Hyperactivity, blood lactic acid and mortality in channel catfish

Mortality in submature channel catfish, Ictalurus punctatus (Rafinesque), caught in the Mississippi River and stocked in Iowa streams and ponds, led to this investigation in 1961-1963. The major findings can be summarized as follows: The mean concentration of lactic acid in the blood of unexercised channel catfish varied from 2.3 to 7.6 mg/100 ml of whole blood. That of fish subjected individually to forced exercise varied from 21.1 to 44.1 mg/100 ml after 5 minutes of exercise and from 59.1 to 67.6 mg/100 ml after 15 minutes of exercise. A lower concentration of lactic acid, 28.2 mg/100 ml, for fish exercised 15 minutes in a group indicates that fish exercised in a group were not subjected to as strenuous muscular activity as were those exercised individually. Mean lactic acid values were usually greater at higher temperatures, both for unexercised and exercised fish

Simulation of Tail Weight Distributions in Biological Year 1986–2006 Landings of Brown Shrimp, Farfantepenaeus aztecus, from the Northern Gulf of Mexico Fishery

Size distribution within re- ported landings is an important aspect of northern Gulf of Mexico penaeid shrimp stock assessments. It reflects shrimp population characteristics such as numerical abundance of various sizes, age structure, and vital rates (e.g. recruitment, growth, and mortality), as well as effects of fishing, fishing power, fishing practices, sampling, size-grading, etc. The usual measure of shrimp size in archived landings data is count (C) the number of shrimp tails (abdomen or edible portion) per pound (0.4536 kg). Shrimp are marketed and landings reported in pounds within tail count categories. Statistically, these count categories are count class intervals or bins with upper and lower limits expressed in C. Count categories vary in width, overlap, and frequency of occurrence within the landings. The upper and lower limits of most count class intervals can be transformed to lower and upper limits (respectively) of class intervals expressed in pounds per shrimp tail, w, the reciprocal of C (i.e. w = 1/C). Age based stock assessments have relied on various algorithms to estimate numbers of shrimp from pounds landed within count categories. These algorithms required un- derlying explicit or implicit assumptions about the distribution of C or w. However, no attempts were made to assess the actual distribution of C or w. Therefore, validity of the algorithms and assumptions could not be determined. When different algorithms were applied to landings within the same size categories, they produced different estimates of numbers of shrimp. This paper demonstrates a method of simulating the distribution of w in reported biological year landings of shrimp. We used, as examples, landings of brown shrimp, Farfantepenaeus aztecus, from the northern Gulf of Mexico fishery in biological years 1986–2006. Brown shrimp biological year, Ti, is defined as beginning on 1 May of the same calendar year as Ti and ending on 30 April of the next calendar year, where subscript i is the place marker for biological year. Biological year landings encompass most if not all of the brown shrimp life cycle and life span. Simulated distributions of w reflect all factors influencing sizes of brown shrimp in the landings within a given biological year. Our method does not require a priori assumptions about the parent distributions of w or C, and it takes into account the variability in width, overlap, and frequency of occurrence of count categories within the landings. Simulated biological year distributions of w can be transformed to equivalent distributions of C. Our method may be useful in future testing of previously applied algorithms and development of new estimators based on statistical estimation theory and the underlying distribution of w or C. We also examine some applications of biological year distributions of w, and additional variables derived from them

Trends in Ex-Vessel Value and Size Composition of Reported Annual Catches of Pink Shrimp from the Tortugas Fishery, 1960-1978

Exponential models were used to characterize (1) ex-vessel value (in dollars) per shrimp by size category (count; i.e., number of shrimp per pound, heads off), (2) size composition (expressed as cumulative weight of the catch in pounds, heads off, by size category), and (3) ex-vessel value composition (expressed as cumulative ex-vessel value, in dollars, of the catch by size category) for reported annual catches (inshore and offshore combined) of pink shrimp (Penaeus duorarum duorarum) from the Tortugas fishery (statistical areas 1 and 2 combined) from 1960 to 1978. Exponents of the models were used as indices to investigate trends in ex-vessel value per shrimp, in size composition, and in ex-vessel value composition of the annual catches during that period. Both the spread in ex-vessel value per shrimp among size categories and the size of shrimp in the annual catches increased from 1960 to 1978. Also, the proportion of the ex-vessel value made up of shrimp of larger sizes increased from 1960 to 1978. This approach to analysis of catch statistics can be used to monitor the fishery, and the results can be compared with changes that may be brought about by permanently closing the Tortugas shrimp sanctuary in 1981, as proposed by the Gulf of Mexico Fishery Management Council in the fishery management plan for the shrimp fishery of the Gulf of Mexico

