Zealand Sea Lions Research Articles

Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation

Sexual segregation (sex differences in spatial organisation and resource use) is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affect vulnerability to area-specific human activities. Although behavioural ecologists have proposed numerous hypotheses for this phenomenon, the underlying causes of sexual segregation are poorly understood. We examined the size-dimorphism and niche divergence hypotheses as potential explanations for sexual segregation in the New Zealand (NZ) sea lion (Phocarctos hookeri), a nationally critical, declining species impacted by trawl fisheries. We used satellite telemetry and linear mixed effects models to investigate sex differences in the foraging ranges of juvenile NZ sea lions. Male trip distances and durations were almost twice as long as female trips, with males foraging over the Auckland Island shelf and in further locations than females. Sex was the most important variable in trip distance, maximum distance travelled from study site, foraging cycle duration and percent time at sea whereas mass and age had small effects on these characteristics. Our findings support the predictions of the niche divergence hypothesis, which suggests that sexual segregation acts to decrease intraspecific resource competition. As a consequence of sexual segregation in foraging ranges, female foraging grounds had proportionally double the overlap with fisheries operations than males. This distribution exposes female juvenile NZ sea lions to a greater risk of resource competition and bycatch from fisheries than males, which can result in higher female mortality. Such sex-biased mortality could impact population dynamics, because female population decline can lead to decreased population fecundity. Thus, effective conservation and management strategies must take into account sex differences in foraging behaviour, as well as differential threat-risk to external impacts such as fisheries bycatch.

Interannual and individual variation in milk composition of New Zealand sea lions (Phocarctos hookeri)

Abstract In this study 308 milk samples were collected and analyzed from 181 individual female New Zealand sea lions (NZ sea lions; Phocarctos hookeri) breeding on Enderby Island (Auckland Islands). Samples were collected from the 1st part of early lactation (January and February) over a period of 7 years (1997, 1999–2003, and 2005). The effect of year, month, and maternal characteristics (body mass, body condition index [BCI], and age class) on the composition of milk was evaluated using a mixed model for repeated measures. The gross composition (± SD) of the milk was lipid (21.3% ± 8.1%), protein (9.4% ± 2.4%), water (67.9% ± 8.8%), ash (0.48% ± 0.06%), and energy content (10.3 ± 3.2 kJ/g). Overall, the quality of milk of the NZ sea lions in this study was relatively lower in solids and fats than that of other pinnipeds and, in particular, other sea lion species. There were significant effects of year and month on the concentration of lipids in milk, and of year and maternal age class on maternal body m...

Predicting interactions between recolonising marine mammals and fisheries: defining precautionary management

AbstractInteractions between fisheries and marine mammals have created costly and unresolved issues throughout the world. This study examines the spatial and resource overlaps between recolonising New Zealand sea lions, Phocarctos hookeri (Grey) (using satellite tracking) and local fisheries (using spatio‐temporal catch database) on the Otago coast, New Zealand. Around Otago, spatial and resource overlaps existed year‐round and it is predicted that incidental deaths in fishing gear and resource competition may arise as the sea lion population increases. Preventive management methods (e.g. marine protected areas) and monitoring studies (e.g. fish stock assessments) are proposed. The use of precautionary management could ensure sustainable profitable fisheries and successful recolonisation by sea lions around Otago, and it could be used as a case study for other areas with recovering marine mammal populations that interact with fisheries.

Body regional distribution and stratification of fatty acids in the blubber of New Zealand sea lions: implications for diet predictions

Fatty acids (FAs) from blubber are often analysed to assess the diet of marine mammals. However, distribution of blubber FAs is not necessarily uniform along the body. It is therefore important to understand the deposition of dietary fat to be able to estimate the diet. We analysed the FA compositions of the thoracic ventral (T region) blubber of 28 New Zealand (NZ) sea lions Phocarctos hookeri by-caught by the southern arrow squid Nototodarus sloani fishery. Each blubber sample was divided into an inner and an outer layer. For 16 of these 28 animals, the pelvic dorsal (P) region was also sampled. The influence of body region and layer was statistically tested on the distribution of blubber FAs. We found minimal differences between the P and T regions (3 out of 29 FAs). The outer blubber layer was more concentrated in short-chain monounsaturated FAs, and less concentrated in saturated FAs, but the degree of stratification was small. Diet predictions from quantitative FA signature analysis (QFASA) applied on different body regions were similar. When applied to different blubber layers, QFASA gave some variation in the contribution of rattails (~25 % in outer blubber vs. ~12 % in inner blubber). Nonetheless, diet predicted from both layers was dominated by similar prey species: octopus, hoki and rattails. Hoki and rattails shared a similar ecological niche. Therefore, feeding ecology of NZ sea lions inferred from the inner or the outer blubber would lead to the same conclusions. In the case of NZ sea lions, the outer layer of blubber, if the only sample accessible, could be a useful tissue for diet inference from FAs.

