תודה מיוחדת ממחלקת הסביבה St. Regis מוהוק, מדגרת דגים Welaka הלאומי, דגים בארה&quot;ב יחידת המחקר שירות בטבע, באוניברסיטת דרום אילינוי, דגים בארה&quot;ב מרכז הדיג Northeast שירות בטבע, סטרלינג קוויאר, אוניברסיטת קליפורניה-דיוויס, גאריסון סכר לאומי דגים מדגרה, מדגרת הדגים הלאומית Bluff דובים, וארה&quot;ב דגים וחיות בר שירות פנמה סיטי דיג משאבי משרד עזרו באספקת חדקן עבור פרויקט זה. מאמר זה הוא תרומה 2013 במרכז מדע האגמים הגדול USGS.

הערה חשובה: בשל מעמדם המוגן של כל המינים של חידקן בארצות הברית, מאפשרת לרכוש ולטפל דגים התקבלו לפני הליך מעבדה. כל הדגימות נרכשו ממקורות מדגרה לפרסם מורטם בשל סיבות טבעיות ועל מסולק בהתאם לנוהל השגרתי. 1. הכנת הדגימה <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> לפני חתכים בכל שכבת פגר חדקן על צידו באמצעות סרט מדידה כדי למדוד אורך כולל של החוטם אל קצה הזנב עד המ&quot;מ 1 הקרוב. (איור 1 א) </li><li style=";text-align:right;direction:rtl"> לשקול פגר חדקן בסולם tared אל הגרם 1 הקרוב. הערכת פגר לכל תגיות או סימנים ולהקליט חיצוניים. </li></ol> 2. אֶבֶן הַאוֹזֶן הפקה <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> ביצוע חתך אנכי עם סכין פילה גדול בין בסיס הגולגולת ואת scute הגבה הראשונה דרך הגוף להפריד את הראש מהגוף (האיור 1B). לאחר הסרת הראש, turn הראש כך הפה הוא פונה כלפי מעלה (איור 1 ג). </li><li style=";text-align:right;direction:rtl"> הסר הרקמות הרכות של הפה הזימים באמצעות סכין פילה לחתוך לאורך הצד הגחוני של הגולגולת (איור 1D). עושים חתך עם מסור חשמלי עצם מקצה החוטם לבסיס הגולגולת כדי לחצות את הראש לחלוטין (איור 1E). הפרד את שני חצי ביד כדי לחשוף את חלל המוח (איור 2 א). </li><li style=";text-align:right;direction:rtl"> סר וזורק משנה המוח (תיבת האדום משמאל) עם מלקחיים כדי להציג תעלות בצורה חצי עיגול (תיבת האדום מימין) בתוך חלל המוח (איור 2 ב). </li><li style=";text-align:right;direction:rtl"> הסר סחוס תעלה חצי עגול מ חלל המוח עם מלקחיים (איור 2 ג). בזהירות לנקב סחוס תעלה חצי עגול עם קצה מלקחיים ולהסיר אֶבֶן הַאוֹזֶן (איור 2 ד). הסר את אֶבֶן הַאוֹזֶן (מבנה גרמי קשה בתוך סחוס) עם מלקחיים מן הסחוס תעלה חצי עגול (איור 2E) </strong&gt;. </li><li style=";text-align:right;direction:rtl"> חזור על שלבים 2.3 - 2.4 ל להסיר אֶבֶן הַאוֹזֶן מן החצי השני של הגולגולת. </li><li style=";text-align:right;direction:rtl"> טובל את otoliths באתנול 92% במשך 5 שניות כדי להסיר כל סחוס. otoliths מקום ב בקבוקון הנצנץ 25 מ&quot;ל פתוח להתייבש במשך 24 שעות. </li></ol>