Trends in Ex-Vessel Value and Size Composition of Reported May - August Catches of Brown Shrimp and White Shrimp from the Texas, Louisiana, Mississippi, and Alabama Coasts, 1960-1978

Exponential models were used to characterize (1) ex-vessel value (in dollars) per shrimp by size category (count; i.e., number of shrimp per pound, heads off); (2) size composition (expressed as cumulative weight of the catch in pounds, heads off, by size category); and (3) ex-vessel value composition (expressed as cumulative ex-vessel value, in dollars, of the catch by size category) for reported May-August catches (inshore and offshore combined) of brown shrimp (Penaeus aztecus) and white shrimp (P. setiferus) from the Texas, Louisiana, Mississippi, and Alabama coasts (statistical areas 10-21) from 1960 to 1978. Exponents of the models were used as indices to investigate trends in ex-vessel value per shrimp, size composition, and ex-vessel value composition of the May-August catches during this period. This approach to analysis of catch statistics can be used to monitor these fisheries, and the results can be compared with changes that may be brought about by the closure of the fishery conservation zone off Texas, as proposed by 1981 by the Gulf of Mexico Fishery Management Council, in the fishery management plan for the shrimp fishery of the Gulf of Mexico

Trends in Ex-Vessel Value and Size Composition of Reported Annual Catches of Pink Shrimp from the Tortugas Fishery, 1960-1978

Exponential models were used to characterize (1) ex-vessel value (in dollars) per shrimp by size category (count; i.e., number of shrimp per pound, heads off), (2) size composition (expressed as cumulative weight of the catch in pounds, heads off, by size category), and (3) ex-vessel value composition (expressed as cumulative ex-vessel value, in dollars, of the catch by size category) for reported annual catches (inshore and offshore combined) of pink shrimp (Penaeus duorarum duorarum) from the Tortugas fishery (statistical areas 1 and 2 combined) from 1960 to 1978. Exponents of the models were used as indices to investigate trends in ex-vessel value per shrimp, in size composition, and in ex-vessel value composition of the annual catches during that period. Both the spread in ex-vessel value per shrimp among size categories and the size of shrimp in the annual catches increased from 1960 to 1978. Also, the proportion of the ex-vessel value made up of shrimp of larger sizes increased from 1960 to 1978. This approach to analysis of catch statistics can be used to monitor the fishery, and the results can be compared with changes that may be brought about by permanently closing the Tortugas shrimp sanctuary in 1981, as proposed by the Gulf of Mexico Fishery Management Council in the fishery management plan for the shrimp fishery of the Gulf of Mexico

Ex-Vessel Value and Size Composition of Reported May - August Catches of Brown Shrimp and White Shrimp from 1960 to 1981 as Related to the Texas Closure

Indices were used to test for trends in ex-vessel price spread (value per shrimp by size category), size composition, and ex-vessel value composition of the reported May-August catches (inshore and offshore combined) of brown shrimp (Penaeus aztecus) and white shrimp (P. setiferus) from the Texas coast, the Mississippi River to Texas, and Pensacola to the Mississippi River, from 1960 to 1981. Levels of reported May-August catch and ex-vessel value of the catch also were examined for the same period. Statistical tests were conducted to determine if 1981 was an outlier as compared to other years, in the context of impacts of closure of the fishery conservation zone (FCZ) off Texas to shrimping from May 22 to July 15, 1981, a management measure referred to as the Texas Closure

Trends in Ex-Vessel Value and Size Composition of Reported May - August Catches of Brown Shrimp and White Shrimp from the Texas, Louisiana, Mississippi, and Alabama Coasts, 1960-1978

