scholarly journals Status of New Zealand fresh-water eel stocks and management initiatives

2007 ◽  
Vol 64 (7) ◽  
pp. 1379-1386 ◽  
Author(s):  
Don J. Jellyman
Keyword(s):  
New Zealand ◽  
Fresh Water ◽  
Management Strategies ◽  
Wetland Loss ◽  
Commercial Catch ◽  
Anguilla Australis ◽  
Generation Times ◽  
The Status ◽  
Quota Management ◽  
Average Size

Abstract Jellyman, D. J. 2007. Status of New Zealand fresh-water eel stocks and management initiatives. – ICES Journal of Marine Science, 64: 1379–1386. New Zealand has two main species of fresh-water eel, shortfin (Anguilla australis), which is shared with Southeast Australia, and the endemic longfin eel (A. dieffenbachii). Both species are subject to extensive commercial and customary fishing. The shortfin is the smaller and shorter lived, with typical generation times for females ranging from 15 to 30 years; generation times for longfin females are double this. The distribution and the abundance of both species have been compromised by habitat modifications, shortfins, the more lowland species, being affected by wetland loss, and longfins by weirs and dams. Although there are few concerns about the status of shortfins, there is increasing evidence of overexploitation of longfins, including reduced recruitment, reduction in catch rates, reduction in abundance and average size, and a regional reduction in the proportion of females. Eels are managed under the quota management system, although individual and regional quotas are set from catch histories because biological parameters are inadequate. Maori, New Zealand's indigenous people, have been allocated 20% of commercial quota, with additional quota set for customary take. The annual commercial catch of eels has halved over the past decade, and is now ∼700–800 t, shortfins comprising 66% of catches. Recent management developments have included enhancement of upstream waters with juvenile eels, consolidation of processing into fewer but larger units, setting aside of additional reserve areas to increase escapement of silver eels, increased management involvement of Maori, and development of regional management strategies.

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
New Zealand ◽  
Management System ◽  
Stock Assessment ◽  
Catch Per Unit Effort ◽  
Commercial Catch ◽  
The North ◽  
Anguilla Australis ◽  
Unit Effort ◽  
Access Rights ◽  
Quota Management

<em>Abstract.</em>—The New Zealand eel fishery comprises two species, the shortfin eel <em>Anguilla australis </em>and the New Zealand longfin eel <em>A. dieffenbachii</em>. A third species, the speckled longfin eel <em>A. reinhardtii</em>, is present in small numbers in some areas. Major fisheries in New Zealand are managed under the Quota Management System. Individual transferable quotas are set as a proportion of an annual total allowable commercial catch. The Quota Management System was introduced into the South Island eel fishery on 1 October 2000 and the North Island fishery on 1 October 2004. Freshwater eels have particular significance for customary Maori. Management policies allow for customary take and the granting of commercial access rights on introduction into the Quota Management System. Eel catches have remained relatively constant since the early 1970s. The average annual catch from 1989–1990 to 2001–2002 (fishing year) was 1,313 mt. Catch per unit effort remained constant from 1983 to 1989 and reduced from 1990 to 1999. Statistically significant declines in catch per unit effort for New Zealand longfin eel were found in some areas over the latter period. For management, an annual stock-assessment process provides an update on stock status.

scholarly journals Aspects of the Biology of Juvenile Freshwater Eels (Anguillidae) in New Zealand

2021 ◽  
Author(s):  
◽  
Donald John Jellyman
Keyword(s):  
New Zealand ◽  
Fresh Water ◽  
Habitat Preferences ◽  
Spring Tide ◽  
Age Groups ◽  
Upstream Migration ◽  
Coastal Lake ◽  
Anguilla Australis ◽  
Glass Eels ◽  
Freshwater Eels

