Local knowledge surveys with small-scale fishers indicate challenges to sawfish conservation in southern Papua New Guinea     

Michael I. Grant  William T. White  Yolarnie Amepou  Leontine Baje  Amy Diedrich  Dotty Ibana  Dick J. Jogo  Stanley Jogo  Peter M. Kyne  Owen Li  Ralph Mana  Nigel Mapmani  Anthony Nagul  Darcy Roeger  Colin A. Simpfendorfer  Andrew Chin 《水产资源保护:海洋与淡水生态系统》2021,31(10):2883-2900

1. Sawfish (Pristidae) are considered to be among the most threatened families of elasmobranch (sharks and rays). There is a need to gather information on the status of poorly known sawfish populations to assist in global recovery initiatives.
2. This study used interviews with local fishers to investigate the presence of sawfish in southern Papua New Guinea (PNG) and their interactions with and uses and values for small-scale fishers.
3. A range of sawfish size classes are still encountered throughout southern PNG, while juvenile largetooth sawfish Pristis pristis were additionally reported in the freshwater reaches of all rivers surveyed. Reports of large size classes in estuarine and marine environments provide an optimistic outlook that sawfish populations persist throughout southern PNG.
4. Most fishers that catch sawfish retain them for various uses including consumption and for the sale of meat, fins and occasionally rostra. Negative population trends including decreases in catch frequency and/or size classes were reported by 66% of interviewees, with the largest declines being reported in the Kikori River. The increasing technical capacity of small-scale fishers, their preference for gillnetting and the emerging market for teleost swim bladder (a high-value fishery product) present a major ongoing threat to sawfish in southern PNG. Furthermore, the tendency of fishers to kill or remove rostra from entangled sawfish results in high fishing mortality regardless of any use by the fisher.
5. This study indicates that considerable community engagement will be necessary to manifest any legislative actions or increased enforcement on international trade regulations for sawfish in PNG. This is due to traditional land and waterway ownership values throughout PNG and the local perception of sawfish as a traditional food resource rather than an animal of intrinsic biodiversity value as perceived by global conservationists. Future research should consider exploring culturally appropriate conservation initiatives that are likely to achieve engagement and participation from local fishers.

  相似文献   

Contrasting climate velocity impacts in warm and cool locations show that effects of marine warming are worse in already warmer temperate waters     

Philina A. English  Eric J. Ward  Christopher N. Rooper  Robyn E. Forrest  Luke A. Rogers  Karen L. Hunter  Andrew M. Edwards  Brendan M. Connors  Sean C. Anderson 《Fish and Fisheries》2022,23(1):239-255

Species responses to climate change are often measured at broad spatiotemporal scales, which can miss the fine-scale changes that are most relevant to conservation and fisheries management. We develop a scaleable geostatistical approach to assess how juvenile and adult fish distributions have been shaped by changes in bottom temperature and dissolved oxygen over a recent decade of warming in the northeast Pacific. Across 38 demersal fishes, biomass trends were associated negatively with warming and positively with dissolved oxygen, but when trends in both biomass and climate were converted to velocities—the speed and direction a population would have to move to maintain consistent conditions—the effect of temperature change differed depending on local conditions. In the warmest locations, warming velocities were associated with negative biotic velocities for 19 of 69 species-maturity combinations, and yet were almost always associated with stable or positive biotic velocities in the coolest locations (64 of 69). These spatially consistent biomass declines (negative biotic velocities) in the warmest locations and increases in cooler locations suggest a redistribution of species with the potential for new ecological and fisheries interactions. After controlling for temperature, the more spatially consistent effects of dissolved oxygen were often negative, suggesting a mechanism other than hypoxia avoidance—potentially changes in primary production. Our approach identifies the species and locations that are most sensitive to observed changes in the environment at any scale, thus facilitating future vulnerability assessments.  相似文献   

Aquatic insects,D. D. Williams and B. W. Feltmate,C. A. B. International,Wallingford, Oxon, 1992. xiii + 358 pp. ISBN 0 85198 782 6     

Andrew Boulton 《水产资源保护:海洋与淡水生态系统》1993,3(3):284-285

  相似文献   

Effects of Stocking Density on Growth of Tilapia nilotica Cultured in Cages in Ponds   总被引：1，自引：0，他引：1  

