BEAUTIFUL DAMSELS: BAHAMAS REEF FISH (9)
THREE-SPOT DAMSELFISHPhoto credits: Melinda Riger @ Grand Bahama Scuba (except header image – Wiki-cheers)
THREE-SPOT DAMSELFISHPhoto credits: Melinda Riger @ Grand Bahama Scuba (except header image – Wiki-cheers)
The YELLOW STINGRAY (Uboratis jamaicensis) is one of several ray species found in the tropical western Atlantic ocean. They live in shallow water on sandy or seagrass bottoms, and are commonly found near coral reefs. Their light and dark splotchy colouring can rapidly change according to the surroundings and the need for camouflage. Look at the photos below with half-closed eyes and (apart from knowing perfectly well that there’s a ray there), the blending in is remarkable.
The yellow stingray feeds on small invertebrates and fishes. It can use its ‘wings’ to uncover buried / hiding prey by disturbing the sand. It also has a subtle ‘passive’ method of hunting by using its mantle to form a lethal ‘cave’ that attracts shelter- or shade-seeking prey.
Yellow stingrays breed in seagrass. They are quite prolific, breeding year round and usually having two litters a year of up to 7 young. This species is ‘aplacental viviparous’: the developing embryos are sustained initially by yolk and later by uterine milk. To find out more about viviparity, you’ll find a section at the bottom of this post where the inquiring may opt in… Not everyone’s sac of yolk, I quite understand.
The yellow stingray is innocuous towards humans, but can inflict a painful injury with its venomous tail spine. The threats to the species are (1) taking as bycatch by commercial fisheries; (2) collection for the aquarium trade; (3) negative impact from habitat degradation, both of reef areas and seagrass breeding grounds. For now, it remains common and widespread and retains its IUCN LISTING of ‘Least Concern’.
REPRODUCTIVE STRATEGIES (Marine Biodiversity, Canada)
As with all elasmobranchs, skate and rays are internal fertilizers. Internal fertilization is beneficial because it increases the likelihood and efficiency of fertilization by reducing sperm wastage. In addition, it ensures that the energy-rich eggs produced by the female are not consumed by predators, and that all the energy allocated to reproduction is passed to the embryos and not lost to the environment. This is especially the case for species that retain their embryos until the embryos have completely developed, a reproductive mode termed viviparity. Elasmobranches that practice viviparity are called viviparous (or live-bearing). There are many types of viviparity, which can be divided into two broad categories: aplacental and placental viviparity. Placental viviparity is the most advanced mode of reproduction, during which the embryos are initially dependent on stored yolk but are later nourished directly by the mother through a placental connection. This type of reproduction is not exhibited by any type of batoid. Ovoviviparity (or aplacental viviparity), on the other hand, is the only mode of reproduction employed by rays. In rays, the embryos rely on the substantial yolk within the ovulated egg only during the initial stages of development. After the nutrients stored in the egg have been consumed, the embryo ingests or absorbs an organically rich histotroph (or “uterine milk”) produced by the mother and secreted into uterus. The most highly developed of these strategies occurs in some rays in which the lining of the uterus forms tiny, finger-like projections (termed trophonemata) that increase the surface area for histotroph secretion. This form of nutrient supply (or maternal investment) results in very large offspring, which is characteristic of most species of ray.
For those now fluent in viviparity, the treat of one of Melinda Riger’s fabulous aquatic close-up photos – keeping a close eye on you…Credits: Melinda Riger of Grand Bahama Scuba, with thanks; Wiki for other images / source material; selected online pickings
The Queen Angel is one of several reef fish species where the difference in colouring between juveniles and adults is marked. They are commonly found in the waters of Florida and the Bahamas, with a range extending to the Gulf of Mexico. Adults can grow to 3.5 lbs (to mix metric with avoirdupois) and they can live up to 15 years. Like all Angelfish, they rely on their pectoral fins for propulsion as they forage on the reefs for their mixed diet of sponges, coral, plankton, algae, and even jellyfish. As the photo below shows, they have no problem swimming upside down…
Evidence suggests that adult Queen Angels may form ‘monogamous’ pairings. Brief research in the factosphere suggests that the proposition is somewhat tenuous. Maybe pairs just like hanging out - possibly to gain some territorial advantage – and anthropomorphising that into lifelong partnership terms may be overstating the relationship… Whether wed for life or not, the actual mating process is remarkably efficient. The pair snuggle up close, simultaneously releasing large quantities of sperm and tens of thousands of eggs. The fertilised eggs hatch within a day. Respect!
Photo Credits for the amazing main images: ©Melinda Riger (Grand Bahama Scuba), with thanks; header image WikiPic
This post is the first of a planned series on Bahamian reef fish. Those who follow this blog (I thank you both) may recall with horror (or worse, pity) my own efforts with reef fish, using a tiny cellphone-sized video camera. Misty stills culled from video footage. Enthusiastically wobbly movies as I struggle to swim and breathe simultaneously in an alien element. I am more underwater CLOUSEAU than COUSTEAU. However, thanks to Melinda Riger, who with husband Fred runs GRAND BAHAMA SCUBA, I have kind permission to borrow and display images from her stock of wonderful reef fish photographs.
