Size and Weight Relationships for the Golden Crab, Chaceon fenneri, and the Red Crab, Chaceon quinquedens, from the Eastern Gulf of Mexico

Carapace length, carapace width, and weight relationships are discussed for the golden crab, Chaceon fenneri, and the red crab, Chaceon quinquedens, from the eastern Gulf of Mexico. Males of both species were significantly larger than females in comparisons of means of all measured parameters. Relationships between carapace length and carapace width, carapace length and weight, and carapace width and weight were similar between Atlantic and Gulf of Mexico populations for both species

Size and Weight Relationships for the Golden Crab, Chaceon fenneri, and the Red Crab, Chaceon quinquedens, from the Eastern Gulf of Mexico

Carapace length, carapace width, and weight relationships are discussed for the golden crab, Chaceon fenneri, and the red crab, Chaceon quinquedens, from the eastern Gulf of Mexico. Males of both species were significantly larger than females in comparisons of means of all measured parameters. Relationships between carapace length and carapace width, carapace length and weight, and carapace width and weight were similar between Atlantic and Gulf of Mexico populations for both species

Biochemical Composition of Embryonic Blue Crabs \u3ci\u3eCallinectes sapidus\u3c/i\u3e Rathbun 1896 (Crustacea : Decapoda) from the Gulf of Mexico

Blue crab Callinectes sapidus embryos from the Mississippi Sound were sampled in spring and in late summer to determine patterns of biochemical composition and of yolk utilization during embryogenesis and to ascertain potential seasonal differences in biochemical composition. The diameter of spring embryos was similar to 6% greater than summer embryos but this significant size difference was due to increased water content, not to increased organic content. The general trend in initial biochemical composition was similar in both seasons; protein was the primary component at similar to 50% of initial dry weight followed by lipid (similar to 30%), ash (similar to 8%) and carbohydrate (6%). The general trend for utilization of organic reserves during embryogenesis was also similar seasonally. Lipid was the primary component metabolized during embryogenesis (44-48% of initial stores were utilized) followed by protein (13-16% utilized) and carbohydrate (similar to 13% utilized). Calculated on a dry weight basis, spring embryos had significantly lower lipid but significantly higher ash than summer embryos; there were no significant seasonal differences in protein or carbohydrate. Caloric expenditure on a dry weight basis was significantly different seasonally. There appear to be geographic differences among blue crabs; our results differ from those of a previous study of blue crab embryos from North Carolina waters

Estimates of Harvest Potential and Distribution of the Deep Sea Red Crab, Chaceon quinquedens, in the North Central Gulf of Mexico

Harvest potential, relative abundance, and geographic and bathymetric distribution are discussed for the red crab, Chaceon quinquedens, in the northcentral Gulf of Mexico. Harvest potential is expressed as the number of trapable crabs present on fishing grounds defined as depths ranging from 677 m to 1043 m between 87.5o and 88.5oW longitude. Using various estimates of the effective fishing area (EFA) of a trap, the number of trapable red crabs on the fishing grounds ranged from 3.7 x 106 to 10.7 x 106. Estimatesofcrabnumberssuggest there is a potential for commercial harvest in the northcentral Gulf of Mexico, east of the Mississippi River. However, fishery development must take into consideration the preponderance of females on the defined fishing grounds (MF ratio = 1:2.1) and the high incidence of ovigerous females (~20%) during much of the year. Females generally dominated at all depth strata, but the proportion of males to females increased with depth. Reduced numbers of red crabs were collected off the western Louisiana coast and a shift in depth distribution was found. Minimum upper depth limit for red crabs west of the Mississippi River was 860 m as compared to 677 m east of the River. The known range of C. fenneri is extended to 92o12 W longitude

Estimates of Harvest Potential and Distribution of the Deep Sea Red Crab, Chaceon quinquedens, in the North Central Gulf of Mexico

Harvest potential, relative abundance, and geographic and bathymetric distribution are discussed for the red crab, Chaceon quinquedens, in the northcentral Gulf of Mexico. Harvest potential is expressed as the number of trapable crabs present on fishing grounds defined as depths ranging from 677 m to 1043 m between 87.5o and 88.5oW longitude. Using various estimates of the effective fishing area (EFA) of a trap, the number of trapable red crabs on the fishing grounds ranged from 3.7 x 106 to 10.7 x 106. Estimatesofcrabnumberssuggest there is a potential for commercial harvest in the northcentral Gulf of Mexico, east of the Mississippi River. However, fishery development must take into consideration the preponderance of females on the defined fishing grounds (MF ratio = 1:2.1) and the high incidence of ovigerous females (~20%) during much of the year. Females generally dominated at all depth strata, but the proportion of males to females increased with depth. Reduced numbers of red crabs were collected off the western Louisiana coast and a shift in depth distribution was found. Minimum upper depth limit for red crabs west of the Mississippi River was 860 m as compared to 677 m east of the River. The known range of C. fenneri is extended to 92o12 W longitude

