Fish Spawning Aggregations in the Mexican CaribbeanAugust 12 2014
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A quick update to those following this project. At the end of September, after several month of work with the fishers, the federal fisheries agency created two completely protected marine reserves to protect the fish spawning aggregations!
Thanks to everyone involved in the project. We´ll continue to explore new aggregation sites.
Next stop - the Nassau grouper aggregation site! Initially things weren´t looking good. We´d taken the ROV out for 3 days but rough weather meant that the captain couldn’t keep the boat hovering over the same spot so it wouldn’t have been safe to deploy the tether. Similarly, I would have soaked my laptop from the spray. But, on the second to last day, just as the fish were getting ready to spawn we got a day with perfect weather!
Predive checks were completed and we were on our way. Controlling the ROV whilst hiding under a towel and a tarp on the boat to be able to see the laptop screen was tricky, but we quickly go the ROV down to 30 metres. The site is deep, the fish are found on top of coral spurs between 25 and 35 metres, but the ROV was doing great - then disaster! We lost control. This happens around minute 4 of the video, (just as we are being to see all the fish). I lost power to the ROV although I could still see the camera. Then after a moment we lost all power. Divers were already in the water and as you´ll see in the video the ROV was rescued by a passing scientist (thanks Will!).
Post dive diagnostic shows that the depth sensor which was glued under the back of the shell came loose and the wires got wrapped around the starboard prop, disabling the motor. The ROV seemed to get confused and shut down. Onboard repairs didn´t get it ready again for a second dive and we are back in the office checking it over.
The video is from the GoPro so we see the entire dive.
Siguiente paso – la agregación de mero! Nos tocó mal tiempo para varios días y no pudimos usar el ROV porque el capitán no pudo mantener la lancha en el mismo lugar, y se iba a mojar la compu… Pero por fin llegó un día con buen tiempo y completamos las revisiones antes del buceo para echarlo al agua. El sitio es profundo (entre 25-35 metros) pero el ROV llegó rápido a los 30 metros, todo bien, empezamos a ver los peces y…. desastre! Perdimos el control del submarino, aprox. minuto 4 del video. Unos buzos que estaban monitoreando el sitio lo rescató (gracias Will!). Lo que pasó es que el profundimetro que estaba pegado al casco se despegó y se enredó con el motor derecha. Lo subimos, intentamos repáralo en la lancha, pero sin éxito. Ya estamos en la oficina poniéndolo en marcha otra vez!
El video es del GoPro y podemos ver todo el buceo.
We finally got the OpenROV in to the ocean on a long trip in to Sian Ka´an to study grouper spawning sites! First stop, the mangroves to check seawater bouyancy and control. Bouyancy was good, but weight was not ideally distributed. Moving the GoPro to the front corrected this. Minor leakage on the port battery tube fixed with parafin film.
Por fin echamos el OpenRov al mar, durante un viaje largo a Sian Ka´an para el estudio de agregaciones de desove de mero. Primera actividad - usarlo en el manglar para checar flotabilidad y control. Flotabilidad bien, pero tuvimos que mover el GoPro hacia el frente para compensar el peso. Se filtró un poco de agua a un tubo de pilas pero se arregló con el apoyo de Adrian Munguia!
After a rather long pause in activities the ROV was back in the test pool today with good buoyancy and perfectly configured controls - its easy to operate!
But.... there was a slight leak in the port battery tube. A new issue, and its not obvious which end the water sneaked in... hopefully a quick fix.
Despues de una pausa larga en las actividades, el submarino esta de regreso en el agua - ya con una buena flotabilidad y control. Pero... ya hay una pequeña fuga en el tubo de la bateria... espero que no tarda mucho en arreglar..
Freshwater test of the COBI OpenROV.
Success. So happy
No leaks, perfect bouyancy.
Couldn't see the screen on the laptop for the glare!
It doesnt like going in straight lines... port motor seems stronger than the other - a lot of spiralling!
Primer prueba del mini submarino
Exitoso! Sin fugas, flotabilidad = perfects
Problemitas - no pude ver la pantalla del laptop por el sol. No le gusta ir en lineas rectas - parece que un motor es mas fuerte y hace muchas vueltas!
Update the software to the most recent version a week or so ago and thought I'd killed it for a moment! No connectivity after update.
