Longfin eel
Scientific name: |
A. dieffenbachii (long-finned), A. reinhardtii (Australian long-finned) |
Other names: |
All eels commercially caught in New Zealand, whether long- or short-finned, are ranked red, worst choice fish and should be avoided. There are no alternatives.
Eels are important freshwater predators. There are two main species of New Zealand eel: the endemic long-finned and native short-finned eels. They are caught in baited fyke nets or traditional hinaki. Both species are long-lived, spending part of their life-cycle at sea and part in freshwater environments. Eels breed only once, they leave their freshwater habitat to breed in the Pacific Ocean north of New Zealand. The long-finned eel is listed as a threatened species by the Department of Conservation. A third species – the Australian long-finned eel – is primarily found in Northland.
Eels are caught by relatively selective fyke nets. Concerns include the severely overfished status of the endemic long-finned eel, declining catch rates and the unknown sustainability of recent catch levels, managing two species (short-finned and long-finned) as one species, the lack of current or reference biomass estimates, and the lack of a management plan. The loss of habitat and impact of dams stopping eel migration have added to fishing risk to eels.
Not certified under any scheme.
New Zealand and exports of about $4.5 million in 2015 to markets including China, Belgium, South Korea and Canada.
Asssessment output
Long-fin and short-fin eels were separately assessed but both ranked red: worst choice seafood which should be avoided.
| Score: | Both long-fin and short-fin eels – E |
| Population size: | Unknown. One estimate of total eel population was 11,900 tonnes. |
| Annual catch limit: | Limit set at 839 tonnes from 2009-10 (418 tonnes North Island, 421 tonnes South Island, 11 tonnes Chatham Island). From 2016-17 the South Island quota was split between long-fin and short-fin/Australian long-fin, and the quota reduced to 322 tonnes (81 tonnes long-fin and 242 tonnes remainder). New Zealand totals are currently 163 tonnes long-fin, and 589 tonnes other eels. |
| Recorded catch: | Reported landings of 550 tonnes in 2014-15, the second-lowest catch in over 35 years. Long-fin eel catch was 116 tonnes and short-fin eel 434 tonnes: both the second-lowest landings since the 1960s. The short-fin catch is mostly females, as males tend to migrate before reaching the minimum legal size of 220g. The long-fin fishery includes both male and female eels. Catch limits are still nearly double current catches. |
| Stock trends: | Declining catch rates in all areas for long-fin eels and declines in many areas for short-fin eels. Declining number of juvenile “glass eels” swimming upstream, e.g. a quarter of what they were for long-fin eels in the 1970s on the Waikato River. Long-finned eels are classified as a threatened species by the Department of Conservation. “For long-fin eel, there exists an additional risk that the population of migrant eels might drop below a minimum threshold required for successful recruitment.” (Allibone et al, 2010). |
| MSY Status: | Unknown. “Estimates of current and reference biomass for any eel fish stock are not available.” |
| The Ministry of Primary Industries assessment plenary report includes: |
“There are no Level 1 Full Quantitative Stock Assessments on which to base specific recommendations on eel catch levels.” Long-fin: “Approximately 30% of available long-fin habitat in the North Island is either in reserves or in rarely/non-fished areas.” “Approximately 34% of currently available long-fin habitat on the South Island is either in reserves or in rarely/non-fished areas.” But only: “5% of habitat throughout New Zealand is in water closed to fishing where there is protected egress to the sea to ensure spawning escapement.” South Island areas (Westland, Otago and Southland): Overfishing is “likely if catch were to increase to the level of the TACC.” For other areas unknown. (MPI 2016, p329-355). |
| Score: | Both long-fin and short-fin eels – E |
| Distribution: | Eels are found throughout freshwater lakes, rivers and streams, plus some estuarine and coastal waters in New Zealand, including the Chatham Islands. |
| Maximum age (years): | 106 |
| Age at sexual maturity: | 11-56+ |
| Growth rate: | Variable |
| Reproductive output: | Low |
| Age exploited: | 8-17 |
| Ability to recover: | Low |
| Score: | Both long-fin and short-fin eels – A |
