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1.
Jan-Olaf Meynecke Shing Yip Lee Norman C. Duke Jan Warnken 《Estuarine, Coastal and Shelf Science》2006,69(3-4):491
The speculation that climate change may impact on sustainable fish production suggests a need to understand how these effects influence fish catch on a broad scale. With a gross annual value of A$ 2.2 billion, the fishing industry is a significant primary industry in Australia. Many commercially important fish species use estuarine habitats such as mangroves, tidal flats and seagrass beds as nurseries or breeding grounds and have lifecycles correlated to rainfall and temperature patterns. Correlation of catches of mullet (e.g. Mugil cephalus) and barramundi (Lates calcarifer) with rainfall suggests that fisheries may be sensitive to effects of climate change. This work reviews key commercial fish and crustacean species and their link to estuaries and climate parameters. A conceptual model demonstrates ecological and biophysical links of estuarine habitats that influences capture fisheries production. The difficulty involved in explaining the effect of climate change on fisheries arising from the lack of ecological knowledge may be overcome by relating climate parameters with long-term fish catch data. Catch per unit effort (CPUE), rainfall, the Southern Oscillation Index (SOI) and catch time series for specific combinations of climate seasons and regions have been explored and surplus production models applied to Queensland's commercial fish catch data with the program CLIMPROD. Results indicate that up to 30% of Queensland's total fish catch and up to 80% of the barramundi catch variation for specific regions can be explained by rainfall often with a lagged response to rainfall events. Our approach allows an evaluation of the economic consequences of climate parameters on estuarine fisheries, thus highlighting the need to develop forecast models and manage estuaries for future climate change impact by adjusting the quota for climate change sensitive species. Different modelling approaches are discussed with respect to their forecast ability. 相似文献
2.
R. F. Coombs 《新西兰海洋与淡水研究杂志》2013,47(1):121-129
A model for an ‘open’ fish population is described. Basically an expansion of the classical catch equation, it includes a ‘population change’ coefficient to allow for changes in population size induced by causes other than fishing. The model relates this coefficient to catch, fishing effort, initial population size, and catchability coefficient. With observed catch and fishing effort data incorporated, the remaining parameters are estimated by minimising sums of squares. This estimation process is applied to data from both real and simulated fisheries, and is shown to be effective if the basic assumptions of the model are met. If this is not so considerable errors occur, and these are investigated with respect to the examples. 相似文献
3.
Jill N. Sheppard Nicola C. James Alan K. Whitfield Paul D. Cowley 《Estuarine, Coastal and Shelf Science》2011
Habitat variability is one of the factors influencing species richness within estuarine systems, and a loss of habitat can result in a restructuring of the estuarine ichthyofaunal assemblage, particularly if these conditions persist over long time periods. The potential effects of the loss of extensive submerged macrophyte beds (Ruppia cirrhosa and Potamogeton pectinatus) on an estuarine fish assemblage were investigated through an analysis of a long-term seine net catch dataset from the temporarily open/closed East Kleinemonde Estuary, South Africa. Catch data for a 12-year period, encompassing six years of macrophyte presence and six years of macrophyte senescence, indicated that the loss of this habitat did not influence species richness but changes in the relative abundance of certain species were evident. A shift in dominance from vegetation-associated species to those associated with sandy environments (e.g. members of the family Mugilidae) was observed. However, species wholly dependent on macrophytes such as the critically endangered estuarine pipefish Syngnathus watermeyeri were only recorded during years when macrophyte beds were present, while vegetation-associated species such as the sparid Rhabdosargus holubi persisted at lower levels of relative abundance. The reduced abundance of all vegetation-associated fish species during years of macrophyte senescence was probably reflective of declining food resources resulting from the loss of macrophyte beds and/or increased vulnerability to predation. Submerged beds of aquatic plants are therefore important habitats within temporarily open/closed estuaries, South Africa’s dominant estuary type. 相似文献
4.