Using life‐history traits of New Zealand sea lions, Auckland Islands to clarify potential causes of decline

AbstractAnnual censuses of New Zealand (NZ) sea lions Phocarctos hookeri at the subantarctic Auckland Islands have indicated a decline in pup production of over 40% during the first decade of the 2000s. With this significant decline and likely decline in the population as a whole, population ecology theory hypothesizes that life‐history traits such as reproduction rate, survival or growth should improve, particularly if density‐dependency is playing a significant role in the population. This research examined whether changes in NZ sea lion pup production were associated with changes in adult abundance or population life‐history traits in an attempt to clarify potential causes of decline. Since 1998/1999, daily surveys of Sandy Bay, Enderby Island, were undertaken during the NZ sea lion breeding season (December–February). These surveys confirm that the number of adults at the breeding area has significantly declined during the period of pup production decline. There was no difference between years in mean pup birth date, but the ratio of pups to females ashore during peak pupping varied significantly. The sex ratio of pups at birth also varied from year to year, but with no significant variation overall. Pup mortality varied significantly only during years of epizootic events (1997/1998, 2001/2002 and 2002/2003). Pup birth mass showed little variation between 2000/2001 and 2006/2007, increasing slightly in the last 3 years of study. Pup mass at 3 weeks, although highly variable, showed no trend during the period of decline. Despite the significant decrease in pup production and breeding animals, not all life‐history traits relating to pup mass and survival or female fecundity improved. Research suggests that indirect fishing‐related pressures may influence some of these traits and that the NZ sea lion population was unlikely to have been influenced by density‐dependent factors or to have been at or near carrying capacity before the decline.

Increasing pup production of New Zealand sea lions at Campbell Island/Motu Ihupuku: can it continue?

New Zealand (NZ) sea lions (Phocarctos hookeri) were relisted as ‘nationally critical’ by the New Zealand Government in 2010, owing to recent severe declines in pup production at the Auckland Islands. However, research on Campbell Island/Motu Ihupuku indicates that this population's pup production is increasing. Between December 2009 and February 2010, surveys were undertaken aiming to determine production and early mortality rates (up to eight weeks) of NZ sea lion pups on Campbell Island. In total, 402 pups were tagged and a minimum pup production of 681 estimated from direct count. This estimate is 17% higher than the 2008 estimate of 583 pups and equates to 27% of the total pup production of the NZ sea lions in 2009–10. However, early pup mortality (55%) continues to be the highest recorded for any NZ sea lion breeding area and it is hypothesised that this breeding area is unlikely to be able to maintain this pup production increase.

Autumn diet of recolonising female New Zealand sea lions based at Otago Peninsula, South Island, New Zealand

New Zealand (NZ) sea lions (Phocarctos hookeri) are slowly recolonising the Otago coast, South Island, New Zealand. The increase in their numbers may lead to resource competition with other marine predators and fisheries. We determined the diet of female NZ sea lions at Otago during autumn. In total, 571 scats and 110 regurgitations were collected on Otago Peninsula during 2008 and 2009. Barracouta (Thyrsites atun) and jack mackerel (Trachurus sp.) were the two main prey species and accounted for 26% and 31% of the reconstituted biomass, respectively. This was consistent between two years. Only five other species contributed > 5% of the diet by biomass in either year. Prey species are all found on the narrow continental shelf surrounding Otago Peninsula. The main prey species of Otago NZ sea lions may be of higher energy content than prey in the Auckland Islands (remnant breeding area). Resource overlap with other marine predators and fisheries appears to occur around Otago Peninsula. A marine trophic model of the area off Otago Peninsula would help understanding potential competition between marine predators and fisheries in this area.

