Pub Date : 1997-10-01DOI: 10.1577/1548-8640(1997)059<0280:OMEFYP>2.3.CO;2
Eric G. Unkenholz, Michael L. Brown, K. Pope
Differentiating between hatchery and naturally reproduced fishes is difficult because of the lack of appropriate marking techniques. Chemical immersion techniques can be a practical method for mass marking juvenile fishes. The objectives of this study were to determine the concentration of oxytetracycli ne (OTC) hydrochloride needed to effectively mark age-0 yellow perch Perca flavescens. to observe the retention lime of the mark, and to measure the persistence of OTC in body tissues. Fish were immersed in 309, 534, and 748 mg OTC/L for 12 h. Initial fish collections were made weekly, and monthly collections began 1 month postmarking for tissue and mark analyses. High-pressure liquid chromatography was used to quantitate OTC residues in tissues; OTC concentrations were undetectable (<0.05 jxg/g) in the edible tissue (muscle) at 110 d postimmersion. Aided by a Nikon Labophot fluorescence microscope, we discerned otolith marks 56 d postimmersion on 100% of the fish treated at 534 and 748 mg/L. Marks were still visible on 100% of the fish treated with 534 and 748 mg/L at 8 months postimmersion.
{"title":"Oxytetracycline Marking Efficacy for Yellow Perch Fingerlings and Temporal Assays of Tissue Residues","authors":"Eric G. Unkenholz, Michael L. Brown, K. Pope","doi":"10.1577/1548-8640(1997)059<0280:OMEFYP>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0280:OMEFYP>2.3.CO;2","url":null,"abstract":"Differentiating between hatchery and naturally reproduced fishes is difficult because of the lack of appropriate marking techniques. Chemical immersion techniques can be a practical method for mass marking juvenile fishes. The objectives of this study were to determine the concentration of oxytetracycli ne (OTC) hydrochloride needed to effectively mark age-0 yellow perch Perca flavescens. to observe the retention lime of the mark, and to measure the persistence of OTC in body tissues. Fish were immersed in 309, 534, and 748 mg OTC/L for 12 h. Initial fish collections were made weekly, and monthly collections began 1 month postmarking for tissue and mark analyses. High-pressure liquid chromatography was used to quantitate OTC residues in tissues; OTC concentrations were undetectable (<0.05 jxg/g) in the edible tissue (muscle) at 110 d postimmersion. Aided by a Nikon Labophot fluorescence microscope, we discerned otolith marks 56 d postimmersion on 100% of the fish treated at 534 and 748 mg/L. Marks were still visible on 100% of the fish treated with 534 and 748 mg/L at 8 months postimmersion.","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"54 1","pages":"280-284"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88251740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-01DOI: 10.1577/1548-8640(1997)059<0297:OOSSOS>2.3.CO;2
C. Mischke, Joseph E. Morris
Abstract Although propagation of sunfish Lepomis spp. has historically been done in earthen ponds, there is interest in producing these fish in the laboratory. The objective of this study was to spawn sunfish out of season by means of temperature and photoperiod manipulation. By manipulating temperature and photoperiod, we were able to spawn bluegills L. machrochirus over a 6-month period (December 1994–May 1995): 41 spawns. averaging 20.000 larvae each, were obtained from 24 females. By manipulation of photoperiod alone, we were able to spawn fish during a 3-month period (October–December 1995): 21 bluegill spawns of about 20.000 larvae each and 7 spawns of hybrid sunfish (female green sunfish L. cyanellus × male bluegills) of about 10,000 larvae each were obtained from 12 female bluegills and 24 female green sunfish, respectively. This protocol allows for production of sunfish larvae, regardless of season and without the use of hormones, for both laboratory studies and aquaculture stocking.
