CCAMLR

This report presents the results of the second workshop for identifying Marine Protected Areas (MPAs) in Domain 1 of CCAMLR. The results of the first Workshop were presented in WG-EMM-12/69.

This second workshop was organized as bilateral meeting between Chile and Argentina in order to review the progress achieved since the first international workshop held at Valparaíso in 2012. The list of assistants is provided in Annex 1. The workshop was held at La Serena, Chile, between 2-4 September 2013.

We compare the diet and the foraging distribution of Adélie penguins at Hope Bay/Esperanza, during the late part of the breeding season and their subsequent post breeding dispersal in two consecutive years. We also compare data from the krill fishery to describe Adélie penguin foraging areas with krill fishery activity at spatial and temporal scale.

During both seasons, the bulk of the diet was represented by krill. Foraging locations during the breeding period were concentrated to the west of the colony and in the northern Bransfield Strait/Mar de la Flota in both years. During the pre-moulting period, Adélie penguins dispersed away from the colony and foraged further to the east in the northern Weddell Sea up to 400 km from the colony. During the breeding period of 2013, Adélie foraging areas and fishery activity showed an overlap in both temporal and spatial scale; no such direct overlap was apparent during the following season.

Our results showed that foraging areas during breeding and postbreeding dispersal are consistent across years, suggesting that the Bransfield - Weddell shift region is an important feeding area for Adélie penguins breeding in the tip of the Antarctic Peninsula.

More than 100 research SCUBA-dives to depths till 60 meters (2003-2004), and more than 40 research SCUBA-dives to depth till 50 meters (2011-2012) was provided. During the summer season of the 19th Ukrainian Antarctic expedition in 2014 twenty research SCUBA-dives were carried out during which a survey of the two already proposed MPAs was provided. For a further development of Marine Protected Area Network it is necessary for each area to establish a category in accordance with the procedure IUCN. Planned to research two areas: “Stella Creek” and “Skua Creek”.

Understanding the relative contributions of different sources of mortality and survival in predator populations can improve ecosystem models and management of marine ecosystems.  Within the Antarctic bottom-up processes are widely cited for explaining penguin population declines, whereas for Antarctic fur seals, top-down processes are most cited as the primary driver for declining pup production.  This has led to an under emphasis of the role of bottom-up drivers for controlling fur seal production within the system.  We review the historical data in Antarctic pup production and provide annual pup production estimates from 2002-2012 for Cape Shirreff, Livingston Island.  Age-specific natality rates are provided as an indicator of bottom-up drivers and we contrast these with early season neonate mortality and leopard seal predation rates.  Fur seal pup production has undergone a dramatic declines in the last decade (12.1% per annum since 2002).  Since 1998, natality rate has also declined 14%, largely driven by poor recruitment and an aging population.  However, age-specific natality rate has also declined.  Predation rate has increased 4% per year since 2002.  We discuss the relative roles of bottom-up and top-down contributions to the decline in fur seals.      

Research during the last decade has revealed much about the early life history of Pleuragramm antarcticum, including confirmation of the first known nursery ground in Terra Nova Bay. However, there is still much unknown about larval fish distribution in the Ross Sea, Antarctica. During a United States National Science Foundation research cruise in the late austral summer 2013, we opportunistically sampled the icthyoplankton community at 17 locations in the western Ross Sea as well as one location in the central Ross Sea and one location in the far south of the eastern Ross Sea (in the Bay of Whales). Larval P. antarcticum made up more than 99% of the icthyoplankton in the western Ross Sea. Most of these fish had hatched during the current season. Length data from these fish obtained over the course of the cruise supports growth rates and hatching times consistent with reported hatching events in Terra Nova Bay. The most numerous abundances (3400+ in each tow) of larval P. antarcticum were found along the ice margin in the western Ross Sea, further suggesting the importance of sea ice to this species. Finally, a unique tow in the Bay of Whales revealed recently hatched P. antarcticum in mid-March, suggesting the presence of a potential eastern Ross Sea nursery ground. This late hatching period may be explained by latitudinal, climatic and oceanographic variations in this region.  

