CCAMLR

Data on length and gonad-weight distribution, maturity and gonadosomatic index (GSI) of Antarctic toothfish Dissostichus mawsoni were collected from Subarea 88.1 on board of the longliner “Yantar” under Russian flag in the 2005/06 season.
Our supposition is that the predominant part of Antarctic toothfish population observed in SSRU –H, K, L in December 2005 – February 2006 will not be ready for participation in spawning of the current year. Ovaries of the most females weighed less than 2.0 kg; average GSI value of all the females examined did not exceed 2.0%.

The description of a design of longline of the "spanish type" on European hake (Merluccius merluccius) fishery in the coastal and deep waters of the North Atlantic and its modifications used on fishery of Antarctic toothfish (D. mawsoni) and Patagonian toothfish (D. eleginoides) in waters of the Antarctic Region is given. The operational experience by the longline of the «spanish type» by two vessels under the Russian flag ("Yantar" and "Volna") in Antarctic waters (seasons 2004/05-2005/06) is described.

Information on CCAMLR fisheries of relevance to the work of WG-FSA is summarised, and where possible, in a format suitable for importing directly to the Fishery Reports. Additional fishery-related information can be found in WG-FSA-06/36, 06/37, 06/38 (summaries of observer data), SC-CAMLR-XXV/BG/1 rev.1 (catches in the Convention Area) CCAMLR-XXV/16 (summary of notification for new and exploratory fisheries), WG-FSA-06/11 (estimates of IUU catches) and CCAMLR-XXV/BG/3 (implementation of conservation measures).

Life-history theory predicts that adults of long-lived species such as seabirds should optimally balance investment in current and future offspring. However, when trying to optimize investment in offspring provisioning, the most energetically costly component of seabird parental care, adults need to contend with large interannual fluctuations in prey availability and hence the cost of chick provisioning. Adults faced with this uncertainty can mechanistically balance parental care by adopting a strategy somewhere along the continuum between maintaining constant investment in foraging effort between years and letting chick provisioning fluctuate or holding chick provisioning constant and varying investment in foraging effort. Using ship-based hydroacoustic assessment of prey, time-depth recorders attached to penguins and land-based observations at the breeding colony, we examined how foraging and reproductive effort in breeding chinstrap penguins Pygoscelis antarctica responded to interannual variation in the abundance of Antarctic krill Euphausia superba in the vicinity of Seal Island, South Shetland Islands, 1990–1992. Regional measures of krill density varied by a factor of 2.5 (47.0, 23.8 and 61.2 gm–2 in 1990, 1991 and 1992, respectively) and was correlated with annual measures of breeding adult body weight and reproductive performance (breeding population size, duration of chick rearing, chick growth, breeding success and fledgling weight). In contrast, measures of penguin foraging effort (dive depth, dive duration, number of trips day–1, trip duration, number of dives trip–1 and dive rate) did not differ between years. We conclude that chinstrap penguins reduce reproductive success rather than increase foraging effort in response to decreases in prey abundance in a manner consistent with predictions of life-history strategies for long-lived seabirds.