Using ecological trajectories to track long-term taxonomic and functional changes in benthic shallow soft-bottom communities (Bay of Saint-Brieuc,English Channel)     

Anthony Sturbois  Gaëtan Cormy  Alexandre Le Moal  Gauthier Schaal  Caroline Broudin  Eric Thiébaut  Alain Ponsero  Patrick Le Mao  Auriane Jones  Pascal Riera  Olivier Gauthier  Nicolas Desroy 《水产资源保护:海洋与淡水生态系统》2021,31(11):3013-3033

1. Taxonomic and functional trajectories of benthic assemblages were studied in shallow soft-bottom sediments in the bay of Saint-Brieuc (Western English Channel). Changes were assessed at different spatial and temporal scales using a macrobenthic dataset based on 38 stations sampled in 1987 and 2019, coupled with data from one station sampled annually between 2005 and 2019 as part of the European Water Framework Directive monitoring programme.
2. Taxonomic trajectories indicated 1) changes in the structure and distribution of benthic assemblages, 2) an homogenization of the assemblages, and 3) significant functional shifts.
3. Fishing activities and nutrient enrichment are probably strong drivers of the observed changes, as suggested by the higher mortality rate of fragile, flexible, tubiculous and burrowing species, and the increase in the abundance of opportunistic species in the assemblages. Certain populations of macroinvertebrates seem jointly controlled by climate change and by the aforementioned local factors of disturbance.
4. The Community Trajectory Analysis framework appears as a new and interesting method to track ecological changes in marine ecosystems by measuring change with respect to a baseline state, to help define ecological recovery (station returning to the initial ecological state) and departure (station presenting increased changes over time), and to analyse trajectory similarity.
5. According to the degradation of habitat over time, we identify the need for the implementation of knowledge-based conservation strategies, especially within Natura 2000 sites.

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Ditch communities: a major contributor to floodplain biodiversity     

Patrick D. Armitage  Krzysztof Szoszkiewicz  John H. Blackburn  Ian Nesbitt 《水产资源保护:海洋与淡水生态系统》2003,13(2):165-185

• 1. Chalk stream floodplains are extensively managed and the high degree of connectivity associated with water meadows has been severely reduced. The main contributor to aquatic biodiversity is perceived to be the river itself. Ditches in these areas have been largely ignored as a contributor to total diversity.
• 2. Separate surveys of instream, bankside and ditch macroinvertebrates in a small area of floodplain provided a unique opportunity to assess the relative contribution of each locality to total aquatic diversity. The fauna and flora of a ditch on the lower River Frome floodplain was examined and compared with studies of adjacent bankside and instream habitat. A total of 145 macroinvertebrate taxa and 61 plant species were recorded from the ditch. Faunal abundance and richness were positively related to the diversity of aquatic plants. The ditch showed a clear linear trend in community type that appeared to be partly related to the acidic seepage from tertiary deposits at the source and percentage cover of vegetation.
• 3. There were large differences in the numbers of taxa collected in ditch, bankside, instream mesohabitat and RIVPACS surveys. Of the total 202 taxa recorded in the four surveys, the ditch contributed 59 unique taxa with 25 from the bankside and two and three from the mesohabitat and RIVPACS surveys, respectively.
• 4. The large contribution of the Rushton Ditch to aquatic biodiversity on the floodplain is due to three main factors: the chemically different and slow‐flowing environment, the connection to the main river, and a management regime which has halted hydroseral succession at a point where vegetation structure is for the most part open and able to support a wide range of ecological niches. The maintenance of these conditions requires sensitive management and further knowledge of the needs and interactions of faunal communities with vegetation.

Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Effects of weaning age and diets on ontogeny of digestive activities and structures of pikeperch (<Emphasis Type="Italic">Sander lucioperca</Emphasis>) larvae     

Neila Hamza  Mohamed Mhetli  Patrick Kestemont 《Fish physiology and biochemistry》2007,33(2):121-133

