Natalie Dowling

CSIRO Marine And Atmospheric Research

By March 2020 coronavirus disease 2019 (COVID-19) was anticipated to present a major challenge to the work undertaken by scientists. This pandemic could be considered just one of the shocks that human society has had and will be likely to confront again in the future. As strategic thinking about the future can assist performance and planning of sci...

Recreational fishing (RF) is a large yet undervalued component of fisheries globally. While progress has been made in monitoring, assessing, and managing the sector in isolation, integration of RF into the management of multi‐sector fisheries has been limited, particularly relative to the commercial sector. This marginalises recreational fishers an...

Marine ecosystem-based management often aims to satisfy a wide range of economic, social and environmental objectives. These are often measured in non-commensurable units, making identification of a preferred option difficult when outcomes and measures vary considerably. In this paper, we examine the potential for data envelopment analysis (DEA) as...

The term “data-limited fisheries” is a catch-all to generally describe situations lacking data to support a fully integrated stock assessment model. Data conditions range from data-void fisheries to those that reliably produce quantitative assessments. However, successful fishery assessment can also be limited by resources (e.g., time, money, capac...

Successful fisheries management systems tend to be underpinned by harvest strategies, specifying formally agreed data collection systems, assessment approaches and management measures used to regulate fishing pressure. While harvest strategies can be effective even in data‐ and capacity‐limited (DCL) situations, their development remains challengin...

Marine population modeling, which underpins the scientific advice to support fisheries interventions, is an active research field with recent advancements to address modern challenges (e.g., climate change) and enduring issues (e.g., data limitations). Based on discussions during the ‘Land of Plenty’ session at the 2021 World Fisheries Congress, we...

Recreational fishing (RF) is a popular pastime resulting in substantial fish mortality in many regions. Yet inclusion of RF in fishery harvest strategies is limited, because the sector's objectives are poorly understood, as are the data required to track their performance. To address this, we reviewed RF data sources available from a region of glob...

As the world population grows, fisheries practitioners will be under increased pressure to address global challenges in data-limited fisheries management. With a focus on addressing localized and case-specific management needs, we provide a practical guide to the design and development of multi-indicator frameworks for fishery management. In a data...

Stock assessments are integral to fisheries management, and the demand for stock assessments based on population dynamics models continues to increase. Historically, stock assessments have been based on bespoke methods and software. There is now a trend towards the use of flexible, documented, tested and maintained software packages, because use of...

Natural resource management has long recognised that the multi-objective nature of management is important, but has struggled to operationalise this into quantitative, measurable objectives for functional use in management. Operationalising broader ecological and social objectives has been particularly problematic. In fisheries management, the focu...

Fisheries are increasingly managed with involvement of fishers and other stakeholders; this approach is believed to create ownership and maximize stakeholder buy-in. Stakeholder involvement is critical where managers lack adequate knowledge, resources to gather additional information, or resources to implement management. Such ‘data-limited’ fisher...

Over the past 50 years, the diversity of fisheries types being actively managed has changed from mainly data-rich, industrial sectors to more socially, economically, and environmentally complex multispecies and multisector fisheries. Accompanying this change has been a broadening of management objectives to include social and economic consideration...

Ecosystem based fisheries management (EBFM) provides a framework to achieve ecological, economic and social sustainability in fisheries. However, developing harvest strategies to achieve these multiple objectives is complex. This is even more so in multi-sector multi-species fisheries. In our study, we develop such harvest strategies for the multi-...

Among abalone species that were once harvested along the California coastline, red abalone (Haliotis rufescens) supports the remaining recreational fishery. To support development of a red abalone fishery management plan, non‐governmental organizations have initiated expanded data collection and developed fishery management strategies. The latter i...

The majority of the world's fisheries, by number, are data‐poor/limited, and there is a growing body of literature pertaining to approaches to estimate data‐limited stock status. There are at least two drivers for assessing the status of data‐limited fisheries. The first is to try to understand and report on the global or regional status of fisheri...

We proposed two hypotheses to explain why food chains are longer in pelagic than terrestrial ecosystems: greater trophic efficiency of pelagic animal taxa at lower trophic levels and a higher pelagic biomass production rate at lower trophic levels because of smaller pelagic body masses. Giacomini favored the former, invoking in support the energeti...

