Rohan Currey

This document contains a summary of information and research on aquatic environment issues relevant to the management of New Zealand fisheries. It is designed to complement the Ministry’s annual Reports from Fisheries Assessment Plenaries (e.g., the November Plenary, MPI 2015b, and the May plenary, MPI 2015a) and emulate those documents’ dual role in providing an authoritative summary of current understanding and an assessment of status relative to any overall targets and limits. However, whereas the Reports from Fisheries Assessment Plenaries have a focus on individual fishstocks, this report has a focus on aquatic environment fisheries management issues and biodiversity responsibilities that often cut across many fishstocks, fisheries, or activities, and sometimes across the responsibilities of multiple agencies.
This update has been developed by the Science Team within the Fisheries Management Directorate of the Regulation and Assurance branch, Ministry for Primary Industries (MPI). It does not cover all issues but, as anticipated, includes more chapters than previous editions. As with the Reports from Fisheries Assessment Plenaries, it is expected to change and grow as new information becomes available, more issues are considered, and as feedback and ideas are received. This synopsis has a broad, national focus on each issue and the general approach has been to avoid too much detail at a local, fishery, or fishstock level. For instance, the benthic (seabed) effects of mobile bottom‐fishing methods are dealt with at the level of all bottom trawl and dredge fisheries combined rather than at the level of a target fishery that, although it might be locally important, might contribute only a small proportion of the total impact. The details of benthic impacts by individual fisheries will be documented in the respective chapters in the May or November Report from the Fisheries Assessment Plenary, and linked there to the fine detail and analysis in Aquatic Environment and Biodiversity Reports (AEBRs), Fisheries Assessment Reports (FARs), and Final Research Reports (FRRs). Such sections have already been developed for several species in the Fishery Assessment Plenary Reports, and others will follow.
The first part of this document describes the legislative and broad policy context for aquatic environment and biodiversity research commissioned by MPI, and the science processes used to generate and review that research. The second, and main, part of the document contains chapters focused on various aquatic environment issues for fisheries management. Those chapters are divided into five broad themes: protected species; non‐ QMS (mostly fish) bycatch; benthic effects; ecosystem issues (including New Zealand’s oceanic setting); and marine biodiversity. A third part of the review includes a number of appendices for reference. This review is not yet comprehensive in its coverage of all issues or of all research within each issue, but attempts to summarise the best available information on the issues covered. Each chapter has been considered by the appropriate working group at least once.

Commission for the Conservation of Antarctic Marine Living Resources

CCAMLR is the 25-Member organisation responsible for the conservation and management of marine living resources in the Southern Ocean. The CAMLR Convention Area includes all waters south of the Antarctic Convergence and covers around 10 percent of the Earth’s surface.

Under the Convention, CCAMLR is required to maintain ecological relationships between harvested, dependent and related populations, and to prevent or minimise the risk of changes in the marine ecosystem that are not potentially reversible over two or three decades.

In its Convention Area, CCAMLR manages fisheries that target  Antarctic krill (Euphausia superba), mackerel icefish (Champsocephalus gunnari), Patagonian toothfish (Dissostichus eleginoides) and Antarctic toothfish (Dissostichus mawsoni). Antarctic krill and mackerel icefish are not currently fished in the Ross Sea.

An exploratory fishery for toothfish, primarily Antarctic toothfish, has operated in the Ross Sea since 1997. In the 2015 stock assessment, toothfish spawning stock biomass in the Ross Sea was estimated at ca. 71% of unfished levels, well above the target level of 50% that was set to ensure the stock maintains stable recruitment.

Toothfish Predators: In the Right Place at the Right Time

While toothfish remain relatively abundant in the Ross Sea, we are only beginning to understand their ecological relationships, in particular their potential importance as a prey species for predators such as Antarctic killer whales (Orcinus orca) and Weddell seals (Leptonychotes weddellii).

Toothfish spend much of their lives at depths (>1000m) that would prohibit foraging by many air breathing predators. However in key locations on the Ross Sea shelf, toothfish are found at depths (~600m) that are more accessible to diving predators. When these locations become ice-free in the austral summer, killer whales and Weddell seals are able to access these potential prey. Photo ID and satellite tagging data obtained by New Zealand and Italian researchers confirms that killer whales move from as far as the Kermadec Islands and northern New Zealand to the Ross Sea shelf, and the availability of a prey source like toothfish may well be a key factor.

Maintaining Ecological Relationships and Minimising Risk

For CCAMLR to ensure that it maintains the ecological relationships between toothfish and its predators, CCAMLR needs to understand these ecological relationships and then manage the toothfish fishery such that it minimises the risk of ecosystem changes.

Localised reductions in toothfish abundance in key areas such as the Ross Sea shelf may reduce prey availability for toothfish predators, as there appears to be no alternative fish prey in the Ross Sea that could adequately replace toothfish.

