Viviendo a Pesar de la Crisis: Buceo con Tiburones

Muy buenas,

Este puente de Diciembre volvemos por segunda vez a las rutas Centro y Sur del Mar Rojo:

http://viviendoapesardelacrisis.blogspot.com/2014/06/buceo-en-el-mar-rojo-egipto.html

Las inmersiones son en pináculos en alta mar, con muchas corrientes y tiburones:

Daedalus, Sataya, Fury Shoal, Zabargad, Rocky, St Johns, Islas Brothers, Elfinstone,...

https://en.wikipedia.org/wiki/Daedalus_Reef

https://en.wikipedia.org/wiki/Elphinstone_Reef

https://en.wikipedia.org/wiki/El_Ikhwa_Islands

Nota: A mi hermano le encanta pero a mi me aburre un poco ya que todas las inmersiones son en el mismo plan: Coger profundidad, buscar en el azul desde la pared o plateau, ir perdiendo profundidad y acabar a poca profundidad en la pared.

Aprovecho para hacer una recopilación:

Nota: Nuestros divelogs:

https://viviendoapesardelacrisis.blogspot.com/2014/08/logbook-o-divelog-diario-de-buceo.html

https://viviendoapesardelacrisis.blogspot.com/2016/05/logbook-o-divelog-diario-de-buceo-de-mi.html

-El primero? Recuerdo estar cerrando grupo durante un salto por el azul entre Shark y Yolanda Reef cuando miré hacia abajo y, distraidamente, me pareció ver una sombra. Para cuando me di cuenta y volví a mirar, ya no pude volver a ver nada. Siempre me ha quedado la duda de si fué o no. :P

http://de.wikivoyage.org/wiki/Anemone_City,_Shark-Riff_und_Jolanda-Riff

-Tiburones Toro (https://en.wikipedia.org/wiki/Bull_shark) en Méjico:

Carcharhinus leucas:

https://viviendoapesardelacrisis.blogspot.com/2015/07/buceo-en-el-riviera-maya-mejico.html

Por ahí andamios!

Nota: La inmersión se hace desde la playa y nos colocamos de rodillas sobre el fondo a lo largo de una línea mientras se da de comer a los tiburones en frente nuestro y otros buzos vigilan nuestras espaldas.

Y, antes de que se me olvide:
http://www.savingoursharks.org/

-Tiburones Puntas Blancas (https://en.wikipedia.org/wiki/Whitetip_reef_shark) y Puntas Negras (https://en.wikipedia.org/wiki/Blacktip_reef_shark y https://en.wikipedia.org/wiki/Blacktip_shark) en Egipto y Maldivas:

Triaenodon obesus:

Carcharhinus melanopterus:

Carcharhinus limbatus:

https://viviendoapesardelacrisis.blogspot.com/2018/03/buceo-en-maldivas.html

-Tiburón Martillo (https://en.wikipedia.org/wiki/Hammerhead_shark) en Egipto: Bancos precedidos por un explorador.

Familia Sphyrnidae:

P.D: A 47 metros:

https://viviendoapesardelacrisis.blogspot.com/2017/07/a-47-metros.html

-Tiburón (Puntas Blancas) Oceánico (Longimanus) (https://en.wikipedia.org/wiki/Oceanic_whitetip_shark) en Egipto:

Carcharhinus longimanus:

Nota: En la primera foto estoy colgado del cabo de la popa del barco haciendo la parada mientras nos ronda un longimanus. Nos pega una pasada y desaparece para volver a ver que se acerca bajo la sombra del barco y aviso al grupo para volver a estar un rato con él (varias pasadas más en las que casi se lleva por delante a uno de los fotógrafos).

P.D: Mi pelo, Dioz!

https://viviendoapesardelacrisis.blogspot.com/2019/04/tximas-grenas-pelo.html

-Tiburones Nodriza (https://en.wikipedia.org/wiki/Nurse_shark) en Maldivas y Méjico (Cozumel):

Ginglymostoma cirratum:

...

-Tiburón Ballena (https://en.wikipedia.org/wiki/Whale_shark) en Maldivas y Méjico: Nos pasó uno por encima del arrecife en Maldivas e hicimos snorkel con otros en Méjico.

