A study proposing a ban on spear guns and gill nets in the Great Barrier Reef is now being criticised by Australian scientists saying its results – which were obtained from Kenya and Papua New Guinea – aren’t relevant to the Great Barrier Reef.

The study, carried out by an international team of scientists led by Dr Josh Cinner from the ARC Centre of Excellence for Coral Reef Studies, proposed a ban on fishing gear such as spear guns, fish traps, beach seine nets, and gill nets to aid damaged reefs in their recovery. According to data obtained from the waters of Kenya and Papua New Guinea, certain types of fishing gear are more damaging to corals and to certain species of fish needed to help reefs recover from bleaching or storm damage.

“They [corals and certain types of reef fish] are already on the edge because of the overfishing and the additional impact caused by a bleaching even can push them over,” said Dr Cinner, who is based at James Cook University.

According to Dr Josh, spear guns are the most damaging of all fishing gear, particularly to fish that help maintaining the reef by removing seaweeds and sea urchins.

“Spear guns target a high proportion of species that help maintain the resilience of coral reefs, but also can result in a surprising amount of damage to the corals themselves,” Dr Cinner said. “When a fish is shot with a spear gun, it often hides in the reef, so some fishermen break the corals in their attempts to get it.”

Not applicable to the Great Barrier Reef, says other scientists Fellow JCU fisheries scientist Dr Andrew Tobin do not agree with the fishing gear ban recommendation, saying that the results from the study aren’t applicable to Australia’s Great Barrier Reef.

“Some of those findings are probably very reasonable for those areas they’ve studied, but to make any link to Great Barrier Reef waters is probably drawing a very long sword,” Dr Tobin said.

According to Townsville marine biologist Dr Walter Starck, who provides advice to Sunfish North  Queensland, herbivore fish aren’t being overfished in the Great Barrier Reef area.

“Here in Australia, it is completely irrelevant,” he said.

“Small fish may have small brains but they still have some surprising cognitive abilities”, says Dr Jeremy Kendal* from Durham University’s Anthropology Department.

Dr Kendal is the lead author of a new study showing that Nine-spined stickleback fish (Pungitius pungitius) can compare the behaviour of other sticklebacks with their own experience and make choices that lead to better food supplies.

“‘Hill-climbing’ strategies are widely seen in human society whereby advances in technology are down to people choosing the best technique through social learning and improving on it, resulting in cumulative culture”, says Dr Kendal. “But our results suggest brain size isn’t everything when it comes to the capacity for social learning.”

Around 270 Nine-spined sticklebacks were caught from Melton Brook in Leicester using dip nets. After being divided into three experimental groups and one control group, the fish were housed in different aquariums and the fish in the experimental groups were subjected to two different learning experiences and two preference tests in a tank with a feeder placed at each end.

1.) The fish were free to investigate both feeders during a number of training trials. One feeder (dubbed “rich feeder”) always handed out more worms than the other one (dubbed “poor feeder”). The fish were then tested to see which feeder they preferred.
2.) In the second training trail, those fish that come to prefer the rich feeder could see other fish feeding. During this stage, the rich and poor feeders were swapped around and the rich feeder either gave even more worms than before or roughly the same or less. During the second test, the fish were once again free to explore the tank and both feeders. Around 75 per cent of the Nine-spined sticklebacks had learned from watching the other fish that the rich feeder, previously experienced first hand themselves as the poor feeder, gave them more worms. In comparison, significantly fewer sticklebacks favoured the feeder that appeared to be rich from watching other sticklebacks if they themselves had experience that the alternative feeder would hand out roughly the same or more worms.

Further testing showed that the sticklebacks were more likely to copy the behaviour of fast feeding fish.

“Lots of animals observe more experienced peers and that way gain foraging skills, develop
food preferences, and learn how to evade predators”, Dr Kendal explained. “But it is not always a recipe for success to simply copy someone. Animals are often better off being selective about when and who they copy. These fish are obviously not at all closely related to humans, yet they have this human ability to only copy when the pay off is better than their own.”

The study, which has been published in the journal Behavioral Ecology, was carried out by scientists from St Andrews and Durham universities and funded by the Biotechnology and Biological Sciences Research Council. The lead author of the study, Dr Kendal, is a Research Council UK Fellow.