Growth and ontogeny of digestive function were studied in pikeperch (Sander lucioperca) larvae weaned on artificial food at different ages. Three weaning treatments initiated respectively on day 9 (W9), day 15 (W15) or day 21 (W21) post-hatching (p.h.) were compared with a control group, fed Artemia nauplii from first feeding until the end of the rearing trial on day 36 p.h. The digestive enzyme activities and the ontogeny of digestive structures were investigated using enzymatic assays and histological methods. Growth of pikeperch larvae was significantly affected by precocious weaning. Pancreatic (trypsin and amylase) and intestinal (leucine-alanine peptidase, leucine aminopeptidase N and alkaline phosphatase) enzyme activities were detected from hatching onwards, increased at the moment of first feeding and then decreased. Pepsin secretion occurred at day 29 p. h. only, concurrently with the stomach development and differentiation of gastric glands. In the early weaning group (W9) the maturation process of intestinal enterocytes seems to be impaired and/or delayed and several signs of malnutrition were recorded. Except for alkaline phosphatase activity, no differences in enzyme activities and development of digestive structures were observed among the control, W21, and W15 groups. Moreover, at the end of the experiment, no differences in proteolytic activities were observed among larvae from the different treatments, indicating that, in surviving individuals, the digestive structures were properly developed and the larvae had acquired an adult mode of digestion. Based on the artificial diet used, our results suggested that pikeperch larvae can be weaned from day 15 p.h. without significant adverse effect on digestive capacities (except for alkaline phosphatase) or development of digestive tract, while earlier weaning impaired the onset of the maturation processes of the digestive system, both in terms of morphological structures and enzymatic activities.  相似文献   

Tyrosine hydroxylase activity and dopamine turnover of rainbow trout (Oncorhynchus mykiss) brain: the special status of the hypothalamus   总被引：1，自引：0，他引：1  

Boris Linard  Sanae Bennani  Patrick Jego  Christian Saligaut 《Fish physiology and biochemistry》1996,15(1):41-48

The dynamics of catecholamine (CA)-synthesis enzymes have been poorly studied in fish. Tyrosine hydroxylase (TH), the rate-limiting enzyme of CA synthesis has been only studied inin vitro conditions. In the present report thein vivo CA synthesis and the CA metabolism were studied in different regions of the forebrain of the rainbow trout. Levels of norepinephrine (NE), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and the rate of accumulation of 3,4-dihydroxyphenylalanine (DOPA) were determined by HPLC following a treatment with hydroxybenzylhydrazine (NSD), a potential inhibitor of DOPA decarboxylase. Kinetics of the accumulation of DOPA and of the decline of DOPAC were in agreement with those found in rat, evidencing that the accumulation of DOPA following NSD can be used in trout to quantify thein vivo enzymatic activity of tyrosine hydroxylase. Experiments using treatment with NSD or with methyl-p-tyrosine reached a same conclusion: the DA neuronal activity in trout is much higher than NE neuronal activity. However, the hypothalamus had high DA levelsvs. lowin vitro andin vivo TH activities and exhibited a low CA turnover.  相似文献   

How well does a botanical garden collection of a rare palm capture the genetic variation in a wild population?   总被引：1，自引：0，他引：1  

Sandra Namoff  Javier Francisco-Ortega  Larry R. Noblick  M. Patrick Griffith 《Biological conservation》2010,143(5):1110-1117

Conservation is increasingly central to the botanic garden mission. Living plant collections are important components of conservation. Critical evaluation of living conservation collections with population genetic analysis can directly inform ex situ conservation strategy. Here, we quantify the degree of genetic variation captured through a population-based collection protocol, and explore optimal sampling for ex situ conservation. An extensive living collection derived from one population of Leucothrinax morrisii (Arecaceae) provided a model system. We compared 58 specimens from the ex situ collection with 100 individuals from throughout the parent population via 6 ISSR loci. Random bootstrapped resamples of the data were made to model differently structured ex situ collections. Mean diversity (He) differed little between the collection (0.204) and the population (0.216), and genetic distance (D) was very close (0.036). Very few private alleles were found between the collection and the population. Allelic capture, as measured by percent of private alleles, was greater than 94%. Resampled collections of different sizes captured from 48% to 94% of alleles. Pairwise comparison of bootstrapped resamples suggests that increasing the representation of half-sibling groups does not significantly increase allele capture. Increase in allele capture with increasing sample size is greatest at low resample sizes, and showed diminishing returns as resample size increased. No appreciable increase in allele capture was gained through maintaining different half-sibling groups. These data inform sampling for ex situ conservation purposes, and recommend sample sizes of at least 15 individuals, with the upper limit based on resources.  相似文献   

Comparison of Docosahexaenoic Acid (22:6n-3) Levels in Various Artemis Strains during Enrichment and Subsequent Starvation     

