Conservation – Page 38 – Shark Research & Conservation Program (SRC)

Ocean Acidification and Your Dinner: Impacts of Marine Seafood

January 21, 2013/0 Comments/in Conservation /by aanstett

By Emily Rose Nelson
RJD Intern

Ocean acidification is a term commonly used in the world of marine science. This process can most easily be described as the lowering of oceanic pH due to increased atmospheric carbon dioxide concentrations. However, there is much more to this complicated process, which could mean great changes for the future of our oceans.

It is no surprise that atmospheric carbon dioxide levels are increasing. Since the industrial revolution atmospheric CO2 concentrations have increased from 280 ppm to 396 ppm, and this number is expected to increase to 800 ppm by the year 2100. Unfortunately, much of this excess CO2 finds its way to the ocean, changing the natural chemistry of the water. When atmospheric CO2 is added to seawater a series of chemical reactions naturally occurs. The addition of excess CO2 shifts the equilibrium of this reaction series, resulting in increased hydrogen and lower carbonate concentrations. Because pH is equal to –log [H+] increased H+ concentrations have lowered the pH from pre-industrial 8.2 to a 7.8 (projected 2100). Carbonate is essential for calcifying organisms such as mussels, shrimp, some coral species, and more. Carbonate ions combine with calcium ions naturally found in seawater to form CaCO3, the skeletal material for many organisms. Lowered carbonate concentrations make it more difficult to form this compound, thus more difficult to calcify, and in some cases survive.

The effects of human population density on coral reef fish

January 14, 2013/0 Comments/in Conservation, Ocean News /by aanstett

By Brittany Bartlett, RJD Intern

Coral reef fisheries are extremely important to the livelihoods of millions of people. Unfortunately, habitat degradation and unsustainable fishing practices have resulted in a decline in these fisheries. Therefore, a recently published article by T.D Brewer et al. entitled “Effects of Human Population Density and Proximity to Markets on Coral Reef Fishes Vulnerable to Extinction by Fishing” seeks to understand the social and economic issues behind this depletion in order to improve management.

The Top 10 RJD Science and Outreach Accomplishments of 2012

December 28, 2012/1 Comment/in Conservation /by aanstett

2012 was a great year for the RJ Dunlap Marine Conservation Program. As it comes to a close, we wanted to share our top 10 science and outreach accomplishments from the past year with you.

10) In December, the RJ Dunlap Marine Conservation Progam’s Facebook Fan Page passed 1,500 fans! Have you become a fan yet? We use the page to share live updates and photos from the field, as well as to share marine science and conservation news from around the world. Like us on Facebook, and, while you’re at it, follow us on twitter, too!

9) We deployed 24 satellite tags in 2012, 8 on bull sharks, 2 on great hammerhead sharks, and the rest on tiger sharks. We also added a new type of satellite tag called a “HammerTag” to our toolbox. The custom-made tag has the ability to recharge its battery via a small solar panel, permitting multi-year deployments You can track all of our satellite tagged sharks from our website.

A tiger shark with a new HammerTag. Photo credit: Jim Abernathy

Drugs from the deep: Ocean bioprospecting

December 14, 2012/0 Comments/in Conservation /by aanstett

By Emily Rose Nelson, RJD Intern

Oceans cover over 70% of the earth’s surface. Some of the greatest biological diversity in the world is found in the seas. Over 200,000 species of invertebrates and algae have been identified, and this number is estimated to be only a small fraction of what is yet to be discovered. This immense biodiversity yields great chemical diversity. When working with potential pharmaceuticals this becomes extremely important, more chemically diverse substances are more suitable. The field of marine natural products is just over 40 years old and already over 15,000 chemical compounds have been identified as having biological function.

Many of these chemicals have cancer fighting potential. Many sessile organisms emit chemicals to prevent others from evading their space. Often times these chemicals are used to slow and prevent cell growth of surrounding sponges, etc. It is believed that the same chemicals these organisms let out when competing for space can be used to stop the uncontrolled division of cancer cells. Cancer treatment compounds have advanced quite a bit due to funding from the National Cancer Institute. Discodermolide is a polypeptide isolated from deep water sponges (Discodermia). This substance stops the reproduction of cancer cells by disrupting the microtubule network (partially responsible for movement of cells). Bryostatin, a substance released by some bryozoans, is believed to be particularly useful against leukemia and melanoma. The Caribbean mangrove tunicate produces a compound (Ecteinascidin-743 or ET-743) that has been tested in humans for the treatment of breast and ovarian cancers and found to be effective.

