Condition Factor

Tras generalizarse en los últimos años la cooperación empresarial como estrategia de crecimiento, las investigaciones se han centrado en analizar los motivos que llevan a las empresas a cooperar así como los principales factores que influyen en el funcionamiento de las alianzas. Con este trabajo pretendemos realizar una revisión de la literatura y recoger la clasificación de alianzas según su estructura organizativa que se hace desde la Economía de los Costes de Transacción. De este modo, analizaremos las principales características de los acuerdos contractuales y de capital, destacando a las empresas conjuntas o joint ventures debido a su importancia. Al mismo tiempo se realizará un estudio comparativo de ambas estructuras que nos pongan de manifiesto cuales son los requisitos idóneos ante los que alcanzan su máxima eficiencia. De este modo estaremos sentando las bases para realizar un posterior trabajo empírico que trate de contrastar esas relaciones, tanto en sectores intensivos en tecnología, donde se centra la mayor parte de la investigación en esta materia, como en otros donde la tecnología juegue un papel menos importante.

Resumen: La alta volatilidad que rodea la actividad económica aumenta la dificultad de que las empresas puedan competir de forma aislada en el mercado global. De este modo, en las dos últimas décadas se han generalizado los acuerdos cooperativos. Nuestro objetivo es integrar en el estudio de la cooperación empresarial la estrategia genérica de la empresa y, más concretamente, su capacidad de adaptación a los cambios del entorno. Además, evaluaremos la influencia de los objetivos perseguidos con la cooperación empresarial en su éxito. De este modo, pretendemos demostrar que todos los aspectos relacionados con el desarrollo de un acuerdo cooperativo deben estar coordinados y respetar los principios básicos de la estrategia empresarial para alcanzar su máxima eficiencia. La mayor parte de los estudios empíricos existentes se centran en sectores altamente tecnológicos, por lo que ante esta laguna en la investigación, aplicamos nuestra investigación a un sector maduro no intensivo en tecnología como es el sector agroalimentario español.

La necesidad de las empresas de aumentar su dimensión para ser competitivas ante la alta volatilidad del entorno ha provocado la generalización de la cooperación empresarial en los últimos años. Como consecuencia existen numerosos estudios relativos a dicha estrategia, donde los aspectos más analizados han sido los factores claves de éxito y las ventajas de la cooperación empresarial, destacando los análisis empíricos realizados en sectores intensivos en tecnología. Sin embargo, la cooperación también tiene importantes riesgos asociados, por lo que, nuestro objetivo será realizar un estudio exploratorio donde se analice de forma conjunta los motivos que llevan a las empresas a cooperar y, por tanto, las ventajas que se derivan de la cooperación, y sus riesgos asociados. Frente a los análisis centrados en la cooperación basada en la innovación tecnológica, consideramos necesario aportar información sobre los acuerdos cooperativos en sectores de baja intensidad tecnológica, claves en el empleo y la economía tanto en España, Colombia y demás países con un sector agroalimentario importante. Palabras clave: acuerdos de cooperación, motivos, riesgos, éxito del acuerdo Abstract The need of the companies to increase their size to be competitive because of the high volatility of the environment has provoked the generalization of the cooperation agreements in the last years. Because of that have been done numerous studies relative to the above mentioned strategy, where the most analyzed aspects have been the key factors of success and the advantages of the managerial cooperation, emphasizing the empirical analyses made in intensive sectors in technology. Nevertheless, the cooperation also has important associate risks, for what, our aim will be to carry out an exploratory study where we analyse jointly the reasons by which enterprises cooperate and, therefore, the cooperation advantages and his associate risks. Opposite to the researches centred on the cooperation based on the technological innovation, we consider necessarily to investigate about the cooperation agreements, key of low technological intensity in the employment and the economy so much in Spain, Colombia and other countries with a food-processing important sector.

Resumen: La alta volatilidad que rodea la actividad económica aumenta la dificultad de que las empresas puedan competir de forma aislada en el mercado global. De este modo, en las dos últimas décadas se han generalizado los acuerdos cooperativos. Nuestro objetivo es integrar en el estudio de la cooperación empresarial la estrategia genérica de la empresa y, más concretamente, su capacidad de adaptación a los cambios del entorno. Además, evaluaremos la influencia de los objetivos perseguidos con la cooperación empresarial en su éxito. De este modo, pretendemos demostrar que todos los aspectos relacionados con el desarrollo de un acuerdo cooperativo deben estar coordinados y respetar los principios básicos de la estrategia empresarial para alcanzar su máxima eficiencia. La mayor parte de los estudios empíricos existentes se centran en sectores altamente tecnológicos, por lo que ante esta laguna en la investigación, aplicamos nuestra investigación a un sector maduro no intensivo en tecnología como es el sector agroalimentario español.

Tras generalizarse en los últimos años la cooperación empresarial como estrategia de crecimiento, las investigaciones se han centrado en analizar los motivos que llevan a las empresas a cooperar así como los principales factores que influyen en el funcionamiento de las alianzas. Con este trabajo pretendemos realizar una revisión de la literatura y recoger la clasificación de alianzas según su estructura organizativa que se hace desde la Economía de los Costes de Transacción. De este modo, analizaremos las principales características de los acuerdos contractuales y de capital, destacando a las empresas conjuntas o joint ventures debido a su importancia. Al mismo tiempo se realizará un estudio comparativo de ambas estructuras que nos pongan de manifiesto cuales son los requisitos idóneos ante los que alcanzan su máxima eficiencia. De este modo estaremos sentando las bases para realizar un posterior trabajo empírico que trate de contrastar esas relaciones, tanto en sectores intensivos en tecnología, donde se centra la mayor parte de la investigación en esta materia, como en otros donde la tecnología juegue un papel menos importante.

Maturity size and fecundity of hybrid tilapia Oreochromis aureus X Oreochromis niloticus. (Pisces: Cichlidae) from the reservoir Fernando Hiriart Balderrama "Zimapan", Hidalgo, Mexico were determined in organisms caught between 2007 and 2008. A total of 506 hybrid fishes were captured and showed a range of sizes from 20 to 28,9 cm standard length (S L), and total weight of 200 to 750g (T w). The estimated maturation size for females was 20,8cm and 22cm for males, respectively. Fecundity was estimated on 50 gonads and a mean of 3 113±1 826 eggs was recorded per gravid female. Based on these results, these fishes are suitable for commercial exploitation and imply good conservation in correlation to the regulatory strategies for fisheries established in the area, at least from a reproductive point of view.

