scholarly journals Intraspecific variation in the growth and survival of juvenile fish exposed to E ucalyptus leachate

2013 ◽  
Vol 3 (11) ◽  
pp. 3855-3867 ◽  
Author(s):  
John R. Morrongiello ◽  
Nicholas R. Bond ◽  
David A. Crook ◽  
Bob B. M. Wong
Keyword(s):  
Intraspecific Variation ◽  
Juvenile Fish ◽  
Growth And Survival

scholarly journals Light and nutrient supply mediate intraspecific variation in the nutrient stoichiometry of juvenile fish

Ecosphere ◽  
2016 ◽  
Vol 7 (10) ◽  
pp. e01452 ◽  
Author(s):  
Kelsea N. Downs ◽  
Nicole M. Hayes ◽  
Amber M. Rock ◽  
Michael J. Vanni ◽  
María J. González
Keyword(s):  
Intraspecific Variation ◽  
Juvenile Fish ◽  
Nutrient Supply ◽  
Nutrient Stoichiometry

scholarly journals Hormones as adaptive control systems in juvenile fish

2019 ◽  
Author(s):  
Jacqueline Weidner ◽  
Camilla Håkonsrud Jensen ◽  
Jarl Giske ◽  
Sigrunn Eliassen ◽  
Christian Jørgensen
Keyword(s):  
Food Availability ◽  
Hormonal Regulation ◽  
Juvenile Fish ◽  
Optimal Strategies ◽  
Evolutionary Optimization ◽  
Hormonal Control ◽  
Fish Growth ◽  
Growth And Survival ◽  
Hormone Levels ◽  
Regulation Of Growth

AbstractGrowth is an important theme in many biological disciplines. Physiologists often relate growth rates to hormonal control of essential processes. Ecologists often study growth as function of gradients or combinations of environmental factors. Fewer studies have investigated the combined effects of environmental and hormonal control on growth. Here, we present an evolutionary optimization model of fish growth that combines internal regulation of growth by hormone levels with the external influence of food availability and predation risk. Hormones are represented by growth hormone, thyroid hormone and orexin functions. By studying a range from poor to rich environments, we find that the level of food availability in the environment results in different evolutionarily optimal strategies of hormone levels. With more food available, higher levels of hormones are optimal, resulting in higher food uptake and growth. By using this fitness-based approach we also find a consequence of evolutionary optimization of survival on optimal hormone use. Where foraging is risky, aerobic scope can be used strategically to increase the chance of escaping from predators. By comparing model results to empirical observations, many mechanisms can be recognized, for instance a change in pace-of-life due to resource availability, and reduced emphasis on reserves in more stable environments.Summary statementWe combine physiological, environmental and evolutionary aspects of fish growth in a state-dependent model where the optimal regulation of growth and survival is achieved through hormonal regulation of behaviour.

Hormonal adjustments to future expectations impact growth and survival in juvenile fish

Oikos ◽  
2020 ◽  
Vol 130 (1) ◽  
pp. 41-51
Author(s):  
Camilla Håkonsrud Jensen ◽  
Jacqueline Weidner ◽  
Jarl Giske ◽  
Sergey Budaev ◽  
Christian Jørgensen ◽  
...  
Keyword(s):  
Juvenile Fish ◽  
Future Expectations ◽  
Growth And Survival

Impact of the Great East Japan Earthquake tsunami on growth and survival of Pacific cod (Gadus macrocephalus)

2015 ◽  
Vol 72 (11) ◽  
pp. 1629-1638 ◽  
Author(s):  
Yoji Narimatsu ◽  
Shigeho Kakehi ◽  
Shin-ichi Ito ◽  
Yuji Okazaki ◽  
Ryo Inagawa ◽  
...  
Keyword(s):  
Body Size ◽  
Juvenile Fish ◽  
Pacific Cod ◽  
Physical Damage ◽  
Lower Growth ◽  
Growth And Survival ◽  
The North ◽  
Pacific Cod Gadus Macrocephalus ◽  
Gadus Macrocephalus ◽  
Using Data

A massive tsunami hit the north Pacific coast of Japan on 11 March 2011. We evaluated the effects of the tsunami on the distribution, growth, and survival of young Pacific cod (Gadus macrocephalus) using data from benthic trawl surveys and otolith microstructure analysis. The distribution of Pacific cod juveniles differed between 2011 and 2008–2010. The 2011 year class was smaller in body size than those in 2008–2010. The majority of 2011 year-class juveniles was captured in deeper areas at a smaller body size, whereas those of previous year classes were primarily distributed in shallower water. The peak hatch of the 2011 year-class juveniles was from early to late February, which was several days later than those of the 2008 and 2010 year classes. The 2011 year class grew at the same rate as those from 2008 and 2010 until the day of the tsunami, but had a lower growth rate during the 30 days after the tsunami, resulting in a decrease in fish size at settlement. Growth of the 2011 year class was also inferior soon after the day of the tsunami in almost all groups divided by the hatching period. Growth of juveniles captured in shallower water following the tsunami in 2011 tended to be slower than that of juveniles captured in deeper water. Our results suggest that the tsunami caused a decrease in growth rates for approximately 30 days and a change in the distribution of juvenile fish relative to prior years. The change in distribution was primarily the result of mortality in shallow water caused by physical damage and (or) subsequent decreased growth. Considering these results and the finding that the recruitment level and the recruits per spawning in the 2011 year class were low, the tsunami may have affected the determination of the recruitment level.

scholarly journals Simulated eutrophication and browning alters zooplankton nutritional quality and determines juvenile fish growth and survival

