State of fish stocks

  • Image, State fish stocks.

    Our fish stocks are affected by commercial, customary, and recreational fishing, and changes in environmental pressures (eg ocean temperature, acidity, and productivity). The Ministry for Primary Industries uses three performance measures to assess fish stocks: a soft biomass limit (below which a stock rebuilding plan is required), a hard biomass limit (below which closing a fishery should be considered), and an overfishing threshold (above which the rate of extraction exceeds the optimal extraction rate).

    We classified State of fish stocks as a case study.

    Key findings

    The proportion of fish stocks in our exclusive economic zone subject to overfishing decreased from 25 percent in 2009 to 15 percent in 2015.

    • Of the fish landings (tonnage of fish brought back to shore) assessed up to 2015:
      • 96.8 percent were from stocks above the soft limit
      • 99.6 percent were from stocks above the hard limit
      • 94.6 percent were from stocks that were not subject to overfishing.
    • Of the fish stocks assessed against fisheries performance measures up to 2015:
      • 82.8 percent were above the soft limit
      • 94.0 percent were above the hard limit
      • 85.1 percent were not subject to overfishing.
    • At 2015, 17.2 percent of our fish stocks were overfished (below the soft limit) compared with 28.8 percent worldwide.

    Figure 1

    Note: A single stock with high landings can strongly influence results based on landings data. Results based on stock data can be overly influenced by the large number of small stocks, which often receive relatively little research effort. The soft limit is the limit below which a rebuilding plan is required.

    Figure 2

    Note: A single stock with high landings can strongly influence results based on landings data. Results based on stock data can be overly influenced by the large number of small stocks, which often receive relatively little research effort. The hard limit is the limit below which closure of a fishery should be considered.

    Figure 3

    Note: A single stock with high landings can strongly influence results based on landings data. Results based on stock data can be overly influenced by the large number of small stocks, which often receive relatively little research effort. The overfishing threshold is the extraction rate above which the stock may drop below management targets or limits.

    Definition and methodology

    We know the status of only some quota management system (QMS) stocks. There are 636 fish stocks in the QMS – 292 of which are considered nominal (trivial or unlikely to occur in a particular location). Of 344 non-trivial stocks for New Zealand fisheries, we know the status in 2015 of:

    • 157 relating to the soft limit (an increase of 65 percent since 2009)
    • 183 relating to the hard limit (an increase of 39 percent since 2009)
    • 121 relating to the overfishing threshold (an increase of 59 percent since 2009).

    These stocks represent most of the main commercial fish species: in 2015, stocks of known status relative to the soft limit accounted for 78 percent of the total landings by weight and value, representing most of the main commercial fish species (Ministry for Primary Industries, 2016).

    Models for assessing fish stocks include data on any significant customary or recreational catch. These data are taken into account in assessing stock status against the performance measures for soft limit, hard limit, and overfishing thresholds (Ministry of Fisheries, 2008).

    This measure covers the New Zealand exclusive economic zone and territorial sea.

    The New Zealand estimate of the proportion of overfished stocks is a composite of several years because not all stocks are assessed every year. The 2015 estimate includes results from previous years. The worldwide proportion of overfished stocks is derived from Food and Agriculture Organization of the United Nations (FAO) State of World Fisheries and Aquaculture (SOFIA) data (Food and Agriculture Organization of the United Nations, 2014). The FAO assessment is from 2011.

    The commercial fishing year for most fish stocks goes from 1 October to 30 September, but some fish stocks have a fishing year of 1 April to 31 March.

    Data quality

    Topic  Classification Relevance Accuracy
    Marine species, taonga species, and genetic diversity  Case study

     relevance-partial
    Partial

     accuracy-high
    High

    See Data quality information for more detail.

    References

    Food and Agriculture Organization of the United Nations (2014). The state of world fisheries and aquaculture. FAO State of World Fisheries and Aquaculture (SOFIA) series. Retrieved from www.fao.org.

    Ministry of Fisheries (2008). Harvest strategy standard for New Zealand fisheries. Retrieved from http://fs.fish.govt.nz.

    Ministry for Primary Industries (2016). The status of New Zealand’s fisheries 2015. Retrieved from http://fs.fish.govt.nz/.

    Archived pages

    See State of fish stocks (archived October 2016).

    Updated 27 October 2016

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