CCAMLR

The occurrence of dwarf minke whales (Balaenoptera acutorostrata subsp.) around the Antarctic Peninsula was examined based on 406 sightings of minke whales recorded during the Chilean Antarctic Scientific Expeditions and other opportunistic cetacean surveys. Identification of the species was made only for the whales sighted in the proximity of the vessels when the specific diagnostic characters could be confirmed. Of the 406 sightings, 296 were assigned to Antarctic (519 individuals), nine (11 individuals) to dwarf and 101 to unidentified minke whales (149 individuals). Dwarf minke whales were identified by the reported external diagnostic characters for this species. Seven animals occurred around the South Shetland Island and four in the Gerlache Strait. In addition, another two animals were identified as dwarf minke whales in the Bellinghausen Sea in winter 1993, being these the most southern records for this species. These results confirm the occurrence of dwarf minke whales around the Antarctic Peninsula during the summer seasons, as well as in the Bellinghausen Sea in winter. The geographical range of these sightings was comprised between 61°03´ and 69°25´S and between 55°29´ and 86°53´W. These results also suggest that some dwarf minke whales remain in the Antarctic during the austral winter.

The West Antarctic Peninsula (WAP) and adjacent Scotia Sea support abundant wildlife populations, many of which were nearly extirpated by humans. This region is also among the fastest-warming areas on the planet, with 5–6 °C increases in mean winter air temperatures and associated decreases in winter sea-ice cover. These biological and physical perturbations have affected the ecosystem profoundly. One hypothesis guiding ecological interpretations of changes in top predator populations in this region, the “sea-ice hypothesis,” proposes that reductions in winter sea ice have led directly to declines in “ice-loving” species by decreasing their winter habitat, while populations of “ice-avoiding” species have increased. However, 30 y of field studies and recent surveys of penguins throughout the WAP and Scotia Sea demonstrate this mechanism is not controlling penguin populations; populations of both ice-loving Adélie and ice-avoiding chinstrap penguins have declined significantly. We argue in favor of an alternative, more robust hypothesis that attributes both increases and decreases in penguin populations to changes in the abundance of their main prey, Antarctic krill. Unlike many other predators in this region, Adélie and chinstrap penguins were never directly harvested by man; thus, their population trajectories track the impacts of biological and environmental changes in this ecosystem. Linking trends in penguin abundance with trends in krill biomass explains why populations of Adélie and chinstrap penguins increased after competitors (fur seals, baleen whales, and some fishes) were nearly extirpated in the 19th to mid-20th centuries and currently are decreasing in response to climate change.

The organization, example outputs, and future objectives of an integrated, age‐structured model designed to estimate krill population dynamics and productivity are described. The model's capabilities are illustrated using 19 years of survey data collected by the U.S. AMLR Program around the South Shetland Islands, but it is being developed to be applicable to any region where multi‐year data on size compositions from net tows and total biomass from hydroacoustics or net tows are available. The model estimates population parameters from data based on a joint likelihood function and is being developed in stages to incorporate different data sources. Model estimates are incremented for time of year in which the data were collected, with multiple surveys at different times within a year possible. Ages are converted to lengths based on a single age‐to‐length transition matrix. Currently the model assimilates data from research surveys but data from fisheries and eventually from krill predators and environmental time series will also be incorporated. Annual movement by krill among areas is included, but, currently, the model has convergence problems (is able to make point estimates but not variance estimates) when movement is included; converge can be achieved when movement is ignored.

One of the recommendations for future work from the 2008 Predator Survey Workshop was ‘....that alternative census methods for large (penguin) colonies may be helpful. Such methods include the use of satellite imagery and the use of GPS receivers to accurately map colony areas from which abundance could be estimated given known information on nest density within colonies...’ This paper uses virtual simulation in a GIS environment to explore how the recommended area/density approach can be optimally designed when abundance estimates are required for large colonies or over large scales. The approach is illustrated using a case study of a large-scale ground survey of Adélie penguins. The findings implications for optimising designs over much larger areas using alternate platforms such as satellites and aircraft.

