Qualitative (Level 1) risk assessment of the impact of commercial fishing on New Zealand chondrichthyans: an update for 2017 New Zealand Aquatic Environment and Biodiversity Report No. 201

Ford R, Francis M, Holland L, et al (2018) Qualitative (Level 1) risk assessment of the impact of commercial fishing on New Zealand chondrichthyans: an update for 2017 New Zealand Aquatic Environment and Biodiversity Report No. 201

New Zealand adopted a revised National Plan of Action for the Conservation and Management of Sharks (NPOA-Sharks 2013) in January 2014. Amongst other objectives, the NPOA-Sharks established a risk-based approach to prioritising management actions. An initial qualitative (level 1) risk assessment (RA) workshop in November 2014 assessed the risk to all New Zealand chondrichthyan taxa from commercial fishing. This report details outcomes from a repeat of that RA process in 2017 which used similar methodologies and personnel, and incorporated new information available since the 2014 risk assessment. The intention was for this RA to inform management and be a forerunner to a more quantitative (level 2) RA.

The qualitative RA used a modified Scale Intensity Consequence Analysis (SICA) approach. A data compilation exercise completed prior to the workshop allowed discussion and decisions about risk to be well informed. An expert panel then scored the risk to each taxon from commercial fishing, based on fishing information from the last five years and information on the species’ biological productivity. The assessment considered risk on a national (Exclusive Economic Zone (EEZ)) scale. This process scored both intensity and consequence of the fishery to the shark taxa on a scale of one to six (where one was low, and six was high). A total of 50 taxa were assessed out of the known New Zealand fauna of 112 chondrichthyans.

The rationale for the intensity and consequence scores for each taxon was documented. These intensity and consequence scores were then multiplied together to get a total risk score (with a possible maximum score of 36). Workshop participants also made recommendations about the presentation and utilisation of workshop outputs, as well as identifying key information gaps. The results are reported here within the three management classes of sharks (including rays, skates, and chimaeras) - Protected, Quota Management System (QMS) and non-QMS taxa. Basking shark remained the highest scoring protected species with an unchanged total risk score of 13.5. New data have been generated since the 2014 risk assessment, particularly for high-risk non-QMS shark species. Re-examination of all of the available data has resulted in changed evaluation of risk for a number of species. Plunket’s shark, thresher shark and shovelnose dogfish (all non-QMS species) have increased 2.5 risk points or more. Plunket’s shark is now considered the most at-risk shark (risk score = 22.5) due to a re-evaluation of its intensity score. Carpet shark (Non-QMS), electric ray (Non-QMS), and smooth and rough skates (both QMS) have all decreased more than 2.5 risk points due to new information on abundance or productivity. The highest risk QMS species are now rough skate, elephantfish, dark ghost shark, rig, spiny dogfish and school shark, all having a relatively high fishing intensity (scoring 6) and a moderate consequence score of 3, for a total risk score of 18. No consequence score greater than 4.5 was allocated (out of a maximum possible of 6) because available information did not suggest that commercial fishing is currently causing, or in the near future could cause, serious unsustainable impacts (the description of a score of five for total consequence). However, out of the 50 taxa considered in detail, the panel had low confidence in the risk scores for three of 11 QMS species, 26 of 36 non-QMS taxa and all three protected species. Some species that were evaluated in detail in 2014 were not re-evaluated in 2017, as the panel were confident risk was low, but not that it could be assessed well quantitatively.

The RA was designed to help prioritise management actions for shark taxa, noting that protected species are also given priority under the NPOA–Sharks (2013). The panel made several recommendations for high-risk or protected species regarding potential research options. These included better use of existing data, data grooming or analysis to improve inputs to assessment scores, improved taxonomy and training to underpin identification of sharks, and collection of more biological information to increase understanding of productivity (especially the ability of a taxon to withstand and to recover from fishing impacts). The RA panel also stressed that, particularly where abundance indices are lacking, the consequence scale was more relevant to risk than the total risk score which was often dominated by the level of intensity (masking differences in potential consequence). Taxa with high consequence scores have low productivity or presumed low productivity. In such cases, more information may improve the scores or our confidence in them, but in the interim a more precautionary approach to management was recommended by the panel.