<ol>
	<li>Auer, N. A., LeBreton, G. T. O., Beamish, F. W. H., McKinley, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conservation.">Conservation.</a> Sturgeons and Paddlefish of North America. 27, 252-276 (2004).</li><li>Campana, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy,+precision+and+quality+control+in+age+determination,+including+a+review+of+the+use+and+abuse+of+age+validation+methods).">Accuracy, precision and quality control in age determination, including a review of the use and abuse of age validation methods).</a> Journal of Fish Biology. 59, 197-242 (2001).</li><li>Bruch, R. M., Campana, S. E., Davis-Foust, S. L., Hansen, M. J., Janssen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lake+Sturgeon+age+validation+using+bomb+radiocarbon+and+known-age+fish.">Lake Sturgeon age validation using bomb radiocarbon and known-age fish.</a> Transactions of the American Fisheries Society. 138, 361-372 (2009).</li><li>Baremore, I. E., Rosati, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+validated,+minimally+deleterious+method+for+ageing+sturgeon.">A validated, minimally deleterious method for ageing sturgeon.</a> Fishery Bulletin. 112, 274-282 (2014).</li><li>Stevensen, J. T., Secor, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age+determination+and+growth+of+Hudson+River+Atlantic+sturgeon,+Acipenser+oxyrhynchus.">Age determination and growth of Hudson River Atlantic sturgeon, Acipenser oxyrhynchus.</a> Fishery Bulletin. 97, 153-166 (1999).</li><li>Brennan, J. S., Cailliet, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+age-determination+techniques+for+white+sturgeon+in+California.">Comparative age-determination techniques for white sturgeon in California.</a> Transactions of the American Fishery Society. 118, 296-310 (1989).</li><li>Rossiter, A., Noakes, D. L. G., Beamish, F. W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+of+age+estimation+for+the+lake+sturgeon.">Validation of age estimation for the lake sturgeon.</a> Transactions of the American Fisheries Society. 124, 777-781 (1995).</li><li>Chalupnicki, M. A., Dittman, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=North+American+Sturgeon+Otolith+Morphology.">North American Sturgeon Otolith Morphology.</a> Copeia. , 260-266 (2016).</li><li>Secor, D. H., Dean, J. M., Laban, E. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Manual for otolith removal and preparation for microstructural examination. , (1991).</li></ol>

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הסקירה של שיטה חלופית של לחילוץ otoliths מגוויות חדקן כבר מפורטת. חשוב לציין כי תשומת לב מיוחדת צריכה את המיקום חתך לרוחב על קו האמצע של הגולגולת כדי לחצות את הגולגולת שווה כדי לוודא שלא ניזוק אל otoliths במהלך לנתיחה. אם החתך הוא לא עמוק מספיק כדי לחצות את הגולגולת לגמרי זה י?...

חדקן (Acipenseridae) אוכלוסיות ברחבי העולם כבר בירידה במשך יותר ממאה שנה בשל ההשפעות כולל אובדן בית הגידול, קיטוע האוכלוסייה, ואת overfishing כך אוכלוסיות רבות מוגנים על ידי חוקי המדינה הפדרלי 1,2. סוכנויות ניהול ברחבי ארה&quot;ב והעולם זיהו חדקן כמין יעד לשיקום והתאוששות 1. מאפייני האוכלוסייה (צמיחה, גיוס, דיאטה) של אוכלוסיות חדקן ביותר נחקרו כדי להבין את ההיסטוריה הביולוגיה הבסיסית לחיים טובים יותר מאפיינים 1. בשל מעמדם המוגן של רוב אוכלוסיות חידקן, הערכת גיל קשה באוכלוסיות קטנות מאוימות שבו אף קרבה או ניזק ליחידים היא מוצדקת. הפקת מבנים גרמיים לצורך הערכת גיל וניתוח צמיחה הייתה שימוש טכניקה נפוצה 3 .the סעיפי ray סנפיר כדי לקבוע גיל sturgeעל הפכה שיטה קטלנית מעשית, אך אימות של הטכניקה הוגבלה וגיל יכול להיות מאוד קשה לפענח אצל אנשים מבוגרים (&gt; 15 שנים) 4. החוקרים להעריך את השימוש במבנים הגרמיים מרובים חדקן לשימושם אימות גיל המפרץ חדקן (desoti חדקן oxyrinchus) 5, אטלנטיק חדקן (א o. Oxyrinchus) 6, לבן חדקן (transmontanus א) 7, ואגם חדקן (א fluvescens) 8 למסקנה כי ray סנפיר החזה השולי הראשון ספק את הגיל המדויק ביותר, אך מדענים קובע הליך פולשני זה להיות מזיקות פרטים גדולים יותר. נכון לעכשיו, קיימת ההתפתחות של שימוש במטריצות צורת אֶבֶן הַאוֹזֶן להבחין בין מיני חדקן בצפון אמריקה עם שיעור גבוה מאוד של הצלחה 9. פרטים על תהליך ההסרה של אֶבֶן הַאוֹזֶן עם חתך רוחבי מגבה בבסיס הגולגולת הוא אֶבֶן הַאוֹזֶן נפוץ נוסףשיטת ction עיון בספרות העלה ופירט בבירור אל Secor et. (1991) 10. עם זאת, שיטה זו היא קשה ליישם על חדקן שיש גולגולות עבות מאוד עם otoliths כי הם קטנים ועדינים היו נשברים ומפרקים. סקירה נוספת של הספרות מראה שום מתודולוגיה מפורטת שנייה של תהליך הסרת אֶבֶן הַאוֹזֶן עבור חדקן. מטרת נייר זה הייתה לפרט שיטה חלופית של לחילוץ otoliths מ חדקן ידי הזנת חלל המוח מצד הגחון.