Antonio E.  Carro-Anzalotta Andrew S.  McGinty 《Journal of the World Aquaculture Society》1986,17(1-4):52-57

Reported maximum carrying capacities of Tilapia nilotica reared in cages are Iow ranging from 10 to 70 kg/m³. This may be related to total numbers of caged fish reared in a body of water and not simply density per cage volume. An experiment was conducted to demonstrate such effects.
Sixteen cages in a 0.77 ha pond were stocked with T. nilotica at either 250, 500, 750, or 1,000 fish/cage for a total of 12,987 fish/ha. One cage in each of four 0.13 ha ponds was stocked with either 250 or 1,000 fish/cage for a total of 1,923 or 7,692 fish/hectare, respectively. Fish were fed a 32% protein diet at equal rates for 169 days. In the 0.77 ha pond, yield per cage was positively correlated with stocking density, while individual mean weights were negatively correlated with stocking density. However, among equal densities per cage between ponds, fish in the 0.13 ha ponds gained about 26% more than in the 0.77 ha pond. An interaction of the effects of density per cage volume and per pond area may have occurred.  相似文献   

Lipid content and composition of cultured Penaeus merguiensis fed with animal food     

Andrew Clarke  J.F. Wickins 《Aquaculture (Amsterdam, Netherlands)》1980,20(1):17-27

The lipid content and composition of cultured Penaeus merguiensis were examined by lipid extraction, thin-layer chromatography and capillary gas chromatography. The lipid content, 1.99% fresh weight, was higher than in other penaeids, but not especially so. The major lipid classes were phospholipid (47% total lipid), free sterol (27%) and triacylglycerol (17%), with smaller amounts of alkyldiacylglycerol, partial glycerides and free fatty acid. The fatty acid composition was moderately unsaturated and there were no signs of the accumulation of plant fatty acids typical of prawns fed diets supplemented with seed soils. In the light of these results, and of previous feeding studies on penaeids, it is concluded that animal lipid is probably an essential component in the diet of P. merguiensis, enabling it to maintain a normal lipid class and fatty acid composition.  相似文献   

Quantifying stem growth loss at the tree-level in a Pinus radiata plantation to repeated attack by the aphid, Essigella californica     

Alieta Eyles  Andrew P. RobinsonDavid Smith  Angus CarnegieIan Smith  Christine StoneCaroline Mohammed 《Forest Ecology and Management》2011,261(1):120-127

Since its detection in 1998, the exotic aphid pest, Essigella californica Essig (Hemiptera: Aphididae) has caused extensive defoliation in commercial Pinus radiata plantations throughout Australia. A total of one hundred and twenty plots encompassing thirty tree ages, and three thinning treatments were established in September 2006 in southern New South Wales, Australia to assess crown health and tree growth. Assessments were carried out annually during 2006-2009 to quantify the relationship between natural aphid-induced defoliation and growth loss at the individual tree level. Over the course of the four years, particularly in 2006, trees were subjected to moisture stress, as indicated by average annual rainfalls that were below the long-term average. In general, the diameter growth of individual trees appeared unaffected by crown damage severity across most tree ages, indicating that the productivity in Green Hills was limited by the interactive effects of climatic and biotic stressors (both cause premature loss of foliage). Furthermore, the results from this four-year experiment demonstrated that both moisture stress and aphid-induced defoliation constrained the growth response to thinning. However, thinning may have assisted damaged trees to maintain growth rates similar to trees with little or no damage. Understanding the impact of disturbances such as insect pest outbreaks on growth yield models is critical for optimal modelling of long-term plantation growth and management. Our results highlight the difficulty in quantifying the effect of aphid-induced defoliation when combined with chronic moisture stress.  相似文献   

Selected physical and chemical properties of mechanically extracted neem seed oil sourced as a preservative for ligno-cellulose in southwestern Nigeria     