Longlining: A destructive fishing technique

December 12, 2012/0 Comments/in Conservation /by aanstett

by Megan Piechowski, RJD Intern

There is widespread knowledge and documentation of the problems shark species face in commercial fishing industries such as shark finning and longlining. Longlining is a fishing practice that uses a main line that is dozens of miles long with thousands of hooks deployed along the line. Along with the plights of these sharks lies many other affected marine species. For instance, along with the targeted pelagic fish, many marine birds and sea turtles are equally attracted to the baited hooks of longlines. This has caused a large estimated drop in the populations of seabirds and sea turtles, as the majority of this by-catch and fatalities goes undocumented. Groups of researchers have studied visual capabilities of sea turtles to understand whether different equipment designs can result in a decrease in unnecessary deaths that this fishing method produces. Many seabirds find their prey, small baitfish, in the ocean’s surface waters by diving headfirst towards their target. This hunting method has made many species especially vulnerable to longlining fishing methods.

This image represents the different parts and placements of the parts of a longline setup (Dietrich, Cornish, Rivera, Conant).

The albatross family of marine birds is especially susceptible to the decline in population size as they drown once hooked to the line. Due to the low number of natural predators to these birds, they have evolved to produce very few young throughout their lives. This is problematic when an estimated 7000 albatrosses (within two species of albatross) were killed in a single year in the 90’s (Stevens). It is in the best interest of both the fishing industry and the conservational biologists to limit the by-catch on these lines. The fishermen would have an increased catch of their targeted fish if more hooks were available without a sea turtle or marine bird attached. Likewise, conservational biologists are interested in protecting their specific species through technological improvements and fishing method modifications.

Scientists Fritsches and Warrant focused on the biological differences found between sea turtles species and pelagic fish species to determine if fishing gear could be modified to deter sea turtles. Due to hatchling sea turtle’s abilities to follow a light source, several experiments were conducted to determine the capabilities of the vision of these turtles. It was determined that tuna and billfish eye lenses block ultraviolet light, while green turtles’ eye lenses transmitted this wavelength of light (Fritsches, Warrant).

This graph supports the idea that hatchling sea turtles are able to sea UV light. The red dots represent the sea turtle’s orientation with the UV light, while the green dots represent their orientation without the UV light (Fritsches, Warrant).

Another measure of sea turtle vision used was the flicker fusion frequency, which measures an animal’s speed of vision. They found that marine animals that live mainly in the well lit surface waters (mahi mahi or green turtles) have “retinas that are capable of responding to light flickering with a frequency of 60 Hz” (Fritsches, Warrant). In contrast, animals that frequently dive to great depths (swordfish and leatherback sea turtles) “do not perceive the light as flashing because their retina is not capable of resolving such fast motion” (Fritsches, Warrant). This information suggests that different types of fishing lures attract different animals. Surface turtles, like the green turtle, are highly responsive to flashing light whereas diving sea turtles, like the leatherback, would be much less responsive to this input. The difference in diving behavior could provide a large consequence in vision between species of sea turtles (Crognale, Eckert, Levenson).

Before utilizing conservational management of fishing industries, an estimated 1,500 sea turtles were caught as by-catch per year (Dietrich, Cornish, Rivera, Conant). These researchers have compiled information that suggests that through implementing marine conservation techniques into management plans that the amount of sea turtles caught as by-catch has decreased by nearly 100 turtles a year (Dietrich, Cornish, Rivera, Conant). Seabirds are much more difficult to monitor as there are no official catch values reported by fisheries. The estimated yearly by-catch amount ranges widely from 100,000 to at least 500,000. In addition to the lack of observation in these fishing industries is a lack of reporting from fishermen, as a seabird species type is needed for a proper global catch estimate (Dietrich, Cornish, Rivera, Conant).

While it is easy for those who are passionate about shark conservation to become lost in a singular issue, it is important to remember that many marine species are facing severe population declines from similarly unsustainable fishing practices. It is unlikely for longlining to be stopped internationally, but it is possible to call for a change in deployment methods or gear type to decrease the by-catch rate of endangered seabirds and sea turtles. The large overlap in diet between marine animals has created a system of highly efficient removal of targeted (and also declining) pelagic fish and severe removal rates of other endangered marine animals that unknowingly hunt baited hooks and are killed. The decline in these predatory species creates a damaging impact on the health of the ecosystem, which is critical to monitor.

