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发表于 2011-8-31 22:48:49
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来自： 中国上海
5 天
11 天
14 天
浪费不少时间和轮虫、球藻、矽藻。完全的失败。孵大和藻虾易，养活清洁虾幼苗难。
有兴趣的可以阅读这个文章。
原文出自 www.reefsuk.org
After having considerable success at breed, raising and selling a number of Tropical freshwater fish species I decided it was time venture into the world of marine ornamental fish keeping. After reading up on the subject I slowly stocked my system. I had notice several times, in my local aquarium shop, a number of cleaner shrimps bearing clusters of bright green eggs around their pleopods, swimming appendages along the ventral surface of the tail. I was keen to find a marine species that could I work with and hopefully achieve the same success as my freshwater attempts. I purchased two specimens and this an account of my success to date. The Indo-Pacific White Striped cleaner shrimp, Lysmata amboinensis is an invertebrate that is commonly kept by both experienced and new comers to the marine aquarium hobby. Like all members of their class, Crustacean, they are sensitive to abrupt changes in water parameters and therefore must be acclimatized to new tanks slowly. Thermal shock seems most important to avoid, so a long floatation of the purchasing bag is necessary. Once this achieved however they are hardy invertebrates. When kept in groups they are often on view during the day, displaying their vivid red and white colours and waving their long white antennae. The colouration of L, amboinensis is very similar to the closely related Atlantic White striped cleaner shrimp, Lysmata grabhami, which can be the cause of some confusion, as both are sold as cleaner shrimps. They both have red dorsal sides with a thin white line running from the anterior (head) to the posterior (tail), however the differences are on the telson (tail) markings. On L,amboinensis the thin white line terminates before the telson, where it branches to form an inverted T shape. On either side of the telson are two white blotches and a white triangle in the centre. On L, grabhami either side of the teleson is a faint white line.
Feeding
In the natural environment of the Indo-pacific waters these shrimp perform a cleaning service for fish of the reef, as a prime source of food. Pairs or occasionally large congregation occupy "cleaning stations" waving they're long white antennae and moving their bodies from side to side. Fish can often be seen enjoying the attention as the shrimp pick of parasites and diseased skin. Larger fish, such as Groupers and Morays, seem to control their predatory instincts and allow the shrimp to enter their mouths. Here the shrimp clean away trapped food from with the host's teeth providing a mutually beneficial service to both recipients. In the aquarium they also perform these services on other tank mates of a suitable size. These attentions however often tire and the shrimps adapt very well to most, if not all forms of aquarium food. They are also great scavengers, feeding on any missed food items, a function that it beneficial to the tank as it relieves pressure on the filtration system. Due to their undemanding feeding habits in a sort period of time it is even possible to feed them by hand, as they swim upside down at the water's surface hungrily searching for food with their legs. They are particularly fond of members their own class Malocastrca, ie pacific krill, Mysid shrimps or prawns. I found suspending a prawn by a piece of cotton every other day keeps them well fed and healthy.
Reproduction
The reproductive strategy of L. amboinensis seems to have been an enigma to aquarist until recently. Aquarist have kept these shrimp on the assumption that they were gonochoristic, in other words having separate sexes, a real shock when one morning you find both individuals of a so called pair baring a full clutch of viable bright green eggs. The answer is naturally that L. amboinensis is hermaphroditic, meaning that each individual is capable of producing both ova and spermatozoa. Each individual therefore acts as the opposing sex, with one using sperm to fertilize the others eggs and visa versa. The question now arises why not simply self-fertilize. If individuals are separated after copulation two/three clutches of eggs can still be fertilized by means of sperm stored. After this period however no eggs are produced suggesting the stored spermatozoa either die or are released. This lack of egg production also indicates that L, amboinensis is unable to self-fertilize, an adaptation that is in following with many hermaphroditic spawns.
Egg Production Frequency
It took me sometime observing the egg production cycles before I could determine the gestation period. A day before the shrim p is ready to lay the eggs onto the pleopods (Swimming legs) they can be seen as a green area through the carapace (Thorax body shell). This is best viewed from the sides, above the 2nd and 3rd pair of walking legs. When lying the eggs, the shrimp bends its abdomen and uropods (tail flukes) downwards and excretes them from the thorax to the inter-spaces of the pleopods. Once completed anything from 500-1200 bright green eggs can be seen. As the eggs grow this vivid colour fades, turning to a dull cream/light brown a few days prior to hatching. On the day of hatching two things are obvious. First the clutch is so large it seems ready to fall from the shrimp and secondly the developing larvae eye can be seen as black dots. The gestation period may vary with temperature or salinity but at 25 degrees and a specific gravity of 1.022-1.023 hatching always occurred on the 15th day after being laid. This will occur between half and one hour after the aquarium lights go out. The egg-baring shrimp swims inverted releasing hundreds on tiny larvae into the water column. The sight is quite spectacular and one of the great highlights of the hobby. To view the event it is best to use a low powered torch though as turn the aquarium lights back on merely delays the process. If hatching occurs in the main display tank the torch can also be used to concentrate all the larvae in one area for collection. This is because in their larval stage they exhibit positive phototropism, to the layperson they simply move towards a light source. This is function that orients them to the seas surface during the day were they feed on various phyto and zooplankton. Remember the larvae are vary delicate at this stage so don't use a net to catch them, siphoning is much better. If the shrimp has been kept in a separate breeding tank it is a good idea to carefully remove the parent shrimp after hatching to avoid predation.