The spotted drum fish (or Jack-knife fish) belongs to a large worldwide family, the Sciaenidae. Besides other drum varieties, the family includes ‘croakers’. These species are all named for the repetitive throbbing or drumming sounds they make. This involves the fish beating its abdominal muscles against its swim bladder. If I find out the reason for this (Species communication? Food call? Alarm? Warning? A piscine ‘advance’? Happiness?) I will add it here in due course. Here an example of an atlantic croaker from the excellent DOSITS site (Discovery of Sounds in the Sea)
The spotted drum is one of the few fish of the species to inhabit coral reefs – most are bottom-dwellers (often in estuaries), avoiding clear water. These fish tend to be nocturnal feeders, feeding on small crabs, shrimp and small invertebrates. As far as I can make out they are solely (or primarily) carnivore, and do not graze on algae of other reef plant life.
The photos above are of adult spotted drums. The ones below are of juveniles, and show the remarkable growth-pattern of these fish, from the fragile slender creature in the top image, through the intermediate phase of the one below it (with the amazing brain coral), to the striking adult versions above. People like to keep these pretty fish in aquariums; fine, I’m sure there are plenty to go round, but these ones look pretty happy to me in their natural reef environment…
Juvenile drum fish (school-age)
Finally, I’ve just come across this short video from a “Florida Aquarium”, showing how these fish swim. It rather looks as though it has been fin-clipped for some reason… or just damaged, maybe
The correct plural of ‘octopus’ is a singular mystery wrapped in tentacles and hidden beneath a rock. Shall we have the grammatical discourse first, or save it for later? Let’s have some
octopi octopuses octopodes to look at first… [oh, and it's definitely not 'octopussies', not even for 007]
An octopus courtesy of underwater photographer Melinda Riger, who with her husband Fred runs GRAND BAHAMA SCUBA
12 TASTY OCTOPUS FACTS TO ASTOUND YOUR FAMILY & FRIENDS
This remarkable picture (thanks, Wiki) shows an octopus unscrewing a container lid
THE CORRECT PLURAL OF ‘OCTOPUS’
There’s much debate about this comparatively unimportant question. Not even an octopus would care. The viable candidates are: octopuses; octopodes; and octopi. Since all are in common usage, none is ‘wrong’, though some are more correct than others…
1. OCTOPUSES An anglicised grammatical progression of a latin-sounding word to a logical plural, similar to ‘virus’ and viruses’. Only an extreme pedant would want to argue for ‘viri’ or ‘virii’. Similarly with bonus: “We all got boni for Christmas”. No, you didn’t. They were bonuses.
2. OCTOPODES the origin of ‘octopus’ is a Greek word ὀκτάπους, later latinised. The correct plural in Athens would have been ‘octopodes’. It is not derived from a 2nd declension latin noun, as often assumed, in which case the plural might indeed be ‘octopi’ (cf annus / anni; year / years). Using this etymologically accurate form in conversation might lead to a lonely life as people begin to move away from you. But you would still be in the right, if that matters to you so much…
3. OCTOPI see above. In a picky world, this is the least correct of the 3, being a pluralisation based on the wrong root origin (i.e. on latin, not greek), and therefore etymologically unsound. In practice, it’s quick and easy, and everyone knows what you mean, which is largely the point of language, I guess. Personally, I’d use octopuses if I ever used the word.
SUMMARY 2 is the most technically correct, and also the most likely to get you chucked off the side of the boat. Fully clothed. 1 is a logically correct anglicisation. 3 is a technically incorrect form, but long usage has made it acceptable to all but verbal Luddites. Push them off the boat too.
If you bothered to plough through that, you deserve some quality recreation. Even if you gave up in despair, you deserve these 2 videos (both taken in the Bahamas), which show the incredible way that these creatures move. Those who have never seen a live octopus will be amazed at their bodily transformations. If you only have time for one, see the top one – professionally done, and shorter. The lower one is a good amateur video, with a certain amount of diver heavy breathing and gurgling.
ADDENDUM This was never going to be easy! What about ‘cactus / cacti’, do I hear? Yes, cactus was known to Greeks as κάκτος (kaktos); but it was equally known to the Romans as ‘cactus’, not as a word that had to be imported by them from the Greeks and adapted. So the word’s root is as much latin as greek. No doubt that explains similar latin-origin ‘i’ plurals such as alumnus / alumni and stimulus / stimuli.
While fact-checking – a rare pleasure for me – I discovered a cheerful ‘Merriam-Webster’ video dealing authoritatively with the vexed ‘octopus plural’ debate (best skip the terrible ad)