between 17 and 20 dps; 200.5 ± 27.4 doC (F = 366.6; P ˂ 0.05). The highest hatching percentage, 82.9%, was obtained at 10oC (F = 16.63; P ˂ 0.05) coinciding with environmental conditions present during the adult collection season. Larvae obtained at 16oC were larger (146.3 ± 0.8 μm) than those at 10oC (140.4 ± 0.5 μm) (F = 212; P ˂ 0.05). Nevertheless, survival time was greater at 10oC/8:16 (21 dps), which could be associated with greater nutrient accumulation during embryonic development. Both embryonic and larval development are dependents on temperature, but not on photoperiod; an increase in temperature from 10º to 16oC, reduced the chronological time required up to hatching by 45.6 ± 3.4%. Photoperiod only affected larval survival at 10oC. © 2016, Escuela de Ciencias del Mar. All rights reserved.
Dellatorre F.G.,CONICET |
Dellatorre F.G.,Brown University |
Amoroso R.,University of Washington |
Saravia J.,Subsecretaria de Pesca |
Aquatic Invasions | Year: 2014
Coastal Patagonia, often regarded as a pristine area of the world, has been invaded by non-indigenous species that are rapidly modifying local ecosystems. One of the most conspicuous invaders is the kelp Undaria pinnatifida. First recorded near the city of Puerto Madryn (Argentina, 42.75°S) in 1992, Undaria’s range has expanded more than five degrees of latitude to the south during the last 15 years. By 2007 it was first detected north of Valdés Peninsula (a natural barrier to dispersal), beginning its northward expansion, and between 2007 and 2011 spread along the coasts of San José and San Matías gulfs at an average rate of ~50 km yr-1. A small population was detected in Mar del Plata (Argentina, 38.04°S) in 2011, more than three degrees of latitude to the north, suggesting a new human-mediated inoculation. A thermal tolerance window is hypothesized based on experimental information and remotely sensed sea-surface temperature (SST) at the latitudinal range limits of U. pinnatifida populations worldwide. The window is defined by average SSTs ranging between-0.6 °C and 16.8 °C in the coldest month, and between 13°C and 28°C in the warmest month. Using climatologic satellite SST from several locations, a potential latitudinal thermal range extending between Puerto Deseado (Argentina, 47.75°S) and Cape Torres (Brazil; 29.35°S) is predicted. Salinity and substrate quality however constrain suitable habitat in the Southwest Atlantic to discrete stretches of coastline, suggesting that the northern potential boundary would be around La Coronilla (33.90°S), on the Uruguayan coast. © 2014 REABIC.
Estimating mortality of black-browed albatross (Thalassarche melanophris, Temminck, 1828) and other seabirds in the Argentinean factory trawl fleet and the use of bird-scaring lines as a mitigation measure
Tamini L.L.,Albatross Task Force Argentina |
Chavez L.N.,Albatross Task Force Argentina |
Gongora M.E.,Subsecretaria de Pesca |
Gongora M.E.,National University of la Patagonia |
And 3 more authors.
Polar Biology | Year: 2015
Seabird bycatch represents one of the main threats to vulnerable seabird populations, particularly albatross and petrels, and requires urgent conservation management interventions at a global scale. We studied seabird mortality associated with demersal factory trawl vessels that target Argentine Hake Merluccius hubbsi along the Argentine Patagonian Shelf and tested the efficacy of bird-scaring lines as a seabird bycatch mitigation measure. From November 2008 to June 2010, dedicated seabird observers recorded three sources of seabird mortality: entanglements with the trawl net; collisions with the trawl cables (corpses hauled aboard); and collisions with trawl cables (birds observed killed or injured). During 141 days and 389 hauls, we recorded 17 seabird species associated with vessels, ten of which interacted with fishing gear. The most vulnerable species was the black-browed albatross (Thalassarche melanophris). From 41 recovered corpses, we identified black-browed albatross mortality rates of 0.013 and 0.093 birds/haul for net entanglement and cable collision (corpses hauled aboard), respectively. From counts of birds killed or injured by cable collisions, we estimate a black-browed albatross mortality rate of 0.237 birds/h. We use official fishing effort data to consider the potential scale of seabird mortality for the entire fleet and identify the main factors contributing to seabird mortality in this fishery. Bird-scaring lines eliminated seabird mortality caused by collisions with trawl cables and are recommended as a short- to medium-term measure to mitigate seabird mortality in this fishery. © 2015 Springer-Verlag Berlin Heidelberg
Squeo F.A.,University of La Serena |
Squeo F.A.,Institute Ecologia y Biodiversidad IEB |
Estades C.,University of Chile |
Bahamonde N.,Academia Chilena de Ciencias |
And 12 more authors.
