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Issue 92 - January 2023

Fish Larvae Find Their Way Using External Cues, New Study Finds

By The University of Miami

Rosenstiel School-led study offers new insights into the early-life stage of marine fish

Miami, FL —The first global analysis of larval orientation studies found that millimeter-sized fish babies consistently use external cues to find their way in the open ocean.  There are many external cues available to marine fish including the Sun, Earth’s magnetic field, and sounds. The new study, led by scientists at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science offers important insight into understanding this perilous phase of marine fish.

Understanding the mechanisms that fish larvae use during their pelagic journey is critical for scientists to better predict their dispersal, the connectivity of marine protected areas, and the structure of marine fish populations.

“This study highlights the importance of a deeper understanding of larval orientation mechanisms and suggests the concept of vector navigation in the early life history of fish,” said the study’s senior author Claire Paris, a professor of ocean sciences at the Rosenstiel School.

Once considered passive drifters relying on ocean currents to get them to their nursery grounds, the Rosenstiel School researchers, together with multiple collaborators, showed that for many species around the world from tropical to temperate regions, fish larvae are able to control their destination and migrate by keeping a bearing.

The researchers analyzed nearly two decades of studies using two methods to collect data on an unprecedented number of larvae of multiple species and locations. One method used is a Drifting In Situ Chamber instrument invented by Paris that consists of an underwater chamber with an imaging system to record larval fish swimming behavior in their natural settings. The second method used is the Following method developed by Jeff Leis, an ichthyologist at the University of Tasmania, in which two scuba divers follow late-stage larvae while recording the bearing and swimming speed. Movement patterns obtained by these two experimental methods were compared to theoretical movement patterns expected under the strict use of internal cues. The results from this combined approach strongly supported the oriented movement by fish larvae.

“Our study is the first to show that this is achieved using external directional cues, providing a systematic and global indication for the robust use of external cues by fish larvae for orientation. This is important since a better understanding of the larval stages can facilitate the management and conservation of marine populations” said the study’s lead author Igal Berenshtein, a postdoctoral researcher in the Department of Ocean Sciences at the Rosenstiel School.

“It’s extraordinary that these tiny fish larvae find their way in a vast ocean,” said Paris. “We can learn from them to fundamentally advance fisheries models and the science of underwater navigation.”

The study, titled “Evidence for a consistent use of external cues by marine fish larvae for orientation,” was published on December 2, 2022, in the journal Communications Biology. The study’s authors include Claire Paris, Igal Berenshtein, Robin Faillettaz from the University of Miami Rosenstiel School, Jean-Oliver Irisson from the Laboratory of Oceanology of Villefranche-sur-Mer and the CNRS; Moshe Kiflawi from the Ben-Gurion University of the Negev; Ulrike Siebeck from the University of Queensland; and Jeffery Leis from the University of Tasmania.

The study was supported by a National Science Foundation grant (NSF-OCE 1459156).

Attached image caption: Claire Paris, professor of ocean sciences (center left), and co-author Jean-Olivier Irisson (center right) deploy the Drifting In Situ Chamber (DISC), equipped with an imaging system designed to record larval fish swimming behavior in their natural settings during an expedition at the Australian Museum Lizard Island Research Station. Photo: Lyle Vail


About the University of Miami

The University of Miami is a private research university and academic health system with a distinct geographic capacity to connect institutions, individuals, and ideas across the hemisphere and around the world. The University’s vibrant and diverse academic community comprises 12 schools and colleges serving more than 17,000 undergraduate and graduate students in more than 180 majors and programs. Located within one of the most dynamic and multicultural cities in the world, the University is building new bridges across geographic, cultural, and intellectual borders, bringing a passion for scholarly excellence, a spirit of innovation, a respect for including and elevating diverse voices, and a commitment to tackling the challenges facing our world. Founded in the 1940’s, the Rosenstiel School of Marine, Atmospheric, and Earth Science is one of the world’s premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. www.earth.miami.edu.