Marine mammal depredation of toothfish longlines, common in some CCAMLR fisheries, has not been observed in the Ross Sea. If killer whales learn to depredate toothfish longlines in the Ross Sea, or develop this behaviour elsewhere and then apply it in the Ross Sea, this may result in ecosystem changes that are unlikely to be reversible within two or three decades.

Proposal for a Ross Sea Region Marine Protected Area

To reduce the risk of such changes (and to address other objectives), CCAMLR is currently considering a joint New Zealand-United States proposal for a Ross Sea region Marine Protected Area4. The MPA proposal provides a mechanism for ensuring spatial segregation between fishing effort and key foraging areas for toothfish predators. If the MPA proposal is adopted, important areas such as the Ross Sea shelf would be closed to toothfish fishing.

If adopted, the Ross Sea region Marine Protected Area would be the world’s largest MPA, encompassing 1.55 million square kilometres, of which 1.02 million square kilometres would be no-take. Integral to the MPA proposal is a comprehensive research and monitoring plan that seeks to encourage collaborative research by all CCAMLR Members in the Ross Sea. This would involve establishing long-term multi-disciplinary studies in collaboration with international partners  to characterise the ecological relationships of toothfish, its predators and prey.

Killer whales of ecotype C (Orcinus orca, TCKW) were studied in McMurdo Sound, Antarctica, during Dec 2014-Jan 2015 by dart biopsy sampling and photo-identification (photo-ID). We collected 33 dart biopsy samples including 27 samples from killer whales (26 type C, 1 type B) and 6 samples from Antarctic minke whales (Balaenoptera bonaerensis). With the exception of 7 type-B killer whales (TBKW; 5 adults, 2 calves), all killer whales sighted in the McMurdo Sound region were TCKW. By combining images from our 2013/14 and 2014/15 with an existing catalogue compiled by the Orca Research Trust ('AKWIC') and photos submitted by 'citizen scientists', we have created an expanded photo-identification catalogue for Antarctic killer whales that is scheduled to go online in 2015. Preliminary analysis of the database provides evidence for long-distance migrations of TCKW between the Ross Sea and New Zealand waters: (a) One adult female TCKW has been re-sighted in both New Zealand waters and McMurdo Sound, Antarctica; (b) a large proportion of TCKW sighted in McMurdo Sound (33-55%) bear marks caused by cookiecutter sharks that are currently assumed to be limited to north of 50°S. TCKW have also been re-sighted between years in New Zealand waters and in McMurdo Sound, with a minimum distance of 11 km between inter-annual sightings, indicating that TCKW may show seasonal site fidelity to areas of high ecological significance.

This document contains a summary of information and research on aquatic environment issues relevant to the management of New Zealand fisheries. It is designed to complement the Ministry’s annual Reports from Fisheries Assessment Plenaries (e.g., the November Plenary, MPI 2014b, and the May plenary, MPI 2014a) and emulate those documents’ dual role in providing an authoritative summary of current understanding and an assessment of status relative to any overall targets and limits. However, whereas the Reports from Fisheries Assessment Plenaries have a focus on individual fishstocks, this report has a focus on aquatic environment fisheries management issues and biodiversity responsibilities that often cut across many fishstocks, fisheries, or activities, and sometimes across the responsibilities of multiple agencies.
This update has been developed by the Science Team within the Fisheries Management Directorate of the Regulation and Assurance branch, Ministry for Primary Industries (MPI). It does not cover all issues but, as anticipated, includes more chapters than previous editions. As with the Reports from Fisheries Assessment Plenaries, it is expected to change and grow as new information becomes available, more issues are considered, and as feedback and ideas are received. This synopsis has a broad, national focus on each issue and the general approach has been to avoid too much detail at a local, fishery, or fishstock level. For instance, the benthic (seabed) effects of mobile bottom-fishing methods are dealt with at the level of all bottom trawl and dredge fisheries combined rather than at the level of a target fishery that, although it might be locally important, might contribute only a small proportion of the total impact. The details of benthic impacts by individual fisheries will be documented in the respective chapters in the May or November Report from the Fisheries Assessment Plenary, and linked there to the fine detail and analysis in Aquatic Environment and Biodiversity Reports (AEBRs), Fisheries Assessment Reports (FARs), and Final Research Reports (FRRs). Such sections have already been developed for several species in the Fishery Assessment Plenary Reports, and others will follow.
The first part of this document describes the legislative and broad policy context for aquatic environment and biodiversity research commissioned by MPI, and the science processes used to generate and review that research. The second, and main, part of the document contains chapters focused on various aquatic environment issues for fisheries management. Those chapters are divided into five broad themes: protected species; non- QMS (mostly fish) bycatch; benthic effects; ecosystem issues (including New Zealand’s oceanic setting); and marine biodiversity. A third part of the review includes a number of appendices for reference. This review is not yet comprehensive in its coverage of all issues or of all research within each issue, but attempts to summarise the best available information on the issues covered. Each chapter has been considered by the appropriate working group at least once.