REFERENCES

Crognale, Eckert, Levenson. December 2006. The Sensory Biology of Sea Turtles: What Can They See, and How This Helps to Avoid Fishing Gear? U.S. Dep. Commer., NOAA Technical Memorandum NMFS-PIFSC-7

Dietrich, Kimberly S., Victoria R. Cornish, Kim S. Rivera, and Therese A. Conant. Best Practices for the Collection of Longline Data to Facilitate Research and Analysis to Reduce Bycatch of Protected Species. Rep. N.p., n.d. Web. 23 Nov. 2012. <http://www.nmfs.noaa.gov/pr/pdfs/interactions/longline%5fbycatch.pdf>.

Fritsches, Warrant. December 2006. Differences in the Visual Capabilities of Sea Turtles and Water Fisehs – Implications for Bycatch Reduction. U.S. Dep. Commer., NOAA Technical Memorandum NMFS-PIFSC-7

Stevens, William K. “Long Line Fishing Seen as Damaging To Some Fish and to the Albatross.” The New York Times. The New York Times, 05 Nov. 1996. Web. 23 Nov. 2012. <http://www.nytimes.com/1996/11/05/science/long-line-fishing-seen-as-damaging-to-some-fish-and-to-the-albatross.html?pagewanted=all>.

Conservation of the Critically Endangered Hawaiian Monk Seals

December 10, 2012/0 Comments/in Conservation /by aanstett

by Laurel Zaima, RJD Intern

Education is always the first step towards the conservation and recovery of a species. The endangered species list intends to bring awareness and education to the public about species that are on the brink of extinction. There are several different classifications that explain the population status of species: least concern, near threatened, vulnerable, endangered, critically endangered, extinct in the wild, and extinct (Monachus Schauinslandi). One of the most primitive of all living phocid species, the Hawaiian Monk Seal, is categorized as critically endangered. In the mid-19^th century, hunters targeted the Hawaiian Monk Seals for their precious skins and oils. The Monk Seal populations were hit so hard that they have yet to make a significant recovery. However, it is still possible for the Hawaiian Monk Seal populations to bounce back if the public is informed about the importance of conserving this species and the methods of successful conservation.

One of the reasons that hunters were capable of killing a significant amount of the Hawaiian Monk Seals in the 19^th century was due to the seals’ behaviors and their small habitat range. The Hawaiian Monk Seals are an endemic species to the Hawaiian Islands, which means they are native to this chain of islands and they are found no where else on earth (Protected Resources Division). Their small range of habitat made them an easy target for hunters. Although Monk Seals can travel hundreds of miles into the open ocean, they are not migratory mammals and have a habit of frequenting the same beaches over and over (Protected Resources Division). They also are usually found sleeping on the Hawaiian Island Beaches or in underwater caves, sometimes for days at a time (Protected Resources Division).

The positive impacts of reef balls

December 7, 2012/1 Comment/in Conservation /by aanstett

By Jon Dorsey, RJD Intern

It is evident that the ocean’s conditions are changing at alarming rates due to natural disasters and man’s activities. Pressures such as global warming, hurricanes and boat groundings all increase the environmental and physical stresses on delicate coral reefs. As a consequence of these increases pressured, coral reefs are rapidly reducing in size. After witnessing the destruction of the corals reefs off Grand Cayman after a hurricane passed through, Todd Barber founded the Reef Ball Foundation in 1993. Originally this foundation was focused on building these structures solely for coral reef restoration, but their innovative design has opened doors to many other types of restoration projects such as oyster reefs, mangrove plantings, and even beach erosion control.

Crown of thorns starfish: a threat to coral reefs

December 7, 2012/2 Comments/in Conservation /by aanstett

by Brittany Bartlett, RJD intern

Coral reefs are vulnerable species, highly susceptible to a wide range of disturbances. And, episodic outbreaks of the Crown-of Thorns coral killing sea star (Acanthaster planci) are one of these dangerous disturbances. These sea star outbreaks threaten the well being of our ocean, as they feed on and deplete reef building coral, altering the current composition of the marine ecosystem.

Until recently the causes and spatio-temporal dynamics of these sea star outbreaks have not been well understood. A recent study by Mohsen Kayal et al (2012) in the south Pacific, however, has been able to examine and describe the entire development and process of the outbreak, as well as the consequences that these epidemics have on benthic communities and resident coral feeding fish.