<p>The early freshwater life of the two species of New Zealand freshwater eels, Anguilla australis schmidtii Phillipps and A. dieffenbachii Gray was studied involving an examination of 8131 glass-eels, 5275 migratory elvers, and 4291 resident eels of less than 26 cm. Most eels were collected from the Makara Stream, Wellington by set-net, hand-net and electric fishing. These extensive samples together with subsidiary collections from elsewhere in New Zealand show that glass-eels of both species arrive in fresh-water from July to December. Their otoliths indicate a marine larval life of about 18 months but it is not possible as yet to locate the precise oceanic spawning areas. Migratory movements of glass-eels are in two phases: an invasion of fresh-water from the sea and an upstream migration. The former occurs only at night with a periodicity corresponding to the daily ebb-flood tidal rhythms. There is a seasonal reversal in this response which is attributable to the onset of the behavioural transition taking place prior to the second migratory phase. Increased pigmentation and changes in response to light, flowing fresh-water and schooling tendencies characterise this latter migration which occurs primarily at spring tide periods. Such juvenile eels show specific habitat preferences and a high degree of olfactory differentiation of water types. This behaviour, together with pigment development and physical tolerances, was studied in the laboratory. Measurements of invading glass-eels show that mean length, weight and condition all decline throughout the season of arrival but mean vertebral numbers remain constant. An upstream migration of small eels (elvers) occurs each summer and is readily observed at many hydro-electric stations. These migrations, comprising eels of mixed sizes and age groups, penetrate progressively further upstream each year. In both species, scales begin formation at body lengths of 16.5-20 cm. All features of scale formation, including the number of scale rings, are related to length with relative differences in rate of development occurring between the species. In contrast to scale rings, otolith rings are annual in formation and become visible after grinding or burning the otolith. Growth rates established for 273 eels to 29 cm in length from the Makara Stream, Wellington, are slow, with mean annual increments of 2.2 and 2.1 cm respectively for shortfins and longfins. In contrast, shortfins from a coastal lake near Wellington reach 26 cm in their third year of freshwater life. Length-weight relationships for small eels are given together with mean monthly condition factors. Growth studies on elvers held in a multiple tank unit in which temperature, density, and amount and frequency of feeding could be controlled, show that young eels grow more slowly than normal under such conditions. However, growth appears optimum at 20 degrees C with a feeding rate of 5-7% body weight per day. Feeding efficiency decreases with higher temperatures. At both glass-eel and elver stages, shortfins adapt and survive better under artificial conditions.</p>

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
New Zealand ◽  
Substantial Reduction ◽  
Theoretical Models ◽  
Commercial Fishing ◽  
Silver Eel ◽  
Glass Eel ◽  
Frequency Distributions ◽  
Anguilla Australis ◽  
The Status ◽  
Commercial Glass

<em>Abstract.—</em>The two main species of freshwater eels in New Zealand, the shortfin <em>Anguilla australis </em>and the endemic longfinned eel <em>A. dieffenbachii</em>, are extensively commercially exploited and also support important customary fisheries. Since there are no commercial glass eel fisheries in New Zealand, other indices must be used to indicate changes in recruitment over time. While there is some anecdotal evidence of reductions in glass eel recruitment, there is evidence of poorly represented cohorts of longfins within some populations, and modeling of these data indicate a substantial reduction in recruitment over the past two decades. Growth of both species is typically slow at 2–3 cm per year, meaning that both species are susceptible to commercial capture for many years until spawning escapement. Extensive commercial fishing has resulted in more substantial changes in length-frequency distributions of longfins than in shortfins; likewise, regional reductions in catch per unit effort are more significant for longfins. Theoretical models of silver eel escapement indicate that longfin females are especially susceptible to overexploitation. Shortfins would have been more impacted than longfins by loss of wetlands, but the impact of hydro stations on upstream access for juvenile eels and downstream access for silver eels would have been more severe for longfins. Overall, there is no clear evidence that the status of shortfin eel stocks has been seriously compromised by the extensive commercial eel fishery, but there is increasing evidence that longfins are unable to sustain present levels of exploitation.

scholarly journals Aspects of the Biology of Juvenile Freshwater Eels (Anguillidae) in New Zealand

2021 ◽  
Author(s):  
◽  
Donald John Jellyman
Keyword(s):  
New Zealand ◽  
Fresh Water ◽  
Habitat Preferences ◽  
Spring Tide ◽  
Age Groups ◽  
Upstream Migration ◽  
Coastal Lake ◽  
Anguilla Australis ◽  
Glass Eels ◽  
Freshwater Eels