The authors describe the use of a stress process model by the East Side Village Health Worker Partnership (ESVHWP), a project of the Detroit Community-Academic Urban Research Center, as a framework for understanding social determinants of health. Specifically, the authors describe the development by the ESVHWP Steering Committee of a context-specific stress process model for east side Detroit residents. The authors examine data from in-depth interviews to illuminate actions taken by community members to reduce stressors or minimize their impact on health. Finally, the authors describe the use of this context-specific stress process model and data gathered regarding actions to address community stressors to inform the development of interventions by the ESVHWP to reduce stressors or strengthen the conditioning factors that reduce the impact of stress on health. On the basis of these results, the authors discuss opportunities and challenges for partnership approaches to addressing social determinants of health in urban communities. Differentials in morbidity and mortality on the basis of socioeconomic status have been firmly established by several decades of research carried out across countries, regions, and political economies. These socioeconomic disparities account for much of

Developing shrimp to a commercial size in a confined freshwater space is important because it saves food and because predators and diseases are avoided. Our study was conducted to calculate the growth of white shrimp Litopenaeus vannamei by hyper-intensive farming in fresh water from 0,5 to 5‰ and under semi-controlled conditions. We seeded at a density of 563 postlarvae/m 3 or m 2 during the first cycle and 400 postlarvae/m 3 in the second cycle in an outdoor pond of 6m 3 or m 2 covered with a mesh. Aeration was constant, they were fed Daphnia magna during the first two weeks and then camaronina pellets containing 35% protein, in food baskets, as demanded. The temperature ranged from 22,3 to 31,3°C, pH between 7,5 and 8,7, the oxygen was 4,26±1,43mg/L; the ponds were cleaned of debris every other day, and water was changed according to a program. The food conversion factor (FCA) was 1:1,1. The shrimp were measured weekly to calculate growth using the Bertalanffy model. Survival in the first cycle was 88,1 and 95,8% for the second cycle. Population parameters by maximum likelihood method of the first cycle were k=0,0957, L∞ =146,98 and t 0 =-0,93; in the second cycle k=0,0172, L∞ =367,82 and t 0 =-4,60. The results indicate rapid growth during the first ten weeks. Biomass was obtained from 26kg for the first cycle and 16kg for the second cycle.

Zinc oxide nanoparticles (nano-ZnO) are used in the production of transparent sunscreens and cosmetics, which are released into the environment through municipal effluents. The purpose of this study was to examine the toxicity of nano-ZnO to freshwater mussels (Elliptio complanata) in the presence of municipal effluents. Mussels were exposed for 21 days at 15 o C to 1 and 10 µg/L nano-ZnO, and ZnCl 2 in the presence of a physico-chemically treated municipal effluent (3 and 10 % v/v). After the exposure period and a 24 h depuration step, mussels were analyzed for free Zn in gills, metallothioneins (MT), oxidative stress (production of malondialdehyde (MDA) during lipid peroxidation), gonad alkali-labile phosphate (ALP) levels and genotoxicity. Gill MT levels were increased at 10 µg/L nano-ZnO and ZnCl 2 and in the presence of the municipal effluent. MT levels were positively correlated with free Zn in gills and negatively correlated with MDA levels, indicating its involvement in the prevention of oxidative stress. However, MDA levels were significantly related to DNA damage in gills, indicating that MT induction did not prevent oxidative-mediated damage in cells. Gonad ALP levels were increased by exposure to ZnCl 2 and to the highest concentration of municipal effluent. DNA strand breaks were increased in mussels treated to nano-ZnO indepentely of municipal effluent. Multivariate discriminant function analysis revealed that control mussels differed from mussels exposed to the municipal effluent and from those exposed to nano-ZnO or ZnCl 2 alone. When the municipal effluent was added, changes in MDA, MT and labile Zn were produced and formed another cluster, suggesting a change in the toxicity of the municipal effluent in the presence of nano-ZnO.

Sinkholes disrupt transportation route serviceability causing significant direct and indirect economic losses. Additionally, catastrophic collapse sinkholes may lead to accidents producing loss of human lives. Sinkhole risk modelling allows the estimation of the expectable losses in different portions of infrastructures and the identification of the sections where the application corrective measures would have a better cost-benefit ratio. An example of sinkhole risk analysis applied to a motorway under construction in a mantled evaporite karst area with a very high probability of occurrence of cover collapse sinkholes is presented. Firstly, sinkhole susceptibility models have been obtained, and independently evaluated, on the basis of a probabilistic method which combines the distance to nearest sinkhole with other conditioning factors. The most reliable susceptibility model was then transformed into several sinkhole hazard models using empirical functions. This functions describe the relationships between the frequency of sinkholes and (1) sinkholes dimensions, (2) terrain susceptibility and (3) land cover. Although to evaluate hazard models more information on temporal occurrences would be needed, the quality and quantity of the data in which models are based and the distribution of the latest sinkholes of considerable magnitude occurred in the study area indicate that the models seem to be sound. Two collapse sinkholes 4 m across formed after the production of the models coincide with the zone of highest hazard, which occupy 15% of the study area. Finally, on the basis of the hazard models obtained, sinkhole risk models were generated for a motorway under construction with the aim of quantitatively estimating the expected losses in different sections of the infrastructure in a given period of time. To produce the risk models, the vulnerability of the motorway was estimated considering the cost of the structure, sinkhole magnitude and frequency and the expectable damage based of past events. The described procedure constitutes a useful tool to identify the sections of linear infrastructures (roads, railways, canals) where the application of structural corrective measures should be of top priority and may be also used to foresee the time needed to pay off mitigation measures by means of cost-benefit analyses.

The pikeperch Sander lucioperca (L.) is present in numerous French water bodies. However, few studies have focused on the biology and ecology of the species and, as a result, references are lacking to assess its adaptation to lacustrine environments. The growth and diet of pikeperch were investigated in two reservoirs located in southern France. The fish at both sites show similar growth rates to those reported in other European countries, but slower than those observed in the Camargue. It is faster in the warm, eutrophic waters of the Treignac Reservoir than in the deeper, oligotrophic waters of Castillon Reservoir. A late shift to piscivory with strong cannibalism was observed at both sites, and the condition factors were low. These elements suggest successful adaptation to these environments though shortages of prey fish are likely to occur.

Growth and reproductive biology of largemouth bass was investigated to study aspects of its biology as well as possible effects upon other ®sh species as a result of its introduction to Lake Trasimeno. From April 1993 to May 1994, 182 specimens (87 males, 83 females, 12 sexually indeterminate) distributed among seven age classes were captured. The length±weight regression was W 0:00988LT 3:1512AE0:027 (males) and W 0:00888LT 3:184AE0:032 (females) without any signi®cant differences between sexes. The growth of the 1age-class is not continuous throughout the year; it slows to almost nothing in the winter. The parameters of the von Bertalanffy growth curve for length were L I 46:88, K 0:33 and t 0 0:056 for the females and L I 39:4, K 0:42 and t 0 0:019 for the males. The condition factor indicates that the Lake Trasimeno population is in excellent condition. Reproduction occurs mostly in May. Sexual maturity is reached at 2 years for males and 3 years for females, at lengths and weights of 22 cm and 160 g for males and 30 cm and 397 g for females, respectively. Largemouth bass has adapted well to Lake Trasimeno where physical and trophic conditions favour growth and reproduction.