《Marine Policy》2013
Proponents of catch share-based fisheries have claimed ecological stewardship can result from the assignment of individual catch quotas. This claim is examined by analyzing the distribution of benthic habitat protection measures adopted by quota-owning industry sectors within the exclusive economic zones (EEZs) of the U.S. (Alaska), New Zealand, and high seas seamounts within the Southern Indian Ocean Deepsea Fishers Association (SIODFA) competence area. Results suggest the protection of both benthic ecosystems and essential fish habitat (EFH) are marginal at best when quota owners have primacy in determining the boundaries of bottom trawl closures. The majority of the areas in these three regions that are closed to trawling are too deep to fish, may not contain vulnerable marine ecosystems, and do not have high abundances of commercially important species. “Freezing the footprint” of bottom trawling is not the best method for benthic habitat protection in areas where the fishing industry is actively fishing vulnerable habitats. Analytical methods should be applied to help determine boundaries of future bottom trawl closures rather than allowing the fishing industry to place benthic protection areas (BPAs) in areas where they are not interested in fishing. 相似文献
5.
Size at age, growth rates, seasonality of spawning, and size at maturity were described for the silver sweep Scorpis lineolatus off the coast of New South Wales, Australia. Estimates of age were made by counting annual zones in sections of otoliths. The ageing technique was validated using young‐of‐the‐year fish, staining fish with tetracy‐cline, and by marginal increment analysis. Silver sweep exhibited extreme longevity with an observed maximum age of 54 years and more than 50% of the fishery being greater than 15 years old. Growth was rapid during the first few years before reaching sexual maturity at 2–3 years and at a length of c. 17 cm fork length, after which growth slowed dramatically. Silver sweep displayed a winter spawning period. The fishery is unusual in that despite heavy fishing pressure and rapidly declining catches the age structure of the catch suggests a population that has been subjected to minimal fishing mortality. It is proposed that the large declines in commercial landings may be the result of serial depletion on local reefs and that current landings are being taken from schools of fish that have" receiveddate="little fishing pressure historically. 相似文献
6.
Fish behaviour relevant to fish catchability 总被引：1，自引：0，他引：1
Walsh Stephen J.; Godo Olav Rune; Michalsen Kathrine 《ICES Journal of Marine Science》2004,61(7):1238-1239
7.
Mary E. Livingston 《新西兰海洋与淡水研究杂志》2013,47(4):503-517
Abstract In September 1986, dense concentrations of freshly spawned hoki (Macruronus novaezelandiae) eggs were located in eastern Cook Strait. A follow‐up exploratory trawl survey of Cook Strait and the east coast of the South Island, in August and September 1987, located concentrations of spawning hoki in canyon features in Cook Strait, off the Kaikoura coast, and off Banks Peninsula. The largest concentration, 14 km long, 4 km wide, and up to 150 m thick occurred in Cook Strait Canyon, with catch rates of hoki up to 48 t h?1. Gonad conditions of male and female hoki showed they were actively spawning. Catch rates in Cook Strait Canyon were comparable to the main fishery on the west coast of the South Island but were much lower off Kaikoura and Banks Peninsula. Hoki associated with spawning concentrations were not feeding. Bycatch species were mostly ling (Genypterus blacodes) and spiny dogfish (Squalus acanthias), and both were preying on hoki. Spiny dogfish were also feeding on spawned fish eggs. The possible stock structure of hoki is discussed. 相似文献
8.
《Marine Policy》2014
This brief note is an update to the authors' "The Expansion, Limit and Decline of the Global Marine Fish Catch," published in the September 2012 issue of Marine Policy. That paper examined the steady increase in the world's catch from 1950 to 1989, its slight decline and rise to a final peak in 1996. This limit has been followed by a steady decline to 2010. Since there have been improvements in the technology of fishing and no reason to believe that there has been a reduction in fishing effort, then the apparent limit and subsequent decline in the catch suggests a reduction in the supply of fish and invertebrates in the world's oceans. The earlier paper also noted the geographic shift in the world's catch to Asia and the rise of China to become the world's largest catcher of fish. 相似文献
9.