{"title":"OUT-OF-SEASON SPAWNING OF SUNFISH LEPOMIS SPP. IN THE LABORATORY","authors":"C. Mischke, Joseph E. Morris","doi":"10.1577/1548-8640(1997)059<0297:OOSSOS>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0297:OOSSOS>2.3.CO;2","url":null,"abstract":"Abstract Although propagation of sunfish Lepomis spp. has historically been done in earthen ponds, there is interest in producing these fish in the laboratory. The objective of this study was to spawn sunfish out of season by means of temperature and photoperiod manipulation. By manipulating temperature and photoperiod, we were able to spawn bluegills L. machrochirus over a 6-month period (December 1994–May 1995): 41 spawns. averaging 20.000 larvae each, were obtained from 24 females. By manipulation of photoperiod alone, we were able to spawn fish during a 3-month period (October–December 1995): 21 bluegill spawns of about 20.000 larvae each and 7 spawns of hybrid sunfish (female green sunfish L. cyanellus × male bluegills) of about 10,000 larvae each were obtained from 12 female bluegills and 24 female green sunfish, respectively. This protocol allows for production of sunfish larvae, regardless of season and without the use of hormones, for both laboratory studies and aquaculture stocking.","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"64 1","pages":"297-302"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80893759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-01DOI: 10.1577/1548-8640(1997)059<0307:TNATTM>2.3.CO;2
G. M. Matthews, N. Paasch, S. Achord, K. Mcintyre, J. R. Harmon
Abstract A system that allows anesthetization of juvenile salmonids before netting during a handling and marking operation is described. Our purpose for designing the system was to reduce or minimize any debilitating effects associated with these activities. When compared with smolts handled and marked in the traditional manner, use of the technique resulted in a significant reduction in the mortality of naturally migrating smolts of spring-summer chinook salmon Oncorhynchus tshawytscha during a posthandling and marking seawater challenge performance test. The treatment resulted in lower, but not significantly lower, plasma cortisol levels; however, sample sizes may have been too small for statistical verification. With a little ingenuity, the technique should be adaptable to most smolt handling or marking operations.
{"title":"Technical Notes: A Technique to Minimize the Adverse Effects Associated with Handling and Marking Salmonid Smolts","authors":"G. M. Matthews, N. Paasch, S. Achord, K. Mcintyre, J. R. Harmon","doi":"10.1577/1548-8640(1997)059<0307:TNATTM>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0307:TNATTM>2.3.CO;2","url":null,"abstract":"Abstract A system that allows anesthetization of juvenile salmonids before netting during a handling and marking operation is described. Our purpose for designing the system was to reduce or minimize any debilitating effects associated with these activities. When compared with smolts handled and marked in the traditional manner, use of the technique resulted in a significant reduction in the mortality of naturally migrating smolts of spring-summer chinook salmon Oncorhynchus tshawytscha during a posthandling and marking seawater challenge performance test. The treatment resulted in lower, but not significantly lower, plasma cortisol levels; however, sample sizes may have been too small for statistical verification. With a little ingenuity, the technique should be adaptable to most smolt handling or marking operations.","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"25 1","pages":"307-309"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82014643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-01DOI: 10.1577/1548-8640(1997)059<0285:AOLEFC>2.3.CO;2
M. Hayes, R. W. Carmichael, M. Keefe, T. A. Whitesel
Abstract We used three sampling methods to estimate mean fork lengths and variances for chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss that were reared in compartmented and standard raceways. Size segregation of fish in compartmented raceways was also evaluated. Accurate estimates of mean fork length from raceway populations of chinook salmon and steelhead were difficult to obtain. In both compartmented and standard raceways, our sampling methods tended to underestimate the mean. For compartmented raceways, the most accurate estimates of mean fork length were obtained by pooling samples collected from each compartment. In standard raceways, the most accurate estimates of mean fork length were obtained when one net sample was taken after fish were crowded in the raceway. We also found that accurate estimates of fork length variance were difficult to obtain. No sampling method produced accurate estimates more than 67% of the time; therefore, no sampling method was recommended for estimating...