In response to a vessel buyback scheme in a major Australian Commonwealth fishery, nominal catch-per-unit-effort (CPUE) showed dramatic increases. These led to a discontinuity in the statistically standardised CPUE time series, which may also suggest a discontinuity in the relationship between catch-per-unit-effort and abundance. We hypothesise the...

Harvest strategies (HSs) have been applied to many data-rich fisheries, and are now increasingly being applied in data-limited situations. These have been evaluated using simulation frameworks, including management strategy evaluation (MSE), but few studies have considered the full spectrum from data-rich to data-limited strategies, in the context...

(P.T. Perikanan Samodra Besar) data are a valuable source, since they are the longest time series of catch and effort data available from the fishery. This paper aimed to interpret the spatial and temporal catch and effort trends to the extent possible and to reconcile apparent changes in targeting practices against the actual catch. Catch and effo...

We propose a conceptual framework for evaluating fishery management performance using conservation, economic, and sociocultural metrics. We develop a value function that weights outcomes for each measure based on their relative importance to decision makers and show how it can be derived from fundamental economic principles (the latter initially in...

Several fisheries jurisdictions are aiming to achieve risk equivalency (here defined as the probability of a stock being depleted below a limit reference point or not being maintained at a target reference point) irrespective of the stock assessment method used to provide management advice and the amount of data available. Risk equivalency is impli...

Tier systems for fisheries assessment and management are widely used, but defined differently by jurisdiction. A principal component analysis was applied to the expanded Australian Commonwealth 8-tier system for fishery assessment and management to determine whether it adequately delineates across stocks according to data availability and quality....

Factors constraining the structure of food webs can be investigated by comparing classes of ecosystems. We find that pelagic ecosystems, those based on one-celled primary producers, have longer food chains than terrestrial ecosystems. Yet pelagic ecosystems have lower primary productivity, contrary to the hypothesis that greater energy flows permit...

One of the endeavours to address the shortage of catch per unit effort (CPUE) information from the Indonesian Indian Ocean tuna fishery is the collation of a large amount of catch and effort data collected by Indonesian Fisheries High School students (“FHS data”). This paper attempts to investigate spatial-temporal patterns of catch and effort of t...

There can be substantial differences in data quality and quantity among fished species. Consequently, the quality and type of assessments can also vary substantially. However, all species, especially those that are targeted, need to be managed. Several jurisdictions have developed hierarchical tier systems that categorize stocks based on, for examp...

Fisheries management operates in an environment characterized by multiple risks. These risks are often complementary and can be traded off against each other. An important goal for managers is to develop strategies to minimize the overall risk exposure at minimal cost. We show a simple model that quantifies a range of risks faced by fisheries manag...

In an effort to address a shortage of reliable CPUE information, and as a preliminary step to a broader observer program, Indonesia established a Trial Observer Program (TOP) for the industrial tuna long line fishery based at Benoa Fishing Port, Bali, in mid 2005. The objectives of this paper are i) to describe spatial and temporal catch and effort...

http://frdc.com.au/research/Documents/Final_reports/2010-044-DLD.pdf The implementation of the Commonwealth Harvest Strategy Policy requires limit and target reference points for each fishery. These reference points can be both biomass-based (e.g., BTARG, BMSY, BLIM etc.) and fishing mortality-based (e.g., FTARG, FMSY, FLIM etc.). Estimating these...

Risk sensitivity is an important component of fisher behaviour, yet its impact on fisher decision-making and utility is poorly understood. Here, we incorporate various forms of risk in a model of location choice by fishing vessels targeting broadbill swordfish, Xiphias gladius, and evaluate the importance of risk sensitivity for predicting location...

Bycatch of threatened, endangered or protected species by commercial fishers is a universal problem. Technical solutions are often applied that may impose inefficiencies across the fleet, even in periods or areas when the risk of bycatch is low. These may include gear specifically designed to avoid the bycatch which may also reduce the targeted cat...

Sustainable fisheries management into the future will require both understanding of and adaptation to climate change. A risk management approach is appropriate due to uncertainty in climate projections and the responses of target species. Management strategy evaluation (MSE) can underpin and support effective risk management. Climate change impacts...

Colin Clark made seminal contributions in both resource economics and behavioral ecology. In the former, he showed how to link biological and economic factors in a consistent mathematical framework, virtually creating the field of mathematical bioeconomics single-handedly. In the latter, he was a major contributor of the introduction of state varia...