<p>The early freshwater life of the two species of New Zealand freshwater eels, Anguilla australis schmidtii Phillipps and A. dieffenbachii Gray was studied involving an examination of 8131 glass-eels, 5275 migratory elvers, and 4291 resident eels of less than 26 cm. Most eels were collected from the Makara Stream, Wellington by set-net, hand-net and electric fishing. These extensive samples together with subsidiary collections from elsewhere in New Zealand show that glass-eels of both species arrive in fresh-water from July to December. Their otoliths indicate a marine larval life of about 18 months but it is not possible as yet to locate the precise oceanic spawning areas. Migratory movements of glass-eels are in two phases: an invasion of fresh-water from the sea and an upstream migration. The former occurs only at night with a periodicity corresponding to the daily ebb-flood tidal rhythms. There is a seasonal reversal in this response which is attributable to the onset of the behavioural transition taking place prior to the second migratory phase. Increased pigmentation and changes in response to light, flowing fresh-water and schooling tendencies characterise this latter migration which occurs primarily at spring tide periods. Such juvenile eels show specific habitat preferences and a high degree of olfactory differentiation of water types. This behaviour, together with pigment development and physical tolerances, was studied in the laboratory. Measurements of invading glass-eels show that mean length, weight and condition all decline throughout the season of arrival but mean vertebral numbers remain constant. An upstream migration of small eels (elvers) occurs each summer and is readily observed at many hydro-electric stations. These migrations, comprising eels of mixed sizes and age groups, penetrate progressively further upstream each year. In both species, scales begin formation at body lengths of 16.5-20 cm. All features of scale formation, including the number of scale rings, are related to length with relative differences in rate of development occurring between the species. In contrast to scale rings, otolith rings are annual in formation and become visible after grinding or burning the otolith. Growth rates established for 273 eels to 29 cm in length from the Makara Stream, Wellington, are slow, with mean annual increments of 2.2 and 2.1 cm respectively for shortfins and longfins. In contrast, shortfins from a coastal lake near Wellington reach 26 cm in their third year of freshwater life. Length-weight relationships for small eels are given together with mean monthly condition factors. Growth studies on elvers held in a multiple tank unit in which temperature, density, and amount and frequency of feeding could be controlled, show that young eels grow more slowly than normal under such conditions. However, growth appears optimum at 20 degrees C with a feeding rate of 5-7% body weight per day. Feeding efficiency decreases with higher temperatures. At both glass-eel and elver stages, shortfins adapt and survive better under artificial conditions.</p>

A bioeconomic analysis of management strategies for rebuilding and maintenance of the NSS rock lobster (Jasus edwardsii) stock in southern New Zealand

2005 ◽  
Vol 62 (7) ◽  
pp. 1553-1569 ◽  
Author(s):  
Daniel S Holland ◽  
Nokome Bentley ◽  
Philippe Lallemand
Keyword(s):  
New Zealand ◽  
Economic Performance ◽  
Performance Indicators ◽  
Management Strategies ◽  
Rock Lobster ◽  
Rule Based ◽  
Alternative Management ◽  
Management Objectives ◽  
Jasus Edwardsii ◽  
Quota Management

We evaluated alternative management strategies for the Otago and Southland rock lobster (Jasus edwardsii) fisheries in New Zealand. We compare a number of decision-rule-based management strategies and assess amalgamation of the two separate quota management areas that currently comprise the fishery. The analysis combines a spatial sex- and length-structured simulation model of the fishery with an economic module that converts catches and effort into revenues and costs. We compare performance of alternative management strategies using a variety of biological and economic performance indicators relevant to a range of management objectives identified by stakeholders. The results demonstrate the importance of modelling economic performance, since the relative performance of different management strategies differ when considering catch versus net revenues. The analysis also reveals important distributional issues, since some strategies that increase the overall value of the fishery create both winners and losers.

scholarly journals Research on invasive pests and diseases in New Zealand and the law

2012 ◽  
Vol 65 ◽  
pp. 281-288
Author(s):  
D.A.J. Teulon ◽  
K.S.H. Boyd Wilson ◽  
A. Holton ◽  
G.S. Ridley
Keyword(s):  
New Zealand ◽  
Rapid Development ◽  
Management Strategies ◽  
Legal Framework ◽  
Hazardous Substances ◽  
Invasive Pests ◽  
Pests And Diseases ◽  
Research Activities ◽  
Plant Pest ◽  
The Status

Two New Zealand statutes have important implications for research with organisms not previously found in New Zealand and either incidentally or illegally introduced The Biosecurity Act 1993 and the Hazardous Substances and New Organisms Act 1996 define the legal framework and allowable activities for unwanted and new organisms respectively Aspects of these Acts that are relevant to research activities possible with plant pest and disease organisms after their discovery in particular those organisms requiring rapid development of management strategies and tools are summarised The need for accurate detailed and accessible lists of unwanted and new organisms and the need for the Ministry for Primary Industries (MPI) and the Environmental Protection Authority (EPA) to respond rapidly when the status of these organisms needs to be changed is highlighted Consideration should be given to making the legislation concerning new organisms more applicable to incidentally or illegally introduced organisms

