“How old are you?” is not a straightforward question for sharks

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When we are asked the question “How old are you?” we can usually answer with a degree of accuracy. Things are somewhat more complicated for fish and very much more for sharks – and not just because they can’t literally tell us how old they are.

The ageing of fish is believed to originate from speculations made by the scientist Aristotle in 340 B.C. He noted, in the Historica Animalium, that fish age may be determined by examination of the size and hardness of fish scales. However, it was not until the invention of the lenses and the microscope in 1650s, that scientists were able to identify growths rings in the scales that were similar to those found in trees. By 1924, these rings, known as annuli, were found in otoliths (ear bones), vertebrae, fin rays, and other hard structures. It was also noted that there were variations in the amount of growth over the year with the majority of growth occurring during the summer months.

Sharks and their relatives, rays and chimeras, do not have a bony skeleton. Their skeleton is made of cartilage which is lighter and more flexible. Their otoliths, or staticonia, are similar in size to sand grains and their scales (known as dermal denticles) do not grow continuously. Some species have hard spines that contain rings suitable for ageing, but this is not the case for many elasmobranchs. Vertebrae are used to age the species without spines and this is only possible after the animal is dead.

A thin section of shark vertebrae under the microscope showing the banding pattern (NOAA Fisheries)

Today ageing fish and shark species is a vital part of fisheries management. Ages are important data that are used for assessing the health of a population of a species (also known as a stock). The age of maturity and growth rates may tell us how vulnerable a species is to being over harvested.

Before we can confidently use age estimates for a species, the rate of growth ring deposition must be validated. This is frequently achieved by injection of fluorescent dyes (e.g. oxytetracycline, calcein) into a tagged animal prior to release. The dye incorporates into the age structures so that when the animal is recaptured, the point in time when the animal was tagged will be visible. Thus the amount of growth deposited since the tagging event can be confirmed.

Another method of age validation uses the levels of the radio-isotope of carbon known as  C14 in the growth zones of the vertebrae to match it against references with known timelines such as  coral reef cores. This isotope is a direct result of nuclear testing during the 1950s and has hence earned the title “bomb carbon dating”. However, a recent review of both these methods has suggested that the underestimation of shark ages may be more widespread than previously thought. Growth bands on aged structures may actually only be reliable during the early years of life. This new evidence will be important to future ageing studies and the resultant impact to the life history and conservation status of sharks and rays.

Rock saw used to section otoliths and vertebrae

Thanks to the ongoing collaboration with Sea Leucas, a small start-up in the field of fish ageing, MarAlliance now has ready access to two age/production saws for taking sections of shark vertebrae and fish spines and otoliths. We have begun to process our collections and look forward to working with other researchers along the MesoAmerican Reef to age their animals.

 

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Asistente de comunicación (Internship)

MarAlliance es una organización internacional sin ánimo de lucro registrada en EE.UU., Belice, Panamá y Cabo Verde, cuyo objetivo es explorar, facilitar e inspirar cambios positivos para la fauna marina amenazada, especialmente tiburones y rayas, sus hábitats críticos y las comunidades humanas dependientes. Nuestra misión es amplia y ambiciosa, y trabajamos en tres idiomas y en siete países de tres regiones. Ante el declive de muchas poblaciones de megafauna marina, estas especies necesitan una voz fuerte, eficaz y con base científica que las represente para ayudar a los socios dependientes a dar forma a las estrategias y acciones de gestión y conservación para invertir el declive.

Resumen del puesto:

Buscamos a un becario (6 meses) proactivo, con conocimientos digitales y excelente capacidad de redacción y edición de textos, que apoye la creación de contenidos escritos de alta calidad y recursos multicanal para difundir el trabajo que MarAlliance realiza a través de sus plataformas en línea (sitio web, redes sociales, boletín, entre otras) y fuera de línea, y que interactúe con nuestro público externo para contribuir a nuestros objetivos generales de comunicación y marketing. El Asistente de Comunicación dependerá directamente del Coordinador de Comunicación y Marketing, y trabajará en estrecha colaboración con el resto del equipo para apoyarles en los elementos de comunicación de su trabajo.

Las funciones y responsabilidades incluirán, entre otras, las siguientes:

  1. Proporcionar apoyo creativo, editorial y operativo a los proyectos. 
  2. Apoyo en la organización, etiquetado y etiquetado del archivo fotográfico y gestión del archivo de vídeo.
  3. Gestión de la comunidad: Gestionar activamente los canales de medios sociales, así como identificar nuevas tendencias y oportunidades de colaboración. Generar reels y visuales.
  4. Apoyo en la redacción de artículos de blog (SEO) y contenido de boletines. 
  5. Ayudar a construir y desarrollar materiales, herramientas y acciones para campañas (online y offline).
  6. Ayudar en diferentes tareas relacionadas con la comunicación trabajando mano a mano con contratistas externos (desarrollador web, diseñador gráfico…) para mejorar el compromiso de las audiencias externas.
  7. Apoyo en la elaboración de informes de campañas y comunicaciones (Google Analytics, métricas de redes sociales, informes de marketing por correo electrónico).
  8. Como parte del Equipo de Comunicación de MarAlliance, apoyar al Coordinador de Comunicación y Marketing en cualquier otro proyecto de comunicación, coherente con las habilidades y experiencia del titular del puesto, en circunstancias no rutinarias.

