SILVERSIDES: BAHAMAS REEF FISH (32)


silversides-school-melinda-riger-g-b-scuba

SILVERSIDES: BAHAMAS REEF FISH (32)

I have no idea if there is a collective noun for a large group of silversides. ‘Frenzy’ would cover it, but that is reminiscent of ‘feeding freezing’ which has a specialist meaning – and anyway, silversides are crazy even when they aren’t feeding. 24/7/12/365 as far as I can make out. I think ‘a panic of silversides’ might be the answer. They are just… all over the place at high speed. Sometimes swirling around pointlessly, other times moving in unison and suddenly all changing direction simultaneously, like a single creature made of tiny shards of silver.

silversides-school-melinda-riger-g-b-scuba-copyfish-frenzy-melinda-riger-gbs

There are quite a few silverside species around the world. The ones in the Bahamas are Atlantic silversides (Menidia menidia), also known in the north east of the United States as ‘spearing’. They seem to exist for two purposes. The main one is to be breakfast, lunch or dinner for larger fish, sea birds and shore birds. The other is for their usefulness in scientific research because of their sensitivity to environmental changes. 

silversides-melinda-riger-g-b-scuba-copy-2silversides-school-melinda-riger-gb-scuba

In one sense they are easy prey for predators. A determined fish will always manage a snack by swimming into the middle of a panic and (probably) simply by opening its mouth wide. On the other hand, their sheer numbers coupled with the speed and randomness of movement mean that a single may find a degree of safety in numbers. It’s hard for a predator to target any individual fish in the general melee and confusion. Silversides also favour seagrass beds, which give some shelter and protection – and a reasonably safe place to spawn. Or, as some of these photos show, they will hang around wrecks or squeeze into rocky spaces in the reef.

silversides-melinda-riger-g-b-scuba-copysilversides-melinda-riger-g-b-scuba

A panic of silversides apparently pouring like a waterfall down through a gap in the reefsilversides-waterfall-abaco-kay-politano

WHAT DOES A STATIONARY ATLANTIC SILVERSIDE LOOK LIKE?

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Some time ago we used to go to the reef at Fowl Cay Marine Preserve with Kay Politano, and I would snorkel with a small and very basic lo-res underwater camera. I was hampered by being a disgracefully feeble swimmer; by not having snorkelled for a length of time calculable in decades; and by being a complete novice at underwater photography.  Despite these not inconsiderable disadvantages I managed to cobble together a few short movies on my computer (I was new to that too). Here’s one that nearly works, in that it gives an idea of what happens if you ‘swim with silversides’. I know you scuba guys all swim with sharks, but cut me some slack here please…

Photo Credits: Main photos Melinda Riger of Grand Bahama Scuba; Silverside Waterfall by Kay Politano; motionless silversides by FISHBASE.ORGMusic: Goldon Giltrap, ‘Fast Approaching’

HOGFISH: BAHAMAS REEF FISH (31)


Hogfish at cleaning station ©Melinda Riger @GB Scuba

HOGFISH: BAHAMAS REEF FISH (31)

Hogfish. Fisherman’s delight… getting ‘high on the hog’. This wrasse species Lachnolaimus maximus is a reef denizen, especially where gorgonians are found. It has the distinction of being the only known member of its genus, and because it is IUCN listed as vulnerable, there are strict regulations governing bag, size, and gear limits to protect the species from overfishing.

Hogfish ©Melinda Riger @ G B Scuba

The hogfish gets its name from its long ‘pig-like’ snout, coupled with its rootling behaviour on the sea floor for crustacean prey.

Hogfish ©Melinda Riger @ GB Scuba copy ed Hogfish foraging ©Melinda Riger @ GB Scuba

GENDER STUDIES: IT’S COMPLICATED

The hogfish is a sequential hermaphrodite, meaning it changes sex during different life stages. Juvenile hogfish are female, but mature into males at around 3 years old.