Abundance indices based on nominal CPUE do not take into account confounding factors such as fishing strategy and environmental conditions, that can decouple any underlying abundance signal in the catch rate. As such, the assumption that CPUE is proportional to abundance is frequently violated. CPUE standardisation is one of the common analyses app...

Increasing use of spatial management tools in fisheries requires an understanding of fleet response, and in particular to where displaced fishing effort is likely to move. We develop a state-dependent decision-making model to address the spatial allocation of effort in an Australian tuna longline fishery. We assume that fishers have an economic obj...

In the domain of decision-support tools for the management of marine fish resources, considerable attention has been paid to the development of models explaining how fish stocks change over space and time. In most models, fishing effort is assumed to be exogenous and determined by factors such as management. Increasingly, there has been a call for...

Prince, J. D., Dowling, N. A., Davies, C. R., Campbell, R. A., and Kolody, D. S. 2011. A simple cost-effective and scale-less empirical approach to harvest strategies. – ICES Journal of Marine Science, 68: 947–960. An empirical harvest strategy for an Australian longline fishery was developed and tested using harvest strategy evaluation. The approa...

Although active targeting of abalone aggregations is documented for various species, its impact on large aggregations is poorly understood. As large aggregations make the greatest contribution to reproductive success, yet are vulnerable to exploitation, it is important to understand how targeted fishing impacts aggregation structure. If observed po...

The greenlip abalone (Haliotis laevigata) population in Waterloo Bay, South Australia, has undergone collapse and fishery closure twice since 1978. A rich data set, including survey measures of degree of spatial aggregation, has been gathered over that time and provides a unique opportunity to identify factors accounting for persistence or collapse...

Non-technical Summary This report describes a Management Strategy Evaluation (MSE) for the Australian Eastern Tuna and Billfish Fishery (ETBF), including: i) the development of single species operating models to represent each of the five target species, ii) the results from the simulation testing of a range of Harvest Strategies (HSs) for each tar...

The Eastern tuna and billfish fishery (ETBF) is currently managed through an input quota system based on individual transferable effort units (the number of hooks) and a total allowable effort level (i.e. total number of hooks) A spatial management policy based on a series of differential hook-penalties has been proposed as a flexible tool to disco...

Fisheries management is increasingly involving a wide range of stakeholders in the decision making process. However, in most fisheries, the set of management objectives are poorly defined, and the implicit importance placed on these objectives may vary considerably both between and within different stakeholder groups. This may lead to conflicts wit...

There is an increasing expectation for decision makers to use robust scientific advice on the status of exploited fish stocks. For example, Australia has recently implemented a harvest strategy policy for federally managed fisheries based on limit and target biomass reference points. In common with most fisheries jurisdictions, however, Australia h...

Australia has developed a Harvest Strategy Policy (HSP) for Commonwealth fisheries. A harvest strategy specifies the management actions necessary to achieve defined resource objectives in a given fishery, resulting in a formal and proactive management approach that is transparent to all stakeholders. The objectives of the HSP are defined in terms o...

Contrary to expectations there was no transition from a saltatory to a cruise search strategy in foraging behaviour of 7-to 33-day-old barramundi over the period of metamorphosis. Rather, there was a continual change in foraging behaviour, with increasing durations between swimming pauses and increasingly straight swimming paths, implying that hydr...

Further to the work done by Okamoto and Miyabe (1999) and Anon. (2001), we present several alternative methods for calculating annual abundance indices (or more correctly, indices of availability) for bigeye tuna in the Indian Ocean. The data file JPNLLCE.xls, provided by the IOTC and containing Japanese longline catch-effort data aggregated on a m...

Information on the size distribution, for example mean length, in the catch can potentially be used as an indicator of swordfish stock status. This study looked at the standardisation of such indices particularly for spatial and seasonal effects. Standardization of size-based indices smoothed temporal trends that were evident in the nominal data, l...

Document WPTT-01-13 presents a large number of analyses that summarize various aspects of the Japanese longline catch-and-effort data in the Indian Ocean since 1952. In particular, the analyses highlight the large spatial and temporal changes in the fishery over time and which need to be accounted for in stock assessments. The document shows that t...