The "Hoodwinker"

The Hoodwinker is a new species of sunfish that has been discovered in an interesting way. Sunfish are the largest heaviest known bony fish in the world. Adult fish can weigh anywhere from 250 to 1000 kg reaching lengths of 11 feet long. Sunfish are uniquely known for the back fin they are born with that never grows. This fin instead folds into its self as the fish grows creating a clavus or a rounded rubber for the species.

Sunfish can be found frequently in tropical and temperate waters in the oceans of the world. Spending their time in deep waters scavenging for jellyfish is their main prey consumption. They also eat smaller fish and a large number of zooplankton. The teeth of a sunfish are somewhat fused together causing a beak like structure. The fish is not able to  fully close their mouth.

Sunfish may also spend their time near surface waters taking in the sunlight. When near the surface, sunfish are commonly mistaken for sharks when their dorsal fins are above the water. As well as coming to the surface to sunbath, sunfish come to the surface to deal with the parasites infested in their skin. The sunfish take advantage of the feeder fish at the surface to remove the parasites. Seagulls will also scrap the parasites off the fish while they lay on their side close to the surface of the water. 

The Hoodwinker species was discovered before it was spotted. Researchers were analyzing large numbers of DNA samples from sunfish. The genetic sequencing showed that there were four separate species but only three of the species were known: Masturus lanceolatus, Mola mola, Mola ramsayi, and the unidentified DNA. The hunt for finding the new species then began. 

The hunt for the new species was not an easy task for the fact that all sunfish species look similar. The researchers started their hunt differently by looking on social media for  different photos of sunfish that have been posted and seeing if they're any identifications in photos of a different species. Observers from Australia and New Zealand caught a sunfish within a net receiving a photo and a genetic sample to give the researchers. 

The photo of this fish had a small structure on the back fin that was never spotted before on other sunfish. Later on at the same beach there were four sunfish stranded. The research team was notified of the fish and was on their way to the site to observer the stranded fish. The fish on the island turned out to be exactly what the researchers had been looking for, the hoodwinker, matching the DNA of the unknown within the lab.  The Hoodwinker was then properly named the Mola teca, for the species that was hiding in plain have site for many years.

Figure: Hoodwinker Sunfish found stranded

Hookwinker, Mola teca, are not known to grow bumps on their body, instead their body sizes stay around the same from juveniles to adults. Another distinctive factor is that their back fins are separated into two half's by a small piece of skin, into an upper and lower half. The Hoodwinker is mostly known to be found in colder waters. Not a tremendous amount of details of the species is known for the fact the sunfish are found in an area that is hard to reach by humans.

Murdoch University ( 2017). The four-year treasure hunt for the hoodwinker sunfish. Retrieved from           5https://theconversation.com/the-four-year-treasure-hunt-for-the-hoodwinker-sunfish-81265

National Geographic (2018). Ocean Sunfish. Retrieved from
         https://www.nationalgeographic.com/animals/fish/o/ocean-sunfish/

Pistol Shrimp's Bizarre Method of Protection

If you find yourself under the coastal tropical waters you may just hear what sounds like a popping noise. Originally these sounds were thought to be the jaws of shrimps closing, it actually turned out to be something different. A species of shrimp called the pistol shrimp are actually what are making these sounds. They can be rather loud as well, louder than a .22 caliber rifle, this would be the second loudest noise in the ocean next to sperm whale clicks.

Pistol Shrimp

 A group of marine scientists wanted to figure out the details of these shrimp and their gunshot-like noises. It turns out that the shrimp is forcing out still water from in-between their claws and that creates a vortex-like motion. This swirling vortex that comes from the claw creates a void in the center and as it travels that void will collapse. The whole process happens in just a short time, less than half a millisecond to be more precise, but the vortex can travel as fast as thirty meters per second. One researcher said that you wouldn’t want to stick your hand in a tank with one because the force does hurt rather badly.



These shrimps are only known to grow to about five centimeters in size so they’re gunshot vortex is only useful against other individuals with a similar size. They don’t use this technique to stun prey or anything in that manner. This is due to the fact that these shrimps are scavengers that feed mostly on what they can find laying on the ocean floor. They typically are known to do this if they are trying to protect a mate or their homes. When two pistol shrimps duel it out these shockwaves aren’t fatal to them, but it will leave some puncture wounds and can even tear off a claw. These tiny underwater gunfights can still cause some potential damage.