A moray eel species native to warm tropical waters have been caught in the considerably colder waters found off the coast of Cornwall, UK. (picture here)

After catching the 4 feet (120 cm) long fish, West Penwith fishermen brought it to the Newlyn Fish Market auction where it was purchased by fish dealer John Payne of Marisco Fish in Penzance.

”I thought it shouldn’t be there, realised it was rare and it shouldn’t be swimming in these waters so I decided to buy it. It is a one off and first of its kind found in these waters”, said Payne who plans to stuff the eel and keep it in his shop.

Rory Goodall of Cornwall Wildlife Trust has never heard of a tropical moray eel being caught this far north before. “They are not rare in the Mediterranean but I have never heard of them being seen here so it’s possible that they have never been caught in the British waters before”, he said.

Moray eel of the species Gymnothorax meleagris.
Copyright www.jjphoto.dk.

We often think of evolution as something extremely slow that takes place over the course of thousands or even millions of years. The truth is however that certain adaptations can occur very quickly, sometimes over the course of just a few generations.

Male Guppy. Copyright www.jjphoto.dk

Eight years later, a time period equivalent of less than 30 guppy generations, the guppies living in the low-predation environment had adapted to this environment by producing larger and fewer offspring with each reproductive cycle.

“High-predation females invest more resources into current reproduction because a high rate of mortality,
driven by predators, means these females may not get another chance to reproduce,” explained Gordon, who works in the lab of David Reznick, a professor of biology.

The guppies living below the barrier waterfall where there were a lot of predators did not show any signs of producing fewer or larger offspring.

“Low-predation females, on the other hand, produce larger embryos because the larger babies are more competitive in the resource-limited environments typical of low-predation sites”, Gordon said. “Moreover, low-predation females produce fewer embryos not only because they have larger embryos but also because they invest fewer resources in current reproduction.”

The paper will be published in the July issue of The American Naturalist.

Swanne Gordon’s research team included David Reznick and Michael Bryant of UCR; Michael Kinnison and Dylan Weese of the University of Maine, Orono; Katja Räsänen of the Swiss Federal Institute of Technology, Zurich, and the Swiss Federal Institute of Aquatic Science and Technology, Dübendorf; and Nathan Miller and Andrew Hendry of McGill University, Canada.

Financial support for the study was provided by the National Science Foundation, the Natural
and Engineering Research Council of Canada, the Le Fonds Québécois de la Recherche sur la Nature
et les Technologies, the Swedish Research Council, the Maine Agricultural and Forestry Experiment
Station, and McGill University.

A new species of wrasse living off the Brazilian coast has been described by Osmar Luiz, Jr, Carlos Ferreira and Luiz Rocha. The new species has been named Halichoeres sazimai after Brazilian ichthyologist Ivan Sazima from Universidade Estadual de Campinas in São Paolo.

Halichoeres sazimai inhabit the Western South Atlantic off the southern and south-eastern coasts of Brazil where researchers regularly saw it foraging solitary on sand bottoms immediately adjacent to the lower end of rocky reefs. Occasionally, harems consisting of 5-10 specimens were also spotted. The fish was sometimes observed over the reefs as well, but usually stayed at a dept of at least 20 metres. According to the researchers, this may have to do with a preference for water colder than 18° C.

Halichoeres sazimai separates itself from its close relatives by having a white body adorned with a zigzag patterned midline stripe which is yellow or golden in females and juveniles and black and brownish in terminal males.

Sorry i have not found a pic of this species.

The paper has been published in the journal Zootaxa.
“OJ, Jr, Luiz, CEL Ferreira and LA Rocha (2009) Halichoeres sazimai, a new species of wrasse (Perciformes: Labridae) from the Western South Atlantic. Zootaxa 2092, pp. 37–46.”

U.S. researchers John F. Switzer* and Robert M. Wood** have described a new species of darter from the Meramec River drainage of Missouri, USA. The new species has been named Etheostoma erythrozonum and is the first known fish species endemic to the Meramec River drainage. Its common name is Meramec Saddled Darter.

Etheostoma erythrozonum is a sister species of the Missouri Saddled Darter, Etheostoma tetrazonum, an inhabitant of the Gasconade River, Osage River, and Moreau River drainages. The Missouri Saddled Darter is one of several darter species endemic to the northern Ozark region of Missouri. When E. tetrazonum was first described, it was only known to exist in the

Osage and Gasconade River systems. However, within a year of its description, individuals of E. tetrazonum were identified from the Meramec River system, a tributary of the Mississippi River. Since then the distribution of E. tetrazonum has been considered to include the Meramec, Gasconade, Osage, and MoreauRiver systems.

