Fish Aggregating Devices: Ecological Problems with a Common Fishing Technique

by Tom Tascone, RJD Intern

If you’ve seen the television show “Wicked Tuna” on National Geographic, then you are certainly familiar with some of the techniques associated with long line fishing of these species.  While this is the method of choice for recreational fishermen, commercial fishermen seeking various species of tropical tuna have abandoned the traditional “rod-and-reel” technique for a far more effective tool.  Known as the Fish Aggregating Device (FAD), this tool relies on the natural behavior of tuna to congregate under floating objects on the surface of the ocean.  Most FADs are made from bamboo rafts in order to mimic natural logs and other marine debris that often drift out at sea, and large numbers have been deployed. Besides dramatically increasing the number of tuna caught in fisheries operations, how have the use of FADs modified the “floating object environment” in the ocean, and what effects can they have on marine ecosystems? A recent article published by Dr. Laurent Dagorn has attempted to answer these important questions.

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Anthropogenic Noise Pollution and Cetaceans

Brittany Bartlett, RJD Intern

It is no secret that our oceans and the species within them face a wide range of anthropogenic, human induced threats. And, as a result, the health of the ocean is rapidly declining. Among these threats is that of pollution; plastics, oil, runoff, etc. One form of pollution that tends to be overlooked is noise pollution, specifically the use of Navy Sonar.

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Seismic airguns: A threat to our oceans

by Zackery Good, RJD Intern

As the third anniversary of the Deepwater Horizon oil spill approaches on April 20th it is important to look at the lessons learned as well as the current state of offshore drilling.  The Deepwater Horizon spill released over four million barrels of oil into the Gulf of Mexico before finally being capped after 84 days (Camilli et al. 2010, Crone and Tolstoy 2010) .

Figure 1.  NASA satellite image of oil slick from Deepwater Horizon spill May 24, 2010 (Wikimedia Commons)

Figure 1. NASA satellite image of oil slick from Deepwater Horizon spill May 24, 2010 (Wikimedia Commons)

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Cruise Ship Pollution

by Dani Escontrela, RJD Intern

On a regular basis I am at Port Everglades which is one of the biggest cruise ships ports in the world and on any given day can house six or seven cruise ships, if not more. Every Saturday and Sunday the Oasis of the Seas and the Allure of the Seas are there, which are the biggest cruise ships in the world. These floating cities are extraordinary, everything needed to survive is on there and it functions just like any other city. They can even carry thousands of people at a time. I’ve been on cruise ships before and it feels like magic; everything is taken care off and at times it doesn’t feel like you’re out at sea. Cruise ships provide an important source of income through tourism not only to those working on the ships but to the ports of call that are visited (Cohen 2002); however, something we don’t think about the damage that cruise ships can cause. These ships can be a major source of waste and many times different cruise lines have been found guilty of illegally disposing of their waste. In fact some cruise lines like Regency Cruises, Celebrity Cruises, Princess Cruises, the Holland America line, and Royal Caribbean, among others, have been convicted in the past of illegally dumping oil, garbage, paint, plastic, ballast water and food waste into the waters of Alaska and the Caribbean (Cohen 2002). These acts have either been due to negligence, by accident or have been willful acts (Cohen 2002).

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Porpoises in Peril: Assessing Conservation Efforts for the Yangtze Finless Porpoise

by Zackery Good, RJD Intern

Imagine you are a Yangtze finless porpoise, swimming through the Yangtze River in China (Figure 1).  As you go about your daily business of finding food, you must navigate your way through heavy boat traffic, fishing gear, and water construction projects. The water you swim in is likely polluted and filled with debris.  However, there are some relatively safe areas in which you can seek refuge from these dangers.  The usefulness of these safe areas is evaluated in Zhao et al.’s 2013 publication Distribution patterns of Yangtze finless porpoises in the Yangtze River: implications for reserve management.

Figure 1, a Yangtze finless porpoise. Image via WikiMedia comons

Figure 1, a Yangtze finless porpoise. Image via WikiMedia comons

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Whale Funeral: Underwater Decomposition of Large Carcasses

by Emily Rose Nelson,
RJD Intern

Like any living thing, the lives of whales must come to an end at some point. Upon the death of these massive creatures some may strand and end up on shore, others may float and quickly be removed by other animals, and at least 50 percent will sink to the bottom of the seafloor. Whale carcasses reaching the depths of the ocean support high diversity by providing immense quantities of organic matter, a phenomenon known as a whale fall. The cold deep water acts as a refrigerator and slows decomposition significantly. Under these circumstances whales have the ability to live on after their death for over 50 years supporting entire communities in the deep sea.

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Who’s your daddy? A scientific perspective into the evolution of great white sharks

by Becca Shelton, RJD Intern

There are few things I love more than sharks and a good debate. The white shark, or great white, (Carcharodon carcharias) is my favorite species of extant sharks and the megalodon shark (Carcharodon megalodon) is my favorite extinct species. It just so happens that both species are in the center of an interesting dispute. Who is the ancestor to the white shark? For a long time, I personally had no doubt it was the megalodon shark because of similar looking teeth and jaws. In reality, this is not an easy question to answer. One of the reasons is that the species of sharks that are theorized to be the “closest” ancestor are extinct. Since sharks possess a cartilaginous skeleton, there is almost never a fully preserved skeleton since cartilage does not preserve well, unlike animals with boney skeletons. However, shark teeth are covered in enamel which helps in preservation and fossilized shark teeth can be found all over the world. Most of the debates surrounding this white shark ancestry involve teeth, especially morphology and serration. The two major theories I will be discussing are the megalodon hypothesis (Carcharodon megalodon) and the hastalis hypothesis (Isurus hastalis).

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Can fish feel pain?

By Fiona Graham, RJD Intern

Pain and suffering in fishes has been a hotly debated topic throughout the past, especially in the context of angling. While previous research has stated that fish might indeed feel pain, the authors of this paper decisively contradict these studies. This paper by Rose and colleagues details a comprehensive literature review and analysis of past studies claiming that fish feel pain. Specifically, they focus on deficiencies in the methods used for pain identification, and invalidating claims for consciousness in fishes.

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Open Ocean Migrations and Their Implications for Conservation

By Dani Escontrela, RJD Intern

Over time our understanding of animal migrations and habitats has greatly increased due to advances in tracking technology. Whereas before tags only told us when animals arrived and left certain places, tracks now are able to tell us about the migratory paths they follow. In addition other methods such as ship and plane surveys where limited to where we looked, however with tagged animals we can look were we hadn’t before. Marine animals have developed the ability to move across large ocean expanses, this is due to the fact that many times food resources and breeding sites may be separated by hundreds of kilometers. By understanding what drives these migrations, their seasonality and the paths they take we can help in the conservation and management of many species.

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Climate change influences sea turtle nesting

by Becca Shelton, RJD Intern

In David A Pike’s scientific paper Climate influences the global distribution of sea turtle nesting, Pike takes an in-depth look at which factors contribute to sea turtle nesting sites. There are 7 extant species of marine turtles that inhabit mainly tropical and subtropical waters and globally, are all considered to be endangered or threatened. Nesting site issues, whether they are abiotic or anthropogenic, appear to be a large contributor to sea turtle population decline. While there have been many studies on sea turtle nesting sites and conservation efforts to protect these areas, Pike’s study focuses more on the variables that attribute to the distribution of the ideal beaches for nesting and how future climate changes may affect them.

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