Paul A. Hamer

The Pacific Community | SPC · Fisheries Aquaculture and Marine Ecosystems (Oceanic Fisheries Programme)

The general conclusions of this assessment are as follows: • The spawning potential of the stock has become more depleted across all model regions until around 2010, after which it has become more stable, or shown a slight increase. • Average fishing mortality rates for juvenile and adult age-classes have increased throughout the period of the ass...

Marine species often exhibit genetic discontinuities concordant with biogeographic boundaries, frequently occurring due to changes in ocean circulation, bathymetry, coastline topography, and temperature. Here, we used 10 916 single nucleotide polymorphisms (SNPs) to assess the concordance between population genomic differentiation and coastal bioge...

The structure, materials and designs of drifting Fish Aggregating Devices (dFADs) have generally remained rudimentary and relatively unchanged since they first came into use in the 1980 s. However, more recently, dFADs have been increasing in dimensions and the prevailing use of plastic components. Abandoned, lost or discarded dFADs can therefore c...

The tuna fisheries assessment report (commonly referred to as the "TFAR") provides current information on the tuna fisheries of the western and central Pacific Ocean and the fish stocks (mainly tuna) that are impacted by them. The information provided in this report is summary in nature, but a list of references (mostly accessible via the internet)...

This analysis presents additional work in order to constrain the model grid employed for the 2021 south Pacific blue shark(BSH) stock assessment in the Western and Central Pacific Ocean.

In the Western and Central Pacific Ocean (WCPO), programmes of large-scale tagging experiments have been carried out on skipjack, yellowfin and bigeye tuna, to aid estimation of movement and mortality parameters through the stock assessment model MULTIFAN-CL. The integration of tagging data in this context includes critical assumptions about the pe...

This paper describes the 2022 stock assessment of skipjack tuna Katsuwonus pelamis in the western and central Pacific Ocean.

Growth is a key uncertainty in the skipjack stock assessment for the Western and Central Pacific Fisheries Commission (WCPFC) convention area. Three new growth curves were produced as possible alternatives for use in the 2022 WCPFC skipjack assessment. For the 2022 diagnostic case, growth is estimated internally within MULTIFAN-CL, largely informed...

Achieving a sustainable socio-ecological future now requires large-scale environmental repair actioned across legislative borders. Yet, enabling large-scale conservation is complicated by policy-making processes that grapple with a disconnect between socio-economic interests and political priorities, multiple sources of knowledge, and differing app...

The tuna fisheries in the western and central Pacific Ocean (WCPO), encompassed by the Western and Central Pacific Fisheries Commission Convention Area (WCPFC-CA), are diverse, ranging from small-scale, artisanal operations in the coastal waters of Pacific states, to large-scale, industrial purse seine, pole-and-line and longline operations in the...

The value of critical habitats, such as seagrass, to act as a nursery varies spatially and temporally; however, such information is essential for the public and stakeholders to appropriately value and manage these habitats. We use an existing systematic long-term fisheries dataset in Port Phillip Bay to examine variability in nursery habitat value...

This paper describes the 2021 stock assessment of albacore tuna (Thunnus alalunga) across the South Pacific ocean (south of the equator), incorporating the Convention areas of the Western and Central Pacific Fisheries Commission (WCPFC) and the Inter American Tropical Tuna Commission (IATTC).

This paper describes the 2021 stock assessment of swordfish (Xiphias gladius) in the southwest Pacific Ocean (SWPO) using a sex-aggregated model structure in MULTIFAN-CL.

Drifting Fish Aggregating Devices (dFADs) are used in large numbers in the Western and Central Pacific Ocean (WCPO), and their potential impacts in a number of areas are of growing concern. This paper summarises the work from several dFAD-related projects, including: i) a regional database on beached and lost dFADs; ii) updated estimates on the num...

This report presents a study, in partnership with fishing companies, satellite buoy providers, and funded by The Nature Conservancy (TNC), to identify and evaluate options for reducing drifting Fish Aggregating Devices (dFADs) loss, thereby reducing associated ecosystem impacts. The study investigates the spatial and temporal dynamics of dFAD use a...

WCPFC Project 110 will conduct trials of non-entangling and biodegradable drifting Fish Aggregation Devices (dFADs) in the Western and Central Pacific Ocean (WCPO). It will provide essential information to the tuna fishing industry on the designs, types of materials, performance and cost-effectiveness of non-entangling and biodegradable dFADs in th...