Ecotype B and C (TBKW, TCKW) killer whales (Orcinus orca) were studied in McMurdo Sound, Antarctica, in late January and early February 2014. While the unusually extensive break-out of the sea ice in the 2013-14 season limited opportunities for the collection of dart biopsies, three whales were sampled. In the period from 20-28 January, a total of 307 whales were detected including 297 TCKW and 10 ecotype B killer whales (TBKW) along a 20-30 nautical mile stretch of fast ice at the western margin of McMurdo Sound. Feeding behaviour of TCKW was recorded during 5 of the 8 flights. TCKWs with prey items held in their jaws were seen on 5occasions; in 3cases, the prey was clearly identifiable as toothfish (Dissostichus mawsoni). A large number of images were collected for photo- identification. Additional observations of hunting behaviour of Type B killer whales directed at seals and penguins were made from Scott Base between 30 Jan and 16 Feb 2014.

New Zealand inshore Set Net fishery operating in statistical area 022 is a commercial fishery of ~ 12 vessels that targets rig shark, elephant fish and school sharks. The Ministry for Primary Industries (MPI) has tested the use of electronic monitoring (EM) to document captures of Hector’s dolphins and other protected species and fishing location within the fishery. Project objectives were:
• to evaluate EM and methods of implementing automatic collection of at-sea fisheries data;
• to compare data collected by EM reviewers and at-sea observers; and
• to evaluate the needs of an operational program for the use of EM within the inshore Set Net fishery.

Understanding the reproductive parameters of very small or declining populations is of clear importance to conservation. From 1995 to 2011 we recorded calf production (n = 71) and calf survival for 27 breeding females in the bottlenose dolphin (Tursiops truncatus) population in Doubtful Sound, New Zealand; a population with a recent history of declining abundance. Overall, 67% of calves survived their first year, and 40% survived to 3 yr (or are 2 yr old and still alive). Most calves that died in the first year died in their first month (87%). Multiparous mothers (n = 18) showed high variation in calf survival. The most successful six had all but one of their 20 calves (95%) survive to 1 yr. Fourteen of the 20 (70%) survived to 3 yr, and another four are still alive and are 1 or 2 yr old. In contrast, the least successful seven mothers produced a similar number of calves (21), eight of which (38%) survived to 1 yr, and none to 3 yr. Here we describe calving seasonality and calf survival, observed over 16 yr, and show that large variation in reproductive success of individual females is an example of extreme demographic stochasticity in this small, endangered population.

This document contains a summary of information and research on aquatic environment issues relevant to the management of New Zealand fisheries. It is designed to complement the Ministry’s annual Reports from Fisheries Assessment Plenaries (e.g., the November Plenary, MPI 2012, and the May plenary, MPI 2013) and emulate those documents’ dual role in providing an authoritative summary of current understanding and an assessment of status relative to any overall targets and limits. However, whereas the Reports from Fisheries Assessment Plenaries have a focus on individual fishstocks, this report has a focus on aquatic environment fisheries management issues and biodiversity responsibilities that often cut across many fishstocks, fisheries, or activities, and sometimes across the responsibilities of multiple agencies.
This update has been developed by the Science Team within the Fisheries Management Directorate of the Resource Management and Programmes branch, Ministry for Primary Industries (MPI). It does not cover all issues but, as anticipated, includes more chapters than in 2011 and 2012. As with the Reports from Fisheries Assessment Plenaries, it is expected to change and grow as new information becomes available, more issues are considered, and as feedback and ideas are received. This synopsis has a broad, national focus on each issue and the general approach has been to avoid too much detail at a fishery or fishstock level. For instance, the benthic (seabed) effects of mobile bottom-fishing methods are dealt with at the level of all bottom trawl and dredge fisheries combined rather than at the level of a target fishery that might contribute only a small proportion of the total impact. The details of benthic impacts by individual fisheries will be documented in the respective chapters in the May or November Report from the Fisheries Assessment Plenary, and linked there to the fine detail and analysis in Aquatic Environment and Biodiversity Reports (AEBRs), Fisheries Assessment Reports (FARs), and Final Research Reports (FRRs). Such sections have already been developed for several species in the 2012 and 2013 Fishery Assessment Plenary Reports, and others will follow.
The first part of this document describes the legislative and broad policy context for aquatic environment and biodiversity research commissioned by MPI, and the science processes used to generate and review that research. The second, and main, part of the document contains chapters focused on various aquatic environment issues for fisheries management. Those chapters are divided into five broad themes: protected species; non-QMS fish bycatch; benthic effects; ecosystem issues (including New Zealand’s oceanic setting); and marine biodiversity. A third part of the review includes a number of appendices for reference. This review is not comprehensive in its coverage of all issues or of all research within each issue, but attempts to summarise the best available information on the issues covered. Each chapter has been considered by the appropriate working group at least once.

