Correlations between body length and otolith size in smallmouth bass Micropterus dolomieu Lacépède, 1802 with implications for retrospective growth analyses

Reconstructing individual growth history from analysis of increments in otoliths, scales, or spines can provide information on past growth responses to environmental variation, which in turn can be useful for predicting population‐level response to climate change. The objective of this study was to examine correlations between body length and different metrics of otolith size for Micropterus dolomieu. Three metrics corresponding to commonly‐used microstructural and ultrastructural otolith dimensions were measured using image analysis of digital micrographs from a sample of 214 M. dolomieu ranging from 115 to 438 mm total length collected in 2011–2013. It was found that anteroposterior length of whole otoliths provided much improved regression relationships with body size as well as ease of data collection and faster sampling throughput compared with microstructural measures from polished sections. When applying these metrics to reconstruct growth history the biological intercept model generally produced more reasonable back‐calculated estimates of length‐at‐age, although this was not consistent across all otolith metrics. Results suggest that whole otolith measures should be employed due to efficiency of data collection and greater reliability for reconstructing growth history in M. dolomieu.     

Age,growth and reproduction of non‐native largemouth bass Micropterus salmoides (Lacépède, 1802) populations in two temperate African impoundments

This study aims to improve the understanding of the establishment success of Micropterus salmoides by assessing growth, maturity and reproductive seasonality of two populations from the temperate region in South Africa. Results are compared to those from other populations to test previously proposed hypotheses that the (i) extent of the spawning season, (ii) longevity, and (iii) growth performance are environmentally temperature dependent. Micropterus salmoides were sampled monthly between March 2010 and March 2012 from Wriggleswade and Mankazana impoundments using either angling or multi‐meshed (35, 45, 47, 57, 65, 73, 77, 93, 106, 118, 150 and 153 mm) multifilament gillnet fleets, and a 1 m seine net. The assessed populations in South Africa performed as expected compared to other introduced populations. Age at maturity (1.3–2 years) and length at maturity (232–254 mm FL) were similar to other temperate populations. A well‐defined, spring spawning season conformed to findings in other temperate populations. Using sectioned sagittal otoliths it was shown that fish were long‐lived (14 years). Growth rates differed significantly between the two assessed populations but both were slower growing than tropical and subtropical introduced populations. Growth performance (Φ′: 2.77–2.99) was similar to other temperate populations. These results indicate that the biology of introduced M. salmoides populations in South Africa is comparable to those of other temperate populations and supports the environmental temperature‐dependent hypothesis.     

Estimation of largemouth bass,Micropterus salmoides Lacépède,growth using the liver somatic index and physiological variables*

Stepwise regression models utilizing five easily-measured condition indices, two physiological variables and two environmental variables were developed for estimating the monthly growth of age-I and II largemouth bass sampled during 1980 and 1982. The liver-somatic index (LSI) and standard metabolism at surface and thermocline temperatures were the most significant variables for estimating growth. Determination of monthly growth using the LSI requires 50% fewer samples than the usual method of following changes in monthly mean weight. Because the LSI responds relatively rapidly to levels of energy intake and temperature, this index can be used to signal possible adverse effects on fish before changes in growth can be observed. This approach could be a useful management tool because, once validated for a particular aquatic system, frequent cost-effective growth estimates could be used to identify the presence of ecological perturbations and to quantify their effect.     

Tooth replacement in the teleost fish Prionurus microlepidotus Lacépède

Previous studies on tooth replacement in lower vertebrates have been plagued by a lack of common integrative approaches and methods, making it impossible to furnish a phylogenetic synthesis. This study is based on serial sections of the jaw of Prionurus microlepidotus. Each Toothgerm was characterized by its developmental stage and its position in the jaw. The relationship between the developmental stage of toothgerm and position in the jaw has been studied and expressed in several graphical illustrations. The following conclusions have been made: (1) The initiation of toothgerms in P. microlepidotus is governed by two Zahnreihen, which respectively initiate toothgerms on the lingual and labial side of the functioning teeth in an alternating pattern. (2) Therefore, functioning teeth in one locus are supplied by the alternate eruption of lingual and labial toothgerms. (3) Advancing of tooth replacement in each locus is independent of functioning teeth and their successors in adjacent loci. (4) The disorders of replacement patterns are caused by an alternated rate of eruption of successive toothgerms as a response to unusual shedding of the functioning teeth.     

