CCAMLR

Fish Heaven is a simple spatially explicit age structured fish model, containing the basic features of standard fish modeling with a number of optional extras. It was designed within an object oriented framework to allow for the possible extension in a number of directions. In particular it was designed with the view of testing the efficacy of different statistical sampling regimes given various plausible spatial structures of fish stock.
The model has a simple age and space structured population governed by the normal life history parameters and subject to both environmental stochasticity (if desired) as well as demographic stochasticity. It is a spatially explicit model in which fish will tend to distribute themselves according to their density and the underlying habitat quality variable. On top of this, fishing occurs. This includes a wide range of fishing options. The software has been constructed to allow for it to be extended to include more complex fishing management practices.
The manual for the software, Fish Heaven Version 1.0.0, forms the body of the paper. Although Version 1.0.0 of the software is complete it is still seen as a piece of software in development. Currently the software is designed to allow environmental simulations with fishing while capturing various statistics about the status of the system. Analysis of the output must be done with a separate piece of software, such as a statistical package, reading in the output files of Fish Heaven. A number of extensions are planned for the software and these are described in the appropriate sections of the manual as 'further improvements'.
The manual and software are both contained in the file FishHeav.zip. This is on the CD of Australian Antarctic Division software and additional copies are available from the Australian Antarctic Division. The manual contains colour pictures, although black and white copies of the manual still contain all of the necessary information. The copy of the manual in FishHeav.zip is a pdf file and includes all the coloured pictures.
The executable has been compiled for Windows NT but should run on any 32bit Windows operating system. It requires no additional libraries to run and takes up less that 1.4M of disk space. When running the size of the spatial grid is the limiting factor on memory requirements but is not terribly restrictive.

A brief description of hawl-by-hawl data sets from Ukrainian commercial vessels fishing tooth-fish in Subdivision 48.3 during 1986-199 1 is presented. The fishery was mainly carried out in summer months off the eastern South Georgia and at Shag Rocks. The length frequency modes amounted to 95-100 cm, which exceeded modes for the latest years of fishery. Using the generalized additive model the catch per effort estimates for 1986-99 were standardize. The fishery efficiency in 1986-95 was approximately similar, while in 1996-99 it decreased sharply. It is shown that significance of such factors as a month and depth is low, and a modified model developed without these factors consideration provides more accurate estimates.

Biostatistic data obtained by Soviet research and commercial vessels in 1970 to 1991 have been used to study length-age composition of Champsocephalus gunnari from different locations of South Georgia Island Subarea. An analysis of Ch.gunnari length-age groups spatial distribution over Eastern, Northern, Western, Southern Island Shelf and near Shag Rocks allowed for revealing similarity of Ch.gunnari length-age composition structure at early years of life for fish inhabiting areas to the south of Island and near Shag Rocks and finding a difference between those two groups and the eastern group. Larger number of "mature" fish in the west is related to migration from eastern area of maturing individuals as they grow. It has been defined that a part of western group of fish at the age of 2-3 years had been migrating towards the Shag Rocks. It has been found that predomination of recruitment over remaining fish had been characteristic of the whole population irrespective to absence or presence of fishery. It is obviously a natural character of the population under consideration. Ch.gunnari could rapidly set up and restore high abundance in Subarea just owing to that character in conjunction with pelagization of species, earlier age of sexual maturity as compared to notothenia and favourable oceanographic conditions.

An attempt has been made to study icefish as an object of acoustic survey basing on the acoustic and biological data obtained by Russian RN ATLANTIDA in the area of South Georgia Island (January-February 2000). Estimation of possible target strength values was made by a comparison to TS of other fish species having similar body structure and morphological characters, as well as taking into acount chemical and physical body properties. There has been proved a comparability of Ch.gunnari length frequencies obtained from the catches by midwater trawl to those estimated with TS in situ measurements for fish recorded within the pelagic zone. Basing on the analysis of acoustic measurements and results of commercial fleet operation, there has been showed availability within the pelagic zone by daytime of Ch.gunnari, biomass of which would be out of bottom trawl survey access. It has been indicated that one of directions of improving Ch.gunnari stock state estimation could be an application of acoustic method to evaluate biomass distributed within the pelagic zone. The latter rises the problem of carrying out acoustic trawl survey to estimate Ch.gunnari biomass and distribution of species pelagic and pre-bottom concentrations.

This paper summarises seabird bycatch during the fourth year (July 1999-June 2000) of sanctioned longline fishing for Patagonian toothfish Dissostichus eleginoides in the Exclusive Economic Zone around South Africa's Prince Edward Islands. Data were obtained from fishery observers aboard all 11 sanctioned fishing trips. Fishing effort was 7.4 million hooks, a 45% increase on the number of hooks set in 1998199. Observers reported 268 birds of six species killed. White-chinned Petrels Procellaria aequinoctialis predominated (92.2%), followed by Eastern Yellow-nosed Mollymawks Thalassarche [chlororhynchos] bassi (3.5%), Grey Pretrels P. cinerea (l.8%), Grey-headed Mollymawks Thalassarche chrysostoma (1.5%) and giant petrels Macronectes spp. (1.1%). Average seabird bycatch rate by sanctioned vessels was 0.036 birds per 1 000 hooks, more than double that reported in 1998/99, but still considerably less than that reported in either 1996/97 or 1997/98. The absolute number of birds killed increased more than threefold compared to 1998/99 due to the marked increase in fishing effort.
Variance in bird bycatch rates among trips ranged from 0.000 to 0.142 birds killed per 1 000 hooks. Birds were killed on 7.7% of sets, with most (68%) birds killed on only 49 sets that had multiple casualties (2.8% of sets). As in previous years, much of the variance could be explained in terms of fishing season (higher bycatch rate in summer), time of setting (higher during the day), and distance from the Prince Edward Islands (higher within 200 km of the islands).

We tested the efficacy of a Mustad underwater setting funnel to reduce seabird bycatch in a demersal longline fishery for Patagonian toothfish Dissostichus eleginoides. The funnel, which deploys the longline 1-2 m beneath the sea surface, was used on 52% of 1714 sets (total effort 5.12 million hooks) over a two-year period. There was no evidence for lower catches or significantly higher bait loss on sets through the funnel. Overall bird bycatch rate was low (0.022 birds per 1000 hooks), and was dominated by White-chinned Petrels Procellaria aequinoctialis (88% of the 114 birds killed). Bycatch rate was three times lower when the funnel was used both by day and at night. Daytime catch rates with the funnel were less than those attained during night sets without the funnel. Underwater setting offers a significant reduction in seabird mortality and could increase fishing efficiency by allowing daytime setting. However, small numbers of albatrosses were caught during daytime sets with the funnel, and its use for daytime sets should be closely monitored.

Historical information is assessed on the distribution of spawning and larval mackerel icefish within subarea 48.3 (South Georgia). This is considered alongside other new data from commercial fisheries and research surveys. It is concluded that there is strong evidence for inshore spawning during April within and close to the bays on the north side of the island. Some spawning at much lower intensity almost certainly occurs over much of the shelf although the intensity appears to be small in comparison with inshore spawning. There is some evidence for spawning at Shag Rocks although the precise location is unknown and there are indications that there may be a second limited spawning season in October although the evidence is weak.