Drifting Fish Aggregating Devices (dFADs) are a major fishing mode for tropical tuna purse seine fisheries worldwide. However, the extent of dFAD use remains poorly understood. We present novel approaches for estimating annual dFAD deployments and number of dFADs monitored by individual vessels, using empirical data and robust estimation procedures...

Spawning sources of King George whiting Sillaginodes punctatus populations in the states of South Australia and Victoria (south-eastern Australia) were analysed using otolith chemistry and microstructure from post-larvae sampled from 3 nursery areas in each state in the spring of 2011 and 2012. Univariate and multivariate analysis of the chemistry...

This report focuses on the primary tuna stocks targeted by the main WCPO industrial fisheries - skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), bigeye (T. obesus) and South Pacific albacore tuna (T. alalunga). The report is divided into three parts: the first section provides an overview of the fishery, with emphasis on developments...

Victorian wrasse populations support mostly local port-based commercial fisheries. The Victorian fishery predominantly uses ‘hook & line’ to harvest wrasse from in-shore waters (<30m depth) year-round for the live fish restaurant market. There is also a small recreational fishery. This document summarises the performance of the Victorian ocean wras...

The assessment of yellowfin tuna Thunnus albacares from the western and central Pacific Ocean (WCPO) relies heavily on fishery-dependent data to inform the assessment model on trends in biomass. The longline fishery, which primarily targets adult yellowfin provides key inputs to the assessment; however these data may be unreliable when it comes to...

Developing a reliable index of relative abundance for skipjack, to inform the assessment model on trends through time, is a priority given the contraction of the pole-and-line fishery. Catch rates from the pole-and-line fishery have been a key input into the skipjack assessment models in the past, but the fishery’s ability to provide the spatial an...

This paper describes the 2020 stock assessment of bigeye tuna (Thunnus obesus) in the western and central Pacific Ocean.

Planned adaptation to climate impacts and subsequent vulnerabilities will necessarily interact with autonomous responses enabled within existing fisheries management processes and initiated by the harvest and post-harvest components of fishing industries. Optimal adaptation options are those which enable negative effects to be mitigated and opportu...

ISBN 978-1-76090-121-9 (Print) ISBN 978-1-76090-126-4 (pdf/online/MS word)

We review the status of marine shellfish ecosystems formed primarily by bivalves in Australia, including: identifying ecosystem-forming species, assessing their historical and current extent, causes for decline and past and present management. Fourteen species of bivalves were identified as developing complex, three-dimensional reef or bed ecosyste...

Published research articles and reports on Australian shellfish ecosystem-forming species. See Table 2 for category codes. (DOCX)

We conducted a before-after-control-impact (BACI) experiment to evaluate the effects of deploying small-scale artificial patch reefs on fish assemblages in a temperate bay (Port Phillip Bay) in south-eastern Australia. Three replicate artificial reef treatments were placed on sandy substratum and the response of the fish assemblage was compared wit...

The Port Phillip Bay snapper fishery is highly valued by anglers, and is a major drawcard for recreational fishing in Victoria. The adult fishery is highly seasonal depending on migration of fish to and from the bay and coastal waters, and their aggregation in certain regions of the bay for spawning in spring-summer. The bay is also a juvenile nurs...

Snapper, Chrysophrys auratus, is a highly important fishery resource of southern Australia. Through the late 2000s, the State of South Australia (SA) produced record commercial catches of this species, making the dominant contribution to the national catch. This was associated with dramatic changes in contributions from SA’s regional fisheries. The...

Executive Summary What the project achieved The first spatial mapping of Blue-eye Trevalla stocks in Australian waters was completed between 2013 and 2016 using a variety of techniques, novel approaches, leading edge technology, a synthesis of historical data, and input from knowledgeable commercial fishers. Each of our three primary analyses pr...

Fisheries Victoria conducts periodic assessments of the status of key fish species and the fisheries they support. These assessments compile relevant data from recreational fishery monitoring programs, commercial fishery catch and effort reporting where available, scientific surveys and other data such as age and length composition, to support a ‘w...