Population viability analysis of New Zealand sea lions, Auckland Islands, New Zealand’s sub-Antarctics: assessing relative impacts and uncertainty

A common issue faced in wildlife management is how to assess the uncertainty of potential impacts on the viability of a species or population. The pup production of New Zealand (NZ) sea lions (Phocarctos hookeri) has declined 50% in the last 12 years at their main breeding area, the Auckland Islands. The two major known atypical impacts on NZ sea lions are as follows: (1) the direct mortality as bycatch of trawling and (2) bacterial epizootics, which can affect reproduction and mortality. Both of these impacts include high levels of uncertainty, with fisheries data being variable due to percentage observer coverage and the effect of sea lion exclusion devises, while the timing and severity of bacterial epizootics are not predictable. In this paper, an age-structured model of the NZ sea lion population at the Auckland Islands was built to examine the predicted effects of fisheries mortality and catastrophes (bacterial epizootics), both separately and then combined, on population viability over a 100-year period using the VORTEX population viability analysis programme. These models are then compared against 15 years of empirical field data to determine the actual level of impacts being observed. Model results indicate that although naturally occurring epizootics reduce the growth rate of the population, it does not cause a decline in the Auckland Island population. However, sustained fisheries bycatch at current estimated levels, particularly considering its potential impact on adult female survival, could result in a population decline and possible functional extinction over the modelled time period.

In the shallow end: diving behaviour of recolonising female New Zealand sea lions (Phocarctos hookeri) around the Otago Peninsula

Female New Zealand sea lions ( Phocarctos hookeri (Gray, 1844)) at the Auckland Islands (remnant populations) are the deepest and longest diving otariids. These remnant populations are found at the margin of the historical range of the species. We hypothesized that diving behaviours of animals in the core of their historical range is less extreme owing to a better marine habitat. All female New Zealand sea lions (n = 13, aged 2–14 years) born on the Otago Peninsula (initial recolonising population) were equipped with time–depth recorders during April and May 2008, 2009, and 2010. The mean dive depth was 20.2 ± 24.5 m and mean dive duration was 1.8 ± 1.1 min, some of the lowest values reported for otariids. Otago female New Zealand sea lions did not exhibit two distinct diving specialisations as reported at the Auckland Islands. Otago adult females exceeded calculated aerobic dive limits in 7.1% of dives compared with 68.7% at the Auckland Islands. The contrasting differences in diving behaviour between Otago and the Auckland Islands suggest that Otago represents a better marine habitat for New Zealand sea lions, with food easily accessible to animals of all ages.

On‐land habitat preferences of female New Zealand sea lions at Sandy Bay, Auckland Islands

AbstractTerrestrial habitat is important for breeding in most pinnipeds. On land, most species remain near the shore, but New Zealand (NZ) sea lions, Phocarctos hookeri, often rest inland up to 1.5 km from the sea. Only three breeding areas of NZ sea lions exist today after the species was extirpated from its historical range (NZ mainland). The study was conducted at the Sandy Bay breeding colony, Auckland Islands, between December 2002 and March 2003. We used daily Global Positioning System locations of breeding females with pups and mapping in a Geographic Information System to determine terrestrial habitat use and preferences. Slopes less than 20° were preferred throughout the study. Females chose nursing sites with a seasonal change, preferentially based on the distance from the sea and habitat type. Comparisons with the other breeding colonies of NZ sea lions are presented and data are discussed in the context of the recolonization of the NZ mainland. Overall, the most suitable terrestrial habitat configuration for a breeding aggregation of NZ sea lions appears to be a sandy beach, with a wide area above high tide and moderate intertidal zone (for breeding), backed with vegetated sand dunes and forest on primarily flat terrain (for later dispersion).