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Issue 92 - January 2023

SEVENSEAS Travel Magazine – January 2023 – Issue 92

Cover Issue 92 January 2023

Feature Destination

Pavones, Costa Rica, a Surfer’s Paradise

Waves for surfing in Costa Rica

This incredible beach is located in the canton of Golfito in Puntarenas, in the south of the country. In addition to its abundant plant growth, it is known for another special reason, a meeting place for those who love surfing and are passionate about great waves. The waves of Pavones are second only to those of Chicama, Peru. Read more…

Costa Rica Receives First Emission Reductions Payment from Forest Carbon Partnership Facility

Costa Rica climate action

Costa Rica has become the first country in Latin America and the Caribbean to receive payments from a World Bank trust fund for reducing carbon emissions from deforestation and forest degradation—commonly known as REDD+. Read more…

Feature Destination: Visit Costa Rica

humming bird at a flower in Costa Rica

With a goal to be the first carbon-neutral country in the world by 2021, sustainable practices are observed in every region of the country, across all industries, adopted by all citizens and embraced by visitors. From local Costa Rican cuisine to artisan crafts to traditional customs and celebrations, sustainability is embedded deeply in the culture and traditions of Costa Rica. Read more…


NEWSROOM

11th Hour Racing Awards New Grants to Nonprofit Organizations to Restore Marine Ecosystems and Ocean Health

Connecticut College professor Dr. Maria Rosa and students are deploying 80 Reef Balls to help restore tidal marshes in Connecticut.

11th Hour Racing announced today eight new grants, funded by The Schmidt Family Foundation, to nonprofit organizations in the U.S. and Puerto Rico. Read more…

Scientists Announce New Names of 20 Critically Endangered North Atlantic Right Whales

Scientists have unveiled the news names of 20 cataloged North Atlantic right whales, an annual tradition that helps researchers in the field more easily identify individual whales with recognizable features. Read more…

A DIVER’S GUIDE TO THE WORLD: Remarkable Dive Travel Destinations Above & Beneath the Surface by Carrie Miller & Chris Taylor

Over the course of 14 months, National Geographic travel expert Carrie Miller and dive master Chris Taylor traveled to 50 inspirational locations around the world. Read more…

Fish Larvae Find Their Way Using External Cues, New Study Finds

The first global analysis of larval orientation studies found that millimeter-sized fish babies consistently use external cues to find their way in the open ocean.  There are many external cues available to marine fish including the Sun, Earth’s magnetic field, and sounds. Read more…

Invasive Black Carp Established in Parts of The Mississippi River Basin

Black carp, which are an invasive fish species in North America, is now known to be established in the wild in parts of the Mississippi River basin. A new study co-authored by the U.S. Geological Survey is the first to identify an established population. Read more…

Massive “Marimo” Algae Balls at Risk from Deadly Winter Sunburn

Climate change could overexpose rare underwater “marimo” algae balls to sunlight, killing them off according to a new study at the University of Tokyo. Marimo are living fluffy balls of green algae. Read more…

New Research: As “Connector Species,” Birds Are Essential to the Health of Both Islands and Oceans

Islands around the world have been decimated by introduced invasive species, but restoring islands — with a special focus on saving seabirds — provides benefits across land and sea.  Read more…

SAWFISH NEWS: What Does Recovery Mean for Endangered Smalltooth Sawfish?

Following the population decline of smalltooth sawfish in the United States and the 2003 listing under the Endangered Species Act (ESA), a team was assembled to recover the population of this endangered species. Read more…

The 2022 Report Card on the Health of the Mesoamerican Reef Released

Less than ten percent of the Mesoamerican Reef coral reef area is fully protected from fishing, with three out of four countries now having critically low grouper and snapper biomass. Reefs like Cozumel, Mexico. Read more…

Guy Harvey Academy of Arts & Science Opens at Anna Maria Elementary in Bradenton, Florida

Dr. Guy Harvey tours Anna Maria Elementary and meets students along the way. Banner

The Guy Harvey Foundation has been working closely with the School District of Manatee County to develop an art, math, and science-based curriculum to educate and engage young students on the importance of preserving our oceans and marine life while learning about the world’s environment. Read more…