Kyungmin  Han  Inge  Geurden  Patrick  Sorgeloos 《Journal of the World Aquaculture Society》2000,31(3):469-475

Abstract.— The aim of this study was to compare the levels of docosahexaenoic acid (DHA, 22:6n-3) in three different bisexual and one parthenogenetic strains of Artemia after enrichment. Freshly-hatched nauplii from A. franciscana (Great Salt Lake, USA), A. sinica (Yimeng, P. R. China), A. persimilis (Argentina), and A. parthenogenetica (Tanggu, P. R. China) were enriched with a purified lipid emulsion containing 95% DHA ethyl esters (% total fatty acids) and subsequently starved. All strains had very low initial DHA levels (< 0.3 mg/g dry weight). Initial eicosapentaenoic acid, 20:5n-3 (EPA) levels were high in A. parthenogenetica (18.2 mg/g dry weight) as compared to those in the other strains (4.6-8.5 mg/g dry weight). After 24-h enrichment, A. sinica contained the highest DHA level (37.0 mg/g dry weight) as well as the highest DHA/ EPA ratio (3.7). The lowest DHA enrichment levels were found in A. franciscana and A. parthenogenetica (26.3 and 22.7 mg/g dry weight, respectively). During the subsequent 24-h starvation period, the contents of DHA decreased rapidly in all strains, whereas EPA levels remained relatively stable. This indicates the high catabolism of DHA for energy production, the relative conservation of EPA, and possibly a partial bioconversion of DHA to EPA during the starvation period in each species.  相似文献   

IMAGING DIAGNOSIS: THE ABDOMINAL AIR-VASCULOGRAM IN A DOG WITH SPLENIC TORSION AND CLOSTRIDIAL INFECTION     

Lorrie  Gaschen  DVM  PHD  Patrick  Kircher  DVM  Claudio  Venzin  DVM  Karin  Hurter  DVM  Johann  Lang  PD  DVM 《Veterinary radiology & ultrasound》2003,44(5):553-555

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Effects of stocking density on the survival, growth, size variation and condition index of juvenile rabbitfish Siganus rivulatus     

I. Patrick Saoud  Joly Ghanawi  Nada Lebbos 《Aquaculture International》2008,16(2):109-116

Spinefoot rabbitfish, Siganus rivulatus, is an economically important species of herbivorous fish that is relatively easy to rear and thus considered to be suitable for aquaculture. Juveniles are generally reared in nursery systems before being stocked into growout cages or ponds. We report here our evaluation of the effects of stocking density on the survival, growth, feed efficiency and condition index of S. rivulatus juveniles in nursery tanks. The experiment was conducted in a recirculating system of twelve 52-l aquaria connected to a biological filter and a sand filter. Juvenile fish (average weight 6.5 g) were stocked into aquaria at four stocking densities (10, 20, 30, and 40 fish/aquarium) with three replicate aquaria per treatment. Diet was provided at 3% body weight daily divided into two feedings. Fish were weighed weekly for 8 weeks and the diet increased accordingly. Survival was greater than 95% in all treatments, with no significant differences observed among treatments. There were also no differences in specific growth rate (SGR 2.12–2.27) of the fish among treatments. Growth rate was linear during the 8 weeks in all treatments, and harvested biomass increased proportionally to stocking density (198, 401, 600 and 785 g per increasing stocking density, respectively). Feed efficiency (FE 0.67–0.71) of the fish did not vary significantly among treatments. The coefficient of variation was high (35–41%) among the harvested fish, but it also did not differ significantly among treatments. The final condition indices of the fish in all treatments were similar to each other but significantly greater than the initial values (P < 0.05). The results suggest that there is no apparent effect of stocking density at the levels tested on the survival and growth of juvenile rabbitfish.  相似文献   

ENDOSCOPIC ULTRASOUND INSTRUMENTATION, APPLICATIONS IN HUMANS, AND POTENTIAL VETERINARY APPLICATIONS     

Lorrie  Gaschen  DVM  PhD  Patrick  Kircher  DVM  Johann  Lang  DVM  PD 《Veterinary radiology & ultrasound》2003,44(6):665-680