2018 ◽  
Vol 8 (5) ◽  
pp. 2671-2687 ◽  
Author(s):  
Sami Johan Taipale ◽  
Kimmo Kalevi Kahilainen ◽  
Gordon William Holtgrieve ◽  
Elina Talvikki Peltomaa
Keyword(s):  
Nutritional Quality ◽  
Juvenile Fish ◽  
Fish Growth ◽  
Growth And Survival

PREFERENSI PENEMPELAN, PERTUMBUHAN, DAN SINTASAN LARVA TERIPANG PASIR, Holothuria scabra PADA SUBSTRAT LAMUN YANG BERBEDA

2017 ◽  
Vol 11 (3) ◽  
pp. 249
Author(s):  
Lisa Fajar Indriana ◽  
Yuli Afrianti ◽  
Sitti Hilyana ◽  
Muhammad Firdaus Firdaus
Keyword(s):  
Survival Rate ◽  
Economic Value ◽  
Growth And Survival ◽  
Holothuria Scabra ◽  
Enhalus Acoroides ◽  
Randomized Design ◽  
Settlement Substrate ◽  
Cymodocea Rotundata ◽  
Syringodium Isoetifolium ◽  
Cymodocea Serrulata

Teripang pasir, Holothuria scabra merupakan komoditas hasil laut yang bernilai ekonomis tinggi. Penangkapan berlebihan stok di alam mendorong berkembangnya kegiatan budidaya. Penempelan merupakan fase kritis pada larva teripang karena terjadi peralihan sifat planktonis ke bentik yang memerlukan substrat. Penelitian ini bertujuan untuk mengetahui preferensi penempelan, pertumbuhan, dan sintasan larva H. scabra fase penempelan pada substrat lamun yang berbeda. Penelitian menggunakan metode rancangan acak lengkap dengan perlakuan empat jenis daun lamun berbeda dan lima ulangan. Perlakuan terdiri atas Enhalus acoroides (L-1), Syringodium isoetifolium (L-2), Cymodocea serrulata (L-3), dan Cymodocea rotundata (L-4). Jumlah awal larva sebanyak 1.000 individu dan substrat dirangkai dengan luasan yang sama sebesar 12 cm x 17 cm untuk setiap unit penelitian. Hasil penelitian menunjukkan jenis lamun yang digunakan sebagai substrat berpengaruh secara nyata terhadap preferensi penempelan dan sintasan larva teripang pasir, namun tidak berpengaruh terhadap pertumbuhan. E. acoroides menunjukkan hasil terbaik dengan preferensi penempelan 0,26 ind. cm-2 dan sintasan 10,66%; sehingga layak digunakan sebagai substrat penempelan dalam pembenihan teripang pasir, H. scabra.Holothuria scabra larvae on different seagrass substrates. By: Lisa Fajar Indriana, Yuli Afrianti, Sitti Hilyana, and Muhammad FirdausSandfish Holothuria scabra is marine commodities with a high economic value. Overfishing of natural stocks has compelled an interest to begin aquaculture practice. Settlement is a critical phase for the planktonic larvae as they will transform to benthic form in the presence of substrate. This study aims to evaluate the settlement preferences, growth, and survival rate of H. scabra larvae settled on different seagrass leaves. The research was conducted using the Completely randomized design with four different species of seagrass leaves and five replications. The treatments consist of Enhalus acoroides (L-1), Syringodium isoetifolium (L-2), Cymodocea serrulata (L-3), and Cymodocea rotundata (L-4). Initial number of larvae was 1,000 individuals and the substrate was set with same widthof 12 cm x 17 cm for each unit. Results of the experiment indicated that settlement preference and survival rate of H. scabra larvae was significantly affected by seagrass used as substrate while no significantly differences was observed for growth of larvae. E. acoroides showed the best result with 0.26 ind. cm-2 settelement preference and 10.66% survival rate, so that suitable to be used as settlement substrate in H. scabra hatchery.

Consumer Awareness, Consumer Protection, Service Quality and Loyalty: The Case of Long-term Insurance Consumers in Namibia

2019 ◽  
Vol 118 (8) ◽  
pp. 172-189
Author(s):  
Magreth B Tjizumaue ◽  
Krishna Govender
Keyword(s):  
Service Quality ◽  
Consumer Protection ◽  
Structural Equation ◽  
Insurance Industry ◽  
Business Practices ◽  
Consumer Awareness ◽  
Growth And Survival ◽  
Term Insurance ◽  
Protection Legislation

Due to the absence of appropriate Consumer Protection legislation in Namibia, there seems to be a lack of consumer protection, which may result in consumers being exploited. Since the literature reveals that Consumer Awareness, Consumer Protection, Service Quality and Customer Satisfaction influence Customer Loyalty, the aforementioned relationship was explored among consumers of long-term insurance products in Namibia. The researcher embedded the study in the Services Marketing and User’s Satisfaction/Dissatisfaction theory and developed a framework for creating a more aware consumer and thus contribute to the growth and survival of the long-term insurance industry in Namibia.  A survey was conducted using a questionnaire, among a judgmental sample of 407 long-term insurance consumers in Namibia and Structural Equation Modelling was used to analyse (eight) hypothesized relationships among the research constructs alluded to in the title of this study. In summary, it was ascertained that if the customers are fully aware (have sufficient knowledge of the products and their consumer rights), they will feel protected against unfair business practices. Furthermore, if they perceive having received quality services, they are more likely to be satisfied with the service provider and will therefore, remain loyal.

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