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1.
Southern rock lobster (Jasus edwardsii) support significant commercial and recreational fisheries in Tasmania, Australia. Since the mid 1990s the number of persons holding recreational lobster licences increased by over 80%, with c. 15 500 persons licensed in 2002/03. Assessment of the recreational fishery has been undertaken periodically since 1996 using a telephone‐diary survey method. The fishery was concentrated off the south‐east and east coasts of Tasmania and characterised by strong seasonality in catch and effort, which peaked markedly early in the fishing year (November‐January). Although pots were the most popular fishing method, daily catch rates by divers were more than double those for pots. Divers selectively harvested larger lobsters than those taken by pots and more frequently attained the daily bag limit of 5 lobsters. The estimated recreational harvest increased significantly since 1996/97 and in 2002/03 effectively reached a management trigger level of 10% of the total allowable commercial catch, flagging a review of recreational management arrangements.  相似文献   

2.
The southern rock lobster, Jasus edwardsii, is South Australia's most valuable fisheries resource, with an annual landed value of c. AU$100 million. Approximately 80% of this revenue comes from the southern zone (SZ) rock lobster fishery, which has been managed under an individual transferable quota system since 1993. The total allowable commercial catch is currently set at 1900 tonnes. Long‐term spatial trends in catch and effort were analysed over the period 1970–2005 to investigate possible changes in the spatial dynamics of the fleets as a result of quota introduction. Data indicate that the fishery contracted into three main Marine Fishing Areas (MFAs) after 1993. In particular, the long‐term catch average in MFA 51 decreased from 185.4 tonnes pre‐quota to 59.8 tonnes post quota. This MFA is located in the northern region of the SZ and is one of the furthest MFAs from the main fishing ports in the region. The fishery is also spatially contracted within MFAs. Approximately 80% of the annual catch comes from <60m depth despite catch rates being 2–3 times greater in offshore sites as evidenced from both fishery‐dependent and independent sources. Such trends appear driven by recent market preferences that select for small (<1 kg), red‐coloured lobster that are primarily located on inshore grounds. As a result, fishers now target inshore sites to maximise returns under the quota‐based system. The observed shift in the spatial dynamics of the SZ has clear implications for the biological performance indicators on which the fishery is managed. Specifically, the results highlight the need for a fishery‐independent assessment of the resource that provides estimates of catch rate and biomass independent of current harvest strategies. Preliminary results from a trial survey undertaken in 2005/06 and 2006/07 show higher lobster abundance in lowly exploited offshore sites compared with inshore areas. These trends highlight the need for refined spatial management of the resource, which is the focus of the new management plan for the fishery.  相似文献   

3.
The western rock lobster fishery is one of the most valuable single‐species fisheries in Australia, valued at AU$300 million per year. The impact of environmental factors such as lunar cycle and swell on the daily catch rate of the western rock lobster (Panulirus cynus) is of particular interest in the stock assessment and management of the fishery. The variation in daily catch rates was examined for two periods (migrating period November‐January, non‐migrating period February‐June), at different depths in three management zones for three categories of lobster (undersize, legal size, and setose). Regression and transfer function models for relationships between catch rates and environmental data were considered and compared. The lunar cycle has a significant impact on the daily catch rates with c. 30% lower catch rate during the full moon and c. 20% higher catches near the new moon. This impact occurs mainly during the non‐migrating period both in deep water (40–100 m) and shallow water (<40 m). The swell on the day before fishing was also shown to be significantly related to the catch rate with an increase of c. 10–15% for an increase in swell from light to moderate or moderate to high. These environmental factors can be used to standardise catch rates to provide an improved abundance index for stock assessment. Also, management closures are being considered for 3–5 days over the low catch rate, full moon period to reduce fishing costs and lower fishing effort.  相似文献   