Hogfish ©Melinda Riger @ G B ScubaHogfish ©Melinda Riger @ G B Scuba copy

Hogfish social groups are organized into harems, where one male will protect a group of females in his territory and mate with them.

Hogfish ©Melinda Riger @ GB Scuba Hogfish with isopods ©Melinda Riger @ GB Scuba

CAUTIONARY NOTE Capt. Rick, a loyal follower, has made another of his pertinent comments: “A bit of caution is necessary here! There is some history in the Bahamas of mild to severe Ciguatera poisoning from Hogs. Our M.O. was to only eat Hogs no larger than 5 or 6 lbs. Temporary or permanent blindness, paralysis, and even death is possible with bigger Hogs”. Ciguatera is also a problem with, for example, ‘cuda on Abaco. Those caught on the Marls (west) side are ok to eat; those from the east side have to be treated with circumspection…

Hogfish (with isopod above eye) ©Melinda Riger @ GB Scuba

Credits: all fantastic fish fotos – Melinda Riger at Grand Bahama Scuba

SPONGES ON THE REEF: A COLOURFUL MISCELLANY


Brown Tube Sponge ©Melinda Riger @ G B Scuba

SPONGES ON THE REEF: A COLOURFUL MISCELLANY

It’s time to take an up-close look at some of the sponges you may find as you snorkel or scuba round the reefs of the Bahamas. I am always amazed by how bright and colourful they are, and by their many different shapes and sizes. Even the unpromising sounding (slightly medical, even?) BROWN TUBE SPONGE turns out to be fascinating to examine closely. Here are some more sponge species. 

CANDELABRA SPONGECandelabra Sponge ©Melinda Riger @ G B Scuba copy

STOVE PIPE SPONGEStove Pipe Sponge ©Melinda Riger @ G B Scuba

PURPLE VASE SPONGEVase Sponge, purple ©Melinda Riger @ G B Scuba

BRANCHING TUBE SPONGE WITH ROPE SPONGESponges - Branching Tube Sponge with rope sponge ©Melinda Riger @ GB Scuba

PURPLE TUBE SPONGEPurple Tube Sponge ©Melinda Riger @ GB Scuba

PURPLE SPONGE WITH GIANT ANEMONEPurple Sponge : Giant Anemone ©Melinda Riger @ G B Scuba

VASE SPONGEVase Sponge ©Melinda Riger @ G B Scuba

The above sponges represent a fraction of the sponge varieties found on Bahamas reefs. I’ll post some more quite soon. All this has made me want to go for a snorkel. But right now I am 30 miles from the sea. And I have no gear…

HANG ON A MOMENT! WHAT IS A SPONGE WHEN IT’S AT HOME?

It’s really very simple: if you are ever asked the question, just reply “a sponge is a primitive sedentary aquatic invertebrate with a soft porous body that is typically supported by a framework of fibres or calcareous or glassy spicules. Sponges draw in a current of water to extract nutrients and oxygen”.

AND WHAT, PRAY, IS A SPICULE?

You’re having a laugh… if you seriously want to know, read the abbreviated version about them HERE. And admire this microscopic collage of ‘demospongiae spicule diversity’ made available by the wonders of Wiki and the research of about 20 credited scientists.

Demospongiae_spicule_diversity

All photos: Melinda Riger, Grand Bahama Scuba. Tip of the hat to Wiki and scientists

WHALE-WATCHING: THE APPLIANCE OF SCIENCE


Blainville's Beaked Whale, Sandy Point, Abaco 14 (Keith Salvesen

WHALE-WATCHING: THE APPLIANCE OF SCIENCE

The Bahamas Marine Mammal Research Organisation has just celebrated its 25th year of existence. It was formed in 1991. The omnivorous leviathan Amazonus giganticus emerged in 1994 and the invasive species Megacorpus googleii not until 1998. A full 10 years later the first garbled recordings of Sarahpalinus illogicus were made. And all the while, a watchful eye was being kept on the cetaceans of the Bahamas – researching, counting, measuring, identifying, recording, poop-scooping, analysing samples, tagging, comparing, protecting and conserving. 