T wo princ ipal sport fi sh-th e indi genous Bonnev ill e cutth roa t trout Oncorhynchus clarki IItah and the introdu ced lake trout Salvelinl/s namaycush-are the do min ant pi sc ivores in Bea r Lake, a 282-km 2 o li gotrophic sys tem. These pi scivo res re ly predo min antl y on fo ur e nde mi c prey fi sh species that make up a maj o r porti on of the uniqu e Bear Lake fi sh as e mblage. We estimated the annu a l bi o mas o f pe lag ic and benthi c prey fi sh by us in g hydroaco usti c and trawling tec hniques . We also estim ated th e lakew ide abundance of pi scivores with a multiple mark-reca pture s ur vey and used a bi oenergeti cs mode l to compare th e pop ul ati on-level co nsumpti on of prey fi sh wi th prey fi h producti on. Prey fi sh bi o mas s dec lined to a minimum durin g 199 1 and 1992 but s ubseque ntl y recovered to reach max imum levels durin g 1994 a nd 1995 . The proporti on of maximum rati on estim ates fro m mode l s imul ati ons indica ted th at the pi sc ivores were co nsumin g we ll be low max imum rati ons durin g a peri od when predati o n exceeded prey fi sh produ cti on, th ereby pro vidin g th e potenti al fo r a predator-prey imbalance. Predati on impacts by lake tro ut co horts were pro lo nged beca use of hi gh sur vivorship and long li fe ex pec tancy. Altho ugh cutthroat trout outnumbered lake trout , the larger, more pi scivoro us s ize-c lasses of c utth roa t trout acco unted fo r onl y 12.5 % of th e ir populati on. This in fo rm ati o n, com bined with overl apping di ets and declining co nditi on fac tors at in creased pi scivore bi o mass, also indi ca tes that lake tro ut may be co mpetin g with cutth roa t trout durin g peri ods o f low prey fi sh resources. Lake tro ut predati on on juve nil e c utthroat tro ut, co mbin ed with co mpetiti on with other age-c lasses, a lso contributes to th e poo r sur viva l of cutth roat tro ut. Altho ugh prey fi sh abundance appears to be largely influ enced by botto m-up fac tors re lated to wa te r e leva ti o n, lake tro ut exert a decoupled predatory threat to th e e nde mi c prey fi sh populati ons and have the potentia l to suppress e nde mi c fis hes durin g unpredi ctabl e peri ods of poo r prey fi sh produc ti on.

The effects of personalization of survey invitations on response rates have been extensively researched in the realm of mail surveys. Commonly, it is found that response rates increase when personalization is applied. Recently, efforts have been made to investigate whether these ...

Neretvanski strugač (Squalius svallize) je endemska vrsta koja naseljava vodotoke Jadranskog slijeva u Bosni i Hercegovini te Hrvatskoj, i to isključivo u rijekama: Neretvi, Trebišnjici i Ljutoj. Strukuktura populacije istraživana je na 60 jedinki ulovljenih pomoću mreža prostirica na tri lokacije: Deransko jezero, rijeka Krupa, rijeka Bregava. Cilj istraživanje je utvrditi dužinsku i masenu strukturu populacije strugača po lokacijama, te odnos između duljine probavila i totalne duljine tijela. Rezultati su prikazani u obliku histograma frekvencija, duljinskih i masenih struktura po lokacijama, te regresijskog odnosa između ukupne duljine tijela i duljine probavila. Dominirale su jedinke s totalnom tjelesnom duljinom 19-20 cm, a maksimalna totalna duljina iznosila je 28 cm. Maksimalna zabilježena masa iznosila je 269,30 g, a prema histogramu frekvencija mase tijela, prevladava maseni razred 60-90 g. Utvrđen je pozitivan alometrijski rast s visokom bvrijednošću od 3,47. Koeficijent korelacije (r=0,83 ** ) govori o pozitivnoj povezanosti između totalne duljine tijela i duljine probavila. Ovim istraživanjem dati su novi rezultati o strukturi poulacije endemskog strugača u vodotocima neretvanskog slijeva.

Neretvanski strugač (Squalius svallize) je endemska vrsta koja naseljava vodotoke Jadranskog slijeva u Bosni i Hercegovini te Hrvatskoj, i to isključivo u rijekama: Neretvi, Trebišnjici i Ljutoj. Strukuktura populacije istraživana je na 60 jedinki ulovljenih pomoću mreža prostirica na tri lokacije: Deransko jezero, rijeka Krupa, rijeka Bregava. Cilj istraživanje je utvrditi dužinsku i masenu strukturu populacije strugača po lokacijama, te odnos između duljine probavila i totalne duljine tijela. Rezultati su prikazani u obliku histograma frekvencija, duljinskih i masenih struktura po lokacijama, te regresijskog odnosa između ukupne duljine tijela i duljine probavila. Dominirale su jedinke s totalnom tjelesnom duljinom 19-20 cm, a maksimalna totalna duljina iznosila je 28 cm. Maksimalna zabilježena masa iznosila je 269,30 g, a prema histogramu frekvencija mase tijela, prevladava maseni razred 60-90 g. Utvrđen je pozitivan alometrijski rast s visokom bvrijednošću od 3,47. Koeficijent k...

Atlantic cod were food-deprived for a period of 84 days at three temperatures (2, 6, 10°C), and changes in the liver, gonads and somatic weights, and muscle and liver water contents were monitored and compared with changes observed in wild cod over winter in the northern Gulf of St. Lawrence. Total lack of food during the period January–April would have caused condition to decline to a level at which very high mortality takes place. Actual changes in condition in wild cod were less than predicted from the laboratory experiments except during the period April–May at the onset of spawning. Thus, wild cod were able to meet part of the metabolic costs during winter through occasional feeding, as confirmed by stomach content data. We conclude that previous estimates of natural mortality associated with poor condition in spring were not biased by the selective mortality of poor-condition fish in winter.

Theoretical models of coastal shark populations have remained largely unchanged since the 1960s despite limitations in applicability to many species. Smaller bodied coastal species are poorly represented by the current models. A new theoretical model is proposed to represent those species that spend most or all of their life within nearshore waters but do not show use of discrete nursery areas. Description of this new model outlines the importance of nearshore areas to these smaller species. While all coastal shark ...

