Investigating opportunities to support indigenous aquaculture in Australia : Visit to Kimberley, Western Australia, May 2003

The STREAM Initiative has been working with issues relating to livelihoods, policy and institutional development and communications throughout Asia-Pacific. Recently this has included work in India with indigenous communities supporting people to have a voice in policy making processes. There appear to be some parallels between this work and the objectives of Kimberley Aquaculture Aboriginal Corporation (KAAC) and also the Agriculture Fisheries and Forestry Australia (AFFA) Indigenous Aquaculture Unit (IAU), National Aquaculture Development Strategy for Indigenous Communities in Australia. (PDF contains 13 pages)

Natural habitat and population control mechanism of Crassula helmsii (Australian Swamp Stonecrop) in Australia

The plant Crassula helmsii (Kirk) Cochayne, was likely to become widely distributed and to dominate many damp and wet areas of nature reserves, recreational waters and agricultural drainage of Britain. The aim of this report was to study Australian Swamp Stonecrop in its natural habitat where it is in balance with its environment. This contrasts with its rapid and widespread distribution in the U.K. where its growth interferes with the use of fisheries and amenity lakes but also reduces the value of nature reserves and sites of special scientific interest by suppressing native flora. It was proposed to observe its growth at a variety of sites over its natural distribution and to include some environmental factors, e.g. water-level, water-chemistry (nutrients, acidity and alkalinity), frost-tolerance, salinity, with the help of portable sensors, locally-available services or data. 8 weeks of travel in Australia allowed time to study the plant in its natural habitat including the coastal areas of the southern half of the continent i.e . Western Australia, South Australia, New South Wales, Victoria, Tasmania and southern Queensland. The overall objective was to determine the environmental range by visits to selected sites of Crassula helmsii over its geographic range.

Biological characteristics and mortality of western butterfish (Pentapodus vitta), an abundant bycatch species of prawn trawling and recreational fishing in a large subtropical embayment

The western butterfish (Pentapodus vitta) is numerous in the bycatch of prawn trawling and recreational fishing in Shark Bay, Western Australia. We have thus determined crucial aspects of its biological characteristics and the potential impact of fishing on its abundance within this large subtropical marine embayment. Although both sexes attained a maximum age of 8 years, males grow more rapidly and to a larger size. Maturity is attained at the end of the first year of life and spawning occurs between October and January. The use of a Bayesian approach to combine independent estimates for total mortality, Z, and natural mortality, M, yielded slightly higher point estimates for Z than M. This result indicates that P. vitta is lightly impacted by fishing. It is relevant that, potentially, the individuals can spawn twice before recruitment into the fishery and that 73% of recreationally caught individuals are returned live to the water.

Aspects of ecology of Owena reservoirs: implication on fish production

The article gives physical description of Owana reservoir, Nigeria. The reservoir was chemically and thermally stratified partial mixing of the water was observed during the rains. The concentration of major ions in the water showed distinct peculiarities. The captions (Na super(+), K super(+)Ca super(H),Ca super(Z), Mg super(++)) SO sub(4) super(2-) were relatively low. The water had high dissolved oxygen, it was acidic and also had low values of alkalinity, conductivity and total dissolved solids. About 61 plankton taxa belonging to 21 species were identified. The reservoir supports a commercial fishery of about fifteen fishermen with about fifteen species of fish caught daily with the aid of traps set and cast nets. Effective management of the lake will enhance fish production

Aspects of the ecology of the crustacean zooplankton in the Sanyati Basin, Lake Kariba

Investigations on the zooplankton in Lake Kariba were carried out as part of a broader programme investigating components of the sardine, Limnothrissa miodon, food chain and factors affecting their productivity. This report deals mainly with the crustacean zooplankton, Bosmina longirostris and Mesocyclops leuckarti, which are the most important species in the sardine's diet. Factors which influence the number and distribution of the zooplankton are discussed. The relationship between the zooplankton and Limnothrissa are also briefly discussed.