Patterns of habitat use by wide-ranging animals may change in response to pertur- bations within their environment. In 2009, a group of 15 bottlenose dolphins, known to be part of the population in Doubtful Sound, New Zealand, were seen in another nearby fiord. This popula- tion has been closely monitored since 1990, and this was the first time that a group from Doubtful Sound was seen elsewhere. Since this first occurrence there have been at least 6 other occasions on which ‘resident’ dolphins were missing for at least 3 d, to later reappear in the fiord. During these absences, the other members of the population were routinely sighted. We use capture- recapture modelling based on photo-ID data to demonstrate a dramatic difference in capture probability between 2005 to 2009 and 2010 to 2011. Given the extremely high capture probability in the first period, and the fact that field effort has significantly increased from 2009 through to 2011, it is unlikely that these groups were within the fiord and simply missed. These findings suggest the possibility that the habitat use of this population has changed to include relatively frequent excursions beyond the fiord complex.

This document contains a summary of information and research on aquatic environment issues relevant to the management of New Zealand fisheries and expands and updates the first version published in 2011 (MAF 2011). It is designed to complement the Ministry’s annual Reports from Fisheries Assessment Plenaries (e.g., MPI 2012a & b) and emulate those documents’ dual role in providing an authoritative summary of current understanding and an assessment of status relative to any overall targets and limits. However, whereas the Reports from Fisheries Assessment Plenaries have a focus on individual fishstocks, this report has a focus on aquatic environment fisheries management issues and biodiversity responsibilities that often cut across many fishstocks, fisheries, or activities, and sometimes across the responsibilities of multiple agencies. This update has been developed by the Science Team within the Fisheries Management Directorate of the Resource Management and Programmes branch, Ministry for Primary Industries (MPI). It does not cover all issues but, as anticipated, includes more chapters than the first edition in 2011. As with the Reports from Fisheries Assessment Plenaries, it is expected to change and grow as new information becomes available, more issues are considered, and as feedback and ideas are received. This synopsis has a broad, national focus on each issue and the general approach has been to avoid too much detail at a fishery or fishstock level. For instance, the benthic (seabed) effects of mobile bottom-fishing methods are dealt with at the level of all bottom trawl and dredge fisheries combined rather than at the level of a target fishery that might contribute only a small proportion of the total impact. The details of benthic impacts by individual fisheries will be documented in the respective chapters in the May or November Report from the Fisheries Assessment Plenary, and linked there to the fine detail and analysis in Aquatic Environment and Biodiversity Reports (AEBRs), Fisheries Assessment Reports (FARs), and Final Research Reports (FRRs). Such sections have already been developed for several species in both 2012 Fishery Assessment Plenary Reports, and others will follow. The first part of this document describes the legislative and broad policy context for aquatic environment and biodiversity research commissioned by MPI, and the science processes used to generate and review that research. The second, and main, part of the document contains chapters focused on various aquatic environment issues for fisheries management. Those chapters are divided into five broad themes: protected species; non-QMS fish bycatch; benthic effects; ecosystem issues (including New Zealand’s oceanic setting); and marine biodiversity. A third part of the review includes a number of appendices for reference. This review is not comprehensive in its coverage of all issues or of all research within each issue, but attempts to summarise the best available information on the issues covered. Each chapter has been considered by the appropriate working group at least once.

