#Marine/Freshwater

[foxsnails]

Drawing rainbow trout in my diary <3

[marinebioblr]

Close encounters!

My beautiful koi betta Bisby has had a jumping spider neighbor taking advantage of her tank light to hunt bugs under for some time, and recently they met face to face! Very happy to capture each of them acknowledging the other - and Bisby's quick look back at me as if to say "you're seeing this too right?!" 🧡

Edit ✨️ For all those concerned, yes, she does have a lid! I'd just cleaned and was hanging out right there where I filmed from at my office desk. If you are new to fish keeping, please invest in a good lid or when picking setups, favor tank kits that include one!

[randybutternubber]

My fish, The Gooch. She’s an elephant Nosed fish, Marcusenius schilthuisiae. She is scared of metal tongs and objects because elephant fish produce electrical pulses, kind of like a sixth sense, and the way it bounces off the metal is very noticeable to them

Her irl

[fishenjoyer1]

Fish of the Day

Today's fish of the day is the Alabama Cavefish!

The Alabama Cavefish, scientific name Speoplatyrhinus poulsoni, is known for being one of the rarest troglobitic fish species in North America. Discovered in 1967, by the time the alabama cavefish was scientifically described in 1974, there were only about 100 fish left. On any visit to the cave, only about 10 fish have ever been seen, but they are consistently different fish, so the estimated number is a little under 100, making them critically endangered. This also makes them a possibility for the rarest cavefish in North America!

Despite the large waterways connecting caves in Key Cave National park to several other cave systems, the Alabama cavefish has restricted itself to only one cave for reasons we don't understand. A search of over 120 caves in the surrounding area revealed no populations or signs of populations. With a range consisting only of Key cave in Lauderdale county, Alabama; these fish are constantly faced by the threat of extinction, and most of their worries are based on the limited home range, and waters entering the cave. Any water with chemicals, especially fertilizers and other agricultural runoff are a large concern. That along with competition from more aggressive cavefish, and predation from nearby crawfish. Due to their living situation and delicate population, much is unknown about these fish. But, let us go over what we do know!

The diet of the Alabama cavefish consists mostly of invertebrates found in the caves: copepods, isopods, smaller cavefish, spiders, beetles, and anything else it can find that will fit in its mouth. They grow up to a size of 2-3 inches in length. They have no eyes or pigment, and hunt solely based off of sensory protrusions that dot the head and sides, a trait evolved to handle the almost complete darkness. These fish have no breeding season, and instead breed based off of the environmental signal: when the caves flood in the winter and spring. Insufficient flooding can lead to years where no breeding or spawning occurs, and when it does females carry few eggs, and even fewer eggs hatch. Their lifespans, based off of the lifespan of Northern cavefish, are an estimated 5-10 years.

[saintgabe]

I think tumblr would be into the bright pink freshwater crab that was just discovered

[writheworm]

aquatic animal illustrations for friends

[serpentface]

Four culturally significant aquatic birds in Imperial Wardin- the skimmer gull, the albatross, the reed duck, and the hespaean.

The skimmer gull is a small seabird, distinguished by bright red beaks and a single, trailing tail plume. These are sacred and beloved animals with a long history of symbiosis with local fishers. They will intentionally attract the attention of fishermen, bringing them to shoals of fish that are too deep below the surface for the birds to reach. They then will snatch fish fleeing or caught in the nets, and will often be directly fed by their human assistants in an act of gratitude. They benefit tremendously from their sacred status and a taboo against killing or harming them, and can become absolute food-stealing menaces in seaside towns and cities.

The albatross is a seasonal visitor to the region, with this population migrating to small rocky islands in the White Sea to breed. The specific species occurring in this region is on the smaller side, and has a pale pink beak and soft orange legs. Albatrosses are common characters in regional animal folktales (usually as foolish, romantic types), and sometimes appear in tales as shapeshifters, usually turning into young women who have tumultuous affairs with lonely sailors.