摘要采用三种抽样方法，对在分隔和标准跑道中饲养的奇努克鲑鱼Oncorhynchus tshawytscha和steelhead O. mykiss的平均叉长和方差进行了估计。还评估了分隔沟道中鱼类的大小分离。从切努克鲑鱼和钢头鱼的跑道种群中准确估计平均叉长是困难的。在分隔和标准轨道中，我们的抽样方法都倾向于低估平均值。对于分隔的跑道，最准确的平均叉长估计是通过汇集从每个隔间收集的样本获得的。在标准沟道中，最准确的平均叉长估计是在鱼在沟道中拥挤后取一个网样本时获得的。我们还发现叉子长度方差的准确估计是难以获得的。没有一种抽样方法能在67%以上的时间内产生准确的估计;因此，不建议采用抽样方法来估计……
{"title":"Accuracy of Length Estimates for Chinook Salmon and Steelhead in Compartmented and Standard Hatchery Raceways","authors":"M. Hayes, R. W. Carmichael, M. Keefe, T. A. Whitesel","doi":"10.1577/1548-8640(1997)059<0285:AOLEFC>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0285:AOLEFC>2.3.CO;2","url":null,"abstract":"Abstract We used three sampling methods to estimate mean fork lengths and variances for chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss that were reared in compartmented and standard raceways. Size segregation of fish in compartmented raceways was also evaluated. Accurate estimates of mean fork length from raceway populations of chinook salmon and steelhead were difficult to obtain. In both compartmented and standard raceways, our sampling methods tended to underestimate the mean. For compartmented raceways, the most accurate estimates of mean fork length were obtained by pooling samples collected from each compartment. In standard raceways, the most accurate estimates of mean fork length were obtained when one net sample was taken after fish were crowded in the raceway. We also found that accurate estimates of fork length variance were difficult to obtain. No sampling method produced accurate estimates more than 67% of the time; therefore, no sampling method was recommended for estimating...","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"28 1","pages":"285-292"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84169014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-01DOI: 10.1577/1548-8640(1997)059<0272:APORTS>2.3.CO;2
F. Lahnsteiner, T. Weismann, R. Patzner
Abstract Changes in fertility, motility, sperm metabolism, and seminal plasma composition during 2-h in vitro storage on ice (2 mL semen in a 10-mL centrifuge tube with a diameter of 1 cm) were investigated for semen from rainbow trout Oncorhynchus mykiss. After 2 h, the fertilization capacity was reduced by about 35%, motility rate by 65%, and swimming velocity by 26% in comparison with freshly collected semen. The seminal fluid osmolality and sodium and potassium concentrations decreased, while the spermatozoan sodium and potassium levels increased, indicating ion influx into the cells. The increase in glycerol, fatty acid, and triglyceride levels of the seminal fluid and of the spermatozoa indicated aging of semen. Spermatozoan adenylate kinase, malate dehydrogenase, and respiratory activities, and thus energy requirements of semen, were high after 2-h semen storage compared with fresh semen. Spermatozoa used glucose for energy supply as its levels decreased. Adenosine triphosphate, NADH, and lactate l...