This document contains a summary of information and research on aquatic environment issues relevant to the management of New Zealand fisheries. It is designed to complement the Ministry of Fisheries’ annual report from the Fisheries Assessment Plenary (for example, Ministry of Fisheries 2011) and emulate that document’s dual role in providing an authoritative summary of current understanding and an assessment of status relative to any overall targets and limits. However, whereas the Report from the Fisheries Assessment Plenary has a focus on individual fishstocks, this report has a focus on aquatic environment fisheries management issues that often cut across many fishstocks, fisheries, or activities, and sometimes across the responsibilities of multiple agencies.
This first version does not cover all issues and is expected to change and grow as new information becomes available, more issues are considered, and as feedback and ideas are received. This synopsis has a broad, national focus on each issue and the general approach has been to avoid too much detail at a fishery or fishstock level. For instance, the benthic (seabed) effects of mobile bottom-fishing methods are dealt with at the level of all bottom trawl and dredge fisheries combined rather than at the level of a target fishery that might contribute only a small proportion of the total impact. The details of benthic impacts by individual fisheries will be documented in the respective chapters in the Report from the Fisheries Assessment Plenary and linked there to the fine detail and analysis in Aquatic Environment and Biodiversity Reports (AEBRs), Fisheries Assessment Reports (FARs), and Final Research Reports (FRRs). Such sections have already been developed for hoki, scampi, squid, and some highly migratory species in the 2010 Report from the Fisheries Assessment Plenary (not updated in 2011), and others will follow.
The first part of this document describes the legislative and broad policy context for aquatic environment research, and the main science processes used to generate and review that research. The second, and main, part of the document contains chapters focused on various aquatic environment issues for fisheries management. Those chapters are divided into five broad themes: protected species; non-QMS fish bycatch; benthic effects; ecosystem effects; and marine biodiversity. The third part includes a number of appendices for reference. This review is not comprehensive in its coverage of all issues or of all research within each issue, but attempts to summarise the best available information on the issues covered. Each chapter has been reviewed by the appropriate working group at least once but the specific wording has not been agreed to the extent that is common practice for working group reports from the fishery assessment working groups. As at June 2011, chapters have been developed for selected issues but others will follow in subsequent iterations of this document. The exception to this is the sea lion chapter which was revised in December 2011 to reflect important new research findings. Chapters for seabirds, Hector’s and Maui’s dolphins, and fish bycatch are high priorities for 2011/12.

Capture-recapture methods relying on dorsal fin natural markings have never been applied successfully to striped dolphins, Stenella coeruleoalba, and were rarely used to assess abundance of short-beaked common dolphins, Delphinus delphis. We used digital photo-identification to obtain abundance estimates of striped and common dolphins living in mixed groups in the Gulf of Corinth, Greece. The proportion of either species was calculated based on the relative number of photographs of adult animals showing relevant portions of their body during conspicuous surfacings. Striped dolphins and common dolphins averaged 95.0% and 3.2% of all individuals, respectively. Animals showing intermediate pigmentation accounted for another 1.8%. Striped dolphin numbers were relatively high, with a point estimate of 835 animals (95% CI = 631–1,106). Common dolphins numbers were low (point estimate 28 animals; 95% CI = 11–73) and individuals were scattered within striped dolphin groups, indicating that this common dolphin population may be nonviable. Within a semiclosed Gulf exposed to considerable anthropogenic impact, the future of both dolphin species is of concern due to their suspected geographic isolation and restricted extent of occurrence. Information provided here can be used to inform timely conservation efforts.

We applied temporal symmetry capture–recapture (TSCR) models to assess the strength of evidence for factors potentially responsible for population decline in bottlenose dolphins (Tursiops truncatus) in Doubtful Sound, New Zealand from 1995 to 2008. Model selection was conducted to estimate recruitment and population growth rates. There were similar levels of support for three different models, each reflecting distinct trends in recruitment. Modeling yielded low overall estimates of recruitment (0.0249, 95% CI: 0.0174–0.0324) and population growth rate (0.9642, 95% CI: 0.9546–0.9737). The TSCR rate of population decline was consistent with an estimate derived from trends in abundance (lambda = 0.9632, 95% CI: 0.9599–0.9665). The TSCR model selection confirmed the influence of a decline in the survival of calves (<1 yr old) since 2002 for population trends. However, TSCR population growth rates did not exceed 1 in any year between 1995 and 2008, indicating the population was declining prior to 2002. A separate reduction in juvenile survival (1–3 yr old) prior to 2002 was identified as a likely contributing factor in the population decline. Thus, TSCR modeling indicated the potential cause of the population decline in Doubtful Sound: cumulative impacts on individuals <3 yr old resulting in a reduced recruitment.

The bottlenose dolphin Tursiops truncatus population in Doubtful Sound, New Zealand, has declined by over 34% since 1995 and is subject to potential impacts from tourism and habitat modification via freshwater discharge from a hydroelectric power station. The bottlenose dolphin population in neighbouring Dusky Sound is exposed to much lower levels of tourism and the fiord receives only natural freshwater runoff. We used dorsal fin identification photographs from both pop- ulations to compare levels of epidermal disease and laser photogrammetry to measure the dorsal fin base length of calves (<1 yr old) to assess differences in calf size and birth seasonality between the populations. Epidermal lesions were common in both populations (affecting >95% of individuals), but lesion extent was 4 times higher in Doubtful Sound. Lesion extent was higher for female dolphins than for males in Doubtful Sound, but not in Dusky Sound. In Dusky Sound calves were larger at first observation and were born over a longer period. The short calving season in Doubtful Sound may be an adaptation to localized temperature conditions. Anthropogenic impacts may contribute to the higher levels of epidermal disease in the Doubtful Sound population. The higher extent of epidermal lesions in females and the smaller size of calves in Doubtful Sound may be a factor in the low survival of calves in the population.