《Marine Policy》2014
The applicability of catch shares programs is evaluated for the various fisheries of the Western Pacific Fishery Management Council region in each of the archipelagoes. Implementation of Catch Shares programs in the region is problematic, but would require better data to be done fairly and equitably. Catch shares are currently under initial consideration for the Hawaii and American Samoa longline fisheries and the Hawaii Deep 7 bottomfish fishery. It is argued that current conditions in all the other small boat fisheries in the region make them inappropriate for catch shares management. Overfishing and the “race for fish” are not yet an issue for these fisheries and some are underdeveloped. Catch share programs can cause significant negative social consequences for Western Pacific communities because data on fishermen's participation, catch histories, and motivations to fish for cultural needs is not adequate for any initial allocation scheme to be developed equitably. The prevailing Western Pacific cultural value of sharing the fish by gifting portions, sharing the catch widely and sharing fishing opportunities widely is in clear conflict with the individualized commercial profit motive philosophy of fisheries that are appropriate for catch shares. The small boat fisheries lack adequate monitoring and enforcement, and do not have a total allowable catch or quota. Nor do they usually have a demonstrated need for one. Preliminary community outreach by Council staff and community discussion of catch shares shows a general lack of information yet a potential for strong resistance to the imposition of catch shares. 相似文献
10.
小黄鱼Larimichthys polyactis体长-体重关系幂指数与产卵群体空间分布相关性研究 总被引：1，自引：0，他引：1
鱼类产卵群体的相关研究一直是渔业领域关注的热点,对鱼类的产卵期、产卵场的研究是鱼类生态习性研究方向的重要组成部分。本文在前期研究证实鱼类体长-体重关系幂指数可以指示鱼类产卵期的基础上,利用2004年4个季节的东海大面积调查数据,尝试利用同一时间点上的各个调查点幂指数信息来分析鱼类产卵场分布特征,结果发现,成熟产卵个体仅在春季出现,而未成熟产卵个体4季均有分布,以此推测小黄鱼存在"跳过产卵"现象。另外发现,单靠幂指数大小,不能区分各个产卵成熟阶段,也不能区分产卵个体与非产卵个体;而怀卵个体出现站点的幂指数平均值偏低于匀速生长,空间上也具有类似特征,即幂指数相对低的地方一般对应怀卵个体相对集中的水域。本文依据幂指数分布,推断小黄鱼成熟产卵群体有3块相对集中水域,即舟山渔场近海、济州岛西南侧和江外与舟外渔场临近水域。 相似文献
11.
《Estuarine, Coastal and Shelf Science》2006,66(1-2):67-83
The present study investigates the different uses and the functional roles of shallow habitats for fish fauna in the Venice Lagoon, by applying the functional guilds approach. Temporal (seasons) and spatial (location) changes within the lagoon show different habitat uses by fish assemblages, not influenced by local factors. Unvegetated mud habitats (salt marsh creeks and sub-tidal mud flats) and sparsely vegetated (seagrass) habitats show a common nursery role, especially for marine migrant fishes; but, contrary to other similar areas elsewhere shallow seagrass beds in the Venice Lagoon do not have a primary nursery role. This latter habitat has a more important role as a spawning ground for a resident, highly specialized component of the fish community. The habitat uses and their role to fish fauna illustrate the balance between predation risk and foraging profitability, as major factors structuring the fish assemblages. Spatial effects at a larger scale also highlight general characteristics of the fish assemblages in the Venice Lagoon. These indicate differences between the Northern sub-basin and the other two lagoon sub-basins, due to differences in the hydrodynamic regime, habitats distribution, and contributions from land and sea. 相似文献
12.
《African Journal of Marine Science》2013,35(1):891-902
In the existing management procedure for the South African anchovy Engraulis capensis resource, an initial Total Allowable Catch (TAC) is set at the start of the fishing season in January, before the year's recruitment of 0-year-old fish, an important component of the catch, is known. Recruitment is therefore assumed to be equal to the observed median. This TAC may be revised in May or June, after the actual recruitment has been estimated. This procedure incorporates a risk that, if recruitment is below the median, the stock could be adversely depleted before the mid-year recruitment survey. A simulation approach is used in this paper to assess the possible benefits, in terms of average annual catch and interannual fluctuations in catch, of three different methods of predicting recruitment earlier in the season, if such methods were available. The results show that the average annual catch could be increased theoretically by up to 48 per cent if a very precise prediction (CV = 0,1) could be made at the start of the fishing season. In practice, more modest improvements of 21 per cent by prerecruit surveys undertaken in March each year, or 16 per cent by means of a two-class ordinal prediction with 70 per cent success, may be attainable. However, these improvements would result in increased interannual fluctuations in catch, a situation which may be detrimental to the fishing industry. 相似文献
13.
