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  • Relationships Between Aquatic Plants and Reproduction of Fishes
    into the depths of the body of water by diffusing the action of the waves and current near the shoreline Those species of fish that lay semi or adhesive eggs are well benefited by plants in that they anchor their eggs onto the leaves This prevents the eggs from falling to the bottom where they are more subject to be eaten by small invertebrates The eggs of fishes in dense growths of plants are further benefited by a more favorable hydrochemical environment Nikolsky 1963 Both live and dead plants help in this way The release of nitrates has a definite effect on the pH of a body of water When decaying plants release their nitrogenous organic compounds the water around them becomes soft and acidic In moderation this condition is necessary for the reproduction of many tropical and sub tropical fishes There is evidence that C0 2 has influence on the enzyme hatching mechanism of the killifishes which lay eggs directly on the plant The other common utilization of plants by nondestructive methods occurs when some fishes deposit their eggs in nests that are hidden in thick growths of plants Under another category we find plants that are modified by the fish in some way in order to facilitate a spawning site or nest Some fishes such as the Cichlids and the Centrarchids remove plant material from the spawning site in order to produce a more sterile environment for their broods Not only decaying vegetation but also large rooted plants are removed from the area in meticulous fashion by these intelligent fish Other nest builders assume a more positive relationship with aquatic plants Probably the basic documented case is that of the sticklebacks Gasterateoidea These relatives of the seahorses carefully select and dislodge the appropriate plants and weave them into a cylindrical nest in which spawning and early rearing of the fry occurs The family of Anabantids or labyrinth fishes also use bits and pieces of plants to weave into a thick mat of bubbles that the male forms at the surface of the water Amia calva the bowfin is reported to build some type of nest utilizing plant materials Nikolsky 1963 ADVERSE AFFECTS OF AQUATIC PLANTS ON FISH REPRODUCTION There is usually a definite competition that takes place in an aquatic community between the algal and rooted plants for available space and nutrients Bennett The balance between the two is delicate and the addition of excessive nutrients to the system favors the overpopulation of the phytoplankton Algal blooms occur and have definite adverse affects on fish populations and their reproduction The dense mats that are formed by the blooms shade the bottom and eliminate the slower growing rooted vegetation Aside from the eradication of floral spawning sites direct effects on the adults eggs and juveniles occur The introduction of toxins by the following genera of Cyanophycae is responsible for many lake and pond fish kills Aphanizomenon Anabena Nodularis Coelosphaerium and Glaeotricha Bennett 1963 Thick blankets of filamentous may also

    Original URL path: http://nanfa.org/articles/acplants.shtml (2016-02-01)
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  • Lake Lily, Cape May County, New Jersey, by Joe Yanik
    temperatures were in the mid 80s lowering the dissolved oxygen level but this could not be confirmed by testing Tests for phosphate and nitrate should have been performed as well but they weren t available at the time When present these pollutants have a tendency to drive the pH down into the acid range Why the lake would look acid yet test alkaline was the topic of the day s discussions When we deployed the nets we found that the lake was not dead as feared but was teeming with a few species of tough fishes Mosquitofish Gambusia affinis or G holbrooki the tenacious hell raising livebearer were thriving in this water The proximity and influence of the ocean was borne out by the presence of Silversides Menidia beryilina Sheepshead Minnows Cyprinodon variegatus Mummichogs or Bait Killies Fundulus heteroclitus and Striped or Longnose Killies Fundulus maialis all of which tolerate a broad range of salinities from fresh all the way up to brine saltier than the sea itself Striped Killies particularly are rarely found out of fairly salty water If we had not tested Lake Lily s water we would have sworn that it was salt water One pleasant surprise was catching a fish we had not seen before in our trips to Delaware Pennsylvania or New Jersey A substantial number of Rainwater Killies Lucania parva of all sizes were caught Though smaller than the common Bait Killie there is a resemblance and identifying juveniles can be difficult Rainwater Killies are more slender and delicate with a cross hatched pattern highlighting the scale margins They have a pretty spot on the anterior dorsal and possess gentle hues of yellow and orange in the belly region darkening outwards through the pelvic fins Larger specimens seemed intolerant of handling and were the first to whirl about with stress They also seemed prone to parasites as only these fish had leeches attached The Rainwater Killies make fine aquarium animals and like the Sheepsheads were prized by our group Although our collectors found the lake rich in forage fishes larger predators were notably absent Certainly we should have caught sunfish if any were about but such was not the case No fingerling bass or pickerel either The mice were clearly at play But without the spectre of predation looming around the corner this cannot be a picture of natural health As one resident put it How can we fix this lake At the time we were not sure it was broken but without the egret and the bass to put things in perspective it was not right either As the town struggles with defining the place the lake holds in its future there is true sentiment for preserving this resource The waterfowl are clearly choking the lake by the copious amounts of waste they produce Yet the community relishes their presence Will the community be willing to accept a dying lake as a casualty of this tradition Probably not for long Education may be