But few, all ok, some assistance from the helpful guys on the forum, a little bit of soldering and back on track! Just need to get the last few wires shrink wrapped again and we'll be good to go!
The stress test!! (for me, it was very stressful!) Doing good. Tiny filtration of water in to the starboard battery tube. Working on a fix. Camera tube and port battery tube sealed up!
La prueba de estrés (para mi, que estrés meter el submarino en el agua!) Entró un pocitito de agua a un tubo de las pilas. Lo estamos arreglando. El tubo de la cámara y el otro tubo de las pilas - todo bien!
The Punta Herrero spawning aggregation site monitoring team! The team is made up of trained fishers from the community. They are excellent divers and have an amazing knowledge of fish behaviour in the waters around their community.
El equipo de monitoreo de agregaciones en Punta Herrero. El equipo se esta formado por pescadores de la comunidad costera. Son buzos expertos y tienen un conocimiento impresionante de las aguas alrededor de su comunidad.
A short video of a small school of Cubera Snapper seen in August 2013. The video is a bit grainy as the rough seas caused low light conditions. Many of the spawning sites are multispecific, i.e the same reef area hosts the breeding grounds of several different species. August is towards the end of the spawning season for snappers and we only saw a few on this dive. However, in this region, its still not common to see a school of Cubera snappers.
Un video corto de un cardumen pequeño de pargo cubera, visto en agosto 2013. Muchos de los sitios de agregación son multi-específicos, a decir, que varias especies reproducen en el mismo sitio en diferentes épocas del año. Agosto es cerca del final de la temporada de reproducción de los pargos y no vimos muchos, pero no es común ver un cardumen de cuberas.
A school of juvenile horse-eye jacks come to check out the dive team whilst we searched for spawning aggregations last year!
The presence of jacks can sometimes signal that you are getting close to a spawning site - jacks and similar species can come to feast on the eggs released.
An example of the bathymetric maps produced by the fishers (and highly skilled captains) to help geolocate the aggregation sites. Studies by experts such as Dr. Will Heyman, suggest the sites are located near underwater promontories.
Un ejemplo de los mapas batimétricos producidos por los pescadores (y capitanes expertos) que nos ayuda ubicar los sitios de agregación. Según estudios realizado por expertos como Dr. Will Heyman, los sitios se encuentran cerca de promontorios submarinos.
A quick video of the endangered Nassau Grouper getting ready to spawn in the Sian Ka´an Biosphere Reserve filmed by a scuba diver. These fish are over 50 cm in length and many have changed colour from their normal brown to black and white which is their reproductive colour. As you can see the blue video colour was filmed deep, at about 35 meters. Our next plan is to explore the deeper waters further offshore where its looks like there are more groupers.
Groupers only spawn a few days after the full moon of January, February and March. Snappers behave similarly, only spawning a few days after the full moon of April, May and June. This means the aggregation site can be really hard to find. We work with local fishers as they have the best knowledge of the area.
In one site we recently found over 100 Nassau Grouper getting ready to spawn. The Nassau Grouper is on the IUCN endangered species list. We found the grouper at about 35 meters depth but couldn’t stay long as we were at the limits of safe diving, and we are in a really remote place. It looked like there were more groupers in the deeper water. We hope to explore this area in January with an OpenROV.
In March 2014 we also found a site with >1000 Dog Snapper (see profile pic). It was a huge swirling mass of fish! Even the fishers who were with us had never seen anything like it!
We are a Mexican NGO, Comunidad y Biodiversidad (COBI – www.cobi.org.mx) who work to promote the sustainable use of marine resources.
We work directly with artisanal fishing communities to create no-take zones so that the fishery in that area can recover, bringing benefits to the fishers in the future. We also work closely to improve the fishers´ livelihoods, looking to increase their incomes through improving their business practices and encouraging good sustainable fishing practices that can then be certified by agencies such as the Marine Stewardship Council, so that fishers can get a better price for their catch.
Working with fishers in the Sian Ka´an Biosphere Reserve, Mexico, we were recently successful in establishing several no take zones, two of which include fish spawning aggregation sites -sites of key biological importance as these are the sites that fish such as groupers and snappers come to to breed. They are very easily overfished.
We are currently monitoring the sites but the depth of the spawning aggregations (>35 meters) means that we can only dive for short periods and the diving is potentially risky.
We hope to use an Open ROV to geolocate and document the spawning site to track its recover now that it is closed to fishing.