Trypanosoma catostomi n. sp. from the White Sucker Catostomus c. commersoni (Lacépède)*

SYNOPSIS. Trypanosoma catostomi n. sp. is described from the blood of the white sucker Catostomus c. commersoni (Lacépède) from southeastern Michigan. Two methods of fixation, wet and dry, are compared for their effect on body measurements. The type of fixation used affects the length of the free flagellum. Significance of this finding is discussed.     

Allozyme differentiation and relationships within Hypostomus Lacépède, 1803 (Osteichthyes: Loricariidae) from the upper Paraguay River basin, Brazil

Nine hypostomine populations from Manso Reservoir (Rio Manso and Rio Cuiabá, upper Paraguay River basin, Brazil) were surveyed using allozyme electrophoresis. Three, sampled at the same sites, were not identified to the species level and were designated as Hypostomus sp. 1, Hypostomus sp. 2 and Hypostomus sp. 3. The survey resulted in 25 loci from 14 scored enzyme systems. Allozyme data allowed diagnostic marker recording for all species analyzed, including the undescribed taxa. Mean expected heterozygosity values were quite variable, ranging from 0.029 to 0.079. Hypotheses to explain this variation are discussed. The allelic frequencies and Nei's genetic identity values showed that Hypostomus sp. 1, Hypostomus sp. 2 and Hypostomus sp. 3 should be considered true biological species, and distinct from the other five Hypostomus species and Pterygoplichthys anisitsi.     

A New Species of Kudoa (Myxosporidea: Chloromyxidae) from the Spot,Leiostomus xanthurus Lacépède,in Clear Lake,Texas*

SYNOPSIS. Kudoa branchiata sp. n. (Myxosporidea: Chloromyxidae) is described from the gills of the marine sciaenid fish, Leiostomus xanthurus Lacépède, from Clear Lake, Texas. Twelve of the 429 hosts examined from 10 September 1970 to 28 April 1971, were infected. Eight of the 12 infected fish were collected in February and March 1971—a period during which only 13% of the total host sample was taken. The mean total length of infected hosts was 149 mm, with a range of 112–185 mm. The mean number of myxosporidean cysts per infected host was 3.5, with a range of 1–11.     

Optimization of the culture methods for nursing Chinese black sleeper (Bostrychus sinensis Lacépède, 1801) fry using an orthogonal array design

Chinese black sleeper (Bostrychus sinensis) is a burrow‐dwelling fish found in intertidal mudflats. As a commercially important fish in southern China, the nursing of B. sinensis fry is a critical step for its farming. The growth and survival of B. sinensis fry are closely related to the stocking density, shelter and diet. In this study, 1575 healthy fry were used to investigate the effects of three factors, namely: diet, stocking density, and shelter on the survival rate (SR), specific growth rate (SGR) and condition factor (CF). The optimal combinations of three levels of each of these three factors (A1‐3, B1‐3 and C1‐3) were also determined, using an orthogonal array design of OA₉ (3⁴). After 50 days of nursing, the results showed that: (i) the best combinations for the three factors at their optimal levels were A1B1C2 or A1B1C3; (ii) factor A was the most important factor and had significant effects (P < 0.05) on the SR and SGR of the fry, while the other factors had no significant effects (P > 0.05); (iii) the SGR, SR and CF of fry fed with commercial formulated feed (CFF) were significantly higher (P < 0.05) compared to those of fry fed with minced trash fish (MTF); and (iv) the fry fed with MTF mixed with antimicrobial peptides (MTF+AMP) showed higher SGR, SR and CF than those fed with MTF alone, which indicated that the antimicrobial peptides had positive effects on the growth and survival of the fry.     