Skimmer gulls and albatross are the most sacred animals of Pelennaumache, the face of God which looks upon the ocean, the winds, storms, maritime trade, fisheries, and broader concepts of luck and the infliction and deflection of curses. Killing either of these birds is considered to bring about disastrous bad luck (unless in the context of a proper sacrifice, most commonly in rites to bless ships and/or sailors with good winds and against ill fortune). The eggs of skimmer-gulls are free game and considered delicacies, while the preciousness of the albatross' single egg clutch is recognized and their consumption is generally discouraged (this isn't to say it doesn't happen).

Feathers of rightly sacrificed albatross and skimmer gulls are minor holy relics (ESPECIALLY gull tail plumes), and considered to be the ultimate good luck charm. The fortuitous find of a shed feather can also impart good luck and can be very valuable (the birds are sometimes poached for their feathers, though fears of the consequences are enough that this poaching is limited in scope). You will often see wealthier people wearing the feathers in hats and headdress, and any seafaring vessel worth its salt should have at least one aboard.

Both birds are evoked in the apotropaic Skimmer-Woman motif (in practice it generally has albatross characteristics, though is sometimes depicted with the tail plume of the gull).

The hespaean is a very unusual bird with two distinct species native to the region, one found exclusively in the western Black river system and its estuaries, and one found in the eastern Brilla and Kannethod river systems. They have very small pointed teeth in their bills, a trait virtually unknown outside of the flightless, beakless classes of birds (most prominently qilik). Their wings are vestigial and virtually nonexistent (with only two bony spurs remaining). These birds are almost exclusively aquatic and do not normally emerge onto land (they cannot walk upright at all, and must push themselves on their bellies). The legs of the Black river hespean develop blue pigmentation from their diet (the brighter the blue, the better fed and healthier the bird), which are waved above the surface during elaborate courtship displays. Both species are known for their haunting, warbling cries (very much like a loon, but more of a howling noise that develops into a shrill warble).

Hespaean build their nests in dense beds of reeds or small, vegetation-heavy river islands that provide some protection from predators. They raise their young during the height of the dry season (when more nesting surfaces are available and they can feed their young with more concentrated fish populations), which is an image of hope and resiliency during harsh dry times and the promise of the river's eventual bounty.

It is known that hespaean used to be caught as chicks and raised to help people catch fish (with ropes around their necks to prevent them from swallowing their catch). This practice is now very rare in the Imperial Wardi cultural sphere (mostly still practiced by the Wogan people along the Kannethod river, to whom these birds are also venerated animals) and has been largely replaced with the import of domesticated cormorants from the Lowlands to the southeast (which are more easily trained and can Usually be trusted not to attempt to swallow their catch).

These birds require large rivers that flow year round and have healthy, dense fish stocks. The population is in decline and they are now relatively rare, largely due to development and overfishing around rivers (and on a much larger timescale, the region becoming drier and water levels more irregular, and their competition with more versatile freshwater tiviit).

The reed duck is a migratory freshwater duck whose coming heralds the beginning of the wet season. They come to mate along rivers and wetlands during the final stretches of the dry season, timing their eggs to hatch with the rise in water levels and growth of the vegetation and insects they feed on. They have striking red-brown and gray plumage and very little sexual dimorphism (though the male is somewhat brighter in color and the flesh around the bill turns bright red during the breeding season).

Reed ducks are not domesticated, but some populations are semi-tamed and encouraged to return to certain sites to breed (the riverside temple to Anaemache in Ephennos attracts a massive flock of the ducks every wet season, continually blessing it with their presence and coating its grounds in droppings), and these stocks are the primary source of sacrificial ducks and coveted shed feathers.

Hespaean and reed ducks are the most sacred animals of Anaemache, the Face of God which looks upon freshwater (particularly rivers), rains, seasonal flooding, fertile earth/seasonal fertility, and wild plant life.

The hespaean is representative of Anaemache as the River Itself and the river as a provider of fish. This association comes down to their all-seasons presence in the rivers, and their population density being a signal of a healthy, well-flowing river with good fish stocks. Lands adjacent to hespean territory is often the most reliable and bountiful for human subsistence.