{"title":"Aging Processes of Rainbow Trout Semen during Storage","authors":"F. Lahnsteiner, T. Weismann, R. Patzner","doi":"10.1577/1548-8640(1997)059<0272:APORTS>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0272:APORTS>2.3.CO;2","url":null,"abstract":"Abstract Changes in fertility, motility, sperm metabolism, and seminal plasma composition during 2-h in vitro storage on ice (2 mL semen in a 10-mL centrifuge tube with a diameter of 1 cm) were investigated for semen from rainbow trout Oncorhynchus mykiss. After 2 h, the fertilization capacity was reduced by about 35%, motility rate by 65%, and swimming velocity by 26% in comparison with freshly collected semen. The seminal fluid osmolality and sodium and potassium concentrations decreased, while the spermatozoan sodium and potassium levels increased, indicating ion influx into the cells. The increase in glycerol, fatty acid, and triglyceride levels of the seminal fluid and of the spermatozoa indicated aging of semen. Spermatozoan adenylate kinase, malate dehydrogenase, and respiratory activities, and thus energy requirements of semen, were high after 2-h semen storage compared with fresh semen. Spermatozoa used glucose for energy supply as its levels decreased. Adenosine triphosphate, NADH, and lactate l...","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"242 1","pages":"272-279"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76979471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-01DOI: 10.1577/1548-8640(1997)059<0303:UOFDIO>2.3.CO;2
M. E. Barnes, Rick J. Cordes, W. A. Sayler
Abstract The influence of daily formalin treatments on eyed egg and fry mortality was evaluated during the incubation of eyed eggs of inland fall chinook salmon Oncorhynchus tshawytscha. A 3–5% increase in survival was observed in trays of eggs treated with formalin at 1,667 mg/L for 15 min daily from egg eye-up until just before hatch compared with incubation trays from which dead eggs were manually removed to control Saprolegnia. Egg survival in trays receiving both daily formalin treatments and manual egg removal did not differ significantly from those trays receiving only formalin treatments. Significant reductions in mortality were observed prehatch when formalin was used, and there was no difference in mortality from hatch to fry swim-up. Both formalin treatments and the hand-picking of dead eggs adequately controlled visible fungal development from egg eye-up to hatching.
{"title":"Use of Formalin during Incubation of Eyed Eggs of Inland Fall Chinook Salmon","authors":"M. E. Barnes, Rick J. Cordes, W. A. Sayler","doi":"10.1577/1548-8640(1997)059<0303:UOFDIO>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0303:UOFDIO>2.3.CO;2","url":null,"abstract":"Abstract The influence of daily formalin treatments on eyed egg and fry mortality was evaluated during the incubation of eyed eggs of inland fall chinook salmon Oncorhynchus tshawytscha. A 3–5% increase in survival was observed in trays of eggs treated with formalin at 1,667 mg/L for 15 min daily from egg eye-up until just before hatch compared with incubation trays from which dead eggs were manually removed to control Saprolegnia. Egg survival in trays receiving both daily formalin treatments and manual egg removal did not differ significantly from those trays receiving only formalin treatments. Significant reductions in mortality were observed prehatch when formalin was used, and there was no difference in mortality from hatch to fry swim-up. Both formalin treatments and the hand-picking of dead eggs adequately controlled visible fungal development from egg eye-up to hatching.","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"94 1","pages":"303-306"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83564560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-01DOI: 10.1577/1548-8640(1997)059<0218:CGSFMW>2.3.CO;2
K. Koupal, J. Satterfield, S. Flickinger
Abstract Spawn-taking efforts for walleyes Stizostedion vitreum in Colorado were used to evaluate gear selectivity in terms of catch per unit effort (CPUE) and sex ratio. Seasonal electrofishing CPUE ranged from 28 to 197 walleyes/h, whereas gillnetting CPUE ranged between 0.5 and 3.0 walleyes/net-night. Corresponding sex ratios (male: female) for these gears ranged between 9.5 and 48.3 for electrofishing and 0.3 and 0.5 for gillnetting. Weighted percent hatching success was also determined for eggs fertilized with milt from electrofished males versus gillnetted males to determine if electrofishing harmed male gametes. The weighted percent hatch for electrofishing was 69.1%, compared with 76.9% for gillnetting (P = 0.357). These results suggest that electrofishing may be used to enhance numbers of male broodstock during spawn-taking operations. Electrofishing is an efficient means of capturing male broodstock during spawning season, and the resultant hatching percentage of eggs fertilized with these males...