 References:

Woodward, A. (2017, October 27). How a tiny shrimp fires a savage shock wave using just its claw. Retrieved January 28, 2018, from https://www.newscientist.com/article/2151700-how-a-tiny-shrimp-fires-a-savage-shock-wave-using-just-its-claw/

Blue Sharks: Bioindicators of Pollution and Health in the Atlantic Ocean

Pollution is becoming an ever-prevalent problem for marine ecosystems. Many of these ecosystems are being affected by contaminants produced from human activities. Pollutants can cause harmful effects at lower levels of biological organization, such as the organism level or at the gene and cellular level. In this study, these effects were examined in blue sharks (Prionace glauca).

Blue Shark (P. glauca) 

Blue sharks are one of the more common species of shark consumed by humans. They are also apex predators, meaning they are at the top of the food web. These components make them a prevalent species to study as it allows for examination of bioaccumulation, as well as the effect it could potentially have on humans. This particular study aimed to measure if Atlantic blue sharks have high levels of POPs and metals in their tissues that could effect human health as well. The contaminant body burden levels correlated with biochemical responses of stress in the organism were measured as well.

Twenty blue sharks (12 female and 8 males) were captured at a depth of approximately 20 meters in the Atlantic Ocean, southwest of Portugal. All individuals caught were considered to be juvenile sharks. After capture, liver, muscle, and brain tissue were collected for analysis. After preparation of these tissues, statistical analysis was done to determine the amount of contamination present.

Marine apex predators, such as blue sharks, tend to accumulate pollutants and contaminants in their bodies at higher levels that the majority of other animals in their food chain. When examining the tissues from this sample of blue sharks it was found that the liver tissue contained higher levels of persistent organic pollutants (POPs) than the muscle tissue did. This was to be expected as POPs typically accumulate in tissues that have higher lipid content, such as the liver. POP analysis also revealed that non dioxin-like polychlorinated biphenyls (NDL-PCBs) were the most abundant contaminant present in blue sharks. NDL-PCBs have been shown to produce toxic effects, and can affect fish behavioral responses. Some of the blue sharks sampled even had levels of NDL-PCBs present higher than what is legally allowed for human consumption. In addition to NDL-PCBs, brominated flame retardants (BFRs) were also found to be at high levels in these blue sharks captured from the Atlantic Ocean. BFRs have also been shown to have dangerous consequences to both marine organisms and humans, as they can impair organs such as the brain or thyroid.

Figure 1: Amounts of POPs found in liver and muscle tissue

Even more significant, as stated earlier, is the fact that all individuals were juveniles. Bioaccumulation has been proven to increase with size and age, so it is estimated that these already high levels of bioaccumulation of dangerous contaminants would have only continued to increase if the juveniles would have grown to full adult size.

Also examined in this study was the bioaccumulation of metals. In contrast to POPs, metals had higher levels of bioaccumulation in muscle tissue than liver tissue. These specimens showed higher levels of Mn, Cd, Fe, and Cu. However, in a previous study done approximately two decades ago that contained bigger organisms, showed lower levels of these contaminant burdens. This result raises red flags as it could indicate the possibility of a historical increase of contamination of these Atlantic Ocean waters. Mercury levels were also found to be above safe consumption levels. This is again troublesome as these blue sharks were juvenile and mercury levels are known to only increase as the size of the organism increases.

Because marine animals are constantly surrounded by xenobiotics, physiological alterations in response to stress could potentially be induced. When a Canonical Correspondence Analysis (CCA) plot was conducted of the liver tissue, it was discovered that nearly all contaminants had a positive association with DNA damage, which seems to indicate that when these blue sharks are exposed to POPs and metals, they are not able to counter the effects of the radical oxygen species (ROS) produced and prevent DNA damage.

Figure 2: CCA of liver tissue

It was concluded the lipid peroxidase (LPO), DNA damage, and inhibition of the enzyme glutathione peroxidase (GPx) were the main effects due to exposure to POPs and metals, which indicates they may be the best options to use for future biomonitoring. These contaminants can lead to ecological damage as well in terms of the blue sharks’ swimming, feeding, and reproduction habits. This conclusion can be seen and summarized in the figure below.

Figure 3: Blue sharks as bioindicators

This study also shows the prevalence of bioaccumulation and the potential human health risk it could have as blue sharks are a common species of sharks that are consumed by humans. In future studies, it would be beneficial to examine the individuals' stomach contents as well to see how feeding habits may influence bioaccumulation. It would also be important to examine larger sampling areas in the Atlantic Ocean as well as other oceans to see how contamination and pollution affect populations there as well.

