CCAMLR

Somatic growth of pelagic invertebrates is controlled by temperature and food, both of which vary in space and time. Because species specific responses in growth rates to environmental variability may affect populations through changes in reproductive potential, measuring spatial and temporal variability in growth rates of highly abundant zooplankton is critical to predict the impact of climate change on pelagic ecosystems.  Here, we used length frequencies from bi-annual surveys conducted one month apart to estimate growth rates of one the most euphausiids in the Southern Ocean, Thysanoessa macrura. We analyzed data from four separate years (1995, 1998, 2001, 2004) that varied widely in temperature and primary production. Stations within the surveys were grouped by water mass (warm Antarctic Circumpolar Current (ACC) water and cold Weddell Sea water) to assess spatial and inter-annual variability in growth. Growth rates of T. macrura varied between years and water masses, ranging from -0.037 mm day^-1 in Weddell Sea water in 2004 to 0.081 mm day^-1 in ACC water in 1995. Growth rates were higher in ACC water than in Weddell Sea water during all years. Growth rates were strongly correlated with temperature but were not significantly correlated with chl-a concentration. These results suggest that the growth rates of T. macrura may increase in regions exhibiting warming trends, such as the Antarctic Peninsula. This contrasts with published data on the growth rates of Euphausia superba, which is predicted to be impacted negatively by climate warming.

We conducted a whole-colony census of the Adélie penguin colony at Esperanza/ Hope Bay. We also update breeding population data for selected breeding groups recorded consistently from 1995/96 to 2012/13. Both the whole colony and the selected breeding groups exhibit population declines, similar to what has been observed in other colonies throughout the WAP. The assessment of this population will contribute to the estimate of total predator biomass in Area 48.

A first estimation of the ρ conversion factor for the flow meter, used for converting volume into green weight, is provided.

Uncertainty related to estimates of krill green weight from catches has recently been an issue raised repeatedly within CCAMLR for a number of years, resulting in a modification to the C1 form implemented for the fleet in 2012. There are at present three Norwegian vessels operating in the krill fishery for Euphausia superba in the Antarctic. These vessels have in recent years contributed to 50-60 % of the total krill harvest, and reliable uncertainty estimates from these vessels will therefore be important contributions to an estimate of total uncertainty in catch weight. Here, we present the procedures for uncertainty estimation on board the Norwegian vessels, including how measurements are carried out in practice and transferred to the C1 forms. We also present a brief evaluation of results and procedures.

The US AMLR Program has established a 5 year winter oceanographic and biological sampling program to better understand winter conditions affecting the productivity and survival of euphausiids in a changing ecosystem. Oceanographic sampling includes hydrographic measurements as well as collection and analysis of water samples from fixed depths. Net tows for euphausiids and other pelagic zooplankton taxa are also collected. Here we present preliminary results  of a first 8 day shakedown cruise reporting the distribution, size and properties of krill and other euphausiids and present some data on water column properties. Future years will include more detailed sampling using a multi-net tucker trawl, ice cores for examination of ice properties, and continued development of genomic studies to understand links between pico-plankton and meso-zooplankton.

The level of observer coverage in the krill fishery and  the  scientific sampling undertaken are summarised.  During 2012 all 12 of the vessels that participated in the krill fishery carried observers for some or all of their fishing operations. From a total of 860 vessel days of fishing in 2012 observations of krill length measurements were collected on 375 ‘days’ and fish bycatch was measured on 554 ‘days’. Krill length-frequency distributions showed that the greatest variability in size structure occurred  in subarea 48.1 during 2012 when fishing occurred both in Bransfield Strait and to the west of the South Shetland Islands.  The 4901 fish measurements from 34 taxa  indicate the vast majority of fish caught as bycatch are <5cm in length.

In 2011/12, 12 vessels from five Members fished for krill in Area 48 and the total catch of krill was 161085 t (Subarea 48.1: 75630 t; Subarea 48.2: 29040 t; Subarea 48.3: 56415 t). The largest catch of krill by small-scale management unit was taken in ‘South Georgia East’ in Subarea 48.3 with a total catch of 50218 t.

So far this season (2012/13), 11 vessels from Chile, China, Korea, Norway and Ukraine have fished for krill in Area 48. The total catch reported to the end of May 2013 was 151161 t, 86% of which was taken from Subarea 48.1. At the time of preparing this report, the cumulative catch in Subarea 48.1 was 146474 t (94% of catch limit 155000 t) and that subarea was closed on 14 June 2013.

Six Members (19 vessels) submitted notifications to fish for krill in Subareas 48.1, 48.2, 48.3 and 48.4 in 2013/14. The total notified, expected level of krill catches is 545000 t. There were no notifications for exploratory fisheries for krill.