The influence of the climate change on krill based Southern Ocean ecosystem is studied intensively last decade. To study the possible connections between Antarctic Peninsula regional climate warming and ecosystem changes the data of Antarctic krill density (KRILLBASE data) and of surface air temperature (READER data) were used. Decadal variability of winter temperature on the regional scale was analyzed. We apply Fourier and wavelet analysis to the averaged temperature anomaly time series and note the oscillations with 3-8 year periods and a decadal oscillation with a period of about 16 years. Preliminary analysis of Antarctic krill density variations shows about 8-year variability as well. Correlation coefficient between krill density data and temperature anomalies is small (less 0.2) however is increased significantly to 0.4 when applying 1-year data shift (krill density after anomalies occurrence). The 3-8 year periods possibly related to the ENSO variations and connected to sea ice change.

Species composition and abundance of by-catch fish were analyzed using the fish by-catch samples collected by scientific observers onboard Japanese commercial krill fishing vessels in the north of South Georgia during the austral winter from 2002 to 2008. A total of 19 species belonging to 8 families were identified in the by-catch samples, among which the 3 species, Krefftichthys anderssoni, Lepidonotothen larseni and Champsocephalus gunnari, were recorded in every year from 2002 to 2008, and also the most abundant. Different life stages of K. anderssoni, Gymnoscopelus nicholsi, C. gunnari and L. larseni from larvae to adults were found, suggesting that these species may have their nursery ground around South Georgia. The length frequency distribution of C. gunnari varied with years and may indicate the increase in size in recent years. Electrona antarctica was not a major component of the recent mesopelagic ichthyofauna. In contrast, P. choriodon, which is known as a South temperate species, became to dominate the recent samples. Additionally, the size distribution of P. choriodon was unimodal, indicating that the individuals probably migrated from the population in northern warmer areas. Since the distribution patterns and biological peculiarity of fish are related to oceanographic conditions, the shifts in species and size composition may demonstrate oceanographic and climatic changes in the Antarctic Ocean. Long-term monitoring of ichthyofauna through the scientific observer program and close examination of the biological samples would provide important information on environmental fluctuations in the Antarctic Ocean.

To investigate spatio-temporal variability of krill body length and number of bycatch fish, observer data sets on Japanese krill fishery from 1995 to 2008 were analyzed by using a hierarchical Bayesian model. The model was composed of multistage cluster units (i.e., years, subarea, vessels, and haul) based on a state-space model, which can separate biological process error in the population dynamics from observation error caused by the fishery activity and individual observation. In both krill length and bycatch fish number, the parameters estimated by MCMC showed the variation among years, subareas, and vessels. The potent interaction effect between year and subarea suggests large spatiotemporal variability of krill population structure and a difficulty in predicting krill population dynamics. Variances of krill length and bycatch fish number by sampling stages were calculated by the multistage sampling formula with the variance terms derived from the Bayesian model. For both krill length and bycatch fish number, haul coverage ranging 0–50% showed marked effects on CV, although vessel coverage hardly changed CV. The results of this study suggest that scientific data collectionby commercial fishery is an important source of information for the management of krill resources and Antarctic ecosystem, while enlarging haul coverage > 50% have smaller effects in improving data accuracy and may not balance the rising cost of observer program.

At WG-EMM-09 the Working Group noted that the photographic method used in WG-EMM-09/38 could be incorporated as a modification of CEMP Standard Method A3 (penguin breeding population size). This paper reviews aspects of Methods A3a, A3b and related A9 (breeding chronology) in the most recent version of the CEMP Standard Methods that are relevant to this proposal, outlines some difficulties in the practical application of these Methods, and proposes some general modifications to the Methods to allow greater flexibility in the collection and interpretation of penguin breeding population counts.

Cameras and other optical instruments are increasingly being used as cheap, convenient and reliable tools for surveillance and monitoring. This paper describes (1) the kinds of observations and measurements relevant to CEMP that can be obtained from an automated camera system specifically developed for use in the extreme conditions of Antarctica, (2) a preliminary assessment of the utility of cameras for measuring Adélie penguin breeding success, and (3) how cameras are currently being used to expand the spatial extent of Adélie penguin monitoring, and to extend monitoring to additional land-based breeding species, in east Antarctica.

We made a survey plan to observe krill escapement, attached an underwater video camera on a trawl net of a Japanese commercial trawler, and started observation to collect video images of krill passage through the rope and netting parts of the trawl net. Preliminary examination of video images obtained via satellite-linked transmission indicated very low incidence of krill escapement from top panels near the net opening.