4.
Comprehensive, aggregate nutrient budgets were established for two compartments of the North Sea, the shallow coastal and deeper open regions, and for three different periods, representing pre-eutrophication (∼1950), eutrophication (∼1990) and contemporary (∼2000) phases. The aim was to quantify the major budget components, to identify their sources of variability, to specify the anthropogenic components, and to draw implications for past and future policy. For all three periods, open North Sea budgets were dominated (75%) by fluxes from and to the North-East Atlantic; sediment exchange was of secondary importance (18%). For the coastal North Sea, fluxes during the eutrophication period were dominated by sediment exchange (49% of all inputs), followed by exchange with the open sea (21%), and anthropogenic inputs (19%). Between 1950 and 1990, N-loading of coastal waters increased by a factor of 1.62 and P-loading by 1.45. These loads declined after 1990. Interannual variability in Atlantic inflow was found to correspond to a variability of 11% in nutrient load to the open North Sea. Area-specific external loads of both the open and coastal North Sea were below Vollenweider-type critical loads when expressed relative to depth and flushing. External area-specific load of the coastal North Sea has declined since 1990 from 1.8 to about 1.4 g P m−2 y−1 in 2000, which is close to the estimate of 1.3 for 1950. N-load declined less, leading to an increase in N/P ratio.  相似文献   

5.
As part of a study of the reasons for declining commercial banana prawn catches in the Weipa area of the Gulf of Carpentaria, and in order to assess whether changes in predator numbers may be a factor influencing prawn numbers, the species composition, numbers and biomasses of fishes in the Embley estuary were re-examined in February 2005 for comparison with the results of a study between 1986 and 1990. The new study duplicated previous methods and used the same sampling sites and the same gear employed during February sampling periods from 1986 to 1990. Overall, the species diversity and catch rates, as well as the numbers of penaeid prawn predators had changed little over 20 years. The overall catch rate for 2005 was 37.4 g m−1 h−1, not significantly different from the overall catch rate of 32.8 g m−1 h−1 (SE 6.6) for the period from 1987 to 1989. The results are discussed in relation to environmental factors and climate change, as well as the substantial declines in prawn catches, which had fallen from over 800 tonnes per annum prior to 1998, to about 70 tonnes per annum.  相似文献   

6.
Based on the assumption that depleted stocks would have recovered during a six-year layoff from fishing, trapping for deep-water spiny lobster Palinurus delagoae and slipper lobster Scyllarides elisabethae off eastern South Africa resumed in 2004 until 2007. A generalised linear modelling approach was used to investigate the effects of year, sampling area, depth, month and trap soak-time on catch and lobster size, and to construct standardised abundance indices. The renewed trapping rapidly reversed partially restored nominal catch rates. Fishing strategy changed from targeting spiny lobsters during the first months of each fishing season to targeting slipper lobsters during later months. Small spiny lobsters were abundant in the southern area, identified as a recruitment hotspot. Spiny lobster abundance and size in this area increased over four years of fishing, but conversely, large adult spiny lobsters predominated in the central and northern areas, where trapping depleted their abundance over time. The adult populations in the central and northern areas are upstream from the recruitment hotspot, and are presumably a source of larvae. Slipper lobster abundance peaked in 2005, remained relatively constant across areas, and increased with depth. Trapping for deep-water lobster is unlikely to be sustainable in its present form. However, the clear gradients in spiny lobster size and abundance by sampling area and depth provide a good framework for spatial management planning.  相似文献   

7.
The spiny lobster Jasus edwardsii (Hutton) supports a thriving new fishery at the Chatham Islands, about 770 km east of New Zealand. Commercial fishing for J. edwardsii started in November 1965, and within 2 years the area became a major centre of New Zealand's large spiny lobster fishery, which earned >NZ$5,000,000 in 1967. Over 12 months (September 1966 to August 1967) landings at the Chatham Islands made up 39.8% of the total New Zealand spiny lobster catch of 16,600,0001b.

In the first year of fishing 2,177,923 lb of spiny lobsters were caught, and in the second 7,129,658lb—a 227% increase. Fishing effort also increased substantially: average number of boats fishing each month rose by 174% in the second year, and the total number of boat‐fishing days by 152%. Most specimens of J. edwardsii caught are large and mature, typical of a virgin stock.  相似文献   