Breeding Tank
The system I used as a breeding tank can only be described as prehistoric. An 18"x12"x10'' all glass aquarium, a hood holding an 18 watt Fluorescent tube and a simple under gravel filter run by an air pump. The output of the pump was turned right down to stop physical damage to the delicate larvae. On the uplift pipes I added capsules containing carbon media for added filtration. The water temperature was 25c and the salinity maintained at a specific gravity of 1.0225. Due to the limited filtration capability of the system low percentage water changes were done everyday. The short description of my setup clearly shows that such breeding endeavours needn't be restricted to large organizations with the latest filtration technology, indeed simple is often best! The average hobbyist can achieve excellent results with a little effort and it is within this area, potential for captive breeding of tropical marine organisms has the greatest chance of expansion.
Larval feeding
The new hatched shrimp are fully capable of prey capture and will actively hunt astonishingly large items. Due to a lack of knowledge at the time I simply used brine shrimp naupli. The artemia eggs take between 36-48hrs to hatch, so two days prior to the L, amboinensis eggs hatched I made up a saline solution, around 1.020 SG in a pint glass and added some artemia eggs and an air hose. The hatching of both artemia naupli and L, amboinensis larvae therefor co-insides providing an adequate but ideal, food source. Although I didn't at the time the artemia should be nutritionally enhanced because contrary to popular belief new hatched brine shrimp are very nutritionally poor, and after 6 hrs of hatching they lose the majority of their small nutritional content. Nutritional enrichment is very easy because artemia are filter feeders and so take up particles that are suspended in the water. Simply add a vitamin supplement and algae wafer to the hatching jar and the naupli will take up the food from the solution. The naupli are effectively energy capsules, containing the base nutritional requirements for the L, amboinensis larvae.
Development
Immediately after hatching the shrimp larvae must be totally self-sufficient. They are capable of hunting and at this stage they use their future walking legs to swim. This is achieved by oscillating these legs enabling them to swim backwards and often spiralling at the same time. The uropods (Tail) are partially formed although not in functional use, primarily as escape reaction. The compound eyes are clearly noticeable although the eyes stalk has not formed yet. At this stage I roughly estimated between 800-1000 larvae had hatched. Over the next day it appeared that very few larvae had died, presumably surviving on small amount of energy reserve. By the next morning the larvae where two days old and overnight there appeared to be around 2-5 percent mortality. However the remaining larvae's thorax where orange, indicating that the artemia were being actively hunted and consumed. Good sign at this early stage! The problems started by the next morning. Around 50 percent of the larvae had died. This is presumably accounted for by the low/ unsuitable nutritional quality of the artemia naupli. By the fifth day prior to hatching the larvae seemed to have metamorphosed into their second larval stage. The eyestalks were forming and the characteristic red pigmentation was appearing on the abdomen. At day eight more pigmentation, again red was forming on the uropods. The antennae can be seen and are beginning to split at the end. This is also clearly seen in the image of the 11-day-old larvae. The first signs of the feed claws are now beginning to form. This is seen as thickening at the end of the last leg on the right side. Again this development is emphasized in the images of the 13-day-old larvae. Unfortunately I didn't preserve any specimen in-between this stage of development and the next at 73days old, so there is considerable differences in the larvae morphology. By the 73rd day the remaining larvae were around 10mm long, which was considerably slower growth rate than I had expected. I put this down to the poor food quality that I was feeding them and possibly the prey density. At this stage though the antennae had groan and there were now three feeding leg per side developing. The shrimp now appeared to hold a posture that you expect, when standing on the substrate, but they still swam backwards in the water column. The two photos of the 83-day-old larvae show the advance development of the telson although not in full functional use.
Future recommendations
Although I have not managed to raise these shrimps from hatching through to rearing a second generation which a s got to be the true testament of success, I am still trying. These are just a few things I am going to change for the next attempt and I hope that any other enthusiastic hobbyist will find this article helpful not too boring. Smaller rearing tank to increase prey density and thus prey capture. I have read that increasing prey to extremes can have ill effects though as it decreases the desire to hunt. Artemia enrichment. Using conventional vitamin supplements and algae wafers. |
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