Analysis of vessel movements and strategies using commercial catch and effort data from the New Zealand hoki fishery

1996 ◽  
Vol 53 (9) ◽  
pp. 2126-2136 ◽  
Author(s):  
M Vignaux
Keyword(s):  
New Zealand ◽  
Commercial Catch

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 Population Genetics of New Zealand Nemadactylus macropterus (tarakihi) and Characterisation of their Mitochondrial Genome

2021 ◽  
Author(s):  
◽  
Alexander Halliwell
Keyword(s):  
Genetic Diversity ◽  
New Zealand ◽  
Genetic Structure ◽  
East Coast ◽  
Demographic History ◽  
Variable Region ◽  
Sequencing Data ◽  
Commercial Catch ◽  
History Of ◽  
Hyper Variable Region

<p>Nemadactylus macropterus, commonly known as tarakihi in New Zealand is highly regarded by commercial and recreational fishers and considered a taonga by iwi and customary fisheries. For many years N. macropterus was New Zealand’s second most important commercial catch and is currently the third most valuable inshore commercial finfish fishery in which 90% is consumed by the domestic market. However, despite the apparent importance, relatively little is known about the population structure of the N. macropterus. In 2017 the first fully quantitative stock assessment was conducted on the east coast N. macropterus fisheries as one stock. Alarmingly, the east coast fishery was estimated to be 15.9% of the unexploited spawning biomass and predicted to have been declining for the past thirty years. In an effort to rebuild the fishery, several rebuild plans have been purposed and commercial catch limits have been reduced. In order to rebuild and successfully manage a viable future N. macropterus fishery, an understanding of demographic connectivity and genetic connectivity among N. macropterus populations is essential.  The overall goal of this thesis research was to investigate the population genetic structure, genetic diversity and demographic history of N. macropterus using fish sampled from around New Zealand. This was achieved by analysing hyper variable region one of mitochondrial DNA for 370 N. macropterus collected from 14 locations. No genetic differentiation was observed among the 14 locations, an indication that N. macropterus have a panmictic genetic structure. Furthermore, N. macropterus display a relatively high level of genetic diversity and appear to have a large stable population with a long evolutionary history. The Bayesian skyline analysis indicates the N. macropterus historic population has gone through two expansions. The mostly likely cause of this is an expansion before and after the last glacial maximum.  The genetic diversity and demographic history of N. sp was also studied using samples collected from around the Three Kings Islands of New Zealand. The complete mitochondrial genome of N. macropterus was reconstructed from bulk DNA sequencing data and a set of specific mtDNA primers were developed to amplify hyper variable region one. The DNA sequencing data provided by these primers with the addition of published control region sequences was used to reconstruct the Nemadactylus phylogeny.</p>

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.

Distribution and abundance of freshwater eels (Anguilla spp.) in Tasmania

1984 ◽  
Vol 35 (4) ◽  
pp. 463 ◽  
Author(s):  
RD Sloane
Keyword(s):  
New Zealand ◽  
Coastal Lagoons ◽  
Catch Per Unit Effort ◽  
Commercial Catch ◽  
North Eastern ◽  
Coastal Streams ◽  
Catch Statistics ◽  
The 1960S ◽  
Density And Biomass ◽  
Freshwater Eels

The distribution of A. australis australis Richardson and A. reinhardtii Steindachner in Tasmania was determined from electrofishing surveys and commercial catch records. A. a. australis is abundant in coastal streams and extends far inland in the major drainage systems to the main lakes in Tasmania's Central Highlands. Density and biomass estimates for A. a. australis in streams, <0.01-1 .40 m-2 and 0.04-23.01 g m-2, respectively, are similar to those recorded for A. australis schmidtii Phillipps in New Zealand and for A. anguilla L. in Europe, A. reinhardtii is restricted to coastal lagoons and the lower freshwater reaches and estuaries of streams in north-eastern Tasmania including Flinders Island. Substantial populations of A. reinhardtii reside in these areas (0.05 m-2, 114.66 g m-2 in Douglas River). Analysis of commercial catch statistics indicates that the initial eel yields from standing waterbodies were high in the 1960s by world standards, although landings and catch per unit effort have subsequently declined.