《African Journal of Marine Science》2013,35(1):121-135
The trawl fishery, which targets Cape hake Merluccius spp. and Agulhas sole Austroglossus pectoralis, takes chokka squid Loligo vulgaris reynaudii as by-catch. Catch and effort data from the trawl fishery for the period 1978–1996 are used to obtain annual estimates of catch rate (catch per unit effort cpue) for that period. Examination of the cpue trend shows a sharp decline in the early 1980s and, in order to identify factors that could have influenced that decline, the distribution of fishing effort is investigated both temporally and spatially. There is a possible change in the incidence of squid-directed catches over time, but their overall scarcity could have had only a small impact on the annual cpue trend. Further, using distribution of fishing effort to evaluate the effects of possible changes in fishing patterns, rather than changes in resource abundance, on the trend in trawl cpue, it became clear that there had been a contraction of the trawling grounds and changes in fishing patterns in relation to depth over time. Finally, a general linear model (GLM) is developed to quantify the effect on cpue of factors such as vessel characteristic, depth and position of the drag, season and target species, so obtaining a standardized trawl cpue index of chokka abundance. Analysis of that trend reveals a mean 7.7% annual decline for the period investigated, which should be interpreted as a strong sign of resource decline. 相似文献
14.
Catch of marine fish grew from after WW II–1989, at which point it stabilized. In 1996 it began to decline. It continues to decline now, at a time when earth's population is expected to reach 10 billion by 2050. Since the factors driving the increase are primarily the growth in income, population, technology of catching fish and ever increasing fishing effort, it is to be expected that the aggregate marine catch will continue to decline. This decline has important implications for marine ecosystems but primarily its importance relates to the human use of other global resources such as food, water and world's climate. 相似文献
15.
Benjamin C. Green David J. Smith Sarah E. Earley Leanne J. Hepburn Graham J.C. Underwood 《Estuarine, Coastal and Shelf Science》2009,85(2):247-256
European intertidal salt marshes are important nursery sites for juvenile fish and crustaceans. Due to the increasing threat of habitat loss, the seasonal changes of salt marsh fish communities need to be understood in order to appreciate the ecological and economic importance of the saltmarsh habitat. This study was the first in Great Britain to investigate the seasonal changes of salt marsh fish communities and the variation in community structure between closely located marsh habitats. Between February 2007 and March 2008, five marshes on three estuaries of the Essex coastline were sampled using flume nets to block off intertidal creeks at high tide. Fourteen fish species were caught. The community overall was dominated by three species that made up 91.6% of the total catch: the common goby Pomatoschistus microps (46.2% of the total catch), juvenile herring Clupea harengus (24.3%), and juvenile and larval sea bass Dicentrarchus labrax (21.2%). Cluster analysis demonstrated clear seasonal patterns, with some community structures unique to specific marshes or estuaries. The marsh fish community shifts from a highly diverse community during spring, to a community dominated by D. labrax and P. microps in autumn, and low diversity during winter months. Gravimetric stomach content analysis of fish community identified three main trophic guilds; macroinvertivores, planktivores and omnivores. The macroinvertivore feeding guild contained D. labrax and P. microps, the two most frequently occurring species. This investigation demonstrates the importance of British salt marshes as nursery habitats for commercial fish species. 相似文献
16.
《Ocean & Coastal Management》2006,49(3-4):203-221
Coastal fisheries in Pacific island countries are characterised by a strong predominance of catches for subsistence purposes which involves mainly finfish and is difficult to quantify. In 1997–1998, a consumer survey conducted in the Northern Province of New Caledonia (Southwest Pacific Ocean) made it possible to indirectly estimate subsistence fishing production. Catch from subsistence fishing did not result in a significant change of the exploitation potential. The catch composition of subsistence fishing differed significantly from commercial fishing, with a higher proportion of species less vulnerable to exploitation. Interpretation of the consumer typology highlighted the importance of factors such as ethnic group and geographical location in explaining eating habits and therefore, indirectly, fishing behaviours. These results suggest that this fish consumption survey could assist in the design of subsistence fisheries monitoring programmes. 相似文献
17.
