Doris Oliva

New regulations in Chilean fisheries and aquaculture : ITQ's and Territorial Users Rights

Abstract The large industrial fishery development that turn Chile into the third fishing nation in the world is described, and recent regulatory innovations introduced by new Fishery and Aquaculture legislation are reviewed. In addition to classical Fishery management tools, different types of limited entry systems are now defined in the law and applicable to Chilean fisherie. These for the first time include allocation of resources in the form of Individual Fishing Quotas and Individual Transferable Quotas (IFQs and ITQs). Territorial User’s Rights in Fisheries (TURF’s) were incorporated in the law to enhance self-regulatory practices among artisanal fishermen. Among them, the Areas for Management and Exploitation for Benthic Resources (AME) represent an associative assignment of TURFs. Large-scale zoning is used to re-define Aquaculture Grants and to ritualise the conflicts between Artisanal and Industrial fishermen by establishing the Artisanal Reserve in which small-scale coastal fishermen have Priority Access. Performance of the new management instruments are documented with case studies, for the following fisheries: the loco ( Concholepas concholepas ) a carnivorous snail, keyhole limpets (Fissurella spp.), langostino or squat lobster ( Cervimunida johni ), Black hake ( Dissostichus eleginoides ) and the Yellow prawn ( Pleuroncodes monodon ).

Distribution and abundance of the South American sea lion Otaria flavescens (Carnivora: Otariidae) along the central coast off Chile

Se estimo la distribucion y la abundancia poblacional del lobo marino comun Otaria flavescens en la costa de Chile central durante los meses de enero y febrero de 2007. Adicionalmente, se analizaron los cambios en la abundancia de esta especie durante el periodo 1970-2007. Los censos poblacionales se basaron en fotografias tomadas desde embarcaciones menores o desde avionetas. Se contabilizaron un total de 16301 lobos marinos (IC = 16209-16375) en 33 colonias (6 reproductivas y 27 no reproductivas). Despues de corregir por la proporcion de animales en el agua y por crias no registradas al momento del censo, se estimo una abundancia promedio de 18179 (95 % CI = 17777-18851) lobos marinos en el area de estudio. El analisis de tendencia poblacional presento que desde 1970 a 1985 la abundancia-lobo marino com-mostro una tendencia positiva de aproximadamente 2.1 % ano-1. Sin embargo, entre 1985 a 1997, y entre 1997 a 2007, el numero de lobos marinos muestra una tendencia estable o ligeramente negativa de 0.4 ± 0.1 % ano-1 y 0.5 ± 0.1 % ano-1, respectivamente. Se sugiere que la sobreexplotacion y la declinacion de las principales pesquerias en la zona central de Chife podria haber impactado negativamente la distribucion y abundancia del lobo marino comun en el area de estudio.

Variation in patterns of metal accumulation in thallus parts of Lessonia trabeculata (Laminariales; Phaeophyceae): implications for biomonitoring.

Seaweeds are well known to concentrate metals from seawater and have been employed as monitors of metal pollution in coastal waters and estuaries. However, research showing that various intrinsic and extrinsic factors can influence metal accumulation, raises doubts about the basis for using seaweeds in biomonitoring programmes. The thallus of brown seaweeds of the order Laminariales (kelps) is morphologically complex but there is limited information about the variation in metal accumulation between the different parts, which might result in erroneous conclusions being drawn if not accounted for in the biomonitoring protocol. To assess patterns of individual metals in the differentiated parts of the thallus (blade, stipe, holdfast), concentrations of a wide range of essential and non-essential metals (Fe, Cr, Cu, Zn, Mn, Pb, Cd, Ni and Al) were measured in the kelp Lessonia trabeculata. Seaweeds were collected from three sampling stations located at 5, 30 and 60 m from an illegal sewage outfall close to Ventanas, Chile and from a pristine location at Faro Curaumilla. For the majority of metals the highest concentrations in bottom sediment and seaweed samples were found at the site closest to the outfall, with concentrations decreasing with distance from the outfall and at control stations; the exception was Cd, concentrations of which were higher at control stations. The patterns of metal concentrations in different thallus parts were metal specific and independent of sampling station. These results and the available literature suggest that biomonitoring of metals using seaweeds must take account of differences in the accumulation of metals in thallus parts of complex seaweeds.