Three different trawls were used to sample Antarctic krill for the determination of demographic and abundance patterns around the South Shetland Islands during Austral summer 2014. A 60cm BONGO net (333 and 505 µm mesh), a 1.8m IKMT (505 µm mesh); and a pelagic ENGEL trawl (594m² mouth area, 10mm cod end liner) were used and their selectivities are compared. Despite very different apparent selectivities, length frequency distributions were generally similar. Median lengths based upon Empirical Distribution Functions (EDFs) for the three gears varied over about 7mm, with the BONGO net catching the largest range of krill (15mm to 60mm), while the ENGEL trawl captured the narrowest (27 to 61), and the size was shifted to larger animals. These differences suggest that tradeoffs between gear size and number of tows should be considered when designing fishery based sampling to augment research surveys using fishing vessels if research gear cannot be accommodated. The patterns of krill length frequency showed that krill collected in Bransfield Strait and Elephant Island areas of the South Shetlands in summer 2014 were about 42 mm in length (3yrs old), and few small (<25mm) krill (1 year old) were captured. The majority of krill were mature and in spawning condition.

As requested by CM 21-03, Annex 21-03/A, attached are the net diagrams and mammal exclusion devices included in the krill fishery notification submitted by China

Progressing from Stage 1 to Stage 2 of a feedback management strategy requires a better understanding of spatial overlap between predators and fishing activity. We provide estimates of the spatial overlap in Area 48, with particular emphasis on Subarea 48.1. We used habitat utilization data for penguins (Adélie, chinstrap, and gentoo) and pinnipeds (Antarctic fur seals, Weddell seals, and leopard seals) based on data from satellite and light-based geolocation tracking studies.  Catch data were restricted to the last 5 years, since this time period emphasizes the shift toward autumn and winter fishing in Subarea 48.1. In general, overlap of summer and winter foraging habitats with krill catches in Subarea 48.1 was observed for all predators. Overlap was highest for predators that used coastal SSMUs during the winter period, especially in the Bransfield Strait. Across years, predator distributions appeared to be more stationary and did not respond as rapidly (or on as large a scale) to conditions that might affect the distribution of fishing effort.  A comparison of CEMP parameters from two years with large differences in total catch in Subarea 48.1 suggests plausible local impacts on gentoo penguin recruitment and reproductive investment. We note that such impacts arose when CM-51-07 was invoked to close the fishery and that 55% (85,000 tonnes) of the allocation to Subarea 48.1 (155,000 tonnes) was taken from a single SSMU. We propose that 85,000 tonnes, based on observed overlap and likely impacts of such concentrated catch on predators, represents a useful upper limit for subdivision of catch among SSMUs and that a Subarea limit of 155,000 tonnes provides a catch consistent with the objectives of Article II of the Convention.

This is a companion paper to Kinzey et al. (2014), who extended the integrated stock-assessment framework for Antarctic krill (Euphausia superba) to assimilate multiple sources of survey data and estimate krill growth.  Kinzey et al. (2014) fitted stock-assessment models to survey data that were pooled at annual, seasonal, and monthly time scales.  The data were from research cruises conducted by Germany (RMT8 net samples from 1981 to 1989), the U.S. AMLR Program (IKMT net samples from 1992 to 2013 and acoustic biomass estimates from 1996 to 2011) and Peru (IKMT samples from 2014).  Results from three of the models provide a robust picture of changes in the krill population.  An annual model fitted to IKMT data collected during the austral summer and another annual model fitted to data from all surveys estimated similar absolute biomasses and changes in biomass.  A seasonal model estimated similar changes in biomass but lower absolute biomasses than the two annual models.  A monthly model estimated different changes in biomass but predicted absolute biomasses that were similar to those from the seasonal model.  All four models fitted the observed data reasonably well, but the monthly model failed basic simulation testing.  Together, results from the two annual models and the seasonal model suggest that inter-annual variations in cohort strength have dominated krill dynamics in Subarea 48.1.  Long-term trends (either decreasing or increasing) in krill biomass have not been apparent over the past 30+ years.  Differences in scaling of biomass estimates between the annual models and the more highly resolved models suggest substantial uncertainty in absolute abundance.  Management strategies that are based on absolute estimates of biomass (rather than relative estimates of biomass) may therefore be biased, possibly leading to harvests that are inconsistent with the objectives of the Convention.  We propose that WG-EMM consider how the integrated assessment framework can be used to provide management advice for the krill fishery.

In accordance with CM 21-03, Annex 21-03 A, attached are the net diagrams and mammal exclusion device diagrams referred to in the krill fishery notifications for 2014/15 submitted for the three Norwegian vessels (Juvel, Saga Sea and Antarctic Sea).