Numerous globally abundant species are exposed to human impacts that threaten the viability of regional populations. Assessing and characterising the risks faced by these populations can have significant implications for biodiversity conservation, given the ecological importance of many such species. To address these risks, the IUCN is starting to conduct assessments of regional populations in addition to species-level assessments of conservation status. Here, we demonstrate a threat assessment process that is robust to uncertainty, applying the IUCN criteria to a regional population of bottlenose dolphins in Fiordland, New Zealand. We compiled available population-specific information to assess the population under the five Red List criteria. We estimated there were 205 Fiordland bottlenose dolphins (CV = 3.5%), using current estimates of abundance for two sub-populations and stochastic modelling of an earlier estimate for the third sub-population. Population trajectory and extinction risk were assessed using stochastic age-structured Leslie matrix population models. The majority of model runs met the criteria for classification as critically endangered (C1: 67.6% of runs) given the number of mature individuals (123; CV = 6.7%) and the predicted rate of population decline (average decline: 31.4% over one generation). The evidence of isolation of the population confirms this was an appropriate regional classification. This approach provided an assessment that was robust to uncertainty.

1.The bottlenose dolphins of Doubtful Sound, New Zealand are a declining population at the southern limit of the species' range, exposed to impacts from tourism and habitat modification. Patterns in apparent annual survival were analysed from photographic resightings of naturally marked adults (1990 to 2008) and calves within the first year of life (1994 to 2008) using capture-recapture models.
2.The most parsimonious model for adults provided a time-invariant, sex-invariant estimate of survival (ϕa(1990–2008)=0.9374; 95% CI: 0.9170–0.9530), marginally lower than prior estimates for wild bottlenose dolphins.
3.The most parsimonious model for calves indicated a significant time-variant decline in survival from an estimate similar to other populations (ϕc(1994–2001)=0.8621; 95% CI: 0.6851–0.9473) to a current estimate that is, to our knowledge, the lowest recorded for free-ranging bottlenose dolphins (ϕc(2002–2008)=0.3750; 95% CI: 0.2080–0.5782).
4.Information theoretic evidence ratios suggested that observed patterns in calf survival were 22 times more likely to be explained by a decline coincident with the opening of a second tailrace tunnel for a hydroelectric power station than by a decline in any other year or across multiple years.
5.Projections using an age-structured stochastic population model indicated that the current level of calf survival was unsustainable (population decline: 100% of model runs; population extinction: 41.5% of model runs) and was a key factor in the observed population decline in Doubtful Sound.

1. The bottlenose dolphin population in Doubtful Sound/Patea, New Zealand is declining and subject to potential impacts from tourism and habitat modification via freshwater discharge from the Manapouri hydroelectric power station. The bottlenose dolphin population in neighbouring Dusky Sound is exposed to much lower levels of tourism and the fiord receives only natural freshwater run-off.
2. We used dorsal fin identification photographs from the both populations to compare levels of epidermal disease. Further, we used laser photogrammetry to measure the dorsal fin base length of calves (< one year old) to assess differences in calf size and birth seasonality between the populations.
3. Epidermal lesions were common in both populations (affecting > 95% of individuals), but lesion severity (recorded as percentage cover) was four times higher in Doubtful Sound. Within Doubtful Sound, lesion severity was higher for females than males. No such differences were observed in Dusky Sound. Calves were larger and were born over a wider period in Dusky Sound.
4. The freshwater discharge into Doubtful Sound alters temperature and salinity regimes in the fiord, which may exacerbate naturally occurring epidermal disease. The increased incidence of disease in females and the smaller size of calves in Doubtful Sound may help to account for the low survival of calves in the population. The narrow calving season in Doubtful Sound may be an adaptation to localised temperature conditions.
5. In order to tease apart the effects of water temperature on calving season, and examine the potential influence of the freshwater discharge into Doubtful Sound, comparative studies of calving seasonality, calf survival, calf size, and sea-surface temperature will be needed in both Dusky and Doubtful Sounds.

The bottlenose dolphins (Tursiops truncatus) of Dusky Sound, Fiordland, New Zealand are a little‐studied group at the southern limit of the species range. Conducting a photo‐identification census and capture‐recapture analyses, we estimated there were 102 (CV = 0.9%) bottlenose dolphins in Dusky Sound during summer 2007/08, the first abundance estimate for this population. We did not encounter individuals from Doubtful Sound in Dusky Sound, suggesting little or no interchange between these neighbouring populations. Using a sex‐prediction model derived from laser‐metric photographs of dolphins in Doubtful Sound, we predicted the sexes of 79 individuals (98–99% of adults and sub‐adults) in Dusky Sound. Our predictions provided a sex ratio of 35 males to 44 females, not significantly different to a 1:1 ratio (G = 1.02, P > 0.05). High resighting rates of individual dolphins suggest the population may be resident, with dolphins observed throughout the entire fiord system.

