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- 1. Conservation and rehabilitation efforts for lake sturgeon Acipenser fulvescens throughout the Great Lakes include the re‐establishment of self‐sustaining stocks in systems where they have been extirpated.
- 2. Information on the suitability of potential lake sturgeon habitat in tributaries is important for determining their capacity to support lake sturgeon stocking and to develop system‐specific rehabilitation strategies.
- 3. Geo‐referenced habitat information characterizing substrate composition, water depth, and stream gradient were applied to a life‐stage specific lake sturgeon habitat suitability index in a geographic information system to produce spatially explicit models of life‐stage specific habitat characteristics in five northern Lake Michigan tributaries from which lake sturgeon have been extirpated.
- 4. Habitat models indicated that high quality lake sturgeon spawning and staging habitat comprised 0 to 23% and 0 to 9% of the available habitat, respectively, whereas high quality juvenile lake sturgeon habitat was relatively ubiquitous throughout each river and comprised 39 to 99%.
- 5. Comparison of these data to lake sturgeon habitat availability in Lake Michigan tributaries currently supporting populations indicated that spawning and staging habitats may limit the ability of these systems to support spawning. Efforts to re‐establish lake sturgeon populations in these systems should consider the creation of spawning and staging habitat to increase reproductive and recruitment potential prior to the initiation of stocking efforts.
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- 1. Historically, ecological assessment of lakes has depended on open‐water chemical and phytoplankton analysis, with trophic status determined by chlorophyll a and total phosphorus following the general protocol of the OECD lake classification scheme. This has been accompanied by a prevailing opinion that the littoral zone of lakes is too heterogeneous to allow meaningful inter‐lake comparisons.
- 2. Council of the European Communities Directive 2000/60/EC establishing a framework in the field of water policy (the Water Framework Directive) requires a broader approach to ecological assessment, including the need to incorporate a range of biotic variables. This paper describes the results of a monitoring programme designed to determine within‐ and among‐lake variation of macroinvertebrate communities found in defined mesohabitats of 22 lakes incorporating a range of lake types. Three sampling approaches were applied to the study.
- 3. Triplicate macroinvertebrate samples from a cobble/pebble mesohabitat of 11 lakes showed that community composition from a standard habitat was robust.
- 4. Twinned samples from contrasting habitats of pebble/cobble and macrophyte dominated mesohabitats of 21 lakes had greater similarity within than among lakes. This showed that even across contrasting habitat structure, macroinvertebrate assemblages can provide a reliable lake‐specific indicator.
- 5. Multivariate analysis of replicate samples from 15 visually distinct mesohabitats in one lake showed that within‐lake variation could, nevertheless, be identified as distinct clusters of invertebrate assemblages.
- 6. Conclusions from the work are that variations within lakes were nested in among‐lake variation across a range of lake types, and that macroinvertebrate assemblages can provide meaningful assessment of ecological differences across lakes. Monitoring can, however, produce a substantial amount of ‘noise’ from the data that reflects the complexity of macroinvertebrate community structure in littoral zones. It is recommended that incorporation of macroinvertebrates in ecological assessment is most useful when confined to well defined mesohabitats rather than attempt to incorporate a complete range of mesohabitats within a single lake.
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- Pelagic spawning riverine fish (pelagophils) spawn in free‐flowing river habitats with downstream drift of eggs and larvae but the spatial scale is often unknown, and this constitutes a major ecological knowledge gap.
- In the arid Darling River in south‐eastern Australia, the present objectives were: (i) to determine the potential downstream dispersal distance of young golden perch (Macquaria ambigua); and (ii) to evaluate whether provision of environmental water enhanced dispersal of young fish from Menindee Lakes to the lower Darling River (LDR) while also cueing further spawning in downstream lotic reaches.
- Golden perch spawned in unregulated lotic tributaries on a flood pulse and larvae drifted or dispersed >1,600 km downstream and entered large ephemeral productive floodplain lake nursery habitats as fully scaled fingerlings.
- Planned releases of environmental water cued golden perch spawning in the LDR and enabled juvenile fish to disperse downstream from the Menindee Lakes nursery into receiving populations in the LDR, Great Darling Anabranch, and southern Murray River, with some fish potentially completing an active migration of >2,100 km by age 1 year.
- The Darling River case study highlights the need for a system‐scale approach to the conservation management of pelagophilic fish, along with multi‐year perennial flow strategies to improve ecosystem integrity in large rivers globally.
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- 1. In 2006, two periods of hypoxia resulted in the death of approximately 35 tonnes of black bream (Acanthopagrus butcheri) in Lake Indoon, a small inland lake in Western Australia.
- 2. Acanthopagrus butcheri was the first fish species to be recorded in this lake, along with the mosquitofish (Gambusia holbrooki) which was also observed during sampling in 2006. Acanthopagrus butcheri appears to have been introduced to Lake Indoon between 1998 and 2003 and formed a self‐sustaining population. It is believed to have been deliberately introduced for the purpose of creating a recreational fishery, despite the existence of substantial penalties for illegal translocation of fish in Western Australia.