The reed duck in particular is the most venerated sacred animal of Anaemache, as representatives of Anaemache as a Face of seasonal fertility. Its coming announces the return of the rains and seasonal flooding that the region's agriculture relies on, and their cycle of fertility closely matches the cycles of the rivers and that of the earth itself (with their new life emerging with rains, flooding, and new vegetation in the wet season). There is no prohibition on hunting reed ducks (though proper rites and respect are expected for a sacred animal), and their meat and eggs is said to support female fertility and a healthy pregnancy.

[iwillwringyourneck]

[uncharismatic-fauna]

Settle In with the Sockeye Salmon

The sockeye salmon (Oncorhynchus nerka), also known as the red salmon, or the blueback salmon, is one of thirteen species of salmon endemic to the north Pacific Ocean. In their juvenile years they live in the open sea, but as fresh hatchlings and adults they can be found in freshwater rivers and streams. However, the subspecies known as the kokanee salmon are trapped in landlocked lakes and do not migrate as other sockeye salmon do. When migrating, the species can venture well inland to western North America and portions of eastern Asia, including Japan, Russia, and parts of Siberia.

Like most salmon, the sockeye is most famous for its lifecycle. It is an anadromous species, meaning that individuals migrate based on their life state. Newly hatched fry emerge from nests laid in the beds of freshwater systems, and spend their first 1-3 years before moving downstream to the ocean. There, they spend another 4-5 years in schools of up to several hundred, before they reach sexual maturity.

Beginning in July, mature adults begin the great migration back to the area in which they spawned. Once they reach their breeding grounds, males form into strict heirarchical groups and begin to court the available females. Meanwhile, each female digs a shallow nest in the riverbed and lays her eggs. Her chosen male partner-- or several-- lays a cloud of sperm over the eggs. A male may fertilize several nests before he dies; the female perishes soon after. The eggs, laid in clutches of up to 200, take approximately 40 days to hatch, at which point the cycle begins again.

As juveniles living in the ocean, red salmon are somewhat unremarkable. They have long, torpedo-shaped bodies that are generally silvery blue in color, sometimes with dark speckling. Individuals retain this coloring until well into their journy as adults, where males and females begin to significantly diverge. At their peak, adults may be anywhere from 60 to 84 cm (2 ft 0 in – 2 ft 9 in) in length and weigh from 2.3 to 7 kg (5–15 lb), with males being somewhat larger than females. Both males and females also change color; the head turns green, while the body turns bright red, although the color change is more striking in males. Finally, the shape of the male changes drastically, with the mouth becoming more hooked and the body growing a large hump.

Unlike other salmon, both adults and juvenile O. nerka feed throughout their lives. Fry and ocean-bound juveniles feed mainly on copepods and other zooplankton, while migrating adults also consume larger insects and invertebrates. Young blueback salmon are vulnerable to predation from larger fish such as lake trout, squawfish, and mountain whitefish, as well as larger invertebrates and frogs. Individuals living in the ocean are less predated upon, although they can still be caught by larger animals such as seals, sea lions, and sharks. Terminal-stage adults are large, easy targets and are consumed by a range of species; most namely bears and large birds such as gulls and eagles.

Conservation status: The IUCN considers the sockeye salmon to be of Least Concern. However, the species is listed on the United States Endangered Species Act. Populations have declined significantly throughout its range, largly due to overfishing, habitat degredation and the destruction of their breeding grounds.

Photos

NOAA Fisheries

Sergei Gorshkov

Roger Phillips

[respect-the-locals]

Daily Ray Fact:

*these are starting to get away from me 😅 whoops. Here's the actual fact*

The Tiger River Ray is a species of freshwater ray. This endangered species is endemic to black- and whitewater rivers in the upper Amazon basin in northeastern Peru. So little is known about its population and reproductive habits that it is impossible to say what its status is in the wild.