<table><tbody><tr><td>Measuring Board</td><td></td><td></td><td>Metric meter stick is preferred</td></tr><tr><td>Weighing scale</td><td></td><td></td><td></td></tr><tr><td>Filleting Knife</td><td></td><td></td><td></td></tr><tr><td>Scalpel</td><td></td><td></td><td></td></tr><tr><td>Forceps</td><td></td><td></td><td></td></tr><tr><td>Sample vials</td><td></td><td></td><td>25 ml scintillation vials work well</td></tr></tbody></table>

alternative method of removing otoliths from sturgeon

חילוץ otoliths (עצמות אוזן) מדגים כי יש גולגולות עבות מאוד יכול להיות זמן רב קשה מאוד. המנהג הנפוץ של ביצוע חתך אנכי רוחבי על החלק העליון של הגולגולת עם יד או במסור חשמלי עלול לגרום נזק אֶבֶן הַאוֹזֶן אם לא מבוצע כהלכה. דגי (Acipenseridae) הם משפחה אחת בפרט שיש גולגולת מאוד גדול ועבה. שיטת מעבדה חדשה הנכנסת חלל המוח מצד הגחון של הדג על מנת לחשוף את otoliths הייתה קלה יותר מאשר שיטות חילוץ אֶבֶן הַאוֹזֶן אחרות למצוא בספרות. שיטות ביקורת בספרות מיועדות בתחום והם יעילים יותר עיבוד כמויות גדולות של דגים מהר. עם זאת, טכניקה חדשה זו נועדה להיות יותר מתאים במעבדת הגדרה כאשר הזמן אינו לחיצת חילוץ מוצלח מכל דגימה הוא קריטי. ההצלחה של מציאה והסרת otoliths באמצעות טכניקה זו היא מאוד גבוהה לא להתפשר על היםtructure בכל דרך. טכניקה חלופית זו ישימה מיני דגים דומים אחרים לחילוץ otoliths.

הגודל הבוגר חדקן ברחבי העולם משתנה מאוד אבל המיקום של otoliths עולה בקנה אחד. שימוש סכין פילה חד נמצא להסיר את הרקמות הרכות של הפה לראות בקלות באיור 1D. מסור עצם חשמלי הוא הכלי המועדף עבור החתך לרוחב כדי לחשוף את חלל המוח באיור 1E. עם זאת, ?...

Watch this Scientific Journal Video about Alternative Method of Removing Otoliths from Sturgeon at JoVE.com

Alternative Method of Removing Otoliths from Sturgeon

The goal of the protocol is to show an effective method to extract the otoliths from sturgeon carcasses.

שיטה חלופית של הסרת Otoliths מ חדקן

Extracting the otoliths (ear bones) from fish that have very thick skulls can be difficult and very time consuming. The common practice of making a ...

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8.4K Views.  Great Lakes Science Center. The goal of the protocol is to show an effective method to extract the otoliths from sturgeon carcasses. 

