Comparison of growth performance of live feed microalgae and rotifer (Brachionus sp.) under different feeding medium in outdoor culture condition

Live feed is the basic food source and nutrient security for successful seed production of any commercially important aquaculture species of fishes, mollusks and crustaceans. Both plant and animal originated aquatic microscopic organisms are generally termed as live food. They are the basic food items in early stages (larval stage) of life cycle due to small sizes, easy digestibility and enriched in nutrients. The Nannochloropsis sp.; Nannochlorum sp. and Tetraselmis sp. are rich with relatively high content of essential fatty acids in comparison to other marine algae. Likelihood, the rotifer Brachionus sp. is ideal feed item for brackishwater finfish and mud crab larvae rearing due to its special features like rapid reproduction, slow movement, suitable size and easy digestion by the newly hatched larvae. The present study is the report on comparison of growth performance of live feed (microalgae and rotifer) in outdoor culture condition. The study was conducted at the hatchery complex of Bangladesh Fisheries Research Institute, Brackishwater Station, Paikgacha, Khulna. In outdoor culture condition the growth pattern obtained for three microalgae were Tetraselmis sp.> Nannochlorum sp.> Nannochloropsis sp. Highest average growth 6.87×106±1.97×106, 6.91×106±1.69×106 and 6.23×106±1.53×106 was observed for Nannochloropsis sp., Nannochlorum sp. and Tetraselmis sp. respectively in trial 3. Average growth of rotifer (Brachionus sp.) found highest 189±18.10 ind./ml at combined media of yeast and microalgae and lowest growth 119.67±17.60 ind./ml noticed with baker's yeast media. Nannochloropsis sp. contains more energy among all microalgae but Tetraselmis sp. carry highest level of protein. The highest level of protein 56.3±0.18% found in rotifer enriched with microalgae+fish oil and lowest protein content noticed with microalgae enrichment media. So, research finding suggests that, treatment T3 would be the best recommendations for rotifer culture.

PERTUMBUHAN DAN PRODUKTIVITAS Oedogonium sp. PADA INTENSITAS CAHAYA YANG BERBEDA

Oedogonium sp. is important, not only from an academic standpoint but also has great ecological significance, especially in limnology. This study examines the growth and productivity of Oedogonium sp. under different light intensity in laboratory scale. The main research includes Oedogonium sp. culture, measurement of growth (doubling time (DT) and relative growth rate (RGR)), measurement of primary productivity, and the effect of light measurement on cells through observation of histological preparations. The results showed that Oedogonium sp. on indoor culture showed negative growth (RGR of -0.054), whereas in semi-outdoor culture showed positive growth (RGR 0.046 - 0.47 g / day and DT for 14.72 - 15.09 days. Primary productivity and respiration in 1000 lux lighting cultures showed greater value than cultures in 650 lux lighting. The length of Oedogonium sp. ranged from 18.68 - 34.47 µm in dark light, 51.33 - 95.00 µm in moderate light, and 48.83 - 70.75 µm in bright light. This study showed that in indoor culture, the availability of light, temperature, pH and DO significantly affect the growth of Oedogonium sp., whereas in semi-outdoor culture, temperature, pH and DO factors was not limiting factors. The difference of light intensity influenced the growth and productivity of Oedogonium sp.

“The Stories That Will Make a Difference Aren’t the Easy Ones”: Outdoor Recreation, the Wilderness Ideal, and Complicating Settler Mobility

In this autoethnography, I read my history of and connection to outdoor culture, with an eye toward interrogating my complicity in historical and ongoing settler-colonial violence that has rendered my love of “the mountains” both possible and ostensibly unproblematic. In so doing, I unsettle (my) understandings of the connections between land, embodiment, masculinities, and able-bodiedness, exploring how settler attachment to the mountains is predicated on and serves to perpetuate, a(n ongoing) history of land dispossession. I also, however, consider a “different temporal horizon” through a discussion of settler futurity as it relates to outdoor recreation, complicating settler mobility in the process.