CCAMLR Science, Volume 21 (2014)
Conducting marine research in the Antarctic is expensive – ships are expensive to run and cost even more to replace. This has been highlighted in the media surrounding those national Antarctic programs currently in the process of procuring multidisciplinary research and logistics vessels. The paper by Godø and others is a slight departure from the ‘normal’ science paper in that it does not describe the results of a standard research project, but describes potential new ways to conduct research. Scientists and commercial companies working together to optimise the design of a fishing vessel so that it can conduct high-quality marine research is an exciting prospect. As a science community we are unlikely to have cheap options for doing marine research in the Antarctic, so perhaps the emphasis needs to be on a new way of using existing platforms, including fishing vessels, to better assist researchers. In a similar vein, the paper by Mugue et al. on the circumpolar genetics of toothfish would not have been possible without the data collected by scientific observers on board fishing vessels.
The two papers by Mormede and colleagues on the management of the Ross Sea toothfish fishery are a welcome addition to the body of scientific work in this region. So much work goes into the science underpinning CCAMLR’s management of this fishery and yet much of the detail remains somewhat hidden in the ‘grey’ literature and CCAMLR reports. I use the term ‘grey’ with trepidation as I think that it understates the actual level of ‘peer-review’ that many papers are exposed to in providing management advice to CCAMLR.
The relative anonymity of the peer-review process that most scientists are exposed to is quite different to the process of review when taking science into the management sphere. If an author submits a paper to a particular journal and the paper is declined, then there are likely to be a number of alternative journals to which the paper (hopefully revised in the light of the reasons for the decline) could be submitted. There are no such alternatives when submitting a paper that aims to change the way CCAMLR undertakes a particular aspect of its management; so the process can take a while. Getting an email from an editor with the reviewers’ comments on your paper can sometimes be hard. Having those reviewers in the room as you present your paper to an expert group can present quite a different challenge.
However, the same basic principle of good science underlies both of these review processes. The audiences are different and so the presentation of the results and conclusions has to be tailored to maximise the impact of the work. Developing appropriate metrics to measure impact, whether it is the impact factor of a journal or the impact on the management of marine resources, is a challenge, but it is a challenge that deserves to be addressed to ensure that the range of excellent science that is conducted in support of bodies like CCAMLR receives appropriate recognition by the academic community. Furthermore, ensuring that such science is appropriately recognised will, hopefully, encourage more of the global research community to re-examine how the impact of their science is defined and the ways in which it could have a real impact.
This study presents data on the DNA analysis of recent (2011–2013) samplings of Antarctic toothfish (Dissostichus mawsoni) from CCAMLR Subarea 48.5 (2013) and SSRUs 486G (2011), 5841E and 5841FG (2011), 5842E (2011), 881C (2011), 882A (2011, 2012) and 883C (2012). No significant genetic differences between geographic locations, or between samples collected in consecutive years, were observed. These results, based on analysis of the most informative subset of nuclear genetic markers of SNP variation presented in Kuhn and Gaffney (2008), do not support genetic differentiation of samples from the Ross Sea. Discrepancies in the allelic frequencies for several loci compared to previously published data highlight the need for further study of the genetics of Antarctic toothfish. |
The climate-induced changes presently seen in the ecosystems of the Antarctic region require a precautionary approach with respect to the human use of these ecosystems. In particular, resource harvesting requires enough basic knowledge, as well as adequate monitoring, to avoid unintended impacts on the harvested stocks and the associated ecosystem. Due to the vastness and remoteness of the Antarctic region, research vessel capacity is not readily available for conventional coverage of harvested stocks and their ecosystems. This paper describes the potential of using commercial fishing vessels to bridge the gap in research vessel capacity. The various tasks and required instrumentation are presented and discussed. To illustrate this concept a description of a Norwegian krill fishing vessel now under construction is presented. This type of combined fishing and research vessel could make a large amount of important data available for both management, through CCAMLR, and the broader scientific community and thus improve the basis for resource evaluation and management. |
Population modelling software was developed that captures the dynamics of spatial heterogeneity of the population along with age structure, movement and reproductive stage transition in a holistic framework. Using this software, three spatially explicit age-structured models were developed for the Antarctic toothfish (Dissostichus mawsoni) population in the Ross Sea region and used as operating models to evaluate the performance of single-area assessments. The models were generalised Bayesian population models and were optimised by fitting to fishery observations. Movement was parameterised using preference functions based on spatially discrete environmental layers. The shapes of the preference functions were established through iterative model testing whilst the parameters defining the preference functions were estimated within each model. The spatial structure of the models divided the Ross Sea region into 189 equal-area (24 000 km2) cells. The underlying spatial distribution of the population was either restricted to the 65 cells historically fished, to the 120 cells containing habitable depths, or to the entire Ross Sea region (all 189 cells). Estimates of movement rates were consistent with the results of tagging studies and fits to the other observations (age, reproductive development) were adequate. These operating models were then used to investigate potential biases of the current single-area stock assessment. Simulations based on the three spatial distribution scenarios suggested that the current single-area stock assessment is biased low by 19–43%. |
An exploratory longline fishery for Antarctic toothfish (Dissostichus mawsoni) has been carried out in the Ross Sea region since the late 1990s. No fishery-independent methods of monitoring stock abundance were plausible, and hence a multi-year mark-recapture tagging program was initiated by New Zealand fishing vessels in 2001, and tagging has been an ongoing requirement for all vessels fishing in the fishery since 2004. Although tagging experiments are commonly used for assessing fish stocks, most rely on estimates of abundance from a single release and subsequent recapture events. An integrated Bayesian stock assessment model was developed for Antarctic toothfish in the Ross Sea region that incorporates multi-year release of tagged fish and subsequent multi-year data of recapture of tagged fish in conjunction with fishery catch-at-age data. This is the first published stock assessment of toothfish in the Ross Sea region. It demonstrates the value of multi-year mark-recapture programs to estimate fish stocks even where no fishery-independent estimates of adult biomass are available. Monte-Carlo Markov Chain (MCMC) estimates of initial (equilibrium) spawning stock abundance (B0) were 68 790 tonnes (95% credible intervals 59 540–78 470), and current (B2013) biomass was estimated as 74.8% B0 (95% CIs 71–78). Sensitivity analyses carried out showed the data selection provided a precautionary estimate of biomass, and that these estimates were insensitive to selectivity assumptions regarding cryptic biomass of older fish. Results also suggested that a sub-adult survey series that started in 2012 will provide a useful signal indicative of recruitment fluctuations as the time series develops, a signal which is not present in the fishery-dependent data. |