Experiencia, conocimientos y aptitudes requeridos:

  1. Licenciatura en comunicación, periodismo, marketing o cualquier disciplina relacionada.
  2. Experiencia en comunicación digital o marketing.
  3. Pasión e interés por la naturaleza, la vida marina y la conservación.
  4. Capacidad demostrada para redactar y presentar comunicaciones creativas.
  5. Presencia y conocimientos de medios sociales y digitales.
  6. Capacidad para realizar múltiples tareas y detectar buenas historias.
  7. Capacidad para trabajar a distancia y cumplir los plazos establecidos.
  8. Conocimientos de diseño gráfico deseables, pero no necesarios.
  9. Conocimientos de edición de vídeo deseables pero no necesarios. 

Salario y prestaciones:

Estipendio durante 6 meses.

Idiomas:

Español, con fluidez en inglés

Localización:

Nacionales o residentes de Panamá, Belice, México, Honduras, Guatemala.

Este contrato será a distancia dentro de las zonas horarias de América, flexible, a tiempo completo y desde casa con hasta un 10% de viajes ocasionales locales e internacionales.

Cómo presentar la candidatura:

Por favor, envíe su currículum, portfolio si lo tiene, y carta de presentación a info@maralliance.org con “MAR-CA_Apellido” en el asunto antes del 21 de marzo, 2024. No se admiten llamadas.

Communications Assistant (Internship)

MarAlliance is an international non-profit registered in the US, Belize, Panama and Cabo Verde that aims to explore, enable and inspire positive changes for threatened marine wildlife – notably sharks and rays – their critical habitats and dependent human communities. Our remit is broad and ambitious, and we work in three languages and across seven countries encompassed by three regions. In the face of declines in many populations of marine megafauna, these species need a strong, effective, and science-based voice to represent them to help dependent partners shape management and conservation strategies and action to reverse declines.

Position summary:

We are seeking for a proactive, digitally savvy Paid Intern (6 month) Communications Assistant with excellent writing and copy editing skills, who will support the creation of high-quality written content and multichannel assets to broadcast the work MarAlliance does through its online (website, social media, newsletter, among others) and offline platforms, and engage with our external audiences to contribute to our overall communications and marketing goals. The Communications Assistant will directly report consistently to the Communications and Marketing Coordinator, and work closely with the rest of the team to support them on the communications elements of their work.

Duties and responsibilities will include but are not limited to:

  1. Provide creative, editorial, and operational project support. 
  2. Support organizing, labeling and tagging the photo archive and video archive management.
  3. Community Management: Actively manage social media channels, as well as identify new trends and collaboration opportunities. Generate reels and visuals.
  4. Support with writing blog articles (SEO) and newsletter content. 
  5. Help build and develop materials, toolkits, and actions for (online and offline) campaigns.
  6. Assist in different communications-related tasks working hand in hand with external contractors (web developer, graphic designer…) to improve the engagement of external audiences.
  7. Support in campaign and communications reporting (Google Analytics, social media metrics, email marketing reports)
  8. As part of the MarAlliance Communications Team, support the Communications and Marketing Coordinator with any other communications projects, consistent with the skills and expertise of the post holder, in non-routine circumstances.

Experience, Knowledge, and Skills Required:

  1. Bachelor’s degree in communications, journalism, marketing or any related discipline.
  2. Experience working in digital communications and or marketing.
  3. Passion and interest for nature, marine life and conservation.
  4. Proven ability to write and deliver creative communications.
  5. Social Media and digital presence and knowledge.
  6. Ability to multitask and spot good stories.
  7. Capable of working remotely and meeting established deadlines.
  8. Graphic design skills are desirable but not required.
  9. Video editing skills are desirable but not required.

Salary and benefits:

Stipend for 6 month.

Language:

English, Spanish are mandatory.

Location:

Panama, Belize, Mexico, Honduras, Guatemala nationals or residents. 

This contract will be remote within the Americas time zones, flexible, full-time and home-based with up to 10% occasional local and international travel.

How to apply:

Please send your resume, portfolio if you have one, and cover letter to info@maralliance.org with “MAR-CA_Last name” in the subject line by 21st of March, 2024. No calls please.