Size frequency, length-weight relationships (LWRs), length-length relationships (LLRs), and relative condition factor (Kn) was studied in an estuarine fish the Bengal yellowfin seabream, Acanthopagrus longispinnis (Val.), from Hatiya Island in the Meghna River estuary. Specimens were caught with fixed purse nets of two mesh sizes (0.2 to 0.5 inch and 2.0 to 2.5 inch) from January to March 2020. The total body length of A. longispinnis ranged between 5.8 and 9.3 cm throughout the sampling period. The length-weight relationships for A. longispinnis was highly significant (p < .001), and the adjusted r 2 value was 0.921. The calculated growth coefficient (b) for A. longispinnis was 3.163, which indicated a hyperallometric growth pattern. The length-length equation TL = 1.1384 SL + 0.4899 for unsexed A. longispinnis was highly significant (p = 0.001, r2 = 0.951). There were no significant variations in relative condition factors among the specimens of different length classes (5.5–9....

Smolting is characterized by morphological and physiological changes, some of which are reversible if fish remain in freshwater. Whether fish that smolt in the first year will repeat physiological changes associated with smolting a second time is not known. To assess whether Atlantic salmon (Salmo salar) can smolt more than once, we sampled hatchery-reared Atlantic salmon at monthly intervals for 2 years beginning the fall after hatching. Fish showed differences in rate of growth and were easily differentiated by size into upper mode (UM) and lower mode (LM) by the first fall. In the first spring, gill Na + ,K + -ATPase activity of UM and LM fish increased six-and three-fold, respectively. Plasma growth hormone levels in spring were significantly elevated in UM fish but not in LM. Plasma cortisol levels changed little and gill corticosteroid receptor concentration did not differ between the groups. During the summer, gill Na + ,K + -ATPase activity declined in both groups and remained low until the next spring. The second spring, growth hormone levels did not increase significantly and cortisol levels increased. The increase in gill Na + ,K + -ATPase activity and cortisol and high saltwater tolerance indicate that UM Atlantic salmon can smolt in two consecutive years. Résumé : La smoltification se caractérise par des changements morphologiques et physiologiques dont certains sont réversibles si les poissons restent en eau douce. Nous ne savons pas si les poissons qui smoltifient la première année vont reproduire une deuxième fois les changements physiologiques associés à la smoltification. Pour déterminer si le saumon atlantique peut subir plus d'une smoltification, nous avons échantillonné des saumons d'élevage à intervalle mensuel pendant deux ans à partir de l'automne qui a suivi l'éclosion. Les poissons présentaient des différences dans le taux de croissance, et étaient faciles à classer par la taille en mode supérieur et en mode inférieur dès le premier automne. Au premier printemps, l'activité de la Na + ,K + -ATPase dans les branchies augmentait respectivement six fois et trois fois chez les poissons de mode supérieur et de mode inférieur. Les niveaux d'hormone de croissance dans le plasma au printemps étaient nettement élevés chez les poissons de mode supérieur, mais pas chez les autres. Les niveaux de cortisol dans le plasma ont peu changé, et la concentration des récepteurs de corticostéroïdes dans les branchies ne variait pas d'un groupe à l'autre. Pendant l'été, l'activité de la Na + ,K + -ATPase dans les branchies baissait chez les deux groupes, et elle est demeurée basse jusqu'au printemps suivant. Au deuxième printemps, les niveaux d'hormone de croissance n'ont pas augmenté de façon significative, mais les niveaux de cortisol ont monté. L'augmentation de l'activité de la Na + ,K + -ATPase dans les branchies et la hausse du cortisol, ainsi que la tolérance à une eau fortement salée, indiquent que les saumons atlantiques de mode supérieur peuvent connaître une smoltification deux années consécutives.

Freshwater and seawater isoforms of the alpha subunit of Na + /K + -ATPase (NKA) have previously been identified in gill ionocytes of Atlantic salmon (Salmo salar). In the present study we examine the abundance and cellular localization of these isoforms during the parr-smolt transformation, a developmental process that is preparatory for seawater entry. The abundance of NKAα1a was lower in smolts than in parr, remained relatively constant during spring and decreased in summer. NKAα1b increased tenfold in smolts during spring, peaking in late April, coincident with downstream migration and increased salinity tolerance. NKAα1b increased a further twofold after seawater exposure of smolts, whereas NKAα1a decreased by 98%. The abundance of NKAα1bpositive, and NKAα1b and NKAα1a co-labeled ionocytes increased during smolt development, whereas the number of NKAα1a cells decreased. After seawater exposure of smolts, NKAα1b-positive ionocytes increased, NKAα1a-positive cells decreased, and co-labeled cells disappeared. Plasma growth hormone and cortisol increased during spring in smolts, but not in parr, peaking just prior to the highest levels of NKAα1b. The results indicate that the increase in the abundance of NKAα1b during smolt development is directly linked to the increase in salinity tolerance that occurs at this stage, but that significant changes also occur after seawater exposure. Spring increases in circulating levels of growth hormone and cortisol indicate that these hormones may be instrumental in upregulating NKAα1b during smolt development.

Smolting is characterized by morphological and physiological changes, some of which are reversible if fish remain in freshwater. Whether fish that smolt in the first year will repeat physiological changes associated with smolting a second time is not known. To assess whether Atlantic salmon (Salmo salar) can smolt more than once, we sampled hatchery-reared Atlantic salmon at monthly intervals for 2 years beginning the fall after hatching. Fish showed differences in rate of growth and were easily differentiated by size into upper mode (UM) and lower mode (LM) by the first fall. In the first spring, gill Na + ,K + -ATPase activity of UM and LM fish increased six-and three-fold, respectively. Plasma growth hormone levels in spring were significantly elevated in UM fish but not in LM. Plasma cortisol levels changed little and gill corticosteroid receptor concentration did not differ between the groups. During the summer, gill Na + ,K + -ATPase activity declined in both groups and remained low until the next spring. The second spring, growth hormone levels did not increase significantly and cortisol levels increased. The increase in gill Na + ,K + -ATPase activity and cortisol and high saltwater tolerance indicate that UM Atlantic salmon can smolt in two consecutive years. Résumé : La smoltification se caractérise par des changements morphologiques et physiologiques dont certains sont réversibles si les poissons restent en eau douce. Nous ne savons pas si les poissons qui smoltifient la première année vont reproduire une deuxième fois les changements physiologiques associés à la smoltification. Pour déterminer si le saumon atlantique peut subir plus d'une smoltification, nous avons échantillonné des saumons d'élevage à intervalle mensuel pendant deux ans à partir de l'automne qui a suivi l'éclosion. Les poissons présentaient des différences dans le taux de croissance, et étaient faciles à classer par la taille en mode supérieur et en mode inférieur dès le premier automne. Au premier printemps, l'activité de la Na + ,K + -ATPase dans les branchies augmentait respectivement six fois et trois fois chez les poissons de mode supérieur et de mode inférieur. Les niveaux d'hormone de croissance dans le plasma au printemps étaient nettement élevés chez les poissons de mode supérieur, mais pas chez les autres. Les niveaux de cortisol dans le plasma ont peu changé, et la concentration des récepteurs de corticostéroïdes dans les branchies ne variait pas d'un groupe à l'autre. Pendant l'été, l'activité de la Na + ,K + -ATPase dans les branchies baissait chez les deux groupes, et elle est demeurée basse jusqu'au printemps suivant. Au deuxième printemps, les niveaux d'hormone de croissance n'ont pas augmenté de façon significative, mais les niveaux de cortisol ont monté. L'augmentation de l'activité de la Na + ,K + -ATPase dans les branchies et la hausse du cortisol, ainsi que la tolérance à une eau fortement salée, indiquent que les saumons atlantiques de mode supérieur peuvent connaître une smoltification deux années consécutives.