Exponential models were used to characterize (1) ex-vessel value (in dollars) per shrimp by size category (count; i.e., number of shrimp per pound, heads off); (2) size composition (expressed as cumulative weight of the catch in pounds, heads off, by size category); and (3) ex-vessel value composition (expressed as cumulative ex-vessel value, in dollars, of the catch by size category) for reported May-August catches (inshore and offshore combined) of brown shrimp (Penaeus aztecus) and white shrimp (P. setiferus) from the Texas, Louisiana, Mississippi, and Alabama coasts (statistical areas 10-21) from 1960 to 1978. Exponents of the models were used as indices to investigate trends in ex-vessel value per shrimp, size composition, and ex-vessel value composition of the May-August catches during this period. This approach to analysis of catch statistics can be used to monitor these fisheries, and the results can be compared with changes that may be brought about by the closure of the fishery conservation zone off Texas, as proposed by 1981 by the Gulf of Mexico Fishery Management Council, in the fishery management plan for the shrimp fishery of the Gulf of Mexico

Early Growth in Weight of Kemp\u27s Ridley Sea Turtles (Lepidochelys kempii) in Captivity

Growth in individual weight (w, kg) of Kemp’s ridley sea turtles (Lepidochelys kempii) in captivity was described for 15 year-classes (1978-1992) of turtles between ages (t) 0.17 to 1.22 yr, using In linear regression: Inw = lnc + dt1/2, where Inc is the intercept and d is the slope (growth rate index). There was significant (P \u3c 0.001) heterogeneity in d among year-classes, with slowest growth (d = 3.798) exhibited by the 1983 year-class and fastest growth (d = 6.929) by the 1985 year-class, but there was no significant trend in d (P = 0.307) over year-classes. The variance of residuals from regression, s2reg, ranged from 0.2032 for the 1978 year-class to 0.0075 for the 1992 year-class, and showed a significant (P = 0.0001) logarithmic decrease over the year-classes. This decline in variation among individuals was probably due to a a shift toward sex ratios dominated by one sex (females), improvements in rearing facilities, year-around control of seawater temperature which reduced disease incidence, improved diet, and reduced feeding levels. The relationship between w and scl (straight carapace length) was also described

Dry weather induces outbreaks of human West Nile virus infections

<p>Abstract</p> <p>Background</p> <p>Since its first occurrence in the New York City area during 1999, West Nile virus (WNV) has spread rapidly across North America and has become a major public health concern in North America. By 2002, WNV was reported in 40 states and the District of Columbia with 4,156 human and 14,539 equine cases of infection. Mississippi had the highest human incidence rate of WNV during the 2002 epidemic in the United States. Epidemics of WNV can impose enormous impacts on local economies. Therefore, it is advantageous to predict human WNV risks for cost-effective controls of the disease and optimal allocations of limited resources. Understanding relationships between precipitation and WNV transmission is crucial for predicting the risk of the human WNV disease outbreaks under predicted global climate change scenarios.</p> <p>Methods</p> <p>We analyzed data on the human WNV incidences in the 82 counties of Mississippi in 2002, using standard morbidity ratio (SMR) and Bayesian hierarchical models, to determine relationships between precipitation and human WNV risks. We also entertained spatial autocorrelations of human WNV risks with conditional autocorrelative (CAR) models, implemented in WinBUGS 1.4.3.</p> <p>Results</p> <p>We observed an inverse relationship between county-level human WNV incidence risk and total annual rainfall during the previous year. Parameters representing spatial heterogeneity in the risk of human exposure to WNV improved model fit. Annual precipitation of the previous year was a predictor of spatial variation of WNV risk.</p> <p>Conclusions</p> <p>Our results have broad implications for risk assessment of WNV and forecasting WNV outbreaks. Assessing risk of vector-born infectious diseases will require understanding of complex ecological relationships. Based on the climatologically characteristic drought occurrence in the past and on climate model predictions for climate change and potentially greater drought occurrence in the future, we suggest that the frequency and relative risk of WNV outbreaks could increase.</p