Paula Casanovas

• Doctor of Philosophy
• Analyst at Cawthron Institute

King salmon is important for aquaculture in New Zealand, contributing significant economic value. Fish health is a priority for the industry, and the change in the health status of king salmon needs to be accurately detected at the earliest possible stage. Many factors affect the health of king salmon, such as temperature. Identifying the key featu...

King (Chinook) salmon is the only salmon species farmed in Aotearoa New Zealand and accounts for over half of the world's production of king salmon. Determining the health status of king salmon effectively is important for farming. However, it is a challenging task due to the complex biotic and abiotic factors that influence health. Evolutionary ma...

Simple Summary Aquaculture plays a key role in many emerging economies. Sources of fish for human consumption now exceed those from capture fisheries. However, the high cost of food to feed fish limits investment returns. Physiological inefficiencies in the way fish digest and assimilate nutrients and energy from food can be improved to lower the a...

Feed conversion ratio (FCR) is the ratio between feed intake and weight gain. By improving FCR within a species, feed intake can be reduced for the same amount of growth, thus reducing feed costs and environmental impacts. To enable selection for improved FCR, it is important to understand how FCR differs within a species and what factors might als...

Biofouling accumulation is not proactively managed on most marine static artificial structures (SAS) due to the lack of effective options presently available. We describe a series of laboratory and field trials that examine the efficacy of continuous bubble streams in maintaining SAS free of macroscopic biofouling and demonstrate that this treatmen...

Blood biochemistry and haematological parameters in fish are affected by environmental changes, nutritional status, stress and health. As such, they are useful indicators of fish health and welfare. However, the correct interpretation of these parameters depends on the availability of species-specific reference values. This study provides baseline...

Estuaries are the endpoints of rivers, which shape their physical and biological characteristics, yet few tools are available to link the health of estuaries to their upstream sources. As a first step towards the use of macro-invertebrate indices for setting ecological health thresholds in streams that also protect estuaries, we examined relationsh...

The success of biological control may depend on the control agent co-evolving with its target pest species, precluding the emergence of resistance that often undermines chemical control. However, recent evidence of a decline in attack rates of a sexual pest weevil by its asexual parasitoid suggests that evolutionary arms races may not prevent the e...

Model development, R code and information about parameters values. (PDF)

Results from the sensitivity analyses and figures illustrating the results from the “two species model” and the “three species model”. (PDF)

Sustainable and integrated pest management often involves insect parasitoids. However, the effectiveness of parasitoids biocontrol has often failed, frequently for obscure reasons. A parasitoid's success is partly due to its behavioral response to pest density, i.e. its consumer functional response. For many years in New Zealand, a braconid parasit...

On the Antarctic Peninsula, lichens are the most diverse botanical component of the terrestrial ecosystem. However, detailed information on the distribution of lichens on the Antarctic Peninsula region is scarce, and the data available exhibit significant heterogeneity in sampling frequency and effort. Satellite remote sensing, in particular the us...

Seabirds along the western Antarctic Peninsula are known to be shifting in abundance and distribution in response to changing sea ice and prey distributions, but the spatial extent of these changes has remained an open question because survey efforts have focused on the more easily accessed northern coastline. We used a yacht-based field expedition...

The Antarctic Peninsula (AP) is one of the most rapidly changing environments on the planet; mean annual air temperatures have increased by ~3 ºC in the last 50 years. This climatic change has led to longer summers and higher summer-growing season temperatures and, coupled with local glacial retreat, new bare-ground is exposed for colonisation by p...

Lack of field time, access to experts, and the challenges associated with research permits make traditional approaches for determining species richness (comprehensive collection and determination of biological specimens) impractical in many situations. To accelerate local biodiversity assessments for conservation and resource management, scientists...

This data set represents the accumulation of 19 years of seabird population abundance data collected by the Antarctic Site Inventory, an opportunistic vessel-based monitoring program surveying the Antarctic Peninsula and associated sub-Antarctic Islands. This Data Paper, which includes 1124 records from 113 locations for seven species of seabirds (...

Expert collection of specimens in the field and further determination of species is the best method for determining species richness. However, the relative paucity of botanists working in Antarctica makes this approach impractical for broad-scale surveys of Antarctic floral biodiversity. Lichens are the dominant macrophytes of terrestrial Antarctic...

Mosses and lichens are the dominant macrophytes of the Antarctic terrestrial ecosystem. Using occurrence data from existing databases and additional published records, we analyzed patterns of moss and lichen species diversity on the Antarctic Peninsula at both a regional scale (1°latitudinal bands) and a local scale (52 and 56 individual snow- and...

Background/Question/Methods Careful expert collection of specimens in the field and further determination of species is the most reliable method for determining species richness. However, either lack of access to experts or extended time lags between surveying and expert identifications may make this approach impractical, especially in remote are...

Background / Purpose: Deciding between growth and reproduction is fundamental in determining life history strategies. How many resources are allocated to somatic growth and/or reproduction is a developmental decision with consequences affecting a species' ecological context. We explored resource allocation strategies and their effects on population...

Background/Question/Methods Antarctic Peninsula biogeography is unique due to its extreme geographical isolation and pronounced latitudinal gradients. Mosses and lichens are the dominant macrophytes in the terrestrial Antarctic ecosystem, and research has highlighted the Peninsula’s vulnerability to accidental human-mediated introduction of both...

Utilizando modelos matriciales, analizamos cómo las características del sitio de nidificación, al determinar diferentes tipos de hormigueros, influyen sobre la demografía de la hormiga cortadora Acromyrmex lobicornis en el noroeste de la Patagonia. El incremento anual de nidos cuyos domos fueron construidos en la base de plantas fue el doble que pa...

We used matrix population models to explore how the characteristics of the nesting site, which determine different kind of ant-nest mounds, affect the population dynamics of the leaf-cutting ant Acromyrmex lobicornis in north-western Patagonia. The annual growth rate for ant-nests with mounds built at the base of plants was 100% higher than for the...