Andrew A. ERAKHRUMEN 《中国林学(英文版)》2011,13(4):263-269

Most of the seeds produced by neem (Azadirachta indica A. Juss) trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information concerning many of the seed oils from this country, especially where it concerns the potential applications of these oils as preservatives for ligno-cellulose against bio-deterioration. Using standard procedures therefore, this study was carried out to evaluate and document selected physical and chemical properties of neem seed oil (NSO), mechanically extracted using a cold press at 31.03 N·mm -2 pressure and a room temperature of 25 ± 2℃. The results show that oil yield was 38.42% with a specific gravity of 0.91 ± 0.01. The amount of acid was 18.24 ± 1.31 mg KOH·g -1 and that of iodine 93.12 ± 2.01 g·100 g -1 , while saponification and peroxide values were 172.88 ± 2.06 and 1.42 ± 0.04 mg·g -1 respectively. The implication of the values obtained, particularly those for the chemical properties, as they concern the potential application of NSO as a preservative for ligno-cellulose, is likely that it may be useful in this regard since the values may support some of the documented anti-microbial properties of the oil, although other physical and chemical properties that may affect this potential are recommended for investigations. Conclusions and other recommendations follow in line with the results of the study.  相似文献   

Two-year dynamics of foliage labelling in 8-year-old <Emphasis Type="Italic">Pinus pinaster</Emphasis> trees with <Superscript>15</Superscript>N, <Superscript>26</Superscript>Mg and <Superscript>42</Superscript>Ca—simulation of Ca transport in xylem using an upscaling approach     

Laurent Augusto  Bernd Zeller  Andrew J. Midwood  Christopher Swanston  Etienne Dambrine  André Schneider  Alexandre Bosc 《Annals of Forest Science》2011,68(1):169-178

• Introduction   

Atmospheric deposition is an important input of major nutrients into forest ecosystems. The long-term goal of this work was to apply stable isotope methodology to assess atmospheric nutrient deposition in forest systems.  相似文献   

Effect of penetration speed on flesh firmness measured on stored kiwifruit     

Jinquan Feng  Andrew McGloneDavid Tanner  Anne WhiteShane Olsson  Mary Petleylan Woolf 《Postharvest Biology and Technology》2011,61(1):29-34

The effect of penetration speed on flesh firmness (FF) measurement by motorised penetrometer was examined for ‘Hayward’ (Actinidia deliciosa var. deliciosa) and ‘Hort16A’ (Actinidia chinensis Planch. var. chinensis) kiwifruit. Data was collected for penetration speeds varying from 4 to 40 mm s⁻¹ using stored fruit of FF ∼10 N; a typical minimum FF threshold for export from New Zealand. Measurements were made on a number of instruments (Instron, GUSS FTA, HortPlus, TA.XTplus), using fruit from different orchards and in each of two different seasons. As expected, FF values increased with increasing penetration speed. A firmness-speed model was developed, based on the Maxwell rheological model for viscoelastic materials, which proved adequate in describing the FF data in terms of the effect of penetration speed. The effect of penetration speed was not adversely influenced by cultivar, season or instrument type. Within the range of fruit firmness examined - stored fruit below 20 N - it was concluded that the firmness-speed model could be successfully used to compare firmness values generated using instruments operating at different penetration speeds.  相似文献   

A survey of the orangutan (Pongo pygmaeus wurmbii) population in and around Gunung Palung National Park, West Kalimantan, Indonesia based on nest counts   总被引：1，自引：0，他引：1  

Andrea E. Johnson  Bhayu Pamungkas  Andrew J. Marshall 《Biological conservation》2005,121(4):495-507

We conducted the first orangutan population census of Gunung Palung National Park, West Kalimantan, Indonesia, between April and September 2001. We used a refined line-transect nest-count methodology utilizing transect recounts to survey 69 km at 14 sites within the park and 14.2 km in the buffer zone. We present the first Bornean orangutan density estimate using complete site-specific parameters and long term monitoring of nest decay rates. Average orangutan density was 3.0 individuals/km², with densities ranging from 2.4 ind/km² in montane forest to 4.1 ind/km² in primary peat swamp. In addition, we tested alternative approaches to calculation of the nest-duration parameter. The second count of each transect resulted in 30% higher density estimates overall. We conclude that recounts should be incorporated into standard line-transect methodology. We estimate there to be ≈2500 individual orangutans in Gunung Palung, indicating the importance of this site in plans to conserve a network of viable orangutan populations. While logging may reduce densities, disturbed forest both inside and adjacent to the park has high conservation value as orangutan habitat. Further research into long-term orangutan population persistence in disturbed forest is needed.  相似文献