- 3. Recent human‐induced environmental changes, including rising groundwater and salinization, have probably aided the establishment of both species in Lake Indoon. The importance of salinity to recruitment success by A. butcheri was indicated by the presence of only two age classes in 2006, with estimated recruitment dates coinciding with the years of highest recorded salinity in the lake.
- 4. The ‘fish kills’ provided an opportunity to examine aspects of A. butcheri biology in a relatively low salinity environment which is atypical for this estuarine species. In particular, the recruitment period in Lake Indoon was delayed until autumn/winter, rather than spring/summer as seen in other populations. Biological responses in Lake Indoon have implications for natural populations living in estuaries with modified salinity regimes.
- 5. The ecological, social and economic impacts potentially arising from the introduction of fish to Lake Indoon, which is an important migratory bird habitat and a recreational amenity for local residents and tourists, illustrate the complexities of fish translocation and the need for rigorous assessment before stocking to identify potential costs and benefits.
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Xiaoyong Xie Zhou Wu Chun‐Chieh Wang Yijian Fu Xueping Wang Peng Xu Xing Huang Yongyan Liao Shiang‐Lin Huang Kit Yue Kwan 《水产资源保护:海洋与淡水生态系统》2020,30(2):260-272
- Identification, protection and enhancement of essential habitats are priority issues for management and restoration of exploited species. The shores utilized by Asian horseshoe crabs as nurseries were surveyed and the coastal habitat characteristics were described in the northern Beibu Gulf of China. Regression models were applied to explore species‐habitat relationships.
- Fourteen and ten nursery sites were identified for Tachypleus tridentatus and Carcinoscorpius rotundicauda populations, respectively. Xiacun and Jinhaiwan in the eastern region of the northern Beibu Gulf were the essential nurseries for T. tridentatus, whereas Shanxin and Jiaodong in the western part were the primary nursery shores for C. rotundicauda. These shores supported high densities (4–6 individuals/100 m2) of juvenile horseshoe crab populations.
- Mangrove and seagrass coverage area, coupled with sediment physico‐chemical parameters, particularly grain size, and the environmental heterogeneity of nursery habitats explained the distribution pattern of juvenile populations. Most juvenile populations were found along the outer fringe of mangroves in the small shallow estuary, particularly near outflows of tidal creeks with generally higher chlorophyll a and organic carbon contents. The distribution of high‐density juvenile populations of both species also overlapped with areas of seagrass patches.
- These findings highlight the importance of mangroves and seagrasses in the nursery habitat use of Asian horseshoe crabs. Preserving the estuarine habitats with these vegetation types and identifying the high‐use nursery sites should be prioritised in China and other Asian places to conserve the declining Asian horseshoe crab populations.
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Julio L. Lancelotti Luciana M. Pozzi Pablo M. Yorio María C. Diéguez Miguel A. Pascual 《水产资源保护:海洋与淡水生态系统》2010,20(1):1-8
- 1. Conflicts between habitat use and conservation are inherent to the management of wetlands. A major challenge for their management is to preserve habitat while addressing the demands from multiple users. In southern Patagonia (Argentina), a growing aquaculture activity based on rainbow trout introductions in shallow lakes is generating concerns about the effects on the waterbird fauna, including some endemic species.
- 2. Generalized linear models (GLM) were used to analyse data on the endemic hooded grebe (Podiceps gallardoi) collected over a diverse set of lakes to: (1) build presence‐absence models as a function of environmental variables; (2) assess current and potential overlap with trout aquaculture; (3) explore the power of alternative lake assignment algorithms based on habitat variables to segregate critical habitat and aquaculture activities; and (4) explore the correlation between the probability of grebe presence and their abundance in given lakes.
- 3. Hooded grebe presence is clearly correlated with macrophyte cover, lake area, and water conductivity. Medium size lakes, with a combination of emerging macrophytes, adjacent to open water areas had the highest probability of both hooded grebe presence and abundance.
- 4. Different lake allocation scenarios are identified that could grant significant protection to hooded grebes without substantial losses for trout producers. The a priori probability to hold hooded grebe, assigned by the model based on lake characteristics, provides a tool that can be used by managing authorities to derive precautionary management rules to regulate aquaculture and to preserve primary hooded grebe habitat. Copyright © 2009 John Wiley & Sons, Ltd.
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Cristina Trigal‐Domínguez Camino Fernández‐Aláez Francisco García‐Criado 《水产资源保护:海洋与淡水生态系统》2009,19(7):786-796
- 1. Habitat heterogeneity has many implications in ecological assessment studies. On one hand it provides varying niches for organisms, increasing diversity. On the other hand, the inherent spatial variability of structurally complex systems may overlap with ecological condition making it difficult to disentangle the effects of perturbation. This study investigated the combined and single effects of habitat and pond condition on the macroinvertebrate assemblages of 35 ponds located in north‐west Spain and spanning a range of water quality and habitat characteristics.