Foraging behaviour indicates marginal marine habitat for New Zealand sea lions: remnant versus recolonising populations

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 432:247-256 (2011) - DOI: https://doi.org/10.3354/meps09176 Foraging behaviour indicates marginal marine habitat for New Zealand sea lions: remnant versus recolonising populations A. A. Augé1,*, B. L. Chilvers2, A. B. Moore3, L. S. Davis1 1Zoology Department, and 3School of Surveying, University of Otago, Dunedin 9016, New Zealand 2Aquatic and Threats Unit, Department of Conservation, Wellington 6011, New Zealand *Email: amelie.auge@gmail.com ABSTRACT: The New Zealand sea lion Phocarctos hookeri historically bred on the New Zealand mainland (South and North Islands). Subsistence hunting and later commercial sealing reduced its distribution to 3 breeding areas at the spatial edges of its historical distribution range, in the Auckland Islands (AI) and on Campbell Island. Here, we present foraging areas and foraging trips of female New Zealand sea lions from the Otago Peninsula, where a recolonising population has been found in the core of the historical range of the species. We compare the results with data from the AI in order to assess the theory that the spatial margin of a species’ distribution represents the lower end of habitat suitability. Female New Zealand sea lions at Otago had significantly smaller foraging ranges than females at the AI (mean 65% Kernel ranges: 47 ± 25 km2 versus 687 ± 109 km2), made shorter foraging trips (mean 11.8 ± 2.3 h versus 66.2 ± 4.2 h), and spent 40% less time at sea overall. Juvenile females at Otago from age 2 onwards could access foraging grounds used by adult females nursing pups; this is unlikely to be the case at the AI due to the large distances and associated depths of foraging grounds. Our study illustrates the theory that spatial marginality is related to habitat marginality. Existing management measures to mitigate the impact of bycatch in fisheries on declining remnant colonies around the AI were modelled based on populations exploiting optimal habitat. They should now integrate this new information. KEY WORDS: Phocarctos hookeri · Pinnipeds · Spatial · Marginal · Satellite tracking · Marine ­conservation Full text in pdf format PreviousNextCite this article as: Augé AA, Chilvers BL, Moore AB, Davis LS (2011) Foraging behaviour indicates marginal marine habitat for New Zealand sea lions: remnant versus recolonising populations. Mar Ecol Prog Ser 432:247-256. https://doi.org/10.3354/meps09176 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 432. Online publication date: June 27, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

The population decline of the New Zealand sea lion Phocarctos hookeri: a review of possible causes

The New Zealand (NZ) sea lion Phocarctos hookeri is NZ's only endemic pinniped and is listed as 'nationally critical'. The species breeds in the NZ sub-Antarctic: 71% of the population at the Auckland Islands (2010 pup production: 1814 39) and the remaining 29% on Campbell Island (726 pups in 2010). 2. Pup production at the Auckland Islands has declined by 40% since 1998 (1998: 3021 pups produced): only 1501 pups were born in 2009. This decline is directly linked to philopatric females not returning to breeding areas. While the Auckland Island population has declined, the Campbell Island population appears to be increasing slowly. 3. Potential reasons for the decline in the Auckland Island population, but not in the Campbell Island population, include non-anthropogenic factors: (i) disease epizoot- ics, (ii) predation, (iii) permanent dispersal or migration, (iv) environmental change; and anthropogenic impacts: (v) population 'overshoot', (vi) genetic effects, (vii) effects of contaminants, (viii) indirect effects of fisheries (i.e. resource competition) and (ix) direct effects of fisheries (i.e. by-catch deaths). Of the nine potential reasons examined here, six can be discounted (ii-vii). Bacterial epizootics (i) occur in the NZ sea lion population, but their impact has predominantly increased pup mortality, which is unlikely to cause the severe decline observed, as pup mortality throughout the species is naturally high and variable. 4. The most plausible hypotheses, based on available evidence, are that the observed decline, in particular, the decreasing number of breeding females in the Auckland Island population, is caused by (viii) fisheries-induced resource competition and (ix) fisheries-related by-catch. By-catch is the main known anthropogenic cause of mortality in the species. Competition with fisheries resulting in resource compe- tition, nutrient stress and decreased reproductive ability in NZ sea lions should be a priority area for future research.