{"title":"Comparative Gear Selectivity for Male Walleyes and Influence of Method of Capture on Resultant Hatching Success","authors":"K. Koupal, J. Satterfield, S. Flickinger","doi":"10.1577/1548-8640(1997)059<0218:CGSFMW>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0218:CGSFMW>2.3.CO;2","url":null,"abstract":"Abstract Spawn-taking efforts for walleyes Stizostedion vitreum in Colorado were used to evaluate gear selectivity in terms of catch per unit effort (CPUE) and sex ratio. Seasonal electrofishing CPUE ranged from 28 to 197 walleyes/h, whereas gillnetting CPUE ranged between 0.5 and 3.0 walleyes/net-night. Corresponding sex ratios (male: female) for these gears ranged between 9.5 and 48.3 for electrofishing and 0.3 and 0.5 for gillnetting. Weighted percent hatching success was also determined for eggs fertilized with milt from electrofished males versus gillnetted males to determine if electrofishing harmed male gametes. The weighted percent hatch for electrofishing was 69.1%, compared with 76.9% for gillnetting (P = 0.357). These results suggest that electrofishing may be used to enhance numbers of male broodstock during spawn-taking operations. Electrofishing is an efficient means of capturing male broodstock during spawning season, and the resultant hatching percentage of eggs fertilized with these males...","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"29 1","pages":"218-221"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88262728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-01DOI: 10.1577/1548-8640(1997)059<0235:LCCAIA>2.3.CO;2
Mark C. Bates, T. Tiersch
Abstract An image analysis system based on the Macintosh personal computer and public domain software (NIH Image, version 1.57) allows capture of digitized images for data analysis. Three techniques for image capture and aquisition of linear and area measurements from digitized images were tested: (1) estimation of egg size, (2) estimation of number of eggs or fry, and (3) measurement of fish length. For estimation of egg size, egg samples were taken by catheterization from two female channel catfish Ictalurus punclatus. Egg diameters measured manually (1,82 ± 0.27 and 2.59 ± 0.19 mm) were not significantly different (P = 0.08 and 0.20) from the diameters estimated with image analysis (1.92 ± 0.21 and 2.63 ± 0.17 mm). For egg counting, channel catfish eggs were hand-stripped into Hanks' balanced salt solution and divided into seven 15-mL aliquots. The number of eggs was determined manually and images were captured for analysis. The number of eggs determined manually (436 ± 41) was not significantly differ...
基于Macintosh个人计算机和公共领域软件(NIH image, version 1.57)的图像分析系统允许捕获数字化图像进行数据分析。测试了三种图像捕获和获取数字化图像的线性和面积测量技术:(1)估计卵的大小，(2)估计卵或苗的数量，(3)测量鱼的长度。为了估计卵的大小，卵的样本是通过导管取卵，从两个雌性通道鲶鱼伊卡塔鲁斯punclatus。人工测得的鸡蛋直径分别为1.82±0.27和2.59±0.19 mm，与图像分析测得的鸡蛋直径分别为1.92±0.21和2.63±0.17 mm，差异无统计学意义(P = 0.08和0.20)。为了计数，鲶鱼卵被手工剥离到汉克斯的平衡盐溶液中，分成7份15毫升的等分。卵子的数量是人工确定的，并捕获图像进行分析。人工检卵数(436±41)与人工检卵数无显著差异。
{"title":"Low-Cost Computer-Assisted Image Analysis for Fisheries Research","authors":"Mark C. Bates, T. Tiersch","doi":"10.1577/1548-8640(1997)059<0235:LCCAIA>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0235:LCCAIA>2.3.CO;2","url":null,"abstract":"Abstract An image analysis system based on the Macintosh personal computer and public domain software (NIH Image, version 1.57) allows capture of digitized images for data analysis. Three techniques for image capture and aquisition of linear and area measurements from digitized images were tested: (1) estimation of egg size, (2) estimation of number of eggs or fry, and (3) measurement of fish length. For estimation of egg size, egg samples were taken by catheterization from two female channel catfish Ictalurus punclatus. Egg diameters measured manually (1,82 ± 0.27 and 2.59 ± 0.19 mm) were not significantly different (P = 0.08 and 0.20) from the diameters estimated with image analysis (1.92 ± 0.21 and 2.63 ± 0.17 mm). For egg counting, channel catfish eggs were hand-stripped into Hanks' balanced salt solution and divided into seven 15-mL aliquots. The number of eggs was determined manually and images were captured for analysis. The number of eggs determined manually (436 ± 41) was not significantly differ...","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"36 1","pages":"235-240"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91303804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-01DOI: 10.1577/1548-8640(1997)059<0241:GMAMRO>2.3.CO;2