- 2. Macroinvertebrate communities and several environmental variables were sampled in the summer of 2004 or 2003. Samples were collected from four dominant habitats (vegetated shores, shores without vegetation, submerged vegetation, bare sediments) following a time‐limited sampling. Non‐metric multidimensional scaling and two‐way crossed ANOSIM were used to investigate the taxonomic and functional differences in macroinvertebrate assemblage structure among habitats (four types) and pond conditions (optimal, good, moderate, poor, very poor). To investigate the individual and combined effects of pond condition and habitat on several diversity measures GLM models were used. In addition, the accuracy of two sampling designs — stratified and multihabitat — was compared using the CVs of seven macroinvertebrate attributes.
- 3. Results showed that macroinvertebrate communities differed significantly, albeit weakly, among habitat types and pond condition categories. In particular, the abundance of several Chironomidae genera, rarefied richness and Shannon index decreased both in perturbed systems and bare sediments, whereas no marked differences occurred between shores and submerged vegetation.
- 4. We suggest that a multihabitat approach together with the use of community attributes not (or slightly) affected by habitat type will provide more comparable results across ponds than a stratified approach or observation of the whole community, especially in ponds where degradation leads to habitat loss.Copyright © 2009 John Wiley & Sons, Ltd.
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Distribution,habitat associations and conservation implications of Sri Lankan freshwater terrapins outside the protected area network 
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下载免费PDF全文 Suranjan Karunarathna A. A. Thasun Amarasinghe Sujan Henkanaththegedara Thilina Surasinghe Majintha Madawala Dinesh Gabadage Madhava Botejue 《水产资源保护:海洋与淡水生态系统》2017,27(6):1301-1312
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- 1. Detailed knowledge of habitat requirements is particularly relevant to the conservation of rare and threatened fish species because habitat fragmentation and loss are usually the major threats to species with limited distributions and restricted habitat requirements, and habitat restoration is typically the first step in species' recovery plans. This paper documents the macro‐, meso‐ and microhabitat habitat associations of a small threatened percichthyid, the Oxleyan pygmy perch, Nannoperca oxleyana, in south‐eastern Queensland and north‐eastern New South Wales (NSW), Australia.
- 2. The species' range encompasses approximately 530 km of coastline from Coongul Creek on Fraser Island, Queensland (25° 16′S, 153° 09′E) south to Tick Gate Swamp near the township of Wooli, NSW (29° 54′S, 153° 15′E). It is confined primarily to dystrophic, acidic, freshwater systems draining through sandy coastal lowlands and Banksia ‐ dominated heath ecosystems.
- 3. Both lentic and lotic environments provide habitat for N. oxleyana but the species is found only in slow‐flowing pools and backwaters of river channels and tributaries as well as in swampy drainages, lakes, ponds and dams.
- 4. Trapping studies found that an abundance of structural aquatic habitat was a defining microhabitat feature either in the form of beds of emergent or submerged plants or the presence of steep/undercut banks fringed with the semi‐submerged branches and fine rootlets of riparian vegetation. When present, leaf litter and snags also provided cover.
- 5. Recent and historical survey data suggest that human activities have had a significant influence on contemporary species presence/absence patterns and may have been responsible for the prominent gaps within the Queensland‐NSW distribution of N. oxleyana.
- 6. The distinctive relationships of N. oxleyana with features of aquatic habitat at the macro‐, meso‐ and microhabitat scale demonstrate principles applicable to any study focused on the conservation of an endangered fish species.
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Linking small pelagic fish and cetacean distribution to model suitable habitat for coastal dolphin species,Delphinus delphis and Tursiops truncatus,in the Greek Seas (Eastern Mediterranean) 下载免费PDF全文
下载免费PDF全文 Marianna Giannoulaki Evangelia Markoglou Vasilis D. Valavanis Paraskevi Alexiadou Anna Cucknell Alexandros Frantzis 《水产资源保护:海洋与淡水生态系统》2017,27(2):436-451
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Negative effect of zebra mussels on foraging and habitat use by lake sturgeon (Acipenser fulvescens)
- 1. Lake sturgeon (Acipenser fulvescens) are threatened or endangered throughout much of their range. Juvenile sturgeon utilize sandy and silty habitats extensively during their growth. Invasive zebra mussels change the nature of sandy and silty habitats because they settle on and coat the habitat with the shells of living and dead individuals. The potential impacts of this increased habitat complexity on lake sturgeon is unknown.
- 2. Juvenile lake sturgeon habitat choice was assessed in laboratory experiments, and zebra mussel impact on the foraging success of juvenile lake sturgeon on three different prey species was measured.
- 3. Sturgeon foraging on chironomids was virtually eliminated by 95% zebra mussel cover of the sand floor of the foraging arena, and 50% cover reduced foraging significantly. Foraging on more mobile prey items (amphipods and isopods) was essentially eliminated by either 95% or 50% zebra mussel cover of the arena floor. In habitat choice experiments, sturgeon avoided the zebra‐mussel‐covered habitat more than 90% of the time.
- 4. This combination of zebra mussel avoidance and reduced foraging in the presence of zebra mussels may be detrimental to sturgeon restocking programmes utilizing smaller sturgeon in zebra‐mussel‐infested waterways.