[tetrapodomorpha]

i love you lungfish i love you sturgeon i love you paddlefish i love you mormyrid i love you bichir i love you arowana i love you arapaima i love you electric eel i love you catfish i love you lamprey i love you bowfin i love you gar i love you freshwater freaks i love you evolution's most wonderful and most unique children i love you so-called monsters

[lake-lady]

I'm still trying to build up the community I made for loving all things water-related called lake-love! The Lakeheads TM (new term coined by a community member lol) have been posting the most awesome nature pics, freshwater and marine memes, and fish content so far. It's for people who love oceans, rivers, and wetlands too!! And really just for anyone who enjoys nature :) please let me know dm, ask, comment here) if you'd like to be invited and I'll add you!! Happy #lakeposting!!

[randybutternubber]

She reversed that shit like a car

[fishenjoyer1]

Fish of the Day

Today's fish of the day is the Giant isopod! 

The giant isopod, describes around 20 species in the Bathynomus genus, but most information is based on the Bathynomus giganteus, which is known for being the first giant isopod discovered, and the largest. Giant isopods, as an arthropod, have seven pairs of legs, four jaws, and compound eyes that have over 4,000 facets. The first set of legs is modified into an appendage for grabbing food and bringing it into the mouth, along with attacking prey, and all species with the  Bathynomus genus are similar, showing a lack of evolution between populations The full range of this family is unknown, but they can be found around the Indo-Pacific and the Eastern Atlantic ocean. The first time a giant isopod was found and recorded was in 1879 in the Gulf of Mexico, where the largest populations of giant isopods live, with a depth range of 310-2140 meters of depth. Outside of the Gulf of Mexico the other populations have a near identical depth range, and due to their similarity to their close land dwelling cousins, rolly pollies or woodlouse as you might know them, they are one of the textbook examples of deep sea gigantism.

Deep sea gigantism is an observed phenomena where deep sea animals have a habit of getting far larger than their more shallow relatives. Examples of this would be the giant squid, giant sea spider, deepwater stingrays, the bigfin squid,oarfish,  and many more. There is currently no encompassing explanation for why this phenomena is so prevalent, but there are multiple theories that have been proven partially correct by different genus. Food scarcity is often referenced, and often thought to be the reason for the giant isopods' large size. as without much food in the deep ocean organisms with the ability to store more food can live for longer periods without prey. Another explanation is the increase in dissolved oxygen, which is often a limiting factor in how large animals can become in their environments. A study of amphipod crustaceans in 1999 discovered their increase in size as the populations found in deeper waters directly increased with the amount of dissolved oxygen. The last and often most damning explanation for deep sea gigantism is the lowered temperature in deeper waters. This one can increase the size in animals by increasing cell size and lifespan, something that can also be found at the world's poles. Deep sea gigantism allows for the giant isopod to get anywhere between 19-36cm (7.5-14.3 inches) in length, with the largest recorded being 20 inches, about the size of a small dog. As compared to their close land relatives, which come in at less than an inch of length.

The diet of the deep sea isopod is remarkably similar to that of the land dwelling isopods, as the land dwelling isopods live off of dead or decomposing animals or plant materials. Which is similar to the diet of the giant isopod, which is an essential scavenger and carnivore in the deep. Once believed to be only scavengers, it is now known that giant isopods also actively pursue prey, usually fish, squid, shrimp, crabs, and other deep sea animals they can catch, as shown by a video of an isopod grabbing a dogfish shark and eating its face. These isopods can take down prey several times larger than them, but this may be only when in a confined space, as they don't swim fast and can only attack prey they can catch. But, as scavengers in the deep the giant isopod is primarily known for eating from whalefalls. A whalefall being when the carcass of a dead whale drifts to the deep seafloor, creating huge ecosystem hotspots and specialized animals in deep waters that feed almost exclusively on them. After eating from these whalefalls, giant isopods have been shown to go as long as 5 years in captivity without eating again, and for this reason when in the presence of food they eat far more than their body weight or size, willing to sacrifice locomotion in favor of excess, an easy trade considering they have no natural predators. Despite having no predators, they still have several behaviors similar to land pill bugs, as they can still roll into a ball shape, using their chitin armor to protect themselves, and burrow into the sediment to semi-hibernate.