| Fishing method(s): | Fyke nets or hinaki |
| Habitat damage: | Very low |
| Habitat of particular significance: | some have been defined in New Zealand, but most remain unprotected. |
| Bycatch: | Other fish species caught include galaxiids, yellow-eyed mullet and koura. In Te Waihora bycatch may include bullies, black, yellowbelly, and sand flounder. Elsewhere bycatch can include flounder, grey mullet, yelloweye mullet, galaxiids and bullies. |
| Ecological effects: | The ecological effects of fishing are uncertain, but likely to be much less than the impact of land drainage and dams on eel habitat. Cumulatively, overfishing and habitat loss (including dams and drains preventing eel movement) are removing this important predatory species from New Zealand’s increasingly degraded freshwater systems. |
| Score: | Both long-fin and short-fin eels – C |
| Bycatch: | Seabirds including shags are caught in fyke nets. Shags known to be caught include pied, black, or little black shags. The risk of freshwater nets has not been estimated in the Ministry of Primary Industries’ seabird risk assessment. As there is no observer coverage, further research on seabird bycatch rates is needed. Freshwater fisheries bycatch is likely to be underestimated. |
| Score: | Both long-fin and short-fin eels – E |
| Management component: | Short-finned and ‘other’ (Australian long-finned) eels are managed as one component. Long-fins are now managed in all areas as a separate quota species. For all three species the stock arrangement has not been completely sorted. |
| Score: | Both long-fin and short-fin eels – C |
| Quota Management Species: | Yes: South Island since 2000, Chatham Island since 2003 and North Island since 2004. From 1 October 2015 the South Island eel fishery quota areas have been split into two quota species units: long-fin and short-fin. |
| Catch limits: | Yes, from 2004. |
| Management plan: | There is no approved freshwater or inshore plan. |
| Stock assessment: | No quantitative stock assessment. |
| Research: | There has been focused research on eels, in particular on endemic long-fin eels, but there is still no completed assessment. |
| Observer coverage: | Unobserved fishery. |
Fisheries map
Taken from the Ministry for Primary Industries’ Plenary report for fisheries management.
References
Report from the Fishery Assessment Plenary, May 2016: stock assessments and yield estimates. Part 1: Introductory Section to Hoki, Science Group, Ministry for Primary Industries; Ministry for Primary Industries (2016) Aquatic Environment and Biodiversity Annual Review 2015. Compiled by the Fisheries Management Science Team, Ministry for Primary Industries. 682p; The Guidebook to New Zealand Commercial Fish Species, 2007 Revised Edition, The New Zealand Seafood Industry Council Ltd; Seafood New Zealand, 2016. New Zealand Seafood Exports to December 2015. 133p; Hitchmough (comp) 2002 New Zealand Threat Classification System Lists, Department of Conservation. Allibone, R, David, B, Hitchmough, R, Jellyman, D, Ling, N, Ravenscroft, P and Waters, J (2010) ‘Conservation status of New Zealand freshwater fish, 2009’, New Zealand Journal of Marine and Freshwater Research, 1-17. 27 September 2010. Parliamentary Commissioner for the Environment (2013) On a pathway to extinction? An investigation into the status and management of the long-fin eel. 95p. MFish (2008) Freshwater Fisheries Species Draft Plan, 28p. G. D. Raby, A. H. Colotelo, G. Blouin-Demers, and S. J. Cooke (2011) Freshwater Commercial Bycatch: An Understated Conservation Problem BioScience (2011) 61 (4): 271-280 doi:10.1525/bio.2011.61.4.7. Graynoth, E.; Booker D. 2008. Biomass of long-fin eels in medium to large rivers. New Zealand Fisheries Assessment Report 2009/44. 24p. Graynoth, E.; Jellyman, D.J.; Bonnett, M. 2008. Spawning escapement of female long-fin eels. New Zealand Fisheries Assessment Report 2008/7. 57 p. Jellyman, D.J. 2008. Status of New Zealand fresh-water eel stocks and management initiatives. ICES Journal of Marine Science Advance Access published June 21, 2007. 2007 International Council for the Exploration of the Sea. Published by Oxford Journals. Martin, M.L.; Boubée, J.; Bowman, E. 2008. Recruitment of Freshwater Eels 2006–07 and 2007–08. Beentjes, M.P.; Sykes, J.; Crow, S. (2016). GIS mapping of the long-fin eel commercial fishery throughout New Zealand, and estimates of long-fin habitat and proportion fished. New Zealand Fisheries Assessment Report 2016/32. 53 p.