Video: Alternative Method of Removing Otoliths from Sturgeon

A Flow-through Exposure System for Evaluating Suspended Sediments Effects on Aquatic Life

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory by using pumps and automating delivery of sediment and water to simulate suspension of sediment. FLEES data are used to develop exposure-response curves between the effects on aquatic organisms and suspended sediment concentrations at the desired exposure duration. The effects data are used to evaluate management practices used to reduce the interactions between aquatic organisms and anthropogenic causes of suspended sediments. The FLEES is capable of generating total suspended solids (TSS) concentrations as low as 30 to as high as 800 mg/L, making this system an ideal choice for evaluating the effects of TSS resulting from many activities including simulating low ambient levels of TSS to evaluating sources of suspended sediments from dredging operations, vessel traffic, freshets, and storms.

A robust and flexible flow-through exposure system designed to maintain sediment in suspension is presented. The system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory.

מערכת חשיפת זרימה דרך להערכת מושעה משקעים השפעות על חיים ימיים

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended ...

Necropsy-based Wild Fish Health Assessment

Anthropogenic influences from increased nutrients and chemical contaminants, to habitat alterations and climate change, can have significant effects on fish populations. Adverse effects monitoring, utilizing biomarkers from the organismal to the molecular level, can be used to assess the cumulative effects on fishes and other organisms. Fish health has been used worldwide as an indicator of aquatic ecosystem health. The necropsy-based fish health assessment provides data on visible abnormalities and lesions, parasites, condition and organosomatic indices. These can be compared by site, season and sex, as well as temporally, to document change over time. Severity ratings can be assigned to various observations to calculate a fish health index for more quantitative assessment. A drawback of the necropsy-based assessment is that it is based on visual observations and condition factors, which are not as sensitive as tissue and subcellular biomarkers for sublethal effects. Additionally, it is rarely possible to identify causes or risk factors associated with observed abnormalities. So, for instance a raised lesion or "tumor" on the fins, lips or body surface may be a neoplasm. However, it could also be a response to a parasite, chronic inflammation or hyperplasia of normal cells in response to an irritant. Conversely, neoplasms, certain parasites, other infectious agents and many tissue changes are not visible and so may be underestimated. However, during the necropsy-based assessment, blood (plasma), tissues for histopathology (microscopic pathology), genomics and other molecular analyses, and otoliths for aging can be collected. These downstream analyses, together with geospatial analyses, habitat assessments, water quality and contaminant analyses can all be important in comprehensive ecosystem evaluations.

The health of wild fishes can be used as an indicator of aquatic ecosystem health. Necropsy-based fish health assessments provide documentation of visible lesions or abnormalities, data used to calculate condition indices as well as the opportunity to collect tissues for microscopic evaluation, gene expression and other more in-depth analyses.

הערכת הבריאות מבוסס necropsy דגים פראי

Anthropogenic influences from increased nutrients and chemical contaminants, to habitat alterations and climate change, can have significant effects on ...

Modeling the Size Spectrum for Macroinvertebrates and Fishes in Stream Ecosystems

The size spectrum is an inverse, allometric scaling relationship between average body mass (M) and the density (D) of individuals within an ecological community or food web. Importantly, the size spectrum assumes that individual size, rather than species&#8217; behavioral or life history characteristics, is the primary determinant of abundance within an ecosystem. Thus, unlike traditional allometric relationships that focus on species-level data (e.g., mean species&#8217; body size vs. population density), size spectra analyses are &#8216;ataxic&#8217; &#8211; individual specimens are identified only by their size, without consideration of taxonomic identity. Size spectra models are efficient representations of traditional, complex food webs and can be used in descriptive as well as predictive contexts (e.g., predicting responses of large consumers to changes in basal resources). Empirical studies from diverse aquatic ecosystems have also reported moderate to high levels of similarity in size spectra slopes, suggesting that common processes may regulate the abundances of small and large organisms in very different settings. This is a protocol to model the community-level size spectrum in wadable streams. The protocol consists of three main steps. First, collect quantitative benthic fish and invertebrate samples that can be used to estimate local densities. Second, standardize the fish and invertebrate data by converting all individuals to ataxic units (i.e., individuals identified by size, irrespective of taxonomic identity), and summing individuals within log2 size bins. Third, use linear regression to model the relationship between ataxic M and D estimates. Detailed instructions are provided herein to complete each of these steps, including custom software to facilitate D estimation and size spectra modeling.