The western blue groper (Achoerodus gouldii), a protogynous hermaphroditic labrid with exceptional longevity, late maturity, slow growth, and both late maturation and sex change

The western blue groper (Achoerodus gouldii) is shown to be a temperate protogynous hermaphrodite, which spawns between early winter and mid-spring. Because A. gouldii changes body color at about the time of sex change, its color can be used as a proxy for sex for estimating the size and age at sex change and for estimating growth when it is not possible to use gonads for determining the sex of this fish. The following characteristics make A. gouldii highly susceptible to overfishing: 1) exceptional longevity, with a maximum age (70 years) that is by far the greatest yet estimated for a labrid; 2) slow growth for the first 15 years and little subsequent growth by females; and 3) late maturation at a large total length (TL50 = 653 mm) and old age (~17 years) and 4) late sex change at an even greater total length (TL50 = 821 mm) and age (~35 years). The TL50 at maturity and particularly at sex change exceeded the minimum legal total length (500 mm) of A. gouldii and the lengths of many recreationally and commercially caught fish. Many of these characteristics are found in certain deep-water fishes that are likewise considered susceptible to overfishing. Indeed, although fishing effort for A. gouldii in Western Australia is not particularly high, per-recruit analyses indicate that this species is already close to or fully exploited.

The History of Oyster Farming in Australia

Aboriginal Australians consumed oysters before settlement by Europeans as shown by the large number of kitchen middens along Australia's coast. Flat oysters, Ostrea angasi, were consumed in southeastern Australia, whereas both flat and Sydney rock oysters, Saccostrea glomerata, are found in kitchen middens in southern New South Wales (NSW), but only Sydney rock oysters are found in northern NSW and southern Queensland. Oyster fisheries began with the exploitation of dredge beds, for the use of oyster shell for lime production and oyster meat for consumption. These natural oyster beds were nealy all exhausted by the late 1800's, and they have not recovered. Oyster farming, one of the oldest aquaculture industries in Australia, began as the oyster fisheries declined in the late 1800's. Early attempts at farming flat oysters in Tasmania, Victoria, and South Australia, which started in the 1880's, were abandoned in the 1890's. However, a thriving Sydney rock oyster industry developed from primitive beginnings in NSW in the 1870's. Sydney rock oysters are farmed in NSW, southern Queensland, and at Albany, Western Australia (WA). Pacific oysters, Crassostrea gigas, are produced in Tasmania, South Australia, and Port Stephens, NSW. FLant oysters currently are farmed only in NSW, and there is also some small-scale harvesting of tropical species, the coarl rock or milky oyster, S. cucullata, and th black-lip oyster, Striostrea mytiloides, in northern Queensland. Despite intra- and interstate rivalries, oyster farmers are gradually realizing that they are all part of one industry, and this is reflected by the establishment of the national Australian Shellfish Quality Assuarance Program and the transfer of farming technology between states. Australia's oyster harvests have remained relatively stable since Sydney rock oyster production peaked in the mid 1970's at 13 million dozen. By the end of the 1990's this had stabilized at around 8 million dozen, and Pacific oyster production reached a total of 6.5 million dozen from Tasmania, South Australia, and Port Stephens, a total of 14.5 million dozen oysters for the whole country. This small increase in production during a time of substantial human population growth shows a smaller per capita consumption and a declining use of oysters as a "side-dish."

Quantitative determination of the timing of otolith ring formation from marginal increments in four marine teleost species from northwestern Australia

The sectioned otoliths of four fish species from a tropical demersal trawl fishery in Western Australia revealed a series of alternating trans-lucent and opaque zones in reflected light. The translucent zones, referred to as growth rings, were counted to determine fish ages. The width of the opaque zone on the periphery of the otolith section as a proportion of the width of the previous opaque zone (index of completion) was used to determine the periodicity of growth-ring formation. This article describes a method for modeling changes in the index of ring completion over time, from which a parameter for the most probable time of growth-ring formation (with confidence intervals) can be determined. The parameter estimate for the timing of new growth-ring formation for Lethrinus sp. 3 was from mid July to mid September, for Lutjanus vitta from early July to the end of August, for Nemipterus furcosus from mid July to late September, and for Lutjanus sebae from mid July to mid November. The confidence intervals for the timing of formation of growth rings was variable between species, being smallest for L. vitta, and variable between fish of the same species with different numbers of growth rings. The stock assessments of these commercially important species relies on aging information for all the age classes used in the assessment. This study demonstrated that growth rings on sectioned otoliths were laid down annually, irrespective of the number of growth rings, and also demonstrated that the timing of ring formation for these tropical species can be determined quantitatively (with confidence intervals.