Adam Zerrenner, D. Josephson, C. Krueger
Abstract Growth, mortality, mark retention, and mark readability were compared among control and treatment groups of 197–265-mm hatchery brook trout Salvelinus fonitinalis marked with visible implant (VI) tags, adipose tin (AD) clips, or stainless steel circularstrap jaw tags. Based on growth rates calculated for individual fish after 90 d, brook trout marked with VI tags grew faster than those with jaw tags (P G 0.03). Mortality was higher after 251 d for jaw-tagged fish (45%) than the cumulative mortality (8.3%) observed among VI-tagged, AD clipped, and control fish, Mark retention was 759c for VI tags, 99% for jaw tags, and 100% for AD clips, Visible implant tag loss was greatest within 7 d after insertion. After 251 d. 37% of the VI tags were unreadable. but 92% of the “unreadable” tags were readable if magnification and light were used. Unreadability could limit the usefulness of VI tags in multiyear studies unless problem tags can be removed from the fish to read tag codes.
{"title":"Growth, Mortality, and Mark Retention of Hatchery Brook Trout Marked with Visible Implant Tags, Jaw Tags, and Adipose Fin Clips","authors":"Adam Zerrenner, D. Josephson, C. Krueger","doi":"10.1577/1548-8640(1997)059<0241:GMAMRO>2.3.CO;2","DOIUrl":"https://doi.org/10.1577/1548-8640(1997)059<0241:GMAMRO>2.3.CO;2","url":null,"abstract":"Abstract Growth, mortality, mark retention, and mark readability were compared among control and treatment groups of 197–265-mm hatchery brook trout Salvelinus fonitinalis marked with visible implant (VI) tags, adipose tin (AD) clips, or stainless steel circularstrap jaw tags. Based on growth rates calculated for individual fish after 90 d, brook trout marked with VI tags grew faster than those with jaw tags (P G 0.03). Mortality was higher after 251 d for jaw-tagged fish (45%) than the cumulative mortality (8.3%) observed among VI-tagged, AD clipped, and control fish, Mark retention was 759c for VI tags, 99% for jaw tags, and 100% for AD clips, Visible implant tag loss was greatest within 7 d after insertion. After 251 d. 37% of the VI tags were unreadable. but 92% of the “unreadable” tags were readable if magnification and light were used. Unreadability could limit the usefulness of VI tags in multiyear studies unless problem tags can be removed from the fish to read tag codes.","PeriodicalId":22850,"journal":{"name":"The Progressive Fish-culturist","volume":"12 1","pages":"241-245"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75548129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-01DOI: 10.1577/1548-8640(1497)059<0246:TNAOBO>2.3.CO;2
C. True, Anthony Loera, Norberto Castro Castro
Abstract Totoaba Totoaba macdonaldi is the largest member in the family Sciaenidae and is considered endangered. Broodstock were collected at depths of 20–50 m in the northern Sea of Cortez, and fish suffered from severe decompression problems when brought to the surface. A field decompression technique was developed to alleviate these problems. Pertinent field handling and prophylactic measures were applied to successfully transport and acclimate the broodfish to the facilities at the Faculty of Marine Science in Ensenada, Mexico. Totoaba adapted to an enclosed environment within 30–40 d after capture. Ten broodfish, constituting the largest captive Totoaba population, are awaiting the appropriate conditions for gonad maturation and spawning.
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