This is a protocol to model the size spectrum (scaling relationship between individual mass and population density) for combined fish and invertebrate data from wadable streams and rivers. Methods include: field techniques to collect quantitative fish and invertebrate samples; lab methods to standardize the field data; and statistical data analysis.

מידול ספקטרום הגודל של מאקרוחסרי חוליות ודגים בזרם מערכות אקולוגיות

The size spectrum is an inverse, allometric scaling relationship between average body mass (M) and the density (D) of individuals within an ecological ...

Cortisol Extraction from Sturgeon Fin and Jawbone Matrices

The aims of this study were to develop a technique for the extraction of cortisol from sturgeon fins using two washing solvents (water and isopropanol) and quantify any differences in fin cortisol levels among three main sturgeon species. Fins were harvested from 19 sacrificed sturgeons including seven beluga (Huso huso), seven Siberian (Acipenser baerii), and five sevruga (A. stellatus). The sturgeons were raised in Iranian farms for 2 years (2017-2018), and cortisol extraction analysis was conducted in South Korea (January-February 2019). Jawbones from five H. huso were also used for cortisol extraction. Data were analyzed using the general linear model (GLM) procedure in the SAS environment. The intra- and inter-assay coefficients of variation were 14.15 and 7.70, respectively. Briefly, the cortisol extraction technique involved washing the samples (300 &#177; 10 mg) with 3 mL of solvent (ultrapure water and isopropanol) twice, rotation at 80&#160;rpm for 2.5 min, air-drying the washed samples at room temperature (22-28 &#176;C) for 7 days, further drying the samples using a bead beater at 50 Hz for 32 min and grinding them into powder, applying 1.5 mL methanol to the dried powder (75 &#177; 5 mg), and slow rotation (40 rpm) for 18 h at room temperature with continuous mixing. Following extraction, samples were centrifuged (9,500 x g for 10 min), and 1 mL supernatant was transferred into a new microcentrifuge tube (1.5 mL), incubated at 38 &#176;C to evaporate the methanol, and analyzed via enzyme-linked immunosorbent assay (ELISA). No differences were observed in fin cortisol levels among species or in fin and jawbone cortisol levels between washing solvents. The results of this study demonstrate that the sturgeon jawbone matrix is a promising alternative stress indicator to solid matrices.

In this study, we present a protocol for cortisol extraction from the fin and jawbone of sturgeon species. Fin and jawbone cortisol levels were further examined by comparing two washing solvents followed by ELISA assays. This study piloted the feasibility of jawbone cortisol as a novel stress indicator.

מיצוי הקורטיזול של החדקן פין ואת עצם הלסת מטריצות

The aims of this study were to develop a technique for the extraction of cortisol from sturgeon fins using two washing solvents (water and isopropanol) ...

Extracellular Multi-Unit Recording from the Olfactory Nerve of Teleosts

Recent studies have shown that ocean acidification affects olfactory-driven behavior in fish. This may be due in part to a reduction in olfactory sensitivity in high PCO2/low pH water. To assess the effects of ocean acidification, or olfactory sensitivity in marine fish in general, we propose that extracellular multi-unit recording from the olfactory nerve is the method of choice. Although invasive, it is sensitive, robust, reproducible and independent of external salinity (unlike the electro-olfactogram [EOG], for example). Furthermore, it records a primary sensory input into the CNS, prior to any central processing. We show that this method can show a reduction in olfactory sensitivity that is both temporary and odorant-dependent, using a range of amino acids to construct concentration-response curves and calculate the thresholds of detection.

Extracellular multi-unit recording from the olfactory nerve is a sensitive, robust and reproducible method for assessing olfactory sensitivity in marine fish. It records primary sensory input and is independent of external salinity.

הקלטה רב-יחידה חוץ-תאית מעצב הריח של טאוסט

Recent studies have shown that ocean acidification affects olfactory-driven behavior in fish. This may be due in part to a reduction in olfactory ...