Revista Chilena de Historia Natural | Year: 2010
Since 1985, the Chilean government with the participation and support of different specialists in plant and animal conservation, started the publication of checklists (i.e. red books) of plant (1985) and animal species (1987) with high to moderate risk of extinction due to human activities (i.e. threatened species). The seven categories of threats used in these publications matched those used by the International Union for the Conservation of Nature (IUCN) in 1982; nonetheless, for the flora there was matching only in five of the categories used. In 1994, the Law 19300 on the General Bases of the Environment established six categories of conservation status. The regulations for the classification of the wild species in Conservation categories, enacted in 2005, defined these six categories, which resulted from a combination of those proposed by the IUCN in 2001 and 1982. The generation of this hybrid system, which is not fully comparable with that of the IUCN (2001) and widely used in the rest of the world, has severely restricted the possibility of classifying species with a threat level lower than "Vulnerable". Further complications were generated due to the definition of conservation categories that appeared in the Laws 19473 (1996) regulating the hunting activity and 20283 (2008) supporting the native forest recovery and forestry development. The Law 20417 (enacted in January 26, 2010) modified the Law 19300 and incorporated the categories recommended by IUCN. Currently, the State requires adapting several legal bodies to advance in the knowledge of the conservation status of the nation's flora and fauna, and consequently, ensure the implementation of effective efforts to protect our biodiversity.
Zevallos D.G.,CONICET |
Tamini L.L.,Albatross Task Force Argentina |
Seco Pon J.P.,CONICET |
Gongora M.E.,Subsecretaria de Pesca |
And 2 more authors.
Hornero | Year: 2012
At least about 70 species of seabirds feed in the waters of the argentinean continental shelf, which is probably the area with the highest biomass of albatrosses in the world. the distribution of these birds at sea generally coincides with commercial fisheries in areas with high marine productivity, so their interactions can be frequent and diverse. the study of the argentine sea considering seabirds as part of an integrated approach represents a challenge. some aspects of the biology of these birds could act as environmental indicators to understand systems, assess their conservation status and analyze their relationships with global processes. although interactions between seabirds and some fishing fleets operating on the patagonian shelf have not yet been addressed, the knowledge of the ecology, behaviour and conservation of this group of birds has increased significantly in the last decade. including ecosystem considerations into fisheries management should contribute to long-term food security and ensure effective conservation and sustainable use of the ecosystem and its resources.
Staig F.,Católica del Norte University |
Hernandez S.,Católica del Norte University |
Hernandez S.,Veritas University of Costa Rica |
Lopez P.,University of Chile |
And 3 more authors.
Revista Brasileira de Paleontologia | Year: 2015
Neogene marine sediments from Chilean geological formations contain a diverse marine fossil fauna. In Chile, the “Norte Chico” (27°S to 32°S) is composed of two important sedimentary marine deposits, the Bahía Inglesa and Coquimbo formations. Diverse vertebrate taxa including fish, birds, mammals and abundant chondrichthyans have been described from Bahía Inglesa Formation. However, the vertebrate fauna from Coquimbo Formation has been poorly documented. Based upon field trips and the analysis of collections from the Coquimbo Formation, the elasmobranch fossil fauna is composed of at least nine taxa, two of which are extinct (Carcharocles megalodon and Carcharodon plicatilis). The rest of the taxa are related with living elasmobranch species that are inhabitants of the Eastern Pacific Ocean and Tropical America coast. © 2015 by the Sociedade Brasileira de Paleontologia.