A response-surface approach to the combined effects of temperature and salinity on the larval development of Adula californiensis (Pelecypoda: Mytilidae). II. Long-term Larval survival and growth in relation to respiration

1973 ◽  
Vol 22 (4) ◽  
pp. 295-305 ◽  
Author(s):  
R. G. Lough ◽  
J. J. Gonor
2020 ◽  
Vol 8 (3) ◽  
pp. 213 ◽  
Author(s):  
Il-Kweun Oh ◽  
Seung-Woo Lee

Deiratonotus japonicus (D. japonicus) inhabits isolated locations and upstream brackish waters from Kanagawa Prefecture to Okinawa Prefecture in Japan. This species faces the threat of extinction because of changing habitat conditions. Our previous studies have shown that its complete larval development from hatching to metamorphosis consists of five zoeal stages and one megalopal stage. In this study, the effect of temperature on the survival and growth of larval development in D. japonicus under controlled laboratory conditions of 13, 18, 23, 24, 25, and 26 °C was investigated by rearing larvae (30 PSU; 12:12 h light/dark cycle; fed a diet of Brachionus plicatilis rotundiformis and Artemia sp. nauplii). The survival rates and developmental periods were measured for each larval stage. The highest survival rates were obtained at 18–24 °C. Metamorphosis to megalopa occurred at 23–25 °C. There were rapid and synchronous developments at 25–26 °C but delayed and extended developments at 13 °C. The molting period decreased with increasing temperature. With decreasing temperature, the beginning of the development and duration of molting was prolonged. In addition, there were very low survival rates at 13 °C and 26 °C in all zoeal stages. Our results indicate that the early larval stages of D. japonicus are well adapted to 18–24 °C, the range observed in the estuarine marine environment of the Kita River during the breeding season. Optimum larval survival and growth were obtained at 23 °C. Temperature significantly affected the survival rate, developmental period, and molting of the larvae. The relationship between the cumulative periods of development from hatching through individual larval stages (y) and temperatures (T) was described as a power function (y = a × Tb).


Author(s):  
Md. Shamim Parvez ◽  
M. Aminur Rahman ◽  
Md. Jahidul Hasan ◽  
Md. Habibur Rahman ◽  
Nawshin Farjana ◽  
...  

The combined effects of temperature and salinity on percent hatching, normal larval rate at hatching, and survival of fasting larvae after hatching (survival activity index; SAI) of the commercial species of collector sea urchin, Tripneustes gratilla were investigated in a captive laboratory condition. The study was conducted by setting different levels of temperatures (24°C to 36°C) and salinities (38‰ to 23‰). Within the range of temperature from 24 to 36°C and at 32‰ salinity, hatching and normal larval rates, and SAI values were highest at 24 and 27°C. The highest hatching and normal larval rates were found at 35 and 38‰ within the salinity range of 23-38‰; however, SAI value was the highest at 26‰. The results of the experiments in each level of temperature (24, 27 and 30°C) with each salinity (32, 35 and 38‰) indicated interactive effects of temperature and salinity, and within the experimental protocols of 24°C at 38‰ gave an optimal combination for highest hatching and survival of T. gratilla. The findings obtained from the present research would not only be immensely helpful towards the understanding of the suitable temperature-salinity interactions but also facilitate the development of captive breeding, larval raising and mass seed production of this high-valued sea urchin for commercial aquaculture.


2020 ◽  
Vol 71 (3) ◽  
pp. 384 ◽  
Author(s):  
Rafael Rogério Rosa ◽  
Jislaine Cristina Silva ◽  
Andréa Bialetzki

Freshwater fish reproduce annually in environments that provide favourable conditions for spawning and larval survival and growth. Thus, the aims of this study were to use long-term larval density data to evaluate the temporal distribution of the dourado Salminus brasiliensis, its habitat use for larval development and the effects of environmental variables on reproduction. S. brasiliensis larvae were mainly recorded in October and January in the Ivinheima River, and higher densities of larvae, primarily in the preflexion and flexion stages, were captured in the river and backwater biotopes. Water level, dissolved oxygen and temperature were the primary variables affecting the density of larvae, and this species can migrate over 200km to reproduce in the Ivinheima River and its tributaries. Therefore, S. brasiliensis is reproducing annually, indicating favourable local conditions for migration and spawning, and exhibits differential use of biotopes for reproduction, including rivers and backwaters (spawning) and lagoons (refuge and growth). Therefore, considering that the dourado is a key species for conservation, ensuring its reproductive success means maintaining a balanced ecological structure.


Author(s):  
José Paula ◽  
Ricardo Nogueira Mendes ◽  
Sabrina Paci ◽  
Pat McLaughlin ◽  
Francesca Gherardi ◽  
...  

2017 ◽  
Vol 115 (1-2) ◽  
pp. 201-210 ◽  
Author(s):  
Perrine Gamain ◽  
Patrice Gonzalez ◽  
Jérôme Cachot ◽  
Christelle Clérandeau ◽  
Nicolas Mazzella ◽  
...  

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