Effectiveness of the Air Stripping in Two Salmonid Fish, Rainbow Trout (Oncorhynchus Mykiss) and Brown Trout (Salmo Trutta Morpha fario)

Egg collection is one of the most crucial procedures during fish reproduction in salmonid hatcheries. Classic methods involve the use of hand massage on fish abdomens to expel the eggs. An alternative method uses the pressure of gas injected into the body cavity, which causes the subsequent release of the eggs. This method is believed to have less negative effects on both the welfare and egg quality of the broodstocks. Herein, we compare the results of air and hand stripping methods with respect to one-year survival and egg quantity and quality in two salmonid fish, rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta morpha fario). Our results indicate that air stripping yielded a better quality of eggs and higher one-year survival rate in rainbow trout. In addition, air stripping resulted in lower mortality rate than the group subjected to hand stripping (25% vs. 35%). The pH and hatching rate of the hand stripped group was lower than those of the air stripped group. In the case of brown trout, the quality of eggs obtained by both hand and air-stripping methods was similar; however, the one-year losses in fish were higher in air stripped group (15% compared to 0% in hand stripped fish). Although the advantages of air stripping method over hand stripping in terms of egg quality might not be observed in all salmonid species, the air-stripping procedure might be a promising option to be adopted in hatcheries as it ensures a high level of reproducibility and efficiency.

Effectiveness of the Air Stripping in Two Salmonid Fish, Rainbow Trout Oncorhynchus Mykiss and Brown Trout Salmo Trutta Morpha fario

The principal aim of this study is to standardize and test the pneumatic method (air stripping) of collecting eggs in rainbow trout and brown trout. This method allows effective and simple collection of the eggs without the necessity of fish abdomen massage.

האפקטיביות של פירוק אוויר בדגים Salmonid שני, פורל הקשת (Oncorhynchus Mykiss) ופורל חום (Salmo Trutta מורפיום fario)

Egg collection is one of the most crucial procedures during fish reproduction in salmonid hatcheries. Classic methods involve the use of hand massage on ...

Developmental Biology

Quantifying Fish Swimming Behavior in Response to Acute Exposure of Aqueous Copper Using Computer Assisted Video and Digital Image Analysis

Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction. However, these responses may be subtle, and measurement can be challenging. Using juvenile white sturgeon (Acipenser transmontanus) with copper exposures, this paper illustrates techniques used for quantifying behavioral responses using computer assisted video and digital image analysis. In previous studies severe impairments in swimming behavior were observed among early life stage white sturgeon during acute and chronic exposures to copper. Sturgeon behavior was rapidly impaired and to the extent that survival in the field would be jeopardized, as fish would be swept downstream, or readily captured by predators. The objectives of this investigation were to illustrate protocols to quantify swimming activity during a series of acute copper exposures to determine time to effect during early lifestage development, and to understand the significance of these responses relative to survival of these vulnerable early lifestage fish. With mortality being on a time continuum, determining when copper first affects swimming ability helps us to understand the implications for population level effects. The techniques used are readily adaptable to experimental designs with other organisms and stressors.

Measuring the impacts of environmental contaminants on fish behavior is often subjective and challenging particularly when dealing with sublethal endpoints. We describe methods including video technology to quantify swimming behavior of early life stage white sturgeon (Acipenser transmontanus) during and after 96 hr acute exposures to various concentrations of copper.

כימות התנהגות שחי דגים בתגובה לחשיפה אקוטית של נחושת מהימית באמצעות וידאו בסיוע מחשב דיגיטלי ניתוח תמונה

Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction.  ...

Neuroscience

Physiological Preparation of Hair Cells from the Sacculus of the American Bullfrog (Rana catesbeiana)

The study of hearing and balance rests upon insights drawn from biophysical studies of model systems. One such model, the sacculus of the American bullfrog, has become a mainstay of auditory and vestibular research. Studies of this organ have revealed how sensory cells hair can actively detect signals from the environment. Because of these studies, we now better understand the mechanical gating and localization of a hair cell&#39;s transduction channels, calcium&#39;s role in mechanical adaptation, and the identity of hair cell currents. This highly accessible organ continues to provide insight into the workings of hair cells. Here we describe the preparation of the bullfrog&#39;s sacculus for biophysical studies on its hair cells. We include the complete dissection procedure and provide specific protocols for the preparation of the sacculus in specific contexts. We additionally include representative results using this preparation, including the calculation of a hair bundle&#39;s instantaneous force-displacement relation and measurement of a bundle&#39;s spontaneous oscillation.