Rhincodon typus:

-Tiburón Azul (Tintorera) (https://en.wikipedia.org/wiki/Blue_shark) en el Cantábrico (desde Bermeo): Snorkel en alta mar durante varias horas:

Prionace glauca:

https://viviendoapesardelacrisis.blogspot.com/2019/02/salir-alta-mar-con-cebo.html

...

A ver cómo nos va en dos semanas!

Actualización a 24/11/2022: Una semanita... Cierto, se me había olvidado. Ante la pregunta de si se pasa miedo o no:

-Definitvamente, NO. De hecho, siempre decimos que los bichos huyen de la gente o, como mínimo, mantienen una distancia.

-Lo que sí es verdad es que la distancia es relativa y se nos hace rara con ciertos bichos.

Recuerdo una vez cerrando grupo por una pared cuando pude ver perfectamente como un tiburón subia diagonalmente la pared hacia nuestra espalda, se giraba y nos seguía cada vez más cerca mientras lo miraba preguntándome por qué y para qué se acercaba tanto.

Y lo longimanus, que siempre digo que son como perros olisqueando todo en busca de comida. Se acerca, acerca y acerca hasta el punto de que nos ponemos nerviosos y, justo al final, pega un quiebro y se aleja.

Éso sí, los tiburones (no así como ciertas inmersiones donde se los trata como animales de circo) son HERMOSOS y es una PASADA ver cómo se mueven e interactuan con nosotros.

Actualización a 09/12/2022: Menudo chasco! Acabamos de volver de una semana bastante light y de mala mar en la Ruta Sur de Egipto. :(

Sólo hemos visto puntas blancas de arrecifes (unos 5):

Actualización a 12/12/2022: Resulta que hubo otro barco de Emperor por la zona y, además de que estaba lleno de españoles, empezaron la ruta por el Norte y fueron bajando. Justo lo contrario que hicimos nosotros y acertaron porque nosotros nos íbamos encontrando con peores condiciones según subíamos hacia arriba. Hasta el punto de que tratamos de ir a Elfinstone al final de la semana pero había olas de 2,5 ms.

Estuve hablando con los españoles cuando volvimos a Port Ghalib y vieron DE TODO! Un tiburón ballena en Daedalus, longimanus arriba y martillos abajo a la vez, tiburones sedosos,... Para colmo era gente jovén, estaban de farra y había bastantes tías. Dioz! :P

-Tiburón Sedoso (https://en.wikipedia.org/wiki/Silky_shark):

Carcharhinus falciformis:

Nada, hemos decidido no volver en Diciembre al Mar Rojo ya que hace viento desagradable y hay peligro de mala mar.

Actualización a 15/12/2022: Según veo, me dejé varios tipos de tiburones del anterior viaje del 2017:

-Tiburón Zorro (https://en.wikipedia.org/wiki/Common_thresher):

Alopias vulpinus:

-Tiburón Gris (https://es.wikipedia.org/wiki/Carcharhinus_amblyrhynchos):

Carcharhinus amblyrhynchos:

Actualización a 03/03/2023: Cruzando el Mar Rojo a nado:

https://www.weforum.org/agenda/2022/11/lewis-pugh-red-sea-swim-coral-reefs-ocean/

https://lewispughfoundation.org/red-sea-2022

https://lewispughfoundation.org/red-sea-swim

https://lewispugh.com/red-sea/

Y lidiando con los tiburones:

Actualización a 09/06/2023: Buff!

https://english.ahram.org.eg/NewsContent/1/1238/502655/Egypt/Tourism/Russian-national-killed-in-Red-Sea-Tiger-shark-att.aspx

https://twitter.com/AlanAbdo13/status/1666816998284865536

Actualización a 10/06/2023: Ya está...

https://twitter.com/RedaElsayed__/status/1666843432319328257

https://twitter.com/DramaAlert/status/1667280533787639810

https://twitter.com/uncensoredpromo/status/1667243724168896512

...solucionado. :(

Actualización a 27/07/2023: A ver...