The bottlenose dolphins of Fiordland, New Zealand, live at the southern limit of the species’ worldwide range. They are exposed to impacts from tourism and habitat modification, particularly in Doubtful Sound, and their conservation requirements are presently unclear. Dolphin abundance was estimated in Doubtful Sound using photo- identification census and capture-recapture techniques (56 individuals; 95% CI: 55- 57), detecting a decline of 34-39% over 12 years among adults and sub-adults (>3 years old). The cause of this decline was investigated via demographic modelling in Doubtful Sound and a comparative assessment of population status in Dusky Sound.
Capture-recapture modelling of photo-identification data compiled since 1990 yielded a constant adult survival rate marginally lower than prior estimates for wild bottlenose dolphins (!a(1990–2008) = 0.9374; 95% CI: 0.9170-0.9530). Survival of calves (<1 year old) declined to an unsustainable level that is thought to be the lowest recorded for wild bottlenose dolphins (!c(2002–2008) = 0.3750; 95% CI: 0.2080-0.5782) coincident with the opening of a second tailrace tunnel for a hydroelectric power station. Reverse-time capture-recapture modelling detected declines in recruitment (f(1994–2008) = 0.0249; 95% CI: 0.0174-0.0324) and population growth (!(1994–2008) = 0.9650; 95% CI: 0.9554- 0.9746) over time consistent with the decline in calf survival (<1 year old) and a separate reduction in juvenile survival (1 to 3 years old) reflecting cumulative impacts.
Dolphin abundance was estimated in Dusky Sound using photo-identification census and capture-recapture techniques (102 individuals; 95% CI: 100-104) providing no evidence of interchange with Doubtful Sound. A comparative assessment of health status between Doubtful and Dusky Sounds revealed skin lesioning was more severe in Doubtful Sound, particularly among females, and newborn calves appeared to be smaller and were born over a shorter period: factors that may contribute to the low levels of calf survival in Doubtful Sound. The Fiordland bottlenose dolphins were assessed under IUCN Red List regional criteria. The small size of the population (205 individuals; 95% CI: 192-219) combined with the projected rate of decline in stochastic matrix models (average decline: 31.4% over one generation) resulted in a recommended classification of Critically Endangered.

1. The bottlenose dolphin of Dusky Sound (Tursiops sp.) are a little studied group at the southern limit of the species range, while the neighbouring bottlenose dolphins of Doubtful Sound have been declining, and are subject to potential impacts from tourism and habitat change.
2. We applied photo identification census and capture- recapture techniques to estimate dolphin abundance in both Doubtful and Dusky Sounds. Further we applied laser photogrammetry and a sex prediction model derived from the population in Doubtful Sound to assess the likely sex ratio in Dusky Sound.
3. In Doubtful Sound, there were 56 (CV=1.3%) bottlenose dolphins, representing no net change in population status over the past 12 months. Four of five individuals missing from last year were under 4 years of age. Survival of newborns in the first year of life was 50%, confirming the importance of calf survival in population health.
4. In Dusky Sound, there were 102 (CV=0.9%) bottlenose dolphins, the first abundance estimate for this population. We did not encounter any individuals from Doubtful Sound in Dusky Sound (or vice versa) suggesting little or no interchange between populations.
5. We predicted the sexes of 79 individuals (representing 98- 99% of adults and sub-adults) in Dusky Sound. When our predictions were corrected for animals of known sex, the resulting sex ratio was 35 males to 44 females, not significantly different to an expected 1:1 ratio (G = 1.02, d.f. = 1, P = 0.312).
6. High resighting rates of individual dolphins suggest the population may be resident, similar to Doubtful Sound. However the clear seasonal shift in distribution observed in Doubtful Sound was absent from Dusky Sound. We discuss the consequences of our findings for the future management of the Fiordland bottlenose dolphins.

The bottlenose dolphins (Tursiops sp.) of Doubtful Sound, Fiordland, New Zealand, live at the southern limit of the species' worldwide range. They are subject to impacts from tourism and habitat modification. Photographic resightings of individually distinctive dolphins were gathered from 19 225 dorsal fin photographs taken during systematic surveys of the fiord. Field effort spanned nine seasons from summer 2004/2005 to summer 2006/2007, including 142 days on the water. Both capture-recapture and census approaches were taken in analysis. A total of 71 individuals were observed over the study period (54 adults, sub-adults and calves more than one year old and 17 newborn calves). Births were seasonal, occurring in the Austral summer and autumn, with calf survival (9 survivors of 17 births) lower than observed for this population in the past. Individual dolphins were resighted frequently within and across seasons, confirming the group is resident within the fiord year-round. Fifty-six bottlenose dolphins (CV=1.0%) were resident in Doubtful Sound in summer 2006/2007. Comparison with prior abundance estimates (for adults and sub-adults) indicates an apparent population decline of 34-39% over the past 12 years. This apparent decline suggests that precautionary management of human impacts is vital for the dolphins' long-term survival.