In 1984, the first sign of E. tetrazonum actually being more than one species was found when an electrophoretic analysis unveiled considerable genetic divergence between populations of E. tetrazonum from the Meramec and Osage River drainages. This notion has now been supported by a recent molecular phylogenetic analysis of 13 populations of E. tetrazonum,

As a result, the specimens living in the Meramec River drainage have now been recognized as a separate species and the name E. tetrazonum will from now on only pertain to the specimens native to the Moreau, Osage, and Gasconade River drainages. As mentioned above, the Meramec River drainage species has been given the name Etheostoma erythrozonum.

E. erythrozonum is very similar to E. tetrazonum but without the prominent blue-green colouration. Some male E. erythrozonum darters do have a blue spinous dorsal fin base, but the blue colour is inconspicuous and never as outstanding as in E. tetrazon. (The anal fin of E. erythrozonum is also blue-green.)

Male E. erythrozonum darters sport a horizontal red-orange stripe that runs along the lower sides of the body from the pelvic fins to the anal fin with an irregular dorsal margin, while the male E. tetrazonum darter has a dorsal stripe with a well-defined dorsal margin in. Another notable difference between the two species is how E. erythrozonum has a series of irregularly shaped red-orange blotches instead of the well defined vertical bars seen on male E. tetrazonum darters.

The paper has been published here in the journal Zootaxa. Picture is Available in the online publication.

* John F. Switzer, U.S. Geological Survey, Leetown Science Center, Aquatic Ecology Branch, Kearneysville, West Virginia

E-mail: jswitzer@usgs.gov

** Robert M. Wood, Department of Biology, Saint Louis University, St. Louis, Missouri

E-mail: wood2@slu.edu

Brachypopomus gauderio is not the only electric knifefish recently described from South America, U.S. researchers John P. Sullivan* and Carl D. Hopkins** have described another member of the genus Brachyhypopomus and given it the name Brachyhypopomus bullocki.

This new species is named in honour of Theodore Holmes Bullock, a renowned neurobiologist who died in 2005. Bullock was a pioneer of the comparative neurobiology of both invertebrates and vertebrates and is credited with the first physiological recordings from an electroreceptor and for championing electric fishes as a model system in neurobiology. The electric organ discharge waveform of Brachyhypopomus bullocki is biphasic, 0.9–1.6 milliseconds in duration, and the pulse rate varies from 20–80 Hz.

Brachyhypopomus bullocki is found throughout the Orinoco Basin in Venezuela and
Colombia. It can also be encountered in the in the Rio Branco drainage of Guyana and the Roraima State of Brazil, as well as in the upper part of Rio Negro near the mouth of Rio Branco.

Brachyhypopomus bullocki appears to prefer clear, shallow, standing water in open savannah, or savannah mixed with stands of Mauritia palm. It has also been collected among plants growing along the banks of small pools fed by streams. In Rio Negro, a specimen was found amongst palm leaf litter near the outlet of a black water stream.

Brachyhypopomus bullocki distinguishes itself from its close relatives by having larger eyes (comparative to the head), a short abdomen, and distally enlarged poorly ossified third and fourth branchiostegal rays.

The paper can be downloaded from Cornell University.

* John P. Sullivan, Department of Ichthyology, The Academy of Natural Sciences, Philadelphia. Email: sullivan@ansp.org

** Carl D. Hopkins, Department of Neurobiology and Behavior, Cornell University, New York. Email: cdh8@cornell.edu

Brazilian ichthyologists Julia Giora and Luiz Malabarba have described a new species of electric knifefish and named it Brachypopomus gauderio.

The fish lives in the central, southern and coastal regions of the Rio Grande do Sul state in Brazil, as well as in Uruguay and Paraguay, and its name is derived from the word “gaúcho”, a local term denoting a person living in the countryside (pampas) of the Rio Grande do Sul state, southern Brazil, Uruguay and Argentina.

Brachypopomus gauderio inhabits river banks, slow-moving creeks, lagoons, and flooded areas with muddy or sandy bottoms and has only been found among surfacing or floating plants.