Court Recommends Halting Alaska’s Unsustainable Harvest to Protect Wild Chinook & Southern Resident Killer Whales

In a massive international and coast-wide decision for wild Chinook and Southern Resident killer whale recovery, Seattle’s federal Court issued a landmark opinion on Tuesday that recommends terminating unsustainable commercial salmon harvest that has persisted for decades until new environmental reviews of those fisheries occur. Read more…

Scientists Call for Urgent Conservation of Deep Reefs, One of The Planet’s Largest & Least Protected Ecosystems

As world leaders, government negotiators, scientists, and conservationists gather ahead of the UN Biodiversity Conference, COP15, to agree to halt and reverse nature loss, an international team of marine scientists and conservationists have made an impassioned plea. Read more…

Slowing Water for Greener Neighborhoods By Dr. Rob Moir

Climate Change has brought fiercer storms with devastating floods and long-lasting droughts that stressed and killed plants and animals. Once we controlled water. These days, water is in control and is harming us. Read more…


SEVENSEAS Beach Cleanups

In August 2022 CleanUp, we picked up over 80 kilogram of plastic, pieces of glasses, tractor tyre, and fishing nets from the beach in Krabi, Long Beach or Pan Beach. Of course, we would not be able to do it without your support. You can make a tax-deductible donation here to keep our publications and Thailand Cleanup Project afloat.

You can either make a direct financial contribution to SEVENSEAS Media through The Ocean Foundation website or connect us with potential donors by sending an email to  Giacomo Abrusci, our Editor-in-Chief.


The FREE Weekly Conservation Post and Jobs List

Signing up for the free Weekly Newsletter & Jobs List will get you a round-up of upcoming events, webinars, meetings, reports, funding opportunities, photos of the week, and recent postings to the jobs list.

To sign up for our free subscription, please Click Here or email us Here

Since 2004, SEVENSEAS Media has fostered an informal and non-partisan platform to promote understanding of key issues and challenges while building partnerships across an increasingly diverse group of marine conservation professionals and students.

Our mission is to promote communication and build partnerships across the global marine community and to identify and address gaps in the community’s work. SEVENSEAS Media achieves this through multimedia promotion and partnerships. The community consists of a diverse and growing group of participants, including non-governmental organizations, government agencies, foundations, bilateral and multilateral agencies, fellowship programs, independent consultants, and academia/students.

If you are interested in contributing or getting involved, email us Here


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Issue 92 - January 2023

The 2022 Report Card on the Health of the Mesoamerican Reef Released

Contributed By Healthy Reefs for Healthy People

Less than ten percent of the Mesoamerican Reef coral reef area is fully protected from fishing, with three out of four countries now having critically low grouper and snapper biomass. Reefs like Cozumel, Mexico – that are fully protected and enforced – demonstrate their capacity for sustainable use and resiliency.

Bacalar Chico, Doctorfish and Parrotfish, by Henry Brown

MESOAMERICAN REEF — The 2022 Report Card on the Health of the Mesoamerican Reef was released today by the Healthy Reefs Initiative (HRI), a collaboration of over 70 organizations dedicated to the conservation of the Mesoamerican Reef (MAR) in Mexico, Belize, Guatemala, and Honduras. It reveals that reef health has dropped for the second time  – reaching the same “Poor” rating (2.3 out of 5) that was first measured in 2006 and down from the “fair” rating (2.8) attained five years ago. These data come from 234 reef sites assessed with a standard methodology by 77 surveyors from 36 different organizations from June to December 2021.

The Mesoamerican Reef system includes four off-shore atolls, barrier, fringing, and patch reefs encompassed within 1324 km2 of coral reef habitat distributed among 17 subregions, eight of which are now in critical condition for commercial fish biomass. Belize experienced the greatest decline in reef health caused primarily by the over 50% reduction in both commercial and herbivorous fish biomass, likely due to reduced enforcement and sustained fishing during COVID restrictions.