Blainville's Beaked Whale, Sandy Point, Abaco 20 (Keith Salvesen

As the years passed, so the science and technology evolved and became more sophisticated. Researching became at the same time easier, yet more complex as the organisation’s remit expanded to accommodate the vast increase in data collection now made possible by refined techniques. Here are two very recent examples – 25th anniversary projects, in fact – with thanks to Charlotte, Diane, their team and their colleagues in linked organisations.

TAGGING BLAINVILLE’S BEAKED WHALES

Last month, a tagging project started, involving suction cups being attached to the backs of BLAINVILLE’S BEAKED WHALES. The purpose of the research is to compare the foraging efficiency of the whales in Abaco waters with those of Andros, the second part of the project. I imagine this will provide valuable insights into the whale movements and behaviours in each location as well as such issues as the comparative availability of the food supply, and other factors that may affect expected foraging patterns. 

The tag is moved towards an adult male. Note the aerial (antenna?) at the back of itTagging a Blainville's beaked whale with a suction cup 1

Planting the tag on the whale’s backTagging a Blainville's beaked whale with a suction cup 2

Successful suction!Tagging a Blainville's beaked whale with a suction cup 3

The tag in placeTagging a Blainville's beaked whale with a suction cup 4

The tag is tracked for 18 hours, after which it is retrieved and the recordings can then be analysed back at BMMRO HQ in Sandy Point. So far, an adult male, a young male and two adult females have been tagged. Each female had a calf, but these were not tagged.

Female beaked whale with her calfBlainville's beaked whale female and calf

AERIAL PHOTOGRAMMETRY USING A HEXACOPTER

Drone technology is rapidly expanding as new uses for them are devised. BMMRO in conjunction with NOAA have used a sophisticated HEXACOPTER to take the first  PHOTOGRAMMETRY images of Blainville’s beaked whales. These aerial photographs were taken from approximately 100ft altitude. But note: not just anyone with a $50 drone can do this: the project required flight clearance from the Bahamas Department of Civil Aviation and a permit for research on marine mammals granted by the Bahamas Department of Marine Resources.

 Blainville’s beaked whale photogrammetry image – adult male (note ‘erupted’ teeth) Blainville's beaked whale photogrammetry image - adult male (note 'erupted' teeth) BMMRO

 Blainville’s beaked whale photogrammetry image – female and calf Blainville's beaked whale photogrammetry image - female and calf BMMRO

STOP PRESS Two additional images from the latest batch Blainville's beaked whales photogrammetry image - BMMRO  Blainville's beaked whales photogrammetry image - BMMRO

Photogrammetry: the science of making measurements from photographs. Applications include satellite tracking of the relative positioning and alterations in all Earth environments (e.g. tectonic motions etc), research on the swimming of fish, of bird or insect flight, and other relative motion processes. The results are used to guide and match the results of computational models of the natural systems. They help to invalidate or confirm new theories, to design novel vehicles or new methods for predicting or/and controlling the consequences of earthquakes, tsunamis etc, or to understand the flow of fluids next to solid structures, and many other processes. (Wiki-précis)

Hexacopter (6 rotors)Hexacopter_Multicopter_DJI-S800_on-air_credit_Alexander_Glinz

Tag Team: BMMRO, University of St Andrews (Scotland), Woods Hole Oceanographic Institution

Hexacopter: BMMRO, NOAA

Photo Credits: top two, moi (from BMMRO research vessel); remainder except for last, BMMRO; last, Wiki

WORLD OCEANS DAY 2016: “STASH THE TRASH”


View from a Skiff, the Marls, Abaco, Bahamas

WORLD OCEANS DAY 2016: “STASH THE TRASH”

Today the NOAA and other worldwide ocean guardian organisations are celebrating World Oceans Day. Looking at the websites and FB pages, one message is clear: People Are Rubbish. To put it another way, the global pollution of the oceans is caused solely by humans. The pristine seas and beaches of the world were unsullied until, say, the last 200 years. In 4 or 5 generations, all that has changed irreversibly.