Harmful algal blooms

November 6, 2012/1 Comment/in Conservation /by aanstett

by James Komisarjevsky, RJD intern

Harmful Algal Blooms (HABs) are something that affects almost every coastal region in the world. Many people know of the these HABs as red tides (Figure 1). These HABs not only affect coastal regions but have also been found to affect open ocean, brackish ecosystems, and freshwater ecosystems. Most of these HABs have been found to be caused by blooms of microscopic algae or by blooms of phytoplankton.

Figure 1. This figure depicts a red tide caused by an algal bloom. (Source: Erin Watson, University of Tasmania)

There has recently been an increase in the number of HABs due to an increase in a waters nutrient supply. An increase of nutrients such as nitrogen, phosphorous, silicate, and micronutrients can lead to a HAB. There is a concern today for the relationship between HABs and the increase of nutrient supply (eutrophication). Humans are a big component of the increase of nutrients because of sewage, groundwater and atmospheric inputs, and agriculture and aquaculture runoffs. When compared to preindustrial and preagriculture times, it has been estimated that phosphorous levels have increased three times in the world’s oceans. An example of this can be seen in China where there have been major changes in the quality of its coastal waters. Due to Chinas increasing populations and its rise in agriculture, there has been a fourfold increase of nitrate concentrations and a 30% increase of phosphate concentration in the past 40 years at the mouth of the Changjian River. The increase of nutrients due to humans has led to a significantly higher algal biomass and also a change in the phytoplankton community.A HAB is considered to be a concept rather than a scientific definition. There are certain criteria, which if met, an event is considered to be a HAB. The criteria contains causing injury to human health, causing socioeconomic interest, or changes certain components of an ecosystem. These HABs can cause illness or the deaths of marine organisms by the transfer of toxins through the food web (bioaccumulation). They can also cause an injury to human health due to the consumption of seafood which contain these toxins.

Climate change and overfishing have also caused concern for the increase of HABs. Prediction of the effects of climate change can only be speculated. This is because there is little long-term data of algal blooms for a specific region. Generally, at least 30 years of data is needed to establish trends on HABs. It is thought that some harmful species of algal blooms may become more prevalent while others may be negatively affected. Climate change will pose challenges for scientist because it is likely to cause changes in species composition, abundance, and the timing of HABS.

In recent years there has been an increase in the study ecogenomics and HAB species genes in order to further study HABs. Ecogenomics have caused interest because it gives scientist a way to study HABs and its surrounding ecosystem. This will allow for further information to be discovered about the consequences of HABs ecologically and their affect on other species evolutionarily. Also studying the genetics of HAB species will help scientist locate which genes are responsible for certain toxin production. This will help to classify the different species, which contain or do not contain the genes responsible for toxin production.

There is an increasing demand for the study of HABs and the species which cause them. Due to the anthropogenic affects such as eutrophication and overfishing, an increase in the number of HABs can have many affects on humans. Further and more studies of HABs will hopefully provide insight into helping us lower the numbers of HABs in the future.

REFERENCES

Anderson, Donald M., Allan D. Cembella, and Gustaaf M. Hallegraeff. “Progress in Understanding Harmful Algal Blooms: Paradigm Shifts and New Technologies for Research, Monitoring, and Management.” Annual Review of Marine Science 4 (2012): 143-76. Print.

Assessing Management Efforts for Large Whales

October 30, 2012/0 Comments/in Conservation /by aanstett

by Fiona Graham, RJD Intern

Sometimes imposing a regulatory action alone is not enough. Implementing a new policy aimed at reducing the mortality of a species or group of species requires scientific studies to gather the information necessary to enact that policy. Some important questions to be asked are which species need protecting? Where are they most vulnerable, both spatially and temporally within their life cycle? What threats are they faced with? Once a clear idea of how and why a species needs protected is formed, regulations can be put into place using that information to conserve that species. While this may be a great start, following up with an assessment of the management that has been put into place can be just as important. Maximum effectiveness depends upon strong science from beginning to end.

A recent study by Julie Van Der Hoop and colleagues provides one such assessment of management attempting to mitigate human induced mortalities of large whales in the Northwest Atlantic. To do this, the team complied reports of strandings, mortalities and necropsies from 1970 to 2009 for 8 species of large whales, and determined temporal and spatial trends. They found that 66.9% of mortalities were related to human activities, and that the leading cause of death was entanglement in fishing gear.