Patterns and Trends of Crocodile Trade from Tanah Papua, Indonesia

Crocodylus porosus and C. novaeguineae are two protected and tradable crocodile species in Indonesia. Therefore, precautionary principles are needed in their utilization to ensure sustainability. Although the commodity from these species is traded domestically and internationally, the broader picture of its use in Indonesia is less known. The objectives of the study were to: (1) analyze the domestic trade of crocodiles, and (2) analyze the international trade of crocodiles. The analysis was conducted using data of direct utilization sourced from the wild in the form of skin and hatchlings, data on domestic transport permits, CITES export permits, and the CITES trade database. The study suggested that the harvest of crocodile hatchlings and skin do not represent the actual condition since the skin recorded were only those sent outside of the province. Determining zero harvest quotas of C. porosus did not stop species harvest for domestic trade. The dominant source of C. porosus skin export was captive breeding, while C. novaeguineaewas sourced from the wild. Ranch-sourced skin of both species for export were very low.

Valuing changes in frequency of fish stock assessments

Updating stock assessments frequently and ensuring that the most recent fishery-dependent and -independent data are included is a costly endeavor. We use a management strategy evaluation for the mid-Atlantic summer flounder (Paralichthys dentatus) fishery to determine the economic returns to increasing update frequencies and decreasing the data management lag. We simulate the annual acceptable biological catch for the period 2015–2040 under a range of update frequencies and data lags. We calculate present value net economic benefits for the commercial and recreational fisheries for each scenario. Discounting, the timing of harvest quotas, species-specific price flexibilities, and fishing cost response to biomass and quota differences suggest that the benefits gained from frequent updating and reduction in data lags will vary by fishery. For summer flounder, we find the cost of more frequent updating (1 versus 5 years) and reducing the data management lag (1 versus 2 years) are more than compensated for by societal benefits generated by the fishery.

The Hardangervidda wild reindeer herd: a problematic management history

The unique and internationally important wild reindeer Rangifer tarandus herd on the Hardangervidda plateau of southern Norway has shown frequent and extreme fluctuations in harvest numbers for the past 60 years, despite considerable effort to stabilize the herd size at a winter carrying capacity of 9000 – 12 000 animals . In the absence of large mammalian predators, herd size is managed through hunting. Here we attempt to unravel the causes of the management problems related to this population by examining the relative roles of historical, biological and management-related processes. From 1900 - 1950 the population remained mainly low due to a combination of generous harvest quotas, poaching and competition from domestic reindeer. From 1950 - 2012 three extreme harvest peaks of between 4500 - 9500 animals occurred, followed by three equally extreme troughs including two shorter periods of total protection. This extreme harvest fluctuation contrasts with the estimated annual harvest of 2300 - 3000 needed to stabilize the winter herd between 9000 - 12 000 animals. We conclude that this population has been difficult to manage mainly because of 1) a management based on frequently unreliable population data on herd size (especially before 2001), 2) lack of in depth analyses and evaluation of both recruitment and sex and age composition and 3) a low and highly variable harvest success (harvest/quota) due mainly to poor hunter mobility, a disadvantage when reindeer must be harvested from large flocks that constantly move upwind, seeking refuge on small areas with few hunters. More reliable population data to create better harvest models plus increased hunter mobility are necessary to attain a more sustainable herd size, implying an improvement of the current herd survey methodology available to local reindeer boards. Finally, a critical and independent evaluation of the scientific methodology employed to study and manage this herd is needed.

Sampling selectivity in acoustic-trawl surveys of Pacific sardine (Sardinops sagax) biomass and length distribution†