The catchability of western rock lobsters (Panulirus cygnus) during the spawning season (October and November) may be affected by their reproductive state. In this study, movement and food consumption of males and females of different reproductive states held in laboratory tanks were measured as proxies for catchability. Density of lobsters was found to influence both movement and food consumption. Solitary animals and, to a lesser extent, two lobsters per tank, were more sedentary and consumed significantly less food than animals at a density of three or four specimens per tank. Tests using three animals per tank confirmed that mature, unmated, and ovigerous females carrying early stage eggs moved more frequently away from their shelters than males or females carrying late stage eggs (P < 0.0001, d.f. = 3). Further, unmated females and females with early stage eggs recorded significantly higher food consumption (P < 0.0061, d.f. = 3) compared with males or females carrying late stage eggs. The greater time spent away from shelter and also food consumption make unmated females and females with early stage eggs likely to be more catchable than males or females with late stage eggs. As catchability is commonly used to obtain population estimates from survey data, these results have implications for surveys which use catch rates of breeding animals as indicators of egg production. 相似文献
18.
The feeding and spawning habitats of the overfished Atlantic bluefin tuna (BFT) are mapped in the Mediterranean Sea and used in the present proposal for selecting restricted fishing grounds. The feeding habitat is mainly traced by oceanic fronts of satellite-derived temperature and chlorophyll while the spawning habitat is mostly characterized by an important heating of surface waters. The proposal recommends opening the fishery in feeding areas in case the BFT stock is low (current situation). Only spawning areas at its latest stage could be opened once the stock has recovered to its optimum yield. Due to the possible concentration of fishing vessels if fishing areas are restricted (e.g. four-fold increase with a 1/16th restriction of the Mediterranean Sea) the inspection activities could be better targeted. Identified spawning grounds, opened or closed to fishing, could also be particularly monitored by control operations. Within the authorized areas, the habitat maps would guide fishermen to the favourable habitat reducing their costs. The habitat guided management could be able to adapt the spatial and temporal distribution of the effort to the requirements of both the fisheries’ control and the resource. Its implementation is likely to protect the stock (a) by apparently decreasing illegal fishing which accounts in the recent years for more than 1/3rd of total catches, (b) by protecting the spawners to ensure a suitable recruitment and (c) by distributing the effort to respect the population structure. The first species studied is the emblematic bluefin tuna which is at high risk of collapse due to overfishing. The approach is a priori transposable to other epipelagic species of commercial importance. 相似文献
19.
Information coming from fishery monitoring, surveys and experimental fishing with participation of fishers was employed to determine the impact of an artisanal gear, ‘boliche’, on the biodiversity of the Ciénaga Grande de Santa Marta (CGSM), an estuarine lagoon on the Caribbean coast of Colombia. Fishery monitoring (catch data) included landings before (1968 and 1978) and after (1994–1996) the introduction of the boliche in the CGSM (1985), whereas surveys were conducted seasonally during 1993–1994. Fishing experiments involved evaluating different mesh sizes and the short-term effect of physical disturbance by the boliche. Monitoring suggested potential trophic effects of this fishing gear: the catch of large, long-lived, carnivorous species declined after the introduction of the boliche in the CGSM, whereas catch rates of smaller, shorter-lived, and lower trophic level species increased. Surveys revealed that the boliche retained 41 species. The by-catch made up 62% of the total catch and the remaining 38% involved the three target species Eugerres plumieri, Mugil incilis and Cathorops spixii. Selectivity experiments showed that 2.5 in. stretched mesh size gill nets caught more species than the 3.0-in. mesh. The smaller mesh also increased the risk of a critical reduction in the spawning stock of target species (notably E. plumieri); a situation that could affect the fish community if mesh sizes lower than 2.5 in. were intensively used. Suspended particulate matter significantly increased after fishing activity, with higher resuspension on mud-shells and mud substrata, whereas dissolved oxygen showed no appreciable changes after fishing operations. Notwithstanding, the activity of the boliche would generate sediment resuspension between 382 and 470 t day−1, which could lead to potential cascade impacts on water quality. We propose a framework of redundancy in management measures in order to simultaneously reach management and conservation goals. 相似文献