Last night I had an interesting conversation with our lovely 360 sister Cyn (onemountainheart), let me tell you this is one smart lady and a very observant one when it comes to nature, brooks and streams. We all know her interest is fishing and I’m into micro-biology but alas not marine biology haha. Being already very late at night and by this time I think the sleepy giggles got a hold of both of us, just as we were saying good night to each other she asked me one quick question which in turn turned into an interesting topic.
Cyn wondered if I knew what the type of gel fungus growth is that attaches itself to wood in the lakes. To my knowledge there are many and so now it was to sort it out which one it could be and this is where I headed into the WRONG direction. My first instinct was in the Bryophyta family – moss as we know it where Cyn agreed that yes she also called it some kind of fungus moss. This made me turn towards all the fungus and algae that is beneficial in our ecosystem such as the protoctists are defined by some as eukaryotic microorganisms with the exception of animals and plants and including fungi and algae, slime moulds and other obscure eukaryotes.
All algae have photosynthetic machinery ultimately derived from the cyanobacteria, and so produce oxygen as a byproduct of photosynthesis, unlike non-cyanobacterial photosynthetic bacteria. It is estimated that algae produce about 73 to 87 percent of the net global production of oxygen, nitrogen and all that good stuff - which is available to humans and other animals for respiration. (I’ll be talking more about nitrogen and fish further down of this post)
Cyanobacteria have been included among the algae, referred to as the cyanophytes or Blue-green algae, (the term "algae" refers to any aquatic organisms capable of photosynthesis) though some recent treatises on algae specifically exclude them. Cyanobacteria are some of the oldest organisms to appear in the fossil record dating back to the Precambrian, possibly as far as about 3.5 billion years. Ancient cyanobacteria likely produced much of the oxygen in the Earth's atmosphere.
Cyanobacteria can be unicellular, colonial, or filamentous. They have a prokaryotic cell structure typical of bacteria and conduct photosynthesis on specialized cytoplasmic membranes called thylakoid membranes, rather than in organelles. Some filamentous blue-green algae have specialized cells, termed heterocysts, in which nitrogen fixation occurs. The perfect prokaryotic cell consist of miscalgnous sheath covering cellwall that consist of pectinic substance and sachride while the cellwall consist of 4 layers, an outer and inner layer and a middle layer while the fourth layer is attached to plasma membrane and the protoplast consist of 2 part peripheral coloured partknown by chromatoplasm which contain the pigments in case of algae and contain photothynsis producte. g in cyanobacteria it contain chlorophylla, b-caroteinand c-phycocyanin and c-phycoerthyrin.
As the night progressed and Cyn asked about the possibilities of warm water causing the fungus I replied with a no because then it would create harmful side effects and hostile to the ecosystem, and then I went on to explain the water conditions and so on. It finally got to be too late and we had to say good night but I did promise I would have a look at it the next day.
Marine-biologist examining the water
As I closed down the computer something Cyn had said came to my mind – she mentioned the fact that there were no trout in that particular lake where she had found that fungus. I realized I had been looking in the wrong direction, (oh blush)
I should have been looking at the harmful fungus such as Saprolegnia.
Saprolegnia
How Saprolegnia Affects Fish
As a member of the Oomycete family, the genus Saprolegnia is considered an opportunist facultative parasite, which is saprotrophic and necrotrophic. Fungal spores may be transmitted by hatchery fish, wild fish, eggs, water supplies, and equipment. Fungal patches may consist of one or more species of Saprolegnia and become grayish due to the presence of bacteria and debris. It has been suggested that certain bacteria may repel or are antagonistic to Saprolegnia.
Saprolegnia
Saprolegnia has a large impact on salmonids, especially those in aquaculture. However, it can also infect a number of other teleosts as well. Channel catfish, pike, bass, trout, elver and suckers, roach, orfe, carp, tench, lamprey, sturgeon, barramundi, tilapia, and mullet have been infected with Saprolegnia. It has also been associated with tropical fish, including the kissing gourami, guppy, swordfish and platyfish.
Infected fish
If untreated, Saprolegnia leads to death by heamodilution, i.e., osmoregulatory failure. Time to death by saprolegniasis is dependent on the initial site of the infection, type of tissue destroyed, growth rate of the fungus, and the ability of the individual fish to withstand the stress of a fungus invasion.
Infected fish
While there is no evidence that Saprolegnia causes systemic infections or produces toxins there can be a slight inflammatory response on the fish to fungal infections. Fish with severe Saprolegnia infections appear lethargic, lose equilibrium and generally do not recover.
Life cycle of Saprolegnia
Water temperature and Saprolegnia
Saprolegnia has a fairly wide range of temperature tolerance, from 3°C to 33°C, which appears to reflect the thermal preferences of the host. However, sudden changes in temperature can make fish vulnerable to saprolegniasis, due to the increased physiological stress.
Nitrogen and Fish
Determining the nutritional value of whole fish fed to other animals. Fish are a main food source for seals, sea lions, porpoises, certain birds and even other fish, and are an important seasonal delicacy for bears preparing for winter hibernation. Zookeepers may use the regression equations to estimate the amount of protein fed to their fish-eating charges. Similarly, biologists may use the regression equations to estimate the protein intake of wild animals after observing the size and species of fish eaten.
Studying the N budget of a stream. Nitrogen is often the first limiting nutrient for algae growth in water. The decomposing carcasses of spent migratory fish such as salmon may be an important source of N enrichment in some streams. Since fisheries managers frequently count the number of returning spawners in streams, the contribution of spawner carcasses to the N budget of streams can be estimated using regression relationships once average spawner weight is determined.
Bears and other wild life mammals feeding on the fish carry then the fish onto land where it either decays or the mammal excretes thus giving its nutrients to the ecosystem.
In closing I’d just like to mention that if any fisherman/woman finds any type of algae or fungus type growth near and in waters where the fish seem to be declining it’s a good idea to let fisheries and wildlife be aware of that to eradicate the culprit before it makes too much damage.
Thank you Cyn for an enlightening topic.
Hope you’ve enjoyed this little bit of marine biology.
Wish you a very relaxing and safe weekend 
Huuugs and love to all
Wabbit