Circaritmos de actividad diarios y anuales en el lobo marino común Otaria flavescens (Carnivora: Otariidae) en la zona central de Chile

En otaridos se han estudiado la presencia de circaritmos de actividad sobre la base de cambios en las densidades poblacionales en las loberas. En este trabajo, se estudiaron los ritmos circadiano (24 h) y circanual (1 ano) del lobo marino comun Otaria flavescens en las loberas de Cochoa y Punta Curaumilla en Chile Central. El ritmo circadiano fue estudiado en ambas loberas. En cada una de ellas se realizaron censos cada 45 min durante 3 dias de observacion continuos (72 h). Los resultados demuestran que se produce un aumento del numero de animales en tierra en horarios diurnos y una disminucion en los nocturnos. Dichas fluctuaciones estan asociadas a un ciclo de 24 h, y demuestran la existencia de un ritmo circadiano en estas loberas. El ritmo circanual fue estudiado en la lobera de Cochoa. Para ello se realizaron 145 observaciones durante 3 anos consecutivos (1995-1998). Los resultados muestran un aumento de la poblacion en los meses de otono a primavera, y una disminucion brusca en el verano. Estas fluctuaciones se asocian a un ciclo de un ano, y demuestran la existencia de un ritmo circanual en esta especie.

Environmental assessment in a shallow subtidal rocky habitat: approach coupling chemical and ecological tools

Environmental policy and legislation pursuing the protection of marine ecosystems have commonly considered pollutant content in abiotic matrices. Nevertheless, this approach does not describe the eventual effects on living organisms. The aim of this study was to couple two monitoring tools for environmental diagnostics: the chemical tool, metal concentrations in hard-bottom sediments; and the ecological tool, observations of invertebrate communities inhabiting Lessonia trabeculata holdfasts. The study was conducted during austral summer, in central Chile, in a subtidal ecosystem threatened by a sewage outfall, and was compared with a nearby control zone. Environmental assessment was conducted at three different sites with distances ranging from the outfall to 60 m (there was similar site disposal in control zone). Metal levels in sediments were highest in the site closest to the outfall, decreasing with distance, and were also low in control sites. Changes found in community taxonomic diversity were consistent with the presence of the outfall, especially at 30 m away. The subtidal ecosystem was polluted. It is important to incorporate these multi- and interdisciplinary approaches to environmental research and legislation in order to obtain information that represents effects at different timescales, improves field logistics and truthfully characterises environmental conditions.

Using Satellite Tracking and Isotopic Information to Characterize the Impact of South American Sea Lions on Salmonid Aquaculture in Southern Chile.

Apex marine predators alter their foraging behavior in response to spatial and/or seasonal changes in natural prey distribution and abundance. However, few studies have identified the impacts of aquaculture that represents a spatially and temporally predictable and abundant resource on their foraging behavior. Using satellite telemetry and stable isotope analysis we examined the degree of spatial overlap between the South American sea lion (SASL) and salmon farms, and quantify the amount of native prey versus farmed salmonids in SASL diets. We instrumented eight SASL individuals with SRDL-GPS tags. Vibrissae, hair and skin samples were collected for δ13C and δ15N analyses from five of the tagged individuals and from four males captured in a haul-out located adjacent to salmon farms. Tracking results showed that almost all the foraging areas of SASL are within close proximity to salmon farms. The most important prey for the individuals analyzed was farmed salmonids, with an estimated median (±SD) contribution of 19.7 ± 13.5‰ and 15.3 ± 9.6‰ for hair and skin, respectively. Using vibrissae as a temporal record of diet for each individual, we observed a remarkable switch in diet composition in two SASL, from farmed salmonids to pelagic fishes, which coincided with the decrease of salmon production due to the infectious salmon anemia virus that affected salmon farms in Chile at the end of 2008. Our study demonstrates the usefulness of integrating stable isotope derived dietary data with movement patterns to characterize the impacts of a non-native prey on the foraging ecology of an apex marine predator, providing important applied implications in situations where interactions between aquaculture and wildlife are common.

Diet plasticity of the South American sea lion in Chile: stable isotope evidence

Diet studies of the South American sea lion (SASL) in Chile suggest that this species is an opportun istic and generalist predator whose diet varies depending on the distribution of prey species and spatial and temporal variations in the abundance of these dams. However, these studies have been sporadic, geographically limited and based on stomach content analysis, which does not allow an integral analysis of the composition of the diet of this species and its potential spatial and temporal variability. In this study we analyzed the diet of the SASL in 3 geographic zones of the coast of Chile using analysis of stable isotopes  13 C and  15 N on hair and skin tissues. In the northern zone, the main prey species consumed by SASL were Isacia conceptionis (19.5%) for skin and Cilus gilberti (23.3%) for hair; in the central zone were Thyrsites atun (40.1%) for skin and Strangomera bentincki (31.1%) for hair, whereas in the southern zone the main species were pelagic fish (such as T. atun and Trachurus murphyi, 20.8%) for skin and farm-raised salmonids (20.7%) for hair analysis. These differences indicate variation in the composition of its diet. Variations between the analyzed tissues and also with previous studies suggest that this species is capable of adapting to intra- and inter-annual variations in the presence/absence of its prey.

