Fish & fisheries on the Chatham Rise Statement of Evidence by Richard O Driscoll 16 October 2014
Scope of Evidence Fish distribution on Chatham Rise Fisheries on the Chatham Rise Fish spawning on the Chatham Rise Importance of Chatham Rise to hoki Summary Paragraph 19 of my evidence
Fish distribution on Chatham Rise Primary data source annual research surveys of 200-800 m depth in January 1992-2014 from RV Tangaroa Secondary data sources other research surveys and commercial catches Survey area 139,496 km 2 (revised consent area 5,207 km 2 = 3.7%) Paragraph 21 and Figure 1 of my evidence
Fish distribution on Chatham Rise More than 250 species of fish caught 1992-2010 Summarised data for 45 species with best information (43 fish, arrow squid, scampi) 32 species split into juveniles/adults Focused on past 10 years (971 trawls of which 27 were within revised consent area) Abundance in revised consent areas estimated by (agreed) statistical methods Paragraphs 22-28 and Table 1 of my evidence
Fish distribution on Chatham Rise None of the 45 species examined had more than 10% of its total Chatham Rise estimated biomass (averaged over past 10 years) within the revised consent area. Species/maturity groupings with the greatest concentration within the revised consent area were juvenile and adult lookdown dory, adult silverside, banded bellowsfish, juvenile white warehou, juvenile spiny dogfish, scampi, and juvenile ling. Paragraphs 29-32 and Table 2 of my evidence
Fish distribution summary My evidence (paragraphs 21-34) provides agreed summary of best available information Good understanding of adult and juvenile commercial fish distribution in January from research trawl surveys Distribution of fish may change over annual cycle and our understanding of distribution outside January is based on secondary data sources (other research surveys and commercial catches) Improved knowledge of seasonal fish distribution would require dedicated data collection throughout the year this would be very expensive Joint witness statement Fish & Fisheries
Fisheries on Chatham Rise Primary data source commercial catch and effort data from Ministry for Primary Industries databases Catch and effort allocated to revised consent area using agreed statistical methods Very little commercial effort within revised consent area in past 10 fishing years (2003/04 to 2012/13) no trawling since BPA Paragraph 56-60 and Table 4 of my evidence
Fisheries on Chatham Rise Total catch of 165.6 t from revised consent area in past 10 fishing years: 99 t by longline and 64 t trawl Catch includes 49 species or groups Most catch was ling (36.9%), followed by hoki (21.3%), spiny dogfish (15.4%), javelinfish (6.7%), and sea perch (5.2%) Catches in the revised consent area over the past 10 years contributed less than 0.5% of the catch of that species from the associated Quota Management Area (QMA) Paragraphs 61-64 and Table 5 of my evidence
Fisheries summary The Chatham Rise is an important and valuable commercial fishing area There is very little fishing effort and catch within the revised consent area Removal of prospecting permit area 55967 from consent application greatly reduced spatial overlap with commercial fishing Bottom trawling has been banned within much of revised consent area since introduction of Benthic Protected Area (BPA) in 2007, but even before establishment of BPA there was relatively little trawling Joint witness statement Fish & Fisheries
Fish spawning on Chatham Rise Primary data source female fish where gonad stages assessed from research trawls and MPI observers updated 1 July 2001 to 28 July 2014 Earlier summaries including reviews of unpublished and published literature by Hurst et al. 2000 and O Driscoll et al. 2003 28 species on research trawl database with more than 20 female gonad stages in area 43 to 44 S and 178 E to 178 W. Information summarised for these 28 species and for orange roughy Gonad stage data only available for 14 of 29 species from revised consent area from research trawls (mainly January) and 2 of 29 species from observer records since July 2001 No data for other species because not caught and/or not staged Paragraphs 47-50 and Table 3 of my evidence
Fish spawning on Chatham Rise Figure 7 of my evidence
Fish spawning on Chatham Rise Hake, ling, spiny dogfish, lookdown dory, sea perch, Bollons s rattail, dark ghost shark, hapuku, long-nosed chimaera, pale ghost shark, ribaldo, silver warehou, giant stargazer, and white warehou may spawn in and/or around the revised consent area. Although available data were sparse, there was no evidence that the revised consent area was particularly important as a spawning ground for any of the 29 species examined. Paragraphs 51-55 and Table 3 of my evidence
Fish spawning summary My evidence (paragraphs 47-55) provides agreed summary of best available information Based on best available information, there was no evidence that the revised consent area was an important spawning ground for any of the 29 fish species examined Caveat is that available data for some species are sparse - most of the research trawl data came from January and many species are known not to be spawning at this time of year Improved knowledge of timing and location of fish spawning would require dedicated data collection throughout the year this would be very expensive Joint witness statement Fish & Fisheries
Hoki on the Chatham Rise Hoki singled out because of importance as New Zealand s major deepwater fishery - current catch limit (from 1 October) 160,000 t Hoki assessed as two stocks western and eastern Chatham Rise main area of residence for adult eastern hoki & major juvenile area for both stocks Hoki catches from Chatham Rise 36,000 to 38,000 t in past 7 years Hoki catches from revised consent area very low (only 35 t total over past 10 years) Paragraphs 35-38 and Figure 2 of my evidence
Hoki on the Chatham Rise The main hoki spawning grounds are on the west coast South Island (western stock) and in Cook Strait (eastern stock), but some spawning also occurs on the east coast South Island, and on the Puysegur Bank in Southland A few hoki in spawning condition have also been recorded on the western Chatham Rise, but no spawning hoki have been observed in the revised consent area. Gonad stages of hoki from observer data 1989/90-2012/13 (blue = ripe, red = running ripe) Paragraphs 39-40 and Figure 3 of my evidence
Hoki on the Chatham Rise In most years more than 80% of New Zealand hoki between 2 and 3 years old are found on the Chatham Rise. Hoki from 1 2 years old (1+) are mainly caught at depths of 200 400 m on the western Chatham Rise. Larger hoki inhabit progressively deeper water and their spatial distribution expands. On average, for trawl surveys from 2005 14, 3.9% of the biomass of juvenile hoki and 3.7% of the biomass of adult hoki on the Chatham Rise was within the revised consent area, - indicating that hoki densities within the revised consent area were similar to average densities over the whole Chatham Rise. Paragraphs 41-45 of my evidence
Hoki on the Chatham Rise Figures 4-5 of my evidence
Hoki summary The Chatham Rise is the adult home ground for the eastern hoki stock and the major juvenile area for hoki of both stocks. It is also an important hoki fishing area. No spawning hoki have been detected within the revised consent area - young hoki move to the Chatham Rise from spawning grounds elsewhere. Hoki densities within the revised consent area in past 10 years were similar to average densities over the whole Chatham Rise Commercial catches of hoki from within the revised consent area have been very low Paragraphs 5-7 of my evidence
Joint witness statement Fish & Fisheries Summary The Chatham Rise is an important area for fish & fisheries The revised consent area is only a small proportion of area on Chatham Rise (3.7% of 200-800 m trawl survey area) with very limited commercial fishing Effects of mining will depend on spatial & temporal scale of impacts Disagreement between experts about level of uncertainty about likely spatial and temporal scale of impacts If direct and indirect impacts of mining are restricted to revised consent area then effects on commercial fish and fisheries are small