In order to elucidate the developmental basis for smolting, Atlantic salmon, Salmo salar, parr (b11.5 cm) and smolts (N 12.5 cm) were exposed to natural daylength (LDN) and increased daylength (LD16:8) starting in late February and gill Na + ,K + -ATPase activity and circulating hormone levels monitored from January to May. Gill Na + ,K + -ATPase activity remained low and constant in both groups of parr. In smolts, gill Na + ,K + -ATPase began increasing in late February in both photoperiods, but was significantly higher in the LD16:8 group from March through April. Smolts exposed to LD16:8 had dramatically elevated plasma GH within one week of increased daylength that remained high through April, whereas plasma GH of LDN smolts increased steadily beginning in late February and peaking in late April. Plasma GH levels of parr remained low in spring and did not respond to increased daylength. Plasma insulin-like growth factor I (IGF-I) levels were substantially higher in smolts than parr in January. Plasma IGF-I levels of parr increased steadily from January to May, but there was no influence of increased daylength. In smolts, plasma IGF-I of LD16:8 fish initially decreased in early March then increased in late March and April, whereas plasma IGF-I of LDN smolts increased steadily to peak levels in early April. Plasma cortisol was low in parr throughout spring and did not differ between photoperiod treatments. Plasma cortisol of LD16:8 smolts increased in early March and remained elevated through April, whereas in LDN smolts plasma cortisol did not increase until early April and peaked in late April. Plasma thyroid hormones were generally higher in smolts than in parr, but there was no clear effect of increased daylength in parr or smolts. The greater capacity of the GH/IGF-I and cortisol axes to respond to increased daylength may be a critical factor underlying smolt development.

The response of the endocrine system to short-term exposure to sea water (SW) was examined before, during and after the Parr-smolt transformation of coho salmon. Five transfers of yearling coho salmon (Oncorhynchus kisutch) from fresh water (FW) to FW, or from FW to SW for 24 h were carried out between March and September. Condition factor declined significantly in late April, and gill Na+, K+-ATPase activity was elevated between late March and early June. Increases in plasma osmolality after transfer to SW were high in early March, low from late March -early June and slightly higher in September. In fish transferred from FW to FW, plasma levels of thyroxine (Td) were elevated in late March-late April, and plasma levels of cortisol were high in late March-early June; both hormones declined to early March levels thereafter. Growth hormone (GH) levels increased in late March and.remained elevated for the duration of the study. A significant linear correlation existed between plasma cortisol and growth hormone levels in FW to FW transferred fish. After SW transfer, T4 levels were significantly lower than values in FW controls in early March and were significantly higher than FW control levels in early June andearly September. Cortisol levels increased significantly after each transfer except in late April. However, compared with the early March and early September transfers, the magnitude of the elevation was reduced in late March. GH levels were significantly elevated above FW control levels after seawater transfer in late April only, despite a trend for mean GH levels to be higher after transfer in June and September. Thus, minimal increases in cortisol, and increases in GH occur after SW transfer of functional (optimally hypo-osmoregulating) smolts.

The pikeperch Sander lucioperca (L.) is present in numerous French water bodies. However, few studies have focused on the biology and ecology of the species and, as a result, references are lacking to assess its adaptation to lacustrine environments. The growth and diet of pikeperch were investigated in two reservoirs located in southern France. The fish at both sites show similar growth rates to those reported in other European countries, but slower than those observed in the Camargue. It is faster in the warm, eutrophic waters of the Treignac Reservoir than in the deeper, oligotrophic waters of Castillon Reservoir. A late shift to piscivory with strong cannibalism was observed at both sites, and the condition factors were low. These elements suggest successful adaptation to these environments though shortages of prey fish are likely to occur.

Larvae of tetraphyllidean cestodes have been recorded in several species of marine teleosts. However, little is known on parasite-host interactions. In view of this, the present study aims at i) determining the localization sites of a larval type, belonging to the Scolex group, in the digestive tract mucose; ii) describing the anatomo-pathological features of the larval lesions produced; and iii) evaluating the potential effect of parasite intensity on the body condition of the host. Our findings reveal that parasitic charges were more intense in the second portion of the digestive tract. In the area of contact between the parasite and the epithelium a compressive atrophy of the cells was observed with a marked lowering and disappearance of the epithelial layer. The condition factor of the samples analyzed was significantly affected by infection intensity, thus revealing an adverse effect on the growth and physical condition of the host.

This article argues that looking solely for the immediate causes of reproductive change may distort our understanding of policy options by failing to take into account the historical and cultural factors that affect not only the impact of policies and programs but their very nature and existence. The article examines the historical origins and spread of “modern” ideas in Bangladesh and the state of West Bengal in India. It concludes that a colonial history in which education and modernization processes took hold very early among the elites in the larger Bengal region was paradoxically accompanied by a strong allegiance to the Bengali language. This strong sense of language identity has facilitated and reinforced the diffusion of modern ideas both within and between the two Bengali‐speaking regions. Thus, to understand the fertility decline in Bangladesh, for example, one needs to look also at cultural boundaries. In this case, the cultural commonality through language facilitates th...

This study identified regions of the Brazilian coast that present more adequate temperature conditions for the cage culture of cobia (Rachycentron canadum). A survey of sea surface temperatures (SST) along the coast (up to the 200 m isobath) used data from the Aqua/NASA satellite. Water temperature classes that affect the development of cobia and may lead to changes in physiological activities, especially related to feed intake, growth, and mortality, were established, according to the literature. Cobia is able to grow at temperatures between 19 and 32 ºC, but the range considered optimum for growth was 27-29 ºC. The coastal area stretching from eastern Pará to the north of Bahia was considered to have the most suitable temperature conditions for commercial aquaculture of cobia. The coastline encompassing the state of Amapá to the west of Pará, and the whole coast of the southeast region presented SSTs above or below the range considered optimum for the growth of cobia, respectively. In the southern coast of Brazil, the commercial farming of cobia may not be feasible due to the low SST during most of the year.