    Original URL path: http://nanfa.org/articles/aclakelily.shtml (2016-02-01)
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  • Eulogy for the San Joaquin River, by Ray Katula
    practices would have to change Indeed they should anyway Proposed legislation would essentially distribute water more fairly but agriculture would receive funds to conserve water prevent toxic drainage waste and increase crop yields These bills would allow greater flexibility to allow water for restoring the devastated formerly rich fish and wildlife resources that California once knew Other practices could help Much of the diverted water goes to irrigate cotton which is best grown where ample water supplies exist Drip irrigation could be implemented on many of California s crops and would save considerable water I ve heard from some farmers that such an idea is ridiculous maybe so but establishing a major growing industry in the middle of a desert is just as ridiculous and we have to start taking responsible steps to conserve water now to protect the continued viability of California The recent drought may seem like a fluke but droughts are a natural phenomenon of arid regions and we should utilize water as sparingly as possible Change in both attitudes and methods of irrigation are sorely needed The other huge problem for fish is introduced non indigenous fish species Bluegill black bass and silversides to name but a few have been introduced from east of the Rockies to enhance fishing The success of those introductions is frightening While black bass and bluegill do provide good sport the native Californian sunfish they displaced the Sacramento perch also does Like the bass it attains large sizes up to 21 Likewise as with the bluegill the Sacramento perch can adapt to small ponds and reproduces well in such conditions The primitive Sacramento perch is relatively less aggressive however and unable to compete with its foreign neighbors Thus it is virtually unknown in its once extensive California range This is merely one of the many examples of a common species nearly annihilated due to ill advised or hasty introductions by agencies supposedly designed to protect fish While we seek quick fixes to enhance the fish potential of a body of water the above example and more to follow show that no matter how carefully one plans the end effects of an exotic species introduction on a natural ecosystem cannot be predicted Most areas naturally possess good species to work with and efforts should be implemented to enhance their native fauna Once a species is injected into an unnatural ecosystem it utilizes food and space that would have been used otherwise Therefore there are no predictable and really justifiable introductions Two species considered successful introductions are the striped bass and the American shad These species however are anadromous they do most of their growing in the Pacific Ocean where food space and other resources are much more available Now we will list some specific examples of detrimental results following introductions or the depletion of water CLEAR LAKE SPLITTAIL Extinct The Clear Lake splittail was endemic to Clear Lake and its tributaries until its numbers severely declined due to competition from the introduced

    Original URL path: http://nanfa.org/articles/acsanj.shtml (2016-02-01)
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  • Those Creepy Crawlers Can Be Fun, by Ken Goldsmith
    common therefore not as much can be said about it If you do happen to find some of these transparent animals they also could be an interesting addition with other invertebrates Now just a few short comments on the Rotifers They are for the most part microscopic They would most commonly be found in the water filter of your tank in with the glass wool or polyester fiber Not only do these minute creatures help to clean the tank but they also are a vital part in many water treatment systems Worms are not very popular outside the aquarium let alone inside However there are several varieties of saltwater worms which are quite popular and beautiful In going back to freshwater the most common worms which you might have some rather unpleasant dealings with are your planarians flatworms They are found almost anywhere and sooner or later end up in a taiik These small animals are usually white and no larger than 10mm They can be hazardous in large numbers to juvenile or very small fish The most interesting feature of the Planaria is their ability to regenerate new parts If you cut one of these in lialf you would tlien grow two separate animals The other type of worm which you might be familiar with is the tubifex worm This is a tube building colonial worm in that when you see a group of these they are usually living in massive clumps possibly the size of grapefruits These worms are not dangerous to fish directly However because they generally live in dirty water there is a danger of introducing potentially toxic substances into your tank as well as the possibility of internal parasites if the worms are not cleaned thoroughly prior to feeding The person who uses this as food should be aware of the possible problems associated with this All in all it is best to keep worms out of the freshwater aquarium The phylum which lias the highest number of freshwater representatives is Arthropoda This includes the insects shrimp and crayfish It is the most prevalent phylum on the macroinvertebrate level The most abundant class in this phylum is Insecta Of course you would not want any of these in your tank since many are carnivorous However if you are not careful you may introduce them into your tank The larva are commonly found attached under rocks in the water or under the leaves of aquatic plants They live in small mud chambers where they go through their metamorphic changes Therefore by not washing rocks or plants thoroughly before introduction to the aquarium you might be inviting unwelcome visitors On the other hand it might be interesting to watch come of these animals metamorphosize from the larval to the pupal stage If you have a tank without fish you can do this as long as you remember to put them back in the local stream before they reach maturity Since many of these adult insects fly as