8.
Precious corals have been commercially exploited because of their legendary and cultural importance for many centuries in the Mediterranean and for almost one century in the Northwest Pacific. Although the precious coral fishery in Taiwan dates back to the 1920s, relevant studies on biology and ecology of resources are relatively scarce. The management of the precious coral fishery in Taiwan was officially instituted in January 2009, when data on the catch and effort of the fishery were recorded. In this study, the catch-effort data of the fishery were examined to explore the temporal and spatial patterns in composition and abundance of Corallium and Paracorallium spp. around Taiwan. A total landing of 3233.0 and 2906.8 kg precious corals were recorded for 2009 and 2010, respectively. Less than 5% of those amounts were from live colonies. A high proportion of fossilized colonies in the catch reflect the non-selective nature of the fishing gear; however, the factors that cause colonies to collapse are not exclusive to the impact of the fishery. Momo coral was dominant in the production for both years, followed by Miss coral. The total production of precious corals correlated positively with fishing efforts, while a weak relationship was found between the production of live colonies and fishing efforts. The fishing efforts mainly aggregated in designated fishing ground A (DFG-A) for both years, while the production of live colonies mainly occurred in DFG-E. The monthly occurrence rate of live colonies decreased over the past 2 years. Although fluctuating significantly, the CPUE of dominant species exhibited an apparent decreasing pattern. High aggregation of the fishing efforts in specific regions and low numbers of live colonies in the production should be carefully taken into account when amending management regulations in the future. The establishment of marine protected areas, in addition to the strict controls that already apply, should be considered to not only sustain the population structure of the sessile animals but also their function in the marine ecosystem.  相似文献   

9.
The scale of landscape pattern formation of an ecological community may provide clues as to the processes influencing its spatial and temporal dynamics. We conducted an examination of the spatial organization of an annual seagrass (Halophila decipiens) in an open ocean setting at two spatial scales and growing seasons to identify the relative influence of external (hurricanes) versus internal (clonal growth) factors. Visual surveys of seagrass cover were conducted over 2 years within three replicate 1 km2 study areas each separated by ∼25 km in an inshore–offshore transect along the southwest coast of Florida at depths between ∼10 and 30 m. A towed video sled allowed observations of seagrass cover of 1 m2 areas approximately every 6 m over thousands of meters of evenly spaced transects within the study areas (coarse scale). The towed video revealed that 17.5% of the seafloor was disturbed irrespective of location or sample time. Randomly selected 10 × 10 m quadrats within the larger, 1 km2 study areas were completely surveyed for seagrass cover by divers at 0.625 m2 resolution (fine scale). The coarse-scale observations were tested using both conventional geostatistics and an application of a time-series technique (Runs test) for scale of seagrass cover contiguity. Fine-scale observations were examined using conventional geostatistics and a least squares approach (cumulative logistic).  相似文献   

10.
Because the marine picoplanktonic communities are made up of phylogenetically different microbial groups, the re-evaluation of key processes such as bacterial secondary production (BSP) has become an important contemporary issue. The difficulty of differentiating the metabolic processes of Bacteria from the rest of the microorganisms in the water column (i.e., Archaea and Eukarya) has made it difficult to estimate in situ BSP. This work presents the seasonal variability of the prokaryote secondary production (PSP) measured by the incorporation of 14C-leucine in the oxygen minimum zone (OMZ) off central-southern Chile. The BSP and potential archaeal secondary production (PASP) were determined through the combined use of 14C-leucine and N1-guanyl-1, 7-diaminoheptane (GC7), an efficient inhibitor of archaeal and eukaryote cell growth. BSP accounted for the majority of the PSP (total average, 59 ± 7.5%); maximum values were ∼600 μg C m−3 h−1 and, on several dates, BSP represented 100% of the PSP. Similarly, PASP was also an important fraction of the PSP (total average, 42.4 ± 8.5%), although with levels that ranged from not detectable (on given dates) to levels that represented up to ∼97% of PSP (winter 2003). Our results showed that both Bacteria and Archaea accounted for almost equal portions of the prokaryote heterotrophic metabolism in the OMZ, and that PASP is notoriously enhanced through temporal pulses of heterotrophy. This indicates that, at least in marine systems with high abundance of Archaea (e.g., mesopelagic realm), the secondary production obtained through methods measuring the uptake of radiolabeled substrates should be considered as PSP and not as BSP. If the latter is the target measurement, then the use of an inhibitor of both archaeal and eukaryote cell growth such as GC7 is recommended.  相似文献   