Condition assessment is commonly practiced by fisheries personnel as one tool for evaluating fish populations and communities. Several noninvasive condition measures are available for use, including Fulton's condition factor (K), relative condition factor (Kn), and relative weight (Wr). The use of Wr as a condition measure has increased within several peerreviewed journals. In 1995 to 1996, survey responses from agency personnel in 48 states indicated that 22 states used Wr as a standard technique, 18 states identified Wr use as occasional, whereas only eight states indicated no Wr use. The regression-line-percentile technique is recommended for developing standard weight (Ws) equations. There are currently Ws equations available for 52 species and three purposeful hybrids. Length-related trends in condition need to be evaluated prior to calculating a population mean Wr. Relative weight target ranges should be adjusted to meet specific management objectives. Relative weight values are influenced by seasonal dynamics. The uses of Wr may go beyond just a measure of fish "plumpness." Relative weight can serve as a surrogate for estimating fish body composition, as a measure of fish health, and to assess prey abundance, fish stockings, and management actions.

Metapenaeus monoceros is the second most abundant commercially important
shrimp species caught along the Saudi Arabian Red Sea coast. However, knowledge of its
life history and population dynamics in the region remains limited, posing challenges for
sustainable management. This study assessed the growth, maturity, and mortality of M.
monoceros based on fishery-independent samples collected from shrimp trawling grounds
off Al Qunfudhah and Jizan (October 2022–September 2023). Altogether, 10,859 specimens
were examined, with a carapace length (CL) ranging from 7.98 to 49.10 mm and a total
weight (W) in the range of 0.41 to 41.28 g. The observed sex ratio was 1.56:1 in favor of
females. The CL–W relationship was W = 0.0024·CL2.58. The seasonalized von Bertalanffy
growth parameters were CL∞ = 50.66 mm, K = 0.35 year−1
, tanchor = 0.43 years, C = 0.64,
and ts = 0.61 years for females, and CL∞ = 38.97 mm, K = 0.55 year−1
, tanchor = 0.51 years,
C = 0.84, and ts = 0.39 years for males. Females reached their first sexual maturity at
21.12 mm CL. The exploitation rates (0.60 for both sexes) indicated overfishing. Spawning
potential ratio analysis showed that the current fishing pressure reduces the spawning
stock biomass to 23% of unexploited levels. A 50% reduction in fishing effort, extended
seasonal closures, and selective gear modifications are recommended to rebuild the stock
and ensure sustainability.

Starting in 2007, the American Association of State Highway and Transportation Officials (AASHTO) adopted the Load and Resistance Factored Design (LRFD) Bridge Design Specifications as the mandatory standard by which all future bridge structures should be designed. New Jersey committed itself to adopting the LRFD Specifications in January 2000. The LRFD Specifications consider the variability in the behavior of structural elements through extensive statistical analyses and, therefore, continue to be improved. However, many of the Specifications' design approaches and methodologies have been adopted with limited or virtually no experimental validation. Hence, there became a need to validate these new design procedures and models as well as the behavior of LRFD designed bridge structures. The main objective of this study was to validate the AASHTO LRFD Specifications through fieldtesting of the Doremus Avenue Bridge-New Jersey's first AASHTO LRFD (1998) design. In addition, long-term monitoring of the bridge fatigue life was also implemented. In particular, the study evaluates the AASHTO criteria for composite design with respect to the requirements for shear connectors, the effects of designing for deflection control as well as using higher concrete strengths on deck stiffness and stresses. Results included new simplified equations for calculating Girder Distribution Factors (GDF) and effective flange width criteria in addition to establishing major live load spectra for various WIM NJ sites. Deflection measurements and simulation using Extreme Value Theory (EVT) shows that the 75-year maximum deflection is within the NJDOT deflection limit of L/1000. However, future research is needed to establish if the L/1000 limit is indirectly helping to control vibration of the superstructure. Moreover, a new procedure for predicting the remaining fatigue life is established using WIM truck data, rain flow, and structural analyses.

Résumé. L'étude de la reproduction de Sardina pilchardus a été réalisée sur la base des échantillons prélevés sur les débarquements commerciaux effectués au port de Laâyoune durant la période allant de janvier 1999 à décembre 2001. Cette étude a montré que la ...

This study investigates gonado somatic index, food and feeding habit of selected fish species of Lake Kalgwai Jigawa State, Nigeria. Samples of fish were collected every fortnight (July 2012-June 2013) at three major landing sites of the lake. The weight of each fish was recorded, gonads were removed, weighed and the gonadosomatic index (GSI) calculated. Stomach was also removed and the content analyzed using frequency of occurrence and point method. Result obtained reveals GSI to range from 2.39±0.08% in Nile perch Latesniloticus [1] to 5.92±0.29% in Nile tilapia Oreochromisniloticus . The stomach content analysis in this study distinguished the fish species into two major groups; Latesniloticus, Mormyrusmacrophthalmus Günther, 1866 and Bayad bagrus bayad Forsskål [2] were observed to exhibit carnivorous feeding habits and feed predominantly on crustacean, fish, fish parts, mollusks, insects and insect larvae, Oreochromisniloticus, African bony tongue Heterotisniloticus [3], Electric catfish Malapteruruselectricus, Synodotisnigrita and North African catfish Clarias gariepinus on the other hand were observed to have an omnivorous feeding pattern with plant parts, insect parts, detritus, crustaceans, snails, worms, fish parts, insects larvae, sand/mud, and algae dominating their diet. Many of the omnivores encountered in this study have good potential as future aquaculture candidate hence the need to further study their biology and their performance under captivity.

This research work presents an experimental evaluation of the effect of sustained loading on reinforced concrete beams made with 50% replacement of natural coarse aggregates with aggregates from old concrete. A total of 9 RC beams were cast, 6 with natural coarse aggregates and 3 with recycled concrete aggregates. All beams were cured for 28 days in standard fashion. Among the first batch, 3 beams were used to test under short term loading till failure. An application of 50% of short-term loading followed on all beams assembled on purpose made frames. All beams were monitored for deflection, strain, and cracking. Both deflection and strain remained within limits. Crack monitoring revealed maximum crack width 0.5 mm. After six months of sustained load, beams were removed from the frames and tested in universal load testing machine with central point load till failure. The load-deflection pattern of all beams was observed to be almost similar and 22.12% higher in recycled concrete bea...

Farklı yemlerle beslenen avrupa yılanbalığı (Anguilla anguilla L.)'nda bazı büyüme parametreleri. Bu çalışmanın amacı, balıkhane artıkları (BA), tavuk kesimhanesinin bazı artıkları (TA), kuru karma alabalık yemi (YY), balıkhane artıkları ile kuru karma alabalık yemi karışımı (BA+YY) ve tavuk kesimhanesinin bazı artıkları ile kuru karma alabalık yemi karışımının (TA+YY) Avrupa yılanbalığının bazı büyüme parametreleri üzerine etkisinin belirlenmesidir. Başlangıç ortalama ağırlığı 99,07±2,96g olan yılanbalıkları 80 günlük deneme süresi sonunda en iyi TA+YY yemi ile büyüme kaydetmiştir (128,56±1,75g). Bu grubun spesifik büyüme oranı % 0,33±0,02, yem değerlendirme oranı ise 8,82±0,29 olarak bulunmuştur. Bu grubu TA, BA+YY, YY, BA grupları izlemiştir. Canlı ağırlık ortalamaları gruplar arasında istatistiki olarak farklılık göstermiştir. BA grubunun sonuç ağırlık ortalaması taze balık eti verilen yılanbalıkları için bildirilen değerler arasındadır. Gruplarda görülen ölüm oranları %7,40±4,90 ile %16,66±3,21 arasında değişim göstermiştir.