Leave only Footprints - Delphi Beach, Abaco

My rather (= very) negative intro is counterbalanced by some more positive news: there are plenty of good guys out there working hard to make a difference to the rising tide of filth polluting the oceans. Clearing seas and beaches of plastic and other debris. Collecting tons and tons of abandoned fishing gear. Rescuing creatures trapped, entangled, injured and engulfed by marine debris and pollutants. Educating adults and – far more importantly – children and young people by actively involving them in their campaigns. Conducting research programmes. Lobbying and protesting. And a lot more besides.

A marine garbage patch: the sea creatures’ view (NOAA)Marine Garbage Patch from below (NOAA)

Abandoned fishing gear: a monk seal that was lucky; and a turtle that wasn’t (NOAA)Monk Seal in discarded fishing nets (NOAA)Sea turtle trapped in abandoned fishing gear (NOAA)

Four shearwaters killed by a cone trap. A fifth was rescued (NOAA)13138799_1188762361142231_1433873125345242619_n

The NOAA and sister organisations carry out massive programmes of clearance of marine debris, with working parties of volunteers who do what they can to deal with an intractable problem.Clearing Beach Debris (NOAA) Clearing Beach Debris (NOAA)

But you don’t need to be on an official working party for a large organisation. In the Bahamas and on Abaco, the BAHAMAS PLASTIC MOVEMENT, FRIENDS OF THE ENVIRONMENT  and BAHAMAS NATIONAL TRUST among others, do wonderful work on a more local level.
Childen collecting beach debris, Abaco (FotE)

HOPE  FOR  THE  FUTUREYoung conservationist on Abaco, Bahamas

Elsewhere, some tackle the problems caused by particular types of trash, balloons being an excellent example. I have posted before about BALLOONS BLOW, the brainchild of two sisters who learnt of the serious consequences to wildlife caused by mass balloon releases. Their work has been so effective that increasing numbers of mass releases are being cancelled in favour of other forms of celebration. A minus for balloon-makers of course, but a big plus for wildlife. The BB sisters also keep their own beach clear of the junk brought in on every tide.

Balloons Blow - Beach Debris (http://balloonsblow.org) Balloons Blow - Beach Debris (http://balloonsblow.org)

And on an individual basis, any old fool can make a tiny difference to a local beach. Here is one such doing just that…

A tangle of balloon strings on Delphi beachBalloon Strings, Delphi Beach (RH)

Guinea Schooner Bay: little visited, rarely cleaned. Plastic crap from a 10 foot radiusRH & trash, Guinea Schooner Bay

Credits: NOAA, FOTE Abaco, BPM, Balloons Blow, RH, Mrs RH

“TEACH YOUR CHILDREN WELL”: WHERE CONSERVATION BEGINS


Young conservationist on Abaco, Bahamas

“TEACH YOUR CHILDREN WELL”: WHERE CONSERVATION BEGINS

“Catch ’em young”. The perfect plan with children. On Abaco, wonderful work is continually being done with young children on the mainland and on each cay to teach them how precious their environment is, how fragile, and how important it is to take good care of it. The huge enthusiasm of the youngsters casts a beam of light onto the rather dark global picture of habitat destruction, pollution and ecological neglect that we have become depressingly accustomed too.

Young conservationists on Abaco

Education and training is carried out in schools; field work is done involving children of all ages; and camps are organised. FRIENDS OF THE ENVIRONMENT carries out this invaluable and rewarding task on an almost daily basis, offering students an astounding range of environment-based activities. Even the very youngest are catered for: the “Sea Beans Club”  is an after-school club for ages 3-5, which introduces young minds to their environment through educational activities and outdoor play.

