Hawaiian Red Shrimp...my turn.

frugalfish · Post by **frugalfish** » Fri Mar 03, 2006 8:54 am

I'm not sure if it's the salinity or not that has cause my shrimp to have poor/low reproduction. I have had them for almost a year and up until now only have had a few berried females and those all dropped their eggs. Before lowering the salinity to where it is now I had the salinity at 1.012-1.014 and at that concentration no reproduction resulted at all. Although salinity could be a factor, it may also be a case of this group maturing enough or finally finding the conditions of their environment are to their liking. What ever the case may be I am disappointed that the two females that were recently carrying seem to have only produced four young, but at the same time I'm very happy to finally have reached another level with these shrimp. Perhaps this is just a nice beginning to things to come.

frugalfish · Post by **frugalfish** » Thu Mar 09, 2006 7:57 pm

It's been a little while, but the larva are finally turning into little shrimp. Noticed today that they are now able to stand on the sides of the tank. Haven't seen any walking, but definitely standing on legs. So far they land on the glass and after some time float for a bit and then land again and repeat this over and over.

There are also now a total of three ovigerous females.

Daudin · Post by **Daudin** » Sat Mar 11, 2006 6:32 am

Hi all,

maybe Opae ula needs salinity fluctuations for regular and successful reproduction (tide influence ?). Stable salinity (whether high or now) is not good. Or Opae ula needs salinity gradient in its environment, where animals find correct salinity to fit to specific ontogenetic stage or fyziological process (shed, reproduction, larval development etc.).

YuccaPatrol · Post by **YuccaPatrol** » Wed Mar 22, 2006 5:24 am

I completely forgot about these shrimps until today when I found this thread while searching for Cherry shrimp info.

A few years ago, my parents were in Hawaii and sent me a small little plastic cube with some of these shrimp. They were sold as a self-contained ecosystem, although we know that is really not an appropriate way for them to live. Unfortunately, the cube leaked during shipment and the shrimp only had a few cubic inches of water to live in.

Now that I know more about them, I think it is a terrible way to sell such wonderful creatures to tourists, but I did enjoy the shrimp for the time I had them.

Fortunately, I will be returing to Hawaii in a couple months and plan to bring back a nice population of them for my tanks. This time I will make it right for my little shrimps.

Shrimpmania · Post by **Shrimpmania** » Thu Mar 23, 2006 9:38 am

CONGRATS!! NICE TANK anyway

frugalfish · Post by **frugalfish** » Tue Mar 28, 2006 10:38 am

Wow! Time sure is flying by this year. Just spotted a free floating larva and had to recheck this thread to see when I had last seen a pregnant female and sure enough it's been around a month. Salinity levels in the tank are now around 1.006.

Post by **Mustafa** » Tue Mar 28, 2006 12:04 pm

Congrats!

Also keep an eye out for some tiny juveniles from your last batch. Just when you think your larvae have all died you might start seeing some juveniles running around. Look in the dark corners of the tank. They like to hide from bright light.

frugalfish · Post by **frugalfish** » Tue Mar 28, 2006 3:13 pm

Yep! I've been seeing the little shrimp from time to time including today. They are usually swimming across the tank when I spot them. I think I may have four total. Not sure which female is releasing the new larva, but as I was looking in the tank again I spied a rather ovigerous female moving about in the dark of the rocks. Next post I'll report on how many new larva appear.

Daudin · Post by **Daudin** » Thu Mar 30, 2006 1:37 pm

Some potentially interesting extracts from science papers about H.rubra and their habitat.

Bailey-Brock JH, R.E. Brock. 1993. Aspects of the feeding, reproduction and sensory biology of the Hawaiian anchialine shrimp, Halocaridina rubra Holthuis (Atyidae). Pac. Sci. 47:338-355. :

„Salinity of the pools varies from less than 2 ‰ to 33,5 ‰ or more, depending upon proximity to the ocean and groundwater source that percolate through the lava from adjacent land and mountain slopes. The Ewa, Ohau, pools are 4 ‰ and West Hawaii (Kona coast) pools are usually 6 – 15 ‰, except for Lua o Palahemo at South point, Hawai, where salinity is 20 ‰ at the surface and 34‰ at 20 m."