You can distinguish Brachypopomus gauderio from its close relatives by its yellow dorsal surface, and on the brown markings which form a reticulate pattern.

I have not been able to find a picture.

The description has been published in the journal Zootaxa.

”Giora, J and LR Malabarba (2009) Brachyhypopomus gauderio, new species, a new example of underestimated species diversity of electric fishes in the southern South America (Gymnotiformes: Hypopomidae). Zootaxa 2093, pp. 60–68.”

Several types of commonly used fish egg disinfectants increase the risk of swim bladder disorder in fish, a new study from Israel reveals.

In an effort to prevent fungal growth, many fish breeders use various chemicals, such as methylene blue, hydrogen peroxide, acriflavine and chloramine-T to aquariums where eggs are kept. This practise is especially common among breeders who will not let the parents stay with eggs and fry. Many fish species carry out parental care and eggs from such species often depend on one or both parents gently fanning fresh water over them and manually removing any unfertilized eggs from the batch. Without such parental care, the eggs easily succumb to fungi unless the fish breeder adds some type of fungicide to the water.

The new Israeli study, which focused on Angelfish (Pterophyllum scalare), revealed that some of these chemicals may be responsible for a swim bladder disorder in developing fish. In fish suffering from this type of disorder, the swim bladder can not inflate properly and the fry fails to develop into a fully free-swimming adult. Among aquarists, such fish are commonly known as “belly sliders” due to their peculiar way of moving around the fish tank.

Methylene blue

Eggs hatched in the presence of 1, 2 and 5 ppm methylene blue exhibited significant increases in swim bladder non-inflation (11%, 9% and 33%, respectively; none in controls).

Time of exposure to methylene blue was a key factor. Exposure for up to 1 day post-hatch did not affect swim bladder non-inflation, but exposure from 2 days onwards significantly increased swim bladder non-inflation.

Hydrogen peroxide

Hydrogen peroxide at 250 ppm significantly increased swim bladder non-inflation (65% comparing to 27% in the control). Higher concentrations resulted in 100% mortality.

Acriflavin

Exposure to acriflavin at 2.25 ppm, but not 1.25 ppm, significantly increased swim bladder non-inflation (75% and 52% respectively; 20% in controls).

Chloramin-T

Chloramine-T did not significantly affect swim bladder non-inflation.

For more information, see the paper “C. Sanabriaa, A. Diamantb and D. Zilberga (2009) – Effects of commonly used disinfectants and temperature on swim bladder non-inflation in freshwater angelfish, Pterophyllum scalare (Lichtenstein)”. The paper has been published in the journal Aquaculture.

In several species of fish, such as the cichlid species Neolamprologus pulcher, it is common for subordinate females to help an unrelated dominant breeding pair raise their young. The reason behind this seemingly altruistic behaviour, known as alloparental care, has puzzled scientists for many years and one of the most widely spread hypotheses put forward has been the ‘pay-to-stay’ hypothesis. According to the ‘pay-to-stay’ rationale, the subordinate female helps out the dominant pair just to be able to stay in the group. Not being ostracised from the group augments her long-term survival chances, thus increasing the chance for her to live long enough to eventually obtain a breeding position.

Picture by: JJPhoto.dk

A new study carried out by Dik Heg and coauthors does however bring forth a new hypothesis: the substrate rationale. In their study, Heg and his colleges tested the hypothesis that subordinate female cichlids are helping dominant pairs in return for a more immediate direct reproductive benefit. After a series of experiments where the total number of eggs produced over a 30 day period by dominant and subordinate Neolamprologus pulcher females were carefully counted, researchers found that a subordinate female helping out a dominant pair was more likely to produce eggs herself compared to other subordinate females.

According to Heg and coauthors, the most likely reason for the increased reproductive success of “fish nannies” is that the subordinate female gains access to the breeding substrate.

If you wish to read more, see the paper “Heg, D, E Jutzeler, JS Mitchell and IM Hamilton (2009) Helpful female subordinate cichlids are more likely to reproduce”. It has been published in the journal PLoS ONE.

Here at AC Tropical Fish, we believe in the Jude Law-hypothesis. The dominant female will naturally snatch away the most prosperous male, but by posing as a benevolent nanny even a subordinate female can gain access to his home and hope for some of his triumphant DNA to eventually find its way into the genetic make up of her own offspring.