Home PROJECTS Climate Change Ocean acidification impacts
Ocean acidification impacts
Impacts on tropical tuna
Friday, 18 February 2011 15:09

The unaccounted impacts of ocean acidification (and warming) upon tuna stocks in the Pacific (and globally) represent a serious risk to the achievement of sustainability based management objectives for both Regional Fisheries Management Organisations (RFMOS) and for the policies of sovereign states responsible for tuna fisheries management in the Pacific region.  Research has demonstrated that the early life history stages of some fish species (and numerous other marine organisms) are sensitive to ocean acidification levels that are projected to occur by the end of this century. Those findings have significant implications for future recruitment success and population levels for those species. Utilising the long established expertise and unique facilities at the IATTC’s Achotines Laboratory in Panama, the first year of this project aims to elucidate the impacts of projected ocean acidification levels upon processes and life history stages of yellowfin tuna (Thunnus albacores) that are considered critical to recruitment success: sperm motility, fertilisation rates, embryonic development, hatching rates, condition, development, growth and survival in pre- and post-feeding larvae.  Empirical results from the laboratory trials will then be used, in conjunction with physical oceanographic data from ocean acidification projection models, to parameterise the SEAPODYM model and evaluate the impact of ocean acidification upon the distribution and abundance of yellowfin tuna in the Pacific Ocean. The outputs from this project will reduce uncertainty regarding future stock trends as provided to tuna RFMOs in the Pacific, increasing the likelihood that these organisations can make decisions that ultimately achieve sustainability based management objectives.

Read the full document icon PFRP Proposal - Ocean acidification impacts upon tropical tuna populations (1.75 MB)

 
Background
Friday, 18 February 2011 15:13

The Pacific tuna fisheries are among the largest, most complex and valuable fisheries resources in the world.  In 2008, the most recent year with confirmed statistics, the total tuna catch exceeded 3 million tonnes (Williams and Terawasi, 2009; IATTC, 2009), comprised 70% of the total global tuna catch and was valued at USD 4.8 billion dollars. The Western and Central Pacific Fisheries Commission (WCPFC), the Inter-American Tropical Tuna Commission (IATTC) and the Western Pacific Regional Fisheries Management Council (WPFMC) are responsible for ensuring the sustainable use of this globally significant resource.

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Objectives
Friday, 18 February 2011 15:50

The objectives of this project are three-fold:

  • Firstly, to collect and collate the experimental data necessary to evaluate the potential impacts of altered gamete, fertilisation, embryonic development, hatching and larvae ecology from projected increases in ocean acidity in the Pacific Ocean for yellowfin tuna.
  • Secondly, to utilize the experimental data to parameterise the SEAPODYM model to evaluate the impact of projected ocean acidification (and warming) upon the distribution and abundance of yellowfin tuna.
  • Thirdly, provide information on the potential impacts of ocean acidification upon tuna stocks, in particular yellowfin tuna, to RFMOs for consideration in management decision making processes.
 
Timing
Friday, 18 February 2011 15:56

This is a two year project, with laboratory based work to be completed in the first year (2011) and SEAPODYM modeling component to be completed in the second year (2012)

 
Expected outcomes
Friday, 18 February 2011 15:55

The research plan is based around a two-year time line. The expected outcome at the end of two years is a model (SEAPODYM) based evaluation of the expected impact of ocean acidification upon the distribution and abundance of yellowfin tuna in the Pacific Ocean. The results from this modeling will be written up and reported to the Scientific Committees (or equivalent) of the WCPFC, IATTC and WPFMC. This information will enhance the capacity of these RFMOs to make more informed decisions regarding the management of the tuna resources, particularly with regard to attaining key sustainability related objectives.

 
Methodology
Friday, 18 February 2011 15:52

Laboratory trials

The effects of ocean water acidification upon yellowfin tuna early life history processes and stages will be tested experimentally at the Achotines Laboratory in four phases:

  • Sperm and Fertilization trials
  • Egg/embryonic development trial
  • Yolk-sac larval stage trial
  • Early feeding larval stage trial  

Data analysis

Data collected from the laboratory trials will be analyzed using generalized linear models (GLMs) with the statistical software R

SEAPODYM modeling

Physical and biogeochemical conditions influence tuna population dynamics through changes in spawning conditions, habitat suitability, and distributions of food resources that result in changes in fish movement behavior, reproduction and mortality. Environmental data are used in SEAPODYM to functionally characterize the habitat of the population depending on its thermal biogeochemical and forage preferences (Lehodey et al. 2008).

 


 
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