Alves, L., Margarida, N., Marchand, P., Bizec, B., Mendes, S., Correia, J, Lemos, M., & Novais, S. (2016). Blue sharks (Prionace glauca) as bioindicators of pollution and health in the Atlantic Ocean: Contamination levels and biochemical stress response. Science of Total Environment, 563-564, 282-292.

Largest Sea Turtle Population changing due to Environmental Warming

Sea Turtles have temperature-dependent sex determination. Meaning that the sex of the hatchlings are determined by the incubation temperature during embryonic development. The critical point of development, the thermosensitive period, is during the middle of the third period in incubation. The pivotal temperature is the point at which half of each gender is hatched; while colder temperatures produce more males, warmer temperatures will produce more females.

The transitional range is based around the pivotal temperature, to where all males or females will be hatched. The pivotal temperature only differs by a few degrees ether way to produce all of one gender in the hatch. With global warming causing temperatures to rise above the pivotal point more females are being hatched. The climate change is also causing the mortality rate of the hatchlings to rise.

In Australia there are two breeding populations of turtles the Southern Great Barrier Reef stock (sGBR) as well as the northern Great Barrier Reef stock (nGBR). Turtles mate along the area of their nesting beaches. Females can lay multiple clutches of eggs each with around 100 eggs. Each clutch that is laid is incubated around 55 days. These hatchlings make their way into the open ocean and stay there till they reach the age of sexual maturity, around 25. At this time in their life they return to the same beach they were hatched at to mate.

Figure 1: Nesting Areas

The northern Great Barrier Reef population is one of the largest green sea turtle populations in the world. The figure above shows the area of Australia where the two populations nesting sites. The population is estimated to have around 200,000 females nesting. The population has shown that there is an increase of nesting females despite the fact that there was a signs of declining population in the 1990's. Research has been completed on this population of turtles to better understand the way the climate changes affect the gender and growth of the population.

To test this effect the best approach would be to estimate the exact number of males and females that are being hatched during nesting season. The issue with recording this data is you are unable to see the sex of a turtle upon hatching. Researchers are able to determine the sex of the hatchlings by histological examining the gonads. However, this would mean sacrificing the hatchling's life which would go against the point of the research of studying the population’s growth, not to mention the ethical issue as well. There are tests though that can be run on the dead hatchlings found left over in the nest.

There is a foraging ground that is also labeled in figured one, Howick group of island. Genetic testing and tagging that have been completed show if the turtles are from the nGBR or the sGBR, they age and gender. At this area researchers tested turtles laparoscopic to determine the gender and genetics of the sexually immature turtles at the feeding ground. Also data was taken from three age ranges. The results show that all ages of the turtles were found to be mostly female.  

Figure 2: Data of Howick Islands

Another point of the analysis was to estimate the temperature of the sand over the years that these turtles would have been incubated in. There was no recorded numbers for the sand over the years but there was recorded temperatures of the air and sea surface. These numbers were used to find around what temperature the sand would have been at the time. Figure 3 shows the estimated temperatures based around 0 the pivotal temperature. The majority of the graph shows that the temperature would have been above the pivotal point. The information of the estimated sand temperature correlates to the data in figure 2, showing that mostly would have been hatched in previous years. 

Figure 3: estimated sand temperatures

The researchers are noticing the number of females increasing every year with the temperatures being above the pivotal point. The large number of females is concerning for the future of the turtle population. There is no way to tell for sure how many males are needed to sustain the population and/or to keep the same large numbers present. With the females continuing to outnumber the males in the population there will be less sperm to repopulate. The lacking number of males has already decreased the population’s number but the concern is if this trend continues the population will reach extinction over time. The sea turtles may have the ability to adapt to the climate change but these adaptations will take time to occur. While the rate of global warming is happening much faster than the progression of the adaptation. The idea for solving this problem is to slow down global warming and help the preserve the turtle population as best as possible.

Jensen, M., Allen, C., Eguchi, T., Bell, I., LasCasella, E., Hilton, W., Hof, C., & Dutton. P. (2018).
            Environmental Warming and Feminizarion. Retrieved from
            https://www.sciencedirect.com/science/article/pii/S0960982217315397?via%3Dihub

NOAA. (2017). What Causes Sea Turtles to be Male or Female? Retrieved from
            https://oceanservice.noaa.gov/facts/temperature-dependent.html