The Reef Health Report Card tracks four indicators to understand changes in reef health over time: live coral cover,  fleshy macroalgae cover, the biomass of key herbivorous and commercial fish species. Reef Health can be assessed for each indicator or for the integrated Reef Health Index, which equally considers all four indicators. Evaluations can be considered at the site, subregion, country, or full Mesoamerican Reef scale. In all these cases the message is clear – we urgently need to increase reef protection. Fish populations are now critically low in every country, except Mexico. Most of the 17 subregions are in “poor condition”, with Cozumel, Mexico as the only subregion in ‘good’ condition for overall reef health. Interestingly, Cozumel also has the highest percent of its coral reef area within full protection from all fishing  (35%) and is the only subregion with ‘very good’ conditions for commercial and herbivorous fish. These data demonstrate the value of full protection, particularly when local communities are involved in the management and are benefiting economically. 

Maria José González, Executive Director of the Mesoamerican Reef Fund said, “This 2022 Report Card is sobering and an immediate call to action. The International Development Bank’s 2021 economic valuation of the Mesoamerican Reef found it provides goods and services valued at about US$4.5 billion per year, which we stand to lose if we allow the reef to further decline. We need to turn this threat into an opportunity to engage the private sector and innovate more market-based initiatives that will reduce the threats to the reef and generate income for local communities. Inaction is not an option.”

The four MAR countries have designated over 50 MPAs that cover 56% of the territorial waters in the MAR. Most are actively managed. But most of the MPAs still allow fishing – only 2.4% of the territorial waters are in full protection – ranging from 1.8% in Belize to 12% in Guatemala. “We are eager to study the ecological response and potential recovery of fish populations in Guatemala, after declaring our first fully protected reef area in the amazing Cayman Crown reef in 2020,” said Ana Giró, HRI’s Coordinator for Guatemala.

This is the seventh HRI Report Card issued since 2008, with all of them including the recommendation to put 20% of the sea under full protection from all fishing, in order to replenish heavily exploited populations and restore the reef’s complex ecological functioning. “We talk a lot about Marine Protected Areas (MPAs), and allocate considerable financial resources for their management,” said Dr. Melanie McField, Director of HRI and a Smithsonian coral reef scientist with over 30 years of experience working in the region. “ We now need this protection to become absolute, along with our resolve to enforce it.” 

The percent of the coral reef habitat under full protection is somewhat better, with 9% region-wide,   ranging from 7% in Belize to 15% in Mexico. Notable is that Mexico is also the only country whose commercial fish biomass is not in critical condition. Full protection will help sustain the fisheries and reef health.  Increasing this to 20% could further enhance and support the fisheries outside the fully protected zones due to the exponential increase in offspring produced by “big mamma” fish within the fully protected zones. “If we had actually placed 20% of the MAR under full protection 15 years ago when we first recommended it, the region would now be reaping the benefits of more productive fisheries, improved reef health, and increased tourism value in the fully protected zones,” McField said.

While fish decline is the main issue highlighted in this report, we continue to deal with high levels of fleshy macroalgae that can impede coral growth and reproduction. Additionally, while coral cover has remained relatively stable, threats such as stony coral tissue loss disease and climate change have impacted coral communities and reduced their diversity. We have lost 44% of our reef-building boulder corals, leaving space for more opportunistic, non-framework-building species and macroalgae. This change in species composition translates to reduced growth and lower calcium carbonate accretion (our coral’s building blocks) making our reefs highly susceptible to erosion and other impacts, reducing their services such as coastal protection and resiliency.

This precarious balance for the coral community is particularly evident in Mexico and Honduras, where even total live cover has declined since our last assessment.  “Our state continues to face the challenges of balancing economic development with the integrity of our most fragile ecosystems such as coral reefs, however, one cannot exist without the other. The goal of our government is to consolidate sustainable growth that conserves and restores our ecosystems with a social commitment to our communities so that no one is left behind. We congratulate and join the great work carried out by HRI for our reefs,” said Huguette Hernández, Secretary of Ecology and Environment of the Government of the State of Quintana Roo (SEMA).