The reproduction of the giant deep sea isopod is like that of many other arthropods, relying on eggs. In the spring and winter months the isopod females will begin brooding eggs, this is done in a pouch above the stomach and it will store anywhere between 20-30 eggs. During the brooding the female will burrow down into the sediment and refuses to leave until all eggs are hatched, at which point the juveniles are left. Captive isopods eggs measure 13mm in diameter and are thought to possibly be the largest marine invertebrate egg. Once born, these juvenile giant isopods will be as large as 4 inches in length ,and set off on their own in a stage called manca. At this stage, these are almost fully developed giant isopods, lacking only the last pair of legs. These will grow over time, and these animals gain size through molts. Their full lifespan is unknown, but estimated to be decades long, with the age of sexual maturity being unknown but estimated anywhere from 15-18 months.

Have a good day, everybody!

[bethanythebogwitch]

Wet Beast Wednesday: lampreys

Welcome to the first Wet Beast Wednesday covering an agnathan. What is that, you may ask? Why it means jawless fish. But they aren't really fish even though they live underwater and have gills. Taxonomy strikes again. Anyway, agnathans are more closely related to each other than to any bony or cartilaginous fish and they may represent an early stage in the evolution of vertebrates. There are only two living groups of agnathans: the hagfish (which I'll get to sometime) and the lampreys.

(Image: a pair of lampreys, one resting on rocky sediment and one swimming. They are long, green, slender fish-like animals with only dorsal and tail fins, several holes on the sides of the heads, large eyes, and no visible jaws. End ID)

Lampreys are sometimes mistakenly called eels due to their long and slender bodies. All 38 known species are elongated, scaleless animals with a funnel-shaped, jawless mouth called the buccal tunnel or buccal cavity. They do not have paired fins, only two dorsal fins and a tail fin. The head has one nostril on the top and seven pores on each side that allow water flowing over the gills to exit the body, similar to the gill slits of sharks. Adult lampreys have well-developed eyes while the larvae have weak eyes covered with skin. In addition, they have two simple parietal eyes, making lampreys the only four-eyes vertebrates. The mouth acts like a suction cup and is used to suction onto rocks or other animals. Inside the mouth is a rasping tongue that is used to scrape at food. You may think that all lampreys are parasites that feed on blood. This isn't the case, only 18 species are predatory and some of those are thought to be exclusively scavengers. The rest of the species either feed on algae by scraping it from rocks or never eat as adults, subsisting entirely on energy stores gained as a larva. The last common ancestor of all living lampreys (which is estimated to have either lived during the Jurassic or Cretaceous periods) is believed to have fed on blood as an adult. Lampreys are believed to be part of a sister group to all jawed vertebrates and are considered the most basal (closest to the ancestral form) of all vertebrates. They have cartilaginous skeletons and primitive, cartilaginous structures called arcualia instead of vertebrae. Lampreys are some of the most efficient swimmers and swim using a different method to other fish. Instead of using their fins to push themselves forward, lampreys use their fins to generate low-pressure zones in the water around their bodies to pull themselves forward. The pressure equalizing is what does most of the work of moving the lamprey, allowing them to move while expending little energy. In shallow water, the lampreys can use their suctioning abilities to crawl forward and are able to crawl over obstacles like rocks or ramps. Most lampreys are exclusively freshwater dwellers, but 9 species (all of which are carnivorous) live mostly in saltwater (though they can also live in large bodies of freshwater like lakes) and return to freshwater to breed. Of the 38 species of lamprey, only 5 species (in two families) live in the southern hemisphere. The remaining species are all members of the family Petromyzontidae and live in the northern hemisphere. No species lives in the tropics, seemingly because their larvae are not heat-tolerant.