Actualización a 31/07/2023: Más:

https://www.revistaaqua.com/curso-de-interaccion-extrema-con-tiburones/

Actualización a 27/09/2023: Más:

https://www.sharkmeasurements.com/

https://www.nature.com/articles/s41598-023-39560-1

Actualización a 27/10/2023: Vaya!

https://www.linkedin.com/posts/azti_gestiaejnpesquerasostenible-golfodebizkaia-activity-7123549185307533312-eTvo

https://www.azti.es/proyecto-estudiar-comportamiento-tiburones-y-proteger-ecosistema-marino-en-golfo-bizkaia/

Actualización a 09/11/2023: Jooder...

Actualización a 14/01/2024: A ver:

Actualización a 23/02/2024: Vaya!

https://www.nps.gov/maca/learn/news/two-new-species-of-ancient-sharks-identified-through-research-at-mammoth-cave-national-park.htm

Actualización a 01/03/2024: Hay ganas!

Actualización a 24/04/2024: Tiburón Ballena en Galápagos?

Actualización a 29/04/2024: Mar de Cortez:

Actualización a 18/05/2024: Wow!

Edit:

Actualización a 23/05/2024: La gente es IDIOTA:

https://www.doc.govt.nz/news/media-releases/2024-media-releases/orca-body-slam-shocks-doc-leads-to-infringement-fine/

Orca ‘body slam’ shocks DOC, leads to infringement fine

-A man who leapt from a boat into the water near two orca has been slapped with a $600 infringement in an incident DOC staff say displays a shocking and stupid attitude to protected marine mammals.

Actualización a 15/07/2024: Pobres bichos:

https://news.fiu.edu/2023/reef-sharks-are-at-much-higher-risk-of-extinction-than-previously-thought

Reef sharks are at much higher risk of extinction than previously thought
-Protected areas and fisheries management key to survival

Actualización a 02/09/2024: Más:

Actualización a 10/09/2024: Cojonudo:

https://www.lancaster.ac.uk/news/sharks-are-abandoning-stressed-coral-reefs-in-warming-oceans

Sharks are abandoning stressed coral reefs in warming oceans
9 September 2024 10:27

Grey reef sharks are having to abandon the coral reefs they call home in the face of warming oceans, new research finds.

Scientists, using a combination of satellite remote sensing and a network of acoustic receivers on the seabed, have discovered sharks are deserting coral reefs at times of environmental stress, such as high temperatures that can lead to coral bleaching events.

The effects on these sharks, normally strongly attached to particular areas of shallow reef habitats, include lower residency, more widespread and frequent movements to different areas and longer periods of absence entirely.

Worryingly, these effects persisted for extended periods of up to 16 months following extreme stress periods such as the 2015-2016 El Niño event, which caused substantial bleaching in the study region.

As climate change is predicted to cause bleaching events annually by 2043 this behavioural change is “concerning” say the scientists.

An international research team, led by marine scientists at Lancaster University and ZSL, and funded by the Bertarelli Foundation, attached acoustic trackers to more than 120 sharks and installed receivers around coral atolls to monitor shark movements at reefs in the Indian Ocean between 2013 to 2020.

They recorded more than 714,000 acoustic detections and, in collaboration with Earth Observation scientists at King’s College London, combined these with satellite data recording different metrics of reef environmental stress.

Scientists behind the study say this has important consequences for both the sharks and the reefs.

“These results provide some of the first evidence of how reef change in response to environmental stress, something that is becoming both more extreme and more frequent, is affecting the movement of sharks,” said Dr David Jacoby of Lancaster University and Principal investigator on the research project. “Grey reef sharks are a common, resident predator to the reefs of the Indo-Pacific, venturing away from the reef to feed, but many are having to decide whether to escape the stressed reefs.

“Faced with a trade-off, sharks must decide whether to leave the relative safety of the reef and expend greater energy to remain cool or stay on a reef in suboptimal conditions but conserve energy.

“We think many are choosing to move into offshore, deeper and cooler waters, which is concerning. Many reefs around the globe have already seen significant declines in sharks due to exploitation and this finding has the potential to exacerbate these trends.”