Survival of larval fish is often linked to production of preferred prey such as copepods, both inter- and intra-annually. In turn, copepod production depends not only the quantity of food, but also on the nutritional quality, edibility and/or toxicity of their micro-algal food. Hence, larval fish survival can become de-coupled from levels of nutrie...

Fisheries Victoria conducts periodic assessments of the status of key fish species and the fisheries they support. The assessments compile relevant data from commercial fishery catch and effort reporting, recreational fishery monitoring programs, scientific surveys (such as juvenile pre-recruit surveys) and other data, such as age and length compos...

Overview This was a collaborative project amongst scientists from the University of Melbourne, Fisheries Victoria, Deakin University and the South Australian Research and Development Institute. The project led to major advances in our understanding of the biology and population structure of King George Whiting in southern Australia. The project wa...

Victoria has lost vast areas (>95%) of native flat oyster (Ostrea angasi, Sowerby 1871) and blue mussel (Mytilus edulis galloprovinicialis, Lamarck 1819) reefs from estuarine and coastal waters since European settlement. We document the decline of these reefs by examining indigenous use of shellfish, the decimation of oyster reefs by dredge fishing...

While arrow squid (Nototodarus gouldi) in Australia are currently managed as a single population, biological differences in individuals between locations of capture suggests these are separate stocks requiring stock-specific harvest strategies. We used two techniques to derive information about stock structure from different parts of the life cycle...

Australians have a profound love for coastal and marine environments. Whilst iconic destinations such as the Great Barrier Reef, The Twelve Apostles and Rottnest Island annually attract millions of international visitors, Australians on weekends and over the summer holidays flock towards lesser-known, family destinations such as Lakes Entrance, Nam...

Variation in strontium (Sr) and barium (Ba) within otoliths is invaluable to studies of fish diadromy. Typically, otolith Sr:Ca is positively related to salinity, and the ratios of Ba and Sr to calcium (Ca) vary in opposite directions in relation to salinity. In this study of jungle perch, Kuhlia rupestris, otolith Sr : Ca and Ba : Ca, however, sho...

In fishes, the growth-mortality hypothesis has received broad acceptance as a driver of recruitment variability, with food-limitation and selective mortality resulting in the removal of slow-growing, small individuals from the population. Based on long-term monitoring in Port Phillip Bay, Australia, pink snapper, Chrysophrys auratus (Sparidae), exp...

In fishes, the growth-mortality hypothesis has received broad acceptance as a driver of recruitment variability. Recruitment is likely to be lower in years when the risk of starvation and predation in the larval stage is greater, leading to higher mortality. Juvenile snapper, Pagrus auratus (Sparidae), experience high recruitment variation in Port...

In 2006 the State Government of Victoria committed to conducting a trial of artificial (man-made) reefs to test their performance as a recreational fishery enhancement tool in Port Phillip Bay, and provide an assessment of their potential fishery management and broader ecological implications. The objectives of the trial were to: 1. Assess the im...

There is a growing awareness of the impacts of fisheries on the marine ecosystem and the need for ecosystem-based fisheries management. Fisheries, particularly export fisheries, are increasingly being required to show that they are ecologically sustainable. A prime objective of the current management plan for the Victorian abalone fishery is to for...

Fish have complex life cycles that contribute to interannual variability in recruitment. The growth-mortality hypothesis has received broad acceptance as a driver of recruitment variability, with cohorts comprised of fast-growing large-at-age larvae having high larval survival and subsequent juvenile recruitment. Long-term monitoring in Port Philli...

The European sardine is one of the most important clupeoid fish captured by the Portuguese and Spanish purse-seine fleets in the Atlantic waters of the Iberian Peninsula. Despite the importance of this species, and substantial decrease in catches over the last two decades, knowledge about sardine movements and connectivity between their juvenile re...

Climate change has already been linked to significant impacts on Earth's ocean ecosystems including shifts in species geographic ranges, changes in population abundance, shits in timing of seasonal events, and establishment of introduced species (Walter et al. 2002, Parmesan and Yohe 2003). Global climate modelling for the Australian region has ide...

Arrow squid, Nototodarus gouldi, are managed as a single population in Australia; however, it is unknown whether N. gouldi caught in Victoria and the Great Australian Bight are from separate stocks. This study examines whether N. gouldi caught in these two spatially separated locations of southern Australia are different stocks. Fourier shape analy...