An evaluation of hot-iron branding as a permanent marking method for adult New Zealand sea lions, Phocarctos hookeri

Context Studies of the population and behavioural ecology of pinnipeds require the ability to identify individuals over periods ranging from a single season to an entire lifetime. Aims The aims of this research were to examine the efficacy of hot-iron branding as a permanent marking technique including the legibility of marks over time and comparing estimates of survival for animals marked with brands versus flipper tags. Methods Adult female New Zealand sea lions (n = 135) aged between 4 and 24 years of age were hot-iron branded with four-digit numbers during the austral summer of 2000. Key results Ten years on, 100% of animals still alive could be identified from these brands. Over the 10-year research period, it was observed that the skin of fully healed individual brands could, on occasion, become lacerated due to injuries received from shark bites and/or bites from other sea lions, removing or temporarily reducing the legibility of single characters of some brands. However, these animals were still identifiable when all digits were considered – and scars could become an identifying mark in their own right. Key conclusions Survival estimates derived from branded versus tagged-only individuals were similar, although the variance associated with tagged-only survival estimates was higher, giving less robust estimates. This is likely a result of higher resight probabilities observed for branded individuals. Resighting of tags requires a close approach with a high associated level of disturbance to both the marked animal and those associated with it, especially when considered over the lifetime of the animal, while brands can be read from a considerable distance with little or no disturbance. Implications Thus, hot-iron branding can be an effective method for permanently identifying sea lions that provides robust parameter estimates, causes low disturbance in the resighting process, and does not compromise survival.

Quantitative fatty acid signature analysis on New Zealand sea lions: model sensitivity and diet estimates

We used quantitative fatty acid signature analysis (QFASA) to predict the long-term diet of New Zealand (NZ) sea lions (Phocarctos hookeri) incidentally caught in the NZ arrow squid (Nototodarus spp.) fishery. The QFASA model used fatty acid (FA) profiles based on 82 blubber samples of NZ sea lions bycaught between 2000 and 2006. First, the model was optimized by a series of simulations for which 1 model parameter—6 different sets of calibration coefficients (CCs) from different pinniped species and feeding regime, 2 sets of FAs, and the consideration of individual prey values, or mean prey values—varied each time. The best-fit parameters were those giving the lowest Kullback–Liebler distance values. Second, these parameters were used in a model to estimate the diet of NZ sea lions. QFASA was highly sensitive to the set of CCs applied. Across years the most important prey estimated with the best-fit CCs were southern arrow squid (Nototodarus sloani, 18–28% mass), hoki (Macruronus novaezelandiae, 10–27% mass), rattails (Macrouridae, 7–27% mass), and possibly scampi (Metanephrops challengeri, 1–19% mass). Despite the uncertainty on the accuracy of the match between the best-fit CCs used and the true FA metabolism of NZ sea lions, the variation of prey estimated among years was highly consistent with the trends of commercial catches during the same period, providing some confidence in the present QFASA predictions. The most important estimated prey were demersal species living mainly at depths .200 m that NZ sea lions encounter on the slopes of the Auckland Islands shelf. Our study emphasized the importance of these areas for bycaught NZ sea lions over the 1st half of the lactation period. DOI: 10.1644/09-MAMM-A-299.1.

Investigating foraging utilization distribution of female New Zealand sea lions, Auckland Islands

Detrimental interactions between marine mammals and fisheries are increasing worldwide. The ability to manage these interactions requires the knowledge of where and how interactions occur and the effects they have on species. Many pinnipeds are central place foraging colonial breeders who are restricted in foraging range during breeding. Here, we use a utilization distribution approach to examine the foraging habitats of lactating New Zealand (NZ) sea lions (Phocarctos hookeri) from Dundas and Enderby Islands, Auckland Islands. Annually, the NZ sea lions which breed on these two islands produce 83% of this Nationally Critical species’ pups. Satellite transmitters were attached to 55 females during 2001–2007. Data showed that NZ sea lions utilize the entire Auckland Island shelf with partial habitat partitioning between females from the two breeding islands. This habitat partitioning results in differing degrees of overlap with fisheries and therefore possible differing fishery-related impacts on breeding areas.

Serologic Evaluation of New Zealand Sea Lions for Exposure to Brucella and Leptospira spp.