We know that escalating stress from global climate change and disease outbreaks are now impacting our reef, while the decades-old problems of sewage and agricultural nutrient pollution continue to fuel macroalgal proliferation and pathogens. Thus, our reef is being assaulted on many fronts and our meager defensive tactics are languishing. We need bold offensive strategies to propel reefs into a better ecological condition – by actually managing our wastewater and agricultural runoff, controlling coastal development, increasing reef herbivory, and restoring commercial fish by implementing fully protected zones to replenish critically depleted populations.

“With the increasing threats confronting the MAR, this Report Card provides an urgent call to action and a persistent reminder that these ecosystems need more protection. It also provides the baseline from which we can assess the impact of our conservation and management efforts,” said Dr. Jake Snaddon, Director of the University of Belize Environmental Research Institute. 
Governments need to commit to fully protect at least 20% of the sea, as the core of the 30% highly protected that is part of the 30X30 commitments; municipalities and businesses need to invest in adequate sewage treatment, while governments and communities need to collaborate to prevent massive coastal developments with irreparable ecological and social damages. Finally, we all need to become more politically engaged in these decisions and reduce our individual carbon footprints by adopting more sustainable lifestyles, particularly our food/protein choices.

For more information, please visit https://www.healthyreefs.org/cms/

Banco Chinchorro by Lorenzo Álvarez Filip

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Issue 92 - January 2023

SAWFISH NEWS: What Does Recovery Mean for Endangered Smalltooth Sawfish?

Contributed by Tonya Willy, Havenworth Coastal Conservation
© Beau Yeiser

Following the population decline of smalltooth sawfish in the United States and the 2003 listing under the Endangered Species Act (ESA), a team was assembled to recover the population of this endangered species.  But what is recovery and how do we achieve it for smalltooth sawfish?  

Under the ESA, recovery is defined as the process of restoring endangered and threatened species to the point where they no longer require the safeguards of the Act.  To guide managers and researchers in that recovery process, the ESA directs NOAA Fisheries (or U.S. Fish and Wildlife Service in the case of terrestrial animals) to develop recovery plans.  Recovery plans outline the paths and tasks required to restore and secure self-sustaining wild populations. They are guidance documents that describe, justify, and schedule the research and management actions necessary to support recovery of a species.      

A recovery plan for smalltooth sawfish in the U.S. was published in 2009 and outlines specific criteria for downlisting (a reclassification from endangered to threatened) and delisting (a reclassification from threatened to recovered).  Sawfish may be delisted on the basis of recovery only if the best available scientific and commercial data indicate an improvement in the status of the species to the point where it is no longer appropriate to be considered endangered.  For smalltooth sawfish that means ensuring the long-term viability of the species through substantial increases in both abundance and range.         

Smalltooth sawfish in the U.S. are considered to be, and managed as, one single population.  This means that under ESA regulations, all sawfish receive equal and consistent protections regardless of where they are geographically.  Sawfish in Everglades National Park are just as protected and equally important to the population as those in Tampa Bay, Indian River Lagoon, Texas, or Georgia.  Since the species is managed as a single population, not individual geographic populations, only the species as a whole can be considered recovered.  In other words, smalltooth sawfish cannot be locally or regionally recovered such as in one particular bay system. 

While we are starting to see some encouraging signs in the population, we are certainly a long way from recovery.  Modest increases in sawfish numbers are likely the result of the 1992 protection from harvest in Florida waters, the 1995 Florida gillnet ban, and the 2003 ESA listing which have all aided in reducing mortality, and a substantial increase in important outreach and education efforts over the last two decades.  However, until recovery is truly documented, it is critical that local, state, and federal regulations and protections remain in place in all areas of the U.S. to ensure the continued improvement in the smalltooth sawfish population.

You can also help scientists track recovery of the population and steer research efforts by sharing information about your sawfish catches and sightings by visiting www.SawfishRecovery.org, calling 1-844-4SAWFISH, emailing sawfish@myfwc.com, or entering the details in the FWC Reporter App.  For more information on protected species recovery visit https://www.fisheries.noaa.gov/insight/recovery-endangered-and-threatened-species



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