Bottlenose dolphins are a key resource of the tourism industry in Fiordland and are used on a daily basis by the tour operators offering cruises on the fiords. Recent studies have shown that the current levels of dolphin-boat interactions in this region cannot be sustained by bottlenose dolphins. Interactions have both short- and long- term effects on both individuals and their populations. Recent preliminary modelling work is showing that these effects can consequently be affecting the viability of the three bottlenose dolphin populations living in Fiordland, particularly the Doubtful Sound population and the population utilising Milford Sound which are exposed to higher interaction intensities. While we provided advice in 2002 to mitigate these effects, no management steps have been taken since then. As predicted in 2002, we are currently observing drastic changes in the bottlenose dolphin population living in Doubtful Sound which can be linked to the level of boat interactions to which they are current exposed. We argue that immediate steps need to be taken to mitigate the impact of tourism on this population which now numbers 56 individuals, representing a 20% decline in population abundance over the past 5 years. The creation of a multi-level marine mammal sanctuary would help, as we previously argued, minimise dolphin-boat interactions and still allow for the tourism sector to continue growing in Fiordland.

Sand hoppers (Amphipoda: Talitridae) are semiterrestrial crustaceans that feed upon stranded kelp. Their burrowing behaviour plays an important role in reintroducing nutrients into the sediment. The most abundant sand hopper on New Zealand's beaches is Talorchestia quoyana Milne-Edwards, 1840. It is host to a parasitic mermithid nematode, Thaumamermis zealandica Poinar, Latham and Poulin, 2002, which invariably kills its sand hopper host by emerging to complete its maturation and reproduction in a moist sand environment. The aim of the present study was to assess if the burrowing behaviour of Ta. quoyana showed pathologic consequences of infection by Th. zealandica. Two experiments were conducted to assess temporal variation in sand hopper burrowing in vitro. Parameters measured included the hour after sunrise and sunset that sand hoppers first emerged and the number of surface visits in the first hour after emergence. Across experiments, sand hopper burrowing behaviour showed considerable heterogeneity related to sand hopper length, sand hopper distribution, experimental series, and experimental moisture conditions. The presence of parasites was not a significant factor in determining sand hopper burrowing behaviour. The lack of pathological effect is surprising given the relative size of Th. zealandica.
Les puces de sable (Amphipoda: Talitridae) sont des crustacés semi-terrestres qui se nourrissent de varech échoué. Leur comportement fouisseur joue un rôle important dans l'enfouissement des nutriments dans le sédiment. La puce de sable la plus abondante sur les plages de la Nouvelle-Zélande est Talorchestia quoyana Milne-Edwards, 1840. Elle sert d'hôte à un nématode mermithidé parasite, Thaumamermis zealandica Poinar, Latham et Poulin, 2002, qui finit toujours par tuer son hôte, la puce de sable, lorsqu'il émerge pour compléter sa maturation et sa reproduction dans un milieu de sable humide. Le but de notre étude est d'évaluer si le comportement fouisseur de Ta. quoyana montre des signes pathologiques lors d'une infection à Th. zealandica. Nous avons mené deux expériences pour évaluer la variation temporelle du comportement fouisseur de la puce de sable in vitro. Les variables mesurées incluent les heures de la première émergence des puces de sable après le lever et le coucher du soleil, ainsi que le nombre de visites en surface faites dans l'heure qui suit l'émergence. D'une expérience à l'autre, les puces de sable affichent des comportements très hétérogènes en fonction de leur longueur corporelle et de leur répartition, ainsi que de la série expérimentale et des conditions expérimentales d'humidité. La présence de parasites n'est pas un facteur significatif dans la détermination du comportement fouisseur des puces de sable. L'absence d'effets pathologiques est étonnante, étant donné la taille relative de Th. zealandica.

Talorchestia quoyana is the most abundant sand hopper (Amphipoda: Talitridae) on New Zealand's beaches. These supralittoral detritivores are host to a parasitic mermithid nematode, Thaumamermis zealandica. In other systems, mermithids have been found to manipulate host behaviour to facilitate the continuation of their lifecycle. The aim of the present study was to determine if the burrowing behaviour of T. quoyana showed evidence of manipulation by T. zealandica. Two studies were conducted to assess the spatial and temporal patterns in sand hopper burrowing under field and laboratory conditions. Sand hopper burrowing behaviour showed considerable variation, related to sand hopper length, sand hopper distribution, month of collection, and experimental moisture conditions. The presence of parasites was not a significant factor in determining sand hopper burrowing behaviour, a result contrary to previous laboratory findings for this system. This study illustrates the benefits of combining both field and laboratory experiments to evaluate whether or not parasites alter host behaviour.