Although the study didn’t examine the precise mechanisms linking reef stress to shark movement and residency, stress on coral reefs is often closely linked to sea surface temperatures.

“Sharks are ectotherms – cold-blooded animals whose body temperature is regulated by their external environment,” said Dr Michael Williamson from ZSL’s Institute of Zoology and lead author of the paper. “Reef sharks in other regions exhibit behavioural thermoregulation to avoid physiological damage from adverse water temperatures, and this is one of the potential drivers of the findings in this study.”

Importantly, sharks moving away could impact the fragile balance in reef ecosystems.

“As large predators, grey reef sharks play a very important role in coral reef ecosystems,” said Dr Williamson. “They maintain a delicately balanced food web on the reef and they also cycle nutrients onto coral reefs from deeper waters where they often feed. A loss of sharks, and the nutrients they bring, could affect the resilience of reefs during periods of high environmental stress.”

Dr Jacoby said: “As climate change brings increasing uncertainty and more and more frequent extreme stress events, the important ecological role these predators play on coral reefs is likely to change, as they spend more time away from the reefs they are attached to. The implications of this are not yet fully understood but given the complex balance of species and trophic interactions that occur on coral reefs, there will certainly be substantial changes.”

However, there is also some room for optimism in the study’s findings.

Not all the monitored locations saw a decline in habitat use, in fact some acoustic receivers at specific locations saw shark residency actually increase. These findings indicates that there could be localised factors influencing shark decisions, and that some reefs are more resilient to stress. “We now need to find out what exactly is driving decision-making in these animals during periods of stressful conditions,” says Dr Jacoby.

Although these factors were not included in the study, scientists suggest that different reefs can respond differently when exposed to stress.

“Recent research in the Chagos Archipelago, where we conducted our study, has shown that those reefs that have greater nutrient flows from seabirds have significantly enhanced fish biomass and therefore a higher likelihood to be resilient to multiple stressors,” said Dr Wiliamson. “Some of our receivers that were seeing a greater number of sharks residing were also near islands with seabird populations.”

The study is outlined in the paper ‘Environmental stress reduced shark residency to coral reefs’ (https://www.nature.com/articles/s42003-024-06707-3) which has been published in the journal Communications Biology.

The papers authors are: Michael Williamson and David Curnick of ZSL; Emma Tebbs of King’s College London; Francesco Ferretti of Virginia Tech; Aaron Carlisle of the University of Delaware; Taylor Chapple of Oregon State University; Robert Schallert and Barbara Block of Standford University; and David Jacoby of Lancaster University.

DOI: 10.1038/s42003-024-06707-3

Actualización a 18/09/2024: Mamma mía!

https://www.atlanticohoy.com/sociedad/mujer-muerta-en-aguas-cercanas-canarias-por-ataque-tiburon_1536457_102.html

Una mujer muere en aguas cercanas a Canarias tras el ataque de un tiburón
-La fallecida, que viajaba en un catamarán, sufrió la amputación de una pierna e ingresó cadáver en el Hospital Doctor Negrín la noche del lunes | Guardacosta de Marruecos se negaron a acudir al rescate

Actualización a 18/09/2024: Volvemos a la Ruta Norte del Mar Rojo (no creo que veamos tibus) y lo que me acabo de encontrar:

https://www.azti.es/wp-content/uploads/2024/10/shark_identification_guide.pdf

INTRODUCTION:
This identification guide is referred to people that works in marine research and on fisheries, to help improve catch data and statistics on sharks that interact with fisheries especially tuna vessels in the Eastern Atlantic Ocean. The most likely users of the guide are fisheries observers, samplers, fishing masters and crew on board fishing vessels targeting tuna, tuna-like species and sharks in the Eastern Atlantic Ocean. Fisheries training institutions and fishing communities are other potential users.
This guide is a simple way to identify a species within a Family of sharks (Elasmobranchiomorphi: Carcharhinidae ) that have many physical similarities. The guide does not include sharks of different orders, or even sharks of the same order but different families that appear quite frequently in the captures or bycatch of fishing vessels.