Farklı yemlerle beslenen avrupa yılanbalığı (Anguilla anguilla L.)'nda bazı büyüme parametreleri. Bu çalışmanın amacı, balıkhane artıkları (BA), tavuk kesimhanesinin bazı artıkları (TA), kuru karma alabalık yemi (YY), balıkhane artıkları ile kuru karma alabalık yemi karışımı (BA+YY) ve tavuk kesimhanesinin bazı artıkları ile kuru karma alabalık yemi karışımının (TA+YY) Avrupa yılanbalığının bazı büyüme parametreleri üzerine etkisinin belirlenmesidir. Başlangıç ortalama ağırlığı 99,07±2,96g olan yılanbalıkları 80 günlük deneme süresi sonunda en iyi TA+YY yemi ile büyüme kaydetmiştir (128,56±1,75g). Bu grubun spesifik büyüme oranı % 0,33±0,02, yem değerlendirme oranı ise 8,82±0,29 olarak bulunmuştur. Bu grubu TA, BA+YY, YY, BA grupları izlemiştir. Canlı ağırlık ortalamaları gruplar arasında istatistiki olarak farklılık göstermiştir. BA grubunun sonuç ağırlık ortalaması taze balık eti verilen yılanbalıkları için bildirilen değerler arasındadır. Gruplarda görülen ölüm oranları %7,40±4,90 ile %16,66±3,21 arasında değişim göstermiştir.

The study investigated morphological variations among samples of Macrobrachium vollenhovenii captured from Taylor Creek, Calabar Estuary and New Calabar River in the Niger Delta Region. A total of 76 individuals were caught using cone-shaped bamboo basket traps. The prawns were identified and 18 morphological characters were measured on each individual. All the data generated were analyzed using the PAST3 and JASP statistical software. The results of the study indicated that the morphometric measurements among the populations of M.

Background: Mature male parr (MMP) represent an important alternative life-history strategy in Atlantic salmon populations. Previous studies indicate that the maturation size threshold for male parr varies among wild populations and is influenced by individual growth, environmental conditions, and genetics. More than ten generations of breeding have resulted in domesticated salmon displaying many genetic differences to wild salmon, including greatly increased growth rates. This may have resulted in domesticated fish with the potential to outgrow the size threshold for early maturation, or evolution of the size threshold of the trait itself. To investigate this, we performed a common-garden experiment under farming conditions using 4680 salmon from 39 families representing four wild, two wild-domesticated hybrid, and two domesticated strains. Results: Domesticated salmon outgrew wild salmon 2-5-fold, and hybrids displayed intermediate growth. Overall, the numbers of MMP varied greatly among families and strains: averaging 4-12% in domesticated, 18-25% in hybrid, and 43-74% in the wild populations. However, when the influence of growth was accounted for, by dividing fish into lower and upper size modes, no difference in the incidence of MMP was detected among domesticated and wild strains in either size mode. In the lower size mode, hybrids displayed significantly lower incidences of mature males than their wild parental strains. No consistent differences in the body size of MMP, connected to domestication, was detected. Conclusions: Our data demonstrate: 1-no evidence for the evolution of the size threshold for MMP in domesticated salmon, 2-the vastly lower incidence of MMP in domesticated strains under aquaculture conditions is primarily due to their genetically increased growth rate causing them to outgrow the size threshold for early maturation, 3-the incidence of MMP is likely to overlap among domesticated and wild salmon in the natural habitat where they typically display overlapping growth, although hybrid offspring may display lower incidences of mature male parr. These results have implications for wild salmon populations that are exposed to introgression from domesticated escapees.

Aim. Chronic autoimmune thyroiditis and type 1 diabetes mellitus are organ-specific autoimmune diseases. There is large evidence that autoimmunity against the thyroid gland in patients with type 1 diabetes mellitus is increased, but little is known about anti-islet cell autoimmune status in patients with chronic autoimmune thyroiditis. We evaluated the concentration of antibodies against glutamic acid decarboxylase (GAD) which are widely used as a diagnostic and predictive tool for type 1 diabetes mellitus, in school-aged Georgian children with chronic autoimmune thyroiditis.Methods. The frequency of anti-GAD antibodies was measured in Georgian school-aged children with chronic autoimmune thyroiditis and compared to healthy age and sex matched controls.Results. Of the 41 patients with chronic autoimmune thyroiditis 4 (9.8%) were positive for GAD antibodies. The frequency of GAD positivity in the chronic autoimmune thyroiditis group was significantly higher than in the control subjec...

In this study, seasonal change in feeding habit, health status and breeding season of Indian mackerel (Rastrelliger kanagurta, Cuvier) have been observed in the coastal water of West Bengal. Gut contents were analyzed to check its feeding habit. Exponential value, condition factor and breeding habits were also examined. Study on feeding habit establishes Indian mackerel to be a selective plankton feeder. During pre-monsoon season; diatoms, copepods, rotifers and green algae were dominant, while blue green algae (BGA) and dinoflagellates had highest percentage of occurrence during the monsoon season. Feeding habit study of Indian mackerel in long term basis may further help in determining its trophic level position and locating its probable fishing ground.

The quality of reassuring opinions on health risks due to EMF p. 6.3. Even some international science journals are involved in conflicts of interest p. 6.4. Methods used to confound epidemiological results and compromise their consequences p. 7. RECENT PRECAUTIONARY POSITIONS ON HEALTH RISKS OF EMF EXPOSURE p. 8. HOW TO PROMOTE PROTECTION AGAINST THE HEALTH EFFECTS OF EXPOSURE TO EMF p. 9 . CONCLUSIONS p. 10. REFERENCES p.

The canonical Redfield C:N:P ratio for algal biomass is often not achieved in inland waters due to higher C and N content and more variability when compared to the oceans. This has been attributed to much lower residence times and higher contributions of the watershed to the total organic matter pool of continental ecosystems. In this study we examined the effect of water residence times in low latitude lakes (in a gradient from humid to a semi-arid region) on seston elemental ratios in different size fractions. We used lake water specific conductivity as a proxy for residence time in a region of Eastern Brazil where there is a strong precipitation gradient. The C:P ratios decreased in the seston and bacterial size-fractions and increased in the dissolved fraction with increasing water retention time, suggesting uptake of N and P from the dissolved pool. Bacterial abundance, production and respiration increased in response to increased residence time and intracellular nutrient availability in agreement with the growth rate hypothesis. Our results reinforce the role of microorganisms in shaping the chemical environment in aquatic systems particularly at long water residence times and highlights the importance of this factor in influencing ecological stoichiometry in all aquatic ecosystems.