11.
The larval fish assemblage was investigated in the shallow, nearshore region of a proposed marine protected area in eastern Algoa Bay, temperate South Africa, prior to proclamation. Sampling was conducted at six sites along two different depth contours at ∼5 m and ∼15 m to assess shore association. Larvae were collected by means of stepped oblique bongo net tows deployed off a ski-boat, twice per season for 2 years between 2005 and 2007. In total, 6045 larval fishes were collected representing 32 families and 78 species. The Gobiidae, Cynoglossidae, Clupeidae, Engraulidae and Sparidae were the dominant fish families. Catches varied significantly among seasons peaking in spring with a mean of ∼200 larvae/100 m3. Mean overall larval density was higher along the deeper contour, at ∼15 m (40 larvae/100 m3). The preflexion stage of development dominated catches at the ∼5 m (80%) and ∼15 m (73%) depth contours. Body lengths of Argyrosomus thorpei, Caffrogobius gilchristi, Diplodus capensis, Heteromycteris capensis and Solea turbynei, all estuary associated species, were larger at the shallow sites nearer to shore. Larvae of coastal species that produce benthic eggs dominated catches (75%) in the shallow sites (∼5 m) but were less abundant (32%) farther from shore at the deeper (∼15 m) sites. All developmental stages of D. capensis, Engraulis capensis, H. capensis, Sardinops sagax and two Pomadasys species were found in the study area. It appears that some species use the shallow nearshore as a nursery area.  相似文献   

12.
A multi-proxy approach based on organic (organic carbon, alkenones, and C/N) and inorganic geochemical proxies (biogenic opal, inorganic carbon, Fe, Ti, and Ca) preserved in the sediments of the Jacaf channel (CF7-PC33; 44°21′S, 72°58′W, 510 m water depth), Chilean fjords, yields evidence of major past productivity fluctuations in accordance with climatic changes over the last ∼1800 years. The downcore record clearly shows two productivity/climate modes. The first period, prior to 900 cal yr BP, is characterized by decreased marine productivity and a reduced continental signal, pointing to diminished precipitation and runoff. In contrast, the second period between ∼750 cal yr BP and the late 1800s (top of core) is illustrated by elevated productivity and an increased continental signal, suggesting higher precipitation and runoff. Both time intervals are separated by a relatively abrupt transition of ∼150 years which roughly coincides with the beginning of the Little Ice Age. The increased content of freshwater diatoms and Chrysophyte cysts that characterize the last 200 years of the latter mode coincides with a significant decrease in the carbonate content of the sediment; together they further indicate increased terrigenous contributions and decreased marine carbonate productivity at the end of the Little Ice Age. The correspondence between our record and other paleoclimate studies carried out in South America and Antarctica demonstrates that the Chilean fjord area of Northern Patagonia is not just sensitive to local climatic variability but also to regional and possibly global variability.  相似文献   

13.
A survey within the French National Programme of Ecotoxicology was carried out in 2002, 2003 and 2004 to study the response of Nereis diversicolor populations (Polychaeta, Nereididae) to the impact of pollution in the Authie estuary (non-contaminated site) and in the Seine estuary (contaminated site). In the period studied, the density varied from 672 ind. m−2 to 3584 ind. m−2 in the Authie estuary and from 80 ind. m−2 to 920 ind. m−2 in the Seine estuary. Biomass varied from 3.94 g m−2 (dry weight) in February 2004 to 38.0 g m−2 in August 2003 in the Authie estuary and from 3.4 g m−2 in February 2002 to 0.6 g m−2 in February 2004 in the Seine estuary. Density and biomass of the populations of N. diversicolor were consistently lower in the Seine estuary than in the Authie estuary. Size frequency histograms permit the analysis of the cohorts as well as the elaboration of the growth curves. For the individuals from the Authie estuary, the relation between dry weight (DW) and length L3 (prostomium, peristomium and chaetiger 1) was DW = 4.2205 L32.9832. For those from the Seine estuary, the relation between dry weight and L3 was DW = 0.4697e1.7209L3. The individuals of N. diversicolor should belong to eight cohorts in Authie estuary (two cohorts each year) instead of six cohorts for those from the Seine estuary. These differences can be attributed to the effect of pollution on the population of N. diversicolor.  相似文献   