A length-based Bayesian stock assessment model for the New Zealand abalone Haliotis iris

2003 ◽  
Vol 54 (5) ◽  
pp. 619 ◽  
Author(s):  
Paul A. Breen ◽  
Susan W. Kim ◽  
Neil L. Andrew
Keyword(s):  
New Zealand ◽  
Stock Assessment ◽  
Assessment Model ◽  
Data Sets ◽  
Catch Per Unit Effort ◽  
Commercial Catch ◽  
Data Set ◽  
Future Directions ◽  
Common Component ◽  
Joint Posterior Distribution

We describe a length-based Bayesian model for stock assessment of the New Zealand abalone Haliotis iris (paua). We fitted the model to five data sets: catch-per-unit-effort (CPUE) and a fishery-independent survey index, proportions-at-length from both commercial catch sampling and population surveys, and tag–recapture data. We estimated a common component of error and used iterative re-weighting of the data sets to balance the residuals, removing the arbitrary data set weightings used in previous assessments. Estimates at the mode of the joint posterior distribution were used to explore sensitivity of the results to model assumptions and input data; the assessment itself was based on marginal posterior distributions estimated from Markov chain–Monte Carlo simulation. Assessments are presented for two stocks in the south of New Zealand. One may be recovering after recent catch reductions; the other is over-exploited and likely to decline further. Assessment for the first stock was robust; assessment for the second stock was sensitive to the CPUE data and may be too optimistic. We discuss future directions and potential problems with this approach.

scholarly journals Development and evaluation of catch per unit effort indices for southern blue whiting (Micromesistius australis) on the Campbell Island Rise, New Zealand

2005 ◽  
Vol 62 (6) ◽  
pp. 1131-1138 ◽  
Author(s):  
Stuart M. Hanchet ◽  
Ron G. Blackwell ◽  
Alistair Dunn
Keyword(s):  
New Zealand ◽  
Stock Assessment ◽  
Independent Data ◽  
Catch Per Unit Effort ◽  
Age Composition ◽  
Commercial Catch ◽  
Fourfold Increase ◽  
Fishing Strategies ◽  
Acoustic Surveys ◽  
Campbell Island

Abstract This paper develops standardized commercial cpue indices for a highly aggregated spawning fishery in New Zealand waters, and verifies the indices using fishery-independent data. Indices were calculated for all vessels using three different measures of effort, and for vessel subsets based on processing type (surimi and dressed), and relative experience in the fishery. Trends in cpue were consistent with trends in fishery-independent acoustic surveys, age composition of the commercial catch, and recent stock assessment results. In particular, the cpue indices tracked the more than fourfold increase in abundance from 1993 to 1996 associated with the recruitment of the strong 1991 year class, and the decline in relative abundance as this year class was fished down. Despite this being a highly aggregated spawning fishery, there was little evidence for hyperstability. There were also significant differences in fishing strategies of the fleets between periods of high and low fish abundance.

scholarly journals Population Genetics of New Zealand Nemadactylus macropterus (tarakihi) and Characterisation of their Mitochondrial Genome

2021 ◽  
Author(s):  
◽  
Alexander Halliwell
Keyword(s):  
Genetic Diversity ◽  
New Zealand ◽  
Genetic Structure ◽  
East Coast ◽  
Demographic History ◽  
Variable Region ◽  
Sequencing Data ◽  
Commercial Catch ◽  
History Of ◽  
Hyper Variable Region

<p>Nemadactylus macropterus, commonly known as tarakihi in New Zealand is highly regarded by commercial and recreational fishers and considered a taonga by iwi and customary fisheries. For many years N. macropterus was New Zealand’s second most important commercial catch and is currently the third most valuable inshore commercial finfish fishery in which 90% is consumed by the domestic market. However, despite the apparent importance, relatively little is known about the population structure of the N. macropterus. In 2017 the first fully quantitative stock assessment was conducted on the east coast N. macropterus fisheries as one stock. Alarmingly, the east coast fishery was estimated to be 15.9% of the unexploited spawning biomass and predicted to have been declining for the past thirty years. In an effort to rebuild the fishery, several rebuild plans have been purposed and commercial catch limits have been reduced. In order to rebuild and successfully manage a viable future N. macropterus fishery, an understanding of demographic connectivity and genetic connectivity among N. macropterus populations is essential.  The overall goal of this thesis research was to investigate the population genetic structure, genetic diversity and demographic history of N. macropterus using fish sampled from around New Zealand. This was achieved by analysing hyper variable region one of mitochondrial DNA for 370 N. macropterus collected from 14 locations. No genetic differentiation was observed among the 14 locations, an indication that N. macropterus have a panmictic genetic structure. Furthermore, N. macropterus display a relatively high level of genetic diversity and appear to have a large stable population with a long evolutionary history. The Bayesian skyline analysis indicates the N. macropterus historic population has gone through two expansions. The mostly likely cause of this is an expansion before and after the last glacial maximum.  The genetic diversity and demographic history of N. sp was also studied using samples collected from around the Three Kings Islands of New Zealand. The complete mitochondrial genome of N. macropterus was reconstructed from bulk DNA sequencing data and a set of specific mtDNA primers were developed to amplify hyper variable region one. The DNA sequencing data provided by these primers with the addition of published control region sequences was used to reconstruct the Nemadactylus phylogeny.</p>

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