Endoluminal scanning under endoscopic guidance, or endoscopic ultrasonography (EUS), has become the most significant advance for imaging the gastrointestinal (GI) tract wall and contiguous organs in the past 20 years. It was originally designed to overcome the limitations in humans to imaging the abdominal organs transabdominally, such as large penetration depths and GI air. This imaging modality provides detailed images of pathological processes both within and outside of the GI wall since a high-frequency transducer can be brought into close proximity with the target regions. It has found most success in humans for the staging of lung, gastric, and esophageal cancer, the detection of both lymphatic and hepatic metastases, and diagnosis of pancreatitis and pancreatic cancer, as well as achieving an important role in interventional and therapeutic procedures. The EUS examination can be performed to examine both the thorax and abdomen in animals when both conventional transthoracic or transabdominal ultrasound are inadequate due to intervening air, bone, large penetration depths, or obesity. The echoendoscope is similar to a conventional endoscope but has an ultrasound transducer at its tip. Both radial and linear multifrequency scanners are available. Linear scanners allow fine-needle aspiration (FNA) of the bowel wall or extraluminal structures. Transducer coupling is either by direct mucosal contact or by inflation of a water-filled balloon surrounding the transducer. Current thoracic applications for EUS in veterinary medicine include examination of the mediastinum, bronchial lymph nodes, esophagus, and pulmonary lesions as well as FNA of pulmonary masses. Abdominal applications include examination of both pancreatic limbs and the liver, including portosystemic shunts, detection of lymphadenomegaly, and examination of the gastric wall, duodenum, and jejunum. Other potential applications in dogs and cats include tumor staging and intrapelvic ultrasound.  相似文献   

Growth and Feed Utilization of Captive Wild Subadult Black Sea Bass Centropristis striata Fed Practical Diets in a Recirculating System     

Kimberly A.  Copeland  Wade O.  Watanabe Patrick M.  Carroll 《Journal of the World Aquaculture Society》2002,33(2):97-109

The effects of four practical diets on growth, feed utilization, and body composition of wild‐caught juvenile and subadult black sea bass Centropristis striata (316 ± 113 g =±± SD) were compared for 221 d in a recirculating tank system consisting of 12 2,660‐L tanks. Salinity averaged 33.5 ppt and temperature averaged 20.9 C but vaned from 12 to 27.1 C. Diets differed in crude protein (CP) and crude lipid (CL) as follows: 1) low CP (44.0%), low CL (11.4%) trout diet; 2) low CP (44.8%), high CL (15.0%) trout diet; 3) midlevel CP (47.9%), midlevel CL (12.8%) Bounder diet; and 4) high CP (53.9%), high CL (15.1%) marine finfish diet. Energy: protein ratios (E: P) were 44.6, 45.3, 41.8, and 39.1 W/g. Survival to 221 d on all diets was 100%. Significant (P < 0.05) differences in growth rates were observed among diets. Final weights were higher for midlevel and high CP diets 3 and 4 (1,051 and 1,013 g) than for low CP diet 1 (873 g). Relative growth rate (RGR, % total increase in weight), specific growth rate (SGR, % increase in body weight/d), and daily weight gain (DWG, g/d) were higher for higher CP diets 3 and 4 (RGR = 223 and 221; SGR = 0.53; DWG = 3.28 and 3.16), than for low CP diet 1 (RGR = 181; SGR = 0.47; DWG = 2.54). There were no significant differences between initial and final whole body protein and fiber content among diets. Lipid and gross energy levels significantly increased (P < 0.0001) in all treatments while moisture levels significantly decreased (P < 0.001). Although these differences were not significant, feed conversion ratio (FCR = dry weight fed/wet weight gain) was lower for fish given midlevel CP diet 3 (1.49) and high CP diet 4 (1.52) than for those fed low CP diets 1 and 2 (1.60 and 1.62). Protein efficiency ratios (PER = weight gain/weight protein fed) (1.43 to 1.24), apparent net protein retention (ANPR = weight protein gain/weight protein fed) (20 to 25%), and apparent net energy retention (ANER = energy gain/energy fed) (53.3 to 56.8%) were not significantly different among treatments. The midlevel CP (50%), midlevel CL (12%) diet maximized growth rates and was also significantly less expensive per kg fish weight produced ($1.40) than the high CP diet ($1.94) which produced the second highest growth rates. These results demonstrated that wild‐caught black sea bass can be successfully reared in recirculating tanks from juvenile to marketable sizes with high survival and with good feed conversion and growth on commercially prepared diets with a wide range of protein and lipid levels.  相似文献