    Original URL path: http://nanfa.org/articles/accrawl.shtml (2016-02-01)
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  • Distribution of Fishes, by John Bondhus
    and common carp have decreased the range of many species Suitable habitat for some stage of their life history or spawning of a fish can restrict its range such as a fish from fast moving streams that can not spawn in still or slow moving water Thus trout and sculpins are usually found in hilly areas and sunfish in slow rivers and lakes Factors such as bottom type prevent walleyes and trout from spawning successfully in silt bottom lakes A specific disease or parasite could be a limiting factor if the parasite s range is limited to a specific area and of course fishing pressure near a metropolitan area can eliminate many of the longer lived species such as sturgeon and muskellunge Another factor is seasons of high and low water flow An early spring spawning fish who lays eggs in shallow water relying on floods to keep them covered with water wouldn t survive long in an area where water levels are lowering every spring Physical barriers are very important to distribution and in most cases limit at least parts of a species range Since fish can t walk or fly they are confined to river systems and the lakes in them that are connected to the river system The biggest reason river systems are used to show the range of a species is that once in a given river the species can spread rapidly through the system to all connecting lakes and streams until it reaches a barrier of some type Possible barriers are physical barriers such as waterfalls rapids and dams and the chemistry temperature and habitat barriers mentioned previously Once a species gains access to an area and occupies the area except where barriers prevent its spread it then waits until opportunities arise that allow it to cross the barriers Short barriers such as waterfalls and nearby landlocked lakes are often crossed during floods or by birds and animals carrying fish or fish eggs on them from one body of water to the other This type of spreading takes a lot of time and the number of barriers a particular species has managed to get over often gives a clue as to how long it has been in the area Waterfalls are especially good for this as in many cases they were not waterfalls throughout their history and most of the species above them were present in the area before the falls formed a time barrier A check of geological history often can give a date when the falls was formed Dams built by men are comparatively recent and their only real value is to stop recent fish introductions from spreading In many cases they give clues as to when or if a species was introduced into a river system by thoroughly studying the present distribution in the area and the dates of the various dams construction In the northern states glaciers eliminated all fish life up until 10 25 000 years ago and thus waterfalls

    Original URL path: http://nanfa.org/articles/acdistrib.shtml (2016-02-01)
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  • Underwater Photography in Kansas, by Garold Sneegas
    photograph at night Using a strobe also allows you to use a high f stop with a slow speed film to get the highest quality image I use Fujichrome Velvia slide film because I like the results and I can develop it myself using E 6 processing There are some real disadvantages to underwater photography Water turbidity temperature depth and the behavior of your subjects limit what you can do When you are in a stream just about everything is moving fish you your camera and in riffle areas sometimes the bottom is moving Steadying yourself and your camera is something that is a matter of practice and being comfortable in the aquatic environment you are in The greatest advantage to photographing fish underwater is that you can capture their peak spawning colors and natural behaviors in a way that can not be duplicated in an aquarium You can not duplicate the varying conditions of aquatic environments and the random interactions between migrating fish species and other aquatic inhabitants Capturing an image of spawning male darters displaying at their peak moment of excitement in the wild requires being in the right place at the right time You may be lucky and stumble onto this situation in a matter of minutes or you may have to spend hours submerged in 50 degree water monitoring an area This brings up the need for a cold water exposure suit Neoprene wet suits are the most common suits used for diving in cold water however I have found a high quality dry suit to be far superior If you are doing several dives a day in 50 degree water they are just about a necessity After spending hours snorkeling in shallow streams I have found it is better not to use a weight belt This adds a safety factor in that there is no way you are going to sink into deep water and it enables you to float into very shallow areas of a stream without kicking up a lot of silt or debris One other advantage of wearing a dry suit even in warm summer months is that it limits your exposure to parasitic critters such as leeches Light refraction between air and water is a phenomenon that an underwater photographer needs to be aware of Refraction between the air water interface of a divers mask has the effect of making everything a diver views appear 25 percent larger and closer When you are estimating the camera to subject distance underwater you are estimating the apparent distance the actual distance is 25 percent further away Because the submerged camera lens also has an air water interface the camera s view is the same as the diver s Waterproof camera housings will either have a flat or dome lens port If you place a 28mm land lens behind a submerged flat port refraction will cause an image distortion and change the viewing angle of the 28mm lens to that of a 35mm lens

