Lauren M. Fletcher

• PhD
• Marine ecologist at Cawthron Institute

Sea-based fish farms are associated with strong benthic enrichment gradients and routine monitoring is usually required by regulation. Internationally a wide range of approaches exist for measuring the degree of benthic deterioration around fish farming activities, ranging from simple visual or odour assessments to the calculation of secondary indi...

The number and distribution of non-indigenous species in coastal habitats is increasing. Our ability to prioritise the management of this threat is limited by our understanding of their impacts. We investigated the density dependent effects of the non-indigenous solitary ascidian Pyura doppelgangera on native mussels and rocky shore communities in...

Unwanted biofouling and predatory pests are a universal problem threatening aquaculture productivity and profitability. Various control approaches have been trialled, but industry uptake has been elusive due to the typically fine balance between pest and bivalve physiological tolerances (i.e., ‘therapeutic window’) and operational challenges relate...

The global proliferation of marine artificial habitats is rapidly altering the physical structure of coastlines, with knock-on effects on physical, chemical, and ecological processes at seascape scales. Ecological consequences of maritime sprawl associated with aquaculture are poorly understood, despite the fact that these suspended structures are...

Vessel movements are considered the main anthropogenic pathway for secondary spread of marine non-indigenous species. Recent studies have highlighted the potential for viable organisms to be transported within bilge water of small vessels. In this study, a survey was conducted to (1) describe the bilge water operational profiles of a range of domes...

Impacts of pre-sampling practices on fish plasma biochemistry may bias the outcome of a study if not considered within the general sampling strategy. Acute handling stresses can be imposed on fish during capture, and it is common practice to immobilise fish via sedation prior to obtaining blood samples for non-lethal extraction purposes, and/or to...

Impacts of pre-sampling practices on fish plasma biochemistry may bias the outcome of a study if not considered within the general sampling strategy. Acute handling stresses can be imposed on fish during capture, and it is common practice to immobilise fish via sedation prior to obtaining blood samples for non-lethal extraction purposes, and/or to...

The colonial ascidian Didemnum vexillum is a high-profile marine invader, with a geographically widespread distribution after introductions to several temperate regions. D. vexillum has been the focus of several eradication and control programmes globally and the need for specific biological knowledge that relates to establishment processes, persis...

High-throughput sequencing metabarcoding studies in marine biosecurity have largely focused on targeting environmental DNA (eDNA). DNA can persist extracellularly in the environment, making discrimination of living organisms difficult. In this study, bilge water samples (i.e., water accumulating on-board a vessel during transit) were collected from...

Zip file containing quality filtered sequence data (concatenated fasta file), as well as the Operational Taxonomic Units (OTUs) table and corresponding taxonomic table obtained from the bioinformatics pipeline. (ZIP)

Rarefaction curves of eukaryotic 18S rRNA sequences collected from the combined bilge water triplicate subsamples from vessels in the Nelson and Picton marinas between January to March 2015, with (A) DNA, and (B) RNA. (TIFF)

List of the 1,437 Operational Taxonomic Units (OTUs) retained for downstream analyses, with their assignment at the lowest possible taxonomic level and the number of corresponding sequences recovered for each OTU within the 15 eDNA and 15 eRNA samples investigated. Note: Some invasive species listed (e.g., Septifer biolcularis, Mytilus trossulus) h...

Relative abundance of selected taxa (genus level) contributing >10% to pairwise difference in relative abundance of sequences in the DNA and RNA samples (based on SIMPER analysis results). See Table 1 for sample information. (PNG)

Vessel movements are considered the primary anthropogenic pathway for the secondary spread of marine non-indigenous species. In comparison to the well-studied mechanisms of hull fouling and ballast water, the importance of bilge water for domestic and cross-regional spread of non-indigenous species is largely unknown and has the potential to compro...

Biofouling is a significant operational problem for the aquaculture industry globally; however, options for on-farm management are limited. In New Zealand, the green-lipped mussel, Perna canaliculus, has historically been cultivated at inshore locations, but increased competition for space has led the industry to develop offshore farming sites seve...

Encapsulation of fouled structures is an effective tool for countering incursions by non-indigenous biofoulers. However, guidelines for the implementation of encapsulation treatments are yet to be established. This study evaluated the effects of temperature, biomass, community composition, treatment duration and the biocide acetic acid on biofouler...

The desiccation tolerance of biofouling taxa (adults and early life-stages) was determined under both controlled and ‘realistic’ field conditions. Adults of the ascidian Ciona spp. died within 24 h. Mortality in the adult blue mussel Mytilus galloprovincialis occurred within 11 d under controlled conditions, compared with 7 d when held outside. The...

The occurrence of problematic pest organisms is an increasing global phenomenon, adversely affecting a range of environments and associated values. In marine systems, the efficacy of pest control has to date been constrained by a lack of tools that are not only highly effective, but also applicable across broad spatial scales. Here we consider the...

Non-indigenous species can dominate fouling assemblages on artificial structures in marine environments; however, the extent to which infected structures act as reservoirs for subsequent spread to natural habitats is poorly understood. Didemnum vexillum is one of few colonial ascidian species that is widely reported to be highly invasive in natural...

Biofouling can pose a significant threat to shellfish aquaculture, as fouling organisms are often strong spatial competitors that are able to reach high densities or biomass in relatively short time frames. This study investigated the potential impacts of the colonial ascidian Didemnum vexillum on cultured New Zealand green-lipped mussels Perna can...

The global spread of invasive fouling species poses a significant barrier to the development of shellfish aquaculture, which has led to a need to understand the biological characteristics of fouling species that underpin management. One such fouling species, the colonial ascidian Didemnum vexillum, has become a very successful invader in temperate...

Over the past decade, several species of non-indigenous ascidians have had adverse effects on a range of coastal ecosystems, and associated industries like aquaculture. One such species, the colonial ascidian Didemnum vexillum, poses a threat to the highly-valued New Zealand green-lipped mussel industry, and there is interest in whether and to what...

The colonial ascidian Didemnum vexillum has become relatively widespread in New Zealand, since its initial discovery in 2001. Despite the potential economic and ecological impacts of D. vexillum, there are still considerable knowledge gaps surrounding its key biological attributes. The ability to obtain larvae and culture colonies in the laboratory...