14.
The hake resource is the most important commercial fish species in the demersal sector of Namibia's fisheries, both in terms of annual catch and contribution to Gross Domestic Product (GDP). The fishery now spans four decades. In the 1960s and 1970s, hake were exploited heavily by mainly foreign fleets, total catches peaking at more than 800 000 tons in 1972. The first control measures, the use of a minimum mesh size of 110 mm and the allocation of quotas to each member country participating in the hake fishery, were implemented by the International Commission for the Southeast Atlantic Fisheries in 1975. In 1990, the Namibian Government took action to control fishing activities in Namibian waters, and the enactment of its Fisheries Policy (1991) and Sea Fisheries Act of 1992 provided for the control measures to be taken. The conservative management strategy adopted between 1990 and 1993 resulted in gradual increase in hake biomass, but thereafter the stock declined. The hake fishery is currently managed on the basis of a total allowable catch that takes into consideration the rate of increase or decrease in the size of the resource. Since 1990, the demersal trawl fishery has accounted for approximately 90% of the total hake catch. The resource is subjected to both directed fishing and bycatch, the latter taken in directed fisheries for species such as horse mackerel, monkfish and sole.  相似文献   

15.
The mixed layer of the ocean and the processes therein affect the ocean’s biological production, the exchanges with the atmosphere, and the water modification processes important in a climate change perspective. To provide a better understanding of the variability in this system, this paper presents time series of the mixed layer properties depth, temperature, salinity, and oxygen from Ocean Weather Station M (OWSM; 66° N,2° E) as well as spatial climatologies for the Norwegian Sea. The importance of underlying mechanisms such as atmospheric fluxes, advective signals, and dynamic control of isopycnal surfaces are addressed. In the region around OWSM in the Norwegian Atlantic Current (NwAC) the mixed layer depth varies between ∼20 m in summer and ∼300 m in winter. The depth of the wintertime mixing here is ultimately restrained by the interface between the Atlantic Water (AW) and the underlying water mass, and in general, the whole column of AW is found to be mixed during winter. In the Lofoten Basin the mean wintertime mixed layer reaches a depth of ∼600 m, while the AW fills the basin to a mean depth of ∼800 m. The temperature of the mixed layer at OWSM in general varies between 12 °C in summer and 6 °C in winter. Atmospheric heating controls the summer temperatures while the winter temperatures are governed by the advection of heat in the NwAC. Episodic lateral Ekman transports of coastal water facilitated by the shallow summer mixed layer is found important for the seasonal salinity cycle and freshening of the northward flowing AW. Atmospheric freshwater fluxes have no significant influence on the salinity of the AW in the area. Oxygen shows a clear annual cycle with highest values in May-June and lowest in August-September. Interannual variability of mixed layer oxygen does not appear to be linked to variations in any of the physical properties of the mixed layer.  相似文献   

16.
The influence of prolonged mouth closure on the population dynamics of the caridian shrimp, Palaemon peringueyi and the estuarine isopod, Exosphaeroma hylocoetes, in the littoral zone of temporarily open/closed Kasouga Estuary located on the south-eastern coastline of southern Africa was assessed monthly over the period October 2007 to September 2008. Prolonged mouth closure of the estuary contributed to hypersaline conditions (psu > 35) prevailing throughout the estuary for the last four months of the study. The high salinities coincided with a decrease in the areal extent (up to 80%) of the submerged macrophytes, mainly Ruppia maritima, within the littoral zone of the estuary. Total abundance and biomass values of the shrimp and isopod over the period of investigation ranged from 0 to 14.6 ind m−2, from 0 to 13.3 mg dwt m−2, from 12 to 1540 ind m−2 and from 0.1 to 2.16 mg dwt m−2, respectively. Maximum values of both the shrimp and isopod were recorded in the upper reaches of the estuary in close association with R. maritima. Over the course of the investigation, both the abundance and biomass values of the shrimp decreased significantly (P < 0.05 in both cases) which could be related to reduced habitat availability, R. maritima, that acts as a refuge against fish predation. Additionally, the decrease in abundance and biomass values could be attributed to reduced recruitment opportunities for the shrimp and the cessation of reproduction in the estuarine isopod. The establishment of a link to the marine environment following an overtopping event in September 2008 contributed to a decrease in salinity within the system although no recruitment of either the isopod or shrimp was recorded.  相似文献   