    Original URL path: http://nanfa.org/articles/acunderwater.shtml (2016-02-01)
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  • Endangered Species Reintroductions - The Need for Good Science, by Jay DeLong
    strawberry darter were not orangethroats What if a well meaning aquarist had tried to boost the Strawberry Creek population of the orangethroat darter by releasing tank bred orangethroat darters or specimens transferred from another drainage This would not have been good for the strawberry darter Darters can hybridize I have crossed fantail banded and rainbow darters and I ve crossed rainbow darters and logperch Etheostoma x Percina I did these by hand and all crosses produced fertilized eggs I didn t hatch them Would the offspring be fertile I don t know If fertile would they spawn in the wild Again I don t know But hybridization has occurred among some rare pupfishes and among Gambusia species due solely to unwise releases And what if the two darter species had similar habitat requirements The aquarist would have succeeded in introducing a competitor as well The effects of such a well meaning reintroduction could never be undone My point Know your species and the science behind them An aquarist cannot know about the biology distribution and status of fishes just by reading popular aquarium magazines or field guides Contact people like Dr Page and ask if he s aware of pertinent research Contact your local university s zoology department and library Contact your state s fishery agency and get as much information from them as you can Discuss your ideas with them Also know your subspecies and don t cross them either in the stream or the aquarium if your intent is to produce fish for release This isn t just because a subspecies may one day be elevated to full species status it s also because they differ genetically If you cross two subspecies and release the progeny among one or both of their populations you will decrease the total amount of genetic information present Often the hybrids perform more poorly than the parents This undesirable outcome is called outbreeding depression If you see that individuals of the same species behave or appear differently in different streams or habitats e g pools vs riffles don t cross them and dilute their populations These differences may be genetic and may need to be preserved Learn About Ecological Relationships and Genetics Study ecology and genetics Why ecology Because complex interrelationships occur in aquatic ecosystems Learn about competitive interactions for resources and what happens when a species is removed or added from an ecosystem Why Because you ve got to develop an ecosystem mentality and get away from single species thinking If you are rearing a rare species which is now missing from its original stream you need to consider what has happened in that stream since the species disappeared Oftentimes other species fill in vacant niches Previously insignificant competitors may now be present in significant numbers Aquarium science has traditionally been about admiring and rearing fish and not about improving their ability to survive in the wild Aquarists do not breed fish for release No one who buys Amazon River fish thinks

    Original URL path: http://nanfa.org/articles/editjayd.shtml (2016-02-01)
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  • What to do About Introduced Species?, by Bob Bock
    the local species in 25 more years I fear that in many cases the damage we do may not become apparent until long after we re gone Who can say whether smallmouth bass stocked in a northeastern river today won t lead to local extinctions 50 100 or even 1 000 years later Sometimes introductions have consequences no one could have predicted For example the seemingly innocent stocking of one fish in Arkansas seriously jeopardized an endangered species in Utah In 1968 the Arkansas Game and Fish Commission introduced the Asian grass carp into Arkansas lakes The fish soon spread to the Mississippi River and became established The grass carp carried with it from Asia a parasitic tapeworm that eventually spread to red shiners a popular bait fish Anglers or bait dealers introduced the infested shiners into the Colorado River and by 1984 the shiners had found their way to the Virgin River in Utah Here the tapeworm infected the woundfin a native minnow already endangered because of dams and water diversions Not as resistant to the tapeworm as were the red shiners perhaps weakened due to competition with the shiners for food and space the woundfin suffered a rapid decline from which it has barely recovered To complicate matters even more human beings have also gained the ability to create new species where none existed before Last spring I was trying to catch some pumpkinseed sunfish for my 65 gallon aquarium In recent years this native species has become hard to find in my part of Maryland After hooking and releasing a dozen of the introduced bluegills I reeled in what I thought was the most colorful pumpkinseed I d ever seen On close inspection however this fish had a much larger mouth than a pumpkinseed and a pale orange trim around the edges of the fins I ve tentatively identified it as a cross between a pumpkinseed and a green sunfish How it got there I have no idea as there aren t any green sunfish around for miles Hybrids like this one though are often stocked as it s assumed they won t reproduce But in a recent posting on the NANFA E mail list Garold W Sneegas reported that a small percentage of bluegill x green sunfish hybrids that were stocked in a Kansas pond had indeed reproduced Such hybrids often grow larger and are more tenacious than either parent species stiff competition for the native fish that are forced to share their environment with them And we can only expect the competition from man made hybrids to get worse as genetic engineers tamper with the genes of existing species to create fish ever more suited to sportfishing To be sure the Genie s already out of the bottle and there s no chance of returning things to the way they were before Europeans came to this continent Once a species becomes established it s difficult to eradicate And as much as I hate to admit

    Original URL path: http://nanfa.org/articles/bockedit.shtml (2016-02-01)
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