Pathways ahead for New Zealand hill country farming

2016 ◽  
Vol 78 ◽  
pp. 73-82 ◽  
Author(s):  
F.G. Scrimgeour
Keyword(s):  
New Zealand ◽  
Rural Communities ◽  
New Technologies ◽  
Service Providers ◽  
Farming Systems ◽  
Hill Country ◽  
The Status ◽  
And Performance ◽  
Hill Farming ◽  
The Hill

This paper provides a stocktake of the status of hill country farming in New Zealand and addresses the challenges which will determine its future state and performance. It arises out of the Hill Country Symposium, held in Rotorua, New Zealand, 12-13 April 2016. This paper surveys people, policy, business and change, farming systems for hill country, soil nutrients and the environment, plants for hill country, animals, animal feeding and productivity, and strategies for achieving sustainable outcomes in the hill country. This paper concludes by identifying approaches to: support current and future hill country farmers and service providers, to effectively and efficiently deal with change; link hill farming businesses to effective value chains and new markets to achieve sufficient and stable profitability; reward farmers for the careful management of natural resources on their farm; ensure that new technologies which improve the efficient use of input resources are developed; and strategies to achieve vibrant rural communities which strengthen hill country farming businesses and their service providers. Keywords: farming systems, hill country, people, policy, productivity, profitability, sustainability

The status of Gideon Mantell's “first” Iguanodon tooth in the Museum of New Zealand Te Papa Tongarewa

1997 ◽  
Vol 24 (3) ◽  
pp. 397-421 ◽  
Author(s):  
JOHN C. YALDWYN ◽  
GARRY J. TEE ◽  
ALAN P. MASON
Keyword(s):  
New Zealand ◽  
Charles Lyell ◽  
The Status ◽  
History Of ◽  
Gideon Mantell

A worn Iguanodon tooth from Cuckfield, Sussex, illustrated by Mantell in 1827, 1839, 1848 and 1851, was labelled by Mantell as the first tooth sent to Baron Cuvier in 1823 and acknowledged as such by Sir Charles Lyell. The labelled tooth was taken to New Zealand by Gideon's son Walter in 1859. It was deposited in a forerunner of the Museum of New Zealand, Wellington in 1865 and is still in the Museum, mounted on a card bearing annotations by both Gideon Mantell and Lyell. The history of the Gideon and Walter Mantell collection in the Museum of New Zealand is outlined, and the Iguanodon tooth and its labels are described and illustrated. This is the very tooth which Baron Cuvier first identified as a rhinoceros incisor on the evening of 28 June 1823.

scholarly journals An unlikely partnership? New Zealand–South Korea bilateral cooperation and Antarctic order

Polar Record ◽  
2021 ◽  
Vol 57 ◽  
Author(s):  
Patrick Flamm
Keyword(s):  
New Zealand ◽  
South Korea ◽  
World Politics ◽  
Global Power ◽  
Political Interests ◽  
Vested Interests ◽  
The Status ◽  
Bilateral Cooperation ◽  
And Performance ◽  
The Cold War

Abstract While the Antarctic Treaty System intended to keep Antarctica an area of international cooperation and science free from militarisation and international conflict, the region has not been completely shielded from global power transitions, such as decolonisation and the end of the Cold War. Presently, emerging countries from Asia are increasingly willing to invest in polar infrastructure and science on the back of their growing influence in world politics. South Korea has also invested heavily in its Antarctic infrastructure and capabilities recently and has been identified as an actor with economic and political interests that are potentially challenging for the existing Antarctic order. This article first assesses the extent and performance of the growing bilateral cooperation between South Korea and one of its closest partners, New Zealand, a country with strong vested interests in the status quo order. How did the cooperation develop between these two actors with ostensibly diverging interests? This article finds that what may have been a friction–laden relationship, actually developed into a win-win partnership for both countries. The article then moves on to offer an explanation for how this productive relationship was made possible by utilising a mutual socialisation approach that explores socio-structural processes around status accommodation.

Senecio lautus complex in Australia. I. Taxonomic considerations and discussion of some of the related taxa from New Zealand

1964 ◽  
Vol 12 (2) ◽  
pp. 282 ◽  
Author(s):  
SI Ali
Keyword(s):  
New Zealand ◽  
Zealand Population ◽  
The Status ◽  
First Time

Reasons for the retention of the name Senecio lautus Forst. f. ex Willd. for both New Zealand and Australian forms are advanced. It is concluded that the New Zealand population should be given the status of a subspecies. Synonymy of S. lautus subsp. lautus and typification of various names involved are discussed. S. glaucophyllus subsp. discoideus (T. Kirk) Ornd. is reported for the first time from Tasmania.

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