Aspects principaux des variations du phytoplancton sur le plateau continental ivorien

21 surveys over the whole Ivorian continental shelf lead to a description of the phytoplankton repartition according to the different seasons: great and small cold seasons, discharge seasons, and warm seasons. Yearly means of surface cells concentrations range from 1000 to 30000 cells per liter, corresponding to a daily production of 386 to 1166 mg C/m2, according to regression analysis. These values make Côte d'Ivoire a rather rich region, which is subjected to wide standing crop variations.

A sudden collapse in distribution of Pacific sardine (Sardinops sagax) off southwestern Australia enables an objective re-assessment of biomass estimates

Fishery-independent estimates of spawning biomass (BSP) of the Pacific sardine (Sardinops sagax) on the south and lower west coasts of Western Australia (WA) were obtained periodically between 1991 and 1999 by using the daily egg production method (DEPM). Ichthyoplankton data collected during these surveys, specifically the presence or absence of S. sagax eggs, were used to investigate trends in the spawning area of S. sagax within each of four regions. The expectation was that trends in BSP and spawning area were positively related. With the DEPM model, estimates of BSP will change proportionally with spawning area if all other variables remain constant. The proportion of positive stations (PPS), i.e., stations with nonzero egg counts — an objective estimator of spawning area — was high for all south coast regions during the early 1990s (a period when the estimated BSP was also high) and then decreased after the mid-1990s. There was a decrease in PPS from the mid-1990s to 1999. The particularly low estimates in 1999 followed a severe epidemic mass mortality of S. sagax throughout their range across southern Australia. Deviations from the expected relationship between BSP and PPS were used to identify uncertainty around estimates of BSP. Because estimation of spawning area is subject to less sampling bias than estimation of BSP, the deviation in the relation between the two provides an objective basis for adjusting some estimates of the latter. Such an approach is particularly useful for fisheries management purposes when sampling problems are suspected to be present. The analysis of PPS undertaken from the same set of samples from which the DEPM estimate is derived will help provide information for stock assessments and for the management of purse-seine fisheries.

Factors influencing the timing and frequency of spawning and fecundity of the goldlined seabream (Rhabdosargus sarba) (Sparidae) in the lower reaches of an estuary

We have studied the reproductive biology of the goldlined seabream (Rhabdosargus sarba) in the lower Swan River Estuary in Western Australia, focusing particularly on elucidating the factors influencing the duration, timing, and frequency of spawning and on determining potential annual fecundity. Our results demonstrate that 1) Rhabdosargus sarba has indeterminate fecundity, 2) oocyte hydration commences soon after dusk (ca. 18:30 h) and is complete by ca. 01:30−04:30 h and 3) fish with ovaries containing migratory nucleus oocytes, hydrated oocytes, or postovulatory follicles were caught between July and November. However, in July and August, their prevalence was low, whereas that of fish with ovaries containing substantial numbers of atretic yolk granule oocytes was high. Thus, spawning activity did not start to peak until September (early spring), when salinities were rising markedly from their winter minima. The prevalence of spawning was positively correlated with tidal height and was greatest on days when the tide changed from flood to ebb at ca. 06:00 h, i.e., just after spawning had ceased. Because our estimate of the average daily prevalence of spawning by females during the spawning season (July to November) was 36.5%, individual females were estimated to spawn, on average, at intervals of about 2.7 days and thus about 45 times during that period. Therefore, because female R. sarba with total lengths of 180, 220, and 260 mm were estimated to have batch fecundities of about 4500, 7700, and 12,400 eggs, respectively, they had potential annual fecundities of about 204,300, 346,100 and 557,500 eggs, respectively. Because spawning occurs just prior to strong ebb tides, the eggs of R. sarba are likely to be transported out of the estuary into coastal waters where salinities remain at ca. 35‰. Such downstream transport would account for the fact that, although R. sarba exhibits substantial spawning activity in the lower Swan River Estuary, few of its early juveniles are recruited into the nearshore shallow waters of this estuary.