Testing Bergmann’s rule and the Rosenzweig hypothesis with craniometric studies of the South American sea lion

We tested the validity of Bergmann’s rule and Rosenzweig’s hypothesis through an analysis of the geographical variation of the skull size of Otaria flavescens along the entire distribution range of the species (except Brazil). We quantified the sizes of 606 adult South American sea lion skulls measured in seven localities of Peru, Chile, Uruguay, Argentina, and the Falkland/Malvinas Islands. Geographical and environmental variables included latitude, longitude, and monthly minimum, maximum, and mean air and ocean temperatures. We also included information on fish landings as a proxy for productivity. Males showed a positive relationship between condylobasal length (CBL) and latitude, and between CBL and the six temperature variables. By contrast, females showed a negative relationship between CBL and the same variables. Finally, female skull size showed a significant and positive correlation with fish landings, while males did not show any relationship with this variable. The body size of males conformed to Bergmann’s rule, with larger individuals found in southern localities of South America. Females followed the converse of Bergmann’s rule at the intraspecific level, but showed a positive relationship with the proxy for productivity, thus supporting Rosenzweig’s hypothesis. Differences in the factors that drive body size in females and males may be explained by their different life-history strategies. Our analyses demonstrate that latitude and temperature are not the only factors that explain spatial variation in body size: others such as food availability are also important for explaining the ecogeographical patterns found in O. flavescens.

Seasonal variation in the abundance of South American sea lions Otaria flavescens (Shaw, 1800) in Chañaral Island, Reserva Nacional Pingüino de Humboldt, Chile

Desde enero de 2007 y hasta marzo de 2008 se analizo la variacion de la abundancia del lobo marino comun Otaria flavescens en la lobera reproductiva Isla Chanaral, de acuerdo al sexo, clase de edad y estacion reproductiva. El mayor numero de lobos marinos en la lobera se registro durante el periodo reproductivo. Esta variacion se debio principalmente a la fluctuacion del numero de hembras, ya que esta clase de edad fue la mas importante en la colonia y mostro un aumento en su abundancia durante este periodo. No se registraron fluctuaciones estacionales en el numero de machos adultos, machos subadultos y juveniles. La proporcion de sexos durante la estacion reproductiva estuvo fuertemente sesgada hacia las hembras, mientras que fue cercana a 1:1 durante el resto del ano. Este estudio demuestra que la variacion en la abundancia y composicion por sexo y clase de edad del lobo marino comun en Isla Chanaral se relaciona principalmente con la actividad reproductiva.

Effect of stocking density and diet on growth and survival of post-larvae of the taquilla clam Mulinia edulis cultivated in sand in a hatchery

Con el objeto de contribuir al desarrollo de la tecnologia para el cultivo comercial de la almeja taquilla Mulinia edulis, se determino el efecto de la densidad de cultivo y el tipo de dieta en el crecimiento y sobrevivencia de las postlarvas. Cultivos larvales de 14 dias, dieron origen a postlarvas que fueron cultivadas en sistemas cerrados con fondo de arena por 30 dias, a densidades de 5, 10 y 20 postlarvas cm-2. Para determinar el efecto del tipo de dieta se ofrecieron 3 dietas monoespecificas: Isochrysis aff galbana (clon T-ISO), Phaeodactylum tricornotum y Tetraselmis suecica y 2 dietas mixtas: I. galbana (clon T-ISO) (50%) - P. tricornotum (50%) y I. galbana (clon T-ISO) (33%) - P. tricornotum (33%) - T. suecica (33%) a una racion fija de 100.000 cel ml-1 dia-1. El cultivo a una densidad 5 postlarvas cm-2 genero la mayor longitud valvar que fue de 1707 ± 200 µm a una edad de 44 dias. Las postlarvas alimentadas con Isochrysis galbana (clon T-ISO) alcanzaron las mayores longitudes valvares, 2225 ± 430 µm a una edad de 50 dias. La supervivencia de las postlarvas fue alrededor del 50% y no fue afectada por los diferentes niveles de parametros analizados (densidad de cultivo y dieta).