„In this anchialinne pool habitat these shrimp occupy two physically different habitats, the epigeal or well-lighted shallow pools and the hypogeal habitat of dark crevices in th water table below pools.“

„The typical benthic assemblage that covers the bottom of many shrimp-inhabitaed pools is composed of cyanobacteria, associated filamentous algae, and diatoms, forming an orange crust.“…“Shrimp feed by ´brushing´ this crust with the cheliped setae of the first two pairs of pereiopods.“

„Information about the reproduction of these shrimp is limited to populations maintained in the laboratory, becouse berried shrimp have not been found in the pools.“

„These shrimp exhibit two feeding methods in the anchialine pool habitat. The first has been described as plucking (Maciolek 1983), grasping (Wong 1975), scraping (Bailey-Brock et al. 1991), and brushing food from the substratum“…“The second mode has been described as filter feeding (Maciolek 1983) and filtration (Wong 1975)“…“The first method is most commonly observed when the shrimp are on a substrate; the second is seen only sometimes when the shrimp are in phytoplankton-rich pools and they are swimming or otherwise off the bottom of the pool.“

„Locomotory activity includes swimming across the substrata, swimming up toward the pool surface and returning to the bottom (often with ventral surface uppermost), and walking.“

„Mating of H.rubra most likely occurs in the dark; the single example described took place during the day under a rock. Spawning is assumed to occur in cryptic locations, such as beneath the rocks in aquaria or pools.“

„We suggest that H. rubra feeds in the epigeal portion of its habitat and reproduces in the hypogeal portion. The absence of berried females and larvae from the epigeal portion of the anchialine pool habitat (observations by a number of researchers over 23 yr) indicates that the cinditions in the hypogeal environment may be more suitable for larval development than those in the epigeal region. These conditions may include waters of higher salinity and absence of visual predators.“

frugalfish · Post by **frugalfish** » Thu Mar 30, 2006 2:44 pm

Interesting. Thanks for the post.

Shrimpmania · Post by **Shrimpmania** » Sat Apr 01, 2006 9:37 pm

Post by **Mustafa** » Sat Apr 01, 2006 10:03 pm

Shrimpmania wrote:+1

Shrimpmania,

You have to stop making these +1 posts. I have been deleting most of them as fast as you make them if you have not noticed, but I've had enough. I will really have to ban you if this continues since I don't have time to go around deleting posts with no content. At least try to put some content into your posts that actually has something to do with the topic being discussed (this applies to most of your other posts, too, besides the "+1" posts).

Also, a "+1" will not force anyone to continue a topic if there is nothing to discuss at the moment. I hope I have made myself clear.

Thank you very much.

frugalfish · Post by **frugalfish** » Tue Apr 04, 2006 10:54 am

Over the last week one by one three new larvae have appeared, but still no major outbreak of them.

Today that changed as there was a major hatch of over ten new larvae during the night.

Although it's been mentioned that salinity levels and possibly other factors may have been contributing to the low or no developement of larvae I think I may have stumbled onto another one that I over looked

...nitrates. I've been monitoring my tanks more closely of late and I was surprised

to find a high (40ppm) nitrate level in the opae ula tank. The

nitrates have since been reduced by over half and continue to drop. Considering that the last four larvae made it to shrimphood I'm optimistic that this next batch should fair as well.

Post by **Mustafa** » Thu Apr 06, 2006 1:58 pm

Congrats again! Yes, shrimp in general absolutely hate nitrates although H. rubra has a much higher tolerance than most other shrimp. Currently I have a "huge" batch of 18 larvae floating around in my tank. Any number over 10 is considered a pretty large batch of larvae for these shrimp.

frugalfish · Post by **frugalfish** » Thu Apr 06, 2006 2:28 pm

My current batch is at 19.