Reservoirs is one of the great sources of fish and contribute significantly to the fish consumed. However, catches from different water bodies have declined over the past few decades partly due to various illegal fishing activities. The study was conducted on Kafin gana reservoir in Birnin Kudu, Jigawa in 2018 to assess fish species composition and abundance in order to provide technical information for sustainable exploitation of fish. Biodiversity indices (Shannon weiner index and Simpson , index of diversity) indicate that the reservoir is diverse. A total of fifteen(15) fish species representing nine(9) families were identified under families Mormyridae,Claridae, Cichlidae, Schilbedae, Mochokidae,Cyprinidae,Bagridae, Protopteridae, and Palaemonoidae during the dry an drainy seasons. The family Cichlidae had the highest representation in terms of species number. Mormyridae hadthe highest relative abundance of (45.89%) during the rainy season and Palaemonoidae had highest relative abundance of (44.94%)during the dry season. Palaemonoidae and Protopteridae were only found during the dry and rainy season respectively. The overall diversity indices of this reservoir fall between moderate with Shannon weiner index of 1.761 to a higher with Simpso's index of 0.803. The Simpso's index indicates that there is 80% chance of randomly picking 2 families that are different. The results of the study revealed the need for management interventions to manage the Kafin gana reservoir.

The issue on the overfishing of parrotfishes, locally known as “molmol” (subfamily Scarinae under family Labridae), in the coastal waters of Bohol province in Central Visayas has been raised by the Provincial Agricultural and Fishery Council (PAFC) of Bohol through Resolution No. 1 series of 2018 that pushes for the implementation of “open and closed fishing season” of all parrotfishes in the entire province. In any management intervention, baseline assessment of the stocks in question should be done as a significant basis for appropriate measures to be taken, thus this study. In Bohol, apart from the economic value, they carry essential functions in maintaining the ecological balance in the reef ecosystem. Parrotfishes are considered economically important as preferred fish among locals and tourists. The stock assessment of parrotfishes in Danajon Bank in the Bohol Sea and Cebu Strait was conducted by the National Stock Assessment Program (NSAP) Region 7 from 2015 to 2018 in 16 coa...

The issue on the overfishing of parrotfishes, locally known as "molmol" (subfamily Scarinae under family Labridae), in the coastal waters of Bohol province in Central Visayas has been raised by the Provincial Agricultural and Fishery Council (PAFC) of Bohol through Resolution No. 1 series of 2018 that pushes for the implementation of "open and closed fishing season" of all parrotfishes in the entire province. In any management intervention, baseline assessment of the stocks in question should be done as a significant basis for appropriate measures to be taken, thus this study. In Bohol, apart from the economic value, they carry essential functions in maintaining the ecological balance in the reef ecosystem. Parrotfishes are considered economically important as preferred fish among locals and tourists.

detected in rural sampling locations. Contamination profiles of PCBs, PBDEs and OCPs differed also among the sampling locations, which may be due to local usage and contamination sources. The higher variance among sampling locations for the PCBs and OCPs, suggests that local contamination sources are more important for the PCBs and OCPs compared to the PBDEs. To our knowledge, this is the first study in which bird eggs were used as a monitoring tool for OHPs on such a large geographical scale.

Juata waters of Tarakan city are waters have marine biological resources, one of which is fish nomei. Fish Nomei (Harpodon nehereus) is a species of fish that have morphological structures meat mushy and have a fairly high economic value in the form of dried processed fish products. The aim of this riset is to know the aspects of growth and age structure of fish nomei (Harpodon nehereus) from catches of fishermen in waters juata of Tarakan City. This research used a descriptive exploratory study using a case study approach. The scope of the study focused on variables population growth of absolute approaches model of von Bertalanffy. Data collection techniques, using survey research design. Sampling technique using purposive sampling. Time sampling was conducted during the period of low tide . Nomei sampling fish sampling done 6 times with 4 different fishermen. Each sample of 30 fishermen taken nomei fish. The results, growth fish of nomei male has a maximum length of growth to reach the age of 33.847 cm for 206 days. Model growth of Von Bertalanffy that Lt = 33.847 ( 1-2.71828 -0.0176(1.7928+t) ), with value r = 0.9 and the number of samples (n) as much as 481 tails. Growth fish of nomei female have long growth with a maximum of 35.743 cm reached the age for 603 days. Growth fish of nomei females at the age of 290 days has reached a length of about 35.068 cm. Growth of model Von Bertalanffy that Lt = 35.743 ( 1 -2.71828 -0.0136 (t+1.9025) ) , with value r = 0.99 and the number of samples ( n ) as much as 239 tails.

A 56 day study was carried out to evaluate the growth performance and nutrient utilization of Nile Tilapia fed diets containing housefly maggot meal (magmeal). Three isoenergetic diets respectively containing 31.20, 34.0 and 36.10% crude protein were formulated. Fishmeal was replaced partially with magmeal. Results of the study showed a good overall growth performances and status of experimental fish. Standard growth rate was between 2.58 -3.08; food conversion ratio ranged from 1.12 to 1.45; Protein efficiency ratio was between 2.21-2.47, while hepatosomatic Index and condition factor were ranged between 3.08-3.14; and 2.47-2.89, respectively. Fish survival was 100%. These recommend the suitability of magmeal in diets for Nile tilapia fingerling. However, the apparent crude protein digestibility of diet 3 (65.71%) containing highest magmeal dietary inclusion level, decreased significantly compared to diet 1 and 2 (76.26%, 77.04%). This may be due to the effect of elevated ash concentration of magmeal used in the diet formulation.

Fish species abundance, seasonal variation and condition factor (k) was assessed in this study between October 2012 and September 2013. Samples collected from Erinle reservoir were identified and sorted out into species, the morphometric parameters of each sample were measured using a measuring board graduated in cm and weighed using a Mettler balance (P 1210 model). Fulton’s condition factor (k) was calculated using the equation K=100W/L. Fish species identified were twelve: Alestes macrolepidotus , Chromidotilapia guntheri , Oreochromis niloticus , Sarotherodon galilaeus , Tilapia mariae , Tilapia zillii , Clarias gariepinus , Chrysichthys auratus , Hepsetus odoe , Mormyrus rume , Marcusenius senegalensis and Schilbe mystus . The species belong to seven families from a total of 561 fish samples with varying degree of abundance. S. galilaeus had the highest abundance of 55.08% of the total samples collected while C. gariepinus had the lowest abundance of 0.18% as only one sample wa...