(Image: a lamprey's mouth seen from below. It round and conical and ringed with multiple rows of sharp, yellow teeth. End ID)

The lamprey life cycle of lampreys starts in streams which adults will often migrate to reach. Adults will create nests called redds by using their suction to move rocks and expose the sediment below. Males use pheromones to attract females and the two intertwine with each other. The male presses a patch of heat-producing tissue to stimulate the female to release her eggs. The male fertilizes the eggs as they emerge. All lamprey species are semelparous, meaning they die after mating. In the case of lampreys that don't eat as adults, their adult forms exist only to mate and die, much like mayflies and some species of moth. Other species that can eat as adults spend up to 4 years feeding and growing before they mate. Larvae are called ammocoetes and once hatched, they are carried downstream to eventually settle on soft sediment. There, they burrow their rear halves into the sediment with their heads exposed. In this stage, they are filter feeders who need running water to bring plankton, algae, and bits of organic detritus to their mouths. Instead of the disc-like mouths of adult lampreys, ammocoete mouths are fleshy hood that enclose a sieve-like structures that filters particles out of the water. The lifestyle of ammocoetes is very similar to that of lancelets, which are extremely primitive chordates believed to represent some of the earliest stages of chordate evolution. Ammocoetes require water high in nutrients to survive as they capture only a small amount of water and therefore food. Ammocoetes are photosensitive, allowing them to change color in response to ambient light (becoming dark in the day and ale at night) and detect if they are properly buried. Depending on species, ammocoetes can grow between 10 and 20 cm (4-8 in) in length and they can spend between 1 and 10 years in this state. Metamorphosis to the adult form can last up to 4 months and lampreys do not feed during this process. Metamorphosis is synchronized between members of the same species.

(Image: three ammocoetes buried in sand with only their heads exposed. They are similar to the adults but pink, with small, barely-visible eyes, and their mouth are flexible and look like fleshy flaps. End ID)

(Image: two lampreys mating. they are coiled onto each other with one using its mouth to suction onto the midsection of the other. They are on a rocky stream bed. End ID)

Lampreys are used in science for several purposes. They are often used as a model organism when attempting to understand the biology of early vertebrates and extinct agnathans. They are also studied quite a bit for their nervous systems. Lamprey brains are very simple and likely represent very early stages of brain development in vertebrates. In addition, they are useful for studies of the transmission of electrical impulses between nerve cells due to their axons (the part of a nerve cell that conducts electricity away from the main body and to other nerve cells), which are large enough for microinjectors to inject test substances into them. Lampreys are capable of fully recovering from having their spinal cords severed, something that is of great interest to surgeons and neurologists. Lampreys have been used as a food source in many cultures around the world. Some species have toxic mucus and blood, requiring them to be cleaned before eating. Historically lampreys have been kept in captivity for use in food as well as other purposes. There are records of people being executed or tortured by being thrown into a pit of carnivorous lampreys. In the wld, carnivorous lampreys generally don't attack humans unless they are starving. In addition, there is a record of one Roman statesman named Lucius Licinius Crassus being scolded for being more upset over the death of his pet lamprey than over the deaths of any of his wives. Unfortunately, the thing a lot of people know lampreys for today is the sea lamprey (Petromyzon marinus) being an invasive species in the great lakes of North America. They have no natural predators in the lakes and feed on a lot of ecologically and commercially important species. Due to their lack of predators, multiple methods are used to try to reduce their numbers and keep them from harming the ecosystem. These include using barriers to keep the adults from migrating upstream to breed, release of targeted poisons called lampricides, and releasing sterilized males into the lakes to mate with the females.

(Image: two sea lampreys suctioned onto a fish. The fish is green and covered with black dots. The two lampreys are suctioned next to each other on the top of the fish's head. Their bodies are dangling off of the fish in different directions. End ID)

[theskyisdown]

SPINGLE THE FISH

He’s some kind of pleco, not sure what kind but thank you to @psalidodont for telling me he’s not a rubber-lip, and for the name! The shrimp absolutely adore him, they like riding on his back!