Demer, D. A., Zwolinski, J. P., Cutter, G. R. Jr, Byers, K. A., Macewicz, B. J., and Hill, K. T. Sampling selectivity in acoustic-trawl surveys of Pacific sardine (Sardinops sagax) biomass and length distribution. – ICES Journal of Marine Science, 70: . To annually assess the northern stock of Pacific sardine (Sardinops sagax) in the California Current and set harvest quotas for the US fishery, managers have used an age-structured stock synthesis model fitted with results from acoustic-trawl (ATM), daily-egg-production, and aerial-photogrammetric survey methods, fishery landing and individual-length data, and many assumed or empirically derived parameters. In these assessments, sardine landed at ports spanning from Ensenada, México to Vancouver Island, Canada were assumed to be solely from the northern stock. It was also assumed that the ATM estimates of sardine biomass were negligibly biased for the sizes of fish sampled by the survey trawls (i.e., catchability q = 1 for sardine standard length (SL) values greater than ∼17 cm). Due to these catchability and length-selectivity assumptions, the ATM- and assessment-estimated abundances are mostly similar for larger sardine. However, the assessment estimates include large abundances of small sardine (SL values less than ∼15 cm) that are not represented in either the ATM-survey results or the fishery landings, and generally did not recruit to the migrating northern stock sampled by the ATM surveys. We considered four explanations for this disparity: (i) the ATM length-selectivity assumption is correct; (ii) the non-recruiting small fish may comprise a smaller portion of the stock than indicated by the assessments; (iii) during years of low recruitment success, those size classes may be virtually completely fished by the Ensenada and San Pedro fisheries; or (iv) they may belong to the southern sardine stock. This investigation emphasizes the previously identified importance of differentiating samples from the northern and southern stocks and surveying their entire domains.

Distribution, ecological attributes and trade of the New Guinea carpet python (Morelia spilota) in Indonesia

Carpet pythons (Morelia spilota) are medium-sized non-venomous snakes inhabiting most of continental Australia and a small area of New Guinea. They have been relatively well studied in Australia, but little is known about the New Guinea population, even though it is harvested and exported from Indonesia for the international pet trade. In total, 281 locality records were compiled for two distinct populations south of latitude 7°S in Papua New Guinea and the Indonesian province of Papua. Traders in Papua collected 274 carpet pythons (most of which were recently hatched neonates) for the pet trade. Data from a sample of 174 individuals revealed little sexual dimorphism in any traits, although males appear to grow larger than females despite females maturing at greater lengths. Fecundity was high (average 17 eggs) and reproduction was highly seasonal, with hatching in December and January. Harvest quotas for the province of Papua were exceeded in all years between 2000 and 2009 due to 50% of the national quota being allocated to West Papua province where this species is yet to be recorded. The present study provides distribution, trade and ecological information to inform conservation management of this species in Indonesia.

Design of aerial surveys for population estimation and the management of macropods in the Northern Tablelands of New South Wales, Australia

As part of a kangaroo management program, eastern grey kangaroos (Macropus giganteus) and common wallaroos (M. robustus robustus) are harvested from three kangaroo management zones in north-eastern New South Wales, Australia. To set sustainable harvest quotas, it is necessary to obtain reasonably accurate estimates of the sizes of the populations of these two species of macropod. Recently, this has been done on two occasions using helicopter line-transect surveys. For the most recent of these surveys, conducted in 2004, each management zone was subdivided into three strata of increasing kangaroo density and the surveys were designed in relation to this stratification using an automated survey design algorithm. The results of the surveys were that eastern grey kangaroo densities were estimated as 8.11 ± 1.81 km–2 in the Glen Innes zone, 10.23 ± 2.41 km–2 in the Armidale zone and 4.82 ± 0.87 km–2 in the Upper Hunter zone. Wallaroo densities for these three zones were 3.06 ± 0.73 km–2, 5.68 ± 3.45 km–2 and 4.40 ± 1.01 km–2 respectively. The wallaroo densities were determined by multiplying the initial estimated densities by a correction factor of 1.85. Across the three kangaroo management zones, eastern grey kangaroo densities did not change in any significant way between the two surveys. This was also the case for wallaroos in the Glen Innes and Armidale zones. Wallaroo density in the Upper Hunter zone, however, increased significantly between the two surveys. Over a decade before these surveys were conducted, a series of ground surveys using walked line-transect sampling were undertaken. The density estimates derived from the helicopter surveys proved to be broadly comparable to those derived from the ground surveys, suggesting that conducting helicopter line-transect surveys designed using the method deployed here is effective in producing population estimates for the purpose of kangaroo management.