Critical thermal maxima of juvenile alligator gar (Atractosteus spatula,Lacépède, 1803) from three Mississippi‐drainage populations acclimated to three temperatures

Local adaptation may cause thermal tolerance to vary between nearby but distinct populations of a species. During the summer of 2013, alligator gar Atractosteus spatula spawned from broodstock collected from three populations within the Mississippi River drainage separated by a 5° latitudinal gradient were acclimated to three temperatures (25, 30, and 35°C). Ten fish from each population were acclimated at each temperature. CT_Max was determined at each temperature for each population, using five fish for each population‐acclimation temperature pairing. CT_Max for each population‐acclimation temperature pairing was compared using two‐factor anova . CT_Max increased significantly with acclimation temperature (F_2,40 = 600.5, P < 0.001) but population had no significant effect (F_2,40 = 1.882, P = 0.166). Temperature tolerance appears to be consistent across populations of alligator gar, with no evidence of local adaptation.     

Historical record of an alligator gar,Atractosteus spatula (Lacépède, 1803), captured on the floodplain of the Middle Mississippi River at Columbia,Illinois, USA

Historical photographs, newspapers, and interviews can provide useful information on the abundance, distribution, and habitat use of rare fish species and can be useful in the development of conservation and management plans for target species. We report on the historical occurrence of Atractosteus spatula (alligator gar) on the Middle Mississippi River (MMR) floodplain near Columbia, Illinois (Monroe County), approximately 280.5 river kilometers above the Ohio River (River Mile 168) during the spring of 1937. Based on measurements taken from a photograph of a captured specimen and Mr. Paul Lopinot's recollection of the specimen's weight, the alligator gar was approximately 2.0 m total length and weighed 60 kg. An additional 25–30 large alligator gar were observed on the floodplain approximately 3.6 km from the river. The loss of seasonally inundated floodplain habitat due to construction of an extensive agricultural levee system on the MMR may be a contributing factor to the decline of the alligator gar in the northern portion of its range.     

Mesure des déclins de l'intensité et de l'anisotropie de fluorescence du pérylène en présence de membranes d'érythrocyte de pigeon: Comparaison avec un milieu isotrope visqueux

Using synchrotron radiation as the excitation light, we studied the fluorescence parameters of perylene incubated with pigeon erythrocyte membranes and with an isotropic viscous medium, the Primol 342 oil.From 4 to 37°C, we observed a single lifetime of 4.5 ns in the oil and two with the membrane (τ₁ = 1−1.4 ns and τ₂ = 5.4−6.1 ns). The dependence upon temperature of the rotation correlation time of perylene () in the oil was characteristic of an isotropic medium, whereas the limiting value of anitropy (r ∞) was zero. With the membrane, γ ∞ decreased from 0.14 to 0.06 and from 2.9 to 0.5 ns, indicating a greater amplitude and frequency of molecular motions.The addition of chlorpromazine, indomethacine, tetracaine, n-octylamine, octanol or octanoic acid to the membrane decreased the τ₁ and τ₂ values. This would stem from the desorganization of the membrane induced by the drugs.     

Accumulations osseuses en périphérie de terriers de petits carnivores : les stigmates de prédation et de fréquentation

Faunal remains from spoil heaps of two burrows inhabited by small carnivores (fox and badger) are analysed from a taphonomical point of view. This analysis provides characteristics for bone accumulation produced by small carnivores and will be a powerful tool for deciphering site formation about the occupational alternation of small carnivores and humans. Identified species were grouped by size classes. Faunal spectrum is composed by varied species of microfauna (70%), mesofauna (30%). Macromammal remains are under represented (less than 1%) and come from scavenged carcasses. Predators and consumed species are compared on the basis of the skeletal part representation, age classes and recording of predation marks (gnawed and digested bones). Skeletal part representation shows that all taxons exhibit a low-representation of axial skeleton and autopodial bones. Predators show a high representation of hind limb bones and a low representation of the fore limb bones whereas consumed species exhibit a reverse pattern. Mortality curve analysis provides an attritional profile for carnivores and helps for the establishment of the season of occupation of the burrow. Adults largely dominate consumed species. Moreover, predation marks are found in 1% of the carnivores’ bones and from 15% to more than 40% on prey bones. The large-sized prey bones only wear gnawed marks (20%) and anthropic marks (10–20%) whereas microfaunal remains exhibits more digested marks (40%) than gnawing stigmata (5%). Medium-sized animals bones wear both marks and with the same proportions (10–15%).