Blue Crab Larval Dispersion and Retention in the Mississippi Bight: Testing the Hypothesis

An hypothesis relating physical forcing to dispersion and retention of blue crab larvae was tested in the area of the Mississippi Bight. Seasonal circulation patterns derived from a 3-dimensional, primitive equation, sigma-coordinate model of the Gulf of Mexico (GOM) indicate favorable conditions for offshore dispersal of larvae and their return to nearshore waters as megalopae occur between April and October. Large basin-scale events, such as Loop Current intrusions into the GOM with spin-off eddy generation and anomalies in average wind stress may interrupt this circulation pattern and change the settlement success rate. Meteorological and hydrological factors thought to influence settlement were compared to daily records of megalopal abundance in Mississippi Sound for the years 1991 through 1999. Wind stress was strongly correlated with settlement success. Eastward wind stress during the months of July and August, when the larvae are at sea, and westward wind stress during recruitment in September and October were important in retaining larvae in the general area and subsequently returning them near shore as megalopae, respectively. Northward intrusion of the Loop Current and warm core ring detachment during late summer altered circulation patterns and decreased settlement success

Morphometry of Juvenile and Subadult \u3ci\u3eLoligo pealei\u3c/i\u3e and \u3ci\u3eL. plei\u3c/i\u3e from the Northern Gulf of Mexico

Two species of Loligo are abundant in northern Gulf waters: the long-finned squid, Loligo pealei. and the arrow squid, Loligo plei. Variability within species and similarities between the species often hamper accurate identification. The two species more closely resemble each other in areas of sympatry. and there is overlap in almost all of the diagnostic characters. Small specimens of Loligo are not easily identified. and there are few studies detailing their morphometry. Because of the taxonomic uncertainties associated with the identification of juveniles and subadults of L. pealei and L. plei, the species were differentiated by isoelectric focusing. and morphometric characters and indices of potential use in species separation were evaluated. Emphasis was placed on those taxonomic characters suitable for use in the field. Best discrimination between the two species was achieved with combinations of measurements of characters and calculated indices associated with cartilaginous structures (funnel cartilage length, gladius width [GW1, nuchal cartilage length, and rachis width [RW]) and the shape of the gladius. An arbitrary cutoff in GWIRW ratio of 2.7 (ratio of the greatest width of the gladius to the width of the free rachis at the junction of the vane) correctly classified 100% of the L. plei and 91% of the L. pealei. The overall shape of the gladius (broader and more rounded in L. pealei), presence or absence of marginal ribs in the vane of the gladius, and the nature of the junction of the vane and free rachis (junction gradual and not distinct in L. peale;) were also useful in distinguishing the two species

The effects of ship noise on marine mammals - a review

viii, 174 hlm, 23 c

Assessing reproducibility of inherited variants detected with short-read whole genome sequencing

Background: Reproducible detection of inherited variants with whole genome sequencing (WGS) is vital for the implementation of precision medicine and is a complicated process in which each step affects variant call quality. Systematically assessing reproducibility of inherited variants with WGS and impact of each step in the process is needed for understanding and improving quality of inherited variants from WGS. Results: To dissect the impact of factors involved in detection of inherited variants with WGS, we sequence triplicates of eight DNA samples representing two populations on three short-read sequencing platforms using three library kits in six labs and call variants with 56 combinations of aligners and callers. We find that bioinformatics pipelines (callers and aligners) have a larger impact on variant reproducibility than WGS platform or library preparation. Single-nucleotide variants (SNVs), particularly outside difficult-to-map regions, are more reproducible than small insertions and deletions (indels), which are least reproducible when > 5 bp. Increasing sequencing coverage improves indel reproducibility but has limited impact on SNVs above 30x. Conclusions: Our findings highlight sources of variability in variant detection and the need for improvement of bioinformatics pipelines in the era of precision medicine with WGS.Peer reviewe

Assessing Reproducibility of Inherited Variants Detected With Short-Read Whole Genome Sequencing

Background: Reproducible detection of inherited variants with whole genome sequencing (WGS) is vital for the implementation of precision medicine and is a complicated process in which each step affects variant call quality. Systematically assessing reproducibility of inherited variants with WGS and impact of each step in the process is needed for understanding and improving quality of inherited variants from WGS. Results: To dissect the impact of factors involved in detection of inherited variants with WGS, we sequence triplicates of eight DNA samples representing two populations on three short-read sequencing platforms using three library kits in six labs and call variants with 56 combinations of aligners and callers. We find that bioinformatics pipelines (callers and aligners) have a larger impact on variant reproducibility than WGS platform or library preparation. Single-nucleotide variants (SNVs), particularly outside difficult-to-map regions, are more reproducible than small insertions and deletions (indels), which are least reproducible when \u3e 5 bp. Increasing sequencing coverage improves indel reproducibility but has limited impact on SNVs above 30×. Conclusions: Our findings highlight sources of variability in variant detection and the need for improvement of bioinformatics pipelines in the era of precision medicine with WGS