17.
Today, the tuna fishery of the western and central Pacific is one of the world's largest fisheries. Annual catches exceed 2 million mt—approximately 50% of the global tuna catch—with an estimated landed value of USD 3 billion (in 2005). The fishery expanded rapidly from the mid 1980s, following the development of the purse-seine fishery. From the mid 1990s, it was recognised that a Regional Fisheries Management Organisation was required to facilitate cooperation in the management of the resource. Following almost a decade of negotiations and planning, the Western and Central Pacific Fishery Commission (WCPFC) was established in 2004. During the interim period, stock assessments for the key tuna species were developed and revealed that for two species (yellowfin and bigeye tuna) there was concern regarding the increased levels of fishing mortality. However, declarations and resolutions calling for restraint in the expansion of fishing effort were largely unheeded over the last decade and, to date, the WCPFC has been unable to introduce any measures to effectively reduce (or limit) the level of fishing mortality on yellowfin and bigeye tuna. This paper proposes a number of mechanisms for improving the performance of the WCPFC with respect to meeting the conservation and management objectives of the commission and argues that Pacific Island nations need to collectively take the lead to ensure the effective management of the resource.  相似文献   

18.
The range expansion patterns of Spartina alterniflora and the roles which sexual reproduction and asexual propagation play in range expansion were investigated at the Chongming Dongtan nature reserve in the Yangtze Estuary, China. Two range expansion patterns of S. alterniflora at its advancing fronts could be found (1) S. alterniflora–mudflat front (S–M) and (2) S. alterniflora–Scirpus mariqueter–mudflat front (S–S–M). One feature revealed by this study was that a flush of seedling recruitment and establishment in spring was a crucial way for S. alterniflora to colonize new habitats and achieve a fast rate of range expansion. The mean number of seedlings recruited at the S–M front was much higher than that at the S–S–M front. Once established, the survivorship of seedlings was high, both at the S–M and S–S–M fronts. The established seedlings formed new tussocks quickly by vegetative tillering and growth of rhizomes and these finally merged into dense meadows. The mean distance of range expansion of S. alterniflora, after one growing season at the S–M front, was 25.4 ± 3.1 m yr−1 and 2.7 ± 0.5 m yr−1 at the S–S–M front. Sexual reproduction by seedlings and asexual propagation by tillering and growth of rhizomes were the two main means by which S. alterniflora could maintain a fast rate of range expansion on the salt marshes of the Yangtze Estuary. The colonization behaviors of S. alterniflora on advancing fronts differed as a reaction to various external and internal factors. The impact of abiotic and biotic factors governing the range expansion of S. alterniflora and its implications for the spatial structure of tidal wetlands are discussed.  相似文献   

19.
Five oceanographic surveys were carried out in the East China Sea (ECS) and Yellow Sea from 1999 to 2003. In all, seven different sections were surveyed, but one section (the PN section) was observed on every cruise. Two time-series stations were also surveyed, one located at the Changjiang River mouth, the other over the continental shelf in the PN section.We identified biogeochemical characteristics for waters close to the Changjiang Estuary and in the Kuroshio waters (KW), respectively. Resuspension is a strong feature near bottom over the ECS continental shelf, with suspended matter values 13 times higher than that for the surface. A model of particulate organic carbon (POC) dynamics based on a rectangle equation reveals that POC concentration close to the Changjiang Estuary varies with a semidiurnal period of ∼13 h, coinciding with the tidal period. The upper limit for POC residence times in the seasons we covered over the shelf are estimated to be on the order of weeks and generally increase seaward from near the Changjiang Estuary to the KW. Short POC residence times suggest that POC in the ECS is rapidly exported from euphotic waters.A nepheloid layer, observed as elevated suspended matter in near the bottom of the water column, is important in particle transfer over the shelf, especially in winter when the residual current flows mainly eastward. Cross-shelf transport of POC via the nepheloid layer is estimated to be 0.22 × 1012 g yr−1. Comparison with other work indicates that POC transport is ∼2% of the Changjiang POC input.  相似文献   

20.
Limited entry and biological quotas were implemented in the lobster fishery of the Northwestern Hawaiian Islands in 1991, during a period of declining stock abundance. A companion use-it-or-lose-it permit provision has had the perverse effect of increasing fishing effort during times of declining stocks. Despite its unfavorable short-term prospects, the fishery has the potential to be very lucrative for a small number of boats over the long term. This paper introduces a dramatically different management regime that would create ownership rights in a private management corporation for the current limited-entry permit holders. This corporation would function within a renewable operating contract with the government to protect the public interest in the conservation of the lobster population and its associated ecosystem. Published by Elsevier Science Ltd.  相似文献   

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