Physiological Preparation of Hair Cells from the Sacculus of the American Bullfrog Rana catesbeiana

The American bullfrog&#39;s (Rana catesbeiana) sacculus permits direct examination of hair-cell physiology. Here the dissection and preparation of the bullfrog&#39;s sacculus for biophysical studies is described. We show representative experiments from these hair cells, including the calculation of a bundle&#39;s force-displacement relation and measurement of its unforced motion.

הכנה פיזיולוגית של תאי שיער מן Sacculus של הבוקסר האמריקאי (<em&gt; רנא catesbeiana</em&gt;)

The study of hearing and balance rests upon insights drawn from biophysical studies of model systems. One such model, the sacculus of the American ...

Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton

The posterior pharyngeal segments of the vertebrate head give rise to the branchial skeleton, the primary site of food processing in fish. The morphology of the fish branchial skeleton is matched to a species' diet. Threespine stickleback fish (Gasterosteus aculeatus) have emerged as a model system to study the genetic and developmental basis of evolved differences in a variety of traits. Marine populations of sticklebacks have repeatedly colonized countless new freshwater lakes and creeks. Adaptation to the new diet in these freshwater environments likely underlies a series of craniofacial changes that have evolved repeatedly in independently derived freshwater populations. These include three major patterning changes to the branchial skeleton: reductions in the number and length of gill raker bones, increases in pharyngeal tooth number, and increased branchial bone lengths. Here we describe a detailed protocol to dissect and flat-mount the internal branchial skeleton in threespine stickleback fish. Dissection of the entire three-dimensional branchial skeleton and mounting it flat into a largely two-dimensional prep allows for the easy visualization and quantification of branchial skeleton morphology. This dissection method is inexpensive, fast, relatively easy, and applicable to a wide variety of fish species. In sticklebacks, this efficient method allows the quantification of skeletal morphology in genetic crosses to map genomic regions controlling craniofacial patterning.

The branchial skeleton, including gill rakers, pharyngeal teeth, and branchial bones, serves as the primary site of food processing in most fish. Here we describe a protocol to dissect and flat-mount this internal skeleton in threespine sticklebacks. This method is also applicable to a variety of other fish species.

Dissection ו-הרכבה שטוחה של שלד Threespine קוצן branchial

The posterior pharyngeal segments of the vertebrate head give rise to the branchial skeleton, the primary site of food processing in fish. The morphology ...

Biology

Gonadectomy and Blood Sampling Procedures in the Small Size Teleost Model Japanese Medaka (Oryzias latipes)

Sex steroids, produced by the gonads, play an essential role in brain and pituitary tissue plasticity and in the neuroendocrine control of reproduction in all vertebrates by providing feedback to the brain and pituitary. Teleost fishes possess a higher degree of tissue plasticity and variation in reproductive&#160;strategies compared to mammals and appear to be useful models to investigate the role of sex steroids and the mechanisms by which they act. The removal of the main source of sex steroid production using gonadectomy together with blood sampling to measure steroid levels has been well-established and fairly feasible in bigger fish and is a powerful technique to investigate the role and effects of sex steroids. However, these techniques raise challenges when implemented in small size teleost models. Here, we describe the step-by-step procedures of gonadectomy in both males and female Japanese medaka followed by blood sampling. These protocols are shown to be highly feasible in medaka indicated by a high survival rate, safety for the life span and phenotype of the fish, and reproducibility in terms of sex steroid clearance. The use of these procedures combined with the other advantages of using this small teleost model will greatly improve the understanding of feedback mechanisms in the neuroendocrine control of reproduction and tissue plasticity provided by sex steroids in vertebrates.

Gonadectomy and Blood Sampling Procedures in the Small Size Teleost Model Japanese Medaka Oryzias latipes

The article describes a quick protocol to gonadectomize and sample blood from the small teleost fish, using Japanese medaka (Oryzias latipes) as a model, to investigate the role of sex steroids in animal physiology.

הליכי גונדקטומיה ודגימה בדם במודל טלוסט קטן מדאקה(Oryzias latipes)

Sex steroids, produced by the gonads, play an essential role in brain and pituitary tissue plasticity and in the neuroendocrine control of reproduction in ...