Students and researchers from CWFNJ survey the beach to make sure that their activities will not disturb any plovers feeding in the areaYoung conservationists on Abaco

Students and volunteers selectively remove small invasive Casuarinas, which were encroaching on plover roosting habitat. By removing the invasive plants, native plants will be able to flourish and help stabilize the beach.Young conservationists on Abaco

The BAHAMAS NATIONAL TRUST, too, plays its part in educating children about the fascinating yet frail world around them. For example, Scott Johnson’s snake protection work, in which he demonstrates to small kids that Bahamas snakes are completely harmless and to be respected not feared, is a wonder to behold.

BNT’s Scott Johnson visits a school with his non-scary snakesScott Johnson - BNT - Bahamas Snakes - Children's Education

In addition there are strong partnerships with organisations many miles away from the Bahamas, of which the CONSERVE WILDLIFE FOUNDATION OF NJ is the prime example. Todd Pover, Stephanie Egger and the team take their remit beyond their well-known piping plover conservation work by engaging with the pupils of Abaco’s schools each year and inspiring them.

Amy Roberts Primary School CWFNJYoung conservationists on AbacoYoung conservationists on AbacoYoung conservationists on Abaco

Much of the work is done in the field, getting the children interested in birds, the shoreline, the vital ecological role of mangroves, and the problems of marine debris. Other important work can be done in the classroom.

Young conservationists on Abaco Young conservationists on Abaco(A quick shout-out to Tom Reed, who I know took the piping plover photo!)

The clear message being sent out to the schoolchildren on Abaco is this: you are never too young to learn how to appreciate, respect and look after your environment. And they are responding with intelligence and enthusiasm. We are lucky that these kids are the future.

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Stephanie Egger of CWFNJ writes: “This year, we’ve reached over 120 students through the Shorebird Sister School Network Program, both from the Bahamas and in the United States. We hope to foster a greater appreciation for wildlife, especially for the Piping Plover and its habitat, and inspire students to help now — and later on in their lives as adults — ensuring the recovery and survival of the bird for years to come”.

VOLUNTARY MUSICAL DIGRESSION

“Teach your Children” is the second track of Déja Vu, the 1970 CSNY album. Nash wrote it much earlier, when still with the Hollies, then stored it in his musical lumber room. Just as well: it fits perfectly with the rather fey hippy vibe of the rest of Déja Vu.

Young conservationist on Abaco

Credits: huge thanks for general use permission for material to FotE, BNT and CWFNJ; and to all the individual photographers concerned

BLUE CHROMIS: BAHAMAS REEF FISH (29)


Blue Chromis & Coral ©Melinda Riger @ GB Scuba

BLUE CHROMIS: BAHAMAS REEF FISH (29)

The little blue chromis Chromis cyanea will be instantly familiar to any snorkeler or scuba diver on the coral reefs of the Bahamas. These ever-present small fish – 6 inches long at most – are remarkable for their iridescent deep blue colour that flashes as they dart in and out of the coral and anemones of the reef.

Blue Chromis ©Melinda Riger @ G B Scuba

Although at first sight  this chromis species – one of many – looks blue all over, adults have a black dorsal stripe and black edging to their fins. They make colourful additions to aquariums, though to my mind they look far more attractive nosing about the reefs foraging for the zooplankton upon which they feed (see header image for details…)

Blue Chromis ©Melinda Riger @ GB Scuba

The blue chromis was the second fish species I encountered on my first ever reef dive, at Fowl Cay Marine Preserve with Kay Politano. The first fish was the endearingly inquisitive sergeant major with its smart black and yellow stripes which came right up to my googles to eyeball me. I loved that, even though my pitiful swimming technique meant that I had plenty of other distractions, not least remembering to breathe. Air, that is, rather than water.

Blue Chromis ©Melinda Riger @ GB Scuba

Chromis_cyanea_(blue_chromis)_(San_Salvador_Island,_Bahamas)

SO JUST HOW BIG ARE THESE FISH, COMPARED, SAY, TO A BLUE TANG?

Blue Tang with blue chromis in its wakeBlue Tang with Blue Chromis © Melinda Riger @GB Scuba copy

All photos Melinda Riger of Grand Bahama Scube, except the penultimate by James St John, taken in San Salvador