A Low-level Geographic Information System for coastal zone management, with applications to Brunei Darussalam: Part I: The concept and its design elements

This contribution is the first part of a four-part series documenting the development of B:RUN, a software program which reads data for common spreadsheets and presents them as low-resolution maps of slates and processes. The program emerged from a need which arose during a project in Brunei Darussalam for a 'low level' approach for researchers to communicate findings as efficiently and expeditiously as possible. Part I provides a overview of the concept and design elements of B:RUN. Part II will highlight results of the economics components of the program evaluating different fishing regimes, sailing distances from ports and fleet operating costs. Environmental aspects will be presented in Part III in the form of overlay maps. Part IV will summarize the implications of B:RUN results to coastal and fishery resources management in Brunei Darussalam and show how this approach can be adapted to other coastlines and used as a teaching and training tool. The following three parts will be published in future editions of Naga, the ICLARM Quarterly. The program is available through ICLARM.

Catches of Humpback Whales, Megaptera novaeangliae, by the Soviet Union and Other Nations in the Southern Ocean, 1947–1973

From 1947 to 1973, the U.S.S.R. conducted a huge campaign of illegal whaling worldwide. We review Soviet catches of humpback whales, Megaptera novaeangliae, in the Southern Ocean during this period, with an emphasis on the International Whaling Commission’s Antarctic Management Areas IV, V, and VI (the principal regions of illegal Soviet whaling on this species, south of Australia and western Oceania). Where possible, we summarize legal and illegal Soviet catches by year, Management Area, and factory fleet, and also include information on takes by other nations. Soviet humpback catches between 1947 and 1973 totaled 48,702 and break down as follows: 649 (Area I), 1,412 (Area II), 921 (Area III), 8,779 (Area IV), 22,569 (Area V), and 7,195 (Area VI), with 7,177 catches not currently assignable to area. In all, at least 72,542 humpback whales were killed by all operations (Soviet plus other nations) after World War II in Areas IV (27,201), V (38,146), and VI (7,195). More than one-third of these (25,474 whales, of which 25,192 came from Areas V and VI) were taken in just two seasons, 1959–60 and 1960–61. The impact of these takes, and of those from Area IV in the late 1950’s, is evident in the sometimes dramatic declines in catches at shore stations in Australia, New Zealand, and at Norfolk Island. When compared to recent estimates of abundance and initial population size, the large removals from Areas IV and V indicate that the populations in these regions remain well below pre-exploitation levels despite reported strong growth rates off eastern and western Australia. Populations in many areas of Oceania continue to be small, indicating that the catches from Area VI and eastern Area V had long-term impacts on recovery.

Small-scale aquaculture for rural livelihoods: Proceedings of the Symposium on Small-scale aquaculture for increasing resilience of Rural Livelihoods in Nepal. 5-6 Feb 2009. Kathmandu, Nepal

Over the years, aquaculture has developed as one of the fastest growing food production sectors in Nepal. However, local fish supplies have been extremely inadequate to meet the ever increasing demand in the country. Nepal imports substantial quantities of fish and fish products from India, Bangladesh, Thailand, and elsewhere. Integration of pond aquaculture in existing crop-livestock-based farming system is believed to be effective in increasing local fish supply and diversifying livelihood options of a large number of small-holder farmers in southern plains (terai) and mid-hill valleys, thereby also increasing resilience of rural livelihoods. There is growing appreciation of the role of small-scale aquaculture in household food and nutrition security, income generation, and empowerment of women and marginalized communities. This book includes a total of 25 papers presented at the ‘Symposium on Small-scale Aquaculture for Increasing Resilience of Rural Livelihoods in Nepal’, held in Kathmandu on 5-6 February 2009. The papers cover technological, social, economic and environmental aspects of small-scale aquaculture development emerged from research and development initiatives of governmental, non-governmental and international research organizations in recent decad