A serologic survey of anti-Brucella and antileptospiral antibodies was conducted on 147 adult, female New Zealand sea lions (Phocarctos hookeri). Most sea lions (n=138) were sampled at Sandy Bay, Enderby Island, Auckland Islands (50°30'S, 166°17'E), January 2000-March 2005. Nine were sampled at Otago, New Zealand (46°0'S, 170°40'E); four in April 2008 and five in March 2009. Serum from one of the Enderby Island females was weakly positive for antibodies to Brucella abortus using the competitive enzyme-linked immunosorbent assay, and one female had a low titer for Leptospira interrogans serovar pomona using the microscope agglutination test. All serum samples from Otago animals were negative. Brucellosis and leptospirosis are therefore considered unlikely to play a major role in population dynamics of these populations, and the low antibody prevalence of these agents suggests that they are an unlikely source of infection for humans, wildlife, or domestic species on mainland New Zealand.

Age- and sex-specific survival estimates incorporating tag loss for New Zealand sea lions,Phocarctos hookeri

The estimation of life-history parameters for a threatened species is important for understanding its biology and helping to determine management options. This research investigates age- and sex-related survival estimates incorporating tag loss for New Zealand (NZ) sea lions (Phocarctos hookeri) from Sandy Bay, Enderby Island, Auckland Islands, New Zealand, using multistate mark-recapture data from known-age individuals over 8 years (1997–1998 to 2005–2006). Survival estimates and tag loss rates differed significantly by sex and age class, with adult males having the lowest tag retention of any age or sex class and females ≥ 3 years old having lower survival estimates than their male counterparts. The variability and lower female survival relative to males is a critical problem for NZ sea lions, because even small changes in adult female survival significantly affect population trends for such large, long-lived mammals.

Behavioural responses and attraction of New Zealand sea lions to on-land female decoys

Using decoys to attract gregarious animals is a common management practice, but rarely used for pinnipeds. We investigated the behavioural responses of New Zealand (NZ) sea lions, Phocarctos hookeri, at Sandy Bay, Enderby Island, to determine whether decoys can attract female sea lions and so could be useful for the establishment of new colonies. We deployed decoys near existing breeding aggregations for 4 hours at a time. One or a group of three artificial decoys, made of white fabric, attracted up to 54% of females coming ashore, of which 73% came close enough to sniff the decoys. Up to 62% of males coming ashore within 15 m either side of these decoys moved towards them. A single taxidermied female NZ sea lion did not attract females significantly more often than a single fabric one, but was investigated as if alive by males. It appears that female NZ sea lions are attracted to decoys by their colour, at least when located close to an existing group of females. A technique using decoys could be trialled to direct recolonising females to suitable pupping sites.

Growth and reproduction of female New Zealand sea lions

Abstract A sample of 834 female New Zealand sea lions (Phocarctos hookeri), which were aged and measured, was obtained between 1998 and 2001. In addition, the reproductive histories of 505 marked females from the Auckland Islands were recorded from 1998 to 2005. These data sets were used to investigate growth and reproductive rates. Length and weight ranged from 134 to 197 cm and 49 to 156 kg, respectively. A Gompertz growth model best described growth and predicted that females attained 90% of asymptotic length (161.7 cm) and weight (112.0) at ages 4 and 11 years, respectively. No significant differences were found in growth rates among years, nor between the 2 major breeding colonies in the Auckland Islands. Females reproduced between the ages of 3 and 26 years, with evidence of reproductive senescence starting at age 23 years. Although females up to age 28 years were observed, no females over 26 years were recorded as reproductive. Age-specific reproductive rate p(x) increased rapidly between ages 3 an...

Predicting Life-History Traits for Female New Zealand Sea Lions, Phocarctos hookeri: Integrating Short-Term Mark-Recapture Data and Population Modeling

The trade-off between survival and reproduction by individuals is central to understanding life-history parameters of a species. Few mammal species have life-history information from long-term research. Instead, demographic models are commonly utilized to investigate an individual’s life-history strategy, species dynamics, and population trends. This research investigates age-related survival and reproductive performance of adult female New Zealand (NZ) sea lions (Phocarctos hookeri), using multi-state mark-recapture data from known-age branded individuals over five years. The mark-recapture analysis was integrated with a population model to predict the lifetime reproductive output of female NZ sea lions. The integration of an analysis of short-term datasets with population modeling allows for the prediction of life-history parameters of long lived animals when long-term information is not available. While such approaches involve some caveats, it provides a framework for investigating population dynamics and is preferential to unsubstantiated assumptions. This technique can lead to better design and implementation of conservation management for long lived species.